The Tor Browser: xpcom/glue/FileUtils.cpp@129ffea94266 (annotated)

xpcom/glue/FileUtils.cpp@129ffea94266 (annotated)

xpcom/glue/FileUtils.cpp

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * 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 (-1 == ret) {
     // OK, perhaps we are too fragmented, allocate non-continuous
     store.fst_flags = F_ALLOCATEALL;
     ret = fcntl(fd, F_PREALLOCATE, &store);
     if (-1 == ret)
       return false;
   }
   return 0 == ftruncate(fd, aLength);
 #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 */
 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:
   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) ||
       (elf.ehdr.e_phoff + 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
 }

The Tor Browser / annotate

xpcom/glue/FileUtils.cpp@129ffea94266 (annotated)

xpcom/glue/FileUtils.cpp