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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 | |
12 | documented and rewritten for portability by esr@snark,thyrsus.com, | |
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 | ||
9e2b097b JB |
20 | #include "../src/config.h" |
21 | #ifdef USG | |
22 | #undef SIGIO | |
23 | #define SIGIO SIGUSR1 | |
24 | #endif | |
25 | ||
5cc564a6 | 26 | extern int errno; |
fbfed6f0 JB |
27 | extern char *sys_errlist[], *malloc (); |
28 | extern time_t time (); | |
5cc564a6 | 29 | |
9e2b097b JB |
30 | /* |
31 | * The field separator for input. This character shouldn't be legal in a date, | |
32 | * and should be printable so event strings are readable by people. Was | |
33 | * originally ';', then got changed to bogus `\001'. | |
34 | */ | |
35 | #define FS '@' | |
36 | ||
37 | struct event | |
fbfed6f0 | 38 | { |
9e2b097b JB |
39 | char *token; |
40 | time_t reply_at; | |
fbfed6f0 JB |
41 | }; |
42 | int events_size; /* How many slots have we allocated? */ | |
43 | int num_events; /* How many are actually scheduled? */ | |
44 | struct event *events; /* events[0 .. num_events-1] are the | |
45 | valid events. */ | |
5cc564a6 | 46 | |
5cc564a6 | 47 | char *pname; /* programme name for error messages */ |
48 | ||
9e2b097b | 49 | /* Accepts a string of two fields seperated by FS. |
fbfed6f0 JB |
50 | First field is string for getdate, saying when to wake-up. |
51 | Second field is a token to identify the request. */ | |
52 | void | |
53 | schedule (str) | |
54 | char *str; | |
5cc564a6 | 55 | { |
fbfed6f0 JB |
56 | extern time_t getdate (); |
57 | extern char *strcpy (); | |
58 | time_t now; | |
59 | register char *p; | |
60 | static struct event *ep; | |
61 | ||
62 | /* check entry format */ | |
63 | for (p = str; *p && *p != FS; p++) | |
64 | continue; | |
65 | if (!*p) | |
9e2b097b | 66 | { |
fbfed6f0 JB |
67 | fprintf (stderr, "%s: bad input format: %s", pname, str); |
68 | return; | |
9e2b097b | 69 | } |
fbfed6f0 | 70 | *p++ = 0; |
5cc564a6 | 71 | |
fbfed6f0 JB |
72 | /* allocate an event slot */ |
73 | ep = events + num_events; | |
74 | ||
75 | /* If the event array is full, stretch it. After stretching, we know | |
76 | that ep will be pointing to an available event spot. */ | |
77 | if (ep == events + events_size) | |
9e2b097b | 78 | { |
fbfed6f0 | 79 | int old_size = events_size; |
9e2b097b | 80 | |
fbfed6f0 JB |
81 | events_size *= 2; |
82 | events = ((struct event *) | |
83 | realloc (events, events_size * sizeof (struct event))); | |
84 | if (! events) | |
85 | { | |
86 | fprintf (stderr, "%s: virtual memory exhausted.\n", pname); | |
87 | ||
88 | /* Should timer exit now? Well, we've still got other | |
89 | events in the queue, and more memory might become | |
90 | available in the future, so we'll just toss this event. | |
91 | This will screw up whoever scheduled the event, but | |
92 | maybe someone else will survive. */ | |
93 | return; | |
94 | } | |
95 | ||
96 | while (old_size < events_size) | |
97 | events[old_size++].token = NULL; | |
98 | } | |
99 | ||
100 | /* Don't allow users to schedule events in past time. */ | |
101 | ep->reply_at = get_date (str, NULL); | |
102 | if (ep->reply_at - time (&now) < 0) | |
103 | { | |
104 | fprintf (stderr, "%s: bad time spec: %s%c%s", pname, str, FS, p); | |
105 | return; | |
106 | } | |
107 | ||
108 | /* save the event description */ | |
109 | ep->token = (char *) malloc ((unsigned) strlen (p) + 1); | |
110 | if (! ep->token) | |
111 | { | |
112 | fprintf (stderr, "%s: malloc %s: %s%c%s", | |
113 | pname, sys_errlist[errno], str, FS, p); | |
114 | return; | |
9e2b097b | 115 | } |
fbfed6f0 JB |
116 | |
117 | strcpy (ep->token, p); | |
118 | num_events++; | |
5cc564a6 | 119 | } |
120 | ||
121 | void | |
fbfed6f0 | 122 | notify () |
5cc564a6 | 123 | { |
fbfed6f0 JB |
124 | time_t now, tdiff, waitfor; |
125 | register struct event *ep; | |
126 | ||
127 | now = time ((time_t *) NULL); | |
9e2b097b | 128 | |
fbfed6f0 JB |
129 | for (ep = events; ep < events + num_events; ep++) |
130 | /* Are any events ready to fire? */ | |
131 | if (ep->reply_at <= now) | |
132 | { | |
133 | fputs (ep->token, stdout); | |
07941899 | 134 | putc ('\n', stdout); |
507876f3 | 135 | fflush (stdout); |
fbfed6f0 | 136 | free (ep->token); |
9e2b097b | 137 | |
fbfed6f0 JB |
138 | /* We now have a hole in the event array; fill it with the last |
139 | event. */ | |
140 | ep->token = events[num_events].token; | |
141 | ep->reply_at = events[num_events].reply_at; | |
142 | num_events--; | |
143 | ||
144 | /* We ought to scan this event again. */ | |
145 | ep--; | |
146 | } | |
147 | else | |
148 | { | |
149 | /* next timeout should be the soonest of any remaining */ | |
150 | if ((tdiff = ep->reply_at - now) < waitfor || waitfor < 0) | |
151 | waitfor = (long)tdiff; | |
152 | } | |
153 | ||
154 | /* If there are no more events, we needn't bother setting an alarm. */ | |
155 | if (num_events > 0) | |
156 | alarm (waitfor); | |
157 | } | |
158 | ||
159 | void | |
160 | getevent () | |
161 | { | |
162 | int i; | |
163 | char *buf; | |
164 | int buf_size; | |
165 | ||
166 | /* In principle the itimer should be disabled on entry to this | |
167 | function, but it really doesn't make any important difference | |
168 | if it isn't. */ | |
169 | ||
170 | buf_size = 80; | |
171 | buf = (char *) malloc (buf_size); | |
172 | ||
173 | /* Read a line from standard input, expanding buf if it is too short | |
174 | to hold the line. */ | |
175 | for (i = 0; ; i++) | |
176 | { | |
177 | int c; | |
178 | ||
179 | if (i >= buf_size) | |
9e2b097b | 180 | { |
fbfed6f0 JB |
181 | buf_size *= 2; |
182 | buf = (char *) realloc (buf, buf_size); | |
183 | ||
184 | /* If we're out of memory, toss this event. */ | |
185 | do | |
9e2b097b | 186 | { |
fbfed6f0 | 187 | c = getchar (); |
9e2b097b | 188 | } |
fbfed6f0 JB |
189 | while (c != '\n' && c != EOF); |
190 | ||
191 | return; | |
9e2b097b JB |
192 | } |
193 | ||
fbfed6f0 | 194 | c = getchar (); |
5cc564a6 | 195 | |
fbfed6f0 JB |
196 | if (c == EOF) |
197 | exit (0); | |
9e2b097b | 198 | |
fbfed6f0 JB |
199 | if (c == '\n') |
200 | { | |
201 | buf[i] = '\0'; | |
202 | break; | |
203 | } | |
9e2b097b | 204 | |
fbfed6f0 JB |
205 | buf[i] = c; |
206 | } | |
9e2b097b | 207 | |
fbfed6f0 JB |
208 | /* Register the event. */ |
209 | schedule (buf); | |
210 | free (buf); | |
5cc564a6 | 211 | |
fbfed6f0 JB |
212 | /* Who knows what this interrupted, or if it said "now"? */ |
213 | notify (); | |
9e2b097b JB |
214 | } |
215 | ||
216 | void | |
fbfed6f0 JB |
217 | sigcatch (sig) |
218 | int sig; | |
9e2b097b | 219 | /* dispatch on incoming signal, then restore it */ |
5cc564a6 | 220 | { |
fbfed6f0 | 221 | struct event *ep; |
9e2b097b | 222 | |
fbfed6f0 | 223 | switch (sig) |
9e2b097b JB |
224 | { |
225 | case SIGALRM: | |
fbfed6f0 JB |
226 | notify (); |
227 | break; | |
9e2b097b | 228 | case SIGIO: |
fbfed6f0 JB |
229 | getevent (); |
230 | break; | |
9e2b097b | 231 | case SIGTERM: |
fbfed6f0 JB |
232 | fprintf (stderr, "Events still queued:\n"); |
233 | for (ep = events; ep < events + num_events; ep++) | |
234 | fprintf (stderr, "%d = %ld @ %s", | |
235 | ep - events, ep->reply_at, ep->token); | |
236 | exit (0); | |
237 | break; | |
9e2b097b JB |
238 | } |
239 | ||
fbfed6f0 JB |
240 | /* required on older UNIXes; harmless on newer ones */ |
241 | signal (sig, sigcatch); | |
5cc564a6 | 242 | } |
9e2b097b | 243 | |
5cc564a6 | 244 | /*ARGSUSED*/ |
245 | int | |
fbfed6f0 | 246 | main (argc, argv) |
5cc564a6 | 247 | int argc; |
248 | char **argv; | |
5cc564a6 | 249 | { |
fbfed6f0 JB |
250 | for (pname = argv[0] + strlen (argv[0]); |
251 | *pname != '/' && pname != argv[0]; | |
5cc564a6 | 252 | pname--); |
fbfed6f0 JB |
253 | if (*pname == '/') |
254 | pname++; | |
255 | ||
256 | events_size = 16; | |
257 | events = ((struct event *) malloc (events_size * sizeof (*events))); | |
258 | num_events = 0; | |
5cc564a6 | 259 | |
fbfed6f0 JB |
260 | signal (SIGIO, sigcatch); |
261 | signal (SIGALRM, sigcatch); | |
262 | signal (SIGTERM, sigcatch); | |
9e2b097b JB |
263 | |
264 | #ifndef USG | |
fbfed6f0 | 265 | fcntl (0, F_SETFL, FASYNC); |
9e2b097b | 266 | #endif /* USG */ |
5cc564a6 | 267 | |
fbfed6f0 | 268 | while (1) pause (); |
5cc564a6 | 269 | } |
9e2b097b JB |
270 | |
271 | /* timer.c ends here */ |