X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fsignals.c;h=85e5c79494fe59a4680cf42bf47120be2693e3e7;hb=HEAD;hp=06c2e75dfdf6958d1b674d028b9a7fdcb9da9464;hpb=cb22974d773942d66da42b700b8bca0db27a0920;p=sliver-openvswitch.git diff --git a/lib/signals.c b/lib/signals.c index 06c2e75df..85e5c7949 100644 --- a/lib/signals.c +++ b/lib/signals.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2011, 2012 Nicira, Inc. + * Copyright (c) 2008, 2009, 2011, 2012, 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -39,138 +39,37 @@ VLOG_DEFINE_THIS_MODULE(signals); #define N_SIGNALS 32 #endif -struct signal { - struct sigaction saved_sa; - int signr; -}; - -static volatile sig_atomic_t signaled[N_SIGNALS]; - -static int fds[2]; - -static void signal_handler(int signr); - -/* Initializes the signals subsystem (if it is not already initialized). Calls - * exit() if initialization fails. - * - * Calling this function is optional; it will be called automatically by - * signal_start() if necessary. Calling it explicitly allows the client to - * prevent the process from exiting at an unexpected time. */ -void -signal_init(void) -{ - static bool inited; - if (!inited) { - inited = true; - xpipe_nonblocking(fds); - } -} - -/* Sets up a handler for 'signr' and returns a structure that represents it. - * - * Only one handler for a given signal may be registered at a time. */ -struct signal * -signal_register(int signr) -{ - struct sigaction sa; - struct signal *s; - - signal_init(); - - s = xmalloc(sizeof *s); - s->signr = signr; - - /* Set up signal handler. */ - ovs_assert(signr >= 1 && signr < N_SIGNALS); - memset(&sa, 0, sizeof sa); - sa.sa_handler = signal_handler; - sigemptyset(&sa.sa_mask); - sa.sa_flags = SA_RESTART; - xsigaction(signr, &sa, &s->saved_sa); - - return s; -} - -/* Unregisters the handler for 's', restores the signal handler that was in - * effect before signal_register() was called, and frees 's'. */ -void -signal_unregister(struct signal *s) -{ - if (s) { - xsigaction(s->signr, &s->saved_sa, NULL); - free(s); - } -} - -/* Returns true if signal 's' has been received since the last call to this - * function with argument 's'. */ -bool -signal_poll(struct signal *s) -{ - char buf[_POSIX_PIPE_BUF]; - ignore(read(fds[0], buf, sizeof buf)); - if (signaled[s->signr]) { - signaled[s->signr] = 0; - return true; - } - return false; -} - -/* Causes the next call to poll_block() to wake up when signal_poll(s) would - * return true. */ -void -signal_wait(struct signal *s) -{ - if (signaled[s->signr]) { - poll_immediate_wake(); - } else { - poll_fd_wait(fds[0], POLLIN); - } -} - -static void -signal_handler(int signr) -{ - if (signr >= 1 && signr < N_SIGNALS) { - ignore(write(fds[1], "", 1)); - signaled[signr] = true; - } -} - -/* Returns the name of signal 'signum' as a string. The string may be in a - * static buffer that is reused from one call to the next. +/* Returns the name of signal 'signum' as a string. The return value is either + * a statically allocated constant string or the 'bufsize'-byte buffer + * 'namebuf'. 'bufsize' should be at least SIGNAL_NAME_BUFSIZE. * * The string is probably a (possibly multi-word) description of the signal * (e.g. "Hangup") instead of just the stringified version of the macro * (e.g. "SIGHUP"). */ const char * -signal_name(int signum) +signal_name(int signum, char *namebuf, size_t bufsize) { - const char *name = NULL; -#ifdef HAVE_STRSIGNAL - name = strsignal(signum); -#endif - if (!name) { - static char buffer[7 + INT_STRLEN(int) + 1]; - sprintf(buffer, "signal %d", signum); - name = buffer; +#if HAVE_DECL_SYS_SIGLIST + if (signum >= 0 && signum < N_SIGNALS) { + const char *name = sys_siglist[signum]; + if (name) { + return name; + } } - return name; +#endif + + snprintf(namebuf, bufsize, "signal %d", signum); + return namebuf; } void xsigaction(int signum, const struct sigaction *new, struct sigaction *old) { if (sigaction(signum, new, old)) { - VLOG_FATAL("sigaction(%s) failed (%s)", - signal_name(signum), strerror(errno)); - } -} + char namebuf[SIGNAL_NAME_BUFSIZE]; -void -xsigprocmask(int how, const sigset_t *new, sigset_t *old) -{ - if (sigprocmask(how, new, old)) { - VLOG_FATAL("sigprocmask failed (%s)", strerror(errno)); + VLOG_FATAL("sigaction(%s) failed (%s)", + signal_name(signum, namebuf, sizeof namebuf), + ovs_strerror(errno)); } }