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Teach run_command how to setup a stdin pipe

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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>
This commit is contained in:
Shawn O. Pearce 2007-03-10 03:28:08 -05:00 committed by Junio C Hamano
parent ebcb5d16ca
commit 4919bf0354
2 changed files with 37 additions and 1 deletions
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35
run-command.c
View File

@ -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 @@ int start_command(struct child_process *cmd)
}
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);

3
run-command.h
View File

@ -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 @@ enum {
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;