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+++ dyld/dyld-955/common/ClosureFileSystemPhysical.cpp
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+/*
+ * Copyright (c) 2017 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 "ClosureFileSystemPhysical.h"
+
+#include <TargetConditionals.h>
+
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/errno.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <mach/mach.h>
+#if !TARGET_OS_SIMULATOR && !TARGET_OS_DRIVERKIT
+ #include <sandbox.h>
+ #include <sandbox/private.h>
+#endif
+#include <TargetConditionals.h>
+#include "MachOFile.h"
+#include "MachOAnalyzer.h"
+
+using dyld3::closure::FileSystemPhysical;
+
+bool FileSystemPhysical::getRealPath(const char possiblePath[MAXPATHLEN], char realPath[MAXPATHLEN]) const {
+ __block bool success = false;
+ // first pass: open file and ask kernel for canonical path
+ forEachPath(possiblePath, ^(const char* aPath, unsigned prefixLen, bool& stop) {
+ int fd = dyld3::open(aPath, O_RDONLY, 0);
+ if ( fd != -1 ) {
+ char tempPath[MAXPATHLEN];
+ success = (fcntl(fd, F_GETPATH, tempPath) == 0);
+ ::close(fd);
+ if ( success ) {
+ // if prefix was used, remove it
+ strcpy(realPath, &tempPath[prefixLen]);
+ }
+ stop = true;
+ }
+ });
+ if (success)
+ return success;
+
+ // second pass: file does not exist but may be a symlink to a non-existent file
+ // This is only for use on-device on platforms where dylibs are removed
+ if ( _overlayPath == nullptr && _rootPath == nullptr ) {
+ realpath(possiblePath, realPath);
+ int realpathErrno = errno;
+ // If realpath() resolves to a path which does not exist on disk, errno is set to ENOENT
+ success = (realpathErrno == ENOENT) || (realpathErrno == 0);
+ }
+ return success;
+}
+
+static bool sandboxBlocked(const char* path, const char* kind)
+{
+#if TARGET_OS_SIMULATOR || TARGET_OS_DRIVERKIT
+ // sandbox calls not yet supported in dyld_sim
+ return false;
+#else
+ sandbox_filter_type filter = (sandbox_filter_type)(SANDBOX_FILTER_PATH | SANDBOX_CHECK_NO_REPORT);
+ return ( sandbox_check(getpid(), kind, filter, path) > 0 );
+#endif
+}
+
+static bool sandboxBlockedMmap(const char* path)
+{
+ return sandboxBlocked(path, "file-map-executable");
+}
+
+static bool sandboxBlockedOpen(const char* path)
+{
+ return sandboxBlocked(path, "file-read-data");
+}
+
+static bool sandboxBlockedStat(const char* path)
+{
+ return sandboxBlocked(path, "file-read-metadata");
+}
+
+void FileSystemPhysical::forEachPath(const char* path, void (^handler)(const char* fullPath, unsigned prefixLen, bool& stop)) const
+{
+ bool stop = false;
+ char altPath[PATH_MAX];
+ if ( _overlayPath != nullptr ) {
+ strlcpy(altPath, _overlayPath, PATH_MAX);
+ strlcat(altPath, path, PATH_MAX);
+ handler(altPath, (unsigned)strlen(_overlayPath), stop);
+ if ( stop )
+ return;
+ }
+ if ( _rootPath != nullptr ) {
+ strlcpy(altPath, _rootPath, PATH_MAX);
+ if ( path[0] != '/' )
+ strlcat(altPath, "/", PATH_MAX);
+ strlcat(altPath, path, PATH_MAX);
+ handler(altPath, (unsigned)strlen(_rootPath), stop);
+ if ( stop )
+ return;
+ }
+ else {
+ handler(path, 0, stop);
+ }
+}
+
+static bool isFileRelativePath(const char* path)
+{
+ if ( path[0] == '/' )
+ return false;
+ if ( path[0] != '.' )
+ return true;
+ if ( path[1] == '/' )
+ return true;
+ if ( (path[1] == '.') && (path[2] == '/') )
+ return true;
+ return false;
+}
+
+// Returns true on success. If an error occurs the given callback will be called with the reason.
+// On success, info is filled with info about the loaded file. If the path supplied includes a symlink,
+// the supplier realerPath is filled in with the real path of the file, otherwise it is set to the empty string.
+bool FileSystemPhysical::loadFile(const char* path, LoadedFileInfo& info, char realerPath[MAXPATHLEN], void (^error)(const char* format, ...)) const {
+ if ( !_allowRelativePaths && isFileRelativePath(path) ) {
+ error("relative file paths not allowed '%s'", path);
+ return false;
+ }
+ // open file
+ __block int fd;
+ __block struct stat statBuf;
+ forEachPath(path, ^(const char* aPath, unsigned prefixLen, bool& stop) {
+ fd = dyld3::open(aPath, O_RDONLY, 0);
+ if ( fd == -1 ) {
+ int openErrno = errno;
+ if ( (openErrno == EPERM) && sandboxBlockedOpen(path) )
+ error("file system sandbox blocked open(\"%s\", O_RDONLY)", path);
+ else if ( (openErrno != ENOENT) && (openErrno != ENOTDIR) )
+ error("open(\"%s\", O_RDONLY) failed with errno=%d", path, openErrno);
+ }
+ else {
+ // get file info
+ if ( ::fstat(fd, &statBuf) != 0 ) {
+ int statErr = errno;
+ if ( (statErr == EPERM) && sandboxBlockedStat(path) )
+ error("file system sandbox blocked stat(\"%s\")", path);
+ else
+ error("stat(\"%s\") failed with errno=%d", path, errno);
+ ::close(fd);
+ fd = -1;
+ }
+ else {
+ // Get the realpath of the file if it is a symlink
+ char tempPath[MAXPATHLEN];
+ if ( fcntl(fd, F_GETPATH, tempPath) == 0 ) {
+ const char* realPathWithin = &tempPath[prefixLen];
+ // Don't set the realpath if it is just the same as the regular path
+ if ( strcmp(path, realPathWithin) == 0 ) {
+ // zero out realerPath if path is fine as-is
+ // <rdar://45018392> don't trash input 'path' if realerPath is same buffer as path
+ if ( realerPath != path )
+ realerPath[0] = '\0';
+ }
+ else
+ strcpy(realerPath, realPathWithin);
+ stop = true;
+ }
+ else {
+ error("Could not get real path for \"%s\"\n", path);
+ ::close(fd);
+ fd = -1;
+ }
+ }
+ }
+ });
+ if ( fd == -1 )
+ return false;
+
+ // only regular files can be loaded
+ if ( !S_ISREG(statBuf.st_mode) ) {
+ error("not a file for %s", path);
+ ::close(fd);
+ return false;
+ }
+
+ // mach-o files must be at list one page in size
+ if ( statBuf.st_size < 4096 ) {
+ error("file too short %s", path);
+ ::close(fd);
+ return false;
+ }
+
+ info.fileContent = nullptr;
+ info.fileContentLen = statBuf.st_size;
+ info.sliceOffset = 0;
+ info.sliceLen = statBuf.st_size;
+ info.isOSBinary = false;
+ info.inode = statBuf.st_ino;
+ info.mtime = statBuf.st_mtime;
+ info.path = path;
+
+ // mmap() whole file
+ void* wholeFile = ::mmap(nullptr, (size_t)statBuf.st_size, PROT_READ, MAP_PRIVATE|MAP_RESILIENT_CODESIGN, fd, 0);
+ if ( wholeFile == MAP_FAILED ) {
+ int mmapErr = errno;
+ if ( mmapErr == EPERM ) {
+ if ( sandboxBlockedMmap(path) )
+ error("file system sandbox blocked mmap() of '%s'", path);
+ else
+ error("code signing blocked mmap() of '%s'", path);
+ }
+ else {
+ error("mmap() failed with errno=%d for %s", errno, path);
+ }
+ ::close(fd);
+ return false;
+ }
+ info.fileContent = wholeFile;
+
+ // if this is an arm64e mach-o or a fat file with an arm64e slice we need to record if it is an OS binary
+#if TARGET_OS_OSX && __arm64e__
+ const MachOAnalyzer* ma = (MachOAnalyzer*)wholeFile;
+ if ( ma->hasMachOMagic() ) {
+ if ( (ma->cputype == CPU_TYPE_ARM64) && ((ma->cpusubtype & ~CPU_SUBTYPE_MASK) == CPU_SUBTYPE_ARM64E) ) {
+ if ( ma->isOSBinary(fd, 0, info.fileContentLen) )
+ info.isOSBinary = true;
+ }
+ }
+ else if ( const FatFile* fat = FatFile::isFatFile(wholeFile) ) {
+ Diagnostics diag;
+ fat->forEachSlice(diag, info.fileContentLen, ^(uint32_t sliceCpuType, uint32_t sliceCpuSubType, const void* sliceStart, uint64_t sliceSize, bool& stop) {
+ if ( (sliceCpuType == CPU_TYPE_ARM64) && ((sliceCpuSubType & ~CPU_SUBTYPE_MASK) == CPU_SUBTYPE_ARM64E) ) {
+ uint64_t sliceOffset = (uint8_t*)sliceStart-(uint8_t*)wholeFile;
+ const MachOAnalyzer* sliceMA = (MachOAnalyzer*)((uint8_t*)wholeFile + sliceOffset);
+ if ( sliceMA->isOSBinary(fd, sliceOffset, sliceSize) )
+ info.isOSBinary = true;
+ }
+ });
+ }
+#endif
+ // Set unmap as the unload method.
+ info.unload = [](const LoadedFileInfo& info) {
+ ::munmap((void*)info.fileContent, (size_t)info.fileContentLen);
+ };
+
+ ::close(fd);
+ return true;
+}
+
+void FileSystemPhysical::unloadFile(const LoadedFileInfo& info) const {
+ if (info.unload)
+ info.unload(info);
+}
+
+void FileSystemPhysical::unloadPartialFile(LoadedFileInfo& info, uint64_t keepStartOffset, uint64_t keepLength) const {
+ // Unmap from 0..keepStartOffset and (keepStartOffset+keepLength)..info.fileContentLen
+ if (keepStartOffset)
+ ::munmap((void*)info.fileContent, (size_t)trunc_page(keepStartOffset));
+ if ((keepStartOffset + keepLength) != info.fileContentLen) {
+ uintptr_t start = round_page((uintptr_t)info.fileContent + keepStartOffset + keepLength);
+ uintptr_t end = (uintptr_t)info.fileContent + (uintptr_t)info.fileContentLen;
+ ::munmap((void*)start, end - start);
+ }
+ info.fileContent = (const void*)((char*)info.fileContent + keepStartOffset);
+ info.fileContentLen = keepLength;
+}
+
+bool FileSystemPhysical::fileExists(const char* path, uint64_t* inode, uint64_t* mtime,
+ bool* issetuid, bool* inodesMatchRuntime) const {
+ __block bool result = false;
+ forEachPath(path, ^(const char* aPath, unsigned prefixLen, bool& stop) {
+ struct stat statBuf;
+ if ( dyld3::stat(aPath, &statBuf) == 0 ) {
+ if (inode)
+ *inode = statBuf.st_ino;
+ if (mtime)
+ *mtime = statBuf.st_mtime;
+ if (issetuid)
+ *issetuid = (statBuf.st_mode & (S_ISUID|S_ISGID));
+ if (inodesMatchRuntime)
+ *inodesMatchRuntime = true;
+ stop = true;
+ result = true;
+ }
+ });
+ return result;
+}