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#include "cache.h"
#include "run-command.h"
#include "exec_cmd.h"
#include "sigchain.h"
#include "argv-array.h"
#include "thread-utils.h"
#include "strbuf.h"
void child_process_init(struct child_process *child)
{
memset(child, 0, sizeof(*child));
argv_array_init(&child->args);
argv_array_init(&child->env_array);
}
void child_process_clear(struct child_process *child)
{
argv_array_clear(&child->args);
argv_array_clear(&child->env_array);
}
struct child_to_clean {
pid_t pid;
struct child_to_clean *next;
};
static struct child_to_clean *children_to_clean;
static int installed_child_cleanup_handler;
static void cleanup_children(int sig, int in_signal)
{
while (children_to_clean) {
struct child_to_clean *p = children_to_clean;
children_to_clean = p->next;
kill(p->pid, sig);
if (!in_signal)
free(p);
}
}
static void cleanup_children_on_signal(int sig)
{
cleanup_children(sig, 1);
sigchain_pop(sig);
raise(sig);
}
static void cleanup_children_on_exit(void)
{
cleanup_children(SIGTERM, 0);
}
static void mark_child_for_cleanup(pid_t pid)
{
struct child_to_clean *p = xmalloc(sizeof(*p));
p->pid = pid;
p->next = children_to_clean;
children_to_clean = p;
if (!installed_child_cleanup_handler) {
atexit(cleanup_children_on_exit);
sigchain_push_common(cleanup_children_on_signal);
installed_child_cleanup_handler = 1;
}
}
static void clear_child_for_cleanup(pid_t pid)
{
struct child_to_clean **pp;
for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
struct child_to_clean *clean_me = *pp;
if (clean_me->pid == pid) {
*pp = clean_me->next;
free(clean_me);
return;
}
}
}
static inline void close_pair(int fd[2])
{
close(fd[0]);
close(fd[1]);
}
#ifndef GIT_WINDOWS_NATIVE
static inline void dup_devnull(int to)
{
int fd = open("/dev/null", O_RDWR);
if (fd < 0)
die_errno(_("open /dev/null failed"));
if (dup2(fd, to) < 0)
die_errno(_("dup2(%d,%d) failed"), fd, to);
close(fd);
}
#endif
static char *locate_in_PATH(const char *file)
{
const char *p = getenv("PATH");
struct strbuf buf = STRBUF_INIT;
if (!p || !*p)
return NULL;
while (1) {
const char *end = strchrnul(p, ':');
strbuf_reset(&buf);
/* POSIX specifies an empty entry as the current directory. */
if (end != p) {
strbuf_add(&buf, p, end - p);
strbuf_addch(&buf, '/');
}
strbuf_addstr(&buf, file);
if (!access(buf.buf, F_OK))
return strbuf_detach(&buf, NULL);
if (!*end)
break;
p = end + 1;
}
strbuf_release(&buf);
return NULL;
}
static int exists_in_PATH(const char *file)
{
char *r = locate_in_PATH(file);
free(r);
return r != NULL;
}
int sane_execvp(const char *file, char * const argv[])
{
if (!execvp(file, argv))
return 0; /* cannot happen ;-) */
/*
* When a command can't be found because one of the directories
* listed in $PATH is unsearchable, execvp reports EACCES, but
* careful usability testing (read: analysis of occasional bug
* reports) reveals that "No such file or directory" is more
* intuitive.
*
* We avoid commands with "/", because execvp will not do $PATH
* lookups in that case.
*
* The reassignment of EACCES to errno looks like a no-op below,
* but we need to protect against exists_in_PATH overwriting errno.
*/
if (errno == EACCES && !strchr(file, '/'))
errno = exists_in_PATH(file) ? EACCES : ENOENT;
else if (errno == ENOTDIR && !strchr(file, '/'))
errno = ENOENT;
return -1;
}
static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
{
if (!argv[0])
die("BUG: shell command is empty");
if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
#ifndef GIT_WINDOWS_NATIVE
argv_array_push(out, SHELL_PATH);
#else
argv_array_push(out, "sh");
#endif
argv_array_push(out, "-c");
/*
* If we have no extra arguments, we do not even need to
* bother with the "$@" magic.
*/
if (!argv[1])
argv_array_push(out, argv[0]);
else
argv_array_pushf(out, "%s \"$@\"", argv[0]);
}
argv_array_pushv(out, argv);
return out->argv;
}
#ifndef GIT_WINDOWS_NATIVE
static int execv_shell_cmd(const char **argv)
{
struct argv_array nargv = ARGV_ARRAY_INIT;
prepare_shell_cmd(&nargv, argv);
trace_argv_printf(nargv.argv, "trace: exec:");
sane_execvp(nargv.argv[0], (char **)nargv.argv);
argv_array_clear(&nargv);
return -1;
}
#endif
#ifndef GIT_WINDOWS_NATIVE
static int child_notifier = -1;
static void notify_parent(void)
{
/*
* execvp failed. If possible, we'd like to let start_command
* know, so failures like ENOENT can be handled right away; but
* otherwise, finish_command will still report the error.
*/
xwrite(child_notifier, "", 1);
}
#endif
static inline void set_cloexec(int fd)
{
int flags = fcntl(fd, F_GETFD);
if (flags >= 0)
fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
}
static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
{
int status, code = -1;
pid_t waiting;
int failed_errno = 0;
while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
; /* nothing */
if (in_signal)
return 0;
if (waiting < 0) {
failed_errno = errno;
error_errno("waitpid for %s failed", argv0);
} else if (waiting != pid) {
error("waitpid is confused (%s)", argv0);
} else if (WIFSIGNALED(status)) {
code = WTERMSIG(status);
if (code != SIGINT && code != SIGQUIT && code != SIGPIPE)
error("%s died of signal %d", argv0, code);
/*
* This return value is chosen so that code & 0xff
* mimics the exit code that a POSIX shell would report for
* a program that died from this signal.
*/
code += 128;
} else if (WIFEXITED(status)) {
code = WEXITSTATUS(status);
/*
* Convert special exit code when execvp failed.
*/
if (code == 127) {
code = -1;
failed_errno = ENOENT;
}
} else {
error("waitpid is confused (%s)", argv0);
}
clear_child_for_cleanup(pid);
errno = failed_errno;
return code;
}
int start_command(struct child_process *cmd)
{
int need_in, need_out, need_err;
int fdin[2], fdout[2], fderr[2];
int failed_errno;
char *str;
if (!cmd->argv)
cmd->argv = cmd->args.argv;
if (!cmd->env)
cmd->env = cmd->env_array.argv;
/*
* In case of errors we must keep the promise to close FDs
* that have been passed in via ->in and ->out.
*/
need_in = !cmd->no_stdin && cmd->in < 0;
if (need_in) {
if (pipe(fdin) < 0) {
failed_errno = errno;
if (cmd->out > 0)
close(cmd->out);
str = "standard input";
goto fail_pipe;
}
cmd->in = fdin[1];
}
need_out = !cmd->no_stdout
&& !cmd->stdout_to_stderr
&& cmd->out < 0;
if (need_out) {
if (pipe(fdout) < 0) {
failed_errno = errno;
if (need_in)
close_pair(fdin);
else if (cmd->in)
close(cmd->in);
str = "standard output";
goto fail_pipe;
}
cmd->out = fdout[0];
}
need_err = !cmd->no_stderr && cmd->err < 0;
if (need_err) {
if (pipe(fderr) < 0) {
failed_errno = errno;
if (need_in)
close_pair(fdin);
else if (cmd->in)
close(cmd->in);
if (need_out)
close_pair(fdout);
else if (cmd->out)
close(cmd->out);
str = "standard error";
fail_pipe:
error("cannot create %s pipe for %s: %s",
str, cmd->argv[0], strerror(failed_errno));
child_process_clear(cmd);
errno = failed_errno;
return -1;
}
cmd->err = fderr[0];
}
trace_argv_printf(cmd->argv, "trace: run_command:");
fflush(NULL);
#ifndef GIT_WINDOWS_NATIVE
{
int notify_pipe[2];
if (pipe(notify_pipe))
notify_pipe[0] = notify_pipe[1] = -1;
cmd->pid = fork();
failed_errno = errno;
if (!cmd->pid) {
/*
* Redirect the channel to write syscall error messages to
* before redirecting the process's stderr so that all die()
* in subsequent call paths use the parent's stderr.
*/
if (cmd->no_stderr || need_err) {
int child_err = dup(2);
set_cloexec(child_err);
set_error_handle(fdopen(child_err, "w"));
}
close(notify_pipe[0]);
set_cloexec(notify_pipe[1]);
child_notifier = notify_pipe[1];
atexit(notify_parent);
if (cmd->no_stdin)
dup_devnull(0);
else if (need_in) {
dup2(fdin[0], 0);
close_pair(fdin);
} else if (cmd->in) {
dup2(cmd->in, 0);
close(cmd->in);
}
if (cmd->no_stderr)
dup_devnull(2);
else if (need_err) {
dup2(fderr[1], 2);
close_pair(fderr);
} else if (cmd->err > 1) {
dup2(cmd->err, 2);
close(cmd->err);
}
if (cmd->no_stdout)
dup_devnull(1);
else if (cmd->stdout_to_stderr)
dup2(2, 1);
else if (need_out) {
dup2(fdout[1], 1);
close_pair(fdout);
} else if (cmd->out > 1) {
dup2(cmd->out, 1);
close(cmd->out);
}
if (cmd->dir && chdir(cmd->dir))
die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
cmd->dir);
if (cmd->env) {
for (; *cmd->env; cmd->env++) {
if (strchr(*cmd->env, '='))
putenv((char *)*cmd->env);
else
unsetenv(*cmd->env);
}
}
if (cmd->git_cmd)
execv_git_cmd(cmd->argv);
else if (cmd->use_shell)
execv_shell_cmd(cmd->argv);
else
sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
if (errno == ENOENT) {
if (!cmd->silent_exec_failure)
error("cannot run %s: %s", cmd->argv[0],
strerror(ENOENT));
exit(127);
} else {
die_errno("cannot exec '%s'", cmd->argv[0]);
}
}
if (cmd->pid < 0)
error_errno("cannot fork() for %s", cmd->argv[0]);
else if (cmd->clean_on_exit)
mark_child_for_cleanup(cmd->pid);
/*
* Wait for child's execvp. If the execvp succeeds (or if fork()
* failed), EOF is seen immediately by the parent. Otherwise, the
* child process sends a single byte.
* Note that use of this infrastructure is completely advisory,
* therefore, we keep error checks minimal.
*/
close(notify_pipe[1]);
if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
/*
* At this point we know that fork() succeeded, but execvp()
* failed. Errors have been reported to our stderr.
*/
wait_or_whine(cmd->pid, cmd->argv[0], 0);
failed_errno = errno;
cmd->pid = -1;
}
close(notify_pipe[0]);
}
#else
{
int fhin = 0, fhout = 1, fherr = 2;
const char **sargv = cmd->argv;
struct argv_array nargv = ARGV_ARRAY_INIT;
if (cmd->no_stdin)
fhin = open("/dev/null", O_RDWR);
else if (need_in)
fhin = dup(fdin[0]);
else if (cmd->in)
fhin = dup(cmd->in);
if (cmd->no_stderr)
fherr = open("/dev/null", O_RDWR);
else if (need_err)
fherr = dup(fderr[1]);
else if (cmd->err > 2)
fherr = dup(cmd->err);
if (cmd->no_stdout)
fhout = open("/dev/null", O_RDWR);
else if (cmd->stdout_to_stderr)
fhout = dup(fherr);
else if (need_out)
fhout = dup(fdout[1]);
else if (cmd->out > 1)
fhout = dup(cmd->out);
if (cmd->git_cmd)
cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
else if (cmd->use_shell)
cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
cmd->dir, fhin, fhout, fherr);
failed_errno = errno;
if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
error_errno("cannot spawn %s", cmd->argv[0]);
if (cmd->clean_on_exit && cmd->pid >= 0)
mark_child_for_cleanup(cmd->pid);
argv_array_clear(&nargv);
cmd->argv = sargv;
if (fhin != 0)
close(fhin);
if (fhout != 1)
close(fhout);
if (fherr != 2)
close(fherr);
}
#endif
if (cmd->pid < 0) {
if (need_in)
close_pair(fdin);
else if (cmd->in)
close(cmd->in);
if (need_out)
close_pair(fdout);
else if (cmd->out)
close(cmd->out);
if (need_err)
close_pair(fderr);
else if (cmd->err)
close(cmd->err);
child_process_clear(cmd);
errno = failed_errno;
return -1;
}
if (need_in)
close(fdin[0]);
else if (cmd->in)
close(cmd->in);
if (need_out)
close(fdout[1]);
else if (cmd->out)
close(cmd->out);
if (need_err)
close(fderr[1]);
else if (cmd->err)
close(cmd->err);
return 0;
}
int finish_command(struct child_process *cmd)
{
int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
child_process_clear(cmd);
return ret;
}
int finish_command_in_signal(struct child_process *cmd)
{
return wait_or_whine(cmd->pid, cmd->argv[0], 1);
}
int run_command(struct child_process *cmd)
{
int code;
if (cmd->out < 0 || cmd->err < 0)
die("BUG: run_command with a pipe can cause deadlock");
code = start_command(cmd);
if (code)
return code;
return finish_command(cmd);
}
int run_command_v_opt(const char **argv, int opt)
{
return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
}
int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
{
struct child_process cmd = CHILD_PROCESS_INIT;
cmd.argv = argv;
cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
cmd.dir = dir;
cmd.env = env;
return run_command(&cmd);
}
#ifndef NO_PTHREADS
static pthread_t main_thread;
static int main_thread_set;
static pthread_key_t async_key;
static pthread_key_t async_die_counter;
static void *run_thread(void *data)
{
struct async *async = data;
intptr_t ret;
if (async->isolate_sigpipe) {
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, SIGPIPE);
if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
ret = error("unable to block SIGPIPE in async thread");
return (void *)ret;
}
}
pthread_setspecific(async_key, async);
ret = async->proc(async->proc_in, async->proc_out, async->data);
return (void *)ret;
}
static NORETURN void die_async(const char *err, va_list params)
{
vreportf("fatal: ", err, params);
if (in_async()) {
struct async *async = pthread_getspecific(async_key);
if (async->proc_in >= 0)
close(async->proc_in);
if (async->proc_out >= 0)
close(async->proc_out);
pthread_exit((void *)128);
}
exit(128);
}
static int async_die_is_recursing(void)
{
void *ret = pthread_getspecific(async_die_counter);
pthread_setspecific(async_die_counter, (void *)1);
return ret != NULL;
}
int in_async(void)
{
if (!main_thread_set)
return 0; /* no asyncs started yet */
return !pthread_equal(main_thread, pthread_self());
}
void NORETURN async_exit(int code)
{
pthread_exit((void *)(intptr_t)code);
}
#else
static struct {
void (**handlers)(void);
size_t nr;
size_t alloc;
} git_atexit_hdlrs;
static int git_atexit_installed;
static void git_atexit_dispatch(void)
{
size_t i;
for (i=git_atexit_hdlrs.nr ; i ; i--)
git_atexit_hdlrs.handlers[i-1]();
}
static void git_atexit_clear(void)
{
free(git_atexit_hdlrs.handlers);
memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
git_atexit_installed = 0;
}
#undef atexit
int git_atexit(void (*handler)(void))
{
ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
if (!git_atexit_installed) {
if (atexit(&git_atexit_dispatch))
return -1;
git_atexit_installed = 1;
}
return 0;
}
#define atexit git_atexit
static int process_is_async;
int in_async(void)
{
return process_is_async;
}
void NORETURN async_exit(int code)
{
exit(code);
}
#endif
int start_async(struct async *async)
{
int need_in, need_out;
int fdin[2], fdout[2];
int proc_in, proc_out;
need_in = async->in < 0;
if (need_in) {
if (pipe(fdin) < 0) {
if (async->out > 0)
close(async->out);
return error_errno("cannot create pipe");
}
async->in = fdin[1];
}
need_out = async->out < 0;
if (need_out) {
if (pipe(fdout) < 0) {
if (need_in)
close_pair(fdin);
else if (async->in)
close(async->in);
return error_errno("cannot create pipe");
}
async->out = fdout[0];
}
if (need_in)
proc_in = fdin[0];
else if (async->in)
proc_in = async->in;
else
proc_in = -1;
if (need_out)
proc_out = fdout[1];
else if (async->out)
proc_out = async->out;
else
proc_out = -1;
#ifdef NO_PTHREADS
/* Flush stdio before fork() to avoid cloning buffers */
fflush(NULL);
async->pid = fork();
if (async->pid < 0) {
error_errno("fork (async) failed");
goto error;
}
if (!async->pid) {
if (need_in)
close(fdin[1]);
if (need_out)
close(fdout[0]);
git_atexit_clear();
process_is_async = 1;
exit(!!async->proc(proc_in, proc_out, async->data));
}
mark_child_for_cleanup(async->pid);
if (need_in)
close(fdin[0]);
else if (async->in)
close(async->in);
if (need_out)
close(fdout[1]);
else if (async->out)
close(async->out);
#else
if (!main_thread_set) {
/*
* We assume that the first time that start_async is called
* it is from the main thread.
*/
main_thread_set = 1;
main_thread = pthread_self();
pthread_key_create(&async_key, NULL);
pthread_key_create(&async_die_counter, NULL);
set_die_routine(die_async);
set_die_is_recursing_routine(async_die_is_recursing);
}
if (proc_in >= 0)
set_cloexec(proc_in);
if (proc_out >= 0)
set_cloexec(proc_out);
async->proc_in = proc_in;
async->proc_out = proc_out;
{
int err = pthread_create(&async->tid, NULL, run_thread, async);
if (err) {
error_errno("cannot create thread");
goto error;
}
}
#endif
return 0;
error:
if (need_in)
close_pair(fdin);
else if (async->in)
close(async->in);
if (need_out)
close_pair(fdout);
else if (async->out)
close(async->out);
return -1;
}
int finish_async(struct async *async)
{
#ifdef NO_PTHREADS
return wait_or_whine(async->pid, "child process", 0);
#else
void *ret = (void *)(intptr_t)(-1);
if (pthread_join(async->tid, &ret))
error("pthread_join failed");
return (int)(intptr_t)ret;
#endif
}
const char *find_hook(const char *name)
{
static struct strbuf path = STRBUF_INIT;
strbuf_reset(&path);
if (git_hooks_path)
strbuf_addf(&path, "%s/%s", git_hooks_path, name);
else
strbuf_git_path(&path, "hooks/%s", name);
if (access(path.buf, X_OK) < 0)
return NULL;
return path.buf;
}
int run_hook_ve(const char *const *env, const char *name, va_list args)
{
struct child_process hook = CHILD_PROCESS_INIT;
const char *p;
p = find_hook(name);
if (!p)
return 0;
argv_array_push(&hook.args, p);
while ((p = va_arg(args, const char *)))
argv_array_push(&hook.args, p);
hook.env = env;
hook.no_stdin = 1;
hook.stdout_to_stderr = 1;
return run_command(&hook);
}
int run_hook_le(const char *const *env, const char *name, ...)
{
va_list args;
int ret;
va_start(args, name);
ret = run_hook_ve(env, name, args);
va_end(args);
return ret;
}
struct io_pump {
/* initialized by caller */
int fd;
int type; /* POLLOUT or POLLIN */
union {
struct {
const char *buf;
size_t len;
} out;
struct {
struct strbuf *buf;
size_t hint;
} in;
} u;
/* returned by pump_io */
int error; /* 0 for success, otherwise errno */
/* internal use */
struct pollfd *pfd;
};
static int pump_io_round(struct io_pump *slots, int nr, struct pollfd *pfd)
{
int pollsize = 0;
int i;
for (i = 0; i < nr; i++) {
struct io_pump *io = &slots[i];
if (io->fd < 0)
continue;
pfd[pollsize].fd = io->fd;
pfd[pollsize].events = io->type;
io->pfd = &pfd[pollsize++];
}
if (!pollsize)
return 0;
if (poll(pfd, pollsize, -1) < 0) {
if (errno == EINTR)
return 1;
die_errno("poll failed");
}
for (i = 0; i < nr; i++) {
struct io_pump *io = &slots[i];
if (io->fd < 0)
continue;
if (!(io->pfd->revents & (POLLOUT|POLLIN|POLLHUP|POLLERR|POLLNVAL)))
continue;
if (io->type == POLLOUT) {
ssize_t len = xwrite(io->fd,
io->u.out.buf, io->u.out.len);
if (len < 0) {
io->error = errno;
close(io->fd);
io->fd = -1;
} else {
io->u.out.buf += len;
io->u.out.len -= len;
if (!io->u.out.len) {
close(io->fd);
io->fd = -1;
}
}
}
if (io->type == POLLIN) {
ssize_t len = strbuf_read_once(io->u.in.buf,
io->fd, io->u.in.hint);
if (len < 0)
io->error = errno;
if (len <= 0) {
close(io->fd);
io->fd = -1;
}
}
}
return 1;
}
static int pump_io(struct io_pump *slots, int nr)
{
struct pollfd *pfd;
int i;
for (i = 0; i < nr; i++)
slots[i].error = 0;
ALLOC_ARRAY(pfd, nr);
while (pump_io_round(slots, nr, pfd))
; /* nothing */
free(pfd);
/* There may be multiple errno values, so just pick the first. */
for (i = 0; i < nr; i++) {
if (slots[i].error) {
errno = slots[i].error;
return -1;
}
}
return 0;
}
int pipe_command(struct child_process *cmd,
const char *in, size_t in_len,
struct strbuf *out, size_t out_hint,
struct strbuf *err, size_t err_hint)
{
struct io_pump io[3];
int nr = 0;
if (in)
cmd->in = -1;
if (out)
cmd->out = -1;
if (err)
cmd->err = -1;
if (start_command(cmd) < 0)
return -1;
if (in) {
io[nr].fd = cmd->in;
io[nr].type = POLLOUT;
io[nr].u.out.buf = in;
io[nr].u.out.len = in_len;
nr++;
}
if (out) {
io[nr].fd = cmd->out;
io[nr].type = POLLIN;
io[nr].u.in.buf = out;
io[nr].u.in.hint = out_hint;
nr++;
}
if (err) {
io[nr].fd = cmd->err;
io[nr].type = POLLIN;
io[nr].u.in.buf = err;
io[nr].u.in.hint = err_hint;
nr++;
}
if (pump_io(io, nr) < 0) {
finish_command(cmd); /* throw away exit code */
return -1;
}
return finish_command(cmd);
}
enum child_state {
GIT_CP_FREE,
GIT_CP_WORKING,
GIT_CP_WAIT_CLEANUP,
};
struct parallel_processes {
void *data;
int max_processes;
int nr_processes;
get_next_task_fn get_next_task;
start_failure_fn start_failure;
task_finished_fn task_finished;
struct {
enum child_state state;
struct child_process process;
struct strbuf err;
void *data;
} *children;
/*
* The struct pollfd is logically part of *children,
* but the system call expects it as its own array.
*/
struct pollfd *pfd;
unsigned shutdown : 1;
int output_owner;
struct strbuf buffered_output; /* of finished children */
};
static int default_start_failure(struct strbuf *out,
void *pp_cb,
void *pp_task_cb)
{
return 0;
}
static int default_task_finished(int result,
struct strbuf *out,
void *pp_cb,
void *pp_task_cb)
{
return 0;
}
static void kill_children(struct parallel_processes *pp, int signo)
{
int i, n = pp->max_processes;
for (i = 0; i < n; i++)
if (pp->children[i].state == GIT_CP_WORKING)
kill(pp->children[i].process.pid, signo);
}
static struct parallel_processes *pp_for_signal;
static void handle_children_on_signal(int signo)
{
kill_children(pp_for_signal, signo);
sigchain_pop(signo);
raise(signo);
}
static void pp_init(struct parallel_processes *pp,
int n,
get_next_task_fn get_next_task,
start_failure_fn start_failure,
task_finished_fn task_finished,
void *data)
{
int i;
if (n < 1)
n = online_cpus();
pp->max_processes = n;
trace_printf("run_processes_parallel: preparing to run up to %d tasks", n);
pp->data = data;
if (!get_next_task)
die("BUG: you need to specify a get_next_task function");
pp->get_next_task = get_next_task;
pp->start_failure = start_failure ? start_failure : default_start_failure;
pp->task_finished = task_finished ? task_finished : default_task_finished;
pp->nr_processes = 0;
pp->output_owner = 0;
pp->shutdown = 0;
pp->children = xcalloc(n, sizeof(*pp->children));
pp->pfd = xcalloc(n, sizeof(*pp->pfd));
strbuf_init(&pp->buffered_output, 0);
for (i = 0; i < n; i++) {
strbuf_init(&pp->children[i].err, 0);
child_process_init(&pp->children[i].process);
pp->pfd[i].events = POLLIN | POLLHUP;
pp->pfd[i].fd = -1;
}
pp_for_signal = pp;
sigchain_push_common(handle_children_on_signal);
}
static void pp_cleanup(struct parallel_processes *pp)
{
int i;
trace_printf("run_processes_parallel: done");
for (i = 0; i < pp->max_processes; i++) {
strbuf_release(&pp->children[i].err);
child_process_clear(&pp->children[i].process);
}
free(pp->children);
free(pp->pfd);
/*
* When get_next_task added messages to the buffer in its last
* iteration, the buffered output is non empty.
*/
strbuf_write(&pp->buffered_output, stderr);
strbuf_release(&pp->buffered_output);
sigchain_pop_common();
}
/* returns
* 0 if a new task was started.
* 1 if no new jobs was started (get_next_task ran out of work, non critical
* problem with starting a new command)
* <0 no new job was started, user wishes to shutdown early. Use negative code
* to signal the children.
*/
static int pp_start_one(struct parallel_processes *pp)
{
int i, code;
for (i = 0; i < pp->max_processes; i++)
if (pp->children[i].state == GIT_CP_FREE)
break;
if (i == pp->max_processes)
die("BUG: bookkeeping is hard");
code = pp->get_next_task(&pp->children[i].process,
&pp->children[i].err,
pp->data,
&pp->children[i].data);
if (!code) {
strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
strbuf_reset(&pp->children[i].err);
return 1;
}
pp->children[i].process.err = -1;
pp->children[i].process.stdout_to_stderr = 1;
pp->children[i].process.no_stdin = 1;
if (start_command(&pp->children[i].process)) {
code = pp->start_failure(&pp->children[i].err,
pp->data,
&pp->children[i].data);
strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
strbuf_reset(&pp->children[i].err);
if (code)
pp->shutdown = 1;
return code;
}
pp->nr_processes++;
pp->children[i].state = GIT_CP_WORKING;
pp->pfd[i].fd = pp->children[i].process.err;
return 0;
}
static void pp_buffer_stderr(struct parallel_processes *pp, int output_timeout)
{
int i;
while ((i = poll(pp->pfd, pp->max_processes, output_timeout)) < 0) {
if (errno == EINTR)
continue;
pp_cleanup(pp);
die_errno("poll");
}
/* Buffer output from all pipes. */
for (i = 0; i < pp->max_processes; i++) {
if (pp->children[i].state == GIT_CP_WORKING &&
pp->pfd[i].revents & (POLLIN | POLLHUP)) {
int n = strbuf_read_once(&pp->children[i].err,
pp->children[i].process.err, 0);
if (n == 0) {
close(pp->children[i].process.err);
pp->children[i].state = GIT_CP_WAIT_CLEANUP;
} else if (n < 0)
if (errno != EAGAIN)
die_errno("read");
}
}
}
static void pp_output(struct parallel_processes *pp)
{
int i = pp->output_owner;
if (pp->children[i].state == GIT_CP_WORKING &&
pp->children[i].err.len) {
strbuf_write(&pp->children[i].err, stderr);
strbuf_reset(&pp->children[i].err);
}
}
static int pp_collect_finished(struct parallel_processes *pp)
{
int i, code;
int n = pp->max_processes;
int result = 0;
while (pp->nr_processes > 0) {
for (i = 0; i < pp->max_processes; i++)
if (pp->children[i].state == GIT_CP_WAIT_CLEANUP)
break;
if (i == pp->max_processes)
break;
code = finish_command(&pp->children[i].process);
code = pp->task_finished(code,
&pp->children[i].err, pp->data,
&pp->children[i].data);
if (code)
result = code;
if (code < 0)
break;
pp->nr_processes--;
pp->children[i].state = GIT_CP_FREE;
pp->pfd[i].fd = -1;
child_process_init(&pp->children[i].process);
if (i != pp->output_owner) {
strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
strbuf_reset(&pp->children[i].err);
} else {
strbuf_write(&pp->children[i].err, stderr);
strbuf_reset(&pp->children[i].err);
/* Output all other finished child processes */
strbuf_write(&pp->buffered_output, stderr);
strbuf_reset(&pp->buffered_output);
/*
* Pick next process to output live.
* NEEDSWORK:
* For now we pick it randomly by doing a round
* robin. Later we may want to pick the one with
* the most output or the longest or shortest
* running process time.
*/
for (i = 0; i < n; i++)
if (pp->children[(pp->output_owner + i) % n].state == GIT_CP_WORKING)
break;
pp->output_owner = (pp->output_owner + i) % n;
}
}
return result;
}
int run_processes_parallel(int n,
get_next_task_fn get_next_task,
start_failure_fn start_failure,
task_finished_fn task_finished,
void *pp_cb)
{
int i, code;
int output_timeout = 100;
int spawn_cap = 4;
struct parallel_processes pp;
pp_init(&pp, n, get_next_task, start_failure, task_finished, pp_cb);
while (1) {
for (i = 0;
i < spawn_cap && !pp.shutdown &&
pp.nr_processes < pp.max_processes;
i++) {
code = pp_start_one(&pp);
if (!code)
continue;
if (code < 0) {
pp.shutdown = 1;
kill_children(&pp, -code);
}
break;
}
if (!pp.nr_processes)
break;
pp_buffer_stderr(&pp, output_timeout);
pp_output(&pp);
code = pp_collect_finished(&pp);
if (code) {
pp.shutdown = 1;
if (code < 0)
kill_children(&pp, -code);
}
}
pp_cleanup(&pp);
return 0;
}