git/run-command.c
Andras Kucsma 05ac8582bc run-command: trigger PATH lookup properly on Cygwin
On Cygwin, the codepath for POSIX-like systems is taken in
run-command.c::start_command(). The prepare_cmd() helper
function is called to decide if the command needs to be looked
up in the PATH. The logic there is to do the PATH-lookup if
and only if it does not have any slash '/' in it. If this test
passes we end up attempting to run the command by appending the
string after each colon-separated component of PATH.

The Cygwin environment supports both Windows and POSIX style
paths, so both forwardslahes '/' and back slashes '\' can be
used as directory separators for any external program the user
supplies.

Examples for path strings which are being incorrectly searched
for in the PATH instead of being executed as is:

- "C:\Program Files\some-program.exe"
- "a\b\c.exe"

To handle these, the PATH lookup detection logic in prepare_cmd()
is taught to know about this Cygwin quirk, by introducing
has_dir_sep(path) helper function to abstract away the difference
between true POSIX and Cygwin systems.

Signed-off-by: Andras Kucsma <r0maikx02b@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27 11:06:17 -07:00

1867 lines
41 KiB
C

#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"
#include "string-list.h"
#include "quote.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_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;
}
static int exists_in_PATH(const char *file)
{
char *r = locate_in_PATH(file);
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 $PATH
* lookups in that case.
*
* The reassignment of EACCES to errno looks like a no-op below,
* but we need to protect against exists_in_PATH overwriting errno.
*/
if (errno == EACCES && !strchr(file, '/'))
errno = exists_in_PATH(file) ? EACCES : ENOENT;
else if (errno == ENOTDIR && !strchr(file, '/'))
errno = ENOENT;
return -1;
}
static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
{
if (!argv[0])
BUG("shell command is empty");
if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
#ifndef GIT_WINDOWS_NATIVE
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 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]);
}
/*
* parent will make it look like the child spewed a fatal error and died
* this is needed to prevent changes to t0061.
*/
static void fake_fatal(const char *err, va_list params)
{
vreportf("fatal: ", err, params);
}
static void child_error_fn(const char *err, va_list params)
{
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, va_list params)
{
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, va_list params)
{
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);
old_errfn = get_error_routine();
set_error_routine(fake_fatal);
errno = cerr->syserr;
switch (cerr->err) {
case CHILD_ERR_CHDIR:
error_errno("exec '%s': cd to '%s' failed",
cmd->argv[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->argv[0]);
break;
case CHILD_ERR_SILENT:
break;
case CHILD_ERR_ERRNO:
error_errno("cannot exec '%s'", cmd->argv[0]);
break;
}
set_error_routine(old_errfn);
}
static int prepare_cmd(struct argv_array *out, const struct child_process *cmd)
{
if (!cmd->argv[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'.
*/
argv_array_push(out, SHELL_PATH);
if (cmd->git_cmd) {
prepare_git_cmd(out, cmd->argv);
} else if (cmd->use_shell) {
prepare_shell_cmd(out, cmd->argv);
} else {
argv_array_pushv(out, cmd->argv);
}
/*
* 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->argv[1])) {
char *program = locate_in_PATH(out->argv[1]);
if (program) {
free((char *)out->argv[1]);
out->argv[1] = program;
} else {
argv_array_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 (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);
} else {
error("waitpid is confused (%s)", argv0);
}
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, ';');
}
/*
* The caller is responsible for initializing cp->env from
* cp->env_array if needed. We only check one place.
*/
if (cp->env)
trace_add_env(&buf, cp->env);
if (cp->git_cmd)
strbuf_addstr(&buf, " git");
sq_quote_argv_pretty(&buf, cp->argv);
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;
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];
}
trace2_child_start(cmd);
trace_run_command(cmd);
fflush(NULL);
#ifndef GIT_WINDOWS_NATIVE
{
int notify_pipe[2];
int null_fd = -1;
char **childenv;
struct argv_array argv = ARGV_ARRAY_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->argv[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 = open("/dev/null", O_RDWR | O_CLOEXEC);
if (null_fd < 0)
die_errno(_("open /dev/null failed"));
set_cloexec(null_fd);
}
childenv = prep_childenv(cmd->env);
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.argv[1], (char *const *) argv.argv + 1,
(char *const *) childenv);
if (errno == ENOEXEC)
execve(argv.argv[0], (char *const *) argv.argv,
(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->argv[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->argv[0], 0);
child_err_spew(cmd, &cerr);
failed_errno = errno;
cmd->pid = -1;
}
close(notify_pipe[0]);
if (null_fd >= 0)
close(null_fd);
argv_array_clear(&argv);
free(childenv);
}
end_of_spawn:
#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, cmd);
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) {
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->argv[0], 0);
trace2_child_exit(cmd, ret);
child_process_clear(cmd);
return ret;
}
int finish_command_in_signal(struct child_process *cmd)
{
int ret = wait_or_whine(cmd->pid, cmd->argv[0], 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);
}
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_tr2(const char **argv, int opt, const char *tr2_class)
{
return run_command_v_opt_cd_env_tr2(argv, opt, NULL, NULL, tr2_class);
}
int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
{
return run_command_v_opt_cd_env_tr2(argv, opt, dir, env, NULL);
}
int run_command_v_opt_cd_env_tr2(const char **argv, int opt, const char *dir,
const char *const *env, const char *tr2_class)
{
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;
cmd.trace2_child_class = tr2_class;
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());
}
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
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
}
int async_with_fork(void)
{
#ifdef NO_PTHREADS
return 1;
#else
return 0;
#endif
}
const char *find_hook(const char *name)
{
static struct strbuf path = STRBUF_INIT;
strbuf_reset(&path);
strbuf_git_path(&path, "hooks/%s", name);
if (access(path.buf, X_OK) < 0) {
int err = errno;
#ifdef STRIP_EXTENSION
strbuf_addstr(&path, STRIP_EXTENSION);
if (access(path.buf, X_OK) >= 0)
return path.buf;
if (errno == EACCES)
err = errno;
#endif
if (err == EACCES && advice_ignored_hook) {
static struct string_list advise_given = STRING_LIST_INIT_DUP;
if (!string_list_lookup(&advise_given, name)) {
string_list_insert(&advise_given, name);
advise(_("The '%s' hook was ignored because "
"it's not set as executable.\n"
"You can disable this warning with "
"`git config advice.ignoredHook false`."),
path.buf);
}
}
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;
hook.trace2_hook_name = name;
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)
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)
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;
}
int run_processes_parallel_tr2(int n, get_next_task_fn get_next_task,
start_failure_fn start_failure,
task_finished_fn task_finished, void *pp_cb,
const char *tr2_category, const char *tr2_label)
{
int result;
trace2_region_enter_printf(tr2_category, tr2_label, NULL, "max:%d",
((n < 1) ? online_cpus() : n));
result = run_processes_parallel(n, get_next_task, start_failure,
task_finished, pp_cb);
trace2_region_leave(tr2_category, tr2_label, NULL);
return result;
}