Commit | Line | Data |
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fbfed6f0 JB |
1 | /* timer.c --- daemon to provide a tagged interval timer service |
2 | ||
3 | This little daemon runs forever waiting for signals. SIGIO (or | |
4 | SIGUSR1) causes it to read an event spec from stdin; that is, a | |
5 | date followed by colon followed by an event label. SIGALRM causes | |
6 | it to check its queue for events attached to the current second; if | |
7 | one is found, its label is written to stdout. SIGTERM causes it to | |
8 | terminate, printing a list of pending events. | |
9 | ||
10 | This program is intended to be used with the lisp package called | |
11 | timer.el. It was written anonymously in 1990. This version was | |
ee6b9d19 | 12 | documented and rewritten for portability by esr@snark.thyrsus.com, |
fbfed6f0 JB |
13 | Aug 7 1992. */ |
14 | ||
5cc564a6 | 15 | #include <stdio.h> |
16 | #include <signal.h> | |
17 | #include <fcntl.h> /* FASYNC */ | |
5cc564a6 | 18 | #include <sys/types.h> /* time_t */ |
19 | ||
18160b98 | 20 | #include <../src/config.h> |
9e2b097b JB |
21 | #ifdef USG |
22 | #undef SIGIO | |
23 | #define SIGIO SIGUSR1 | |
24 | #endif | |
25 | ||
2c029353 RS |
26 | #ifdef LINUX |
27 | /* Perhaps this is correct unconditionally. */ | |
28 | #undef signal | |
29 | #endif | |
30 | ||
31 | ||
5cc564a6 | 32 | extern int errno; |
fbfed6f0 JB |
33 | extern char *sys_errlist[], *malloc (); |
34 | extern time_t time (); | |
5cc564a6 | 35 | |
9e2b097b JB |
36 | /* |
37 | * The field separator for input. This character shouldn't be legal in a date, | |
38 | * and should be printable so event strings are readable by people. Was | |
39 | * originally ';', then got changed to bogus `\001'. | |
40 | */ | |
41 | #define FS '@' | |
42 | ||
43 | struct event | |
fbfed6f0 | 44 | { |
9e2b097b JB |
45 | char *token; |
46 | time_t reply_at; | |
fbfed6f0 JB |
47 | }; |
48 | int events_size; /* How many slots have we allocated? */ | |
49 | int num_events; /* How many are actually scheduled? */ | |
50 | struct event *events; /* events[0 .. num_events-1] are the | |
51 | valid events. */ | |
5cc564a6 | 52 | |
5cc564a6 | 53 | char *pname; /* programme name for error messages */ |
54 | ||
eb8c3be9 | 55 | /* Accepts a string of two fields separated by FS. |
ad2e78fb | 56 | First field is string for get_date, saying when to wake-up. |
fbfed6f0 JB |
57 | Second field is a token to identify the request. */ |
58 | void | |
59 | schedule (str) | |
60 | char *str; | |
5cc564a6 | 61 | { |
ad2e78fb | 62 | extern time_t get_date (); |
fbfed6f0 JB |
63 | extern char *strcpy (); |
64 | time_t now; | |
65 | register char *p; | |
66 | static struct event *ep; | |
67 | ||
68 | /* check entry format */ | |
69 | for (p = str; *p && *p != FS; p++) | |
70 | continue; | |
71 | if (!*p) | |
9e2b097b | 72 | { |
c193197b | 73 | fprintf (stderr, "%s: bad input format: %s\n", pname, str); |
fbfed6f0 | 74 | return; |
9e2b097b | 75 | } |
fbfed6f0 | 76 | *p++ = 0; |
5cc564a6 | 77 | |
fbfed6f0 JB |
78 | /* allocate an event slot */ |
79 | ep = events + num_events; | |
80 | ||
81 | /* If the event array is full, stretch it. After stretching, we know | |
82 | that ep will be pointing to an available event spot. */ | |
83 | if (ep == events + events_size) | |
9e2b097b | 84 | { |
fbfed6f0 | 85 | int old_size = events_size; |
9e2b097b | 86 | |
fbfed6f0 JB |
87 | events_size *= 2; |
88 | events = ((struct event *) | |
89 | realloc (events, events_size * sizeof (struct event))); | |
90 | if (! events) | |
91 | { | |
92 | fprintf (stderr, "%s: virtual memory exhausted.\n", pname); | |
93 | ||
94 | /* Should timer exit now? Well, we've still got other | |
95 | events in the queue, and more memory might become | |
96 | available in the future, so we'll just toss this event. | |
97 | This will screw up whoever scheduled the event, but | |
98 | maybe someone else will survive. */ | |
99 | return; | |
100 | } | |
101 | ||
102 | while (old_size < events_size) | |
103 | events[old_size++].token = NULL; | |
104 | } | |
105 | ||
106 | /* Don't allow users to schedule events in past time. */ | |
107 | ep->reply_at = get_date (str, NULL); | |
108 | if (ep->reply_at - time (&now) < 0) | |
109 | { | |
c193197b | 110 | fprintf (stderr, "%s: bad time spec: %s%c%s\n", pname, str, FS, p); |
fbfed6f0 JB |
111 | return; |
112 | } | |
113 | ||
114 | /* save the event description */ | |
115 | ep->token = (char *) malloc ((unsigned) strlen (p) + 1); | |
116 | if (! ep->token) | |
117 | { | |
c193197b | 118 | fprintf (stderr, "%s: malloc %s: %s%c%s\n", |
fbfed6f0 JB |
119 | pname, sys_errlist[errno], str, FS, p); |
120 | return; | |
9e2b097b | 121 | } |
fbfed6f0 JB |
122 | |
123 | strcpy (ep->token, p); | |
124 | num_events++; | |
5cc564a6 | 125 | } |
126 | ||
127 | void | |
fbfed6f0 | 128 | notify () |
5cc564a6 | 129 | { |
ca5b61ea | 130 | time_t now, tdiff, waitfor = -1; |
fbfed6f0 JB |
131 | register struct event *ep; |
132 | ||
ee6b9d19 ER |
133 | /* If an alarm timer runs out while this function is executing, |
134 | it could get called recursively. This would be bad, because | |
135 | it's not re-entrant. So we must try to suspend the signal. */ | |
9b528380 | 136 | #if 0 /* This function isn't right for BSD. Fix it later. */ |
ee6b9d19 ER |
137 | sighold(SIGIO); |
138 | #endif | |
139 | ||
fbfed6f0 | 140 | now = time ((time_t *) NULL); |
9e2b097b | 141 | |
fbfed6f0 JB |
142 | for (ep = events; ep < events + num_events; ep++) |
143 | /* Are any events ready to fire? */ | |
144 | if (ep->reply_at <= now) | |
145 | { | |
146 | fputs (ep->token, stdout); | |
07941899 | 147 | putc ('\n', stdout); |
507876f3 | 148 | fflush (stdout); |
fbfed6f0 | 149 | free (ep->token); |
9e2b097b | 150 | |
fbfed6f0 JB |
151 | /* We now have a hole in the event array; fill it with the last |
152 | event. */ | |
ee6b9d19 ER |
153 | ep->token = events[num_events - 1].token; |
154 | ep->reply_at = events[num_events - 1].reply_at; | |
fbfed6f0 JB |
155 | num_events--; |
156 | ||
157 | /* We ought to scan this event again. */ | |
158 | ep--; | |
159 | } | |
160 | else | |
161 | { | |
162 | /* next timeout should be the soonest of any remaining */ | |
163 | if ((tdiff = ep->reply_at - now) < waitfor || waitfor < 0) | |
164 | waitfor = (long)tdiff; | |
165 | } | |
166 | ||
167 | /* If there are no more events, we needn't bother setting an alarm. */ | |
168 | if (num_events > 0) | |
169 | alarm (waitfor); | |
ee6b9d19 | 170 | |
9b528380 | 171 | #if 0 /* This function isn't right for BSD. */ |
ee6b9d19 ER |
172 | sigrelse(SIGIO); |
173 | #endif | |
fbfed6f0 JB |
174 | } |
175 | ||
176 | void | |
177 | getevent () | |
178 | { | |
179 | int i; | |
180 | char *buf; | |
181 | int buf_size; | |
182 | ||
183 | /* In principle the itimer should be disabled on entry to this | |
184 | function, but it really doesn't make any important difference | |
185 | if it isn't. */ | |
186 | ||
187 | buf_size = 80; | |
188 | buf = (char *) malloc (buf_size); | |
189 | ||
190 | /* Read a line from standard input, expanding buf if it is too short | |
191 | to hold the line. */ | |
192 | for (i = 0; ; i++) | |
193 | { | |
194 | int c; | |
195 | ||
196 | if (i >= buf_size) | |
9e2b097b | 197 | { |
fbfed6f0 JB |
198 | buf_size *= 2; |
199 | buf = (char *) realloc (buf, buf_size); | |
200 | ||
201 | /* If we're out of memory, toss this event. */ | |
202 | do | |
9e2b097b | 203 | { |
fbfed6f0 | 204 | c = getchar (); |
9e2b097b | 205 | } |
fbfed6f0 JB |
206 | while (c != '\n' && c != EOF); |
207 | ||
208 | return; | |
9e2b097b JB |
209 | } |
210 | ||
fbfed6f0 | 211 | c = getchar (); |
5cc564a6 | 212 | |
fbfed6f0 JB |
213 | if (c == EOF) |
214 | exit (0); | |
9e2b097b | 215 | |
fbfed6f0 JB |
216 | if (c == '\n') |
217 | { | |
218 | buf[i] = '\0'; | |
219 | break; | |
220 | } | |
9e2b097b | 221 | |
fbfed6f0 JB |
222 | buf[i] = c; |
223 | } | |
9e2b097b | 224 | |
fbfed6f0 JB |
225 | /* Register the event. */ |
226 | schedule (buf); | |
227 | free (buf); | |
5cc564a6 | 228 | |
fbfed6f0 JB |
229 | /* Who knows what this interrupted, or if it said "now"? */ |
230 | notify (); | |
9e2b097b JB |
231 | } |
232 | ||
b1839491 | 233 | SIGTYPE |
fbfed6f0 JB |
234 | sigcatch (sig) |
235 | int sig; | |
9e2b097b | 236 | /* dispatch on incoming signal, then restore it */ |
5cc564a6 | 237 | { |
fbfed6f0 | 238 | struct event *ep; |
9e2b097b | 239 | |
fbfed6f0 | 240 | switch (sig) |
9e2b097b JB |
241 | { |
242 | case SIGALRM: | |
fbfed6f0 JB |
243 | notify (); |
244 | break; | |
9e2b097b | 245 | case SIGIO: |
fbfed6f0 JB |
246 | getevent (); |
247 | break; | |
9e2b097b | 248 | case SIGTERM: |
fbfed6f0 JB |
249 | fprintf (stderr, "Events still queued:\n"); |
250 | for (ep = events; ep < events + num_events; ep++) | |
c193197b | 251 | fprintf (stderr, "%d = %ld @ %s\n", |
fbfed6f0 JB |
252 | ep - events, ep->reply_at, ep->token); |
253 | exit (0); | |
254 | break; | |
9e2b097b JB |
255 | } |
256 | ||
fbfed6f0 JB |
257 | /* required on older UNIXes; harmless on newer ones */ |
258 | signal (sig, sigcatch); | |
5cc564a6 | 259 | } |
9e2b097b | 260 | |
5cc564a6 | 261 | /*ARGSUSED*/ |
262 | int | |
fbfed6f0 | 263 | main (argc, argv) |
5cc564a6 | 264 | int argc; |
265 | char **argv; | |
5cc564a6 | 266 | { |
fbfed6f0 JB |
267 | for (pname = argv[0] + strlen (argv[0]); |
268 | *pname != '/' && pname != argv[0]; | |
5cc564a6 | 269 | pname--); |
fbfed6f0 JB |
270 | if (*pname == '/') |
271 | pname++; | |
272 | ||
273 | events_size = 16; | |
274 | events = ((struct event *) malloc (events_size * sizeof (*events))); | |
275 | num_events = 0; | |
5cc564a6 | 276 | |
fbfed6f0 JB |
277 | signal (SIGIO, sigcatch); |
278 | signal (SIGALRM, sigcatch); | |
279 | signal (SIGTERM, sigcatch); | |
9e2b097b JB |
280 | |
281 | #ifndef USG | |
b1839491 JB |
282 | if (fcntl (0, F_SETOWN, getpid ()) == -1) |
283 | { | |
284 | fprintf (stderr, "%s: can't set ownership of stdin\n", pname); | |
285 | fprintf (stderr, "%s\n", sys_errlist[errno]); | |
286 | exit (1); | |
287 | } | |
288 | if (fcntl (0, F_SETFL, fcntl (0, F_GETFL, 0) | FASYNC) == -1) | |
289 | { | |
290 | fprintf (stderr, "%s: can't request asynchronous I/O on stdin\n", pname); | |
291 | fprintf (stderr, "%s\n", sys_errlist[errno]); | |
292 | exit (1); | |
293 | } | |
9e2b097b | 294 | #endif /* USG */ |
5cc564a6 | 295 | |
4d099053 RS |
296 | /* In case Emacs sent some input before we set up |
297 | the handling of SIGIO, read it now. */ | |
298 | kill (0, SIGIO); | |
299 | ||
ee6b9d19 | 300 | for (;;) |
4d099053 | 301 | pause (); |
5cc564a6 | 302 | } |
9e2b097b JB |
303 | |
304 | /* timer.c ends here */ |