From 2ed74e25d354e6958dc86a21aa32c2dacb809bf0 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 14 Jul 2017 19:58:46 +0200 Subject: hush: make "wait %1" work even if the job is dead 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 --- shell/hush.c | 91 ++++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 52 insertions(+), 39 deletions(-) diff --git a/shell/hush.c b/shell/hush.c index af5c26090..b76351fde 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -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; -- cgit v1.2.3