gecko/xpcom/glue/standalone/nsGlueLinkingOSX.cpp
2012-07-30 17:20:58 +03:00

236 lines
7.1 KiB
C++

/* -*- Mode: C++; tab-width: 6; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 "nsGlueLinking.h"
#include "nsXPCOMGlue.h"
#include <mach-o/dyld.h>
#include <sys/param.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#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>
#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 HAVE_64BIT_OS
#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 *file): buf(NULL) {
fd = open(file, O_RDONLY);
if (fd < 0)
return;
struct stat st;
if (fstat(fd, &st) < 0)
return;
size = st.st_size;
buf = (char *)mmap(NULL, 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;
};
static void
preload(const char *file)
{
ScopedMMap buf(file);
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)];
off_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. The F_RDADVISE fcntl is equivalent
// to Linux' readahead() system call.
if (end > 0) {
struct radvisory ra;
ra.ra_offset = (base - buf);
ra.ra_count = end;
fcntl(buf.getFd(), F_RDADVISE, &ra);
}
}
static const mach_header* sXULLibImage;
static void
ReadDependentCB(const char *aDependentLib, bool do_preload)
{
if (do_preload)
preload(aDependentLib);
(void) NSAddImage(aDependentLib,
NSADDIMAGE_OPTION_RETURN_ON_ERROR |
NSADDIMAGE_OPTION_MATCH_FILENAME_BY_INSTALLNAME);
}
static void*
LookupSymbol(const mach_header* aLib, const char* aSymbolName)
{
// Try to use |NSLookupSymbolInImage| since it is faster than searching
// the global symbol table. If we couldn't get a mach_header pointer
// for the XPCOM dylib, then use |NSLookupAndBindSymbol| to search the
// global symbol table (this shouldn't normally happen, unless the user
// has called XPCOMGlueStartup(".") and relies on libxpcom.dylib
// already being loaded).
NSSymbol sym = nullptr;
if (aLib) {
sym = NSLookupSymbolInImage(aLib, aSymbolName,
NSLOOKUPSYMBOLINIMAGE_OPTION_BIND |
NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR);
} else {
if (NSIsSymbolNameDefined(aSymbolName))
sym = NSLookupAndBindSymbol(aSymbolName);
}
if (!sym)
return nullptr;
return NSAddressOfSymbol(sym);
}
nsresult
XPCOMGlueLoad(const char *xpcomFile, GetFrozenFunctionsFunc *func)
{
const mach_header* lib = nullptr;
if (xpcomFile[0] != '.' || xpcomFile[1] != '\0') {
char xpcomDir[PATH_MAX];
if (realpath(xpcomFile, xpcomDir)) {
char *lastSlash = strrchr(xpcomDir, '/');
if (lastSlash) {
*lastSlash = '\0';
XPCOMGlueLoadDependentLibs(xpcomDir, ReadDependentCB);
snprintf(lastSlash, PATH_MAX - strlen(xpcomDir), "/" XUL_DLL);
sXULLibImage = NSAddImage(xpcomDir,
NSADDIMAGE_OPTION_RETURN_ON_ERROR |
NSADDIMAGE_OPTION_WITH_SEARCHING |
NSADDIMAGE_OPTION_MATCH_FILENAME_BY_INSTALLNAME);
}
}
lib = NSAddImage(xpcomFile,
NSADDIMAGE_OPTION_RETURN_ON_ERROR |
NSADDIMAGE_OPTION_WITH_SEARCHING |
NSADDIMAGE_OPTION_MATCH_FILENAME_BY_INSTALLNAME);
if (!lib) {
NSLinkEditErrors linkEditError;
int errorNum;
const char *errorString;
const char *fileName;
NSLinkEditError(&linkEditError, &errorNum, &fileName, &errorString);
fprintf(stderr, "XPCOMGlueLoad error %d:%d for file %s:\n%s\n",
linkEditError, errorNum, fileName, errorString);
}
}
*func = (GetFrozenFunctionsFunc) LookupSymbol(lib, "_NS_GetFrozenFunctions");
return *func ? NS_OK : NS_ERROR_NOT_AVAILABLE;
}
void
XPCOMGlueUnload()
{
// nothing to do, since we cannot unload dylibs on OS X
}
nsresult
XPCOMGlueLoadXULFunctions(const nsDynamicFunctionLoad *symbols)
{
nsresult rv = NS_OK;
while (symbols->functionName) {
char buffer[512];
snprintf(buffer, sizeof(buffer), "_%s", symbols->functionName);
*symbols->function = (NSFuncPtr) LookupSymbol(sXULLibImage, buffer);
if (!*symbols->function)
rv = NS_ERROR_LOSS_OF_SIGNIFICANT_DATA;
++symbols;
}
return rv;
}