[PATCH 5/8] Teach run_command how to setup a stdin pipe
- From
Shawn O. Pearce <spearce@spearce.org>
- Date
- Mar 10, 2007, 08:28 UTC
- Message-ID
- <20070310082808.GE4133@spearce.org>
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> --- run-command.c | 35 ++++++++++++++++++++++++++++++++++- run-command.h | 3 +++ 2 files changed, 37 insertions(+), 1 deletions(-)
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 @@ 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); 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 @@ 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;
-- 1.5.0.3.942.g299f