git/run-command.c
Elijah Newren 64c8559575 run-command.h: move declarations for run-command.c from cache.h
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-06-21 13:39:53 -07:00

1961 lines
43 KiB
C

#include "git-compat-util.h"
#include "run-command.h"
#include "environment.h"
#include "exec-cmd.h"
#include "gettext.h"
#include "sigchain.h"
#include "strvec.h"
#include "symlinks.h"
#include "thread-utils.h"
#include "strbuf.h"
#include "string-list.h"
#include "trace.h"
#include "trace2.h"
#include "quote.h"
#include "config.h"
#include "packfile.h"
#include "hook.h"
#include "compat/nonblock.h"
#include "alloc.h"
void child_process_init(struct child_process *child)
{
struct child_process blank = CHILD_PROCESS_INIT;
memcpy(child, &blank, sizeof(*child));
}
void child_process_clear(struct child_process *child)
{
strvec_clear(&child->args);
strvec_clear(&child->env);
}
struct child_to_clean {
pid_t pid;
struct child_process *process;
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)
{
struct child_to_clean *children_to_wait_for = NULL;
while (children_to_clean) {
struct child_to_clean *p = children_to_clean;
children_to_clean = p->next;
if (p->process && !in_signal) {
struct child_process *process = p->process;
if (process->clean_on_exit_handler) {
trace_printf(
"trace: run_command: running exit handler for pid %"
PRIuMAX, (uintmax_t)p->pid
);
process->clean_on_exit_handler(process);
}
}
kill(p->pid, sig);
if (p->process && p->process->wait_after_clean) {
p->next = children_to_wait_for;
children_to_wait_for = p;
} else {
if (!in_signal)
free(p);
}
}
while (children_to_wait_for) {
struct child_to_clean *p = children_to_wait_for;
children_to_wait_for = p->next;
while (waitpid(p->pid, NULL, 0) < 0 && errno == EINTR)
; /* spin waiting for process exit or error */
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_process *process)
{
struct child_to_clean *p = xmalloc(sizeof(*p));
p->pid = pid;
p->process = process;
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]);
}
int is_executable(const char *name)
{
struct stat st;
if (stat(name, &st) || /* stat, not lstat */
!S_ISREG(st.st_mode))
return 0;
#if defined(GIT_WINDOWS_NATIVE)
/*
* On Windows there is no executable bit. The file extension
* indicates whether it can be run as an executable, and Git
* has special-handling to detect scripts and launch them
* through the indicated script interpreter. We test for the
* file extension first because virus scanners may make
* it quite expensive to open many files.
*/
if (ends_with(name, ".exe"))
return S_IXUSR;
{
/*
* Now that we know it does not have an executable extension,
* peek into the file instead.
*/
char buf[3] = { 0 };
int n;
int fd = open(name, O_RDONLY);
st.st_mode &= ~S_IXUSR;
if (fd >= 0) {
n = read(fd, buf, 2);
if (n == 2)
/* look for a she-bang */
if (!strcmp(buf, "#!"))
st.st_mode |= S_IXUSR;
close(fd);
}
}
#endif
return st.st_mode & S_IXUSR;
}
/*
* Search $PATH for a command. This emulates the path search that
* execvp would perform, without actually executing the command so it
* can be used before fork() to prepare to run a command using
* execve() or after execvp() to diagnose why it failed.
*
* The caller should ensure that file contains no directory
* separators.
*
* Returns the path to the command, as found in $PATH or NULL if the
* command could not be found. The caller inherits ownership of the memory
* used to store the resultant path.
*
* This should not be used on Windows, where the $PATH search rules
* are more complicated (e.g., a search for "foo" should find
* "foo.exe").
*/
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 (is_executable(buf.buf))
return strbuf_detach(&buf, NULL);
if (!*end)
break;
p = end + 1;
}
strbuf_release(&buf);
return NULL;
}
int exists_in_PATH(const char *command)
{
char *r = locate_in_PATH(command);
int found = r != NULL;
free(r);
return found;
}
int sane_execvp(const char *file, char * const argv[])
{
#ifndef GIT_WINDOWS_NATIVE
/*
* execvp() doesn't return, so we all we can do is tell trace2
* what we are about to do and let it leave a hint in the log
* (unless of course the execvp() fails).
*
* we skip this for Windows because the compat layer already
* has to emulate the execvp() call anyway.
*/
int exec_id = trace2_exec(file, (const char **)argv);
#endif
if (!execvp(file, argv))
return 0; /* cannot happen ;-) */
#ifndef GIT_WINDOWS_NATIVE
{
int ec = errno;
trace2_exec_result(exec_id, ec);
errno = ec;
}
#endif
/*
* 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 $PATH
* lookups in that case.
*
* The reassignment of EACCES to errno looks like a no-op below,
* but we need to protect against exists_in_PATH overwriting errno.
*/
if (errno == EACCES && !strchr(file, '/'))
errno = exists_in_PATH(file) ? EACCES : ENOENT;
else if (errno == ENOTDIR && !strchr(file, '/'))
errno = ENOENT;
return -1;
}
static const char **prepare_shell_cmd(struct strvec *out, const char **argv)
{
if (!argv[0])
BUG("shell command is empty");
if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
#ifndef GIT_WINDOWS_NATIVE
strvec_push(out, SHELL_PATH);
#else
strvec_push(out, "sh");
#endif
strvec_push(out, "-c");
/*
* If we have no extra arguments, we do not even need to
* bother with the "$@" magic.
*/
if (!argv[1])
strvec_push(out, argv[0]);
else
strvec_pushf(out, "%s \"$@\"", argv[0]);
}
strvec_pushv(out, argv);
return out->v;
}
#ifndef GIT_WINDOWS_NATIVE
static int child_notifier = -1;
enum child_errcode {
CHILD_ERR_CHDIR,
CHILD_ERR_DUP2,
CHILD_ERR_CLOSE,
CHILD_ERR_SIGPROCMASK,
CHILD_ERR_ENOENT,
CHILD_ERR_SILENT,
CHILD_ERR_ERRNO
};
struct child_err {
enum child_errcode err;
int syserr; /* errno */
};
static void child_die(enum child_errcode err)
{
struct child_err buf;
buf.err = err;
buf.syserr = errno;
/* write(2) on buf smaller than PIPE_BUF (min 512) is atomic: */
xwrite(child_notifier, &buf, sizeof(buf));
_exit(1);
}
static void child_dup2(int fd, int to)
{
if (dup2(fd, to) < 0)
child_die(CHILD_ERR_DUP2);
}
static void child_close(int fd)
{
if (close(fd))
child_die(CHILD_ERR_CLOSE);
}
static void child_close_pair(int fd[2])
{
child_close(fd[0]);
child_close(fd[1]);
}
static void child_error_fn(const char *err UNUSED, va_list params UNUSED)
{
const char msg[] = "error() should not be called in child\n";
xwrite(2, msg, sizeof(msg) - 1);
}
static void child_warn_fn(const char *err UNUSED, va_list params UNUSED)
{
const char msg[] = "warn() should not be called in child\n";
xwrite(2, msg, sizeof(msg) - 1);
}
static void NORETURN child_die_fn(const char *err UNUSED, va_list params UNUSED)
{
const char msg[] = "die() should not be called in child\n";
xwrite(2, msg, sizeof(msg) - 1);
_exit(2);
}
/* this runs in the parent process */
static void child_err_spew(struct child_process *cmd, struct child_err *cerr)
{
static void (*old_errfn)(const char *err, va_list params);
report_fn die_message_routine = get_die_message_routine();
old_errfn = get_error_routine();
set_error_routine(die_message_routine);
errno = cerr->syserr;
switch (cerr->err) {
case CHILD_ERR_CHDIR:
error_errno("exec '%s': cd to '%s' failed",
cmd->args.v[0], cmd->dir);
break;
case CHILD_ERR_DUP2:
error_errno("dup2() in child failed");
break;
case CHILD_ERR_CLOSE:
error_errno("close() in child failed");
break;
case CHILD_ERR_SIGPROCMASK:
error_errno("sigprocmask failed restoring signals");
break;
case CHILD_ERR_ENOENT:
error_errno("cannot run %s", cmd->args.v[0]);
break;
case CHILD_ERR_SILENT:
break;
case CHILD_ERR_ERRNO:
error_errno("cannot exec '%s'", cmd->args.v[0]);
break;
}
set_error_routine(old_errfn);
}
static int prepare_cmd(struct strvec *out, const struct child_process *cmd)
{
if (!cmd->args.v[0])
BUG("command is empty");
/*
* Add SHELL_PATH so in the event exec fails with ENOEXEC we can
* attempt to interpret the command with 'sh'.
*/
strvec_push(out, SHELL_PATH);
if (cmd->git_cmd) {
prepare_git_cmd(out, cmd->args.v);
} else if (cmd->use_shell) {
prepare_shell_cmd(out, cmd->args.v);
} else {
strvec_pushv(out, cmd->args.v);
}
/*
* If there are no dir separator characters in the command then perform
* a path lookup and use the resolved path as the command to exec. If
* there are dir separator characters, we have exec attempt to invoke
* the command directly.
*/
if (!has_dir_sep(out->v[1])) {
char *program = locate_in_PATH(out->v[1]);
if (program) {
free((char *)out->v[1]);
out->v[1] = program;
} else {
strvec_clear(out);
errno = ENOENT;
return -1;
}
}
return 0;
}
static char **prep_childenv(const char *const *deltaenv)
{
extern char **environ;
char **childenv;
struct string_list env = STRING_LIST_INIT_DUP;
struct strbuf key = STRBUF_INIT;
const char *const *p;
int i;
/* Construct a sorted string list consisting of the current environ */
for (p = (const char *const *) environ; p && *p; p++) {
const char *equals = strchr(*p, '=');
if (equals) {
strbuf_reset(&key);
strbuf_add(&key, *p, equals - *p);
string_list_append(&env, key.buf)->util = (void *) *p;
} else {
string_list_append(&env, *p)->util = (void *) *p;
}
}
string_list_sort(&env);
/* Merge in 'deltaenv' with the current environ */
for (p = deltaenv; p && *p; p++) {
const char *equals = strchr(*p, '=');
if (equals) {
/* ('key=value'), insert or replace entry */
strbuf_reset(&key);
strbuf_add(&key, *p, equals - *p);
string_list_insert(&env, key.buf)->util = (void *) *p;
} else {
/* otherwise ('key') remove existing entry */
string_list_remove(&env, *p, 0);
}
}
/* Create an array of 'char *' to be used as the childenv */
ALLOC_ARRAY(childenv, env.nr + 1);
for (i = 0; i < env.nr; i++)
childenv[i] = env.items[i].util;
childenv[env.nr] = NULL;
string_list_clear(&env, 0);
strbuf_release(&key);
return childenv;
}
struct atfork_state {
#ifndef NO_PTHREADS
int cs;
#endif
sigset_t old;
};
#define CHECK_BUG(err, msg) \
do { \
int e = (err); \
if (e) \
BUG("%s: %s", msg, strerror(e)); \
} while(0)
static void atfork_prepare(struct atfork_state *as)
{
sigset_t all;
if (sigfillset(&all))
die_errno("sigfillset");
#ifdef NO_PTHREADS
if (sigprocmask(SIG_SETMASK, &all, &as->old))
die_errno("sigprocmask");
#else
CHECK_BUG(pthread_sigmask(SIG_SETMASK, &all, &as->old),
"blocking all signals");
CHECK_BUG(pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &as->cs),
"disabling cancellation");
#endif
}
static void atfork_parent(struct atfork_state *as)
{
#ifdef NO_PTHREADS
if (sigprocmask(SIG_SETMASK, &as->old, NULL))
die_errno("sigprocmask");
#else
CHECK_BUG(pthread_setcancelstate(as->cs, NULL),
"re-enabling cancellation");
CHECK_BUG(pthread_sigmask(SIG_SETMASK, &as->old, NULL),
"restoring signal mask");
#endif
}
#endif /* GIT_WINDOWS_NATIVE */
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 (waiting < 0) {
failed_errno = errno;
if (!in_signal)
error_errno("waitpid for %s failed", argv0);
} else if (waiting != pid) {
if (!in_signal)
error("waitpid is confused (%s)", argv0);
} else if (WIFSIGNALED(status)) {
code = WTERMSIG(status);
if (!in_signal && 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);
} else {
if (!in_signal)
error("waitpid is confused (%s)", argv0);
}
if (!in_signal)
clear_child_for_cleanup(pid);
errno = failed_errno;
return code;
}
static void trace_add_env(struct strbuf *dst, const char *const *deltaenv)
{
struct string_list envs = STRING_LIST_INIT_DUP;
const char *const *e;
int i;
int printed_unset = 0;
/* Last one wins, see run-command.c:prep_childenv() for context */
for (e = deltaenv; e && *e; e++) {
struct strbuf key = STRBUF_INIT;
char *equals = strchr(*e, '=');
if (equals) {
strbuf_add(&key, *e, equals - *e);
string_list_insert(&envs, key.buf)->util = equals + 1;
} else {
string_list_insert(&envs, *e)->util = NULL;
}
strbuf_release(&key);
}
/* "unset X Y...;" */
for (i = 0; i < envs.nr; i++) {
const char *var = envs.items[i].string;
const char *val = envs.items[i].util;
if (val || !getenv(var))
continue;
if (!printed_unset) {
strbuf_addstr(dst, " unset");
printed_unset = 1;
}
strbuf_addf(dst, " %s", var);
}
if (printed_unset)
strbuf_addch(dst, ';');
/* ... followed by "A=B C=D ..." */
for (i = 0; i < envs.nr; i++) {
const char *var = envs.items[i].string;
const char *val = envs.items[i].util;
const char *oldval;
if (!val)
continue;
oldval = getenv(var);
if (oldval && !strcmp(val, oldval))
continue;
strbuf_addf(dst, " %s=", var);
sq_quote_buf_pretty(dst, val);
}
string_list_clear(&envs, 0);
}
static void trace_run_command(const struct child_process *cp)
{
struct strbuf buf = STRBUF_INIT;
if (!trace_want(&trace_default_key))
return;
strbuf_addstr(&buf, "trace: run_command:");
if (cp->dir) {
strbuf_addstr(&buf, " cd ");
sq_quote_buf_pretty(&buf, cp->dir);
strbuf_addch(&buf, ';');
}
trace_add_env(&buf, cp->env.v);
if (cp->git_cmd)
strbuf_addstr(&buf, " git");
sq_quote_argv_pretty(&buf, cp->args.v);
trace_printf("%s", buf.buf);
strbuf_release(&buf);
}
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;
/*
* 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->args.v[0], strerror(failed_errno));
child_process_clear(cmd);
errno = failed_errno;
return -1;
}
cmd->err = fderr[0];
}
trace2_child_start(cmd);
trace_run_command(cmd);
fflush(NULL);
if (cmd->close_object_store)
close_object_store(the_repository->objects);
#ifndef GIT_WINDOWS_NATIVE
{
int notify_pipe[2];
int null_fd = -1;
char **childenv;
struct strvec argv = STRVEC_INIT;
struct child_err cerr;
struct atfork_state as;
if (prepare_cmd(&argv, cmd) < 0) {
failed_errno = errno;
cmd->pid = -1;
if (!cmd->silent_exec_failure)
error_errno("cannot run %s", cmd->args.v[0]);
goto end_of_spawn;
}
if (pipe(notify_pipe))
notify_pipe[0] = notify_pipe[1] = -1;
if (cmd->no_stdin || cmd->no_stdout || cmd->no_stderr) {
null_fd = xopen("/dev/null", O_RDWR | O_CLOEXEC);
set_cloexec(null_fd);
}
childenv = prep_childenv(cmd->env.v);
atfork_prepare(&as);
/*
* NOTE: In order to prevent deadlocking when using threads special
* care should be taken with the function calls made in between the
* fork() and exec() calls. No calls should be made to functions which
* require acquiring a lock (e.g. malloc) as the lock could have been
* held by another thread at the time of forking, causing the lock to
* never be released in the child process. This means only
* Async-Signal-Safe functions are permitted in the child.
*/
cmd->pid = fork();
failed_errno = errno;
if (!cmd->pid) {
int sig;
/*
* Ensure the default die/error/warn routines do not get
* called, they can take stdio locks and malloc.
*/
set_die_routine(child_die_fn);
set_error_routine(child_error_fn);
set_warn_routine(child_warn_fn);
close(notify_pipe[0]);
set_cloexec(notify_pipe[1]);
child_notifier = notify_pipe[1];
if (cmd->no_stdin)
child_dup2(null_fd, 0);
else if (need_in) {
child_dup2(fdin[0], 0);
child_close_pair(fdin);
} else if (cmd->in) {
child_dup2(cmd->in, 0);
child_close(cmd->in);
}
if (cmd->no_stderr)
child_dup2(null_fd, 2);
else if (need_err) {
child_dup2(fderr[1], 2);
child_close_pair(fderr);
} else if (cmd->err > 1) {
child_dup2(cmd->err, 2);
child_close(cmd->err);
}
if (cmd->no_stdout)
child_dup2(null_fd, 1);
else if (cmd->stdout_to_stderr)
child_dup2(2, 1);
else if (need_out) {
child_dup2(fdout[1], 1);
child_close_pair(fdout);
} else if (cmd->out > 1) {
child_dup2(cmd->out, 1);
child_close(cmd->out);
}
if (cmd->dir && chdir(cmd->dir))
child_die(CHILD_ERR_CHDIR);
/*
* restore default signal handlers here, in case
* we catch a signal right before execve below
*/
for (sig = 1; sig < NSIG; sig++) {
/* ignored signals get reset to SIG_DFL on execve */
if (signal(sig, SIG_DFL) == SIG_IGN)
signal(sig, SIG_IGN);
}
if (sigprocmask(SIG_SETMASK, &as.old, NULL) != 0)
child_die(CHILD_ERR_SIGPROCMASK);
/*
* Attempt to exec using the command and arguments starting at
* argv.argv[1]. argv.argv[0] contains SHELL_PATH which will
* be used in the event exec failed with ENOEXEC at which point
* we will try to interpret the command using 'sh'.
*/
execve(argv.v[1], (char *const *) argv.v + 1,
(char *const *) childenv);
if (errno == ENOEXEC)
execve(argv.v[0], (char *const *) argv.v,
(char *const *) childenv);
if (errno == ENOENT) {
if (cmd->silent_exec_failure)
child_die(CHILD_ERR_SILENT);
child_die(CHILD_ERR_ENOENT);
} else {
child_die(CHILD_ERR_ERRNO);
}
}
atfork_parent(&as);
if (cmd->pid < 0)
error_errno("cannot fork() for %s", cmd->args.v[0]);
else if (cmd->clean_on_exit)
mark_child_for_cleanup(cmd->pid, cmd);
/*
* Wait for child's exec. If the exec succeeds (or if fork()
* failed), EOF is seen immediately by the parent. Otherwise, the
* child process sends a child_err struct.
* Note that use of this infrastructure is completely advisory,
* therefore, we keep error checks minimal.
*/
close(notify_pipe[1]);
if (xread(notify_pipe[0], &cerr, sizeof(cerr)) == sizeof(cerr)) {
/*
* At this point we know that fork() succeeded, but exec()
* failed. Errors have been reported to our stderr.
*/
wait_or_whine(cmd->pid, cmd->args.v[0], 0);
child_err_spew(cmd, &cerr);
failed_errno = errno;
cmd->pid = -1;
}
close(notify_pipe[0]);
if (null_fd >= 0)
close(null_fd);
strvec_clear(&argv);
free(childenv);
}
end_of_spawn:
#else
{
int fhin = 0, fhout = 1, fherr = 2;
const char **sargv = cmd->args.v;
struct strvec nargv = STRVEC_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->args.v = prepare_git_cmd(&nargv, sargv);
else if (cmd->use_shell)
cmd->args.v = prepare_shell_cmd(&nargv, sargv);
cmd->pid = mingw_spawnvpe(cmd->args.v[0], cmd->args.v,
(char**) cmd->env.v,
cmd->dir, fhin, fhout, fherr);
failed_errno = errno;
if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
error_errno("cannot spawn %s", cmd->args.v[0]);
if (cmd->clean_on_exit && cmd->pid >= 0)
mark_child_for_cleanup(cmd->pid, cmd);
strvec_clear(&nargv);
cmd->args.v = sargv;
if (fhin != 0)
close(fhin);
if (fhout != 1)
close(fhout);
if (fherr != 2)
close(fherr);
}
#endif
if (cmd->pid < 0) {
trace2_child_exit(cmd, -1);
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->args.v[0], 0);
trace2_child_exit(cmd, ret);
child_process_clear(cmd);
invalidate_lstat_cache();
return ret;
}
int finish_command_in_signal(struct child_process *cmd)
{
int ret = wait_or_whine(cmd->pid, cmd->args.v[0], 1);
if (ret != -1)
trace2_child_exit(cmd, ret);
return ret;
}
int run_command(struct child_process *cmd)
{
int code;
if (cmd->out < 0 || cmd->err < 0)
BUG("run_command with a pipe can cause deadlock");
code = start_command(cmd);
if (code)
return code;
return finish_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)) {
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)
{
report_fn die_message_fn = get_die_message_routine();
die_message_fn(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, &async_die_counter); /* set to any non-NULL valid pointer */
return ret != NULL;
}
int in_async(void)
{
if (!main_thread_set)
return 0; /* no asyncs started yet */
return !pthread_equal(main_thread, pthread_self());
}
static 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;
}
static void NORETURN async_exit(int code)
{
exit(code);
}
#endif
void check_pipe(int err)
{
if (err == EPIPE) {
if (in_async())
async_exit(141);
signal(SIGPIPE, SIG_DFL);
raise(SIGPIPE);
/* Should never happen, but just in case... */
exit(141);
}
}
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, NULL);
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(_("cannot create async thread: %s"), strerror(err));
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
int ret = wait_or_whine(async->pid, "child process", 0);
invalidate_lstat_cache();
return ret;
#else
void *ret = (void *)(intptr_t)(-1);
if (pthread_join(async->tid, &ret))
error("pthread_join failed");
invalidate_lstat_cache();
return (int)(intptr_t)ret;
#endif
}
int async_with_fork(void)
{
#ifdef NO_PTHREADS
return 1;
#else
return 0;
#endif
}
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;
/*
* Don't use xwrite() here. It loops forever on EAGAIN,
* and we're in our own poll() loop here.
*
* Note that we lose xwrite()'s handling of MAX_IO_SIZE
* and EINTR, so we have to implement those ourselves.
*/
len = write(io->fd, io->u.out.buf,
io->u.out.len <= MAX_IO_SIZE ?
io->u.out.len : MAX_IO_SIZE);
if (len < 0) {
if (errno != EINTR && errno != EAGAIN &&
errno != ENOSPC) {
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) {
if (enable_pipe_nonblock(cmd->in) < 0) {
error_errno("unable to make pipe non-blocking");
close(cmd->in);
if (out)
close(cmd->out);
if (err)
close(cmd->err);
return -1;
}
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 {
size_t nr_processes;
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;
size_t output_owner;
struct strbuf buffered_output; /* of finished children */
};
struct parallel_processes_for_signal {
const struct run_process_parallel_opts *opts;
const struct parallel_processes *pp;
};
static void kill_children(const struct parallel_processes *pp,
const struct run_process_parallel_opts *opts,
int signo)
{
for (size_t i = 0; i < opts->processes; i++)
if (pp->children[i].state == GIT_CP_WORKING)
kill(pp->children[i].process.pid, signo);
}
static void kill_children_signal(const struct parallel_processes_for_signal *pp_sig,
int signo)
{
kill_children(pp_sig->pp, pp_sig->opts, signo);
}
static struct parallel_processes_for_signal *pp_for_signal;
static void handle_children_on_signal(int signo)
{
kill_children_signal(pp_for_signal, signo);
sigchain_pop(signo);
raise(signo);
}
static void pp_init(struct parallel_processes *pp,
const struct run_process_parallel_opts *opts,
struct parallel_processes_for_signal *pp_sig)
{
const size_t n = opts->processes;
if (!n)
BUG("you must provide a non-zero number of processes!");
trace_printf("run_processes_parallel: preparing to run up to %"PRIuMAX" tasks",
(uintmax_t)n);
if (!opts->get_next_task)
BUG("you need to specify a get_next_task function");
CALLOC_ARRAY(pp->children, n);
if (!opts->ungroup)
CALLOC_ARRAY(pp->pfd, n);
for (size_t i = 0; i < n; i++) {
strbuf_init(&pp->children[i].err, 0);
child_process_init(&pp->children[i].process);
if (pp->pfd) {
pp->pfd[i].events = POLLIN | POLLHUP;
pp->pfd[i].fd = -1;
}
}
pp_sig->pp = pp;
pp_sig->opts = opts;
pp_for_signal = pp_sig;
sigchain_push_common(handle_children_on_signal);
}
static void pp_cleanup(struct parallel_processes *pp,
const struct run_process_parallel_opts *opts)
{
trace_printf("run_processes_parallel: done");
for (size_t i = 0; i < opts->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,
const struct run_process_parallel_opts *opts)
{
size_t i;
int code;
for (i = 0; i < opts->processes; i++)
if (pp->children[i].state == GIT_CP_FREE)
break;
if (i == opts->processes)
BUG("bookkeeping is hard");
/*
* By default, do not inherit stdin from the parent process - otherwise,
* all children would share stdin! Users may overwrite this to provide
* something to the child's stdin by having their 'get_next_task'
* callback assign 0 to .no_stdin and an appropriate integer to .in.
*/
pp->children[i].process.no_stdin = 1;
code = opts->get_next_task(&pp->children[i].process,
opts->ungroup ? NULL : &pp->children[i].err,
opts->data,
&pp->children[i].data);
if (!code) {
if (!opts->ungroup) {
strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
strbuf_reset(&pp->children[i].err);
}
return 1;
}
if (!opts->ungroup) {
pp->children[i].process.err = -1;
pp->children[i].process.stdout_to_stderr = 1;
}
if (start_command(&pp->children[i].process)) {
if (opts->start_failure)
code = opts->start_failure(opts->ungroup ? NULL :
&pp->children[i].err,
opts->data,
pp->children[i].data);
else
code = 0;
if (!opts->ungroup) {
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;
if (pp->pfd)
pp->pfd[i].fd = pp->children[i].process.err;
return 0;
}
static void pp_buffer_stderr(struct parallel_processes *pp,
const struct run_process_parallel_opts *opts,
int output_timeout)
{
while (poll(pp->pfd, opts->processes, output_timeout) < 0) {
if (errno == EINTR)
continue;
pp_cleanup(pp, opts);
die_errno("poll");
}
/* Buffer output from all pipes. */
for (size_t i = 0; i < opts->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(const struct parallel_processes *pp)
{
size_t 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,
const struct run_process_parallel_opts *opts)
{
int code;
size_t i;
int result = 0;
while (pp->nr_processes > 0) {
for (i = 0; i < opts->processes; i++)
if (pp->children[i].state == GIT_CP_WAIT_CLEANUP)
break;
if (i == opts->processes)
break;
code = finish_command(&pp->children[i].process);
if (opts->task_finished)
code = opts->task_finished(code, opts->ungroup ? NULL :
&pp->children[i].err, opts->data,
pp->children[i].data);
else
code = 0;
if (code)
result = code;
if (code < 0)
break;
pp->nr_processes--;
pp->children[i].state = GIT_CP_FREE;
if (pp->pfd)
pp->pfd[i].fd = -1;
child_process_init(&pp->children[i].process);
if (opts->ungroup) {
; /* no strbuf_*() work to do here */
} else if (i != pp->output_owner) {
strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
strbuf_reset(&pp->children[i].err);
} else {
const size_t n = opts->processes;
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;
}
void run_processes_parallel(const struct run_process_parallel_opts *opts)
{
int i, code;
int output_timeout = 100;
int spawn_cap = 4;
struct parallel_processes_for_signal pp_sig;
struct parallel_processes pp = {
.buffered_output = STRBUF_INIT,
};
/* options */
const char *tr2_category = opts->tr2_category;
const char *tr2_label = opts->tr2_label;
const int do_trace2 = tr2_category && tr2_label;
if (do_trace2)
trace2_region_enter_printf(tr2_category, tr2_label, NULL,
"max:%d", opts->processes);
pp_init(&pp, opts, &pp_sig);
while (1) {
for (i = 0;
i < spawn_cap && !pp.shutdown &&
pp.nr_processes < opts->processes;
i++) {
code = pp_start_one(&pp, opts);
if (!code)
continue;
if (code < 0) {
pp.shutdown = 1;
kill_children(&pp, opts, -code);
}
break;
}
if (!pp.nr_processes)
break;
if (opts->ungroup) {
for (size_t i = 0; i < opts->processes; i++)
pp.children[i].state = GIT_CP_WAIT_CLEANUP;
} else {
pp_buffer_stderr(&pp, opts, output_timeout);
pp_output(&pp);
}
code = pp_collect_finished(&pp, opts);
if (code) {
pp.shutdown = 1;
if (code < 0)
kill_children(&pp, opts,-code);
}
}
pp_cleanup(&pp, opts);
if (do_trace2)
trace2_region_leave(tr2_category, tr2_label, NULL);
}
int run_auto_maintenance(int quiet)
{
int enabled;
struct child_process maint = CHILD_PROCESS_INIT;
if (!git_config_get_bool("maintenance.auto", &enabled) &&
!enabled)
return 0;
maint.git_cmd = 1;
maint.close_object_store = 1;
strvec_pushl(&maint.args, "maintenance", "run", "--auto", NULL);
strvec_push(&maint.args, quiet ? "--quiet" : "--no-quiet");
return run_command(&maint);
}
void prepare_other_repo_env(struct strvec *env, const char *new_git_dir)
{
const char * const *var;
for (var = local_repo_env; *var; var++) {
if (strcmp(*var, CONFIG_DATA_ENVIRONMENT) &&
strcmp(*var, CONFIG_COUNT_ENVIRONMENT))
strvec_push(env, *var);
}
strvec_pushf(env, "%s=%s", GIT_DIR_ENVIRONMENT, new_git_dir);
}
enum start_bg_result start_bg_command(struct child_process *cmd,
start_bg_wait_cb *wait_cb,
void *cb_data,
unsigned int timeout_sec)
{
enum start_bg_result sbgr = SBGR_ERROR;
int ret;
int wait_status;
pid_t pid_seen;
time_t time_limit;
/*
* We do not allow clean-on-exit because the child process
* should persist in the background and possibly/probably
* after this process exits. So we don't want to kill the
* child during our atexit routine.
*/
if (cmd->clean_on_exit)
BUG("start_bg_command() does not allow non-zero clean_on_exit");
if (!cmd->trace2_child_class)
cmd->trace2_child_class = "background";
ret = start_command(cmd);
if (ret) {
/*
* We assume that if `start_command()` fails, we
* either get a complete `trace2_child_start() /
* trace2_child_exit()` pair or it fails before the
* `trace2_child_start()` is emitted, so we do not
* need to worry about it here.
*
* We also assume that `start_command()` does not add
* us to the cleanup list. And that it calls
* `child_process_clear()`.
*/
sbgr = SBGR_ERROR;
goto done;
}
time(&time_limit);
time_limit += timeout_sec;
wait:
pid_seen = waitpid(cmd->pid, &wait_status, WNOHANG);
if (!pid_seen) {
/*
* The child is currently running. Ask the callback
* if the child is ready to do work or whether we
* should keep waiting for it to boot up.
*/
ret = (*wait_cb)(cmd, cb_data);
if (!ret) {
/*
* The child is running and "ready".
*/
trace2_child_ready(cmd, "ready");
sbgr = SBGR_READY;
goto done;
} else if (ret > 0) {
/*
* The callback said to give it more time to boot up
* (subject to our timeout limit).
*/
time_t now;
time(&now);
if (now < time_limit)
goto wait;
/*
* Our timeout has expired. We don't try to
* kill the child, but rather let it continue
* (hopefully) trying to startup.
*/
trace2_child_ready(cmd, "timeout");
sbgr = SBGR_TIMEOUT;
goto done;
} else {
/*
* The cb gave up on this child. It is still running,
* but our cb got an error trying to probe it.
*/
trace2_child_ready(cmd, "error");
sbgr = SBGR_CB_ERROR;
goto done;
}
}
else if (pid_seen == cmd->pid) {
int child_code = -1;
/*
* The child started, but exited or was terminated
* before becoming "ready".
*
* We try to match the behavior of `wait_or_whine()`
* WRT the handling of WIFSIGNALED() and WIFEXITED()
* and convert the child's status to a return code for
* tracing purposes and emit the `trace2_child_exit()`
* event.
*
* We do not want the wait_or_whine() error message
* because we will be called by client-side library
* routines.
*/
if (WIFEXITED(wait_status))
child_code = WEXITSTATUS(wait_status);
else if (WIFSIGNALED(wait_status))
child_code = WTERMSIG(wait_status) + 128;
trace2_child_exit(cmd, child_code);
sbgr = SBGR_DIED;
goto done;
}
else if (pid_seen < 0 && errno == EINTR)
goto wait;
trace2_child_exit(cmd, -1);
sbgr = SBGR_ERROR;
done:
child_process_clear(cmd);
invalidate_lstat_cache();
return sbgr;
}