844f99092
Denys Vlasenko
2009-09-23
Subject
ash: fix `trap`
Binary
No binary (build failed)
Architecture & Compiler Flags
—
Build Log
(log yok)
Commit Diff GitHub →
shell/ash.c +54 -3shell/ash_test/ash-signals/savetrap.right +3 -0shell/ash_test/ash-signals/savetrap.tests +6 -0shell/ash_test/ash-signals/signal1.right +5 -5
shell/ash.c+54 -3
| @@ -4553,7 +4553,52 @@ forkchild(struct job *jp, union node *n, int mode) | |
| * Do we do it correctly? */ | |
| closescript(); | |
| - | clear_traps(); |
| + | |
| + | if (mode == FORK_NOJOB /* is it `xxx` ? */ |
| + | && n && n->type == NCMD /* is it single cmd? */ |
| + | /* && n->ncmd.args->type == NARG - always true? */ |
| + | && strcmp(n->ncmd.args->narg.text, "trap") == 0 |
| + | && n->ncmd.args->narg.next == NULL /* "trap" with no arguments */ |
| + | /* && n->ncmd.args->narg.backquote == NULL - do we need to check this? */ |
| + | ) { |
| + | TRACE(("Trap hack\n")); |
| + | /* Awful hack for `trap` or $(trap). |
| + | * |
| + | * http://www.opengroup.org/onlinepubs/009695399/utilities/trap.html |
| + | * contains an example where "trap" is executed in a subshell: |
| + | * |
| + | * save_traps=$(trap) |
| + | * ... |
| + | * eval "$save_traps" |
| + | * |
| + | * Standard does not say that "trap" in subshell shall print |
| + | * parent shell's traps. It only says that its output |
| + | * must have suitable form, but then, in the above example |
| + | * (which is not supposed to be normative), it implies that. |
| + | * |
| + | * bash (and probably other shell) does implement it |
| + | * (traps are reset to defaults, but "trap" still shows them), |
| + | * but as a result, "trap" logic is hopelessly messed up: |
| + | * |
| + | * # trap |
| + | * trap -- 'echo Ho' SIGWINCH <--- we have a handler |
| + | * # (trap) <--- trap is in subshell - no output (correct, traps are reset) |
| + | * # true | trap <--- trap is in subshell - no output (ditto) |
| + | * # echo `true | trap` <--- in subshell - output (but traps are reset!) |
| + | * trap -- 'echo Ho' SIGWINCH |
| + | * # echo `(trap)` <--- in subshell in subshell - output |
| + | * trap -- 'echo Ho' SIGWINCH |
| + | * # echo `true | (trap)` <--- in subshell in subshell in subshell - output! |
| + | * trap -- 'echo Ho' SIGWINCH |
| + | * |
| + | * The rules when to forget and when to not forget traps |
| + | * get really complex and nonsensical. |
| + | * |
| + | * Our solution: ONLY bare $(trap) or `trap` is special. |
| + | */ |
| + | } else { |
| + | clear_traps(); |
| + | } |
| #if JOBS | |
| /* do job control only in root shell */ | |
| doing_jobctl = 0; | |
| @@ -4597,8 +4642,14 @@ forkchild(struct job *jp, union node *n, int mode) | |
| setsignal(SIGQUIT); | |
| } | |
| #if JOBS | |
| - | if (n && n->type == NCMD && strcmp(n->ncmd.args->narg.text, "jobs") == 0) { |
| + | if (n && n->type == NCMD |
| + | && strcmp(n->ncmd.args->narg.text, "jobs") == 0 |
| + | ) { |
| TRACE(("Job hack\n")); | |
| + | /* "jobs": we do not want to clear job list for it, |
| + | * instead we remove only _its_ own_ job from job list. |
| + | * This makes "jobs .... | cat" more useful. |
| + | */ |
| freejob(curjob); | |
| return; | |
| } | |
| @@ -12208,7 +12259,7 @@ trapcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM) | |
| if (!*ap) { | |
| for (signo = 0; signo < NSIG; signo++) { | |
| if (trap[signo] != NULL) { | |
| - | out1fmt("trap -- %s %s\n", |
| + | out1fmt("trap -- %s SIG%s\n", |
| single_quote(trap[signo]), | |
| get_signame(signo)); | |
| } | |
shell/ash_test/ash-signals/savetrap.right+3 -0
| @@ -0,0 +1,3 @@ | |
| + | trap -- 'echo WINCH!' SIGWINCH |
| + | trap -- 'echo WINCH!' SIGWINCH |
| + | Done |
shell/ash_test/ash-signals/savetrap.tests+6 -0
| @@ -0,0 +1,6 @@ | |
| + | trap 'echo WINCH!' SIGWINCH |
| + | v=` trap ` |
| + | echo $v |
| + | v=`trap` |
| + | echo $v |
| + | echo Done |
shell/ash_test/ash-signals/signal1.right+5 -5
| @@ -1,20 +1,20 @@ | |
| got signal | |
| - | trap -- 'echo got signal' USR1 |
| + | trap -- 'echo got signal' SIGUSR1 |
| sent 1 signal | |
| got signal | |
| wait interrupted | |
| - | trap -- 'echo got signal' USR1 |
| + | trap -- 'echo got signal' SIGUSR1 |
| sent 2 signal | |
| got signal | |
| wait interrupted | |
| - | trap -- 'echo got signal' USR1 |
| + | trap -- 'echo got signal' SIGUSR1 |
| sent 3 signal | |
| got signal | |
| wait interrupted | |
| - | trap -- 'echo got signal' USR1 |
| + | trap -- 'echo got signal' SIGUSR1 |
| sent 4 signal | |
| got signal | |
| wait interrupted | |
| - | trap -- 'echo got signal' USR1 |
| + | trap -- 'echo got signal' SIGUSR1 |
| sent 5 signal | |
| sleep completed | |