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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <limits>
#include <set>
#include "base/command_line.h"
#include "base/compiler_specific.h"
#include "base/debug/stack_trace.h"
#include "base/dir_reader_posix.h"
#include "base/eintr_wrapper.h"
#include "base/logging.h"
#include "base/platform_thread.h"
#include "base/process_util.h"
#include "base/scoped_ptr.h"
#include "base/stringprintf.h"
#include "base/thread_restrictions.h"
#include "base/time.h"
#include "base/waitable_event.h"
#if defined(OS_MACOSX)
#include <crt_externs.h>
#define environ (*_NSGetEnviron())
#else
extern char** environ;
#endif
namespace base {
namespace {
int WaitpidWithTimeout(ProcessHandle handle, int64 wait_milliseconds,
bool* success) {
// This POSIX version of this function only guarantees that we wait no less
// than |wait_milliseconds| for the process to exit. The child process may
// exit sometime before the timeout has ended but we may still block for up
// to 256 milliseconds after the fact.
//
// waitpid() has no direct support on POSIX for specifying a timeout, you can
// either ask it to block indefinitely or return immediately (WNOHANG).
// When a child process terminates a SIGCHLD signal is sent to the parent.
// Catching this signal would involve installing a signal handler which may
// affect other parts of the application and would be difficult to debug.
//
// Our strategy is to call waitpid() once up front to check if the process
// has already exited, otherwise to loop for wait_milliseconds, sleeping for
// at most 256 milliseconds each time using usleep() and then calling
// waitpid(). The amount of time we sleep starts out at 1 milliseconds, and
// we double it every 4 sleep cycles.
//
// usleep() is speced to exit if a signal is received for which a handler
// has been installed. This means that when a SIGCHLD is sent, it will exit
// depending on behavior external to this function.
//
// This function is used primarily for unit tests, if we want to use it in
// the application itself it would probably be best to examine other routes.
int status = -1;
pid_t ret_pid = HANDLE_EINTR(waitpid(handle, &status, WNOHANG));
static const int64 kMaxSleepInMicroseconds = 1 << 18; // ~256 milliseconds.
int64 max_sleep_time_usecs = 1 << 10; // ~1 milliseconds.
int64 double_sleep_time = 0;
// If the process hasn't exited yet, then sleep and try again.
Time wakeup_time = Time::Now() +
TimeDelta::FromMilliseconds(wait_milliseconds);
while (ret_pid == 0) {
Time now = Time::Now();
if (now > wakeup_time)
break;
// Guaranteed to be non-negative!
int64 sleep_time_usecs = (wakeup_time - now).InMicroseconds();
// Sleep for a bit while we wait for the process to finish.
if (sleep_time_usecs > max_sleep_time_usecs)
sleep_time_usecs = max_sleep_time_usecs;
// usleep() will return 0 and set errno to EINTR on receipt of a signal
// such as SIGCHLD.
usleep(sleep_time_usecs);
ret_pid = HANDLE_EINTR(waitpid(handle, &status, WNOHANG));
if ((max_sleep_time_usecs < kMaxSleepInMicroseconds) &&
(double_sleep_time++ % 4 == 0)) {
max_sleep_time_usecs *= 2;
}
}
if (success)
*success = (ret_pid != -1);
return status;
}
void StackDumpSignalHandler(int signal, siginfo_t* info, ucontext_t* context) {
LOG(ERROR) << "Received signal " << signal;
debug::StackTrace().PrintBacktrace();
// TODO(shess): Port to Linux.
#if defined(OS_MACOSX)
// TODO(shess): Port to 64-bit.
#if ARCH_CPU_32_BITS
char buf[1024];
size_t len;
// NOTE: Even |snprintf()| is not on the approved list for signal
// handlers, but buffered I/O is definitely not on the list due to
// potential for |malloc()|.
len = static_cast<size_t>(
snprintf(buf, sizeof(buf),
"ax: %x, bx: %x, cx: %x, dx: %x\n",
context->uc_mcontext->__ss.__eax,
context->uc_mcontext->__ss.__ebx,
context->uc_mcontext->__ss.__ecx,
context->uc_mcontext->__ss.__edx));
write(STDERR_FILENO, buf, std::min(len, sizeof(buf) - 1));
len = static_cast<size_t>(
snprintf(buf, sizeof(buf),
"di: %x, si: %x, bp: %x, sp: %x, ss: %x, flags: %x\n",
context->uc_mcontext->__ss.__edi,
context->uc_mcontext->__ss.__esi,
context->uc_mcontext->__ss.__ebp,
context->uc_mcontext->__ss.__esp,
context->uc_mcontext->__ss.__ss,
context->uc_mcontext->__ss.__eflags));
write(STDERR_FILENO, buf, std::min(len, sizeof(buf) - 1));
len = static_cast<size_t>(
snprintf(buf, sizeof(buf),
"ip: %x, cs: %x, ds: %x, es: %x, fs: %x, gs: %x\n",
context->uc_mcontext->__ss.__eip,
context->uc_mcontext->__ss.__cs,
context->uc_mcontext->__ss.__ds,
context->uc_mcontext->__ss.__es,
context->uc_mcontext->__ss.__fs,
context->uc_mcontext->__ss.__gs));
write(STDERR_FILENO, buf, std::min(len, sizeof(buf) - 1));
#endif // ARCH_CPU_32_BITS
#endif // defined(OS_MACOSX)
_exit(1);
}
void ResetChildSignalHandlersToDefaults() {
// The previous signal handlers are likely to be meaningless in the child's
// context so we reset them to the defaults for now. http://crbug.com/44953
// These signal handlers are setup in browser_main.cc:BrowserMain
signal(SIGTERM, SIG_DFL);
signal(SIGHUP, SIG_DFL);
signal(SIGINT, SIG_DFL);
}
} // anonymous namespace
ProcessId GetCurrentProcId() {
return getpid();
}
ProcessHandle GetCurrentProcessHandle() {
return GetCurrentProcId();
}
bool OpenProcessHandle(ProcessId pid, ProcessHandle* handle) {
// On Posix platforms, process handles are the same as PIDs, so we
// don't need to do anything.
*handle = pid;
return true;
}
bool OpenPrivilegedProcessHandle(ProcessId pid, ProcessHandle* handle) {
// On POSIX permissions are checked for each operation on process,
// not when opening a "handle".
return OpenProcessHandle(pid, handle);
}
bool OpenProcessHandleWithAccess(ProcessId pid,
uint32 access_flags,
ProcessHandle* handle) {
// On POSIX permissions are checked for each operation on process,
// not when opening a "handle".
return OpenProcessHandle(pid, handle);
}
void CloseProcessHandle(ProcessHandle process) {
// See OpenProcessHandle, nothing to do.
return;
}
ProcessId GetProcId(ProcessHandle process) {
return process;
}
// Attempts to kill the process identified by the given process
// entry structure. Ignores specified exit_code; posix can't force that.
// Returns true if this is successful, false otherwise.
bool KillProcess(ProcessHandle process_id, int exit_code, bool wait) {
DCHECK_GT(process_id, 1) << " tried to kill invalid process_id";
if (process_id <= 1)
return false;
static unsigned kMaxSleepMs = 1000;
unsigned sleep_ms = 4;
bool result = kill(process_id, SIGTERM) == 0;
if (result && wait) {
int tries = 60;
// The process may not end immediately due to pending I/O
bool exited = false;
while (tries-- > 0) {
pid_t pid = HANDLE_EINTR(waitpid(process_id, NULL, WNOHANG));
if (pid == process_id) {
exited = true;
break;
}
if (pid == -1) {
if (errno == ECHILD) {
// The wait may fail with ECHILD if another process also waited for
// the same pid, causing the process state to get cleaned up.
exited = true;
break;
}
DPLOG(ERROR) << "Error waiting for process " << process_id;
}
usleep(sleep_ms * 1000);
if (sleep_ms < kMaxSleepMs)
sleep_ms *= 2;
}
// If we're waiting and the child hasn't died by now, force it
// with a SIGKILL.
if (!exited)
result = kill(process_id, SIGKILL) == 0;
}
if (!result)
DPLOG(ERROR) << "Unable to terminate process " << process_id;
return result;
}
bool KillProcessGroup(ProcessHandle process_group_id) {
bool result = kill(-1 * process_group_id, SIGKILL) == 0;
if (!result)
PLOG(ERROR) << "Unable to terminate process group " << process_group_id;
return result;
}
// A class to handle auto-closing of DIR*'s.
class ScopedDIRClose {
public:
inline void operator()(DIR* x) const {
if (x) {
closedir(x);
}
}
};
typedef scoped_ptr_malloc<DIR, ScopedDIRClose> ScopedDIR;
#if defined(OS_LINUX)
static const rlim_t kSystemDefaultMaxFds = 8192;
static const char kFDDir[] = "/proc/self/fd";
#elif defined(OS_MACOSX)
static const rlim_t kSystemDefaultMaxFds = 256;
static const char kFDDir[] = "/dev/fd";
#elif defined(OS_SOLARIS)
static const rlim_t kSystemDefaultMaxFds = 8192;
static const char kFDDir[] = "/dev/fd";
#elif defined(OS_FREEBSD)
static const rlim_t kSystemDefaultMaxFds = 8192;
static const char kFDDir[] = "/dev/fd";
#elif defined(OS_OPENBSD)
static const rlim_t kSystemDefaultMaxFds = 256;
static const char kFDDir[] = "/dev/fd";
#endif
void CloseSuperfluousFds(const base::InjectiveMultimap& saved_mapping) {
// DANGER: no calls to malloc are allowed from now on:
// http://crbug.com/36678
// Get the maximum number of FDs possible.
struct rlimit nofile;
rlim_t max_fds;
if (getrlimit(RLIMIT_NOFILE, &nofile)) {
// getrlimit failed. Take a best guess.
max_fds = kSystemDefaultMaxFds;
DLOG(ERROR) << "getrlimit(RLIMIT_NOFILE) failed: " << errno;
} else {
max_fds = nofile.rlim_cur;
}
if (max_fds > INT_MAX)
max_fds = INT_MAX;
DirReaderPosix fd_dir(kFDDir);
if (!fd_dir.IsValid()) {
// Fallback case: Try every possible fd.
for (rlim_t i = 0; i < max_fds; ++i) {
const int fd = static_cast<int>(i);
if (fd == STDIN_FILENO || fd == STDOUT_FILENO || fd == STDERR_FILENO)
continue;
InjectiveMultimap::const_iterator j;
for (j = saved_mapping.begin(); j != saved_mapping.end(); j++) {
if (fd == j->dest)
break;
}
if (j != saved_mapping.end())
continue;
// Since we're just trying to close anything we can find,
// ignore any error return values of close().
int unused ALLOW_UNUSED = HANDLE_EINTR(close(fd));
}
return;
}
const int dir_fd = fd_dir.fd();
for ( ; fd_dir.Next(); ) {
// Skip . and .. entries.
if (fd_dir.name()[0] == '.')
continue;
char *endptr;
errno = 0;
const long int fd = strtol(fd_dir.name(), &endptr, 10);
if (fd_dir.name()[0] == 0 || *endptr || fd < 0 || errno)
continue;
if (fd == STDIN_FILENO || fd == STDOUT_FILENO || fd == STDERR_FILENO)
continue;
InjectiveMultimap::const_iterator i;
for (i = saved_mapping.begin(); i != saved_mapping.end(); i++) {
if (fd == i->dest)
break;
}
if (i != saved_mapping.end())
continue;
if (fd == dir_fd)
continue;
// When running under Valgrind, Valgrind opens several FDs for its
// own use and will complain if we try to close them. All of
// these FDs are >= |max_fds|, so we can check against that here
// before closing. See https://bugs.kde.org/show_bug.cgi?id=191758
if (fd < static_cast<int>(max_fds)) {
int ret = HANDLE_EINTR(close(fd));
DPCHECK(ret == 0);
}
}
}
char** AlterEnvironment(const environment_vector& changes,
const char* const* const env) {
unsigned count = 0;
unsigned size = 0;
// First assume that all of the current environment will be included.
for (unsigned i = 0; env[i]; i++) {
const char *const pair = env[i];
count++;
size += strlen(pair) + 1 /* terminating NUL */;
}
for (environment_vector::const_iterator
j = changes.begin(); j != changes.end(); j++) {
bool found = false;
const char *pair;
for (unsigned i = 0; env[i]; i++) {
pair = env[i];
const char *const equals = strchr(pair, '=');
if (!equals)
continue;
const unsigned keylen = equals - pair;
if (keylen == j->first.size() &&
memcmp(pair, j->first.data(), keylen) == 0) {
found = true;
break;
}
}
// if found, we'll either be deleting or replacing this element.
if (found) {
count--;
size -= strlen(pair) + 1;
if (j->second.size())
found = false;
}
// if !found, then we have a new element to add.
if (!found && j->second.size() > 0) {
count++;
size += j->first.size() + 1 /* '=' */ + j->second.size() + 1 /* NUL */;
}
}
count++; // for the final NULL
uint8_t *buffer = new uint8_t[sizeof(char*) * count + size];
char **const ret = reinterpret_cast<char**>(buffer);
unsigned k = 0;
char *scratch = reinterpret_cast<char*>(buffer + sizeof(char*) * count);
for (unsigned i = 0; env[i]; i++) {
const char *const pair = env[i];
const char *const equals = strchr(pair, '=');
if (!equals) {
const unsigned len = strlen(pair);
ret[k++] = scratch;
memcpy(scratch, pair, len + 1);
scratch += len + 1;
continue;
}
const unsigned keylen = equals - pair;
bool handled = false;
for (environment_vector::const_iterator
j = changes.begin(); j != changes.end(); j++) {
if (j->first.size() == keylen &&
memcmp(j->first.data(), pair, keylen) == 0) {
if (!j->second.empty()) {
ret[k++] = scratch;
memcpy(scratch, pair, keylen + 1);
scratch += keylen + 1;
memcpy(scratch, j->second.c_str(), j->second.size() + 1);
scratch += j->second.size() + 1;
}
handled = true;
break;
}
}
if (!handled) {
const unsigned len = strlen(pair);
ret[k++] = scratch;
memcpy(scratch, pair, len + 1);
scratch += len + 1;
}
}
// Now handle new elements
for (environment_vector::const_iterator
j = changes.begin(); j != changes.end(); j++) {
if (j->second.size() == 0)
continue;
bool found = false;
for (unsigned i = 0; env[i]; i++) {
const char *const pair = env[i];
const char *const equals = strchr(pair, '=');
if (!equals)
continue;
const unsigned keylen = equals - pair;
if (keylen == j->first.size() &&
memcmp(pair, j->first.data(), keylen) == 0) {
found = true;
break;
}
}
if (!found) {
ret[k++] = scratch;
memcpy(scratch, j->first.data(), j->first.size());
scratch += j->first.size();
*scratch++ = '=';
memcpy(scratch, j->second.c_str(), j->second.size() + 1);
scratch += j->second.size() + 1;
}
}
ret[k] = NULL;
return ret;
}
bool LaunchAppImpl(
const std::vector<std::string>& argv,
const environment_vector& env_changes,
const file_handle_mapping_vector& fds_to_remap,
bool wait,
ProcessHandle* process_handle,
bool start_new_process_group) {
pid_t pid;
InjectiveMultimap fd_shuffle1, fd_shuffle2;
fd_shuffle1.reserve(fds_to_remap.size());
fd_shuffle2.reserve(fds_to_remap.size());
scoped_array<char*> argv_cstr(new char*[argv.size() + 1]);
scoped_array<char*> new_environ(AlterEnvironment(env_changes, environ));
pid = fork();
if (pid < 0)
return false;
if (pid == 0) {
// Child process
if (start_new_process_group) {
// Instead of inheriting the process group ID of the parent, the child
// starts off a new process group with pgid equal to its process ID.
if (setpgid(0, 0) < 0)
return false;
}
#if defined(OS_MACOSX)
RestoreDefaultExceptionHandler();
#endif
ResetChildSignalHandlersToDefaults();
#if 0
// When debugging it can be helpful to check that we really aren't making
// any hidden calls to malloc.
void *malloc_thunk =
reinterpret_cast<void*>(reinterpret_cast<intptr_t>(malloc) & ~4095);
mprotect(malloc_thunk, 4096, PROT_READ | PROT_WRITE | PROT_EXEC);
memset(reinterpret_cast<void*>(malloc), 0xff, 8);
#endif
// DANGER: no calls to malloc are allowed from now on:
// http://crbug.com/36678
for (file_handle_mapping_vector::const_iterator
it = fds_to_remap.begin(); it != fds_to_remap.end(); ++it) {
fd_shuffle1.push_back(InjectionArc(it->first, it->second, false));
fd_shuffle2.push_back(InjectionArc(it->first, it->second, false));
}
environ = new_environ.get();
// Obscure fork() rule: in the child, if you don't end up doing exec*(),
// you call _exit() instead of exit(). This is because _exit() does not
// call any previously-registered (in the parent) exit handlers, which
// might do things like block waiting for threads that don't even exist
// in the child.
// fd_shuffle1 is mutated by this call because it cannot malloc.
if (!ShuffleFileDescriptors(&fd_shuffle1))
_exit(127);
CloseSuperfluousFds(fd_shuffle2);
for (size_t i = 0; i < argv.size(); i++)
argv_cstr[i] = const_cast<char*>(argv[i].c_str());
argv_cstr[argv.size()] = NULL;
execvp(argv_cstr[0], argv_cstr.get());
RAW_LOG(ERROR, "LaunchApp: failed to execvp:");
RAW_LOG(ERROR, argv_cstr[0]);
_exit(127);
} else {
// Parent process
if (wait) {
// While this isn't strictly disk IO, waiting for another process to
// finish is the sort of thing ThreadRestrictions is trying to prevent.
base::ThreadRestrictions::AssertIOAllowed();
pid_t ret = HANDLE_EINTR(waitpid(pid, 0, 0));
DPCHECK(ret > 0);
}
if (process_handle)
*process_handle = pid;
}
return true;
}
bool LaunchApp(
const std::vector<std::string>& argv,
const environment_vector& env_changes,
const file_handle_mapping_vector& fds_to_remap,
bool wait,
ProcessHandle* process_handle) {
return LaunchAppImpl(argv, env_changes, fds_to_remap,
wait, process_handle, false);
}
bool LaunchAppInNewProcessGroup(
const std::vector<std::string>& argv,
const environment_vector& env_changes,
const file_handle_mapping_vector& fds_to_remap,
bool wait,
ProcessHandle* process_handle) {
return LaunchAppImpl(argv, env_changes, fds_to_remap, wait,
process_handle, true);
}
bool LaunchApp(const std::vector<std::string>& argv,
const file_handle_mapping_vector& fds_to_remap,
bool wait, ProcessHandle* process_handle) {
base::environment_vector no_env;
return LaunchApp(argv, no_env, fds_to_remap, wait, process_handle);
}
bool LaunchApp(const CommandLine& cl,
bool wait, bool start_hidden,
ProcessHandle* process_handle) {
file_handle_mapping_vector no_files;
return LaunchApp(cl.argv(), no_files, wait, process_handle);
}
ProcessMetrics::~ProcessMetrics() { }
void EnableTerminationOnHeapCorruption() {
// On POSIX, there nothing to do AFAIK.
}
bool EnableInProcessStackDumping() {
// When running in an application, our code typically expects SIGPIPE
// to be ignored. Therefore, when testing that same code, it should run
// with SIGPIPE ignored as well.
struct sigaction action;
action.sa_handler = SIG_IGN;
action.sa_flags = 0;
sigemptyset(&action.sa_mask);
bool success = (sigaction(SIGPIPE, &action, NULL) == 0);
sig_t handler = reinterpret_cast<sig_t>(&StackDumpSignalHandler);
success &= (signal(SIGILL, handler) != SIG_ERR);
success &= (signal(SIGABRT, handler) != SIG_ERR);
success &= (signal(SIGFPE, handler) != SIG_ERR);
success &= (signal(SIGBUS, handler) != SIG_ERR);
success &= (signal(SIGSEGV, handler) != SIG_ERR);
success &= (signal(SIGSYS, handler) != SIG_ERR);
return success;
}
void RaiseProcessToHighPriority() {
// On POSIX, we don't actually do anything here. We could try to nice() or
// setpriority() or sched_getscheduler, but these all require extra rights.
}
TerminationStatus GetTerminationStatus(ProcessHandle handle, int* exit_code) {
int status = 0;
const pid_t result = HANDLE_EINTR(waitpid(handle, &status, WNOHANG));
if (result == -1) {
PLOG(ERROR) << "waitpid(" << handle << ")";
if (exit_code)
*exit_code = 0;
return TERMINATION_STATUS_NORMAL_TERMINATION;
} else if (result == 0) {
// the child hasn't exited yet.
if (exit_code)
*exit_code = 0;
return TERMINATION_STATUS_STILL_RUNNING;
}
if (exit_code)
*exit_code = status;
if (WIFSIGNALED(status)) {
switch (WTERMSIG(status)) {
case SIGABRT:
case SIGBUS:
case SIGFPE:
case SIGILL:
case SIGSEGV:
return TERMINATION_STATUS_PROCESS_CRASHED;
case SIGINT:
case SIGKILL:
case SIGTERM:
return TERMINATION_STATUS_PROCESS_WAS_KILLED;
default:
break;
}
}
if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
return TERMINATION_STATUS_ABNORMAL_TERMINATION;
return TERMINATION_STATUS_NORMAL_TERMINATION;
}
bool WaitForExitCode(ProcessHandle handle, int* exit_code) {
int status;
if (HANDLE_EINTR(waitpid(handle, &status, 0)) == -1) {
NOTREACHED();
return false;
}
if (WIFEXITED(status)) {
*exit_code = WEXITSTATUS(status);
return true;
}
// If it didn't exit cleanly, it must have been signaled.
DCHECK(WIFSIGNALED(status));
return false;
}
bool WaitForExitCodeWithTimeout(ProcessHandle handle, int* exit_code,
int64 timeout_milliseconds) {
bool waitpid_success = false;
int status = WaitpidWithTimeout(handle, timeout_milliseconds,
&waitpid_success);
if (status == -1)
return false;
if (!waitpid_success)
return false;
if (!WIFEXITED(status))
return false;
if (WIFSIGNALED(status)) {
*exit_code = -1;
return true;
}
*exit_code = WEXITSTATUS(status);
return true;
}
bool WaitForSingleProcess(ProcessHandle handle, int64 wait_milliseconds) {
bool waitpid_success;
int status;
if (wait_milliseconds == base::kNoTimeout)
waitpid_success = (HANDLE_EINTR(waitpid(handle, &status, 0)) != -1);
else
status = WaitpidWithTimeout(handle, wait_milliseconds, &waitpid_success);
if (status != -1) {
DCHECK(waitpid_success);
return WIFEXITED(status);
} else {
return false;
}
}
bool CrashAwareSleep(ProcessHandle handle, int64 wait_milliseconds) {
bool waitpid_success;
int status = WaitpidWithTimeout(handle, wait_milliseconds, &waitpid_success);
if (status != -1) {
DCHECK(waitpid_success);
return !(WIFEXITED(status) || WIFSIGNALED(status));
} else {
// If waitpid returned with an error, then the process doesn't exist
// (which most probably means it didn't exist before our call).
return waitpid_success;
}
}
int64 TimeValToMicroseconds(const struct timeval& tv) {
static const int kMicrosecondsPerSecond = 1000000;
int64 ret = tv.tv_sec; // Avoid (int * int) integer overflow.
ret *= kMicrosecondsPerSecond;
ret += tv.tv_usec;
return ret;
}
// Executes the application specified by |cl| and wait for it to exit. Stores
// the output (stdout) in |output|. If |do_search_path| is set, it searches the
// path for the application; in that case, |envp| must be null, and it will use
// the current environment. If |do_search_path| is false, |cl| should fully
// specify the path of the application, and |envp| will be used as the
// environment. Redirects stderr to /dev/null. Returns true on success
// (application launched and exited cleanly, with exit code indicating success).
static bool GetAppOutputInternal(const CommandLine& cl, char* const envp[],
std::string* output, size_t max_output,
bool do_search_path) {
// Doing a blocking wait for another command to finish counts as IO.
base::ThreadRestrictions::AssertIOAllowed();
int pipe_fd[2];
pid_t pid;
InjectiveMultimap fd_shuffle1, fd_shuffle2;
const std::vector<std::string>& argv = cl.argv();
scoped_array<char*> argv_cstr(new char*[argv.size() + 1]);
fd_shuffle1.reserve(3);
fd_shuffle2.reserve(3);
// Either |do_search_path| should be false or |envp| should be null, but not
// both.
DCHECK(!do_search_path ^ !envp);
if (pipe(pipe_fd) < 0)
return false;
switch (pid = fork()) {
case -1: // error
close(pipe_fd[0]);
close(pipe_fd[1]);
return false;
case 0: // child
{
#if defined(OS_MACOSX)
RestoreDefaultExceptionHandler();
#endif
// DANGER: no calls to malloc are allowed from now on:
// http://crbug.com/36678
// Obscure fork() rule: in the child, if you don't end up doing exec*(),
// you call _exit() instead of exit(). This is because _exit() does not
// call any previously-registered (in the parent) exit handlers, which
// might do things like block waiting for threads that don't even exist
// in the child.
int dev_null = open("/dev/null", O_WRONLY);
if (dev_null < 0)
_exit(127);
fd_shuffle1.push_back(InjectionArc(pipe_fd[1], STDOUT_FILENO, true));
fd_shuffle1.push_back(InjectionArc(dev_null, STDERR_FILENO, true));
fd_shuffle1.push_back(InjectionArc(dev_null, STDIN_FILENO, true));
// Adding another element here? Remeber to increase the argument to
// reserve(), above.
std::copy(fd_shuffle1.begin(), fd_shuffle1.end(),
std::back_inserter(fd_shuffle2));
if (!ShuffleFileDescriptors(&fd_shuffle1))
_exit(127);
CloseSuperfluousFds(fd_shuffle2);
for (size_t i = 0; i < argv.size(); i++)
argv_cstr[i] = const_cast<char*>(argv[i].c_str());
argv_cstr[argv.size()] = NULL;
if (do_search_path)
execvp(argv_cstr[0], argv_cstr.get());
else
execve(argv_cstr[0], argv_cstr.get(), envp);
_exit(127);
}
default: // parent
{
// Close our writing end of pipe now. Otherwise later read would not
// be able to detect end of child's output (in theory we could still
// write to the pipe).
close(pipe_fd[1]);
output->clear();
char buffer[256];
size_t output_buf_left = max_output;
ssize_t bytes_read = 1; // A lie to properly handle |max_output == 0|
// case in the logic below.
while (output_buf_left > 0) {
bytes_read = HANDLE_EINTR(read(pipe_fd[0], buffer,
std::min(output_buf_left, sizeof(buffer))));
if (bytes_read <= 0)
break;
output->append(buffer, bytes_read);
output_buf_left -= static_cast<size_t>(bytes_read);
}
close(pipe_fd[0]);
// Always wait for exit code (even if we know we'll declare success).
int exit_code = EXIT_FAILURE;
bool success = WaitForExitCode(pid, &exit_code);
// If we stopped because we read as much as we wanted, we always declare
// success (because the child may exit due to |SIGPIPE|).
if (output_buf_left || bytes_read <= 0) {
if (!success || exit_code != EXIT_SUCCESS)
return false;
}
return true;
}
}
}
bool GetAppOutput(const CommandLine& cl, std::string* output) {
// Run |execve()| with the current environment and store "unlimited" data.
return GetAppOutputInternal(cl, NULL, output,
std::numeric_limits<std::size_t>::max(), true);
}
// TODO(viettrungluu): Conceivably, we should have a timeout as well, so we
// don't hang if what we're calling hangs.
bool GetAppOutputRestricted(const CommandLine& cl,
std::string* output, size_t max_output) {
// Run |execve()| with the empty environment.
char* const empty_environ = NULL;
return GetAppOutputInternal(cl, &empty_environ, output, max_output, false);
}
bool WaitForProcessesToExit(const FilePath::StringType& executable_name,
int64 wait_milliseconds,
const ProcessFilter* filter) {
bool result = false;
// TODO(port): This is inefficient, but works if there are multiple procs.
// TODO(port): use waitpid to avoid leaving zombies around
base::Time end_time = base::Time::Now() +
base::TimeDelta::FromMilliseconds(wait_milliseconds);
do {
NamedProcessIterator iter(executable_name, filter);
if (!iter.NextProcessEntry()) {
result = true;
break;
}
PlatformThread::Sleep(100);
} while ((base::Time::Now() - end_time) > base::TimeDelta());
return result;
}
bool CleanupProcesses(const FilePath::StringType& executable_name,
int64 wait_milliseconds,
int exit_code,
const ProcessFilter* filter) {
bool exited_cleanly =
WaitForProcessesToExit(executable_name, wait_milliseconds,
filter);
if (!exited_cleanly)
KillProcesses(executable_name, exit_code, filter);
return exited_cleanly;
}
} // namespace base