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author | jkh <jkh@FreeBSD.org> | 1993-06-18 05:46:17 +0000 |
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committer | jkh <jkh@FreeBSD.org> | 1993-06-18 05:46:17 +0000 |
commit | 77629e160d558a58cca8b90f395ec5eba88b6bf0 (patch) | |
tree | 3595c61e4f85a1d3c1fb6ea6c1ede9ea8397ced7 /gnu/usr.bin/cvs/lib/sighandle.c | |
download | FreeBSD-src-77629e160d558a58cca8b90f395ec5eba88b6bf0.zip FreeBSD-src-77629e160d558a58cca8b90f395ec5eba88b6bf0.tar.gz |
Updated CVS
Diffstat (limited to 'gnu/usr.bin/cvs/lib/sighandle.c')
-rw-r--r-- | gnu/usr.bin/cvs/lib/sighandle.c | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/gnu/usr.bin/cvs/lib/sighandle.c b/gnu/usr.bin/cvs/lib/sighandle.c new file mode 100644 index 0000000..1b73b93 --- /dev/null +++ b/gnu/usr.bin/cvs/lib/sighandle.c @@ -0,0 +1,412 @@ +/* sighandle.c -- Library routines for manipulating chains of signal handlers + Copyright (C) 1992 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +/* Written by Paul Sander, HaL Computer Systems, Inc. <paul@hal.com> + Brian Berliner <berliner@Sun.COM> added POSIX support */ + +/************************************************************************* + * + * signal.c -- This file contains code that manipulates chains of signal + * handlers. + * + * Facilities are provided to register a signal handler for + * any specific signal. When a signal is received, all of the + * registered signal handlers are invoked in the reverse order + * in which they are registered. Note that the signal handlers + * must not themselves make calls to the signal handling + * facilities. + * + * @(#)sighandle.c 1.9 92/03/31 + * + *************************************************************************/ + +#include <sys/types.h> +#include <stdio.h> +#include <signal.h> + +#ifdef STDC_HEADERS +#include <stdlib.h> +#else +#if __STDC__ +char *calloc(unsigned nelem, unsigned size); +char *malloc(unsigned size); +#else +char *calloc(); +char *malloc(); +#endif /* __STDC__ */ +#endif /* STDC_HEADERS */ + +#ifdef _MINIX +#undef POSIX /* Minix 1.6 doesn't support POSIX.1 sigaction yet */ +#endif + +#ifndef SIGTYPE +#define SIGTYPE void +#endif + +/* Define the highest signal number (usually) */ +#ifndef SIGMAX +#define SIGMAX 32 +#endif + +/* Define linked list of signal handlers structure */ +struct SIG_hlist { + SIGTYPE (*handler)(); + struct SIG_hlist *next; +}; + +/* + * Define array of lists of signal handlers. Note that this depends on + * the implementation to initialize each element to a null pointer. + */ + +static struct SIG_hlist **SIG_handlers; + +/* Define array of default signal vectors */ + +#ifdef POSIX +static struct sigaction *SIG_defaults; +#else +#ifdef BSD_SIGNALS +static struct sigvec *SIG_defaults; +#else +static SIGTYPE (**SIG_defaults)(); +#endif +#endif + +/* Critical section housekeeping */ +static int SIG_crSectNest = 0; /* Nesting level */ +#ifdef POSIX +static sigset_t SIG_crSectMask; /* Signal mask */ +#else +static int SIG_crSectMask; /* Signal mask */ +#endif + +/* + * Initialize the signal handler arrays + */ + +static int SIG_init() +{ + int i; +#ifdef POSIX + sigset_t sigset_test; +#endif + + if (SIG_defaults && SIG_handlers) /* already allocated */ + return (0); + +#ifdef POSIX + (void) sigfillset(&sigset_test); + for (i = 1; sigismember(&sigset_test, i) == 1; i++) +#ifdef BROKEN_SIGISMEMBER + if ( i >= NSIG ) + break +#endif + ; + if (i < SIGMAX) + i = SIGMAX; + i++; + if (!SIG_defaults) + SIG_defaults = (struct sigaction *) + calloc(i, sizeof(struct sigaction)); + (void) sigemptyset(&SIG_crSectMask); +#else + i = SIGMAX+1; +#ifdef BSD_SIGNALS + if (!SIG_defaults) + SIG_defaults = (struct sigvec *) + calloc(i, sizeof(struct sigvec)); +#else + if (!SIG_defaults) + SIG_defaults = (SIGTYPE (**)()) + calloc(i, sizeof(SIGTYPE (**)())); +#endif + SIG_crSectMask = 0; +#endif + if (!SIG_handlers) + SIG_handlers = (struct SIG_hlist **) + calloc(i, sizeof(struct SIG_hlist *)); + return (!SIG_defaults || !SIG_handlers); +} + +/* + * The following invokes each signal handler in the reverse order in which + * they were registered. + */ + +static SIGTYPE SIG_handle(sig) +int sig; +{ + struct SIG_hlist *this; + + /* Dispatch signal handlers */ + this = SIG_handlers[sig]; + while (this != (struct SIG_hlist *) NULL) + { + (*this->handler)(sig); + this = this->next; + } + + return; +} + +/* + * The following registers a signal handler. If the handler is already + * registered, it is not registered twice, nor is the order in which signal + * handlers are invoked changed. If this is the first signal handler + * registered for a given signal, the old sigvec structure is saved for + * restoration later. + */ + +int SIG_register(sig,fn) +int sig; +SIGTYPE (*fn)(); +{ + int val; + struct SIG_hlist *this; +#ifdef POSIX + struct sigaction act; + sigset_t sigset_mask, sigset_omask; +#else +#ifdef BSD_SIGNALS + struct sigvec vec; + int mask; +#endif +#endif + + /* Initialize */ + if (SIG_init() != 0) + return (-1); + val = 0; + + /* Block this signal while we look at handler chain */ +#ifdef POSIX + (void) sigemptyset(&sigset_mask); + (void) sigaddset(&sigset_mask, sig); + (void) sigprocmask(SIG_BLOCK, &sigset_mask, &sigset_omask); +#else +#ifdef BSD_SIGNALS + mask = sigblock(sigmask(sig)); +#endif +#endif + + /* See if this handler was already registered */ + this = SIG_handlers[sig]; + while (this != (struct SIG_hlist *) NULL) + { + if (this->handler == fn) break; + this = this->next; + } + + /* Register the new handler only if it is not already registered. */ + if (this == (struct SIG_hlist *) NULL) + { + + /* + * If this is the first handler registered for this signal, + * set up the signal handler dispatcher + */ + + if (SIG_handlers[sig] == (struct SIG_hlist *) NULL) + { +#ifdef POSIX + act.sa_handler = SIG_handle; + (void) sigemptyset(&act.sa_mask); + act.sa_flags = 0; + val = sigaction(sig, &act, &SIG_defaults[sig]); +#else +#ifdef BSD_SIGNALS + bzero((char *)&vec, sizeof(vec)); + vec.sv_handler = SIG_handle; + val = sigvec(sig, &vec, &SIG_defaults[sig]); +#else + if ((SIG_defaults[sig] = signal(sig, SIG_handle)) == + (SIGTYPE (*)()) -1) + val = -1; +#endif +#endif + } + + /* If not, register it */ + if ((val == 0) && (this == (struct SIG_hlist *) NULL)) + { + this = (struct SIG_hlist *) + malloc(sizeof(struct SIG_hlist)); + if (this == NULL) + { + val = -1; + } + else + { + this->handler = fn; + this->next = SIG_handlers[sig]; + SIG_handlers[sig] = this; + } + } + } + + /* Unblock the signal */ +#ifdef POSIX + (void) sigprocmask(SIG_SETMASK, &sigset_omask, NULL); +#else +#ifdef BSD_SIGNALS + (void) sigsetmask(mask); +#endif +#endif + + return val; +} + +/* + * The following deregisters a signal handler. If the last signal handler for + * a given signal is deregistered, the default sigvec information is restored. + */ + +int SIG_deregister(sig,fn) +int sig; +SIGTYPE (*fn)(); +{ + int val; + struct SIG_hlist *this; + struct SIG_hlist *last; +#ifdef POSIX + sigset_t sigset_mask, sigset_omask; +#else +#ifdef BSD_SIGNALS + int mask; +#endif +#endif + + /* Initialize */ + if (SIG_init() != 0) + return (-1); + val = 0; + last = (struct SIG_hlist *) NULL; + + /* Block this signal while we look at handler chain */ +#ifdef POSIX + (void) sigemptyset(&sigset_mask); + (void) sigaddset(&sigset_mask, sig); + (void) sigprocmask(SIG_BLOCK, &sigset_mask, &sigset_omask); +#else +#ifdef BSD_SIGNALS + mask = sigblock(sigmask(sig)); +#endif +#endif + + /* Search for the signal handler */ + this = SIG_handlers[sig]; + while ((this != (struct SIG_hlist *) NULL) && (this->handler != fn)) + { + last = this; + this = this->next; + } + + /* If it was registered, remove it */ + if (this != (struct SIG_hlist *) NULL) + { + if (last == (struct SIG_hlist *) NULL) + { + SIG_handlers[sig] = this->next; + } + else + { + last->next = this->next; + } + free((char *) this); + } + + /* Restore default behavior if there are no registered handlers */ + if (SIG_handlers[sig] == (struct SIG_hlist *) NULL) + { +#ifdef POSIX + val = sigaction(sig, &SIG_defaults[sig], + (struct sigaction *) NULL); +#else +#ifdef BSD_SIGNALS + val = sigvec(sig, &SIG_defaults[sig], (struct sigvec *) NULL); +#else + if (signal(sig, SIG_defaults[sig]) == (SIGTYPE (*)()) -1) + val = -1; +#endif +#endif + } + + /* Unblock the signal */ +#ifdef POSIX + (void) sigprocmask(SIG_SETMASK, &sigset_omask, NULL); +#else +#ifdef BSD_SIGNALS + (void) sigsetmask(mask); +#endif +#endif + + return val; +} + +/* + * The following begins a critical section. + */ + +void SIG_beginCrSect() +{ + if (SIG_init() == 0) + { + if (SIG_crSectNest == 0) + { +#ifdef POSIX + sigset_t sigset_mask; + + (void) sigfillset(&sigset_mask); + (void) sigprocmask(SIG_SETMASK, + &sigset_mask, &SIG_crSectMask); +#else +#ifdef BSD_SIGNALS + SIG_crSectMask = sigblock(~0); +#else + /* TBD */ +#endif +#endif + } + SIG_crSectNest++; + } +} + +/* + * The following ends a critical section. + */ + +void SIG_endCrSect() +{ + if (SIG_init() == 0) + { + SIG_crSectNest--; + if (SIG_crSectNest == 0) + { +#ifdef POSIX + (void) sigprocmask(SIG_SETMASK, &SIG_crSectMask, NULL); +#else +#ifdef BSD_SIGNALS + (void) sigsetmask(SIG_crSectMask); +#else + /* TBD */ +#endif +#endif + } + } +} |