Teach run-command about stdout redirection

Some potential callers of the run_command family of functions need
to control not only the stdin redirection of the child, but also
the stdout redirection of the child.  This can now be setup much
like the already existing stdin redirection.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 29 insertions, 1 deletions

diff --git a/run-command.c b/run-command.c
index bef9775e08..d20a6ef80c 100644
--- a/run-command.c
+++ b/run-command.c
@@ -11,7 +11,8 @@ static inline void close_pair(int fd[2])
 int start_command(struct child_process *cmd)
 {
 	int need_in = !cmd->no_stdin && cmd->in < 0;
-	int fdin[2];
+	int need_out = !cmd->stdout_to_stderr && cmd->out < 0;
+	int fdin[2], fdout[2];
 
 	if (need_in) {
 		if (pipe(fdin) < 0)
@@ -20,10 +21,22 @@ int start_command(struct child_process *cmd)
 		cmd->close_in = 1;
 	}
 
+	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;
+	}
+
 	cmd->pid = fork();
 	if (cmd->pid < 0) {
 		if (need_in)
 			close_pair(fdin);
+		if (need_out)
+			close_pair(fdout);
 		return -ERR_RUN_COMMAND_FORK;
 	}
 
@@ -42,6 +55,14 @@ int start_command(struct child_process *cmd)
 
 		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->git_cmd) {
 			execv_git_cmd(cmd->argv);
 		} else {
@@ -55,6 +76,11 @@ int start_command(struct child_process *cmd)
 	else if (cmd->in)
 		close(cmd->in);
 
+	if (need_out)
+		close(fdout[1]);
+	else if (cmd->out > 1)
+		close(cmd->out);
+
 	return 0;
 }
 
@@ -62,6 +88,8 @@ int finish_command(struct child_process *cmd)
 {
 	if (cmd->close_in)
 		close(cmd->in);
+	if (cmd->close_out)
+		close(cmd->out);
 
 	for (;;) {
 		int status, code;