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https://github.com/sheumann/hush.git
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hush: use SA_RESTARTed signal handlers across read.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
parent
12bc152b31
commit
10c0131a8a
37
shell/hush.c
37
shell/hush.c
@ -792,8 +792,13 @@ struct globals {
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unsigned handled_SIGCHLD;
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smallint we_have_children;
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#endif
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/* which signals have non-DFL handler (even with no traps set)? */
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unsigned non_DFL_mask;
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/* Which signals have non-DFL handler (even with no traps set)?
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* Set at the start to:
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* (SIGQUIT + maybe SPECIAL_INTERACTIVE_SIGS + maybe SPECIAL_JOB_SIGS)
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* SPECIAL_INTERACTIVE_SIGS are cleared after fork.
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* Other than these two times, never modified.
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*/
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unsigned special_sig_mask;
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char **traps; /* char *traps[NSIG] */
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/* Signal mask on the entry to the (top-level) shell. Never modified. */
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sigset_t inherited_set;
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@ -1341,11 +1346,11 @@ static void restore_G_args(save_arg_t *sv, char **argv)
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* After each pipe execution, we extract any pending signals via sigtimedwait()
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* and act on them.
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*
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* unsigned non_DFL_mask: a mask of such "special" signals
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* unsigned special_sig_mask: a mask of such "special" signals
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* sigset_t blocked_set: current blocked signal set
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*
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* "trap - SIGxxx":
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* clear bit in blocked_set unless it is also in non_DFL_mask
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* clear bit in blocked_set unless it is also in special_sig_mask
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* "trap 'cmd' SIGxxx":
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* set bit in blocked_set (even if 'cmd' is '')
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* after [v]fork, if we plan to be a shell:
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@ -5376,7 +5381,7 @@ static void reset_traps_to_defaults(void)
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* Testcase: (while :; do :; done) + ^Z should background.
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* Same goes for SIGTERM, SIGHUP, SIGINT.
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*/
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if (!G.traps && !(G.non_DFL_mask & SPECIAL_INTERACTIVE_SIGS))
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if (!G.traps && !(G.special_sig_mask & SPECIAL_INTERACTIVE_SIGS))
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return; /* already no traps and no SPECIAL_INTERACTIVE_SIGS */
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/* Switching off SPECIAL_INTERACTIVE_SIGS.
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@ -5394,10 +5399,10 @@ static void reset_traps_to_defaults(void)
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}
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}
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/* Our homegrown sig mask is saner to work with :) */
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G.non_DFL_mask &= ~SPECIAL_INTERACTIVE_SIGS;
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G.special_sig_mask &= ~SPECIAL_INTERACTIVE_SIGS;
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/* Resetting all traps to default except empty ones */
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mask = G.non_DFL_mask;
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mask = G.special_sig_mask;
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if (G.traps) for (sig = 0; sig < NSIG; sig++, mask >>= 1) {
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if (!G.traps[sig] || !G.traps[sig][0])
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continue;
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@ -7440,9 +7445,6 @@ static void init_sigmasks(void)
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/* POSIX allows shell to re-enable SIGCHLD
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* even if it was SIG_IGN on entry */
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#if ENABLE_HUSH_FAST
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G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
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#endif
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if (!G.inherited_set_is_saved) {
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#if ENABLE_HUSH_FAST
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signal(SIGCHLD, SIGCHLD_handler);
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@ -7460,7 +7462,7 @@ static void init_sigmasks(void)
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if (G_saved_tty_pgrp) /* we have ctty, job control sigs work */
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mask |= SPECIAL_JOB_SIGS;
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}
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G.non_DFL_mask = mask;
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G.special_sig_mask = mask;
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/* Block them. And unblock SIGCHLD */
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sig = 0;
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@ -7504,10 +7506,10 @@ static void set_fatal_handlers_to_sigexit(void)
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/*+ (1 << SIGINT )*/
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;
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/* non_DFL_mask'ed signals are, well, masked,
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/* special_sig_mask'ed signals are, well, masked,
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* no need to set handler for them.
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*/
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fatal_sigs &= ~G.non_DFL_mask;
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fatal_sigs &= ~G.special_sig_mask;
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/* For each sig in fatal_sigs... */
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sig = 0;
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@ -7571,8 +7573,11 @@ int hush_main(int argc, char **argv)
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struct variable *shell_ver;
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INIT_G();
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if (EXIT_SUCCESS) /* if EXIT_SUCCESS == 0, it is already done */
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if (EXIT_SUCCESS != 0) /* if EXIT_SUCCESS == 0, it is already done */
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G.last_exitcode = EXIT_SUCCESS;
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#if ENABLE_HUSH_FAST
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G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
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#endif
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#if !BB_MMU
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G.argv0_for_re_execing = argv[0];
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#endif
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@ -8303,7 +8308,7 @@ static int FAST_FUNC builtin_trap(char **argv)
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/* There was a trap handler, we are removing it
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* (if sig has non-DFL handling,
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* we don't need to do anything) */
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if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
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if (sig < sizeof(G.special_sig_mask)*8 && (G.special_sig_mask & (1 << sig)))
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continue;
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sigdelset(&G.blocked_set, sig);
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}
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@ -8565,7 +8570,7 @@ static int FAST_FUNC builtin_read(char **argv)
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memset(&sa, 0, sizeof(sa));
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sigfillset(&sa.sa_mask);
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/*sa.sa_flags = 0;*/
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sa.sa_flags = SA_RESTART;
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sa.sa_handler = record_signal;
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sig = 0;
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@ -159,32 +159,40 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
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bufpos = 0;
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do {
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char c;
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errno = 0;
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if (end_ms) {
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int timeout;
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struct pollfd pfd[1];
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int timeout;
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pfd[0].fd = fd;
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pfd[0].events = POLLIN;
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if ((bufpos & 0xff) == 0)
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buffer = xrealloc(buffer, bufpos + 0x100);
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timeout = -1;
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if (end_ms) {
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timeout = end_ms - (unsigned)monotonic_ms();
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if (timeout <= 0 /* already late? */
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|| poll(pfd, 1, timeout) != 1 /* no? wait... */
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) { /* timed out! */
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err = errno;
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if (timeout <= 0) { /* already late? */
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retval = (const char *)(uintptr_t)1;
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goto ret;
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}
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}
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if ((bufpos & 0xff) == 0)
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buffer = xrealloc(buffer, bufpos + 0x100);
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if (nonblock_immune_read(fd, &buffer[bufpos], 1, /*loop_on_EINTR:*/ 0) != 1) {
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/* We must poll even if timeout is -1:
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* we want to be interrupted if signal arrives,
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* regardless of SA_RESTART-ness of that signal!
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*/
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errno = 0;
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pfd[0].fd = fd;
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pfd[0].events = POLLIN;
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if (poll(pfd, 1, timeout) != 1) {
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/* timed out, or EINTR */
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err = errno;
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retval = (const char *)(uintptr_t)1;
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goto ret;
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}
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if (read(fd, &buffer[bufpos], 1) != 1) {
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err = errno;
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retval = (const char *)(uintptr_t)1;
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break;
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}
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c = buffer[bufpos];
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if (c == '\0')
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continue;
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