summaryrefslogtreecommitdiffstats
path: root/xpcom/glue/FileUtils.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'xpcom/glue/FileUtils.cpp')
-rw-r--r--xpcom/glue/FileUtils.cpp568
1 files changed, 568 insertions, 0 deletions
diff --git a/xpcom/glue/FileUtils.cpp b/xpcom/glue/FileUtils.cpp
new file mode 100644
index 000000000..699812461
--- /dev/null
+++ b/xpcom/glue/FileUtils.cpp
@@ -0,0 +1,568 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <errno.h>
+#include <stdio.h>
+
+#include "nscore.h"
+#include "nsStringGlue.h"
+#include "private/pprio.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/FileUtils.h"
+
+#if defined(XP_MACOSX)
+#include <fcntl.h>
+#include <unistd.h>
+#include <mach/machine.h>
+#include <mach-o/fat.h>
+#include <mach-o/loader.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <limits.h>
+#elif defined(XP_UNIX)
+#include <fcntl.h>
+#include <unistd.h>
+#if defined(LINUX)
+#include <elf.h>
+#endif
+#include <sys/types.h>
+#include <sys/stat.h>
+#elif defined(XP_WIN)
+#include <windows.h>
+#endif
+
+// Functions that are not to be used in standalone glue must be implemented
+// within this #if block
+#if !defined(XPCOM_GLUE)
+
+bool
+mozilla::fallocate(PRFileDesc* aFD, int64_t aLength)
+{
+#if defined(HAVE_POSIX_FALLOCATE)
+ return posix_fallocate(PR_FileDesc2NativeHandle(aFD), 0, aLength) == 0;
+#elif defined(XP_WIN)
+ int64_t oldpos = PR_Seek64(aFD, 0, PR_SEEK_CUR);
+ if (oldpos == -1) {
+ return false;
+ }
+
+ if (PR_Seek64(aFD, aLength, PR_SEEK_SET) != aLength) {
+ return false;
+ }
+
+ bool retval = (0 != SetEndOfFile((HANDLE)PR_FileDesc2NativeHandle(aFD)));
+
+ PR_Seek64(aFD, oldpos, PR_SEEK_SET);
+ return retval;
+#elif defined(XP_MACOSX)
+ int fd = PR_FileDesc2NativeHandle(aFD);
+ fstore_t store = {F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, aLength};
+ // Try to get a continous chunk of disk space
+ int ret = fcntl(fd, F_PREALLOCATE, &store);
+ if (ret == -1) {
+ // OK, perhaps we are too fragmented, allocate non-continuous
+ store.fst_flags = F_ALLOCATEALL;
+ ret = fcntl(fd, F_PREALLOCATE, &store);
+ if (ret == -1) {
+ return false;
+ }
+ }
+ return ftruncate(fd, aLength) == 0;
+#elif defined(XP_UNIX)
+ // The following is copied from fcntlSizeHint in sqlite
+ /* If the OS does not have posix_fallocate(), fake it. First use
+ ** ftruncate() to set the file size, then write a single byte to
+ ** the last byte in each block within the extended region. This
+ ** is the same technique used by glibc to implement posix_fallocate()
+ ** on systems that do not have a real fallocate() system call.
+ */
+ int64_t oldpos = PR_Seek64(aFD, 0, PR_SEEK_CUR);
+ if (oldpos == -1) {
+ return false;
+ }
+
+ struct stat buf;
+ int fd = PR_FileDesc2NativeHandle(aFD);
+ if (fstat(fd, &buf)) {
+ return false;
+ }
+
+ if (buf.st_size >= aLength) {
+ return false;
+ }
+
+ const int nBlk = buf.st_blksize;
+
+ if (!nBlk) {
+ return false;
+ }
+
+ if (ftruncate(fd, aLength)) {
+ return false;
+ }
+
+ int nWrite; // Return value from write()
+ int64_t iWrite = ((buf.st_size + 2 * nBlk - 1) / nBlk) * nBlk - 1; // Next offset to write to
+ while (iWrite < aLength) {
+ nWrite = 0;
+ if (PR_Seek64(aFD, iWrite, PR_SEEK_SET) == iWrite) {
+ nWrite = PR_Write(aFD, "", 1);
+ }
+ if (nWrite != 1) {
+ break;
+ }
+ iWrite += nBlk;
+ }
+
+ PR_Seek64(aFD, oldpos, PR_SEEK_SET);
+ return nWrite == 1;
+#endif
+ return false;
+}
+
+#ifdef ReadSysFile_PRESENT
+
+bool
+mozilla::ReadSysFile(
+ const char* aFilename,
+ char* aBuf,
+ size_t aBufSize)
+{
+ int fd = MOZ_TEMP_FAILURE_RETRY(open(aFilename, O_RDONLY));
+ if (fd < 0) {
+ return false;
+ }
+ ScopedClose autoClose(fd);
+ if (aBufSize == 0) {
+ return true;
+ }
+ ssize_t bytesRead;
+ size_t offset = 0;
+ do {
+ bytesRead = MOZ_TEMP_FAILURE_RETRY(read(fd, aBuf + offset,
+ aBufSize - offset));
+ if (bytesRead == -1) {
+ return false;
+ }
+ offset += bytesRead;
+ } while (bytesRead > 0 && offset < aBufSize);
+ MOZ_ASSERT(offset <= aBufSize);
+ if (offset > 0 && aBuf[offset - 1] == '\n') {
+ offset--;
+ }
+ if (offset == aBufSize) {
+ MOZ_ASSERT(offset > 0);
+ offset--;
+ }
+ aBuf[offset] = '\0';
+ return true;
+}
+
+bool
+mozilla::ReadSysFile(
+ const char* aFilename,
+ int* aVal)
+{
+ char valBuf[32];
+ if (!ReadSysFile(aFilename, valBuf, sizeof(valBuf))) {
+ return false;
+ }
+ return sscanf(valBuf, "%d", aVal) == 1;
+}
+
+bool
+mozilla::ReadSysFile(
+ const char* aFilename,
+ bool* aVal)
+{
+ int v;
+ if (!ReadSysFile(aFilename, &v)) {
+ return false;
+ }
+ *aVal = (v != 0);
+ return true;
+}
+
+#endif /* ReadSysFile_PRESENT */
+
+#ifdef WriteSysFile_PRESENT
+
+bool
+mozilla::WriteSysFile(
+ const char* aFilename,
+ const char* aBuf)
+{
+ size_t aBufSize = strlen(aBuf);
+ int fd = MOZ_TEMP_FAILURE_RETRY(open(aFilename, O_WRONLY));
+ if (fd < 0) {
+ return false;
+ }
+ ScopedClose autoClose(fd);
+ ssize_t bytesWritten;
+ size_t offset = 0;
+ do {
+ bytesWritten = MOZ_TEMP_FAILURE_RETRY(write(fd, aBuf + offset,
+ aBufSize - offset));
+ if (bytesWritten == -1) {
+ return false;
+ }
+ offset += bytesWritten;
+ } while (bytesWritten > 0 && offset < aBufSize);
+ MOZ_ASSERT(offset == aBufSize);
+ return true;
+}
+
+#endif /* WriteSysFile_PRESENT */
+
+void
+mozilla::ReadAheadLib(nsIFile* aFile)
+{
+#if defined(XP_WIN)
+ nsAutoString path;
+ if (!aFile || NS_FAILED(aFile->GetPath(path))) {
+ return;
+ }
+ ReadAheadLib(path.get());
+#elif defined(LINUX) && !defined(ANDROID) || defined(XP_MACOSX)
+ nsAutoCString nativePath;
+ if (!aFile || NS_FAILED(aFile->GetNativePath(nativePath))) {
+ return;
+ }
+ ReadAheadLib(nativePath.get());
+#endif
+}
+
+void
+mozilla::ReadAheadFile(nsIFile* aFile, const size_t aOffset,
+ const size_t aCount, mozilla::filedesc_t* aOutFd)
+{
+#if defined(XP_WIN)
+ nsAutoString path;
+ if (!aFile || NS_FAILED(aFile->GetPath(path))) {
+ return;
+ }
+ ReadAheadFile(path.get(), aOffset, aCount, aOutFd);
+#elif defined(LINUX) && !defined(ANDROID) || defined(XP_MACOSX)
+ nsAutoCString nativePath;
+ if (!aFile || NS_FAILED(aFile->GetNativePath(nativePath))) {
+ return;
+ }
+ ReadAheadFile(nativePath.get(), aOffset, aCount, aOutFd);
+#endif
+}
+
+#endif // !defined(XPCOM_GLUE)
+
+#if defined(LINUX) && !defined(ANDROID)
+
+static const unsigned int bufsize = 4096;
+
+#ifdef __LP64__
+typedef Elf64_Ehdr Elf_Ehdr;
+typedef Elf64_Phdr Elf_Phdr;
+static const unsigned char ELFCLASS = ELFCLASS64;
+typedef Elf64_Off Elf_Off;
+#else
+typedef Elf32_Ehdr Elf_Ehdr;
+typedef Elf32_Phdr Elf_Phdr;
+static const unsigned char ELFCLASS = ELFCLASS32;
+typedef Elf32_Off Elf_Off;
+#endif
+
+#elif defined(XP_MACOSX)
+
+#if defined(__i386__)
+static const uint32_t CPU_TYPE = CPU_TYPE_X86;
+#elif defined(__x86_64__)
+static const uint32_t CPU_TYPE = CPU_TYPE_X86_64;
+#elif defined(__ppc__)
+static const uint32_t CPU_TYPE = CPU_TYPE_POWERPC;
+#elif defined(__ppc64__)
+static const uint32_t CPU_TYPE = CPU_TYPE_POWERPC64;
+#else
+#error Unsupported CPU type
+#endif
+
+#ifdef __LP64__
+#undef LC_SEGMENT
+#define LC_SEGMENT LC_SEGMENT_64
+#undef MH_MAGIC
+#define MH_MAGIC MH_MAGIC_64
+#define cpu_mach_header mach_header_64
+#define segment_command segment_command_64
+#else
+#define cpu_mach_header mach_header
+#endif
+
+class ScopedMMap
+{
+public:
+ explicit ScopedMMap(const char* aFilePath)
+ : buf(nullptr)
+ {
+ fd = open(aFilePath, O_RDONLY);
+ if (fd < 0) {
+ return;
+ }
+ struct stat st;
+ if (fstat(fd, &st) < 0) {
+ return;
+ }
+ size = st.st_size;
+ buf = (char*)mmap(nullptr, size, PROT_READ, MAP_PRIVATE, fd, 0);
+ }
+ ~ScopedMMap()
+ {
+ if (buf) {
+ munmap(buf, size);
+ }
+ if (fd >= 0) {
+ close(fd);
+ }
+ }
+ operator char*() { return buf; }
+ int getFd() { return fd; }
+private:
+ int fd;
+ char* buf;
+ size_t size;
+};
+#endif
+
+void
+mozilla::ReadAhead(mozilla::filedesc_t aFd, const size_t aOffset,
+ const size_t aCount)
+{
+#if defined(XP_WIN)
+
+ LARGE_INTEGER fpOriginal;
+ LARGE_INTEGER fpOffset;
+#if defined(HAVE_LONG_LONG)
+ fpOffset.QuadPart = 0;
+#else
+ fpOffset.u.LowPart = 0;
+ fpOffset.u.HighPart = 0;
+#endif
+
+ // Get the current file pointer so that we can restore it. This isn't
+ // really necessary other than to provide the same semantics regarding the
+ // file pointer that other platforms do
+ if (!SetFilePointerEx(aFd, fpOffset, &fpOriginal, FILE_CURRENT)) {
+ return;
+ }
+
+ if (aOffset) {
+#if defined(HAVE_LONG_LONG)
+ fpOffset.QuadPart = static_cast<LONGLONG>(aOffset);
+#else
+ fpOffset.u.LowPart = aOffset;
+ fpOffset.u.HighPart = 0;
+#endif
+
+ if (!SetFilePointerEx(aFd, fpOffset, nullptr, FILE_BEGIN)) {
+ return;
+ }
+ }
+
+ char buf[64 * 1024];
+ size_t totalBytesRead = 0;
+ DWORD dwBytesRead;
+ // Do dummy reads to trigger kernel-side readhead via FILE_FLAG_SEQUENTIAL_SCAN.
+ // Abort when underfilling because during testing the buffers are read fully
+ // A buffer that's not keeping up would imply that readahead isn't working right
+ while (totalBytesRead < aCount &&
+ ReadFile(aFd, buf, sizeof(buf), &dwBytesRead, nullptr) &&
+ dwBytesRead == sizeof(buf)) {
+ totalBytesRead += dwBytesRead;
+ }
+
+ // Restore the file pointer
+ SetFilePointerEx(aFd, fpOriginal, nullptr, FILE_BEGIN);
+
+#elif defined(LINUX) && !defined(ANDROID)
+
+ readahead(aFd, aOffset, aCount);
+
+#elif defined(XP_MACOSX)
+
+ struct radvisory ra;
+ ra.ra_offset = aOffset;
+ ra.ra_count = aCount;
+ // The F_RDADVISE fcntl is equivalent to Linux' readahead() system call.
+ fcntl(aFd, F_RDADVISE, &ra);
+
+#endif
+}
+
+void
+mozilla::ReadAheadLib(mozilla::pathstr_t aFilePath)
+{
+ if (!aFilePath) {
+ return;
+ }
+#if defined(XP_WIN)
+ ReadAheadFile(aFilePath);
+#elif defined(LINUX) && !defined(ANDROID)
+ int fd = open(aFilePath, O_RDONLY);
+ if (fd < 0) {
+ return;
+ }
+
+ union
+ {
+ char buf[bufsize];
+ Elf_Ehdr ehdr;
+ } elf;
+ // Read ELF header (ehdr) and program header table (phdr).
+ // We check that the ELF magic is found, that the ELF class matches
+ // our own, and that the program header table as defined in the ELF
+ // headers fits in the buffer we read.
+ if ((read(fd, elf.buf, bufsize) <= 0) ||
+ (memcmp(elf.buf, ELFMAG, 4)) ||
+ (elf.ehdr.e_ident[EI_CLASS] != ELFCLASS) ||
+ // Upcast e_phentsize so the multiplication is done in the same precision
+ // as the subsequent addition, to satisfy static analyzers and avoid
+ // issues with abnormally large program header tables.
+ (elf.ehdr.e_phoff + (static_cast<Elf_Off>(elf.ehdr.e_phentsize) *
+ elf.ehdr.e_phnum) >= bufsize)) {
+ close(fd);
+ return;
+ }
+ // The program header table contains segment definitions. One such
+ // segment type is PT_LOAD, which describes how the dynamic loader
+ // is going to map the file in memory. We use that information to
+ // find the biggest offset from the library that will be mapped in
+ // memory.
+ Elf_Phdr* phdr = (Elf_Phdr*)&elf.buf[elf.ehdr.e_phoff];
+ Elf_Off end = 0;
+ for (int phnum = elf.ehdr.e_phnum; phnum; phdr++, phnum--) {
+ if ((phdr->p_type == PT_LOAD) &&
+ (end < phdr->p_offset + phdr->p_filesz)) {
+ end = phdr->p_offset + phdr->p_filesz;
+ }
+ }
+ // Let the kernel read ahead what the dynamic loader is going to
+ // map in memory soon after.
+ if (end > 0) {
+ ReadAhead(fd, 0, end);
+ }
+ close(fd);
+#elif defined(XP_MACOSX)
+ ScopedMMap buf(aFilePath);
+ char* base = buf;
+ if (!base) {
+ return;
+ }
+
+ // An OSX binary might either be a fat (universal) binary or a
+ // Mach-O binary. A fat binary actually embeds several Mach-O
+ // binaries. If we have a fat binary, find the offset where the
+ // Mach-O binary for our CPU type can be found.
+ struct fat_header* fh = (struct fat_header*)base;
+
+ if (OSSwapBigToHostInt32(fh->magic) == FAT_MAGIC) {
+ uint32_t nfat_arch = OSSwapBigToHostInt32(fh->nfat_arch);
+ struct fat_arch* arch = (struct fat_arch*)&buf[sizeof(struct fat_header)];
+ for (; nfat_arch; arch++, nfat_arch--) {
+ if (OSSwapBigToHostInt32(arch->cputype) == CPU_TYPE) {
+ base += OSSwapBigToHostInt32(arch->offset);
+ break;
+ }
+ }
+ if (base == buf) {
+ return;
+ }
+ }
+
+ // Check Mach-O magic in the Mach header
+ struct cpu_mach_header* mh = (struct cpu_mach_header*)base;
+ if (mh->magic != MH_MAGIC) {
+ return;
+ }
+
+ // The Mach header is followed by a sequence of load commands.
+ // Each command has a header containing the command type and the
+ // command size. LD_SEGMENT commands describes how the dynamic
+ // loader is going to map the file in memory. We use that
+ // information to find the biggest offset from the library that
+ // will be mapped in memory.
+ char* cmd = &base[sizeof(struct cpu_mach_header)];
+ uint32_t end = 0;
+ for (uint32_t ncmds = mh->ncmds; ncmds; ncmds--) {
+ struct segment_command* sh = (struct segment_command*)cmd;
+ if (sh->cmd != LC_SEGMENT) {
+ continue;
+ }
+ if (end < sh->fileoff + sh->filesize) {
+ end = sh->fileoff + sh->filesize;
+ }
+ cmd += sh->cmdsize;
+ }
+ // Let the kernel read ahead what the dynamic loader is going to
+ // map in memory soon after.
+ if (end > 0) {
+ ReadAhead(buf.getFd(), base - buf, end);
+ }
+#endif
+}
+
+void
+mozilla::ReadAheadFile(mozilla::pathstr_t aFilePath, const size_t aOffset,
+ const size_t aCount, mozilla::filedesc_t* aOutFd)
+{
+#if defined(XP_WIN)
+ if (!aFilePath) {
+ if (aOutFd) {
+ *aOutFd = INVALID_HANDLE_VALUE;
+ }
+ return;
+ }
+ HANDLE fd = CreateFileW(aFilePath, GENERIC_READ, FILE_SHARE_READ, nullptr,
+ OPEN_EXISTING, FILE_FLAG_SEQUENTIAL_SCAN, nullptr);
+ if (aOutFd) {
+ *aOutFd = fd;
+ }
+ if (fd == INVALID_HANDLE_VALUE) {
+ return;
+ }
+ ReadAhead(fd, aOffset, aCount);
+ if (!aOutFd) {
+ CloseHandle(fd);
+ }
+#elif defined(LINUX) && !defined(ANDROID) || defined(XP_MACOSX)
+ if (!aFilePath) {
+ if (aOutFd) {
+ *aOutFd = -1;
+ }
+ return;
+ }
+ int fd = open(aFilePath, O_RDONLY);
+ if (aOutFd) {
+ *aOutFd = fd;
+ }
+ if (fd < 0) {
+ return;
+ }
+ size_t count;
+ if (aCount == SIZE_MAX) {
+ struct stat st;
+ if (fstat(fd, &st) < 0) {
+ if (!aOutFd) {
+ close(fd);
+ }
+ return;
+ }
+ count = st.st_size;
+ } else {
+ count = aCount;
+ }
+ ReadAhead(fd, aOffset, count);
+ if (!aOutFd) {
+ close(fd);
+ }
+#endif
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-18 15:57:31 +0000