1 files changed, 582 insertions, 0 deletions
diff --git a/xpcom/glue/FileUtils.cpp b/xpcom/glue/FileUtils.cpp
new file mode 100644
index 0000000000..d017d9cea7
--- /dev/null
+++ b/xpcom/glue/FileUtils.cpp
@@ -0,0 +1,582 @@
+/* -*- 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 "mozilla/FileUtils.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#include "nscore.h"
+#include "private/pprio.h"
+#include "prmem.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/MemUtils.h"
+#include "mozilla/BaseProfilerMarkers.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 <nsWindowsHelpers.h>
+#  include <mozilla/NativeNt.h>
+#  include <mozilla/ScopeExit.h>
+#endif
+
+// Functions that are not to be used in standalone glue must be implemented
+// within this #if block
+#if defined(MOZILLA_INTERNAL_API)
+
+#  include "nsString.h"
+
+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;
+}
+
+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
+}
+
+mozilla::PathString mozilla::GetLibraryName(mozilla::pathstr_t aDirectory,
+                                            const char* aLib) {
+#  ifdef XP_WIN
+  nsAutoString fullName;
+  if (aDirectory) {
+    fullName.Assign(aDirectory);
+    fullName.Append('\\');
+  }
+  AppendUTF8toUTF16(MakeStringSpan(aLib), fullName);
+  if (!strstr(aLib, ".dll")) {
+    fullName.AppendLiteral(".dll");
+  }
+  return std::move(fullName);
+#  else
+  char* temp = PR_GetLibraryName(aDirectory, aLib);
+  if (!temp) {
+    return ""_ns;
+  }
+  nsAutoCString libname(temp);
+  PR_FreeLibraryName(temp);
+  return std::move(libname);
+#  endif
+}
+
+mozilla::PathString mozilla::GetLibraryFilePathname(mozilla::pathstr_t aName,
+                                                    PRFuncPtr aAddr) {
+#  ifdef XP_WIN
+  HMODULE handle = GetModuleHandleW(char16ptr_t(aName));
+  if (!handle) {
+    return u""_ns;
+  }
+
+  nsAutoString path;
+  path.SetLength(MAX_PATH);
+  DWORD len = GetModuleFileNameW(handle, char16ptr_t(path.BeginWriting()),
+                                 path.Length());
+  if (!len) {
+    return u""_ns;
+  }
+
+  path.SetLength(len);
+  return std::move(path);
+#  else
+  char* temp = PR_GetLibraryFilePathname(aName, aAddr);
+  if (!temp) {
+    return ""_ns;
+  }
+  nsAutoCString path(temp);
+  PR_Free(temp);  // PR_GetLibraryFilePathname() uses PR_Malloc().
+  return std::move(path);
+#  endif
+}
+
+#endif  // defined(MOZILLA_INTERNAL_API)
+
+#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;
+#  elif defined(__aarch64__)
+static const uint32_t CPU_TYPE = CPU_TYPE_ARM64;
+#  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;
+  }
+
+#ifdef MOZ_GECKO_PROFILER
+#  ifdef XP_WIN
+  auto WideToUTF8 = [](const wchar_t* aStr) -> std::string {
+    std::string s;
+    // Determine the number of output bytes (including null terminator).
+    const int numConv = ::WideCharToMultiByte(CP_UTF8, 0, aStr, -1, nullptr, 0,
+                                              nullptr, nullptr);
+    if (numConv == 0) {
+      return s;
+    }
+    s.resize(numConv);
+    const int numConvd = ::WideCharToMultiByte(CP_UTF8, 0, aStr, -1, s.data(),
+                                               numConv, nullptr, nullptr);
+    if (numConvd != numConv) {
+      // Error during conversion, remove any temporary data.
+      s.clear();
+    }
+    return s;
+  };
+#  endif
+
+  AUTO_BASE_PROFILER_MARKER_TEXT("ReadAheadLib", OTHER, {},
+#  ifdef XP_WIN
+                                 WideToUTF8(aFilePath)
+#  else
+                                 aFilePath
+#  endif
+  );
+#endif
+
+#if defined(XP_WIN)
+  if (!CanPrefetchMemory()) {
+    ReadAheadFile(aFilePath);
+    return;
+  }
+  nsAutoHandle fd(CreateFileW(aFilePath, GENERIC_READ | GENERIC_EXECUTE,
+                              FILE_SHARE_READ, nullptr, OPEN_EXISTING,
+                              FILE_FLAG_SEQUENTIAL_SCAN, nullptr));
+  if (!fd) {
+    return;
+  }
+
+  nsAutoHandle mapping(CreateFileMapping(
+      fd, nullptr, SEC_IMAGE | PAGE_EXECUTE_READ, 0, 0, nullptr));
+  if (!mapping) {
+    return;
+  }
+
+  PVOID data = MapViewOfFile(
+      mapping, FILE_MAP_READ | FILE_MAP_EXECUTE | SEC_IMAGE, 0, 0, 0);
+  if (!data) {
+    return;
+  }
+  auto guard = MakeScopeExit([=]() { UnmapViewOfFile(data); });
+  mozilla::nt::PEHeaders headers(data);
+  Maybe<Span<const uint8_t>> bounds = headers.GetBounds();
+  if (!bounds) {
+    return;
+  }
+
+  PrefetchMemory((uint8_t*)data, bounds->Length());
+
+#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
+}