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>
diff --git a/run-command.c b/run-command.c
index d20a6ef..eff523e 100644
--- a/run-command.c
+++ b/run-command.c
@@ -8,12 +8,19 @@
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 @@
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 @@
}
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 @@
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);
diff --git a/run-command.h b/run-command.h
index 1c9126b..3680ef9 100644
--- a/run-command.h
+++ b/run-command.h
@@ -19,6 +19,7 @@
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;
};
