Commit 08ac6968 authored by Junio C Hamano's avatar Junio C Hamano

Merge branch 'js/run-command-updates'

* js/run-command-updates:
  api-run-command.txt: describe error behavior of run_command functions
  run-command.c: squelch a "use before assignment" warning
  receive-pack: remove unnecessary run_status report
  run_command: report failure to execute the program, but optionally don't
  run_command: encode deadly signal number in the return value
  run_command: report system call errors instead of returning error codes
  run_command: return exit code as positive value
  MinGW: simplify waitpid() emulation macros
parents 0c4f21e4 0b913223
......@@ -35,12 +35,32 @@ Functions
Convenience functions that encapsulate a sequence of
start_command() followed by finish_command(). The argument argv
specifies the program and its arguments. The argument opt is zero
or more of the flags `RUN_COMMAND_NO_STDIN`, `RUN_GIT_CMD`, or
`RUN_COMMAND_STDOUT_TO_STDERR` that correspond to the members
.no_stdin, .git_cmd, .stdout_to_stderr of `struct child_process`.
or more of the flags `RUN_COMMAND_NO_STDIN`, `RUN_GIT_CMD`,
`RUN_COMMAND_STDOUT_TO_STDERR`, or `RUN_SILENT_EXEC_FAILURE`
that correspond to the members .no_stdin, .git_cmd,
.stdout_to_stderr, .silent_exec_failure of `struct child_process`.
The argument dir corresponds the member .dir. The argument env
corresponds to the member .env.
The functions above do the following:
. If a system call failed, errno is set and -1 is returned. A diagnostic
is printed.
. If the program was not found, then -1 is returned and errno is set to
ENOENT; a diagnostic is printed only if .silent_exec_failure is 0.
. Otherwise, the program is run. If it terminates regularly, its exit
code is returned. No diagnistic is printed, even if the exit code is
non-zero.
. If the program terminated due to a signal, then the return value is the
signal number - 128, ie. it is negative and so indicates an unusual
condition; a diagnostic is printed. This return value can be passed to
exit(2), which will report the same code to the parent process that a
POSIX shell's $? would report for a program that died from the signal.
`start_async`::
Run a function asynchronously. Takes a pointer to a `struct
......@@ -143,6 +163,11 @@ string pointers (NULL terminated) in .env:
To specify a new initial working directory for the sub-process,
specify it in the .dir member.
If the program cannot be found, the functions return -1 and set
errno to ENOENT. Normally, an error message is printed, but if
.silent_exec_failure is set to 1, no message is printed for this
special error condition.
* `struct async`
......
......@@ -594,7 +594,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
discard_cache();
if (read_cache() < 0)
die("failed to read the cache");
return -ret;
return ret;
}
}
......
......@@ -123,31 +123,6 @@ static struct command *commands;
static const char pre_receive_hook[] = "hooks/pre-receive";
static const char post_receive_hook[] = "hooks/post-receive";
static int run_status(int code, const char *cmd_name)
{
switch (code) {
case 0:
return 0;
case -ERR_RUN_COMMAND_FORK:
return error("fork of %s failed", cmd_name);
case -ERR_RUN_COMMAND_EXEC:
return error("execute of %s failed", cmd_name);
case -ERR_RUN_COMMAND_PIPE:
return error("pipe failed");
case -ERR_RUN_COMMAND_WAITPID:
return error("waitpid failed");
case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
return error("waitpid is confused");
case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
return error("%s died of signal", cmd_name);
case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
return error("%s died strangely", cmd_name);
default:
error("%s exited with error code %d", cmd_name, -code);
return -code;
}
}
static int run_receive_hook(const char *hook_name)
{
static char buf[sizeof(commands->old_sha1) * 2 + PATH_MAX + 4];
......@@ -174,7 +149,7 @@ static int run_receive_hook(const char *hook_name)
code = start_command(&proc);
if (code)
return run_status(code, hook_name);
return code;
for (cmd = commands; cmd; cmd = cmd->next) {
if (!cmd->error_string) {
size_t n = snprintf(buf, sizeof(buf), "%s %s %s\n",
......@@ -186,7 +161,7 @@ static int run_receive_hook(const char *hook_name)
}
}
close(proc.in);
return run_status(finish_command(&proc), hook_name);
return finish_command(&proc);
}
static int run_update_hook(struct command *cmd)
......@@ -203,9 +178,8 @@ static int run_update_hook(struct command *cmd)
argv[3] = sha1_to_hex(cmd->new_sha1);
argv[4] = NULL;
return run_status(run_command_v_opt(argv, RUN_COMMAND_NO_STDIN |
RUN_COMMAND_STDOUT_TO_STDERR),
update_hook);
return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN |
RUN_COMMAND_STDOUT_TO_STDERR);
}
static int is_ref_checked_out(const char *ref)
......@@ -419,7 +393,6 @@ static void run_update_post_hook(struct command *cmd)
argv[argc] = NULL;
status = run_command_v_opt(argv, RUN_COMMAND_NO_STDIN
| RUN_COMMAND_STDOUT_TO_STDERR);
run_status(status, update_post_hook);
}
static void execute_commands(const char *unpacker_error)
......@@ -537,7 +510,6 @@ static const char *unpack(void)
code = run_command_v_opt(unpacker, RUN_GIT_CMD);
if (!code)
return NULL;
run_status(code, unpacker[0]);
return "unpack-objects abnormal exit";
} else {
const char *keeper[7];
......@@ -563,7 +535,6 @@ static const char *unpack(void)
ip.git_cmd = 1;
status = start_command(&ip);
if (status) {
run_status(status, keeper[0]);
return "index-pack fork failed";
}
pack_lockfile = index_pack_lockfile(ip.out);
......@@ -573,7 +544,6 @@ static const char *unpack(void)
reprepare_packed_git();
return NULL;
}
run_status(status, keeper[0]);
return "index-pack abnormal exit";
}
}
......
......@@ -17,9 +17,10 @@ typedef int pid_t;
#define S_IROTH 0
#define S_IXOTH 0
#define WIFEXITED(x) ((unsigned)(x) < 259) /* STILL_ACTIVE */
#define WIFEXITED(x) 1
#define WIFSIGNALED(x) 0
#define WEXITSTATUS(x) ((x) & 0xff)
#define WIFSIGNALED(x) ((unsigned)(x) > 259)
#define WTERMSIG(x) SIGTERM
#define SIGHUP 1
#define SIGQUIT 3
......
......@@ -267,7 +267,7 @@ static int filter_buffer(int fd, void *data)
status = finish_command(&child_process);
if (status)
error("external filter %s failed %d", params->cmd, -status);
error("external filter %s failed %d", params->cmd, status);
return (write_err || status);
}
......
......@@ -416,13 +416,9 @@ static void execv_dashed_external(const char **argv)
* if we fail because the command is not found, it is
* OK to return. Otherwise, we just pass along the status code.
*/
status = run_command_v_opt(argv, 0);
if (status != -ERR_RUN_COMMAND_EXEC) {
if (IS_RUN_COMMAND_ERR(status))
die("unable to run '%s'", argv[0]);
exit(-status);
}
errno = ENOENT; /* as if we called execvp */
status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE);
if (status >= 0 || errno != ENOENT)
exit(status);
argv[0] = tmp;
......
......@@ -192,10 +192,6 @@ static int ll_ext_merge(const struct ll_merge_driver *fn,
args[2] = cmd.buf;
status = run_command_v_opt(args, 0);
if (status < -ERR_RUN_COMMAND_FORK)
; /* failure in run-command */
else
status = -status;
fd = open(temp[1], O_RDONLY);
if (fd < 0)
goto bad;
......
......@@ -19,6 +19,7 @@ int start_command(struct child_process *cmd)
{
int need_in, need_out, need_err;
int fdin[2], fdout[2], fderr[2];
int failed_errno = failed_errno;
/*
* In case of errors we must keep the promise to close FDs
......@@ -28,9 +29,10 @@ int start_command(struct child_process *cmd)
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);
return -ERR_RUN_COMMAND_PIPE;
goto fail_pipe;
}
cmd->in = fdin[1];
}
......@@ -40,11 +42,12 @@ int start_command(struct child_process *cmd)
&& 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);
return -ERR_RUN_COMMAND_PIPE;
goto fail_pipe;
}
cmd->out = fdout[0];
}
......@@ -52,6 +55,7 @@ int start_command(struct child_process *cmd)
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)
......@@ -60,7 +64,11 @@ int start_command(struct child_process *cmd)
close_pair(fdout);
else if (cmd->out)
close(cmd->out);
return -ERR_RUN_COMMAND_PIPE;
fail_pipe:
error("cannot create pipe for %s: %s",
cmd->argv[0], strerror(failed_errno));
errno = failed_errno;
return -1;
}
cmd->err = fderr[0];
}
......@@ -122,6 +130,9 @@ int start_command(struct child_process *cmd)
strerror(errno));
exit(127);
}
if (cmd->pid < 0)
error("cannot fork() for %s: %s", cmd->argv[0],
strerror(failed_errno = errno));
#else
int s0 = -1, s1 = -1, s2 = -1; /* backups of stdin, stdout, stderr */
const char **sargv = cmd->argv;
......@@ -173,6 +184,9 @@ int start_command(struct child_process *cmd)
}
cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
failed_errno = errno;
if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
if (cmd->env)
free_environ(env);
......@@ -189,7 +203,6 @@ int start_command(struct child_process *cmd)
#endif
if (cmd->pid < 0) {
int err = errno;
if (need_in)
close_pair(fdin);
else if (cmd->in)
......@@ -200,9 +213,8 @@ int start_command(struct child_process *cmd)
close(cmd->out);
if (need_err)
close_pair(fderr);
return err == ENOENT ?
-ERR_RUN_COMMAND_EXEC :
-ERR_RUN_COMMAND_FORK;
errno = failed_errno;
return -1;
}
if (need_in)
......@@ -221,40 +233,51 @@ int start_command(struct child_process *cmd)
return 0;
}
static int wait_or_whine(pid_t pid)
static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
{
for (;;) {
int status, code;
pid_t waiting = waitpid(pid, &status, 0);
if (waiting < 0) {
if (errno == EINTR)
continue;
error("waitpid failed (%s)", strerror(errno));
return -ERR_RUN_COMMAND_WAITPID;
}
if (waiting != pid)
return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
if (WIFSIGNALED(status))
return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
if (!WIFEXITED(status))
return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
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;
error("waitpid for %s failed: %s", argv0, strerror(errno));
} else if (waiting != pid) {
error("waitpid is confused (%s)", argv0);
} else if (WIFSIGNALED(status)) {
code = WTERMSIG(status);
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);
switch (code) {
case 127:
return -ERR_RUN_COMMAND_EXEC;
case 0:
return 0;
default:
return -code;
/*
* Convert special exit code when execvp failed.
*/
if (code == 127) {
code = -1;
failed_errno = ENOENT;
if (!silent_exec_failure)
error("cannot run %s: %s", argv0,
strerror(ENOENT));
}
} else {
error("waitpid is confused (%s)", argv0);
}
errno = failed_errno;
return code;
}
int finish_command(struct child_process *cmd)
{
return wait_or_whine(cmd->pid);
return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
}
int run_command(struct child_process *cmd)
......@@ -274,6 +297,7 @@ static void prepare_run_command_v_opt(struct child_process *cmd,
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;
}
int run_command_v_opt(const char **argv, int opt)
......@@ -338,10 +362,7 @@ int start_async(struct async *async)
int finish_async(struct async *async)
{
#ifndef __MINGW32__
int ret = 0;
if (wait_or_whine(async->pid))
ret = error("waitpid (async) failed");
int ret = wait_or_whine(async->pid, "child process", 0);
#else
DWORD ret = 0;
if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
......@@ -385,15 +406,7 @@ int run_hook(const char *index_file, const char *name, ...)
hook.env = env;
}
ret = start_command(&hook);
ret = run_command(&hook);
free(argv);
if (ret) {
warning("Could not spawn %s", argv[0]);
return ret;
}
ret = finish_command(&hook);
if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
warning("%s exited due to uncaught signal", argv[0]);
return ret;
}
#ifndef RUN_COMMAND_H
#define RUN_COMMAND_H
enum {
ERR_RUN_COMMAND_FORK = 10000,
ERR_RUN_COMMAND_EXEC,
ERR_RUN_COMMAND_PIPE,
ERR_RUN_COMMAND_WAITPID,
ERR_RUN_COMMAND_WAITPID_WRONG_PID,
ERR_RUN_COMMAND_WAITPID_SIGNAL,
ERR_RUN_COMMAND_WAITPID_NOEXIT,
};
#define IS_RUN_COMMAND_ERR(x) (-(x) >= ERR_RUN_COMMAND_FORK)
struct child_process {
const char **argv;
pid_t pid;
......@@ -42,6 +31,7 @@ struct child_process {
unsigned no_stdout:1;
unsigned no_stderr:1;
unsigned git_cmd:1; /* if this is to be git sub-command */
unsigned silent_exec_failure:1;
unsigned stdout_to_stderr:1;
void (*preexec_cb)(void);
};
......@@ -55,6 +45,7 @@ extern int run_hook(const char *index_file, const char *name, ...);
#define RUN_COMMAND_NO_STDIN 1
#define RUN_GIT_CMD 2 /*If this is to be git sub-command */
#define RUN_COMMAND_STDOUT_TO_STDERR 4
#define RUN_SILENT_EXEC_FAILURE 8
int run_command_v_opt(const char **argv, int opt);
/*
......
......@@ -54,7 +54,10 @@ test_expect_success 'upload-pack fails due to error in rev-list' '
! echo "0032want $(git rev-parse HEAD)
0034shallow $(git rev-parse HEAD^)00000009done
0000" | git upload-pack . > /dev/null 2> output.err &&
grep "waitpid (async) failed" output.err
# pack-objects survived
grep "Total.*, reused" output.err &&
# but there was an error, which must have been in rev-list
grep "bad tree object" output.err
'
test_expect_success 'upload-pack fails due to error in pack-objects enumeration' '
......
......@@ -396,7 +396,6 @@ static int curl_transport_push(struct transport *transport, int refspec_nr, cons
{
const char **argv;
int argc;
int err;
if (flags & TRANSPORT_PUSH_MIRROR)
return error("http transport does not support mirror mode");
......@@ -416,20 +415,7 @@ static int curl_transport_push(struct transport *transport, int refspec_nr, cons
while (refspec_nr--)
argv[argc++] = *refspec++;
argv[argc] = NULL;
err = run_command_v_opt(argv, RUN_GIT_CMD);
switch (err) {
case -ERR_RUN_COMMAND_FORK:
error("unable to fork for %s", argv[0]);
case -ERR_RUN_COMMAND_EXEC:
error("unable to exec %s", argv[0]);
break;
case -ERR_RUN_COMMAND_WAITPID:
case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
error("%s died with strange error", argv[0]);
}
return !!err;
return !!run_command_v_opt(argv, RUN_GIT_CMD);
}
static struct ref *get_refs_via_curl(struct transport *transport, int for_push)
......
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