From 10c0131a8a1b3db7fd6b23b72ebd7b33afc7b018 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Wed, 11 May 2011 11:49:21 +0200 Subject: hush: use SA_RESTARTed signal handlers across read. Signed-off-by: Denys Vlasenko --- shell/hush.c | 37 +++++++++++++++++++++---------------- shell/shell_common.c | 34 +++++++++++++++++++++------------- 2 files changed, 42 insertions(+), 29 deletions(-) (limited to 'shell') diff --git a/shell/hush.c b/shell/hush.c index 71972f751..509bd415b 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -792,8 +792,13 @@ struct globals { 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 @@ static void restore_G_args(save_arg_t *sv, char **argv) * 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 @@ static void reset_traps_to_defaults(void) * 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 @@ static void reset_traps_to_defaults(void) } } /* 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 @@ static void init_sigmasks(void) /* 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 @@ static void init_sigmasks(void) 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 @@ static void set_fatal_handlers_to_sigexit(void) /*+ (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 @@ int hush_main(int argc, char **argv) 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 @@ static int FAST_FUNC builtin_trap(char **argv) /* 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 @@ static int FAST_FUNC builtin_read(char **argv) 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 a5c455c8e..bbc22ed34 100644 --- a/shell/shell_common.c +++ b/shell/shell_common.c @@ -159,32 +159,40 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val), 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; -- cgit v1.2.3