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3ac0e0055

Denis Vlasenko
Denis Vlasenko
2007-04-28
FAILED Duration: 16s

Subject

hush: better signal handling across ctrl-z

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No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

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Build Log

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Commit Diff GitHub →

shell/hush.c +127 -87
shell/hush.c+127 -87
@@ -193,7 +193,7 @@ struct pipe {
int jobid; /* job number */
int num_progs; /* total number of programs in job */
int running_progs; /* number of programs running (not exited) */
- char *text; /* name of job */
+ char *cmdtext; /* name of job */
char *cmdbuf; /* buffer various argv's point into */
pid_t pgrp; /* process group ID for the job */
struct child_prog *progs; /* array of commands in pipe */
@@ -441,6 +441,42 @@ static void signal_SA_RESTART(int sig, void (*handler)(int))
sigaction(sig, &sa, NULL);
}
+/* Signals are grouped, we handle them in batches */
+static void set_fatal_sighandler(void (*handler)(int))
+{
+ signal(SIGILL , handler);
+ signal(SIGTRAP, handler);
+ signal(SIGABRT, handler);
+ signal(SIGFPE , handler);
+ signal(SIGBUS , handler);
+ signal(SIGSEGV, handler);
+ /* bash 3.2 seems to handle these just like 'fatal' ones */
+ signal(SIGHUP , handler);
+ signal(SIGPIPE, handler);
+ signal(SIGALRM, handler);
+}
+static void set_jobctrl_sighandler(void (*handler)(int))
+{
+ signal(SIGTSTP, handler);
+ signal(SIGTTIN, handler);
+ signal(SIGTTOU, handler);
+}
+static void set_misc_sighandler(void (*handler)(int))
+{
+ signal(SIGINT , handler);
+ signal(SIGQUIT, handler);
+ signal(SIGTERM, handler);
+}
+/* SIGCHLD is special and handled separately */
+
+static void set_every_sighandler(void (*handler)(int))
+{
+ set_fatal_sighandler(handler);
+ set_jobctrl_sighandler(handler);
+ set_misc_sighandler(handler);
+ signal(SIGCHLD, handler);
+}
+
struct nofork_save_area nofork_save;
static sigjmp_buf nofork_jb;
static struct pipe *nofork_pipe;
@@ -460,7 +496,7 @@ static void handler_ctrl_z(int sig)
if (!pid) { /* child */
debug_jobs_printf("setting pgrp for child\n");
setpgrp();
- signal(SIGTSTP, SIG_DFL); /* make child do default action (stop) */
+ set_every_sighandler(SIG_DFL);
raise(SIGTSTP); /* resend TSTP so that child will be stopped */
debug_jobs_printf("returning to child\n");
/* return to nofork, it will eventually exit now,
@@ -516,35 +552,6 @@ static void hush_exit(int exitcode)
sigexit(- (exitcode & 0xff));
}
-/* Signals are grouped, we handle them in batches */
-static void set_fatal_sighandler(void (*handler)(int))
-{
- signal(SIGILL , handler);
- signal(SIGTRAP, handler);
- signal(SIGABRT, handler);
- signal(SIGFPE , handler);
- signal(SIGBUS , handler);
- signal(SIGSEGV, handler);
- /* bash 3.2 seems to handle these just like 'fatal' ones,
- * but _without_ printing signal name. TODO: mimic this too? */
- signal(SIGHUP , handler);
- signal(SIGPIPE, handler);
- signal(SIGALRM, handler);
-}
-static void set_jobctrl_sighandler(void (*handler)(int))
-{
- signal(SIGTSTP, handler);
- signal(SIGTTIN, handler);
- signal(SIGTTOU, handler);
-}
-static void set_misc_sighandler(void (*handler)(int))
-{
- signal(SIGINT , handler);
- signal(SIGQUIT, handler);
- signal(SIGTERM, handler);
-}
-/* SIGCHLD is special and handled separately */
-
static const char *set_cwd(void)
{
if (cwd == bb_msg_unknown)
@@ -719,6 +726,7 @@ static int builtin_fg_bg(char **argv)
if (i < 0) {
if (errno == ESRCH) {
delete_finished_bg_job(pi);
+ return EXIT_SUCCESS;
} else {
bb_perror_msg("kill (SIGCONT)");
}
@@ -759,7 +767,7 @@ static int builtin_jobs(char **argv ATTRIBUTE_UNUSED)
else
status_string = "Running";
- printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
+ printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
}
return EXIT_SUCCESS;
}
@@ -1266,6 +1274,35 @@ static void pseudo_exec(struct child_prog *child)
_exit(EXIT_SUCCESS);
}
+static const char *get_cmdtext(struct pipe *pi)
+{
+ char **argv;
+ char *p;
+ int len;
+
+ /* This is subtle. ->cmdtext is created only on first backgrounding.
+ * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
+ * On subsequent bg argv can be trashed, but we won't use it */
+ if (pi->cmdtext)
+ return pi->cmdtext;
+ argv = pi->progs[0].argv;
+ if (!argv || !argv[0])
+ return (pi->cmdtext = xzalloc(1));
+
+ len = 0;
+ do len += strlen(*argv) + 1; while (*++argv);
+ pi->cmdtext = p = xmalloc(len);
+ argv = pi->progs[0].argv;
+ do {
+ len = strlen(*argv);
+ memcpy(p, *argv, len);
+ p += len;
+ *p++ = ' ';
+ } while (*++argv);
+ p[-1] = '\0';
+ return pi->cmdtext;
+}
+
static void insert_bg_job(struct pipe *pi)
{
struct pipe *thejob;
@@ -1288,27 +1325,17 @@ static void insert_bg_job(struct pipe *pi)
/* physically copy the struct job */
memcpy(thejob, pi, sizeof(struct pipe));
-// (pi->num_progs+1) is one-too-many I think?
- thejob->progs = xmalloc(sizeof(pi->progs[0]) * (pi->num_progs+1));
- memcpy(thejob->progs, pi->progs, sizeof(pi->progs[0]) * (pi->num_progs+1));
+ thejob->progs = xmalloc(sizeof(pi->progs[0]) * pi->num_progs);
+ memcpy(thejob->progs, pi->progs, sizeof(pi->progs[0]) * pi->num_progs);
thejob->next = NULL;
/*seems to be wrong:*/
/*thejob->running_progs = thejob->num_progs;*/
/*thejob->stopped_progs = 0;*/
- thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
- //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
- {
- // FIXME: overflow check? and also trim the size, BUFSIZ can be 4K!
- char *bar = thejob->text;
- char **foo = pi->progs[0].argv;
- if (foo)
- while (*foo)
- bar += sprintf(bar, "%s ", *foo++);
- }
+ thejob->cmdtext = xstrdup(get_cmdtext(pi));
/* we don't wait for background thejobs to return -- append it
to the list of backgrounded thejobs and leave it alone */
- printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
+ printf("[%d] %d %s\n", thejob->jobid, thejob->progs[0].pid, thejob->cmdtext);
last_bg_pid = thejob->progs[0].pid;
last_jobid = thejob->jobid;
}
@@ -1433,7 +1460,7 @@ static int checkjobs(struct pipe* fg_pipe)
pi->running_progs--;
if (!pi->running_progs) {
printf(JOB_STATUS_FORMAT, pi->jobid,
- "Done", pi->text);
+ "Done", pi->cmdtext);
delete_finished_bg_job(pi);
}
} else {
@@ -1466,6 +1493,32 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
return rcode;
}
+/* run_pipe_real's helper */
+static int run_single_fg_nofork(struct pipe *pi, const struct bb_applet *a,
+ char **argv)
+{
+ int rcode;
+ /* TSTP handler will store pid etc in pi */
+ nofork_pipe = pi;
+ save_nofork_data(&nofork_save);
+ if (sigsetjmp(nofork_jb, 1) == 0) {
+ signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
+ rcode = run_nofork_applet_prime(&nofork_save, a, argv);
+ if (--nofork_save.saved != 0) {
+ /* Ctrl-Z forked, we are child */
+ exit(rcode);
+ }
+ return rcode;
+ }
+ /* Ctrl-Z forked, we are parent.
+ * Sighandler has longjmped us here */
+ signal(SIGTSTP, SIG_IGN);
+ debug_jobs_printf("Exiting nofork early\n");
+ restore_nofork_data(&nofork_save);
+ insert_bg_job(pi);
+ return 0;
+}
+
/* run_pipe_real() starts all the jobs, but doesn't wait for anything
* to finish. See checkjobs().
*
@@ -1575,6 +1628,7 @@ static int run_pipe_real(struct pipe *pi)
* This is perfect for work that comes after exec().
* Is it really safe for inline use? Experimentally,
* things seem to work with glibc. */
+// TODO: fflush(NULL)?
setup_redirects(child, squirrel);
rcode = x->function(argv + i);
restore_redirects(squirrel);
@@ -1586,32 +1640,16 @@ static int run_pipe_real(struct pipe *pi)
const struct bb_applet *a = find_applet_by_name(argv[i]);
if (a && a->nofork) {
setup_redirects(child, squirrel);
- /* TSTP handler will store pid etc in pi */
- nofork_pipe = pi;
- save_nofork_data(&nofork_save);
- if (sigsetjmp(nofork_jb, 1) == 0) {
- signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
- rcode = run_nofork_applet_prime(&nofork_save, a, argv + i);
- if (--nofork_save.saved != 0)
- /* Ctrl-Z! forked, we are child */
- exit(rcode);
- restore_redirects(squirrel);
- return rcode;
- } else {
- /* Ctrl-Z, forked, we are parent.
- * Sighandler has longjmped us here */
- signal(SIGTSTP, SIG_IGN);
- debug_jobs_printf("Exiting nofork early\n");
- restore_nofork_data(&nofork_save);
- restore_redirects(squirrel);
- insert_bg_job(pi);
- return 0;
- }
+ rcode = run_single_fg_nofork(pi, a, argv + i);
+ restore_redirects(squirrel);
+ return rcode;
}
}
#endif
}
+ /* Going to fork a child per each pipe member */
+
/* Disable job control signals for shell (parent) and
* for initial child code after fork */
set_jobctrl_sighandler(SIG_IGN);
@@ -1639,6 +1677,8 @@ static int run_pipe_real(struct pipe *pi)
/* Every child adds itself to new process group
* with pgid == pid of first child in pipe */
if (interactive_fd) {
+ /* Don't do pgrp restore anymore on fatal signals */
+ set_fatal_sighandler(SIG_DFL);
if (pi->pgrp < 0) /* true for 1st process only */
pi->pgrp = getpid();
if (setpgid(0, pi->pgrp) == 0 && pi->followup != PIPE_BG) {
@@ -1646,8 +1686,6 @@ static int run_pipe_real(struct pipe *pi)
* to avoid races */
tcsetpgrp(interactive_fd, pi->pgrp);
}
- /* Don't do pgrp restore anymore on fatal signals */
- set_fatal_sighandler(SIG_DFL);
}
// in non-interactive case fatal sigs are already SIG_DFL
close_all();
@@ -1878,6 +1916,8 @@ static int free_pipe(struct pipe *pi, int indent)
}
free(pi->progs); /* children are an array, they get freed all at once */
pi->progs = NULL;
+ free(pi->cmdtext);
+ pi->cmdtext = NULL;
return ret_code;
}
@@ -2252,12 +2292,13 @@ static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
static struct pipe *new_pipe(void)
{
struct pipe *pi;
- pi = xmalloc(sizeof(struct pipe));
- pi->num_progs = 0;
- pi->progs = NULL;
- pi->next = NULL;
- pi->followup = 0; /* invalid */
- pi->r_mode = RES_NONE;
+ pi = xzalloc(sizeof(struct pipe));
+ /*pi->num_progs = 0;*/
+ /*pi->progs = NULL;*/
+ /*pi->next = NULL;*/
+ /*pi->followup = 0; invalid */
+ if (RES_NONE)
+ pi->r_mode = RES_NONE;
return pi;
}
@@ -2424,13 +2465,14 @@ static int done_command(struct p_context *ctx)
pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
prog = pi->progs + pi->num_progs;
- prog->redirects = NULL;
- prog->argv = NULL;
- prog->is_stopped = 0;
- prog->group = NULL;
- prog->glob_result.gl_pathv = NULL;
+ memset(prog, 0, sizeof(*prog));
+ /*prog->redirects = NULL;*/
+ /*prog->argv = NULL;
+ /*prog->is_stopped = 0;*/
+ /*prog->group = NULL;*/
+ /*prog->glob_result.gl_pathv = NULL;*/
prog->family = pi;
- prog->sp = 0;
+ /*prog->sp = 0;*/
ctx->child = prog;
prog->type = ctx->type;
@@ -3008,15 +3050,13 @@ static void setup_job_control(void)
set_misc_sighandler(SIG_IGN);
//huh? signal(SIGCHLD, SIG_IGN);
- /* We _must_ do cleanup on fatal signals */
+ /* We _must_ restore tty pgrp fatal signals */
set_fatal_sighandler(sigexit);
/* Put ourselves in our own process group. */
- shell_pgrp = getpid();
- setpgrp(); /* is the same as setpgid(shell_pgrp, shell_pgrp); */
-
+ setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
/* Grab control of the terminal. */
- tcsetpgrp(interactive_fd, shell_pgrp);
+ tcsetpgrp(interactive_fd, getpid());
}
int hush_main(int argc, char **argv);