[PATCH v2 1/4] run-command: add new check_command helper
And persistent_waitpid() to recover the information from the last run.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
---
run-command.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++------
run-command.h | 5 +++++
2 files changed, 52 insertions(+), 6 deletions(-)
Show changes to 2 files +52 −6
run-command.c, run-command.h
diff --git a/run-command.c b/run-command.c
index 07e27ff..b900c6e 100644
--- a/run-command.c
+++ b/run-command.c
@@ -226,14 +226,27 @@ static inline void set_cloexec(int fd)
fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
}
-static int wait_or_whine(pid_t pid, const char *argv0)
+static pid_t persistent_waitpid(struct child_process *cmd, pid_t pid, int *status)
+{
+ pid_t waiting;
+
+ if (cmd->last_status.valid) {
+ *status = cmd->last_status.status;
+ return pid;
+ }
+
+ while ((waiting = waitpid(pid, status, 0)) < 0 && errno == EINTR)
+ ; /* nothing */
+ return waiting;
+}
+
+static int wait_or_whine(struct child_process *cmd, pid_t pid, const char *argv0)
{
int status, code = -1;
pid_t waiting;
int failed_errno = 0;
- while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
- ; /* nothing */
+ waiting = persistent_waitpid(cmd, pid, &status);
if (waiting < 0) {
failed_errno = errno;
@@ -276,6 +289,8 @@ int start_command(struct child_process *cmd)
int failed_errno = failed_errno;
char *str;
+ cmd->last_status.valid = 0;
+
/*
* In case of errors we must keep the promise to close FDs
* that have been passed in via ->in and ->out.
@@ -437,7 +452,7 @@ fail_pipe:
* At this point we know that fork() succeeded, but execvp()
* failed. Errors have been reported to our stderr.
*/
- wait_or_whine(cmd->pid, cmd->argv[0]);
+ wait_or_whine(cmd, cmd->pid, cmd->argv[0]);
failed_errno = errno;
cmd->pid = -1;
}
@@ -542,7 +557,7 @@ fail_pipe:
int finish_command(struct child_process *cmd)
{
- return wait_or_whine(cmd->pid, cmd->argv[0]);
+ return wait_or_whine(cmd, cmd->pid, cmd->argv[0]);
}
int run_command(struct child_process *cmd)
@@ -553,6 +568,32 @@ int run_command(struct child_process *cmd)
return finish_command(cmd);
}
+int check_command(struct child_process *cmd)
+{
+ int status;
+ pid_t waiting;
+
+ if (cmd->last_status.valid)
+ return 0;
+
+ while ((waiting = waitpid(cmd->pid, &status, WNOHANG)) < 0 && errno == EINTR)
+ ; /* nothing */
+
+ if (!waiting)
+ return 1;
+
+ if (waiting == cmd->pid) {
+ cmd->last_status.valid = 1;
+ cmd->last_status.status = status;
+ return 0;
+ }
+
+ if (waiting > 0)
+ die("BUG: waitpid reported a random pid?");
+
+ return 0;
+}
+
static void prepare_run_command_v_opt(struct child_process *cmd,
const char **argv,
int opt)
@@ -729,7 +770,7 @@ error:
int finish_async(struct async *async)
{
#ifdef NO_PTHREADS
- return wait_or_whine(async->pid, "child process");
+ return wait_or_whine(cmd, async->pid, "child process");
#else
void *ret = (void *)(intptr_t)(-1);
diff --git a/run-command.h b/run-command.h
index 221ce33..74a733d 100644
--- a/run-command.h
+++ b/run-command.h
@@ -39,11 +39,16 @@ struct child_process {
unsigned stdout_to_stderr:1;
unsigned use_shell:1;
unsigned clean_on_exit:1;
+ struct last_status {
+ unsigned valid:1;
+ int status;
+ } last_status;
};
int start_command(struct child_process *);
int finish_command(struct child_process *);
int run_command(struct child_process *);
+int check_command(struct child_process *);
extern char *find_hook(const char *name);
extern int run_hook(const char *index_file, const char *name, ...);
--
1.8.2
Felipe Contreras
