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Re: "echo | ps -j $(:) | cat | cat | cat" runs components in different process groups
>} The ampersand is therefore parsed rather late to be able to see you
>need } this structure. So it probably needs some other trick --- a
>different } list marker that causes a special null command akin to
>time to do the } fork, for example, as it's easy to update word code
>tokens when the } structure doesn't change.
>
> So what we'd need to do (?) is insert a no-op token in the wordcode at
> the "front" of the parse, and update it to be an "in background" token
> in the event the parse ends at "&" (or "&!" etc.) ...
>
>} The logic would then be within the exec code
>
> ... which would ignore the no-op or invoke an additional execcmd_bg()
> to exec the pipeline after the fork.
This strikes me as baroque enough we might just as well look at fixing
it properly. This is likely to have obscure side effects of one sort or
another, too, but with them being localised to execcmd_exec() I hope
they'd be a bit more obvious than changing the execution structure...
This is a first go that doesn't appear to be completely broken. Lots of
rearranging and reindenting, very little novel code. I'm not sure how
much git users feel like being guinea pigs.
pws
diff --git a/Src/exec.c b/Src/exec.c
index f6c768f..5ea3e0b 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -2707,6 +2707,77 @@ static void execcmd_getargs(LinkList preargs, LinkList args, int expand)
}
}
+/**/
+static int execcmd_fork(Estate state, int how, int type, Wordcode varspc,
+ LinkList *filelistp, char *text, int oautocont)
+{
+ pid_t pid;
+ int synch[2], flags;
+ char dummy;
+ struct timeval bgtime;
+
+ child_block();
+
+ if (pipe(synch) < 0) {
+ zerr("pipe failed: %e", errno);
+ return -1;
+ } else if ((pid = zfork(&bgtime)) == -1) {
+ close(synch[0]);
+ close(synch[1]);
+ lastval = 1;
+ errflag |= ERRFLAG_ERROR;
+ return -1;
+ }
+ if (pid) {
+ close(synch[1]);
+ read_loop(synch[0], &dummy, 1);
+ close(synch[0]);
+ if (how & Z_ASYNC) {
+ lastpid = (zlong) pid;
+ } else if (!jobtab[thisjob].stty_in_env && varspc) {
+ /* search for STTY=... */
+ Wordcode p = varspc;
+ wordcode ac;
+
+ while (wc_code(ac = *p) == WC_ASSIGN) {
+ if (!strcmp(ecrawstr(state->prog, p + 1, NULL), "STTY")) {
+ jobtab[thisjob].stty_in_env = 1;
+ break;
+ }
+ p += (WC_ASSIGN_TYPE(ac) == WC_ASSIGN_SCALAR ?
+ 3 : WC_ASSIGN_NUM(ac) + 2);
+ }
+ }
+ addproc(pid, text, 0, &bgtime);
+ if (oautocont >= 0)
+ opts[AUTOCONTINUE] = oautocont;
+ pipecleanfilelist(jobtab[thisjob].filelist, 1);
+ return pid;
+ }
+
+ /* pid == 0 */
+ close(synch[0]);
+ flags = ((how & Z_ASYNC) ? ESUB_ASYNC : 0) | ESUB_PGRP;
+ if ((type != WC_SUBSH) && !(how & Z_ASYNC))
+ flags |= ESUB_KEEPTRAP;
+ if (type == WC_SUBSH && !(how & Z_ASYNC))
+ flags |= ESUB_JOB_CONTROL;
+ *filelistp = jobtab[thisjob].filelist;
+ entersubsh(flags);
+ close(synch[1]);
+
+ if (sigtrapped[SIGINT] & ZSIG_IGNORED)
+ holdintr();
+#ifdef HAVE_NICE
+ /* Check if we should run background jobs at a lower priority. */
+ if ((how & Z_ASYNC) && isset(BGNICE))
+ if (nice(5) < 0)
+ zwarn("nice(5) failed: %e", errno);
+#endif /* HAVE_NICE */
+
+ return 0;
+}
+
/*
* Execute a command at the lowest level of the hierarchy.
*/
@@ -3074,6 +3145,21 @@ execcmd_exec(Estate state, Execcmd_params eparams,
esprefork = (magic_assign ||
(isset(MAGICEQUALSUBST) && type != WC_TYPESET)) ?
PREFORK_TYPESET : 0;
+ if (how & Z_ASYNC) {
+ text = getjobtext(state->prog, eparams->beg);
+ switch (execcmd_fork(state, how, type, varspc, &filelist,
+ text, oautocont)) {
+ case -1:
+ goto fatal;
+ case 0:
+ break;
+ default:
+ return;
+ }
+ forked = 1;
+ } else
+ text = NULL;
+
if (args) {
if (eparams->htok)
prefork(args, esprefork, NULL);
@@ -3226,11 +3312,9 @@ execcmd_exec(Estate state, Execcmd_params eparams,
}
/* Get the text associated with this command. */
- if ((how & Z_ASYNC) ||
+ if (!text &&
(!sfcontext && (jobbing || (how & Z_TIMED))))
text = getjobtext(state->prog, eparams->beg);
- else
- text = NULL;
/*
* Set up special parameter $_
@@ -3397,99 +3481,45 @@ execcmd_exec(Estate state, Execcmd_params eparams,
* current shell. *
**************************************************************************/
- if ((how & Z_ASYNC) ||
- (!do_exec &&
- (((is_builtin || is_shfunc) && output) ||
- (!is_cursh && (last1 != 1 || nsigtrapped || havefiles() ||
- fdtable_flocks))))) {
-
- pid_t pid;
- int synch[2], flags;
- char dummy;
- struct timeval bgtime;
-
- child_block();
-
- if (pipe(synch) < 0) {
- zerr("pipe failed: %e", errno);
- goto fatal;
- } else if ((pid = zfork(&bgtime)) == -1) {
- close(synch[0]);
- close(synch[1]);
- lastval = 1;
- errflag |= ERRFLAG_ERROR;
- goto fatal;
- }
- if (pid) {
-
- close(synch[1]);
- read_loop(synch[0], &dummy, 1);
- close(synch[0]);
- if (how & Z_ASYNC) {
- lastpid = (zlong) pid;
- } else if (!jobtab[thisjob].stty_in_env && varspc) {
- /* search for STTY=... */
- Wordcode p = varspc;
- wordcode ac;
-
- while (wc_code(ac = *p) == WC_ASSIGN) {
- if (!strcmp(ecrawstr(state->prog, p + 1, NULL), "STTY")) {
- jobtab[thisjob].stty_in_env = 1;
- break;
- }
- p += (WC_ASSIGN_TYPE(ac) == WC_ASSIGN_SCALAR ?
- 3 : WC_ASSIGN_NUM(ac) + 2);
- }
+ if (!forked) {
+ if (!do_exec &&
+ (((is_builtin || is_shfunc) && output) ||
+ (!is_cursh && (last1 != 1 || nsigtrapped || havefiles() ||
+ fdtable_flocks)))) {
+ switch (execcmd_fork(state, how, type, varspc, &filelist,
+ text, oautocont)) {
+ case -1:
+ goto fatal;
+ case 0:
+ break;
+ default:
+ return;
}
- addproc(pid, text, 0, &bgtime);
- if (oautocont >= 0)
- opts[AUTOCONTINUE] = oautocont;
- pipecleanfilelist(jobtab[thisjob].filelist, 1);
- return;
- }
- /* pid == 0 */
- close(synch[0]);
- flags = ((how & Z_ASYNC) ? ESUB_ASYNC : 0) | ESUB_PGRP;
- if ((type != WC_SUBSH) && !(how & Z_ASYNC))
- flags |= ESUB_KEEPTRAP;
- if (type == WC_SUBSH && !(how & Z_ASYNC))
- flags |= ESUB_JOB_CONTROL;
- filelist = jobtab[thisjob].filelist;
- entersubsh(flags);
- close(synch[1]);
- forked = 1;
- if (sigtrapped[SIGINT] & ZSIG_IGNORED)
- holdintr();
-#ifdef HAVE_NICE
- /* Check if we should run background jobs at a lower priority. */
- if ((how & Z_ASYNC) && isset(BGNICE))
- if (nice(5) < 0)
- zwarn("nice(5) failed: %e", errno);
-#endif /* HAVE_NICE */
-
- } else if (is_cursh) {
- /* This is a current shell procedure that didn't need to fork. *
- * This includes current shell procedures that are being exec'ed, *
- * as well as null execs. */
- jobtab[thisjob].stat |= STAT_CURSH;
- if (!jobtab[thisjob].procs)
- jobtab[thisjob].stat |= STAT_NOPRINT;
- if (is_builtin)
- jobtab[thisjob].stat |= STAT_BUILTIN;
- } else {
- /* This is an exec (real or fake) for an external command. *
- * Note that any form of exec means that the subshell is fake *
- * (but we may be in a subshell already). */
- is_exec = 1;
- /*
- * If we are in a subshell environment anyway, say we're forked,
- * even if we're actually not forked because we know the
- * subshell is exiting. This ensures SHLVL reflects the current
- * shell, and also optimises out any save/restore we'd need to
- * do if we were returning to the main shell.
- */
- if (type == WC_SUBSH)
forked = 1;
+ } else if (is_cursh) {
+ /* This is a current shell procedure that didn't need to fork. *
+ * This includes current shell procedures that are being exec'ed, *
+ * as well as null execs. */
+ jobtab[thisjob].stat |= STAT_CURSH;
+ if (!jobtab[thisjob].procs)
+ jobtab[thisjob].stat |= STAT_NOPRINT;
+ if (is_builtin)
+ jobtab[thisjob].stat |= STAT_BUILTIN;
+ } else {
+ /* This is an exec (real or fake) for an external command. *
+ * Note that any form of exec means that the subshell is fake *
+ * (but we may be in a subshell already). */
+ is_exec = 1;
+ /*
+ * If we are in a subshell environment anyway, say we're forked,
+ * even if we're actually not forked because we know the
+ * subshell is exiting. This ensures SHLVL reflects the current
+ * shell, and also optimises out any save/restore we'd need to
+ * do if we were returning to the main shell.
+ */
+ if (type == WC_SUBSH)
+ forked = 1;
+ }
}
if ((esglob = !(cflags & BINF_NOGLOB)) && args && eparams->htok) {
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