projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 7baad5ae C |
1 | /* signal.c: a Hugh-approved signal handler. */ |
| 2 | ||
| 3 | #include <signal.h> | |
| 4 | #include <setjmp.h> | |
| 5 | #include "rc.h" | |
| 6 | #include "sigmsgs.h" | |
| 7 | #include "jbwrap.h" | |
| 8 | ||
| 9 | Jbwrap slowbuf; | |
| 10 | volatile SIG_ATOMIC_T slow, interrupt_happened; | |
| 11 | void (*sighandlers[NUMOFSIGNALS])(int); | |
| 12 | ||
| 13 | static volatile SIG_ATOMIC_T sigcount, caught[NUMOFSIGNALS]; | |
| 14 | ||
| 15 | extern void catcher(int s) { | |
| 16 | if (forked) | |
| 17 | exit(1); /* exit unconditionally on a signal in a child process */ | |
| 18 | if (caught[s] == 0) { | |
| 19 | sigcount++; | |
| 20 | caught[s] = 1; | |
| 21 | } | |
| 22 | signal(s, catcher); | |
| 23 | interrupt_happened = TRUE; | |
| 24 | if (slow) | |
| 25 | longjmp(slowbuf.j, 1); | |
| 26 | } | |
| 27 | ||
| 28 | extern void sigchk() { | |
| 29 | void (*h)(int); | |
| 30 | int s, i; | |
| 31 | if (sigcount == 0) | |
| 32 | return; /* ho hum; life as usual */ | |
| 33 | if (forked) | |
| 34 | exit(1); /* exit unconditionally on a signal in a child process */ | |
| 35 | for (i = 0, s = -1; i < NUMOFSIGNALS; i++) | |
| 36 | if (caught[i] != 0) { | |
| 37 | s = i; | |
| 38 | --sigcount; | |
| 39 | caught[s] = 0; | |
| 40 | break; | |
| 41 | } | |
| 42 | if (s == -1) | |
| 43 | panic("all-zero sig vector with nonzero sigcount"); | |
| 44 | if ((h = sighandlers[s]) == SIG_DFL) | |
| 45 | panic("caught signal set to SIG_DFL"); | |
| 46 | if (h == SIG_IGN) | |
| 47 | panic("caught signal set to SIG_IGN"); | |
| 48 | (*h)(s); | |
| 49 | } | |
| 50 | ||
| 51 | extern void (*rc_signal(int s, void (*h)(int)))(int) { | |
| 52 | void (*old)(int); | |
| 53 | SIGCHK; | |
| 54 | old = sighandlers[s]; | |
| 55 | if (h == SIG_DFL || h == SIG_IGN) { | |
| 56 | signal(s, h); | |
| 57 | sighandlers[s] = h; | |
| 58 | } else { | |
| 59 | sighandlers[s] = h; | |
| 60 | signal(s, catcher); | |
| 61 | } | |
| 62 | return old; | |
| 63 | } | |
| 64 | ||
| 65 | extern void initsignal() { | |
| 66 | void (*h)(int); | |
| 67 | int i; | |
| 68 | for (i = 1; i < NUMOFSIGNALS; i++) { | |
| 69 | if ((h = signal(i, SIG_DFL)) != SIG_DFL) | |
| 70 | signal(i, h); | |
| 71 | sighandlers[i] = h; | |
| 72 | } | |
| 73 | } |