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hush: make "wait %1" work even if the job is dead

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Example script:

	sleep 1 | (sleep 1;exit 3) &
	sleep 2
	echo Zero:$?
	wait %1
	echo Three:$?

function                                             old     new   delta
clean_up_last_dead_job                                 -      24     +24
process_wait_result                                  426     447     +21
builtin_wait                                         285     293      +8
insert_job_into_table                                264     269      +5
builtin_jobs                                          68      73      +5
remove_job_from_table                                 59      57      -2
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/1 up/down: 63/-2)              Total: 61 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2017-07-14 19:58:46 +02:00
parent 0c5657e911
commit 2ed74e25d3
1 changed files with 52 additions and 39 deletions
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91
shell/hush.c
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@ -7237,11 +7237,42 @@ static const char *get_cmdtext(struct pipe *pi)
return pi->cmdtext;
}
static void remove_job_from_table(struct pipe *pi)
{
struct pipe *prev_pipe;
if (pi == G.job_list) {
G.job_list = pi->next;
} else {
prev_pipe = G.job_list;
while (prev_pipe->next != pi)
prev_pipe = prev_pipe->next;
prev_pipe->next = pi->next;
}
G.last_jobid = 0;
if (G.job_list)
G.last_jobid = G.job_list->jobid;
}
static void delete_finished_job(struct pipe *pi)
{
remove_job_from_table(pi);
free_pipe(pi);
}
static void clean_up_last_dead_job(void)
{
if (G.job_list && !G.job_list->alive_cmds)
delete_finished_job(G.job_list);
}
static void insert_job_into_table(struct pipe *pi)
{
struct pipe *job, **jobp;
int i;
clean_up_last_dead_job();
/* Find the end of the list, and find next job ID to use */
i = 0;
jobp = &G.job_list;
@ -7267,30 +7298,6 @@ static void insert_job_into_table(struct pipe *pi)
printf("[%u] %u %s\n", job->jobid, (unsigned)job->cmds[0].pid, job->cmdtext);
G.last_jobid = job->jobid;
}
static void remove_job_from_table(struct pipe *pi)
{
struct pipe *prev_pipe;
if (pi == G.job_list) {
G.job_list = pi->next;
} else {
prev_pipe = G.job_list;
while (prev_pipe->next != pi)
prev_pipe = prev_pipe->next;
prev_pipe->next = pi->next;
}
if (G.job_list)
G.last_jobid = G.job_list->jobid;
else
G.last_jobid = 0;
}
static void delete_finished_job(struct pipe *pi)
{
remove_job_from_table(pi);
free_pipe(pi);
}
#endif /* JOB */
static int job_exited_or_stopped(struct pipe *pi)
@ -7415,14 +7422,22 @@ static int process_wait_result(struct pipe *fg_pipe, pid_t childpid, int status)
pi->cmds[i].pid = 0;
pi->alive_cmds--;
if (!pi->alive_cmds) {
if (G_interactive_fd)
if (G_interactive_fd) {
printf(JOB_STATUS_FORMAT, pi->jobid,
"Done", pi->cmdtext);
delete_finished_job(pi);
//bash deletes finished jobs from job table only in interactive mode, after "jobs" cmd,
//or if pid of a new process matches one of the old ones
//(see cleanup_dead_jobs(), delete_old_job(), J_NOTIFIED in bash source).
//Testcase script: "(exit 3) & sleep 1; wait %1; echo $?" prints 3 in bash.
delete_finished_job(pi);
} else {
/*
* bash deletes finished jobs from job table only in interactive mode,
* after "jobs" cmd, or if pid of a new process matches one of the old ones
* (see cleanup_dead_jobs(), delete_old_job(), J_NOTIFIED in bash source).
* Testcase script: "(exit 3) & sleep 1; wait %1; echo $?" prints 3 in bash.
* We only retain one "dead" job, if it's the single job on the list.
* This covers most of real-world scenarios where this is useful.
*/
if (pi != G.job_list)
delete_finished_job(pi);
}
}
} else {
/* child stopped */
@ -9696,6 +9711,9 @@ static int FAST_FUNC builtin_jobs(char **argv UNUSED_PARAM)
printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
}
clean_up_last_dead_job();
return EXIT_SUCCESS;
}
@ -9939,17 +9957,12 @@ static int FAST_FUNC builtin_wait(char **argv)
wait_pipe = parse_jobspec(*argv);
if (wait_pipe) {
ret = job_exited_or_stopped(wait_pipe);
if (ret < 0)
if (ret < 0) {
ret = wait_for_child_or_signal(wait_pipe, 0);
//bash immediately deletes finished jobs from job table only in interactive mode,
//we _always_ delete them at once. If we'd start keeping some dead jobs, this
//(and more) would be necessary to avoid accumulating dead jobs:
# if 0
else {
if (!wait_pipe->alive_cmds)
delete_finished_job(wait_pipe);
} else {
/* waiting on "last dead job" removes it */
clean_up_last_dead_job();
}
# endif
}
/* else: parse_jobspec() already emitted error msg */
continue;