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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 | /* Linuxthreads - a simple clone()-based implementation of Posix */ /* threads for Linux. */ /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ /* */ /* This program is free software; you can redistribute it and/or */ /* modify it under the terms of the GNU Library General Public License */ /* as published by the Free Software Foundation; either version 2 */ /* of the License, or (at your option) any later version. */ /* */ /* This program is distributed in the hope that it will be useful, */ /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ /* GNU Library General Public License for more details. */ /* Handling of signals */ #include <errno.h> #include <signal.h> #include <stdio.h> #include <sys/syscall.h> #include "pthread.h" #include "internals.h" #include "spinlock.h" #include <bits/sigcontextinfo.h> int pthread_sigmask(int how, const sigset_t * newmask, sigset_t * oldmask) { sigset_t mask; if (newmask != NULL) { mask = *newmask; /* Don't allow __pthread_sig_restart to be unmasked. Don't allow __pthread_sig_cancel to be masked. */ switch(how) { case SIG_SETMASK: sigaddset(&mask, __pthread_sig_restart); sigdelset(&mask, __pthread_sig_cancel); if (__pthread_sig_debug > 0) sigdelset(&mask, __pthread_sig_debug); break; case SIG_BLOCK: sigdelset(&mask, __pthread_sig_cancel); if (__pthread_sig_debug > 0) sigdelset(&mask, __pthread_sig_debug); break; case SIG_UNBLOCK: sigdelset(&mask, __pthread_sig_restart); break; } newmask = &mask; } if (sigprocmask(how, newmask, oldmask) == -1) return errno; else return 0; } int pthread_kill(pthread_t thread, int signo) { pthread_handle handle = thread_handle(thread); int pid; __pthread_lock(&handle->h_lock, NULL); if (invalid_handle(handle, thread)) { __pthread_unlock(&handle->h_lock); return ESRCH; } pid = handle->h_descr->p_pid; __pthread_unlock(&handle->h_lock); if (kill(pid, signo) == -1) return errno; else return 0; } /* User-provided signal handlers */ typedef void (*arch_sighandler_t) __PMT ((int, SIGCONTEXT)); static union { arch_sighandler_t old; void (*rt) (int, struct siginfo *, struct ucontext *); } sighandler[NSIG]; /* The wrapper around user-provided signal handlers */ static void pthread_sighandler(int signo, SIGCONTEXT ctx) { pthread_descr self = thread_self(); char * in_sighandler; /* If we're in a sigwait operation, just record the signal received and return without calling the user's handler */ if (THREAD_GETMEM(self, p_sigwaiting)) { THREAD_SETMEM(self, p_sigwaiting, 0); THREAD_SETMEM(self, p_signal, signo); return; } /* Record that we're in a signal handler and call the user's handler function */ in_sighandler = THREAD_GETMEM(self, p_in_sighandler); if (in_sighandler == NULL) THREAD_SETMEM(self, p_in_sighandler, CURRENT_STACK_FRAME); sighandler[signo].old(signo, SIGCONTEXT_EXTRA_ARGS ctx); if (in_sighandler == NULL) THREAD_SETMEM(self, p_in_sighandler, NULL); } /* The same, this time for real-time signals. */ static void pthread_sighandler_rt(int signo, struct siginfo *si, struct ucontext *uc) { pthread_descr self = thread_self(); char * in_sighandler; /* If we're in a sigwait operation, just record the signal received and return without calling the user's handler */ if (THREAD_GETMEM(self, p_sigwaiting)) { THREAD_SETMEM(self, p_sigwaiting, 0); THREAD_SETMEM(self, p_signal, signo); return; } /* Record that we're in a signal handler and call the user's handler function */ in_sighandler = THREAD_GETMEM(self, p_in_sighandler); if (in_sighandler == NULL) THREAD_SETMEM(self, p_in_sighandler, CURRENT_STACK_FRAME); sighandler[signo].rt(signo, si, uc); if (in_sighandler == NULL) THREAD_SETMEM(self, p_in_sighandler, NULL); } /* The wrapper around sigaction. Install our own signal handler around the signal. */ libpthread_hidden_proto(sigaction) int sigaction(int sig, const struct sigaction * act, struct sigaction * oact) { struct sigaction newact; struct sigaction *newactp; void *save = NULL; #ifdef DEBUG_PT printf(__FUNCTION__": pthreads wrapper!\n"); #endif if (sig == __pthread_sig_restart || sig == __pthread_sig_cancel || (sig == __pthread_sig_debug && __pthread_sig_debug > 0)) return EINVAL; if (sig > 0 && sig < NSIG) save = sighandler[sig].old; if (act) { newact = *act; if (act->sa_handler != SIG_IGN && act->sa_handler != SIG_DFL && sig > 0 && sig < NSIG) { if (act->sa_flags & SA_SIGINFO) newact.sa_handler = (__sighandler_t) pthread_sighandler_rt; else newact.sa_handler = (__sighandler_t) pthread_sighandler; } newactp = &newact; if (sig > 0 && sig < NSIG) sighandler[sig].old = (arch_sighandler_t) act->sa_handler; } else newactp = NULL; if (__libc_sigaction(sig, newactp, oact) == -1) { if (act && sig > 0 && sig < NSIG) sighandler[sig].old = save; return -1; } #ifdef DEBUG_PT printf(__FUNCTION__": sighandler installed, sigaction successful\n"); #endif if (sig > 0 && sig < NSIG) { if (oact != NULL) oact->sa_handler = save; } return 0; } libpthread_hidden_def(sigaction) /* A signal handler that does nothing */ static void pthread_null_sighandler(int sig attribute_unused) { } /* sigwait -- synchronously wait for a signal */ int sigwait(const sigset_t * set, int * sig) { volatile pthread_descr self = thread_self(); sigset_t mask; int s; sigjmp_buf jmpbuf; struct sigaction sa; /* Get ready to block all signals except those in set and the cancellation signal. Also check that handlers are installed on all signals in set, and if not, install our dummy handler. This is conformant to POSIX: "The effect of sigwait() on the signal actions for the signals in set is unspecified." */ __sigfillset(&mask); sigdelset(&mask, __pthread_sig_cancel); for (s = 1; s <= NSIG; s++) { if (sigismember(set, s) && s != __pthread_sig_restart && s != __pthread_sig_cancel && s != __pthread_sig_debug) { sigdelset(&mask, s); if (sighandler[s].old == NULL || sighandler[s].old == (arch_sighandler_t) SIG_DFL || sighandler[s].old == (arch_sighandler_t) SIG_IGN) { memset(&sa, 0, sizeof(sa)); sa.sa_handler = pthread_null_sighandler; sigaction(s, &sa, NULL); } } } /* Test for cancellation */ if (sigsetjmp(jmpbuf, 1) == 0) { THREAD_SETMEM(self, p_cancel_jmp, &jmpbuf); if (! (THREAD_GETMEM(self, p_canceled) && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE)) { /* Reset the signal count */ THREAD_SETMEM(self, p_signal, 0); /* Say we're in sigwait */ THREAD_SETMEM(self, p_sigwaiting, 1); /* Unblock the signals and wait for them */ sigsuspend(&mask); } } THREAD_SETMEM(self, p_cancel_jmp, NULL); /* The signals are now reblocked. Check for cancellation */ pthread_testcancel(); /* We should have self->p_signal != 0 and equal to the signal received */ *sig = THREAD_GETMEM(self, p_signal); return 0; } /* Redefine raise() to send signal to calling thread only, as per POSIX 1003.1c */ libpthread_hidden_proto(raise) int raise (int sig) { int ret; pid_t tid; tid = INLINE_SYSCALL(gettid, 0); ret = INLINE_SYSCALL(tkill, 2, tid, sig); return ret; } libpthread_hidden_def(raise) |