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--- /dev/null
+++ libmalloc/libmalloc-140.50.6/src/stack_logging_disk.c
@@ -0,0 +1,2801 @@
+/*
+ * Copyright (c) 2007-2013 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#include "internal.h"
+#include "radix_tree.h"
+
+#pragma mark -
+#pragma mark Defines
+
+#if TARGET_OS_EMBEDDED || TARGET_IPHONE_SIMULATOR
+// _malloc_printf(ASL_LEVEL_INFO...) on iOS doesn't show up in the Xcode Console log of the device,
+// but ASL_LEVEL_NOTICE does. So raising the log level is helpful.
+#undef ASL_LEVEL_INFO
+#define ASL_LEVEL_INFO ASL_LEVEL_NOTICE
+#endif
+
+#ifdef TEST_DISK_STACK_LOGGING
+#define _malloc_printf fprintf
+#undef ASL_LEVEL_INFO
+#define ASL_LEVEL_INFO stderr
+#endif
+
+#define STACK_LOGGING_BLOCK_WRITING_SIZE 8192
+#define STACK_LOGGING_MAX_SIMUL_REMOTE_TASKS_INSPECTED 3
+
+#define BACKTRACE_UNIQUING_DEBUG 0
+
+// The expansion factor controls the shifting up of table size. A factor of 1 will double the size upon expanding,
+// 2 will quadruple the size, etc. Maintaining a 66% fill in an ideal table requires the collision allowance to
+// increase by 3 for every quadrupling of the table size (although this the constant applied to insertion
+// performance O(c*n))
+#define EXPAND_FACTOR 2
+#define COLLISION_GROWTH_RATE 3
+
+// For a uniquing table, the useful node size is slots := floor(table_byte_size / (2 * sizeof(mach_vm_address_t)))
+// Some useful numbers for the initial max collision value (desiring 66% fill):
+// 16K-23K slots -> 16 collisions
+// 24K-31K slots -> 17 collisions
+// 32K-47K slots -> 18 collisions
+// 48K-79K slots -> 19 collisions
+// 80K-96K slots -> 20 collisions
+#define INITIAL_MAX_COLLIDE 19
+#define DEFAULT_UNIQUING_PAGE_SIZE 256
+
+#pragma mark -
+#pragma mark Macros
+
+#define STACK_LOGGING_FLAGS_SHIFT 56
+#define STACK_LOGGING_USER_TAG_SHIFT 24
+#define STACK_LOGGING_FLAGS(longlongvar) (uint32_t)((uint64_t)(longlongvar) >> STACK_LOGGING_FLAGS_SHIFT)
+#define STACK_LOGGING_FLAGS_AND_USER_TAG(longlongvar) \
+ (uint32_t)(STACK_LOGGING_FLAGS(longlongvar) | (((uint64_t)(longlongvar)&0x00FF000000000000ull) >> STACK_LOGGING_USER_TAG_SHIFT))
+
+#define STACK_LOGGING_OFFSET_MASK 0x0000FFFFFFFFFFFFull
+#define STACK_LOGGING_OFFSET(longlongvar) ((longlongvar)&STACK_LOGGING_OFFSET_MASK)
+
+#define STACK_LOGGING_OFFSET_AND_FLAGS(longlongvar, type_flags) \
+ (((uint64_t)(longlongvar)&STACK_LOGGING_OFFSET_MASK) | ((uint64_t)(type_flags) << STACK_LOGGING_FLAGS_SHIFT) | \
+ (((uint64_t)(type_flags)&0xFF000000ull) << STACK_LOGGING_USER_TAG_SHIFT))
+
+#pragma mark -
+#pragma mark Types
+
+typedef struct {
+ uintptr_t argument;
+ uintptr_t address;
+ uint64_t offset_and_flags; // top 8 bits are actually the flags!
+} stack_logging_index_event;
+
+typedef struct {
+ uint32_t argument;
+ uint32_t address;
+ uint64_t offset_and_flags; // top 8 bits are actually the flags!
+} stack_logging_index_event32;
+
+typedef struct {
+ uint64_t argument;
+ uint64_t address;
+ uint64_t offset_and_flags; // top 8 bits are actually the flags!
+} stack_logging_index_event64;
+
+// backtrace uniquing table chunks used in client-side stack log reading code,
+// in case we can't read the whole table in one mach_vm_read() call.
+typedef struct table_chunk_header {
+ uint64_t num_nodes_in_chunk;
+ uint64_t table_chunk_size;
+ mach_vm_address_t *table_chunk;
+ struct table_chunk_header *next_table_chunk_header;
+} table_chunk_header_t;
+
+#pragma pack(push, 4)
+typedef struct backtrace_uniquing_table {
+ uint64_t numPages; // number of pages of the table
+ uint64_t numNodes;
+ uint64_t tableSize;
+ uint64_t untouchableNodes;
+ mach_vm_address_t table_address;
+ int32_t max_collide;
+// 'table_address' is just an always 64-bit version of the pointer-sized 'table' field to remotely read;
+// it's important that the offset of 'table_address' in the struct does not change between 32 and 64-bit.
+#if BACKTRACE_UNIQUING_DEBUG
+ uint64_t nodesFull;
+ uint64_t backtracesContained;
+#endif
+ union {
+ mach_vm_address_t *table; // in "target" process; allocated using vm_allocate()
+ table_chunk_header_t *first_table_chunk_hdr; // in analysis process
+ } u;
+ uint64_t max_table_size;
+ bool in_client_process : 1;
+ bool nodes_use_refcount : 1;
+ unsigned refcount;
+} backtrace_uniquing_table;
+#pragma pack(pop)
+
+// for storing/looking up allocations that haven't yet be written to disk; consistent size across 32/64-bit processes.
+// It's important that these fields don't change alignment due to the architecture because they may be accessed from an
+// analyzing process with a different arch - hence the pragmas.
+#pragma pack(push, 4)
+typedef struct {
+ uint64_t start_index_offset;
+ uint32_t next_free_index_buffer_offset;
+ char index_buffer[STACK_LOGGING_BLOCK_WRITING_SIZE];
+ backtrace_uniquing_table *uniquing_table;
+ struct radix_tree *vm_stackid_table;
+ uint64_t vm_stackid_table_size;
+} stack_buffer_shared_memory;
+#pragma pack(pop)
+
+// target process address -> record table (for __mach_stack_logging_get_frames)
+typedef struct {
+ uint64_t address;
+ uint64_t index_file_offset;
+} remote_index_node;
+
+// for caching index information client-side:
+typedef struct {
+ size_t cache_size;
+ size_t cache_node_capacity;
+ uint32_t collision_allowance;
+ remote_index_node *table_memory; // this can be malloced; it's on the client side.
+ stack_buffer_shared_memory *shmem; // shared memory
+ stack_buffer_shared_memory snapshot; // memory snapshot of the remote process' shared memory
+ uint32_t last_pre_written_index_size;
+ uint64_t last_index_file_offset;
+ backtrace_uniquing_table uniquing_table_snapshot; // snapshot of the remote process' uniquing table
+ boolean_t lite_mode;
+ struct radix_tree *vm_stackid_table;
+} remote_index_cache;
+
+// for reading stack history information from remote processes:
+typedef struct {
+ task_t remote_task;
+ pid_t remote_pid;
+ int32_t task_is_64_bit;
+ boolean_t task_uses_lite_mode;
+ int32_t in_use_count;
+ FILE *index_file_stream;
+ uint64_t remote_stack_buffer_shared_memory_address;
+ remote_index_cache *cache;
+} remote_task_file_streams;
+
+typedef mach_vm_address_t slot_address;
+typedef uint64_t slot_parent;
+typedef uint64_t slot_refcount;
+typedef uint64_t table_slot_index;
+
+#pragma pack(push,16)
+typedef struct {
+ union {
+ struct {
+ uint64_t slot0;
+ uint64_t slot1;
+ } slots;
+
+ struct {
+ slot_address address:48;
+ slot_parent parent:32;
+ slot_refcount refcount:48;
+ } refcount_slot;
+
+ struct {
+ slot_address address:64;
+ slot_parent parent:64;
+ } normal_slot;
+ };
+
+} table_slot_t;
+#pragma pop
+
+_Static_assert(sizeof(table_slot_t) == 16, "table_slot_t must be 128 bits");
+
+#pragma mark -
+#pragma mark Constants/Globals
+
+int stack_logging_enable_logging = 0;
+int stack_logging_dontcompact = 0;
+int stack_logging_finished_init = 0;
+int stack_logging_postponed = 0;
+int stack_logging_mode = stack_logging_mode_none;
+
+#define MAX_PARENT_NORMAL
+#define MAX_PARENT_REFCOUNT
+
+static const slot_parent slot_no_parent_normal = 0xFFFFFFFFFFFFFFFF; // 64 bits
+static const slot_parent slot_no_parent_refcount = 0xFFFFFFFF; // 32 bits
+
+static _malloc_lock_s stack_logging_lock = _MALLOC_LOCK_INIT;
+static vm_address_t thread_doing_logging = 0;
+
+// single-thread access variables
+static stack_buffer_shared_memory *pre_write_buffers;
+static vm_address_t *stack_buffer;
+static uintptr_t last_logged_malloc_address = 0;
+
+// Constants to define part of stack logging file path names.
+// File names are of the form stack-logs.<pid>.<address>.<progname>.XXXXXX.index
+// where <address> is the address of the pre_write_buffers VM region in the target
+// process that will need to be mapped into analysis tool processes.
+static const char *stack_log_file_base_name = "stack-logs.";
+static const char *stack_log_file_suffix = ".index";
+
+static FILE *open_log_file_at_path(char *pathname, remote_task_file_streams *streams);
+
+char *__stack_log_file_path__ = NULL;
+static int index_file_descriptor = -1;
+
+// for accessing remote log files
+static remote_task_file_streams remote_fds[STACK_LOGGING_MAX_SIMUL_REMOTE_TASKS_INSPECTED];
+static uint32_t next_remote_task_fd = 0;
+static uint32_t remote_task_fd_count = 0;
+static _malloc_lock_s remote_fd_list_lock = _MALLOC_LOCK_INIT;
+
+uint64_t __mach_stack_logging_shared_memory_address = 0;
+
+// activation variables
+static int logging_use_compaction = 1; // set this to zero to always disable compaction.
+
+// We set malloc_logger to NULL to disable logging, if we encounter errors
+// during file writing
+typedef void(malloc_logger_t)(uint32_t type,
+ uintptr_t arg1,
+ uintptr_t arg2,
+ uintptr_t arg3,
+ uintptr_t result,
+ uint32_t num_hot_frames_to_skip);
+extern malloc_logger_t *malloc_logger;
+
+extern malloc_logger_t *__syscall_logger; // use this to set up syscall logging (e.g., vm_allocate, vm_deallocate, mmap, munmap)
+
+#pragma mark -
+#pragma mark In-Memory Backtrace Uniquing
+
+static __attribute__((always_inline)) inline void *
+sld_allocate_pages(uint64_t memSize)
+{
+ mach_vm_address_t allocatedMem = 0ull;
+ if (mach_vm_allocate(mach_task_self(), &allocatedMem, memSize, VM_FLAGS_ANYWHERE | VM_MAKE_TAG(VM_MEMORY_ANALYSIS_TOOL)) !=
+ KERN_SUCCESS) {
+ malloc_printf("allocate_pages(): virtual memory exhausted!\n");
+ }
+ return (void *)(uintptr_t)allocatedMem;
+}
+
+static __attribute__((always_inline)) inline int
+sld_deallocate_pages(void *memPointer, uint64_t memSize)
+{
+ return mach_vm_deallocate(mach_task_self(), (mach_vm_address_t)(uintptr_t)memPointer, memSize);
+}
+
+static const uint64_t max_table_size_lite = UINT32_MAX;
+static const uint64_t max_table_size_normal = UINT64_MAX;
+
+static backtrace_uniquing_table *
+__create_uniquing_table(boolean_t lite_mode)
+{
+ backtrace_uniquing_table *uniquing_table =
+ (backtrace_uniquing_table *)sld_allocate_pages((uint64_t)round_page(sizeof(backtrace_uniquing_table)));
+ if (!uniquing_table) {
+ return NULL;
+ }
+ bzero(uniquing_table, sizeof(backtrace_uniquing_table));
+ uniquing_table->numPages = DEFAULT_UNIQUING_PAGE_SIZE;
+ uniquing_table->tableSize = uniquing_table->numPages * vm_page_size;
+ uniquing_table->numNodes = ((uniquing_table->tableSize / (sizeof(mach_vm_address_t) * 2)) >> 1) << 1; // make sure it's even.
+ uniquing_table->u.table = (mach_vm_address_t *)(uintptr_t)sld_allocate_pages(uniquing_table->tableSize);
+ uniquing_table->table_address = (uintptr_t)uniquing_table->u.table;
+ uniquing_table->max_collide = INITIAL_MAX_COLLIDE;
+ uniquing_table->untouchableNodes = 0;
+ uniquing_table->max_table_size = (lite_mode) ? max_table_size_lite : max_table_size_normal;
+ uniquing_table->nodes_use_refcount = lite_mode;
+ uniquing_table->in_client_process = 0;
+
+#if BACKTRACE_UNIQUING_DEBUG
+ malloc_printf("create_uniquing_table(): creating. size: %lldKB == %lldMB, numnodes: %lld (%lld untouchable)\n",
+ uniquing_table->tableSize >> 10, uniquing_table->tableSize >> 20, uniquing_table->numNodes,
+ uniquing_table->untouchableNodes);
+ malloc_printf("create_uniquing_table(): table: %p; end: %p\n", uniquing_table->u.table,
+ (void *)((uintptr_t)uniquing_table->u.table + (uintptr_t)uniquing_table->tableSize));
+#endif
+ return uniquing_table;
+}
+
+static void
+__destroy_uniquing_table(backtrace_uniquing_table *table)
+{
+ assert(!table->in_client_process);
+ sld_deallocate_pages(table->u.table, table->tableSize);
+ sld_deallocate_pages(table, sizeof(backtrace_uniquing_table));
+}
+
+static boolean_t
+__expand_uniquing_table(backtrace_uniquing_table *uniquing_table)
+{
+ assert(!uniquing_table->in_client_process);
+ mach_vm_address_t *oldTable = uniquing_table->u.table;
+ uint64_t oldsize = uniquing_table->tableSize;
+ uint64_t oldnumnodes = uniquing_table->numNodes;
+
+ uint64_t newsize = (uniquing_table->numPages << EXPAND_FACTOR) * vm_page_size;
+
+ if (newsize > uniquing_table->max_table_size) {
+ malloc_printf("no more space in uniquing table\n");
+ return false;
+ }
+
+ uniquing_table->numPages = uniquing_table->numPages << EXPAND_FACTOR;
+ uniquing_table->tableSize = uniquing_table->numPages * vm_page_size;
+ uniquing_table->numNodes = ((uniquing_table->tableSize / (sizeof(mach_vm_address_t) * 2)) >> 1) << 1; // make sure it's even.
+ mach_vm_address_t *newTable = (mach_vm_address_t *)(uintptr_t)sld_allocate_pages(uniquing_table->tableSize);
+
+ uniquing_table->u.table = newTable;
+ uniquing_table->table_address = (uintptr_t)uniquing_table->u.table;
+ uniquing_table->max_collide = uniquing_table->max_collide + COLLISION_GROWTH_RATE;
+
+ if (mach_vm_copy(mach_task_self(), (mach_vm_address_t)(uintptr_t)oldTable, oldsize, (mach_vm_address_t)(uintptr_t)newTable) !=
+ KERN_SUCCESS) {
+ malloc_printf("expandUniquingTable(): VMCopyFailed\n");
+ }
+ uniquing_table->untouchableNodes = oldnumnodes;
+
+#if BACKTRACE_UNIQUING_DEBUG
+ malloc_printf(
+ "expandUniquingTable(): expanded from nodes full: %lld of: %lld (~%2d%%); to nodes: %lld (inactive = %lld); unique "
+ "bts: %lld\n",
+ uniquing_table->nodesFull, oldnumnodes, (int)(((uniquing_table->nodesFull * 100.0) / (double)oldnumnodes) + 0.5),
+ uniquing_table->numNodes, uniquing_table->untouchableNodes, uniquing_table->backtracesContained);
+ malloc_printf("expandUniquingTable(): allocate: %p; end: %p\n", newTable,
+ (void *)((uintptr_t)newTable + (uintptr_t)(uniquing_table->tableSize)));
+ malloc_printf("expandUniquingTable(): deallocate: %p; end: %p\n", oldTable, (void *)((uintptr_t)oldTable + (uintptr_t)oldsize));
+ malloc_printf("expandUniquingTable(): new size = %llu\n", newsize);
+#endif
+
+ if (sld_deallocate_pages(oldTable, oldsize) != KERN_SUCCESS) {
+ malloc_printf("expandUniquingTable(): mach_vm_deallocate failed. [%p]\n", uniquing_table->u.table);
+ }
+
+ return true;
+}
+
+static void
+add_new_slot(table_slot_t *table_slot, mach_vm_address_t address, table_slot_index parent, bool use_refcount, size_t ptr_size)
+{
+ assert(use_refcount == (ptr_size > 0));
+
+ table_slot_t new_slot;
+
+ if (use_refcount) {
+ new_slot.refcount_slot.address = address;
+ new_slot.refcount_slot.parent = parent;
+ new_slot.refcount_slot.refcount = ptr_size;
+ } else {
+ new_slot.normal_slot.address = address;
+ new_slot.normal_slot.parent = parent;
+ }
+
+ *table_slot = new_slot;
+}
+
+static void
+increment_slot_refcount(table_slot_t *table_slot, size_t ptr_size)
+{
+ table_slot->refcount_slot.refcount += ptr_size;
+}
+
+static int
+enter_frames_in_table(backtrace_uniquing_table *uniquing_table, uint64_t *foundIndex, mach_vm_address_t *frames, int32_t count, size_t ptr_size)
+{
+ assert(!uniquing_table->in_client_process);
+ boolean_t use_refcount = (ptr_size > 0);
+
+ // The hash values need to be the same size as the addresses (because we use the value -1), for clarity, define a new type
+ typedef mach_vm_address_t hash_index_t;
+
+ hash_index_t uParent = use_refcount ? slot_no_parent_refcount : slot_no_parent_normal;
+ hash_index_t modulus = (uniquing_table->numNodes-uniquing_table->untouchableNodes-1);
+
+ int32_t lcopy = count;
+ int32_t returnVal = 1;
+ hash_index_t hash_multiplier = ((uniquing_table->numNodes - uniquing_table->untouchableNodes)/(uniquing_table->max_collide*2+1));
+
+ while (--lcopy >= 0) {
+ mach_vm_address_t thisPC = frames[lcopy];
+ hash_index_t hash = uniquing_table->untouchableNodes + (((uParent << 4) ^ (thisPC >> 2)) % modulus);
+ int32_t collisions = uniquing_table->max_collide;
+
+ while (collisions--) {
+ table_slot_t *table_slot = (table_slot_t *) (uniquing_table->u.table + (hash * 2));
+
+ if (table_slot->slots.slot0 == 0 && table_slot->slots.slot1 == 0) {
+ add_new_slot(table_slot, thisPC, uParent, uniquing_table->nodes_use_refcount, ptr_size);
+ uParent = hash;
+ break;
+ }
+
+ slot_address address = use_refcount ? table_slot->refcount_slot.address : table_slot->normal_slot.address;
+ slot_parent parent = use_refcount ? table_slot->refcount_slot.parent : table_slot->normal_slot.parent;
+
+ if (address == thisPC && parent == uParent) {
+ uParent = hash;
+
+ if (use_refcount)
+ increment_slot_refcount(table_slot, ptr_size);
+
+ break;
+ }
+
+ hash += collisions * hash_multiplier + 1;
+
+ if (hash >= uniquing_table->numNodes) {
+ hash -= (uniquing_table->numNodes - uniquing_table->untouchableNodes); // wrap around.
+ }
+ }
+
+ if (collisions < 0) {
+ returnVal = 0;
+ break;
+ }
+ }
+
+ if (returnVal) {
+ *foundIndex = uParent;
+ }
+
+ return returnVal;
+}
+
+#pragma mark -
+#pragma mark Disk Stack Logging
+
+// pre-declarations
+static void delete_log_files(void);
+static int delete_logging_file(char *log_location);
+static bool getenv_from_process(pid_t pid, char *env_var_name, char *env_var_value_buf, size_t max_path_len);
+
+#define BASE10 10
+#define BASE16 16
+
+static void
+append_int(char *filename, uint64_t inputValue, unsigned base, size_t maxLength)
+{
+ const char *digits = "0123456789abcdef";
+ if (base > strlen(digits)) {
+ return; // sanity check
+ }
+ size_t len = strlen(filename);
+
+ uint32_t count = 0;
+ uint64_t value = inputValue;
+ while (value > 0) {
+ value /= base;
+ count++;
+ }
+
+ if (len + count >= maxLength) {
+ return; // don't modify the string if it would violate maxLength
+ }
+ filename[len + count] = '\0';
+
+ value = inputValue;
+ uint32_t i;
+ for (i = 0; i < count; i++) {
+ filename[len + count - 1 - i] = digits[value % base];
+ value /= base;
+ }
+}
+
+/*
+ * <rdar://problem/11128080> if we needed to call confstr during init then setting this
+ * flag will postpone stack logging until after Libsystem's initialiser has run.
+ */
+static void
+postpone_stack_logging(void)
+{
+ _malloc_printf(ASL_LEVEL_INFO, "stack logging postponed until after initialization.\n");
+ stack_logging_postponed = 1;
+}
+
+/*
+ * Check various logging directory options, in order of preference:
+ *
+ * value of MallocStackLoggingDirectory env var if user has set it. Typically
+ * used on Mac OS X to write to a non-root file system with more free space.
+ *
+ * _PATH_TMP - /tmp usually writable for desktop apps and internal iOS apps
+ *
+ * value of TMPDIR env var - for sandboxed apps that can't write into /tmp
+ *
+ * confstr(_CS_DARWIN_USER_TEMP_DIR, ...) - should be same as TMPDIR if that is set,
+ * but will create it safely if it doesn't yet exist. (See <rdar://problem/4706096>)
+ *
+ * Allocating and releasing target buffer is the caller's responsibility.
+ */
+static bool
+get_writeable_logging_directory(char *target)
+{
+ if (!target) {
+ return false;
+ }
+
+ char *evn_log_directory = getenv("MallocStackLoggingDirectory");
+ if (evn_log_directory) {
+ if (-1 != access(evn_log_directory, W_OK)) {
+ strlcpy(target, evn_log_directory, (size_t)PATH_MAX);
+ return true;
+ } else {
+ _malloc_printf(ASL_LEVEL_INFO, "MallocStackLoggingDirectory env var set to unwritable path '%s'\n", evn_log_directory);
+ }
+ }
+
+ if (-1 != access(_PATH_TMP, W_OK)) {
+ strlcpy(target, _PATH_TMP, (size_t)PATH_MAX);
+ return true;
+ }
+
+ evn_log_directory = getenv("TMPDIR");
+ if (evn_log_directory && (-1 != access(evn_log_directory, W_OK))) {
+ strlcpy(target, evn_log_directory, (size_t)PATH_MAX);
+ return true;
+ }
+
+ if (stack_logging_finished_init) {
+ size_t n = confstr(_CS_DARWIN_USER_TEMP_DIR, target, (size_t)PATH_MAX);
+ if ((n > 0) && (n < PATH_MAX)) {
+ return true;
+ }
+ } else {
+ /* <rdar://problem/11128080> Can't call confstr during init, so postpone
+ * logging till after */
+ postpone_stack_logging();
+ }
+ *target = '\0';
+ return false;
+}
+
+// Stolen from libc. Ugly hack because arc4random uses malloc so we can't call Libc's mkstemps.
+int getentropy(void *, size_t);
+static int
+my_mkstemps(char *path, size_t slen)
+{
+ char *start, *trv, *suffp, *carryp;
+ char *pad;
+ char carrybuf[MAXPATHLEN];
+ int fd;
+
+ for (trv = path; *trv != '\0'; ++trv) {
+ ;
+ }
+ trv -= slen;
+ suffp = trv;
+ --trv;
+
+ /* Fill space with random characters */
+ uint8_t randbuf[8];
+ unsigned int randbuf_offset = 0;
+ getentropy(randbuf, sizeof(randbuf));
+ static const char padchar[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+ while (trv >= path && *trv == 'X') {
+ *trv-- = padchar[randbuf[randbuf_offset++ % sizeof(randbuf)] % sizeof(padchar)];
+ }
+ start = trv + 1;
+
+ /* save first combination of random characters */
+ memcpy(carrybuf, start, suffp - start);
+
+ for (;;) {
+ if ((fd = open(path, O_CREAT | O_EXCL | O_RDWR, 0600)) >= 0) {
+ return fd;
+ }
+ if (errno != EEXIST) {
+ return -1;
+ }
+
+ /* If we have a collision, cycle through the space of filenames */
+ for (trv = start, carryp = carrybuf;;) {
+ /* have we tried all possible permutations? */
+ if (trv == suffp) {
+ return -1; /* yes - exit with EEXIST */
+ }
+ pad = strchr(padchar, *trv);
+ if (pad == NULL) {
+ /* this should never happen */
+ errno = EIO;
+ return -1;
+ }
+ /* increment character */
+ *trv = (*++pad == '\0') ? padchar[0] : *pad;
+ /* carry to next position? */
+ if (*trv == *carryp) {
+ /* increment position and loop */
+ ++trv;
+ ++carryp;
+ } else {
+ /* try with new name */
+ break;
+ }
+ }
+ }
+}
+
+// If successful, returns path to log file that was created, otherwise NULL.
+static char *
+create_log_file()
+{
+ pid_t pid = getpid();
+ const char *progname = getprogname();
+ char *created_log_location = NULL;
+
+ if (__stack_log_file_path__ == NULL) {
+ // On first use, allocate space directly from the OS without using malloc
+ __stack_log_file_path__ = sld_allocate_pages((uint64_t)round_page(PATH_MAX));
+ if (__stack_log_file_path__ == NULL) {
+ _malloc_printf(ASL_LEVEL_INFO, "unable to allocate memory for stack log file path\n");
+ return NULL;
+ }
+ }
+
+ if (!get_writeable_logging_directory(__stack_log_file_path__)) {
+ if (!stack_logging_postponed) {
+ _malloc_printf(ASL_LEVEL_INFO, "No writeable tmp dir\n");
+ }
+ return NULL;
+ }
+
+ // Add the '/' only if it's not already there. Having multiple '/' characters works
+ // but is unsightly when we print these stack log file names out.
+ size_t stack_log_len = strlen(__stack_log_file_path__);
+ if (__stack_log_file_path__[stack_log_len - 1] != '/') {
+ // use strlcat to null-terminate for the next strlcat call, and to check buffer size
+ strlcat(__stack_log_file_path__ + stack_log_len, "/", (size_t)PATH_MAX);
+ }
+
+ // Append the file name to __stack_log_file_path__ but don't use snprintf since
+ // it can cause malloc() calls.
+ //
+ // The file name is of the form "stack-logs.<pid>.<address>.<progname>.XXXXXX.index"
+ // where <address> is the address of the pre_write_buffers VM region in the target
+ // process that will need to be mapped into analysis tool processes. We used to just
+ // use a shared memory segment for that, but sandbox'ed target apps may not be able
+ // to create shared memory segments so including the address of the VM region in the
+ // file name is a simple way to communicate the address to analysis tools so the
+ // stack log reading code can map in the region with mach_vm_remap().
+
+ strlcat(__stack_log_file_path__, stack_log_file_base_name, (size_t)PATH_MAX);
+ append_int(__stack_log_file_path__, pid, BASE10, (size_t)PATH_MAX);
+ strlcat(__stack_log_file_path__, ".", (size_t)PATH_MAX);
+ append_int(__stack_log_file_path__, (uint64_t)pre_write_buffers, BASE16, (size_t)PATH_MAX);
+ if (progname && progname[0] != '\0') {
+ strlcat(__stack_log_file_path__, ".", (size_t)PATH_MAX);
+ strlcat(__stack_log_file_path__, progname, (size_t)PATH_MAX);
+ }
+ strlcat(__stack_log_file_path__, ".XXXXXX", (size_t)PATH_MAX);
+ strlcat(__stack_log_file_path__, stack_log_file_suffix, (size_t)PATH_MAX);
+
+ // Securely create the log file.
+ if ((index_file_descriptor = my_mkstemps(__stack_log_file_path__, (int)strlen(stack_log_file_suffix))) != -1) {
+ _malloc_printf(ASL_LEVEL_INFO, "stack logs being written into %s\n", __stack_log_file_path__);
+ created_log_location = __stack_log_file_path__;
+ } else {
+ _malloc_printf(ASL_LEVEL_INFO, "unable to create stack logs at %s\n", __stack_log_file_path__);
+ __stack_log_file_path__[0] = '\0';
+ created_log_location = NULL;
+ }
+
+ return created_log_location;
+}
+
+// This function may be called from either the target process when exiting, or from either the the target process or
+// a stack log analysis process, when reaping orphaned stack log files.
+// Returns -1 if the files exist and they couldn't be removed, returns 0 otherwise.
+static int
+delete_logging_file(char *log_location)
+{
+ if (log_location == NULL || log_location[0] == '\0') {
+ return 0;
+ }
+
+ struct stat statbuf;
+ if (unlink(log_location) != 0 && stat(log_location, &statbuf) == 0) {
+ return -1;
+ }
+ return 0;
+}
+
+// This function will be called from atexit() in the target process.
+static void
+delete_log_files(void)
+{
+ if (__stack_log_file_path__ && __stack_log_file_path__[0]) {
+ if (delete_logging_file(__stack_log_file_path__) == 0) {
+ _malloc_printf(ASL_LEVEL_INFO, "stack logs deleted from %s\n", __stack_log_file_path__);
+ __stack_log_file_path__[0] = '\0';
+ } else {
+ _malloc_printf(ASL_LEVEL_INFO, "unable to delete stack logs from %s\n", __stack_log_file_path__);
+ }
+ }
+}
+
+static bool
+is_process_running(pid_t pid)
+{
+ struct kinfo_proc kpt[1];
+ size_t size = sizeof(struct kinfo_proc);
+ int mib[] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
+
+ sysctl(mib, 4, kpt, &size, NULL, (size_t)0); // size is either 1 or 0 entries when we ask for a single pid
+
+ return (size == sizeof(struct kinfo_proc));
+}
+
+// Stack log files can be quite large and aren't useful after the process that created them no longer exists because
+// the stack backtrace uniquing tree was only kept in the process memory, not on disk. Normally the log files
+// should get removed when the process exits, by the delete_log_files() atexit function. However, there are
+// several situations in which that atexit function doesn't get called so the log files remain:
+// - if the process crashes or is force-killed
+// - if the app supported sudden termination, and was terminated through that
+// - if a process such as a shell execs another binary to transform the pid into a different process;
+// the new process will get a new log file but the old one would still be there.
+//
+// So, reap any stack log files for processes that no longer exist, or for the current process if we find a file
+// other than __stack_log_file_path__
+//
+// This function looks for log files with prefix name "stack-logs.<pid>." underneath <directory>.
+// <remaining_path_format> specifies a simple pattern of where stack logs can be down inside <directory>.
+// The pattern is essentially a relative path, where a level that start with '<' matches any name, otherwise
+// it has to be an exact name match. See the calling function for examples.
+static void
+reap_orphaned_log_files_in_hierarchy(char *directory, char *remaining_path_format, pid_t target_pid, remote_task_file_streams *streams)
+{
+ DIR *dp;
+ struct dirent *entry;
+
+ // Ensure that we can access this directory - permissions or sandbox'ing might prevent it.
+ if (access(directory, R_OK | W_OK | X_OK) == -1 || (dp = opendir(directory)) == NULL) {
+ //_malloc_printf(ASL_LEVEL_INFO, "reaping: no access to %s\n", directory);
+ return;
+ }
+
+ char pathname[PATH_MAX];
+ strlcpy(pathname, directory, (size_t)PATH_MAX);
+ size_t pathname_len = strlen(pathname);
+ if (pathname[pathname_len - 1] != '/') {
+ pathname[pathname_len++] = '/';
+ }
+ char *suffix = pathname + pathname_len;
+
+ // Recurse down to deeper levels of the temp directory hierarchy if necessary.
+ if (remaining_path_format) {
+ char *separator = remaining_path_format;
+ while (*separator != '/' && *separator != '\0') {
+ separator++;
+ }
+ size_t length_to_match = (*remaining_path_format == '<') ? 0 : separator - remaining_path_format;
+ char *next_remaining_path_format = (*separator == '\0') ? NULL : separator + 1;
+
+ while ((entry = readdir(dp)) != NULL) {
+ if (entry->d_type == DT_DIR && entry->d_name[0] != '.') {
+ if (length_to_match > 0 && strncmp(entry->d_name, remaining_path_format, length_to_match) != 0) {
+ continue;
+ }
+ strlcpy(suffix, entry->d_name, (size_t)PATH_MAX - pathname_len);
+ reap_orphaned_log_files_in_hierarchy(pathname, next_remaining_path_format, target_pid, streams);
+ }
+ }
+ closedir(dp);
+
+ return;
+ }
+
+ // OK, we found a lowest-level directory matching <remaining_path_format>, and we have access to it.
+ // Reap any unnecessary stack log files in here.
+
+ //_malloc_printf(ASL_LEVEL_INFO, "reaping: looking in %s\n", directory);
+
+ // __stack_log_file_path__ may be NULL if this code is running in an analysis tool client process that is not
+ // itself running with MallocStackLogging set.
+ char *curproc_stack_log_file = __stack_log_file_path__ ? strrchr(__stack_log_file_path__, '/') + 1 : NULL;
+ pid_t curpid = getpid();
+ size_t prefix_length = strlen(stack_log_file_base_name);
+
+ while ((entry = readdir(dp)) != NULL) {
+ if ((entry->d_type == DT_REG || entry->d_type == DT_LNK) &&
+ (strncmp(entry->d_name, stack_log_file_base_name, prefix_length) == 0)) {
+ long pid = strtol(&entry->d_name[prefix_length], (char **)NULL, 10);
+ if (pid == target_pid && streams != NULL) {
+ strlcpy(suffix, entry->d_name, (size_t)PATH_MAX - pathname_len);
+ open_log_file_at_path(pathname, streams);
+ }
+ else if (!is_process_running((pid_t)pid) ||
+ (pid == curpid && curproc_stack_log_file && strcmp(entry->d_name, curproc_stack_log_file) != 0)) {
+ strlcpy(suffix, entry->d_name, (size_t)PATH_MAX - pathname_len);
+ if (delete_logging_file(pathname) == 0) {
+ if (pid == curpid) {
+ _malloc_printf(ASL_LEVEL_INFO, "stack logs deleted from %s\n", pathname);
+ } else {
+ _malloc_printf(ASL_LEVEL_INFO, "process %ld no longer exists, stack logs deleted from %s\n", pid, pathname);
+ }
+ }
+ }
+ }
+ }
+ closedir(dp);
+}
+
+static void
+reap_orphaned_log_files(pid_t target_pid, remote_task_file_streams *streams)
+{
+ reap_orphaned_log_files_in_hierarchy(_PATH_TMP, NULL, target_pid, streams);
+
+ char *env_var_names[] = {"TMPDIR", "MallocStackLoggingDirectory"};
+ for (unsigned i = 0; i < sizeof(env_var_names) / sizeof(char *); i++) {
+ char directory[PATH_MAX];
+ bool success = getenv_from_process(target_pid, env_var_names[i], directory, sizeof(directory));
+ if (success && strcmp(directory, _PATH_TMP) != 0) {
+ reap_orphaned_log_files_in_hierarchy(directory, NULL, target_pid, streams);
+ }
+ }
+
+ // Now reap files left over in any other accessible app-specific temp directories.
+ // These could be from sandbox'ed apps.
+#if TARGET_OS_EMBEDDED
+ char *root_of_temp_directories = "/private/var/mobile/Containers/Data/Application"; // ugh - hard-coding to user name "mobile".
+ // Works for all iOS's up to now.
+ char *temp_directories_path_format = "<application-UUID>/tmp";
+#else
+ char *root_of_temp_directories = "/private/var/folders";
+ char *temp_directories_path_format = "<xx>/<random>/T";
+#endif
+ reap_orphaned_log_files_in_hierarchy(root_of_temp_directories, temp_directories_path_format, target_pid, streams);
+}
+
+/*
+ * Since there a many errors that could cause stack logging to get disabled, this is a convenience method
+ * for disabling any future logging in this process and for informing the user.
+ */
+static void
+disable_stack_logging(void)
+{
+ _malloc_printf(ASL_LEVEL_INFO, "stack logging disabled due to previous errors.\n");
+ stack_logging_enable_logging = 0;
+ malloc_logger = NULL;
+ __syscall_logger = NULL;
+ disable_stack_logging_lite();
+}
+
+static boolean_t uniquing_table_memory_was_deleted = false;
+
+__attribute__((visibility("hidden"))) boolean_t
+__uniquing_table_memory_was_deleted(void)
+{
+ return uniquing_table_memory_was_deleted;
+}
+
+__attribute__((visibility("hidden"))) void
+__delete_uniquing_table_memory_while_locked(void)
+{
+ // Clean out the memory (if not done already)
+ if (pre_write_buffers && pre_write_buffers->uniquing_table != NULL) {
+ __destroy_uniquing_table(pre_write_buffers->uniquing_table);
+ pre_write_buffers->uniquing_table = NULL;
+ uniquing_table_memory_was_deleted = true;
+ }
+
+ // Clear the shared memory address so client tools won't look for the uniquing table memory
+ __mach_stack_logging_shared_memory_address = 0;
+}
+
+/* A wrapper around write() that will try to reopen the index/stack file and
+ * write to it if someone closed it underneath us (e.g. the process we just
+ * started decide to close all file descriptors except stin/err/out). Some
+ * programs like to do that and calling abort() on them is rude.
+ */
+static ssize_t
+robust_write(int fd, const void *buf, size_t nbyte)
+{
+ extern int errno;
+ ssize_t written = write(fd, buf, nbyte);
+ if (written == -1 && errno == EBADF) {
+ char *file_to_reopen = NULL;
+ int *fd_to_reset = NULL;
+
+ // descriptor was closed on us. We need to reopen it
+ if (fd == index_file_descriptor) {
+ file_to_reopen = __stack_log_file_path__;
+ fd_to_reset = &index_file_descriptor;
+ } else {
+ // We don't know about this file. Return (and abort()).
+ _malloc_printf(ASL_LEVEL_INFO, "Unknown file descriptor; expecting stack logging index file\n");
+ return -1;
+ }
+
+ // The file *should* already exist. If not, fail.
+ fd = open(file_to_reopen, O_WRONLY | O_APPEND);
+ if (fd < 3) {
+ // If we somehow got stdin/out/err, we need to relinquish them and
+ // get another fd.
+ int fds_to_close[3] = {0};
+ while (fd < 3) {
+ if (fd == -1) {
+ _malloc_printf(ASL_LEVEL_INFO, "unable to re-open stack logging file %s\n", file_to_reopen);
+ delete_log_files();
+ return -1;
+ }
+ fds_to_close[fd] = 1;
+ fd = dup(fd);
+ }
+
+ // We have an fd we like. Close the ones we opened.
+ if (fds_to_close[0]) {
+ close(0);
+ }
+ if (fds_to_close[1]) {
+ close(1);
+ }
+ if (fds_to_close[2]) {
+ close(2);
+ }
+ }
+
+ *fd_to_reset = fd;
+ written = write(fd, buf, nbyte);
+ }
+ return written;
+}
+
+static void
+flush_data(void)
+{
+ ssize_t written; // signed size_t
+ size_t remaining;
+ char *p;
+
+ if (index_file_descriptor == -1) {
+ if (create_log_file() == NULL) {
+ return;
+ }
+ }
+
+ // Write the events before the index so that hopefully the events will be on disk if the index refers to them.
+ p = pre_write_buffers->index_buffer;
+ remaining = (size_t)pre_write_buffers->next_free_index_buffer_offset;
+ while (remaining > 0) {
+ written = robust_write(index_file_descriptor, p, remaining);
+ if (written == -1) {
+ _malloc_printf(
+ ASL_LEVEL_INFO, "Unable to write to stack logging file %s (%s)\n", __stack_log_file_path__, strerror(errno));
+ disable_stack_logging();
+ return;
+ }
+ p += written;
+ remaining -= written;
+ }
+
+ pre_write_buffers->start_index_offset += pre_write_buffers->next_free_index_buffer_offset;
+ pre_write_buffers->next_free_index_buffer_offset = 0;
+}
+
+__attribute__((visibility("hidden"))) boolean_t
+__prepare_to_log_stacks(boolean_t lite_mode)
+{
+ if (!pre_write_buffers) {
+ last_logged_malloc_address = 0ul;
+ logging_use_compaction = (stack_logging_dontcompact ? 0 : logging_use_compaction);
+
+ // Create a VM region to hold the pre-write index and stack buffers. The address of this VM region will be
+ // encoded into the stack log file name, so that the stack log reading code running in remote analysis
+ // processes can find it and map it into the analysis process. This allows remote analysis processes to access
+ // these buffers to get logs for even the most recent allocations. The remote process will need to pause this
+ // process to assure that the contents of these buffers don't change while being inspected.
+ //
+ // We used to use shm_open() to create a shared memory region for this, but since this code runs in arbitrary
+ // processes that may have sandbox restrictions that don't allow the creation of shared memory regions,
+ // we're using this "create a region and put its address in the stack log file name" approach.
+ size_t full_shared_mem_size = sizeof(stack_buffer_shared_memory);
+ pre_write_buffers = mmap(
+ 0, full_shared_mem_size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, VM_MAKE_TAG(VM_MEMORY_ANALYSIS_TOOL), 0);
+ if (MAP_FAILED == pre_write_buffers) {
+ _malloc_printf(ASL_LEVEL_INFO, "error creating VM region for stack logging output buffers\n");
+ disable_stack_logging();
+ return false;
+ }
+
+ // Store and use the buffer offsets in shared memory so that they can be accessed remotely
+ pre_write_buffers->start_index_offset = 0ull;
+ pre_write_buffers->next_free_index_buffer_offset = 0;
+
+ // create the backtrace uniquing table
+ pre_write_buffers->uniquing_table = __create_uniquing_table(lite_mode);
+ if (!pre_write_buffers->uniquing_table) {
+ _malloc_printf(ASL_LEVEL_INFO, "error while allocating stack uniquing table\n");
+ disable_stack_logging();
+ return false;
+ }
+
+ pre_write_buffers->vm_stackid_table = NULL;
+
+ uint64_t stack_buffer_sz = (uint64_t)round_page(sizeof(vm_address_t) * STACK_LOGGING_MAX_STACK_SIZE);
+ stack_buffer = (vm_address_t *)sld_allocate_pages(stack_buffer_sz);
+ if (!stack_buffer) {
+ _malloc_printf(ASL_LEVEL_INFO, "error while allocating stack trace buffer\n");
+ disable_stack_logging();
+ return false;
+ }
+
+ // lite_mode doesn't use a file
+ if (lite_mode) {
+ __mach_stack_logging_shared_memory_address = (uint64_t) pre_write_buffers;
+ } else {
+ // this call ensures that the log files exist; analyzing processes will rely on this assumption.
+ if (create_log_file() == NULL) {
+ /* postponement support requires cleaning up these structures now */
+ __destroy_uniquing_table(pre_write_buffers->uniquing_table);
+ sld_deallocate_pages(stack_buffer, stack_buffer_sz);
+ stack_buffer = NULL;
+
+ munmap(pre_write_buffers, full_shared_mem_size);
+ pre_write_buffers = NULL;
+
+ if (!stack_logging_postponed) {
+ disable_stack_logging();
+ }
+ return false;
+ }
+ }
+ }
+
+ return true;
+}
+
+__attribute__((visibility("hidden"))) void
+__prepare_to_log_stacks_stage2(void)
+{
+ static int stage2done = 0;
+
+ if (!stage2done) {
+ // malloc() can be called by the following, so these need to be done outside the stack_logging_lock but after the buffers
+ // have been set up.
+ atexit(delete_log_files); // atexit() can call malloc()
+
+ // Reaping orphaned stack log files from dead processes is a nicety, to help
+ // reduce wasted disk space. But we don't *always* have to do it. Specifically,
+ // do not reap orphaned stack log files if the process name is sandboxd or taskgated,
+ // or if the MallocStackLoggingNoReaping env var is set to any value other than "no"
+ // (case-insensitive) or "0". This provides multiple ways to fix
+ // <rdar://problem/14409213> "processes hang if sandboxd is running with
+ // MallocStackLogging enabled", which happened because there were two different
+ // places down inside reap_orphaned_log_files() which called sysctl() for KERN_PROCARGS2
+ // or KERN_PROC_PID, causing iteration of the process list in the kernel, which takes
+ // a lock, which can't happen when processes are in a transitional state.
+ bool should_reap = true;
+ const char *progname = getprogname();
+ if (progname && (strcmp(progname, "sandboxd") == 0 || strcmp(progname, "taskgated") == 0)) {
+ should_reap = false;
+ }
+ if (should_reap) {
+ char *noreap = getenv("MallocStackLoggingNoReaping");
+ if (noreap && strcasecmp(noreap, "no") != 0 && strcmp(noreap, "0") != 0) {
+ should_reap = false;
+ }
+ }
+ if (should_reap) {
+ reap_orphaned_log_files(getpid(), NULL); // this calls opendir() which calls malloc()
+ }
+
+ stage2done = 1;
+ }
+}
+
+__attribute__((visibility("hidden"))) void
+__malloc_lock_stack_logging()
+{
+ _malloc_lock_lock(&stack_logging_lock);
+ thread_doing_logging = (vm_address_t)_os_tsd_get_direct(__TSD_THREAD_SELF);
+}
+
+__attribute__((visibility("hidden"))) void
+__malloc_unlock_stack_logging()
+{
+ thread_doing_logging = 0;
+ _malloc_lock_unlock(&stack_logging_lock);
+}
+
+const uint64_t __invalid_stack_id = (uint64_t)(-1ll);
+
+// returns the stack id or invalid_stack_id if any kind of error
+// this needs to be done while stack_logging_lock is locked)
+
+__attribute__((visibility("hidden"))) uint64_t
+__enter_stack_into_table_while_locked(vm_address_t self_thread, uint32_t num_hot_to_skip, boolean_t add_thread_id, size_t ptr_size)
+{
+ // gather stack
+ uint32_t count;
+ thread_stack_pcs(stack_buffer, STACK_LOGGING_MAX_STACK_SIZE - 1, &count); // only gather up to STACK_LOGGING_MAX_STACK_SIZE-1 since we append thread id
+
+ if (add_thread_id) {
+ stack_buffer[count++] = self_thread + 1; // stuffing thread # in the coldest slot. Add 1 to match what the old stack logging did.
+ }
+
+ // skip stack frames after the malloc call
+ num_hot_to_skip += 3; // __disk_stack_logging_log_stack | __enter_stack_into_table_while_locked | thread_stack_pcs
+
+ if (count <= num_hot_to_skip) {
+ // Oops! Didn't get a valid backtrace from thread_stack_pcs().
+ return __invalid_stack_id;
+ }
+
+ // unique stack in memory
+ count -= num_hot_to_skip;
+
+#if __LP64__
+ mach_vm_address_t *frames = (mach_vm_address_t*)stack_buffer + num_hot_to_skip;
+#else
+ mach_vm_address_t frames[STACK_LOGGING_MAX_STACK_SIZE];
+ uint32_t i;
+ for (i = 0; i < count; i++) {
+ frames[i] = stack_buffer[i+num_hot_to_skip];
+ }
+#endif
+
+ uint64_t uniqueStackIdentifier = __invalid_stack_id;
+
+ while (!enter_frames_in_table(pre_write_buffers->uniquing_table, &uniqueStackIdentifier, frames, count, ptr_size)) {
+ if (!__expand_uniquing_table(pre_write_buffers->uniquing_table))
+ return __invalid_stack_id;
+ }
+
+ return uniqueStackIdentifier;
+}
+
+static void
+decrement_ref_count(table_slot_t *table_slot, size_t ptr_size)
+{
+ if (table_slot->refcount_slot.refcount > 0) {
+ table_slot->refcount_slot.refcount -= ptr_size;
+
+ if (table_slot->refcount_slot.refcount == 0) {
+ table_slot->slots.slot0 = table_slot->slots.slot1 = 0;
+ }
+ }
+}
+
+__attribute__((visibility("hidden"))) void
+__decrement_table_slot_refcount(uint64_t stack_id, size_t ptr_size)
+{
+ __malloc_lock_stack_logging();
+
+ // see if msl lite was disabled behind our backs
+ if (!is_stack_logging_lite_enabled()) {
+ __malloc_unlock_stack_logging();
+ return;
+ }
+
+ backtrace_uniquing_table *uniquing_table = pre_write_buffers->uniquing_table;
+
+ assert(uniquing_table->nodes_use_refcount);
+ assert(!uniquing_table->in_client_process);
+
+ slot_parent parent = stack_id;
+ slot_parent prev_parent = __invalid_stack_id;
+
+ do {
+ if (parent == prev_parent) {
+ malloc_printf("circular parent reference in __decrement_table_slot_refcount\n");
+ break;
+ }
+
+ prev_parent = parent;
+
+ table_slot_t *table_slot = (table_slot_t *) (uniquing_table->u.table + (parent * 2));
+
+ parent = table_slot->refcount_slot.parent;
+ decrement_ref_count(table_slot, ptr_size);
+ } while (parent != slot_no_parent_refcount);
+
+ __malloc_unlock_stack_logging();
+}
+
+void
+__disk_stack_logging_log_stack(uint32_t type_flags,
+ uintptr_t zone_ptr,
+ uintptr_t arg2,
+ uintptr_t arg3,
+ uintptr_t return_val,
+ uint32_t num_hot_to_skip)
+{
+ if (!stack_logging_enable_logging || stack_logging_postponed) {
+ return;
+ }
+
+ if (stack_logging_mode == stack_logging_mode_lite &&
+ !((type_flags & stack_logging_type_vm_allocate) ||(type_flags & stack_logging_type_vm_deallocate))) {
+ return;
+ }
+
+ uintptr_t size;
+ uintptr_t ptr_arg;
+
+ // check incoming data
+ if (type_flags & stack_logging_type_alloc && type_flags & stack_logging_type_dealloc) {
+ size = arg3;
+ ptr_arg = arg2; // the original pointer
+ if (ptr_arg == return_val) {
+ return; // realloc had no effect, skipping
+ }
+ if (ptr_arg == 0) { // realloc(NULL, size) same as malloc(size)
+ type_flags ^= stack_logging_type_dealloc;
+ } else {
+ // realloc(arg1, arg2) -> result is same as free(arg1); malloc(arg2) -> result
+ __disk_stack_logging_log_stack(
+ stack_logging_type_dealloc, zone_ptr, ptr_arg, (uintptr_t)0, (uintptr_t)0, num_hot_to_skip + 1);
+ __disk_stack_logging_log_stack(stack_logging_type_alloc, zone_ptr, size, (uintptr_t)0, return_val, num_hot_to_skip + 1);
+ return;
+ }
+ }
+ if (type_flags & stack_logging_type_dealloc || type_flags & stack_logging_type_vm_deallocate) {
+ // For VM deallocations we need to know the size, since they don't always match the
+ // VM allocations. It would be nice if arg2 was the size, for consistency with alloc and
+ // realloc events. However we can't easily make that change because all projects
+ // (malloc.c, GC auto_zone, and gmalloc) have historically put the pointer in arg2 and 0 as
+ // the size in arg3. We'd need to change all those projects in lockstep, which isn't worth
+ // the trouble.
+ ptr_arg = arg2;
+ size = arg3;
+ if (ptr_arg == 0) {
+ return; // free(nil)
+ }
+ }
+ if (type_flags & stack_logging_type_alloc || type_flags & stack_logging_type_vm_allocate) {
+ if (return_val == 0 || return_val == (uintptr_t)MAP_FAILED) {
+ return; // alloc that failed
+ }
+ size = arg2;
+ }
+
+ if (type_flags & stack_logging_type_vm_allocate || type_flags & stack_logging_type_vm_deallocate) {
+ mach_port_t targetTask = (mach_port_t)zone_ptr;
+ // For now, ignore "injections" of VM into other tasks.
+ if (targetTask != mach_task_self()) {
+ return;
+ }
+ }
+
+ type_flags &= stack_logging_valid_type_flags;
+
+ vm_address_t self_thread = (vm_address_t)_os_tsd_get_direct(__TSD_THREAD_SELF);
+
+ if (thread_doing_logging == self_thread) {
+ // Prevent a thread from deadlocking against itself if vm_allocate() or malloc()
+ // is called below here, from __prepare_to_log_stacks() or _prepare_to_log_stacks_stage2(),
+ // or if we are logging an event and need to call __expand_uniquing_table() which calls
+ // vm_allocate() to grow stack logging data structures. Any such "administrative"
+ // vm_allocate or malloc calls would attempt to recursively log those events.
+ return;
+ }
+
+ // lock and enter
+ _malloc_lock_lock(&stack_logging_lock);
+
+ thread_doing_logging = self_thread; // for preventing deadlock'ing on stack logging on a single thread
+
+ if (stack_logging_mode == stack_logging_mode_lite && (type_flags & stack_logging_type_vm_deallocate)) {
+ if (pre_write_buffers && pre_write_buffers->vm_stackid_table) {
+ radix_tree_delete(&pre_write_buffers->vm_stackid_table,
+ trunc_page(ptr_arg), round_page(ptr_arg + size) - trunc_page(ptr_arg));
+ goto out;
+ }
+ }
+
+ // now actually begin
+ __prepare_to_log_stacks(false);
+
+ // since there could have been a fatal (to stack logging) error such as the log files not being created, check these variables
+ // before continuing
+ if (!stack_logging_enable_logging || stack_logging_postponed) {
+ goto out;
+ }
+
+ if (type_flags & stack_logging_type_alloc) {
+ // Only do this second stage of setup when we first record a malloc (as opposed to a VM allocation),
+ // to ensure that the malloc zone has already been created as is necessary for this.
+ __prepare_to_log_stacks_stage2();
+ }
+
+ // compaction
+ if (last_logged_malloc_address && (type_flags & stack_logging_type_dealloc) &&
+ STACK_LOGGING_DISGUISE(ptr_arg) == last_logged_malloc_address) {
+ // *waves hand* the last allocation never occurred
+ pre_write_buffers->next_free_index_buffer_offset -= (uint32_t)sizeof(stack_logging_index_event);
+ last_logged_malloc_address = 0ul;
+ goto out;
+ }
+
+ uint64_t uniqueStackIdentifier;
+ if (stack_logging_mode == stack_logging_mode_lite) {
+ uniqueStackIdentifier = __enter_stack_into_table_while_locked(self_thread, num_hot_to_skip, false, 1);
+ } else {
+ uniqueStackIdentifier = __enter_stack_into_table_while_locked(self_thread, num_hot_to_skip, true, 0);
+ }
+
+ if (uniqueStackIdentifier == __invalid_stack_id) {
+ goto out;
+ }
+
+ if (stack_logging_mode == stack_logging_mode_lite && (type_flags & stack_logging_type_vm_allocate)) {
+ if (pre_write_buffers) {
+ if (!pre_write_buffers->vm_stackid_table) {
+ pre_write_buffers->vm_stackid_table = radix_tree_create();
+ pre_write_buffers->vm_stackid_table_size = radix_tree_size(pre_write_buffers->vm_stackid_table);
+ }
+ if (pre_write_buffers->vm_stackid_table) {
+ uint64_t address = return_val;
+ radix_tree_insert(&pre_write_buffers->vm_stackid_table,
+ trunc_page(address), round_page(address+size) - trunc_page(address),
+ uniqueStackIdentifier);
+ pre_write_buffers->vm_stackid_table_size = radix_tree_size(pre_write_buffers->vm_stackid_table);
+ }
+ }
+ goto out;
+ }
+
+ stack_logging_index_event current_index;
+ if (type_flags & stack_logging_type_alloc || type_flags & stack_logging_type_vm_allocate) {
+ current_index.address = STACK_LOGGING_DISGUISE(return_val);
+ current_index.argument = size;
+ if (logging_use_compaction) {
+ last_logged_malloc_address = current_index.address; // disguised
+ }
+ } else {
+ current_index.address = STACK_LOGGING_DISGUISE(ptr_arg);
+ current_index.argument = size;
+ last_logged_malloc_address = 0ul;
+ }
+ current_index.offset_and_flags = STACK_LOGGING_OFFSET_AND_FLAGS(uniqueStackIdentifier, type_flags);
+
+ // the following line is a good debugging tool for logging each allocation event as it happens.
+ // malloc_printf("{0x%lx, %lld}\n", STACK_LOGGING_DISGUISE(current_index.address), uniqueStackIdentifier);
+
+ // flush the data buffer to disk if necessary
+ if (pre_write_buffers->next_free_index_buffer_offset + sizeof(stack_logging_index_event) >= STACK_LOGGING_BLOCK_WRITING_SIZE) {
+ flush_data();
+ }
+
+ // store bytes in buffers
+ memcpy(pre_write_buffers->index_buffer + pre_write_buffers->next_free_index_buffer_offset, ¤t_index,
+ sizeof(stack_logging_index_event));
+ pre_write_buffers->next_free_index_buffer_offset += (uint32_t)sizeof(stack_logging_index_event);
+
+out:
+ thread_doing_logging = 0;
+ _malloc_lock_unlock(&stack_logging_lock);
+}
+
+void
+__stack_logging_fork_prepare(void)
+{
+ _malloc_lock_lock(&stack_logging_lock);
+}
+
+void
+__stack_logging_fork_parent(void)
+{
+ _malloc_lock_unlock(&stack_logging_lock);
+}
+
+void
+__stack_logging_fork_child(void)
+{
+ malloc_logger = NULL;
+ stack_logging_enable_logging = 0;
+ _malloc_lock_init(&stack_logging_lock);
+}
+
+void
+__stack_logging_early_finished(void)
+{
+ stack_logging_finished_init = 1;
+ stack_logging_postponed = 0;
+}
+
+// support for gdb and others checking for stack_logging locks
+__attribute__((visibility("hidden"))) boolean_t
+__stack_logging_locked(void)
+{
+ bool acquired_lock = _malloc_lock_trylock(&stack_logging_lock);
+ if (acquired_lock) {
+ _malloc_lock_unlock(&stack_logging_lock);
+ }
+ return (acquired_lock ? false : true);
+}
+
+#pragma mark -
+#pragma mark Remote Stack Log Access
+
+#pragma mark - Design notes:
+
+/*
+ *
+ * this first one will look through the index, find the "stack_identifier" (i.e. the offset in the log file), and call the third
+ * function listed here.
+ * extern kern_return_t __mach_stack_logging_get_frames(task_t task, mach_vm_address_t address, mach_vm_address_t
+ * stack_frames_buffer, uint32_t max_stack_frames, uint32_t *num_frames);
+ * // Gets the last allocation record about address
+ *
+ * if !address, will load index and iterate through (expensive)
+ * else will load just index, search for stack, and then use third function here to retrieve. (also expensive)
+ * extern kern_return_t __mach_stack_logging_enumerate_records(task_t task, mach_vm_address_t address, void
+ * enumerator(mach_stack_logging_record_t, void *), void *context);
+ * // Applies enumerator to all records involving address sending context as enumerator's second parameter; if !address, applies
+ * enumerator to all records
+ *
+ * this function will load the stack file, look for the stack, and follow up to STACK_LOGGING_FORCE_FULL_BACKTRACE_EVERY references
+ * to
+ * reconstruct.
+ * extern kern_return_t __mach_stack_logging_frames_for_uniqued_stack(task_t task, uint64_t stack_identifier, mach_vm_address_t
+ * stack_frames_buffer, uint32_t max_stack_frames, uint32_t *count);
+ * // Given a uniqued_stack fills stack_frames_buffer
+ *
+ */
+
+#pragma mark -
+#pragma mark Backtrace Uniquing Table Reading and Lookup
+
+// This is client-side code to get a stack log from a uniquing_table.
+static void
+free_uniquing_table_chunks(backtrace_uniquing_table *uniquing_table)
+{
+ table_chunk_header_t *table_chunk_header = uniquing_table->u.first_table_chunk_hdr;
+ assert(uniquing_table->in_client_process);
+ while (table_chunk_header) {
+ mach_vm_deallocate(mach_task_self(), (mach_vm_address_t)(uintptr_t)(table_chunk_header->table_chunk),
+ table_chunk_header->table_chunk_size);
+ table_chunk_header_t *next = table_chunk_header->next_table_chunk_header;
+ free(table_chunk_header);
+ table_chunk_header = next;
+ }
+}
+
+static kern_return_t
+read_uniquing_table_from_task(task_t remote_task, backtrace_uniquing_table *uniquing_table)
+{
+ assert(uniquing_table->in_client_process);
+ mach_vm_address_t next_address_to_read = uniquing_table->table_address;
+ uint64_t remaining_size_to_read = uniquing_table->tableSize;
+ const mach_vm_size_t two_gigabytes =
+ 2ull * 1024 * 1024 * 1024; // attempting to read 4 GB in one call fails, so try a max of 2 GB
+ table_chunk_header_t **table_chunk_hdr_ptr = &(uniquing_table->u.first_table_chunk_hdr);
+ *table_chunk_hdr_ptr = NULL;
+
+ while (remaining_size_to_read > 0ull) {
+ vm_address_t local_table_chunk_address = 0ul;
+ mach_msg_type_number_t local_table_chunk_size = 0;
+
+ mach_vm_size_t next_size_to_read = (remaining_size_to_read > two_gigabytes) ? two_gigabytes : remaining_size_to_read;
+ while (1) {
+ kern_return_t err = mach_vm_read(
+ remote_task, next_address_to_read, next_size_to_read, &local_table_chunk_address, &local_table_chunk_size);
+ if (err == KERN_SUCCESS) {
+ *table_chunk_hdr_ptr = malloc(sizeof(table_chunk_header_t));
+ table_chunk_header_t *table_chunk_hdr = *table_chunk_hdr_ptr;
+ table_chunk_hdr->num_nodes_in_chunk = local_table_chunk_size / (sizeof(mach_vm_address_t) * 2);
+ ;
+ table_chunk_hdr->table_chunk = (mach_vm_address_t *)local_table_chunk_address;
+ table_chunk_hdr->table_chunk_size = local_table_chunk_size;
+ table_chunk_hdr->next_table_chunk_header = NULL; // initialize it, in case it is the last chunk
+ table_chunk_hdr_ptr = &(table_chunk_hdr->next_table_chunk_header); // set up to assign next chunk to this
+
+ next_address_to_read += local_table_chunk_size;
+ remaining_size_to_read -= local_table_chunk_size;
+ // fprintf(stderr, "requested %#qx, got %#x of %#qx at %p from backtrace uniquing table of target process\n",
+ // next_size_to_read, local_table_chunk_size, uniquing_table->tableSize, table_chunk_hdr);
+ break;
+ } else {
+ // fprintf(stderr, "requested %#qx, failed\n", next_size_to_read);
+ next_size_to_read /= 2;
+ if (next_size_to_read <= 1024 * 1024) {
+ // We couldn't even map one megabyte? Let's call that an error...
+ free_uniquing_table_chunks(uniquing_table);
+ return err;
+ }
+ }
+ }
+ }
+ return KERN_SUCCESS;
+}
+
+static mach_vm_address_t *
+get_node_from_uniquing_table(backtrace_uniquing_table *uniquing_table, uint64_t index_pos)
+{
+ assert(uniquing_table->in_client_process);
+ table_chunk_header_t *table_chunk_hdr = uniquing_table->u.first_table_chunk_hdr;
+ uint64_t start_node_of_chunk = 0;
+ while (table_chunk_hdr && index_pos > start_node_of_chunk + table_chunk_hdr->num_nodes_in_chunk) {
+ table_chunk_hdr = table_chunk_hdr->next_table_chunk_header;
+ if (table_chunk_hdr) {
+ start_node_of_chunk += table_chunk_hdr->num_nodes_in_chunk;
+ }
+ }
+
+ // Handle case where someone passes an invalid stack id
+ // <rdar://problem/25337823> get_node_from_uniquing_table should be more tolerant
+ if (!table_chunk_hdr) {
+ return NULL;
+ }
+
+ uint64_t index_in_chunk = index_pos - start_node_of_chunk;
+ mach_vm_address_t *node = table_chunk_hdr->table_chunk + (index_in_chunk * 2);
+ return node;
+}
+
+static void
+unwind_stack_from_table_index(backtrace_uniquing_table *uniquing_table,
+ uint64_t index_pos,
+ mach_vm_address_t *out_frames_buffer,
+ uint32_t *out_frames_count,
+ uint32_t max_frames,
+ boolean_t use_refcount)
+{
+ mach_vm_address_t *node = get_node_from_uniquing_table(uniquing_table, index_pos);
+ uint32_t foundFrames = 0;
+ slot_parent end_parent = use_refcount ? slot_no_parent_refcount : slot_no_parent_normal;
+
+ if (node && index_pos < uniquing_table->numNodes) {
+ while (foundFrames < max_frames) {
+ table_slot_t *table_slot = (table_slot_t *) (node);
+
+ slot_address address = use_refcount ? table_slot->refcount_slot.address : table_slot->normal_slot.address;
+
+ out_frames_buffer[foundFrames++] = address;
+
+ if (use_refcount && table_slot->refcount_slot.refcount == 0) {
+ break;
+ }
+
+ slot_parent parent = use_refcount ? table_slot->refcount_slot.parent : table_slot->normal_slot.parent;
+
+ if (parent == end_parent) {
+ break;
+ }
+
+ node = get_node_from_uniquing_table(uniquing_table, parent);
+ }
+ }
+
+ *out_frames_count = foundFrames;
+}
+
+#pragma mark - caching
+
+__attribute__((always_inline)) static inline size_t
+hash_index(uint64_t address, size_t max_pos)
+{
+ return (size_t)((address >> 2) % (max_pos - 1)); // simplicity rules.
+}
+
+__attribute__((always_inline)) static inline size_t
+hash_multiplier(size_t capacity, uint32_t allowed_collisions)
+{
+ return (capacity / (allowed_collisions * 2 + 1));
+}
+
+__attribute__((always_inline)) static inline size_t
+next_hash(size_t hash, size_t multiplier, size_t capacity, uint32_t collisions)
+{
+ hash += multiplier * collisions;
+ if (hash >= capacity) {
+ hash -= capacity;
+ }
+ return hash;
+}
+
+static void
+transfer_node(remote_index_cache *cache, remote_index_node *old_node)
+{
+ uint32_t collisions = 0;
+ size_t pos = hash_index(old_node->address, cache->cache_node_capacity);
+ size_t multiplier = hash_multiplier(cache->cache_node_capacity, cache->collision_allowance);
+ do {
+ if (cache->table_memory[pos].address == old_node->address) { // hit like this shouldn't happen.
+ fprintf(stderr, "impossible collision! two address==address lists! (transfer_node)\n");
+ break;
+ } else if (cache->table_memory[pos].address == 0) { // empty
+ cache->table_memory[pos] = *old_node;
+ break;
+ } else {
+ collisions++;
+ pos = next_hash(pos, multiplier, cache->cache_node_capacity, collisions);
+ }
+ } while (collisions <= cache->collision_allowance);
+
+ if (collisions > cache->collision_allowance) {
+ fprintf(stderr, "reporting bad hash function! disk stack logging reader %lu bit. (transfer_node)\n", sizeof(void *) * 8);
+ }
+}
+
+static void
+expand_cache(remote_index_cache *cache)
+{
+ // keep old stats
+ size_t old_node_capacity = cache->cache_node_capacity;
+ remote_index_node *old_table = cache->table_memory;
+
+ // double size
+ cache->cache_size <<= 2;
+ cache->cache_node_capacity <<= 2;
+ cache->collision_allowance += 3;
+ cache->table_memory = (void *)calloc(cache->cache_node_capacity, sizeof(remote_index_node));
+
+ // repopulate (expensive!)
+ size_t i;
+ for (i = 0; i < old_node_capacity; i++) {
+ if (old_table[i].address) {
+ transfer_node(cache, &old_table[i]);
+ }
+ }
+ free(old_table);
+ // printf("cache expanded to %0.2f mb (eff: %3.0f%%, capacity: %lu, nodes: %llu, llnodes: %llu)\n",
+ //((float)(cache->cache_size))/(1 << 20), ((float)(cache->cache_node_count)*100.0)/((float)(cache->cache_node_capacity)),
+ // cache->cache_node_capacity, cache->cache_node_count, cache->cache_llnode_count);
+}
+
+static void
+insert_node(remote_index_cache *cache, uint64_t address, uint64_t index_file_offset)
+{
+ uint32_t collisions = 0;
+ size_t pos = hash_index(address, cache->cache_node_capacity);
+ size_t multiplier = hash_multiplier(cache->cache_node_capacity, cache->collision_allowance);
+
+ while (1) {
+ if (cache->table_memory[pos].address == 0ull || cache->table_memory[pos].address == address) { // hit or empty
+ cache->table_memory[pos].address = address;
+ cache->table_memory[pos].index_file_offset = index_file_offset;
+ // Inserted it! Break out of the loop.
+ break;
+ }
+
+ collisions++;
+ pos = next_hash(pos, multiplier, cache->cache_node_capacity, collisions);
+
+ if (collisions > cache->collision_allowance) {
+ expand_cache(cache);
+ pos = hash_index(address, cache->cache_node_capacity);
+ multiplier = hash_multiplier(cache->cache_node_capacity, cache->collision_allowance);
+ collisions = 0;
+ }
+ }
+}
+
+// Kudos to Daniel Delwood for this function. This is called in an analysis tool process
+// to share a VM region from a target process, without the target process needing to explicitly
+// share the region itself via shm_open(). The VM_FLAGS_RETURN_DATA_ADDR flag is necessary
+// for iOS in case the target process uses a different VM page size than the analysis tool process.
+static mach_vm_address_t
+map_shared_memory_from_task(task_t sourceTask, mach_vm_address_t sourceAddress, mach_vm_size_t sourceSize)
+{
+#if TARGET_OS_EMBEDDED
+ int mapRequestFlags = VM_FLAGS_ANYWHERE | VM_FLAGS_RETURN_DATA_ADDR;
+ mach_vm_address_t mapRequestAddress = sourceAddress;
+ mach_vm_size_t mapRequestSize = sourceSize;
+#else
+ // Sadly, VM_FLAGS_RETURN_DATA_ADDR isn't available to us; align everything manually.
+ int mapRequestFlags = VM_FLAGS_ANYWHERE;
+ mach_vm_address_t mapRequestAddress = trunc_page(sourceAddress);
+ mach_vm_size_t mapRequestSize = round_page(sourceAddress + sourceSize) - mapRequestAddress;
+#endif
+ mach_vm_address_t mappedAddress = 0;
+ vm_prot_t outCurrentProt = VM_PROT_NONE;
+ vm_prot_t outMaxProt = VM_PROT_NONE;
+ kern_return_t err = mach_vm_remap(mach_task_self(), &mappedAddress, mapRequestSize, 0, mapRequestFlags, sourceTask,
+ mapRequestAddress, false, &outCurrentProt, &outMaxProt, VM_INHERIT_NONE);
+ if (err != KERN_SUCCESS) {
+ return 0;
+ }
+ return mappedAddress + (sourceAddress - mapRequestAddress);
+}
+
+static kern_return_t
+update_cache_for_file_streams(remote_task_file_streams *descriptors)
+{
+ remote_index_cache *cache = descriptors->cache;
+
+ // create from scratch if necessary.
+ if (!cache) {
+ descriptors->cache = cache = (remote_index_cache *)calloc((size_t)1, sizeof(remote_index_cache));
+ cache->cache_node_capacity = 1 << 14;
+ cache->collision_allowance = 17;
+ cache->last_index_file_offset = 0;
+ cache->cache_size = cache->cache_node_capacity * sizeof(remote_index_node);
+ cache->table_memory = (void *)calloc(cache->cache_node_capacity, sizeof(remote_index_node));
+
+ cache->shmem = (stack_buffer_shared_memory *)map_shared_memory_from_task(descriptors->remote_task,
+ descriptors->remote_stack_buffer_shared_memory_address, sizeof(stack_buffer_shared_memory));
+ if (!cache->shmem) {
+ // failed to connect to the shared memory region; warn and continue.
+ _malloc_printf(ASL_LEVEL_INFO,
+ "warning: unable to map shared memory from %llx in target process %d; no stack backtraces will be available.\n",
+ descriptors->remote_stack_buffer_shared_memory_address, descriptors->remote_pid);
+ }
+ cache->lite_mode = descriptors->task_uses_lite_mode;
+
+ if (cache->shmem && cache->shmem->vm_stackid_table) {
+ cache->vm_stackid_table = (struct radix_tree *)map_shared_memory_from_task(
+ descriptors->remote_task, (mach_vm_address_t) cache->shmem->vm_stackid_table, cache->shmem->vm_stackid_table_size);
+ if (!cache->vm_stackid_table) {
+ _malloc_printf(ASL_LEVEL_INFO,
+ "warning: unable to map vm_stackid table from %llx in target process %d; no VM stack backtraces will be available.\n",
+ (mach_vm_address_t) cache->shmem->vm_stackid_table, descriptors->remote_pid);
+ }
+ }
+ }
+
+ // suspend and see how much updating there is to do. there are three scenarios, listed below
+ bool update_snapshot = false;
+ if (descriptors->remote_task != mach_task_self()) {
+ task_suspend(descriptors->remote_task);
+ }
+
+ struct stat file_statistics;
+
+ if (descriptors->index_file_stream) {
+ fstat(fileno(descriptors->index_file_stream), &file_statistics);
+ } else {
+ file_statistics.st_size = 0;
+ }
+
+ size_t read_size = (descriptors->task_is_64_bit ? sizeof(stack_logging_index_event64) : sizeof(stack_logging_index_event32));
+ uint64_t read_this_update = 0;
+
+ // the delta indecies is a complex number; there are three cases:
+ // 1. there is no shared memory (or we can't connect); diff the last_index_file_offset from the filesize.
+ // 2. the only updates have been in shared memory; disk file didn't change at all. delta_indecies should be zero, scan snapshot
+ // only.
+ // 3. the updates have flushed to disk, meaning that most likely there is new data on disk that wasn't read from shared memory.
+ // correct delta_indecies for the pre-scanned amount and read the new data from disk and shmem.
+ uint64_t delta_indecies = (file_statistics.st_size - cache->last_index_file_offset) / read_size;
+ uint32_t last_snapshot_scan_index = 0;
+ if (delta_indecies && cache->shmem) {
+ // case 3: add cache scanned to known from disk and recalc
+ cache->last_index_file_offset += cache->snapshot.next_free_index_buffer_offset;
+ delta_indecies = (file_statistics.st_size - cache->last_index_file_offset) / read_size;
+ update_snapshot = true;
+ } else if (cache->shmem) {
+ // case 2: set the last snapshot scan count so we don't rescan something we've seen.
+ last_snapshot_scan_index = cache->snapshot.next_free_index_buffer_offset / (uint32_t)read_size;
+ }
+
+ // no update necessary for the file; check if need a snapshot.
+ if (delta_indecies == 0) {
+ if (cache->shmem && !update_snapshot) {
+ update_snapshot = (cache->shmem->next_free_index_buffer_offset != cache->snapshot.next_free_index_buffer_offset);
+ }
+ }
+
+ // need to update the snapshot if in lite mode and haven't yet read the uniquing table
+ if (descriptors->task_uses_lite_mode && cache->uniquing_table_snapshot.numPages == 0) {
+ update_snapshot = true;
+ }
+
+ // if a snapshot is necessary, memcpy from remote frozen process' memory
+ // note: there were two ways to do this - spin lock or suspend. suspend allows us to
+ // analyze processes even if they were artificially suspended. with a lock, there'd be
+ // worry that the target was suspended with the lock taken.
+ kern_return_t err = KERN_SUCCESS;
+ if (update_snapshot) {
+ memcpy(&cache->snapshot, cache->shmem, sizeof(stack_buffer_shared_memory));
+ // also need to update our version of the remote uniquing table
+ vm_address_t local_uniquing_address = 0ul;
+ mach_msg_type_number_t local_uniquing_size = 0;
+ mach_vm_size_t desired_size = round_page(sizeof(backtrace_uniquing_table));
+ if ((err = mach_vm_read(descriptors->remote_task, (mach_vm_address_t)cache->shmem->uniquing_table, desired_size,
+ &local_uniquing_address, &local_uniquing_size)) != KERN_SUCCESS ||
+ local_uniquing_size != desired_size) {
+ fprintf(stderr, "error while attempting to mach_vm_read remote stack uniquing table (%d): %s\n", err,
+ mach_error_string(err));
+ } else {
+ // the mach_vm_read was successful, so acquire the uniquing table
+
+ // need to re-read the table, so deallocate the current memory
+ cache->uniquing_table_snapshot.in_client_process = true;
+ free_uniquing_table_chunks(&cache->uniquing_table_snapshot);
+
+ // The following line copies the uniquing table structure data, but the actual uniquing table memory is invalid
+ // since it's a pointer from the remote process.
+ cache->uniquing_table_snapshot = *((backtrace_uniquing_table *)local_uniquing_address);
+ cache->uniquing_table_snapshot.nodes_use_refcount = cache->lite_mode;
+ cache->uniquing_table_snapshot.u.first_table_chunk_hdr = NULL;
+ cache->uniquing_table_snapshot.in_client_process = true;
+
+
+ // Read the uniquing table memory from the target process.
+ err = read_uniquing_table_from_task(descriptors->remote_task, &(cache->uniquing_table_snapshot));
+ if (err) {
+ fprintf(stderr, "error while attempting to mach_vm_read remote stack uniquing table contents (%d): %s\n", err,
+ mach_error_string(err));
+ }
+ // Check the error status below, after further deallocating and resuming the target task.
+
+ mach_vm_deallocate(mach_task_self(), (mach_vm_address_t)local_uniquing_address, (mach_vm_size_t)local_uniquing_size);
+ }
+ }
+
+ // resume
+ if (descriptors->remote_task != mach_task_self()) {
+ task_resume(descriptors->remote_task);
+ }
+
+ if (err != KERN_SUCCESS) {
+ // To Do: further clean up allocated resources, and also try to prevent printing numerous identical "out of memory" errors
+ // (maybe we should abort?).
+ return err;
+ }
+
+ if (!update_snapshot && delta_indecies == 0) {
+ return KERN_SUCCESS; // absolutely no updating needed.
+ }
+ FILE *the_index = (descriptors->index_file_stream);
+
+ // prepare for the read; target process could be 32 or 64 bit.
+
+ stack_logging_index_event32 *target_32_index = NULL;
+ stack_logging_index_event64 *target_64_index = NULL;
+
+ // perform the update from the file
+ uint32_t i;
+ if (delta_indecies) {
+ char bufferSpace[4096]; // 4 kb
+ target_32_index = (stack_logging_index_event32 *)bufferSpace;
+ target_64_index = (stack_logging_index_event64 *)bufferSpace;
+ size_t number_slots = (size_t)(4096 / read_size);
+
+ size_t read_count = 0;
+ if (fseeko(the_index, (off_t)(cache->last_index_file_offset), SEEK_SET)) {
+ fprintf(stderr,
+ "error while attempting to cache information from remote stack index file. (update_cache_for_file_streams)\n");
+ }
+ off_t current_index_position = cache->last_index_file_offset;
+ do {
+ number_slots = (size_t)MIN(delta_indecies - read_this_update, number_slots);
+ read_count = fread(bufferSpace, read_size, number_slots, the_index);
+ if (descriptors->task_is_64_bit) {
+ for (i = 0; i < read_count; i++) {
+ insert_node(cache, STACK_LOGGING_DISGUISE(target_64_index[i].address), (uint64_t)current_index_position);
+ read_this_update++;
+ current_index_position += read_size;
+ }
+ } else {
+ for (i = 0; i < read_count; i++) {
+ insert_node(cache, (mach_vm_address_t)STACK_LOGGING_DISGUISE(target_32_index[i].address),
+ (uint64_t)current_index_position);
+ read_this_update++;
+ current_index_position += read_size;
+ }
+ }
+ } while (read_count);
+
+ if (read_this_update < delta_indecies) {
+ fprintf(stderr, "insufficient data in remote stack index file; expected more records.\n");
+ }
+ cache->last_index_file_offset += read_this_update * read_size;
+ }
+
+ if (update_snapshot) {
+ target_32_index = (stack_logging_index_event32 *)(cache->snapshot.index_buffer);
+ target_64_index = (stack_logging_index_event64 *)(cache->snapshot.index_buffer);
+
+ uint32_t free_snapshot_scan_index = cache->snapshot.next_free_index_buffer_offset / (uint32_t)read_size;
+ off_t current_index_position = cache->snapshot.start_index_offset;
+ if (descriptors->task_is_64_bit) {
+ for (i = last_snapshot_scan_index; i < free_snapshot_scan_index; i++) {
+ insert_node(cache, STACK_LOGGING_DISGUISE(target_64_index[i].address),
+ (uint64_t)(current_index_position + (i * read_size)));
+ }
+ } else {
+ for (i = last_snapshot_scan_index; i < free_snapshot_scan_index; i++) {
+ insert_node(cache, (mach_vm_address_t)STACK_LOGGING_DISGUISE(target_32_index[i].address),
+ (uint64_t)(current_index_position + (i * read_size)));
+ }
+ }
+ }
+
+ return KERN_SUCCESS;
+}
+
+static void
+destroy_cache_for_file_streams(remote_task_file_streams *descriptors)
+{
+ if (!descriptors->cache) {
+ return;
+ }
+ if (descriptors->cache->shmem) {
+ munmap(descriptors->cache->shmem, sizeof(stack_buffer_shared_memory));
+ }
+ free(descriptors->cache->table_memory);
+ free_uniquing_table_chunks(&descriptors->cache->uniquing_table_snapshot);
+ free(descriptors->cache);
+ descriptors->cache = NULL;
+}
+
+#pragma mark - internal
+
+static FILE *
+open_log_file_at_path(char *pathname, remote_task_file_streams *streams) {
+ FILE *file = fopen(pathname, "r");
+ if (!file) {
+ return NULL;
+ }
+
+ char *log_file_name = strrchr(pathname, '/');
+ char *p = log_file_name;
+
+ // File names are of the form stack-logs.<pid>.<address>.<progname>.XXXXXX.index
+ if (p) p = strchr(p, '.'); // skip past "stack-logs"
+ if (p) p = strchr(p + 1, '.'); // skip past ".<pid>"
+ if (p) p++; // skip past '.'
+
+ if (!p) {
+ return NULL;
+ }
+
+ char *shared_memory_address_string = p;
+
+ // The hex address of the remote_index_cache in the target process
+ // is given in the stack log file name, following the pid and a period.
+ streams->remote_stack_buffer_shared_memory_address = strtoll(shared_memory_address_string, NULL, 16);
+ streams->index_file_stream = file;
+
+ return file;
+}
+
+// In the stack log analysis process, find the stack logging file for target process <pid>
+// by scanning the given directory for entries with names of the form "stack-logs.<pid>.*.index"
+// If we find such an entry then open that stack logging file.
+static FILE *
+open_log_file_from_directory(pid_t pid, char *directory, remote_task_file_streams *streams)
+{
+ DIR *dp;
+ struct dirent *entry;
+ char prefix_and_pid[PATH_MAX];
+ char pathname[PATH_MAX];
+ FILE *file = NULL;
+
+ // Check for access permissions in case we're sandbox'ed.
+ if (access(directory, R_OK | X_OK) == 0 && (dp = opendir(directory)) != NULL) {
+ // It's OK to use snprintf in this routine since it should only be called by the clients
+ // of stack logging, and thus calls to malloc are OK.
+ snprintf(prefix_and_pid, (size_t)PATH_MAX, "%s%d.", stack_log_file_base_name,
+ pid); // make sure to use "%s%d." rather than just "%s%d" to match the whole pid
+ size_t prefix_and_pid_length = strlen(prefix_and_pid);
+
+ while ((entry = readdir(dp)) != NULL) {
+ if (strncmp(entry->d_name, prefix_and_pid, prefix_and_pid_length) == 0) {
+ snprintf(pathname, (size_t)PATH_MAX, "%s/%s", directory, entry->d_name);
+ file = open_log_file_at_path(pathname, streams);
+ break;
+ }
+ }
+ closedir(dp);
+ }
+
+ return file;
+}
+
+// Read the launch data of the target process from the kernel to find the
+// value of the environment variable named env_var_name. Since this function
+// uses alloca() to temporarily allocate space for data copied from the kernel,
+// and we don't want to malloc space so that this can be called from malloc stack
+// logging code in the target process as well, we copy the result into the
+// env_var_value_buf of length max_path_len supplied by the caller.
+static bool
+getenv_from_process(pid_t pid, char *env_var_name, char *env_var_value_buf, size_t buf_length)
+{
+ env_var_value_buf[0] = '\0';
+
+ // Just call getenv() if pid is the current process, partly to avoid the sysctl()
+ // call which can cause system deadlock (<rdar://problem/14409213> "processes hang
+ // if sandboxd is running with MallocStackLogging enabled"). But it probably
+ // doesn't completely fix that since there is another sysctl() call in is_process_running()
+ // when checking to see if the process corresponding to an existing stack log file
+ // is still running.
+ if (pid == getpid()) {
+ char *env_var_value = getenv(env_var_name);
+ if (!env_var_value) {
+ return false;
+ } else {
+ strlcpy(env_var_value_buf, env_var_value, buf_length);
+ return true;
+ }
+ }
+
+ int mib[3];
+ size_t argbufSize = 0; // Must initialize this to 0 so this works when compiled for x86_64.
+
+ // First get the maximum arguments size, to determine the necessary buffer size.
+ mib[0] = CTL_KERN;
+ mib[1] = KERN_ARGMAX;
+
+ size_t size = sizeof(argbufSize);
+ int ret = sysctl(mib, 2, &argbufSize, &size, NULL, 0);
+ if (ret != 0) {
+ return false;
+ }
+
+ mib[0] = CTL_KERN;
+ mib[1] = KERN_PROCARGS2; // The older KERN_PROCARGS is deprecated.
+ mib[2] = pid;
+
+ char *argbuf = (char *)alloca(argbufSize);
+ ret = sysctl(mib, 3, argbuf, &argbufSize, (void *)NULL, 0);
+ if (ret != 0) {
+ return false;
+ }
+ argbuf[argbufSize - 1] = '\0'; // make sure the buffer is null-terminated
+ char *p = argbuf;
+ char *endp = &argbuf[argbufSize];
+
+ // Skip over argc, which is always 4 bytes long (int-sized), even in 64-bit architectures.
+ int argumentCount = *((int *)argbuf);
+ p += sizeof(argumentCount);
+
+ // Skip over arguments, using the argumentCount read from the start of argbuf.
+ argumentCount++; // increment argumentCount to also skip saved exec path, which comes first
+ for (int argumentNum = 0; argumentNum < argumentCount && p < endp; argumentNum++) {
+ while (p < endp && *p != '\0')
+ p++;
+ while (p < endp && *p == '\0')
+ p++; // saved exec path sometimes has multiple nul's
+ }
+
+ size_t env_var_name_length = strlen(env_var_name);
+
+ // Examine environment variables.
+ while ((p + env_var_name_length + 1) < endp && *p != '\0') {
+ if (strncmp(p, env_var_name, env_var_name_length) == 0 && p[env_var_name_length] == '=') {
+ p += env_var_name_length + 1;
+ strlcpy(env_var_value_buf, p, buf_length);
+ //_malloc_printf(ASL_LEVEL_INFO, "found env var %s='%s'\n", env_var_name, env_var_value_buf);
+ return true;
+ }
+ while (p < endp && *p != '\0')
+ p++;
+ p++;
+ }
+ return false;
+}
+
+static FILE *
+open_log_file(pid_t target_pid, remote_task_file_streams *streams)
+{
+ static bool already_reaped = false;
+ if (!already_reaped) {
+ // reap any left-over log files (for non-existent processes, but not for this analysis process)
+ reap_orphaned_log_files(target_pid, streams);
+ already_reaped = true;
+ }
+
+ if (streams->index_file_stream != NULL) { // reap_orphaned_log_files opened the file
+ return streams->index_file_stream;
+ }
+
+ // Since we're searching for the log file here, not creating it, we can search in any order we want.
+ // So look at MallocStackLoggingDirectory last since that is almost never set.
+ FILE *file = open_log_file_from_directory(target_pid, _PATH_TMP, streams);
+ if (!file) {
+ char *env_var_names[] = {"TMPDIR", "MallocStackLoggingDirectory"};
+ for (unsigned i = 0; i < sizeof(env_var_names) / sizeof(char *); i++) {
+ char directory[PATH_MAX];
+ bool success = getenv_from_process(target_pid, env_var_names[i], directory, sizeof(directory));
+ if (success) {
+ file = open_log_file_from_directory(target_pid, directory, streams);
+ if (file) {
+ break;
+ }
+ }
+ }
+ }
+ return file;
+}
+
+// shared_memory_address is non-zero when in lite mode and this is called for the first time on a task
+static remote_task_file_streams *
+retain_file_streams_for_task(task_t task, vm_address_t shared_memory_address)
+{
+ if (task == MACH_PORT_NULL) {
+ return NULL;
+ }
+
+ _malloc_lock_lock(&remote_fd_list_lock);
+
+ // see if they're already in use
+ uint32_t i = 0;
+ for (i = 0; i < remote_task_fd_count; i++) {
+ if (remote_fds[i].remote_task == task) {
+ remote_fds[i].in_use_count++;
+ _malloc_lock_unlock(&remote_fd_list_lock);
+ return &remote_fds[i];
+ }
+ }
+
+ // open them
+ uint32_t failures = 0;
+ if (remote_task_fd_count == STACK_LOGGING_MAX_SIMUL_REMOTE_TASKS_INSPECTED) {
+ while (remote_fds[next_remote_task_fd].in_use_count > 0) {
+ next_remote_task_fd++;
+ if (next_remote_task_fd == STACK_LOGGING_MAX_SIMUL_REMOTE_TASKS_INSPECTED) {
+ next_remote_task_fd = 0;
+ }
+ failures++;
+ if (failures >= STACK_LOGGING_MAX_SIMUL_REMOTE_TASKS_INSPECTED) {
+ _malloc_lock_unlock(&remote_fd_list_lock);
+ return NULL;
+ }
+ }
+ fclose(remote_fds[next_remote_task_fd].index_file_stream);
+ destroy_cache_for_file_streams(&remote_fds[next_remote_task_fd]);
+ }
+
+ pid_t pid;
+ kern_return_t err = pid_for_task(task, &pid);
+ if (err != KERN_SUCCESS) {
+ _malloc_lock_unlock(&remote_fd_list_lock);
+ return NULL;
+ }
+
+ remote_task_file_streams *this_task_streams = &remote_fds[next_remote_task_fd];
+
+ if (shared_memory_address != 0) {
+ this_task_streams->remote_stack_buffer_shared_memory_address = shared_memory_address;
+ this_task_streams->task_uses_lite_mode = true;
+ } else {
+ open_log_file(pid, this_task_streams);
+
+ if (this_task_streams->index_file_stream == NULL) {
+ _malloc_lock_unlock(&remote_fd_list_lock);
+ return NULL;
+ }
+ }
+
+ // check if target pid is running 64-bit
+ int mib[] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
+ struct kinfo_proc processInfo;
+ size_t bufsize = sizeof(processInfo);
+ if (sysctl(mib, (unsigned)(sizeof(mib) / sizeof(int)), &processInfo, &bufsize, NULL, (size_t)0) == 0 && bufsize > 0) {
+ this_task_streams->task_is_64_bit = processInfo.kp_proc.p_flag & P_LP64;
+ } else {
+ this_task_streams->task_is_64_bit = 0;
+ }
+
+ // otherwise set vars and go
+ this_task_streams->in_use_count = 1;
+ this_task_streams->remote_task = task;
+ this_task_streams->remote_pid = pid;
+ next_remote_task_fd++;
+ if (next_remote_task_fd == STACK_LOGGING_MAX_SIMUL_REMOTE_TASKS_INSPECTED) {
+ next_remote_task_fd = 0;
+ }
+ remote_task_fd_count = MIN(remote_task_fd_count + 1, STACK_LOGGING_MAX_SIMUL_REMOTE_TASKS_INSPECTED);
+
+ _malloc_lock_unlock(&remote_fd_list_lock);
+ return this_task_streams;
+}
+
+static void
+release_file_streams_for_task(task_t task)
+{
+ _malloc_lock_lock(&remote_fd_list_lock);
+
+ // decrement in-use count
+ uint32_t i = 0;
+ for (i = 0; i < remote_task_fd_count; i++) {
+ if (remote_fds[i].remote_task == task) {
+ remote_fds[i].in_use_count--;
+ break;
+ }
+ }
+
+ _malloc_lock_unlock(&remote_fd_list_lock);
+}
+
+#pragma mark - extern
+
+kern_return_t
+__mach_stack_logging_start_reading(task_t task, vm_address_t shared_memory_address, boolean_t *uses_lite_mode)
+{
+ remote_task_file_streams *remote_fd = retain_file_streams_for_task(task, shared_memory_address);
+ if (remote_fd == NULL) {
+ return KERN_FAILURE;
+ }
+
+ *uses_lite_mode = remote_fd->task_uses_lite_mode;
+
+ return KERN_SUCCESS;
+}
+
+kern_return_t
+__mach_stack_logging_stop_reading(task_t task)
+{
+ kern_return_t err = KERN_SUCCESS;
+
+ release_file_streams_for_task(task);
+
+ _malloc_lock_lock(&remote_fd_list_lock);
+
+ for (uint32_t i = 0; i < remote_task_fd_count; i++) {
+ if (remote_fds[i].remote_task == task) {
+ if (remote_fds[i].in_use_count > 0) {
+ // Hmm... the client is in the middle of a stack log reading call?
+ err = KERN_FAILURE;
+ } else {
+ // remote_fds[i].in_use_count is 0 so don't decrement it!
+ fclose(remote_fds[i].index_file_stream);
+ remote_fds[i].index_file_stream = NULL;
+ destroy_cache_for_file_streams(&remote_fds[i]);
+ remote_fds[i].remote_task = 0;
+ }
+ break;
+ }
+ }
+
+ _malloc_lock_unlock(&remote_fd_list_lock);
+
+ return err;
+}
+
+// This function is no longer used. It was a hack that required an analysis tool process
+// to read the target tasks's __stack_log_file_path__ variable then pass the value of
+// that to this function. This is now handled automatically all within this file, by
+// having the stack log reading code read the environment variables of the target process.
+// This function should be removed once no clients are calling it.
+kern_return_t
+__mach_stack_logging_set_file_path(task_t task, char *file_path)
+{
+ return KERN_SUCCESS;
+}
+
+kern_return_t
+__mach_stack_logging_get_frames(task_t task,
+ mach_vm_address_t address,
+ mach_vm_address_t *stack_frames_buffer,
+ uint32_t max_stack_frames,
+ uint32_t *count)
+{
+ remote_task_file_streams *remote_fd = retain_file_streams_for_task(task, 0);
+ if (remote_fd == NULL) {
+ return KERN_FAILURE;
+ }
+
+ kern_return_t err = update_cache_for_file_streams(remote_fd);
+ if (err != KERN_SUCCESS) {
+ release_file_streams_for_task(task);
+ return err;
+ }
+
+ uint32_t collisions = 0;
+ size_t hash = hash_index(address, remote_fd->cache->cache_node_capacity);
+ size_t multiplier = hash_multiplier(remote_fd->cache->cache_node_capacity, remote_fd->cache->collision_allowance);
+ uint64_t located_file_position = 0;
+
+ bool found = false;
+ do {
+ if (remote_fd->cache->table_memory[hash].address == address) { // hit!
+ located_file_position = remote_fd->cache->table_memory[hash].index_file_offset;
+ found = true;
+ break;
+ } else if (remote_fd->cache->table_memory[hash].address == 0ull) { // failure!
+ break;
+ }
+
+ collisions++;
+ hash = next_hash(hash, multiplier, remote_fd->cache->cache_node_capacity, collisions);
+
+ } while (collisions <= remote_fd->cache->collision_allowance);
+
+ if (found) {
+ // prepare for the read; target process could be 32 or 64 bit.
+ stack_logging_index_event32 *target_32_index = NULL;
+ stack_logging_index_event64 *target_64_index = NULL;
+
+ if (located_file_position >= remote_fd->cache->last_index_file_offset) {
+ // must be in shared memory
+ if (remote_fd->cache->shmem) {
+ if (remote_fd->task_is_64_bit) {
+ target_64_index = (stack_logging_index_event64 *)(remote_fd->cache->snapshot.index_buffer +
+ (located_file_position -
+ remote_fd->cache->snapshot.start_index_offset));
+ located_file_position = STACK_LOGGING_OFFSET(target_64_index->offset_and_flags);
+ } else {
+ target_32_index = (stack_logging_index_event32 *)(remote_fd->cache->snapshot.index_buffer +
+ (located_file_position -
+ remote_fd->cache->snapshot.start_index_offset));
+ located_file_position = STACK_LOGGING_OFFSET(target_32_index->offset_and_flags);
+ }
+ } else {
+ found = false;
+ }
+
+ } else {
+ // it's written to disk
+ char bufferSpace[128];
+
+ size_t read_size =
+ (remote_fd->task_is_64_bit ? sizeof(stack_logging_index_event64) : sizeof(stack_logging_index_event32));
+ fseeko(remote_fd->index_file_stream, (off_t)located_file_position, SEEK_SET);
+ size_t read_count = fread(bufferSpace, read_size, (size_t)1, remote_fd->index_file_stream);
+ if (read_count) {
+ if (remote_fd->task_is_64_bit) {
+ target_64_index = (stack_logging_index_event64 *)bufferSpace;
+ located_file_position = STACK_LOGGING_OFFSET(target_64_index->offset_and_flags);
+ } else {
+ target_32_index = (stack_logging_index_event32 *)bufferSpace;
+ located_file_position = STACK_LOGGING_OFFSET(target_32_index->offset_and_flags);
+ }
+ } else {
+ found = false;
+ }
+ }
+ }
+
+ release_file_streams_for_task(task);
+
+ if (!found) {
+ return KERN_FAILURE;
+ }
+
+ return __mach_stack_logging_get_frames_for_stackid(task, located_file_position, stack_frames_buffer, max_stack_frames, count, NULL);
+}
+
+kern_return_t
+__mach_stack_logging_enumerate_records(task_t task,
+ mach_vm_address_t address,
+ void enumerator(mach_stack_logging_record_t, void *),
+ void *context)
+{
+ remote_task_file_streams *remote_fd = retain_file_streams_for_task(task, 0);
+ if (remote_fd == NULL) {
+ return KERN_FAILURE;
+ }
+
+ bool reading_all_addresses = (address == 0 ? true : false);
+ mach_stack_logging_record_t pass_record;
+ kern_return_t err = KERN_SUCCESS;
+
+ // update (read index file once and only once)
+ err = update_cache_for_file_streams(remote_fd);
+ if (err != KERN_SUCCESS) {
+ release_file_streams_for_task(task);
+ return err;
+ }
+
+ FILE *the_index = (remote_fd->index_file_stream);
+
+ // prepare for the read; target process could be 32 or 64 bit.
+ char bufferSpace[2048]; // 2 kb
+ stack_logging_index_event32 *target_32_index = (stack_logging_index_event32 *)bufferSpace;
+ stack_logging_index_event64 *target_64_index = (stack_logging_index_event64 *)bufferSpace;
+ uint32_t target_addr_32 = (uint32_t)STACK_LOGGING_DISGUISE((uint32_t)address);
+ uint64_t target_addr_64 = STACK_LOGGING_DISGUISE((uint64_t)address);
+ size_t read_size = (remote_fd->task_is_64_bit ? sizeof(stack_logging_index_event64) : sizeof(stack_logging_index_event32));
+ size_t number_slots = (size_t)(2048 / read_size);
+ uint64_t total_slots = remote_fd->cache->last_index_file_offset / read_size;
+
+ // perform the search
+ size_t read_count = 0;
+ int64_t current_file_offset = 0;
+ uint32_t i;
+ do {
+ // at this point, we need to read index events; read them from the file until it's necessary to grab them from the shared
+ // memory snapshot
+ // and crop file reading to the point where we last scanned
+ number_slots = (size_t)MIN(number_slots, total_slots);
+
+ // if out of file to read (as of the time we entered this function), try to use shared memory snapshot
+ if (number_slots == 0) {
+ if (remote_fd->cache->shmem &&
+ remote_fd->cache->snapshot.start_index_offset + remote_fd->cache->snapshot.next_free_index_buffer_offset >
+ (uint64_t)current_file_offset) {
+ // use shared memory
+ target_32_index = (stack_logging_index_event32 *)remote_fd->cache->snapshot.index_buffer;
+ target_64_index = (stack_logging_index_event64 *)remote_fd->cache->snapshot.index_buffer;
+ read_count = (uint32_t)(remote_fd->cache->snapshot.start_index_offset +
+ remote_fd->cache->snapshot.next_free_index_buffer_offset - current_file_offset) /
+ read_size;
+ current_file_offset += read_count * read_size;
+ } else {
+ break;
+ }
+ } else {
+ // get and save index (enumerator could modify)
+ fseeko(the_index, current_file_offset, SEEK_SET);
+ read_count = fread(bufferSpace, read_size, number_slots, the_index);
+ current_file_offset = ftello(the_index);
+ total_slots -= read_count;
+ }
+
+ if (remote_fd->task_is_64_bit) {
+ for (i = 0; i < read_count; i++) {
+ if (reading_all_addresses || target_64_index[i].address == target_addr_64) {
+ pass_record.address = STACK_LOGGING_DISGUISE(target_64_index[i].address);
+ pass_record.argument = target_64_index[i].argument;
+ pass_record.stack_identifier = STACK_LOGGING_OFFSET(target_64_index[i].offset_and_flags);
+ pass_record.type_flags = STACK_LOGGING_FLAGS_AND_USER_TAG(target_64_index[i].offset_and_flags);
+ enumerator(pass_record, context);
+ }
+ }
+ } else {
+ for (i = 0; i < read_count; i++) {
+ if (reading_all_addresses || target_32_index[i].address == target_addr_32) {
+ pass_record.address = STACK_LOGGING_DISGUISE(target_32_index[i].address);
+ pass_record.argument = target_32_index[i].argument;
+ pass_record.stack_identifier = STACK_LOGGING_OFFSET(target_32_index[i].offset_and_flags);
+ pass_record.type_flags = STACK_LOGGING_FLAGS_AND_USER_TAG(target_32_index[i].offset_and_flags);
+ enumerator(pass_record, context);
+ }
+ }
+ }
+ } while (read_count);
+
+ release_file_streams_for_task(task);
+ return err;
+}
+
+uint64_t
+__mach_stack_logging_stackid_for_vm_region(task_t task, mach_vm_address_t address)
+{
+ remote_task_file_streams *remote_fd = retain_file_streams_for_task(task, 0);
+ if (remote_fd == NULL) {
+ return __invalid_stack_id;
+ }
+
+ kern_return_t err = update_cache_for_file_streams(remote_fd);
+ if (err != KERN_SUCCESS) {
+ release_file_streams_for_task(task);
+ return __invalid_stack_id;
+ }
+
+ uint64_t stackid = __invalid_stack_id;
+
+ if (remote_fd->cache && remote_fd->cache->vm_stackid_table) {
+ stackid = radix_tree_lookup(remote_fd->cache->vm_stackid_table, address);
+ }
+
+ release_file_streams_for_task(task);
+ return stackid;
+}
+
+kern_return_t
+__mach_stack_logging_frames_for_uniqued_stack(task_t task,
+ uint64_t stack_identifier,
+ mach_vm_address_t *stack_frames_buffer,
+ uint32_t max_stack_frames,
+ uint32_t *count)
+{
+ return __mach_stack_logging_get_frames_for_stackid(task, stack_identifier, stack_frames_buffer, max_stack_frames, count, NULL);
+}
+
+
+kern_return_t
+__mach_stack_logging_get_frames_for_stackid(task_t task,
+ uint64_t stack_identifier,
+ mach_vm_address_t *stack_frames_buffer,
+ uint32_t max_stack_frames,
+ uint32_t *count,
+ bool *last_frame_is_threadid)
+{
+ remote_task_file_streams *remote_fd = retain_file_streams_for_task(task, 0);
+ if (remote_fd == NULL) {
+ return KERN_FAILURE;
+ }
+
+ // ensure that the uniquing table snapshot is valid
+ kern_return_t err = update_cache_for_file_streams(remote_fd);
+ if (err != KERN_SUCCESS) {
+ release_file_streams_for_task(task);
+ return err;
+ }
+
+ bool lite_mode = remote_fd->cache->lite_mode;
+
+ unwind_stack_from_table_index(&remote_fd->cache->uniquing_table_snapshot, stack_identifier, stack_frames_buffer, count, max_stack_frames, lite_mode);
+
+ release_file_streams_for_task(task);
+
+ if (last_frame_is_threadid) {
+ *last_frame_is_threadid = !lite_mode;
+ }
+
+ if (*count) {
+ return KERN_SUCCESS;
+ } else {
+ return KERN_FAILURE;
+ }
+}
+
+kern_return_t
+__attribute__((visibility("default")))
+__mach_stack_logging_uniquing_table_read_stack(struct backtrace_uniquing_table *uniquing_table,
+ uint64_t stackid,
+ mach_vm_address_t *out_frames_buffer,
+ uint32_t *out_frames_count,
+ uint32_t max_frames)
+{
+ unwind_stack_from_table_index(uniquing_table, stackid, out_frames_buffer, out_frames_count, max_frames, uniquing_table->
+ nodes_use_refcount);
+ return *out_frames_count ? KERN_SUCCESS : KERN_FAILURE;
+}
+
+
+struct backtrace_uniquing_table *
+__mach_stack_logging_copy_uniquing_table(task_t task)
+{
+ remote_task_file_streams *remote_fd = retain_file_streams_for_task(task, 0);
+ if (remote_fd == NULL) {
+ return NULL;
+ }
+
+ // ensure that the uniquing table snapshot is valid
+ kern_return_t err = update_cache_for_file_streams(remote_fd);
+ if (err != KERN_SUCCESS || remote_fds->cache->uniquing_table_snapshot.numPages == 0) {
+ release_file_streams_for_task(task);
+ return NULL;
+ }
+
+ /* Steal the uniqing table snapshot. A new snapshot will be taken next time someone calls
+ * update_cache_for_file_streams
+ */
+ backtrace_uniquing_table *table = malloc(sizeof(backtrace_uniquing_table));
+ memcpy(table, &remote_fds->cache->uniquing_table_snapshot, sizeof(backtrace_uniquing_table));
+ bzero(&remote_fds->cache->uniquing_table_snapshot, sizeof(backtrace_uniquing_table));
+ remote_fds->cache->uniquing_table_snapshot.in_client_process = true;
+
+ table->refcount = 1;
+
+ release_file_streams_for_task(task);
+
+ return table;
+}
+
+
+void
+__mach_stack_logging_uniquing_table_release(struct backtrace_uniquing_table *table)
+{
+ if (!table) {
+ return;
+ }
+ assert(table->refcount > 0);
+ table->refcount--;
+ if (table->refcount == 0) {
+ free_uniquing_table_chunks(table);
+ free(table);
+ }
+}
+
+void
+__mach_stack_logging_uniquing_table_retain(struct backtrace_uniquing_table *table)
+{
+ assert(table->refcount > 0);
+ table->refcount++;
+}
+
+static const size_t uniquingTableDataAlign = 16 * 1024;
+static const size_t uniquingTableHeaderLength = 16;
+
+static inline size_t roundUp(size_t x, size_t alignment)
+{
+ return x + (-x % alignment);
+}
+
+size_t
+__mach_stack_logging_uniquing_table_sizeof(struct backtrace_uniquing_table *table)
+{
+ size_t size = 0;
+ size += uniquingTableHeaderLength; //header
+ size += sizeof(backtrace_uniquing_table);
+ size = roundUp(size, uniquingTableDataAlign);
+ assert(table->in_client_process);
+ table_chunk_header_t *table_chunk_header = table->u.first_table_chunk_hdr;
+ while (table_chunk_header) {
+ size += 2 * sizeof(mach_vm_address_t) * table_chunk_header->num_nodes_in_chunk;
+ table_chunk_header = table_chunk_header->next_table_chunk_header;
+ }
+ return size;
+}
+
+
+void *
+__mach_stack_logging_uniquing_table_serialize(struct backtrace_uniquing_table *table, mach_vm_size_t *size)
+{
+ *size = __mach_stack_logging_uniquing_table_sizeof(table);
+
+ mach_vm_address_t buffer_address = 0;
+ kern_return_t kr = mach_vm_allocate(mach_task_self(), &buffer_address, *size, VM_FLAGS_ANYWHERE);
+ if (kr != KERN_SUCCESS) {
+ *size = 0;
+ return NULL;
+ }
+
+ void *buffer = (void*)buffer_address;
+
+ uint8_t *p = buffer;
+
+ memcpy(p, "MslUniquingTable", uniquingTableHeaderLength);
+ p += uniquingTableHeaderLength;
+
+ memcpy(p, table, sizeof(backtrace_uniquing_table));
+ p += sizeof(backtrace_uniquing_table);
+
+ p = ((uint8_t*)buffer) + roundUp(p - (uint8_t*)buffer, uniquingTableDataAlign);
+
+ table_chunk_header_t *table_chunk_header = table->u.first_table_chunk_hdr;
+ uint64_t num_nodes = 0;
+ while (table_chunk_header) {
+ num_nodes += table_chunk_header->num_nodes_in_chunk;
+ size_t chunk_size = 2 * sizeof(mach_vm_address_t) * (size_t)table_chunk_header->num_nodes_in_chunk;
+ kr = mach_vm_copy(mach_task_self(), (mach_vm_address_t)table_chunk_header->table_chunk, chunk_size, (vm_address_t)p);
+ if (kr != KERN_SUCCESS) {
+ memcpy(p, table_chunk_header->table_chunk, chunk_size);
+ }
+ p += chunk_size;
+ table_chunk_header = table_chunk_header->next_table_chunk_header;
+ }
+
+ assert(num_nodes == table->numNodes);
+
+ return buffer;
+}
+
+struct backtrace_uniquing_table *
+__mach_stack_logging_uniquing_table_copy_from_serialized(void *buffer, size_t size)
+{
+ if (size < uniquingTableHeaderLength + sizeof(backtrace_uniquing_table)) {
+ return NULL;
+ }
+ uint8_t *p = buffer;
+
+ if (strncmp(buffer, "MslUniquingTable", uniquingTableHeaderLength) != 0) {
+ return NULL;
+ }
+ p += uniquingTableHeaderLength;
+
+ backtrace_uniquing_table *table = malloc(sizeof(backtrace_uniquing_table));
+ memcpy(table, p, sizeof(backtrace_uniquing_table));
+ p += sizeof(backtrace_uniquing_table);
+
+ p = ((uint8_t*)buffer) + roundUp(p - (uint8_t*)buffer, uniquingTableDataAlign);
+
+ table->u.first_table_chunk_hdr = malloc(sizeof(table_chunk_header_t));
+ table->refcount = 1;
+
+ mach_vm_size_t chunkSize = 2 * table->numNodes * sizeof(mach_vm_address_t);
+
+ mach_vm_address_t chunkAddr = 0;
+
+ if (roundUp(uniquingTableHeaderLength + sizeof(backtrace_uniquing_table), uniquingTableDataAlign) + chunkSize < size ) {
+ goto fail;
+ }
+
+ kern_return_t kr = mach_vm_allocate(mach_task_self(), &chunkAddr, chunkSize, VM_FLAGS_ANYWHERE | VM_MAKE_TAG(VM_MEMORY_ANALYSIS_TOOL));
+ if (kr != KERN_SUCCESS) {
+ goto fail;
+ }
+
+ table->u.first_table_chunk_hdr->num_nodes_in_chunk = table->numNodes;
+ table->u.first_table_chunk_hdr->table_chunk_size = chunkSize;
+ table->u.first_table_chunk_hdr->table_chunk = (mach_vm_address_t*) chunkAddr;
+ table->u.first_table_chunk_hdr->next_table_chunk_header = NULL;
+
+ kr = mach_vm_copy(mach_task_self(), (mach_vm_address_t)p, chunkSize, (mach_vm_address_t) table->u.first_table_chunk_hdr->table_chunk);
+ if (kr != KERN_SUCCESS) {
+ goto fail;
+ }
+
+ return table;
+
+fail:
+ if (table) {
+ if (table->u.first_table_chunk_hdr) {
+ free(table->u.first_table_chunk_hdr);
+ }
+ free(table);
+ }
+ if (chunkAddr) {
+ mach_vm_deallocate(mach_task_self(), chunkAddr, chunkSize);
+ }
+ return NULL;
+}
+
+
+#ifdef TEST_DISK_STACK_LOGGING
+
+// cc -o stack_logging_disk stack_logging_disk.c -DTEST_DISK_STACK_LOGGING
+
+#include <sys/wait.h>
+
+int
+main()
+{
+ int status;
+ int i;
+ size_t total_globals = 0ul;
+
+ fprintf(stderr, "master test process is %d\n", getpid());
+ fprintf(stderr, "sizeof pre_write_buffers: %lu\n", sizeof(pre_write_buffers));
+ total_globals += sizeof(pre_write_buffers);
+ fprintf(stderr, "sizeof stack_buffer: %lu\n", sizeof(stack_buffer));
+ total_globals += sizeof(stack_buffer);
+ fprintf(stderr, "sizeof last_logged_malloc_address: %lu\n", sizeof(last_logged_malloc_address));
+ total_globals += sizeof(last_logged_malloc_address);
+ fprintf(stderr, "sizeof stack_log_file_base_name: %lu\n", sizeof(stack_log_file_base_name));
+ total_globals += sizeof(stack_log_file_base_name);
+ fprintf(stderr, "sizeof stack_log_file_suffix: %lu\n", sizeof(stack_log_file_suffix));
+ total_globals += sizeof(stack_log_file_suffix);
+ fprintf(stderr, "sizeof __stack_log_file_path__ (index_file_path): %lu\n", (size_t)PATH_MAX);
+ total_globals += (size_t)PATH_MAX;
+ fprintf(stderr, "sizeof index_file_descriptor: %lu\n", sizeof(index_file_descriptor));
+ total_globals += sizeof(index_file_descriptor);
+ fprintf(stderr, "sizeof remote_fds: %lu\n", sizeof(remote_fds));
+ total_globals += sizeof(remote_fds);
+ fprintf(stderr, "sizeof next_remote_task_fd: %lu\n", sizeof(next_remote_task_fd));
+ total_globals += sizeof(next_remote_task_fd);
+ fprintf(stderr, "sizeof remote_task_fd_count: %lu\n", sizeof(remote_task_fd_count));
+ total_globals += sizeof(remote_task_fd_count);
+ fprintf(stderr, "sizeof remote_fd_list_lock: %lu\n", sizeof(remote_fd_list_lock));
+ total_globals += sizeof(remote_fd_list_lock);
+ fprintf(stderr, "sizeof logging_use_compaction: %lu\n", sizeof(logging_use_compaction));
+ total_globals += sizeof(logging_use_compaction);
+
+ fprintf(stderr, "size of all global data: %lu\n", total_globals);
+
+ create_log_file();
+
+ // create a few child processes and exit them cleanly so their logs should get cleaned up
+ fprintf(stderr, "\ncreating child processes and exiting cleanly\n");
+ for (i = 0; i < 3; i++) {
+ if (fork() == 0) {
+ fprintf(stderr, "\nin child processes %d\n", getpid());
+ create_log_file();
+ fprintf(stderr, "exiting child processes %d\n", getpid());
+ exit(1);
+ }
+ wait(&status);
+ }
+
+ // create a few child processes and abruptly _exit them, leaving their logs around
+ fprintf(stderr, "\ncreating child processes and exiting abruptly, leaving logs around\n");
+ for (i = 0; i < 3; i++) {
+ if (fork() == 0) {
+ fprintf(stderr, "\nin child processes %d\n", getpid());
+ create_log_file();
+ fprintf(stderr, "exiting child processes %d\n", getpid());
+ _exit(1);
+ }
+ wait(&status);
+ }
+
+ // this should reap any remaining logs
+ fprintf(stderr, "\nexiting master test process %d\n", getpid());
+ delete_log_files();
+ return 0;
+}
+
+#endif
+
+/* vim: set noet:ts=4:sw=4:cindent: */