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Diffstat (limited to 'threadproc/unix/signals.c')
| -rw-r--r-- | threadproc/unix/signals.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/threadproc/unix/signals.c b/threadproc/unix/signals.c new file mode 100644 index 0000000..c735eab --- /dev/null +++ b/threadproc/unix/signals.c @@ -0,0 +1,481 @@ +/* Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#define INCL_DOSEXCEPTIONS /* for OS2 */ +#include "apr_arch_threadproc.h" +#include "apr_private.h" +#include "apr_pools.h" +#include "apr_signal.h" +#include "apr_strings.h" + +#include <assert.h> +#if APR_HAS_THREADS && APR_HAVE_PTHREAD_H +#include <pthread.h> +#endif + +#ifdef SIGWAIT_TAKES_ONE_ARG +#define apr_sigwait(a,b) ((*(b)=sigwait((a)))<0?-1:0) +#else +#define apr_sigwait(a,b) sigwait((a),(b)) +#endif + +APR_DECLARE(apr_status_t) apr_proc_kill(apr_proc_t *proc, int signum) +{ +#ifdef OS2 + /* SIGTERM's don't work too well in OS/2 (only affects other EMX + * programs). CGIs may not be, esp. REXX scripts, so use a native + * call instead + */ + if (signum == SIGTERM) { + return APR_OS2_STATUS(DosSendSignalException(proc->pid, + XCPT_SIGNAL_BREAK)); + } +#endif /* OS2 */ + + if (kill(proc->pid, signum) == -1) { + return errno; + } + + return APR_SUCCESS; +} + + +#if APR_HAVE_SIGACTION + +#if defined(__NetBSD__) || defined(DARWIN) +static void avoid_zombies(int signo) +{ + int exit_status; + + while (waitpid(-1, &exit_status, WNOHANG) > 0) { + /* do nothing */ + } +} +#endif /* DARWIN */ + +/* + * Replace standard signal() with the more reliable sigaction equivalent + * from W. Richard Stevens' "Advanced Programming in the UNIX Environment" + * (the version that does not automatically restart system calls). + */ +APR_DECLARE(apr_sigfunc_t *) apr_signal(int signo, apr_sigfunc_t * func) +{ + struct sigaction act, oact; + + act.sa_handler = func; + sigemptyset(&act.sa_mask); + act.sa_flags = 0; +#ifdef SA_INTERRUPT /* SunOS */ + act.sa_flags |= SA_INTERRUPT; +#endif +#if defined(__osf__) && defined(__alpha) + /* XXX jeff thinks this should be enabled whenever SA_NOCLDWAIT is defined */ + + /* this is required on Tru64 to cause child processes to + * disappear gracefully - XPG4 compatible + */ + if ((signo == SIGCHLD) && (func == SIG_IGN)) { + act.sa_flags |= SA_NOCLDWAIT; + } +#endif +#if defined(__NetBSD__) || defined(DARWIN) + /* ignoring SIGCHLD or leaving the default disposition doesn't avoid zombies, + * and there is no SA_NOCLDWAIT flag, so catch the signal and reap status in + * the handler to avoid zombies + */ + if ((signo == SIGCHLD) && (func == SIG_IGN)) { + act.sa_handler = avoid_zombies; + } +#endif + if (sigaction(signo, &act, &oact) < 0) + return SIG_ERR; + return oact.sa_handler; +} + +#endif /* HAVE_SIGACTION */ + +/* AC_DECL_SYS_SIGLIST defines either of these symbols depending + * on the version of autoconf used. */ +#if defined(SYS_SIGLIST_DECLARED) || HAVE_DECL_SYS_SIGLIST + +void apr_signal_init(apr_pool_t *pglobal) +{ +} +const char *apr_signal_description_get(int signum) +{ + return (signum >= 0) ? sys_siglist[signum] : "unknown signal (number)"; +} + +#else /* !(SYS_SIGLIST_DECLARED || HAVE_DECL_SYS_SIGLIST) */ + +/* we need to roll our own signal description stuff */ + +#if defined(NSIG) +#define APR_NUMSIG NSIG +#elif defined(_NSIG) +#define APR_NUMSIG _NSIG +#elif defined(__NSIG) +#define APR_NUMSIG __NSIG +#else +#define APR_NUMSIG 33 /* breaks on OS/390 with < 33; 32 is o.k. for most */ +#endif + +static const char *signal_description[APR_NUMSIG]; + +#define store_desc(index, string) \ + do { \ + if (index >= APR_NUMSIG) { \ + assert(index < APR_NUMSIG); \ + } \ + else { \ + signal_description[index] = string; \ + } \ + } while (0) + +void apr_signal_init(apr_pool_t *pglobal) +{ + int sig; + + store_desc(0, "Signal 0"); + +#ifdef SIGHUP + store_desc(SIGHUP, "Hangup"); +#endif +#ifdef SIGINT + store_desc(SIGINT, "Interrupt"); +#endif +#ifdef SIGQUIT + store_desc(SIGQUIT, "Quit"); +#endif +#ifdef SIGILL + store_desc(SIGILL, "Illegal instruction"); +#endif +#ifdef SIGTRAP + store_desc(SIGTRAP, "Trace/BPT trap"); +#endif +#ifdef SIGIOT + store_desc(SIGIOT, "IOT instruction"); +#endif +#ifdef SIGABRT + store_desc(SIGABRT, "Abort"); +#endif +#ifdef SIGEMT + store_desc(SIGEMT, "Emulator trap"); +#endif +#ifdef SIGFPE + store_desc(SIGFPE, "Arithmetic exception"); +#endif +#ifdef SIGKILL + store_desc(SIGKILL, "Killed"); +#endif +#ifdef SIGBUS + store_desc(SIGBUS, "Bus error"); +#endif +#ifdef SIGSEGV + store_desc(SIGSEGV, "Segmentation fault"); +#endif +#ifdef SIGSYS + store_desc(SIGSYS, "Bad system call"); +#endif +#ifdef SIGPIPE + store_desc(SIGPIPE, "Broken pipe"); +#endif +#ifdef SIGALRM + store_desc(SIGALRM, "Alarm clock"); +#endif +#ifdef SIGTERM + store_desc(SIGTERM, "Terminated"); +#endif +#ifdef SIGUSR1 + store_desc(SIGUSR1, "User defined signal 1"); +#endif +#ifdef SIGUSR2 + store_desc(SIGUSR2, "User defined signal 2"); +#endif +#ifdef SIGCLD + store_desc(SIGCLD, "Child status change"); +#endif +#ifdef SIGCHLD + store_desc(SIGCHLD, "Child status change"); +#endif +#ifdef SIGPWR + store_desc(SIGPWR, "Power-fail restart"); +#endif +#ifdef SIGWINCH + store_desc(SIGWINCH, "Window changed"); +#endif +#ifdef SIGURG + store_desc(SIGURG, "urgent socket condition"); +#endif +#ifdef SIGPOLL + store_desc(SIGPOLL, "Pollable event occurred"); +#endif +#ifdef SIGIO + store_desc(SIGIO, "socket I/O possible"); +#endif +#ifdef SIGSTOP + store_desc(SIGSTOP, "Stopped (signal)"); +#endif +#ifdef SIGTSTP + store_desc(SIGTSTP, "Stopped"); +#endif +#ifdef SIGCONT + store_desc(SIGCONT, "Continued"); +#endif +#ifdef SIGTTIN + store_desc(SIGTTIN, "Stopped (tty input)"); +#endif +#ifdef SIGTTOU + store_desc(SIGTTOU, "Stopped (tty output)"); +#endif +#ifdef SIGVTALRM + store_desc(SIGVTALRM, "virtual timer expired"); +#endif +#ifdef SIGPROF + store_desc(SIGPROF, "profiling timer expired"); +#endif +#ifdef SIGXCPU + store_desc(SIGXCPU, "exceeded cpu limit"); +#endif +#ifdef SIGXFSZ + store_desc(SIGXFSZ, "exceeded file size limit"); +#endif + + for (sig = 0; sig < APR_NUMSIG; ++sig) + if (signal_description[sig] == NULL) + signal_description[sig] = apr_psprintf(pglobal, "signal #%d", sig); +} + +const char *apr_signal_description_get(int signum) +{ + return + (signum >= 0 && signum < APR_NUMSIG) + ? signal_description[signum] + : "unknown signal (number)"; +} + +#endif /* SYS_SIGLIST_DECLARED || HAVE_DECL_SYS_SIGLIST */ + +#if APR_HAS_THREADS && (HAVE_SIGSUSPEND || APR_HAVE_SIGWAIT) && !defined(OS2) + +static void remove_sync_sigs(sigset_t *sig_mask) +{ +#ifdef SIGABRT + sigdelset(sig_mask, SIGABRT); +#endif +#ifdef SIGBUS + sigdelset(sig_mask, SIGBUS); +#endif +#ifdef SIGEMT + sigdelset(sig_mask, SIGEMT); +#endif +#ifdef SIGFPE + sigdelset(sig_mask, SIGFPE); +#endif +#ifdef SIGILL + sigdelset(sig_mask, SIGILL); +#endif +#ifdef SIGIOT + sigdelset(sig_mask, SIGIOT); +#endif +#ifdef SIGPIPE + sigdelset(sig_mask, SIGPIPE); +#endif +#ifdef SIGSEGV + sigdelset(sig_mask, SIGSEGV); +#endif +#ifdef SIGSYS + sigdelset(sig_mask, SIGSYS); +#endif +#ifdef SIGTRAP + sigdelset(sig_mask, SIGTRAP); +#endif + +/* the rest of the signals removed from the mask in this function + * absolutely must be removed; you cannot block synchronous signals + * (requirement of pthreads API) + */ +} + +APR_DECLARE(apr_status_t) apr_signal_thread(int(*signal_handler)(int signum)) +{ + sigset_t sig_mask; +#if APR_HAVE_SIGWAIT + int (*sig_func)(int signum) = (int (*)(int))signal_handler; +#endif + + /* This thread will be the one responsible for handling signals */ + sigfillset(&sig_mask); + + /* On certain platforms, sigwait() returns EINVAL if any of various + * unblockable signals are included in the mask. This was first + * observed on AIX and Tru64. + */ +#ifdef SIGKILL + sigdelset(&sig_mask, SIGKILL); +#endif +#ifdef SIGSTOP + sigdelset(&sig_mask, SIGSTOP); +#endif +#ifdef SIGCONT + sigdelset(&sig_mask, SIGCONT); +#endif +#ifdef SIGWAITING + sigdelset(&sig_mask, SIGWAITING); +#endif + + /* no synchronous signals should be in the mask passed to sigwait() */ + remove_sync_sigs(&sig_mask); + + /* On AIX (4.3.3, at least), sigwait() won't wake up if the high- + * order bit of the second word of flags is turned on. sigdelset() + * returns an error when trying to turn this off, so we'll turn it + * off manually. + * + * Note that the private fields differ between 32-bit and 64-bit + * and even between _ALL_SOURCE and !_ALL_SOURCE. Except that on + * AIX 4.3 32-bit builds and 64-bit builds use the same definition. + * + * Applicable AIX fixes such that this is no longer needed: + * + * APAR IY23096 for AIX 51B, fix included in AIX 51C, and + * APAR IY24162 for 43X. + */ +#if defined(_AIX) +#if defined(__64BIT__) && defined(_AIXVERSION_510) +#ifdef _ALL_SOURCE + sig_mask.ss_set[3] &= 0x7FFFFFFF; +#else /* not _ALL_SOURCE */ + sig_mask.__ss_set[3] &= 0x7FFFFFFF; +#endif +#else /* not 64-bit build, or 64-bit build on 4.3 */ +#ifdef _ALL_SOURCE + sig_mask.hisigs &= 0x7FFFFFFF; +#else /* not _ALL_SOURCE */ + sig_mask.__hisigs &= 0x7FFFFFFF; +#endif +#endif +#endif /* _AIX */ + + while (1) { +#if APR_HAVE_SIGWAIT + int signal_received; + + if (apr_sigwait(&sig_mask, &signal_received) != 0) + { + /* handle sigwait() error here */ + } + + if (sig_func(signal_received) == 1) { + return APR_SUCCESS; + } +#elif HAVE_SIGSUSPEND + sigsuspend(&sig_mask); +#else +#error No apr_sigwait() and no sigsuspend() +#endif + } +} + +APR_DECLARE(apr_status_t) apr_setup_signal_thread(void) +{ + sigset_t sig_mask; + int rv; + + /* All threads should mask out signals to be handled by + * the thread doing sigwait(). + * + * No thread should ever block synchronous signals. + * See the Solaris man page for pthread_sigmask() for + * some information. Solaris chooses to knock out such + * processes when a blocked synchronous signal is + * delivered, skipping any registered signal handler. + * AIX doesn't call a signal handler either. At least + * one level of linux+glibc does call the handler even + * when the synchronous signal is blocked. + */ + sigfillset(&sig_mask); + remove_sync_sigs(&sig_mask); + +#if defined(SIGPROCMASK_SETS_THREAD_MASK) || ! APR_HAS_THREADS + if ((rv = sigprocmask(SIG_SETMASK, &sig_mask, NULL)) != 0) { + rv = errno; + } +#else + if ((rv = pthread_sigmask(SIG_SETMASK, &sig_mask, NULL)) != 0) { +#ifdef HAVE_ZOS_PTHREADS + rv = errno; +#endif + } +#endif + return rv; +} + +#endif /* APR_HAS_THREADS && ... */ + +APR_DECLARE(apr_status_t) apr_signal_block(int signum) +{ +#if APR_HAVE_SIGACTION + sigset_t sig_mask; + int rv; + + sigemptyset(&sig_mask); + + sigaddset(&sig_mask, signum); + +#if defined(SIGPROCMASK_SETS_THREAD_MASK) || ! APR_HAS_THREADS + if ((rv = sigprocmask(SIG_BLOCK, &sig_mask, NULL)) != 0) { + rv = errno; + } +#else + if ((rv = pthread_sigmask(SIG_BLOCK, &sig_mask, NULL)) != 0) { +#ifdef HAVE_ZOS_PTHREADS + rv = errno; +#endif + } +#endif + return rv; +#else + return APR_ENOTIMPL; +#endif +} + +APR_DECLARE(apr_status_t) apr_signal_unblock(int signum) +{ +#if APR_HAVE_SIGACTION + sigset_t sig_mask; + int rv; + + sigemptyset(&sig_mask); + + sigaddset(&sig_mask, signum); + +#if defined(SIGPROCMASK_SETS_THREAD_MASK) || ! APR_HAS_THREADS + if ((rv = sigprocmask(SIG_UNBLOCK, &sig_mask, NULL)) != 0) { + rv = errno; + } +#else + if ((rv = pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL)) != 0) { +#ifdef HAVE_ZOS_PTHREADS + rv = errno; +#endif + } +#endif + return rv; +#else + return APR_ENOTIMPL; +#endif +} |