hush: use SA_RESTARTed signal handlers across read.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/hush.c b/shell/hush.c
index 71972f7..509bd41 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -792,8 +792,13 @@
unsigned handled_SIGCHLD;
smallint we_have_children;
#endif
- /* which signals have non-DFL handler (even with no traps set)? */
- unsigned non_DFL_mask;
+ /* Which signals have non-DFL handler (even with no traps set)?
+ * Set at the start to:
+ * (SIGQUIT + maybe SPECIAL_INTERACTIVE_SIGS + maybe SPECIAL_JOB_SIGS)
+ * SPECIAL_INTERACTIVE_SIGS are cleared after fork.
+ * Other than these two times, never modified.
+ */
+ unsigned special_sig_mask;
char **traps; /* char *traps[NSIG] */
/* Signal mask on the entry to the (top-level) shell. Never modified. */
sigset_t inherited_set;
@@ -1341,11 +1346,11 @@
* After each pipe execution, we extract any pending signals via sigtimedwait()
* and act on them.
*
- * unsigned non_DFL_mask: a mask of such "special" signals
+ * unsigned special_sig_mask: a mask of such "special" signals
* sigset_t blocked_set: current blocked signal set
*
* "trap - SIGxxx":
- * clear bit in blocked_set unless it is also in non_DFL_mask
+ * clear bit in blocked_set unless it is also in special_sig_mask
* "trap 'cmd' SIGxxx":
* set bit in blocked_set (even if 'cmd' is '')
* after [v]fork, if we plan to be a shell:
@@ -5376,7 +5381,7 @@
* Testcase: (while :; do :; done) + ^Z should background.
* Same goes for SIGTERM, SIGHUP, SIGINT.
*/
- if (!G.traps && !(G.non_DFL_mask & SPECIAL_INTERACTIVE_SIGS))
+ if (!G.traps && !(G.special_sig_mask & SPECIAL_INTERACTIVE_SIGS))
return; /* already no traps and no SPECIAL_INTERACTIVE_SIGS */
/* Switching off SPECIAL_INTERACTIVE_SIGS.
@@ -5394,10 +5399,10 @@
}
}
/* Our homegrown sig mask is saner to work with :) */
- G.non_DFL_mask &= ~SPECIAL_INTERACTIVE_SIGS;
+ G.special_sig_mask &= ~SPECIAL_INTERACTIVE_SIGS;
/* Resetting all traps to default except empty ones */
- mask = G.non_DFL_mask;
+ mask = G.special_sig_mask;
if (G.traps) for (sig = 0; sig < NSIG; sig++, mask >>= 1) {
if (!G.traps[sig] || !G.traps[sig][0])
continue;
@@ -7440,9 +7445,6 @@
/* POSIX allows shell to re-enable SIGCHLD
* even if it was SIG_IGN on entry */
-#if ENABLE_HUSH_FAST
- G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
-#endif
if (!G.inherited_set_is_saved) {
#if ENABLE_HUSH_FAST
signal(SIGCHLD, SIGCHLD_handler);
@@ -7460,7 +7462,7 @@
if (G_saved_tty_pgrp) /* we have ctty, job control sigs work */
mask |= SPECIAL_JOB_SIGS;
}
- G.non_DFL_mask = mask;
+ G.special_sig_mask = mask;
/* Block them. And unblock SIGCHLD */
sig = 0;
@@ -7504,10 +7506,10 @@
/*+ (1 << SIGINT )*/
;
- /* non_DFL_mask'ed signals are, well, masked,
+ /* special_sig_mask'ed signals are, well, masked,
* no need to set handler for them.
*/
- fatal_sigs &= ~G.non_DFL_mask;
+ fatal_sigs &= ~G.special_sig_mask;
/* For each sig in fatal_sigs... */
sig = 0;
@@ -7571,8 +7573,11 @@
struct variable *shell_ver;
INIT_G();
- if (EXIT_SUCCESS) /* if EXIT_SUCCESS == 0, it is already done */
+ if (EXIT_SUCCESS != 0) /* if EXIT_SUCCESS == 0, it is already done */
G.last_exitcode = EXIT_SUCCESS;
+#if ENABLE_HUSH_FAST
+ G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
+#endif
#if !BB_MMU
G.argv0_for_re_execing = argv[0];
#endif
@@ -8303,7 +8308,7 @@
/* There was a trap handler, we are removing it
* (if sig has non-DFL handling,
* we don't need to do anything) */
- if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
+ if (sig < sizeof(G.special_sig_mask)*8 && (G.special_sig_mask & (1 << sig)))
continue;
sigdelset(&G.blocked_set, sig);
}
@@ -8565,7 +8570,7 @@
memset(&sa, 0, sizeof(sa));
sigfillset(&sa.sa_mask);
- /*sa.sa_flags = 0;*/
+ sa.sa_flags = SA_RESTART;
sa.sa_handler = record_signal;
sig = 0;
diff --git a/shell/shell_common.c b/shell/shell_common.c
index a5c455c..bbc22ed 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -159,32 +159,40 @@
bufpos = 0;
do {
char c;
+ struct pollfd pfd[1];
+ int timeout;
- errno = 0;
+ if ((bufpos & 0xff) == 0)
+ buffer = xrealloc(buffer, bufpos + 0x100);
+ timeout = -1;
if (end_ms) {
- int timeout;
- struct pollfd pfd[1];
-
- pfd[0].fd = fd;
- pfd[0].events = POLLIN;
timeout = end_ms - (unsigned)monotonic_ms();
- if (timeout <= 0 /* already late? */
- || poll(pfd, 1, timeout) != 1 /* no? wait... */
- ) { /* timed out! */
- err = errno;
+ if (timeout <= 0) { /* already late? */
retval = (const char *)(uintptr_t)1;
goto ret;
}
}
- if ((bufpos & 0xff) == 0)
- buffer = xrealloc(buffer, bufpos + 0x100);
- if (nonblock_immune_read(fd, &buffer[bufpos], 1, /*loop_on_EINTR:*/ 0) != 1) {
+ /* We must poll even if timeout is -1:
+ * we want to be interrupted if signal arrives,
+ * regardless of SA_RESTART-ness of that signal!
+ */
+ errno = 0;
+ pfd[0].fd = fd;
+ pfd[0].events = POLLIN;
+ if (poll(pfd, 1, timeout) != 1) {
+ /* timed out, or EINTR */
+ err = errno;
+ retval = (const char *)(uintptr_t)1;
+ goto ret;
+ }
+ if (read(fd, &buffer[bufpos], 1) != 1) {
err = errno;
retval = (const char *)(uintptr_t)1;
break;
}
+
c = buffer[bufpos];
if (c == '\0')
continue;