Teach run-command to redirect stdout to /dev/null

Some run-command callers may wish to just discard any data that
is sent to stdout from the child.  This is a lot like our existing
no_stdin support, we just open /dev/null and duplicate the descriptor
into position.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
pull/288/head
Shawn O. Pearce 16 years ago committed by Junio C Hamano
parent f4bba25bdc
commit e4507ae84e
  1. 26
      run-command.c
  2. 1
      run-command.h

@ -8,12 +8,19 @@ static inline void close_pair(int fd[2])
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 = !cmd->no_stdin && cmd->in < 0;
int need_out = !cmd->stdout_to_stderr && cmd->out < 0;
int need_in, need_out;
int fdin[2], fdout[2];
need_in = !cmd->no_stdin && cmd->in < 0;
if (need_in) {
if (pipe(fdin) < 0)
return -ERR_RUN_COMMAND_PIPE;
@ -21,6 +28,9 @@ int start_command(struct child_process *cmd)
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)
@ -41,11 +51,9 @@ int start_command(struct child_process *cmd)
}
if (!cmd->pid) {
if (cmd->no_stdin) {
int fd = open("/dev/null", O_RDWR);
dup2(fd, 0);
close(fd);
} else if (need_in) {
if (cmd->no_stdin)
dup_devnull(0);
else if (need_in) {
dup2(fdin[0], 0);
close_pair(fdin);
} else if (cmd->in) {
@ -53,7 +61,9 @@ int start_command(struct child_process *cmd)
close(cmd->in);
}
if (cmd->stdout_to_stderr)
if (cmd->no_stdout)
dup_devnull(1);
else if (cmd->stdout_to_stderr)
dup2(2, 1);
else if (need_out) {
dup2(fdout[1], 1);

@ -19,6 +19,7 @@ struct child_process {
unsigned close_in:1;
unsigned close_out:1;
unsigned no_stdin:1;
unsigned no_stdout:1;
unsigned git_cmd:1; /* if this is to be git sub-command */
unsigned stdout_to_stderr:1;
};

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