1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/glue/FileUtils.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,522 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include <errno.h>
1.10 +#include <stdio.h>
1.11 +
1.12 +#include "nscore.h"
1.13 +#include "nsStringGlue.h"
1.14 +#include "private/pprio.h"
1.15 +#include "mozilla/Assertions.h"
1.16 +#include "mozilla/FileUtils.h"
1.17 +
1.18 +#if defined(XP_MACOSX)
1.19 +#include <fcntl.h>
1.20 +#include <unistd.h>
1.21 +#include <mach/machine.h>
1.22 +#include <mach-o/fat.h>
1.23 +#include <mach-o/loader.h>
1.24 +#include <sys/mman.h>
1.25 +#include <sys/stat.h>
1.26 +#include <limits.h>
1.27 +#elif defined(XP_UNIX)
1.28 +#include <fcntl.h>
1.29 +#include <unistd.h>
1.30 +#if defined(LINUX)
1.31 +#include <elf.h>
1.32 +#endif
1.33 +#include <sys/types.h>
1.34 +#include <sys/stat.h>
1.35 +#elif defined(XP_WIN)
1.36 +#include <windows.h>
1.37 +#endif
1.38 +
1.39 +// Functions that are not to be used in standalone glue must be implemented
1.40 +// within this #if block
1.41 +#if !defined(XPCOM_GLUE)
1.42 +
1.43 +bool
1.44 +mozilla::fallocate(PRFileDesc *aFD, int64_t aLength)
1.45 +{
1.46 +#if defined(HAVE_POSIX_FALLOCATE)
1.47 + return posix_fallocate(PR_FileDesc2NativeHandle(aFD), 0, aLength) == 0;
1.48 +#elif defined(XP_WIN)
1.49 + int64_t oldpos = PR_Seek64(aFD, 0, PR_SEEK_CUR);
1.50 + if (oldpos == -1)
1.51 + return false;
1.52 +
1.53 + if (PR_Seek64(aFD, aLength, PR_SEEK_SET) != aLength)
1.54 + return false;
1.55 +
1.56 + bool retval = (0 != SetEndOfFile((HANDLE)PR_FileDesc2NativeHandle(aFD)));
1.57 +
1.58 + PR_Seek64(aFD, oldpos, PR_SEEK_SET);
1.59 + return retval;
1.60 +#elif defined(XP_MACOSX)
1.61 + int fd = PR_FileDesc2NativeHandle(aFD);
1.62 + fstore_t store = {F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, aLength};
1.63 + // Try to get a continous chunk of disk space
1.64 + int ret = fcntl(fd, F_PREALLOCATE, &store);
1.65 + if (-1 == ret) {
1.66 + // OK, perhaps we are too fragmented, allocate non-continuous
1.67 + store.fst_flags = F_ALLOCATEALL;
1.68 + ret = fcntl(fd, F_PREALLOCATE, &store);
1.69 + if (-1 == ret)
1.70 + return false;
1.71 + }
1.72 + return 0 == ftruncate(fd, aLength);
1.73 +#elif defined(XP_UNIX)
1.74 + // The following is copied from fcntlSizeHint in sqlite
1.75 + /* If the OS does not have posix_fallocate(), fake it. First use
1.76 + ** ftruncate() to set the file size, then write a single byte to
1.77 + ** the last byte in each block within the extended region. This
1.78 + ** is the same technique used by glibc to implement posix_fallocate()
1.79 + ** on systems that do not have a real fallocate() system call.
1.80 + */
1.81 + int64_t oldpos = PR_Seek64(aFD, 0, PR_SEEK_CUR);
1.82 + if (oldpos == -1)
1.83 + return false;
1.84 +
1.85 + struct stat buf;
1.86 + int fd = PR_FileDesc2NativeHandle(aFD);
1.87 + if (fstat(fd, &buf))
1.88 + return false;
1.89 +
1.90 + if (buf.st_size >= aLength)
1.91 + return false;
1.92 +
1.93 + const int nBlk = buf.st_blksize;
1.94 +
1.95 + if (!nBlk)
1.96 + return false;
1.97 +
1.98 + if (ftruncate(fd, aLength))
1.99 + return false;
1.100 +
1.101 + int nWrite; // Return value from write()
1.102 + int64_t iWrite = ((buf.st_size + 2 * nBlk - 1) / nBlk) * nBlk - 1; // Next offset to write to
1.103 + while (iWrite < aLength) {
1.104 + nWrite = 0;
1.105 + if (PR_Seek64(aFD, iWrite, PR_SEEK_SET) == iWrite)
1.106 + nWrite = PR_Write(aFD, "", 1);
1.107 + if (nWrite != 1) break;
1.108 + iWrite += nBlk;
1.109 + }
1.110 +
1.111 + PR_Seek64(aFD, oldpos, PR_SEEK_SET);
1.112 + return nWrite == 1;
1.113 +#endif
1.114 + return false;
1.115 +}
1.116 +
1.117 +#ifdef ReadSysFile_PRESENT
1.118 +
1.119 +bool
1.120 +mozilla::ReadSysFile(
1.121 + const char* aFilename,
1.122 + char* aBuf,
1.123 + size_t aBufSize)
1.124 +{
1.125 + int fd = MOZ_TEMP_FAILURE_RETRY(open(aFilename, O_RDONLY));
1.126 + if (fd < 0) {
1.127 + return false;
1.128 + }
1.129 + ScopedClose autoClose(fd);
1.130 + if (aBufSize == 0) {
1.131 + return true;
1.132 + }
1.133 + ssize_t bytesRead;
1.134 + size_t offset = 0;
1.135 + do {
1.136 + bytesRead = MOZ_TEMP_FAILURE_RETRY(
1.137 + read(fd, aBuf + offset, aBufSize - offset));
1.138 + if (bytesRead == -1) {
1.139 + return false;
1.140 + }
1.141 + offset += bytesRead;
1.142 + } while (bytesRead > 0 && offset < aBufSize);
1.143 + MOZ_ASSERT(offset <= aBufSize);
1.144 + if (offset > 0 && aBuf[offset - 1] == '\n') {
1.145 + offset--;
1.146 + }
1.147 + if (offset == aBufSize) {
1.148 + MOZ_ASSERT(offset > 0);
1.149 + offset--;
1.150 + }
1.151 + aBuf[offset] = '\0';
1.152 + return true;
1.153 +}
1.154 +
1.155 +bool
1.156 +mozilla::ReadSysFile(
1.157 + const char* aFilename,
1.158 + int* aVal)
1.159 +{
1.160 + char valBuf[32];
1.161 + if (!ReadSysFile(aFilename, valBuf, sizeof(valBuf))) {
1.162 + return false;
1.163 + }
1.164 + return sscanf(valBuf, "%d", aVal) == 1;
1.165 +}
1.166 +
1.167 +bool
1.168 +mozilla::ReadSysFile(
1.169 + const char* aFilename,
1.170 + bool* aVal)
1.171 +{
1.172 + int v;
1.173 + if (!ReadSysFile(aFilename, &v)) {
1.174 + return false;
1.175 + }
1.176 + *aVal = (v != 0);
1.177 + return true;
1.178 +}
1.179 +
1.180 +#endif /* ReadSysFile_PRESENT */
1.181 +
1.182 +void
1.183 +mozilla::ReadAheadLib(nsIFile* aFile)
1.184 +{
1.185 +#if defined(XP_WIN)
1.186 + nsAutoString path;
1.187 + if (!aFile || NS_FAILED(aFile->GetPath(path))) {
1.188 + return;
1.189 + }
1.190 + ReadAheadLib(path.get());
1.191 +#elif defined(LINUX) && !defined(ANDROID) || defined(XP_MACOSX)
1.192 + nsAutoCString nativePath;
1.193 + if (!aFile || NS_FAILED(aFile->GetNativePath(nativePath))) {
1.194 + return;
1.195 + }
1.196 + ReadAheadLib(nativePath.get());
1.197 +#endif
1.198 +}
1.199 +
1.200 +void
1.201 +mozilla::ReadAheadFile(nsIFile* aFile, const size_t aOffset,
1.202 + const size_t aCount, mozilla::filedesc_t* aOutFd)
1.203 +{
1.204 +#if defined(XP_WIN)
1.205 + nsAutoString path;
1.206 + if (!aFile || NS_FAILED(aFile->GetPath(path))) {
1.207 + return;
1.208 + }
1.209 + ReadAheadFile(path.get(), aOffset, aCount, aOutFd);
1.210 +#elif defined(LINUX) && !defined(ANDROID) || defined(XP_MACOSX)
1.211 + nsAutoCString nativePath;
1.212 + if (!aFile || NS_FAILED(aFile->GetNativePath(nativePath))) {
1.213 + return;
1.214 + }
1.215 + ReadAheadFile(nativePath.get(), aOffset, aCount, aOutFd);
1.216 +#endif
1.217 +}
1.218 +
1.219 +#endif // !defined(XPCOM_GLUE)
1.220 +
1.221 +#if defined(LINUX) && !defined(ANDROID)
1.222 +
1.223 +static const unsigned int bufsize = 4096;
1.224 +
1.225 +#ifdef __LP64__
1.226 +typedef Elf64_Ehdr Elf_Ehdr;
1.227 +typedef Elf64_Phdr Elf_Phdr;
1.228 +static const unsigned char ELFCLASS = ELFCLASS64;
1.229 +typedef Elf64_Off Elf_Off;
1.230 +#else
1.231 +typedef Elf32_Ehdr Elf_Ehdr;
1.232 +typedef Elf32_Phdr Elf_Phdr;
1.233 +static const unsigned char ELFCLASS = ELFCLASS32;
1.234 +typedef Elf32_Off Elf_Off;
1.235 +#endif
1.236 +
1.237 +#elif defined(XP_MACOSX)
1.238 +
1.239 +#if defined(__i386__)
1.240 +static const uint32_t CPU_TYPE = CPU_TYPE_X86;
1.241 +#elif defined(__x86_64__)
1.242 +static const uint32_t CPU_TYPE = CPU_TYPE_X86_64;
1.243 +#elif defined(__ppc__)
1.244 +static const uint32_t CPU_TYPE = CPU_TYPE_POWERPC;
1.245 +#elif defined(__ppc64__)
1.246 +static const uint32_t CPU_TYPE = CPU_TYPE_POWERPC64;
1.247 +#else
1.248 +#error Unsupported CPU type
1.249 +#endif
1.250 +
1.251 +#ifdef __LP64__
1.252 +#undef LC_SEGMENT
1.253 +#define LC_SEGMENT LC_SEGMENT_64
1.254 +#undef MH_MAGIC
1.255 +#define MH_MAGIC MH_MAGIC_64
1.256 +#define cpu_mach_header mach_header_64
1.257 +#define segment_command segment_command_64
1.258 +#else
1.259 +#define cpu_mach_header mach_header
1.260 +#endif
1.261 +
1.262 +class ScopedMMap
1.263 +{
1.264 +public:
1.265 + ScopedMMap(const char *aFilePath)
1.266 + : buf(nullptr)
1.267 + {
1.268 + fd = open(aFilePath, O_RDONLY);
1.269 + if (fd < 0) {
1.270 + return;
1.271 + }
1.272 + struct stat st;
1.273 + if (fstat(fd, &st) < 0) {
1.274 + return;
1.275 + }
1.276 + size = st.st_size;
1.277 + buf = (char *)mmap(nullptr, size, PROT_READ, MAP_PRIVATE, fd, 0);
1.278 + }
1.279 + ~ScopedMMap()
1.280 + {
1.281 + if (buf) {
1.282 + munmap(buf, size);
1.283 + }
1.284 + if (fd >= 0) {
1.285 + close(fd);
1.286 + }
1.287 + }
1.288 + operator char *() { return buf; }
1.289 + int getFd() { return fd; }
1.290 +private:
1.291 + int fd;
1.292 + char *buf;
1.293 + size_t size;
1.294 +};
1.295 +#endif
1.296 +
1.297 +void
1.298 +mozilla::ReadAhead(mozilla::filedesc_t aFd, const size_t aOffset,
1.299 + const size_t aCount)
1.300 +{
1.301 +#if defined(XP_WIN)
1.302 +
1.303 + LARGE_INTEGER fpOriginal;
1.304 + LARGE_INTEGER fpOffset;
1.305 +#if defined(HAVE_LONG_LONG)
1.306 + fpOffset.QuadPart = 0;
1.307 +#else
1.308 + fpOffset.u.LowPart = 0;
1.309 + fpOffset.u.HighPart = 0;
1.310 +#endif
1.311 +
1.312 + // Get the current file pointer so that we can restore it. This isn't
1.313 + // really necessary other than to provide the same semantics regarding the
1.314 + // file pointer that other platforms do
1.315 + if (!SetFilePointerEx(aFd, fpOffset, &fpOriginal, FILE_CURRENT)) {
1.316 + return;
1.317 + }
1.318 +
1.319 + if (aOffset) {
1.320 +#if defined(HAVE_LONG_LONG)
1.321 + fpOffset.QuadPart = static_cast<LONGLONG>(aOffset);
1.322 +#else
1.323 + fpOffset.u.LowPart = aOffset;
1.324 + fpOffset.u.HighPart = 0;
1.325 +#endif
1.326 +
1.327 + if (!SetFilePointerEx(aFd, fpOffset, nullptr, FILE_BEGIN)) {
1.328 + return;
1.329 + }
1.330 + }
1.331 +
1.332 + char buf[64 * 1024];
1.333 + size_t totalBytesRead = 0;
1.334 + DWORD dwBytesRead;
1.335 + // Do dummy reads to trigger kernel-side readhead via FILE_FLAG_SEQUENTIAL_SCAN.
1.336 + // Abort when underfilling because during testing the buffers are read fully
1.337 + // A buffer that's not keeping up would imply that readahead isn't working right
1.338 + while (totalBytesRead < aCount &&
1.339 + ReadFile(aFd, buf, sizeof(buf), &dwBytesRead, nullptr) &&
1.340 + dwBytesRead == sizeof(buf)) {
1.341 + totalBytesRead += dwBytesRead;
1.342 + }
1.343 +
1.344 + // Restore the file pointer
1.345 + SetFilePointerEx(aFd, fpOriginal, nullptr, FILE_BEGIN);
1.346 +
1.347 +#elif defined(LINUX) && !defined(ANDROID)
1.348 +
1.349 + readahead(aFd, aOffset, aCount);
1.350 +
1.351 +#elif defined(XP_MACOSX)
1.352 +
1.353 + struct radvisory ra;
1.354 + ra.ra_offset = aOffset;
1.355 + ra.ra_count = aCount;
1.356 + // The F_RDADVISE fcntl is equivalent to Linux' readahead() system call.
1.357 + fcntl(aFd, F_RDADVISE, &ra);
1.358 +
1.359 +#endif
1.360 +}
1.361 +
1.362 +void
1.363 +mozilla::ReadAheadLib(mozilla::pathstr_t aFilePath)
1.364 +{
1.365 + if (!aFilePath) {
1.366 + return;
1.367 + }
1.368 +#if defined(XP_WIN)
1.369 + ReadAheadFile(aFilePath);
1.370 +#elif defined(LINUX) && !defined(ANDROID)
1.371 + int fd = open(aFilePath, O_RDONLY);
1.372 + if (fd < 0) {
1.373 + return;
1.374 + }
1.375 +
1.376 + union {
1.377 + char buf[bufsize];
1.378 + Elf_Ehdr ehdr;
1.379 + } elf;
1.380 + // Read ELF header (ehdr) and program header table (phdr).
1.381 + // We check that the ELF magic is found, that the ELF class matches
1.382 + // our own, and that the program header table as defined in the ELF
1.383 + // headers fits in the buffer we read.
1.384 + if ((read(fd, elf.buf, bufsize) <= 0) ||
1.385 + (memcmp(elf.buf, ELFMAG, 4)) ||
1.386 + (elf.ehdr.e_ident[EI_CLASS] != ELFCLASS) ||
1.387 + (elf.ehdr.e_phoff + elf.ehdr.e_phentsize * elf.ehdr.e_phnum >= bufsize)) {
1.388 + close(fd);
1.389 + return;
1.390 + }
1.391 + // The program header table contains segment definitions. One such
1.392 + // segment type is PT_LOAD, which describes how the dynamic loader
1.393 + // is going to map the file in memory. We use that information to
1.394 + // find the biggest offset from the library that will be mapped in
1.395 + // memory.
1.396 + Elf_Phdr *phdr = (Elf_Phdr *)&elf.buf[elf.ehdr.e_phoff];
1.397 + Elf_Off end = 0;
1.398 + for (int phnum = elf.ehdr.e_phnum; phnum; phdr++, phnum--) {
1.399 + if ((phdr->p_type == PT_LOAD) &&
1.400 + (end < phdr->p_offset + phdr->p_filesz)) {
1.401 + end = phdr->p_offset + phdr->p_filesz;
1.402 + }
1.403 + }
1.404 + // Let the kernel read ahead what the dynamic loader is going to
1.405 + // map in memory soon after.
1.406 + if (end > 0) {
1.407 + ReadAhead(fd, 0, end);
1.408 + }
1.409 + close(fd);
1.410 +#elif defined(XP_MACOSX)
1.411 + ScopedMMap buf(aFilePath);
1.412 + char *base = buf;
1.413 + if (!base) {
1.414 + return;
1.415 + }
1.416 +
1.417 + // An OSX binary might either be a fat (universal) binary or a
1.418 + // Mach-O binary. A fat binary actually embeds several Mach-O
1.419 + // binaries. If we have a fat binary, find the offset where the
1.420 + // Mach-O binary for our CPU type can be found.
1.421 + struct fat_header *fh = (struct fat_header *)base;
1.422 +
1.423 + if (OSSwapBigToHostInt32(fh->magic) == FAT_MAGIC) {
1.424 + uint32_t nfat_arch = OSSwapBigToHostInt32(fh->nfat_arch);
1.425 + struct fat_arch *arch = (struct fat_arch *)&buf[sizeof(struct fat_header)];
1.426 + for (; nfat_arch; arch++, nfat_arch--) {
1.427 + if (OSSwapBigToHostInt32(arch->cputype) == CPU_TYPE) {
1.428 + base += OSSwapBigToHostInt32(arch->offset);
1.429 + break;
1.430 + }
1.431 + }
1.432 + if (base == buf) {
1.433 + return;
1.434 + }
1.435 + }
1.436 +
1.437 + // Check Mach-O magic in the Mach header
1.438 + struct cpu_mach_header *mh = (struct cpu_mach_header *)base;
1.439 + if (mh->magic != MH_MAGIC) {
1.440 + return;
1.441 + }
1.442 +
1.443 + // The Mach header is followed by a sequence of load commands.
1.444 + // Each command has a header containing the command type and the
1.445 + // command size. LD_SEGMENT commands describes how the dynamic
1.446 + // loader is going to map the file in memory. We use that
1.447 + // information to find the biggest offset from the library that
1.448 + // will be mapped in memory.
1.449 + char *cmd = &base[sizeof(struct cpu_mach_header)];
1.450 + uint32_t end = 0;
1.451 + for (uint32_t ncmds = mh->ncmds; ncmds; ncmds--) {
1.452 + struct segment_command *sh = (struct segment_command *)cmd;
1.453 + if (sh->cmd != LC_SEGMENT) {
1.454 + continue;
1.455 + }
1.456 + if (end < sh->fileoff + sh->filesize) {
1.457 + end = sh->fileoff + sh->filesize;
1.458 + }
1.459 + cmd += sh->cmdsize;
1.460 + }
1.461 + // Let the kernel read ahead what the dynamic loader is going to
1.462 + // map in memory soon after.
1.463 + if (end > 0) {
1.464 + ReadAhead(buf.getFd(), base - buf, end);
1.465 + }
1.466 +#endif
1.467 +}
1.468 +
1.469 +void
1.470 +mozilla::ReadAheadFile(mozilla::pathstr_t aFilePath, const size_t aOffset,
1.471 + const size_t aCount, mozilla::filedesc_t* aOutFd)
1.472 +{
1.473 +#if defined(XP_WIN)
1.474 + if (!aFilePath) {
1.475 + if (aOutFd) {
1.476 + *aOutFd = INVALID_HANDLE_VALUE;
1.477 + }
1.478 + return;
1.479 + }
1.480 + HANDLE fd = CreateFileW(aFilePath, GENERIC_READ, FILE_SHARE_READ, nullptr,
1.481 + OPEN_EXISTING, FILE_FLAG_SEQUENTIAL_SCAN, nullptr);
1.482 + if (aOutFd) {
1.483 + *aOutFd = fd;
1.484 + }
1.485 + if (fd == INVALID_HANDLE_VALUE) {
1.486 + return;
1.487 + }
1.488 + ReadAhead(fd, aOffset, aCount);
1.489 + if (!aOutFd) {
1.490 + CloseHandle(fd);
1.491 + }
1.492 +#elif defined(LINUX) && !defined(ANDROID) || defined(XP_MACOSX)
1.493 + if (!aFilePath) {
1.494 + if (aOutFd) {
1.495 + *aOutFd = -1;
1.496 + }
1.497 + return;
1.498 + }
1.499 + int fd = open(aFilePath, O_RDONLY);
1.500 + if (aOutFd) {
1.501 + *aOutFd = fd;
1.502 + }
1.503 + if (fd < 0) {
1.504 + return;
1.505 + }
1.506 + size_t count;
1.507 + if (aCount == SIZE_MAX) {
1.508 + struct stat st;
1.509 + if (fstat(fd, &st) < 0) {
1.510 + if (!aOutFd) {
1.511 + close(fd);
1.512 + }
1.513 + return;
1.514 + }
1.515 + count = st.st_size;
1.516 + } else {
1.517 + count = aCount;
1.518 + }
1.519 + ReadAhead(fd, aOffset, count);
1.520 + if (!aOutFd) {
1.521 + close(fd);
1.522 + }
1.523 +#endif
1.524 +}
1.525 +
