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[khatus.git] / x5 / khatus.c
1
2 #include <fcntl.h>
3 #include <unistd.h>
4 #include <sys/select.h>
5 #include <sys/stat.h>
6
7 #include <assert.h>
8 #include <ctype.h>
9 #include <errno.h>
10 #include <stdio.h>
11 #include <stdlib.h>
12 #include <string.h>
13
14 #define debug(args...) {fprintf(stderr, "[debug] " args);}
15 #define info( args...) {fprintf(stderr, "[info] " args);}
16 #define error(args...) {fprintf(stderr, "[error] " args);}
17 #define fatal(args...) {fprintf(stderr, "[fatal] " args); exit(EXIT_FAILURE);}
18 #define usage(args...) {print_usage(); fatal("[usage] " args);}
19
20 char *argv0;
21
22 /* TODO: Convert file list to file array. */
23 typedef struct File File;
24 struct File {
25 char *name;
26 int fd;
27 int width;
28 int last_read;
29 int ttl;
30 int pos; /* Position on the output buffer. */
31 File *next;
32 };
33
34 typedef struct Config Config;
35 struct Config {
36 int interval;
37 char * separator;
38 File * files;
39 int file_count;
40 int total_width;
41 } defaults = {
42 .interval = 1,
43 .separator = "|",
44 .files = NULL,
45 .file_count = 0,
46 .total_width = 0,
47 };
48
49 void
50 file_print_one(File *f)
51 {
52 debug(
53 "File "
54 "{"
55 " name = %s,"
56 " fd = %d,"
57 " width = %d,"
58 " last_read = %d,"
59 " ttl = %d,"
60 " pos = %d,"
61 " next = %p,"
62 " }\n",
63 f->name,
64 f->fd,
65 f->width,
66 f->last_read,
67 f->ttl,
68 f->pos,
69 f->next
70 );
71 }
72
73 void
74 file_print_all(File *head)
75 {
76 for (File *f = head; f; f = f->next) {
77 file_print_one(f);
78 }
79 }
80
81 void
82 config_print(Config *c)
83 {
84 debug(
85 "Config "
86 "{"
87 " interval = %d,"
88 " separator = %s,"
89 " file_count = %d,"
90 " total_width = %d,"
91 " files = ..."
92 " }\n",
93 c->interval,
94 c->separator,
95 c->file_count,
96 c->total_width
97 );
98 file_print_all(c->files);
99 }
100
101 int
102 is_pos_num(char *s)
103 {
104 while (*s != '\0')
105 if (!isdigit(*(s++)))
106 return 0;
107 return 1;
108 }
109
110 void
111 print_usage()
112 {
113 assert(argv0);
114 fprintf(
115 stderr,
116 "\n"
117 "Usage: %s [OPTION ...] SPEC [SPEC ...]\n"
118 "\n"
119 " SPEC = FILE_PATH DATA_WIDTH DATA_TTL\n"
120 " FILE_PATH = string\n"
121 " DATA_WIDTH = int (* (positive) number of characters *)\n"
122 " DATA_TTL = int (* (positive) number of seconds *)\n"
123 " OPTION = -i INTERVAL\n"
124 " | -s SEPARATOR\n"
125 " SEPARATOR = string\n"
126 " INTERVAL = int (* (positive) number of seconds *)\n"
127 "\n",
128 argv0
129 );
130 fprintf(
131 stderr,
132 "Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n"
133 "\n",
134 argv0
135 );
136 }
137
138 void opts_parse_any(Config *, int, char *[], int); /* For mutually-recursive calls. */
139
140 void
141 parse_opts_opt_i(Config *cfg, int argc, char *argv[], int i)
142 {
143 if (i < argc) {
144 char *param = argv[i++];
145
146 if (is_pos_num(param)) {
147 cfg->interval = atoi(param);
148 opts_parse_any(cfg, argc, argv, i);
149 } else {
150 usage("Option -i parameter is invalid: \"%s\"\n", param);
151 }
152 } else {
153 usage("Option -i parameter is missing.\n");
154 }
155 }
156
157 void
158 parse_opts_opt_s(Config *cfg, int argc, char *argv[], int i)
159 {
160 if (i < argc) {
161 cfg->separator = calloc((strlen(argv[i]) + 1), sizeof(char));
162 strcpy(cfg->separator, argv[i]);
163 opts_parse_any(cfg, argc, argv, ++i);
164 } else {
165 usage("Option -s parameter is missing.\n");
166 }
167 }
168
169 void
170 parse_opts_opt(Config *cfg, int argc, char *argv[], int i)
171 {
172 switch (argv[i][1]) {
173 case 'i': parse_opts_opt_i(cfg, argc, argv, ++i); break; /* TODO: Generic set_int */
174 case 's': parse_opts_opt_s(cfg, argc, argv, ++i); break; /* TODO: Generic set_str */
175 default : usage("Option \"%s\" is invalid\n", argv[i]);
176 }
177 }
178
179 void
180 parse_opts_spec(Config *cfg, int argc, char *argv[], int i)
181 {
182 if ((i + 3) > argc)
183 usage("[spec] Parameter(s) missing for file \"%s\".\n", argv[i]);
184
185 char *n = argv[i++];
186 char *w = argv[i++];
187 char *t = argv[i++];
188
189 if (!is_pos_num(w))
190 usage("[spec] Invalid width: \"%s\", for file \"%s\"\n", w, n);
191 if (!is_pos_num(t))
192 usage("[spec] Invalid TTL: \"%s\", for file \"%s\"\n", t, n);
193 File *f = calloc(1, sizeof(struct File));
194 if (f) {
195 f->name = n;
196 f->fd = -1;
197 f->width = atoi(w);
198 f->ttl = atoi(t);
199 f->last_read = 0;
200 f->pos = cfg->total_width;
201 f->next = cfg->files;
202
203 cfg->files = f;
204 cfg->total_width += f->width;
205 cfg->file_count++;
206 } else {
207 fatal("[memory] Allocation failure.");
208 }
209 opts_parse_any(cfg, argc, argv, i);
210 }
211
212 void
213 opts_parse_any(Config *cfg, int argc, char *argv[], int i)
214 {
215 if (i < argc) {
216 switch (argv[i][0]) {
217 case '-': parse_opts_opt(cfg, argc, argv, i); break;
218 default : parse_opts_spec(cfg, argc, argv, i);
219 }
220 }
221 }
222
223 void
224 opts_parse(Config *cfg, int argc, char *argv[], int i)
225 {
226 opts_parse_any(cfg, argc, argv, 1);
227
228 File *last = cfg->files;
229 cfg->files = NULL;
230 for (File *f = last; f; ) {
231 File *next = f->next;
232 f->next = cfg->files;
233 cfg->files = f;
234 f = next;
235 }
236 }
237
238 void
239 read_one(File *f, char *buf)
240 {
241 ssize_t current;
242 ssize_t total;
243 char *b;
244 char c;
245
246 current = 0;
247 total = 0;
248 c = '\0';
249 b = buf + f->pos;
250 memset(b, ' ', f->width);
251 while ((current = read(f->fd, &c, 1)) && c != '\n' && c != '\0' && total++ < f->width)
252 *b++ = c;
253 if (current == -1)
254 error("Failed to read: \"%s\". Error: %s\n", f->name, strerror(errno));
255 /* TODO Record timestamp read */
256 close(f->fd);
257 f->fd = -1;
258 }
259
260 void
261 read_all(Config *cfg, char *buf)
262 {
263 fd_set fds;
264 int maxfd;
265 int ready;
266 struct stat st;
267
268 FD_ZERO(&fds);
269
270 /* TODO: Check TTL */
271 for (File *f = cfg->files; f; f = f->next) {
272 /* TODO: Create the FIFO if it doesn't already exist. */
273 if (lstat(f->name, &st) < 0)
274 fatal("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
275 if (!(st.st_mode & S_IFIFO))
276 fatal("\"%s\" is not a FIFO\n", f->name);
277 debug("opening: %s\n", f->name);
278 if (f->fd < 0)
279 f->fd = open(f->name, O_RDONLY | O_NONBLOCK);
280 if (f->fd == -1)
281 /* TODO: Consider backing off retries for failed files. */
282 fatal("Failed to open \"%s\"\n", f->name);
283 if (f->fd > maxfd)
284 maxfd = f->fd;
285 FD_SET(f->fd, &fds);
286 }
287 debug("selecting...\n");
288 ready = select(maxfd + 1, &fds, NULL, NULL, NULL);
289 debug("ready: %d\n", ready);
290 assert(ready != 0);
291 if (ready < 0)
292 fatal("%s", strerror(errno));
293 for (File *f = cfg->files; f; f = f->next) {
294 if (FD_ISSET(f->fd, &fds)) {
295 debug("reading: %s\n", f->name);
296 read_one(f, buf);
297 }
298 }
299 }
300
301 int
302 main(int argc, char *argv[])
303 {
304 int width;
305 int nfiles = 0;
306 int seplen;
307 int prefix = 0;
308 char *buf;
309 Config *cfg = &defaults;
310
311 argv0 = argv[0];
312
313 opts_parse(cfg, argc, argv, 1);
314 debug("argv0 = %s\n", argv0);
315 config_print(cfg);
316 if (cfg->files == NULL)
317 usage("No file specs were given!\n");
318
319 width = cfg->total_width;
320 seplen = strlen(cfg->separator);
321
322 /* 1st pass to make space for separators */
323 for (File *f = cfg->files; f; f = f->next) {
324 f->pos += prefix;
325 prefix += seplen;
326 nfiles++;
327 }
328 width += (seplen * (nfiles - 1));
329 buf = calloc(1, width + 1);
330 if (buf == NULL)
331 fatal("[memory] Failed to allocate buffer of %d bytes", width);
332 memset(buf, ' ', width);
333 buf[width] = '\0';
334 /* 2nd pass to set the separators */
335 for (File *f = cfg->files; f; f = f->next) {
336 if (f->pos) { /* Skip the first, left-most */
337 /* Copying only seplen ensures we omit the '\0' byte. */
338 strncpy(buf + (f->pos - seplen), cfg->separator, seplen);
339 }
340 }
341
342 printf("%s\n", buf);
343 /* TODO: nanosleep and nano time diff */
344 for (;;) {
345 /* TODO: Check TTL and maybe blank-out */
346 /* TODO: How to trigger TTL check? On select? Alarm signal? */
347 /* TODO: Option to set X root window title or print */
348 read_all(cfg, buf);
349 printf("%s\n", buf);
350 }
351 }
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