Teach run_command how to setup a stdin pipe
Sometimes callers trying to use run_command to execute a child
process will want to setup a pipe or file descriptor to redirect
into the child's stdin.
This idea is completely stolen from builtin-bundle's fork_with_pipe,
written by Johannes Schindelin. All credit (and blame) should lie
with Dscho. ;-)
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 a866a06..03ff7bc 100644
--- a/run-command.c
+++ b/run-command.c
@@ -4,15 +4,39 @@
int start_command(struct child_process *cmd)
{
+ int need_in = !cmd->no_stdin && cmd->in < 0;
+ int fdin[2];
+
+ if (need_in) {
+ if (pipe(fdin) < 0)
+ return -ERR_RUN_COMMAND_PIPE;
+ cmd->in = fdin[1];
+ cmd->close_in = 1;
+ }
+
cmd->pid = fork();
- if (cmd->pid < 0)
+ if (cmd->pid < 0) {
+ if (need_in) {
+ close(fdin[0]);
+ close(fdin[1]);
+ }
return -ERR_RUN_COMMAND_FORK;
+ }
+
if (!cmd->pid) {
if (cmd->no_stdin) {
int fd = open("/dev/null", O_RDWR);
dup2(fd, 0);
close(fd);
+ } else if (need_in) {
+ dup2(fdin[0], 0);
+ close(fdin[0]);
+ close(fdin[1]);
+ } else if (cmd->in) {
+ dup2(cmd->in, 0);
+ close(cmd->in);
}
+
if (cmd->stdout_to_stderr)
dup2(2, 1);
if (cmd->git_cmd) {
@@ -22,11 +46,20 @@
}
die("exec %s failed.", cmd->argv[0]);
}
+
+ if (need_in)
+ close(fdin[0]);
+ else if (cmd->in)
+ close(cmd->in);
+
return 0;
}
int finish_command(struct child_process *cmd)
{
+ if (cmd->close_in)
+ close(cmd->in);
+
for (;;) {
int status, code;
pid_t waiting = waitpid(cmd->pid, &status, 0);
diff --git a/run-command.h b/run-command.h
index 24cdb4e..ff09067 100644
--- a/run-command.h
+++ b/run-command.h
@@ -4,6 +4,7 @@
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,
@@ -13,6 +14,8 @@
struct child_process {
const char **argv;
pid_t pid;
+ int in;
+ unsigned close_in:1;
unsigned no_stdin:1;
unsigned git_cmd:1; /* if this is to be git sub-command */
unsigned stdout_to_stderr:1;
