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hush: fix more backgrounding bugs. Plenty of them remains still.

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This commit is contained in:
Denis Vlasenko 2007-04-21 13:42:52 +00:00
parent 2f1bb36a55
commit 52881e9f23
2 changed files with 29 additions and 11 deletions
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8
shell/README
View File

@ -1,6 +1,12 @@
Various bits of what is known about busybox shells, in no particular order.
2007-04-22
2007-04-21
hush: fixed non-backgrounding of "sleep 1 &" and totally broken
"sleep 1 | sleep 2 &". Noticed a bug where successive jobs
get numbers 1,2,3 even when job #1 has exited before job# 2 is started.
(bash reuses #1 in this case)
2007-04-21
hush: "sleep 1 | exit 3; echo $?" prints 0 because $? is substituted
_before_ pipe gets executed!! run_list_real() already has "pipe;echo"
parsed and handed to it for execution, so it sees "pipe"; "echo 0".

32
shell/hush.c
View File

@ -384,6 +384,7 @@ static int parse_string_outer(const char *s, int flag);
static int parse_file_outer(FILE *f);
/* job management: */
static int checkjobs(struct pipe* fg_pipe);
static int checkjobs_and_fg_shell(struct pipe* fg_pipe);
static void insert_bg_job(struct pipe *pi);
static void remove_bg_job(struct pipe *pi);
/* local variable support */
@ -648,6 +649,8 @@ static int builtin_fg_bg(struct child_prog *child)
bb_error_msg("%s: %d: no such job", child->argv[0], jobnum);
return EXIT_FAILURE;
found:
// TODO: bash prints a string representation
// of job being foregrounded (like "sleep 1 | cat")
if (*child->argv[0] == 'f') {
/* Put the job into the foreground. */
tcsetpgrp(interactive_fd, pi->pgrp);
@ -658,6 +661,7 @@ static int builtin_fg_bg(struct child_prog *child)
pi->progs[i].is_stopped = 0;
i = kill(- pi->pgrp, SIGCONT);
pi->stopped_progs = 0;
if (i < 0) {
if (errno == ESRCH) {
remove_bg_job(pi);
@ -666,7 +670,8 @@ static int builtin_fg_bg(struct child_prog *child)
}
}
pi->stopped_progs = 0;
if (*child->argv[0] == 'f')
return checkjobs_and_fg_shell(pi);
return EXIT_SUCCESS;
}
@ -1350,6 +1355,18 @@ static int checkjobs(struct pipe* fg_pipe)
return rcode;
}
static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
{
pid_t p;
int rcode = checkjobs(fg_pipe);
/* Job finished, move the shell to the foreground */
p = getpgid(0);
debug_printf("fg'ing ourself: getpgid(0)=%d\n", (int)p);
if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY)
bb_perror_msg("tcsetpgrp-4a");
return rcode;
}
/* run_pipe_real() starts all the jobs, but doesn't wait for anything
* to finish. See checkjobs().
*
@ -1377,6 +1394,7 @@ static int run_pipe_real(struct pipe *pi)
/* it is not always needed, but we aim to smaller code */
int squirrel[] = { -1, -1, -1 };
int rcode;
const int single_fg = (pi->num_progs == 1 && pi->followup != PIPE_BG);
nextin = 0;
pi->pgrp = -1;
@ -1386,7 +1404,7 @@ static int run_pipe_real(struct pipe *pi)
* pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
*/
child = &(pi->progs[0]);
if (pi->num_progs == 1 && child->group && child->subshell == 0) {
if (single_fg && child->group && child->subshell == 0) {
debug_printf("non-subshell grouping\n");
setup_redirects(child, squirrel);
/* XXX could we merge code with following builtin case,
@ -1396,7 +1414,7 @@ static int run_pipe_real(struct pipe *pi)
return rcode;
}
if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
if (single_fg && pi->progs[0].argv != NULL) {
for (i = 0; is_assignment(child->argv[i]); i++)
continue;
if (i != 0 && child->argv[i] == NULL) {
@ -1675,13 +1693,7 @@ static int run_list_real(struct pipe *pi)
rcode = EXIT_SUCCESS;
} else {
if (interactive_fd) {
pid_t p;
rcode = checkjobs(pi);
/* move the shell to the foreground */
p = getpgid(0);
if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY)
bb_perror_msg("tcsetpgrp-4");
debug_printf("getpgid(0)=%d\n", (int)p);
rcode = checkjobs_and_fg_shell(pi);
} else {
rcode = checkjobs(pi);
}