git/run-command.c
Shawn O. Pearce b73a439759 run-command: Support sending stderr to /dev/null
Some callers may wish to redirect stderr to /dev/null in some
contexts, such as if they are executing a command only to get
the exit status and don't want users to see whatever output it
may produce as a side-effect of computing that exit status.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2007-11-11 17:09:55 -08:00

240 lines
4.6 KiB
C

#include "cache.h"
#include "run-command.h"
#include "exec_cmd.h"
static inline void close_pair(int fd[2])
{
close(fd[0]);
close(fd[1]);
}
static inline void dup_devnull(int to)
{
int fd = open("/dev/null", O_RDWR);
dup2(fd, to);
close(fd);
}
int start_command(struct child_process *cmd)
{
int need_in, need_out, need_err;
int fdin[2], fdout[2], fderr[2];
need_in = !cmd->no_stdin && cmd->in < 0;
if (need_in) {
if (pipe(fdin) < 0)
return -ERR_RUN_COMMAND_PIPE;
cmd->in = fdin[1];
cmd->close_in = 1;
}
need_out = !cmd->no_stdout
&& !cmd->stdout_to_stderr
&& cmd->out < 0;
if (need_out) {
if (pipe(fdout) < 0) {
if (need_in)
close_pair(fdin);
return -ERR_RUN_COMMAND_PIPE;
}
cmd->out = fdout[0];
cmd->close_out = 1;
}
need_err = !cmd->no_stderr && cmd->err < 0;
if (need_err) {
if (pipe(fderr) < 0) {
if (need_in)
close_pair(fdin);
if (need_out)
close_pair(fdout);
return -ERR_RUN_COMMAND_PIPE;
}
cmd->err = fderr[0];
}
cmd->pid = fork();
if (cmd->pid < 0) {
if (need_in)
close_pair(fdin);
if (need_out)
close_pair(fdout);
if (need_err)
close_pair(fderr);
return -ERR_RUN_COMMAND_FORK;
}
if (!cmd->pid) {
if (cmd->no_stdin)
dup_devnull(0);
else if (need_in) {
dup2(fdin[0], 0);
close_pair(fdin);
} else if (cmd->in) {
dup2(cmd->in, 0);
close(cmd->in);
}
if (cmd->no_stdout)
dup_devnull(1);
else if (cmd->stdout_to_stderr)
dup2(2, 1);
else if (need_out) {
dup2(fdout[1], 1);
close_pair(fdout);
} else if (cmd->out > 1) {
dup2(cmd->out, 1);
close(cmd->out);
}
if (cmd->no_stderr)
dup_devnull(2);
else if (need_err) {
dup2(fderr[1], 2);
close_pair(fderr);
}
if (cmd->dir && chdir(cmd->dir))
die("exec %s: cd to %s failed (%s)", cmd->argv[0],
cmd->dir, strerror(errno));
if (cmd->env) {
for (; *cmd->env; cmd->env++) {
if (strchr(*cmd->env, '='))
putenv((char*)*cmd->env);
else
unsetenv(*cmd->env);
}
}
if (cmd->git_cmd) {
execv_git_cmd(cmd->argv);
} else {
execvp(cmd->argv[0], (char *const*) cmd->argv);
}
die("exec %s failed.", cmd->argv[0]);
}
if (need_in)
close(fdin[0]);
else if (cmd->in)
close(cmd->in);
if (need_out)
close(fdout[1]);
else if (cmd->out > 1)
close(cmd->out);
if (need_err)
close(fderr[1]);
return 0;
}
static int wait_or_whine(pid_t pid)
{
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;
code = WEXITSTATUS(status);
if (code)
return -code;
return 0;
}
}
int finish_command(struct child_process *cmd)
{
if (cmd->close_in)
close(cmd->in);
if (cmd->close_out)
close(cmd->out);
return wait_or_whine(cmd->pid);
}
int run_command(struct child_process *cmd)
{
int code = start_command(cmd);
if (code)
return code;
return finish_command(cmd);
}
static void prepare_run_command_v_opt(struct child_process *cmd,
const char **argv,
int opt)
{
memset(cmd, 0, sizeof(*cmd));
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;
}
int run_command_v_opt(const char **argv, int opt)
{
struct child_process cmd;
prepare_run_command_v_opt(&cmd, argv, opt);
return run_command(&cmd);
}
int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
{
struct child_process cmd;
prepare_run_command_v_opt(&cmd, argv, opt);
cmd.dir = dir;
return run_command(&cmd);
}
int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
{
struct child_process cmd;
prepare_run_command_v_opt(&cmd, argv, opt);
cmd.dir = dir;
cmd.env = env;
return run_command(&cmd);
}
int start_async(struct async *async)
{
int pipe_out[2];
if (pipe(pipe_out) < 0)
return error("cannot create pipe: %s", strerror(errno));
async->pid = fork();
if (async->pid < 0) {
error("fork (async) failed: %s", strerror(errno));
close_pair(pipe_out);
return -1;
}
if (!async->pid) {
close(pipe_out[0]);
exit(!!async->proc(pipe_out[1], async->data));
}
async->out = pipe_out[0];
close(pipe_out[1]);
return 0;
}
int finish_async(struct async *async)
{
int ret = 0;
if (wait_or_whine(async->pid))
ret = error("waitpid (async) failed");
return ret;
}