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authorDenys Vlasenko <vda.linux@googlemail.com>2011-05-12 11:12:47 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2011-05-12 11:12:47 (GMT)
commit75e77deab11dc976d55197fcd6021030ed323e07 (patch)
tree866bab5b43960e74bae3e7ab423a54801bc745d3
parentebc1ee2e2a243a0ff3de6d2b70406ba75b771fa0 (diff)
downloadbusybox-75e77deab11dc976d55197fcd6021030ed323e07.tar.gz
busybox-75e77deab11dc976d55197fcd6021030ed323e07.tar.bz2
hush: fixes and small shrink for HUSH_JOB!=y
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--shell/hush.c27
1 files changed, 17 insertions, 10 deletions
diff --git a/shell/hush.c b/shell/hush.c
index bb95d63..132b974 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -805,9 +805,9 @@ struct globals {
unsigned special_sig_mask;
#if ENABLE_HUSH_JOB
unsigned fatal_sig_mask;
-#define G_fatal_sig_mask G.fatal_sig_mask
+# define G_fatal_sig_mask G.fatal_sig_mask
#else
-#define G_fatal_sig_mask 0
+# define G_fatal_sig_mask 0
#endif
char **traps; /* char *traps[NSIG] */
sigset_t pending_set;
@@ -1414,6 +1414,9 @@ static void restore_G_args(save_arg_t *sv, char **argv)
* Standard says "When a subshell is entered, traps that are not being ignored
* are set to the default actions". bash interprets it so that traps which
* are set to '' (ignore) are NOT reset to defaults. We do the same.
+ *
+ * TODO: don't use signal() to install sighandlers: need to mask ALL signals
+ * while handler runs. I saw signal nesting in one strace, race window isn't small.
*/
enum {
SPECIAL_INTERACTIVE_SIGS = 0
@@ -1486,12 +1489,13 @@ static sighandler_t pick_sighandler(unsigned sig)
unsigned sigmask = (1 << sig);
#if ENABLE_HUSH_JOB
- /* sig is fatal? */
+ /* is sig fatal? */
if (G_fatal_sig_mask & sigmask)
handler = sigexit;
+ else
#endif
/* sig has special handling? */
- else if (G.special_sig_mask & sigmask) {
+ if (G.special_sig_mask & sigmask) {
handler = record_pending_signo;
/* TTIN/TTOU/TSTP can't be set to record_pending_signo
* in order to ignore them: they will be raised
@@ -5604,9 +5608,6 @@ static void re_execute_shell(char ***to_free, const char *s,
* _inside_ group (just before echo 1), it works.
*
* I conclude it means we don't need to pass active traps here.
- * Even if we would use signal handlers instead of signal masking
- * in order to implement trap handling,
- * exec syscall below resets signals to SIG_DFL for us.
*/
*pp++ = (char *) "-c";
*pp++ = (char *) s;
@@ -5623,7 +5624,9 @@ static void re_execute_shell(char ***to_free, const char *s,
do_exec:
debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
- switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
+ /* Don't propagate SIG_IGN to the child */
+ if (SPECIAL_JOBSTOP_SIGS != 0)
+ switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
execve(bb_busybox_exec_path, argv, pp);
/* Fallback. Useful for init=/bin/hush usage etc */
if (argv[0][0] == '/')
@@ -6277,7 +6280,9 @@ static void execvp_or_die(char **argv) NORETURN;
static void execvp_or_die(char **argv)
{
debug_printf_exec("execing '%s'\n", argv[0]);
- switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
+ /* Don't propagate SIG_IGN to the child */
+ if (SPECIAL_JOBSTOP_SIGS != 0)
+ switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
execvp(argv[0], argv);
bb_perror_msg("can't execute '%s'", argv[0]);
_exit(127); /* bash compat */
@@ -6409,7 +6414,9 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
# endif
/* Re-exec ourselves */
debug_printf_exec("re-execing applet '%s'\n", argv[0]);
- switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
+ /* Don't propagate SIG_IGN to the child */
+ if (SPECIAL_JOBSTOP_SIGS != 0)
+ switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
execv(bb_busybox_exec_path, argv);
/* If they called chroot or otherwise made the binary no longer
* executable, fall through */