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77c76070 SK |
1 | #include <fcntl.h> |
2 | #include <unistd.h> | |
3 | #include <sys/select.h> | |
4d66492f | 4 | |
9b5ebc12 SK |
5 | #include <assert.h> |
6 | #include <ctype.h> | |
77c76070 | 7 | #include <errno.h> |
9b5ebc12 SK |
8 | #include <stdio.h> |
9 | #include <stdlib.h> | |
10 | #include <string.h> | |
11 | ||
4d66492f SK |
12 | #define debug(args...) {fprintf(stderr, "[debug] " args);} |
13 | #define info( args...) {fprintf(stderr, "[info] " args);} | |
14 | #define error(args...) {fprintf(stderr, "[error] " args);} | |
15 | #define fatal(args...) {fprintf(stderr, "[fatal] " args); exit(EXIT_FAILURE);} | |
16 | #define usage(args...) {print_usage(); fatal("[usage] " args);} | |
9b5ebc12 | 17 | |
4d66492f | 18 | char *argv0; |
9b5ebc12 | 19 | |
4d66492f SK |
20 | typedef struct File File; |
21 | struct File { | |
22 | char *name; | |
23 | int fd; | |
9b5ebc12 | 24 | int width; |
4d66492f | 25 | int last_read; |
9b5ebc12 | 26 | int ttl; |
4d66492f SK |
27 | int pos; /* Position on the output buffer. */ |
28 | File *next; | |
9b5ebc12 SK |
29 | }; |
30 | ||
4d66492f SK |
31 | typedef struct Config Config; |
32 | struct Config { | |
9b5ebc12 | 33 | int interval; |
4d66492f | 34 | char * separator; |
4d66492f SK |
35 | File * files; |
36 | int file_count; | |
37 | int total_width; | |
38 | } defaults = { | |
39 | .interval = 1, | |
40 | .separator = "|", | |
4d66492f SK |
41 | .files = NULL, |
42 | .file_count = 0, | |
43 | .total_width = 0, | |
9b5ebc12 SK |
44 | }; |
45 | ||
77c76070 SK |
46 | void |
47 | file_print_one(File *f) | |
48 | { | |
49 | debug( | |
50 | "File " | |
51 | "{" | |
52 | " name = %s," | |
53 | " fd = %d," | |
54 | " width = %d," | |
55 | " last_read = %d," | |
56 | " ttl = %d," | |
57 | " pos = %d," | |
58 | " next = %p," | |
59 | " }\n", | |
60 | f->name, | |
61 | f->fd, | |
62 | f->width, | |
63 | f->last_read, | |
64 | f->ttl, | |
65 | f->pos, | |
66 | f->next | |
67 | ); | |
68 | } | |
69 | ||
70 | void | |
71 | file_print_all(File *head) | |
72 | { | |
73 | for (File *f = head; f; f = f->next) { | |
74 | file_print_one(f); | |
75 | } | |
76 | } | |
77 | ||
78 | void | |
79 | config_print(Config *c) | |
80 | { | |
81 | debug( | |
82 | "Config " | |
83 | "{" | |
84 | " interval = %d," | |
85 | " separator = %s," | |
86 | " file_count = %d," | |
87 | " total_width = %d," | |
88 | " files = ..." | |
89 | " }\n", | |
90 | c->interval, | |
91 | c->separator, | |
92 | c->file_count, | |
93 | c->total_width | |
94 | ); | |
95 | file_print_all(c->files); | |
96 | } | |
9b5ebc12 SK |
97 | |
98 | int | |
99 | is_pos_num(char *s) | |
100 | { | |
101 | while (*s != '\0') | |
102 | if (!isdigit(*(s++))) | |
103 | return 0; | |
104 | return 1; | |
105 | } | |
106 | ||
107 | void | |
108 | print_usage() | |
109 | { | |
4d66492f | 110 | assert(argv0); |
9b5ebc12 SK |
111 | fprintf( |
112 | stderr, | |
113 | "\n" | |
4d66492f | 114 | "Usage: %s [OPTION ...] SPEC [SPEC ...]\n" |
9b5ebc12 | 115 | "\n" |
4d66492f SK |
116 | " SPEC = FILE_PATH DATA_WIDTH DATA_TTL\n" |
117 | " FILE_PATH = string\n" | |
118 | " DATA_WIDTH = int (* (positive) number of characters *)\n" | |
119 | " DATA_TTL = int (* (positive) number of seconds *)\n" | |
120 | " OPTION = -i INTERVAL\n" | |
121 | " | -s SEPARATOR\n" | |
122 | " SEPARATOR = string\n" | |
123 | " INTERVAL = int (* (positive) number of seconds *)\n" | |
9b5ebc12 | 124 | "\n", |
4d66492f | 125 | argv0 |
9b5ebc12 SK |
126 | ); |
127 | fprintf( | |
128 | stderr, | |
129 | "Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n" | |
130 | "\n", | |
4d66492f | 131 | argv0 |
9b5ebc12 SK |
132 | ); |
133 | } | |
134 | ||
4d66492f | 135 | void opts_parse_any(Config *, int, char *[], int); /* For mutually-recursive calls. */ |
9b5ebc12 SK |
136 | |
137 | void | |
4d66492f | 138 | parse_opts_opt_i(Config *cfg, int argc, char *argv[], int i) |
9b5ebc12 SK |
139 | { |
140 | if (i < argc) { | |
141 | char *param = argv[i++]; | |
142 | ||
143 | if (is_pos_num(param)) { | |
4d66492f SK |
144 | cfg->interval = atoi(param); |
145 | opts_parse_any(cfg, argc, argv, i); | |
9b5ebc12 SK |
146 | } else { |
147 | usage("Option -i parameter is invalid: \"%s\"\n", param); | |
148 | } | |
149 | } else { | |
150 | usage("Option -i parameter is missing.\n"); | |
151 | } | |
152 | } | |
153 | ||
154 | void | |
4d66492f SK |
155 | parse_opts_opt_s(Config *cfg, int argc, char *argv[], int i) |
156 | { | |
157 | if (i < argc) { | |
3c836bfd | 158 | cfg->separator = calloc((strlen(argv[i]) + 1), sizeof(char)); |
4d66492f SK |
159 | strcpy(cfg->separator, argv[i]); |
160 | opts_parse_any(cfg, argc, argv, ++i); | |
161 | } else { | |
162 | usage("Option -s parameter is missing.\n"); | |
163 | } | |
164 | } | |
165 | ||
4d66492f SK |
166 | void |
167 | parse_opts_opt(Config *cfg, int argc, char *argv[], int i) | |
9b5ebc12 SK |
168 | { |
169 | switch (argv[i][1]) { | |
4d66492f SK |
170 | case 'i': parse_opts_opt_i(cfg, argc, argv, ++i); break; /* TODO: Generic set_int */ |
171 | case 's': parse_opts_opt_s(cfg, argc, argv, ++i); break; /* TODO: Generic set_str */ | |
9b5ebc12 SK |
172 | default : usage("Option \"%s\" is invalid\n", argv[i]); |
173 | } | |
174 | } | |
175 | ||
176 | void | |
4d66492f | 177 | parse_opts_spec(Config *cfg, int argc, char *argv[], int i) |
9b5ebc12 SK |
178 | { |
179 | if ((i + 3) > argc) | |
180 | usage("[spec] Parameter(s) missing for file \"%s\".\n", argv[i]); | |
181 | ||
182 | char *n = argv[i++]; | |
183 | char *w = argv[i++]; | |
184 | char *t = argv[i++]; | |
185 | ||
186 | if (!is_pos_num(w)) | |
187 | usage("[spec] Invalid width: \"%s\", for file \"%s\"\n", w, n); | |
188 | if (!is_pos_num(t)) | |
189 | usage("[spec] Invalid TTL: \"%s\", for file \"%s\"\n", t, n); | |
3c836bfd | 190 | File *f = calloc(1, sizeof(struct File)); |
9b5ebc12 | 191 | if (f) { |
4d66492f SK |
192 | f->name = n; |
193 | f->fd = -1; | |
194 | f->width = atoi(w); | |
195 | f->ttl = atoi(t); | |
196 | f->last_read = 0; | |
197 | f->pos = cfg->total_width; | |
198 | f->next = cfg->files; | |
199 | ||
200 | cfg->files = f; | |
201 | cfg->total_width += f->width; | |
202 | cfg->file_count++; | |
9b5ebc12 | 203 | } else { |
4d66492f | 204 | fatal("[memory] Allocation failure."); |
9b5ebc12 | 205 | } |
4d66492f | 206 | opts_parse_any(cfg, argc, argv, i); |
9b5ebc12 SK |
207 | } |
208 | ||
209 | void | |
4d66492f | 210 | opts_parse_any(Config *cfg, int argc, char *argv[], int i) |
9b5ebc12 SK |
211 | { |
212 | if (i < argc) { | |
213 | switch (argv[i][0]) { | |
4d66492f SK |
214 | case '-': parse_opts_opt(cfg, argc, argv, i); break; |
215 | default : parse_opts_spec(cfg, argc, argv, i); | |
216 | } | |
217 | } | |
218 | } | |
219 | ||
220 | void | |
221 | opts_parse(Config *cfg, int argc, char *argv[], int i) | |
222 | { | |
223 | opts_parse_any(cfg, argc, argv, 1); | |
224 | ||
225 | File *last = cfg->files; | |
226 | cfg->files = NULL; | |
227 | for (File *f = last; f; ) { | |
228 | File *next = f->next; | |
229 | f->next = cfg->files; | |
230 | cfg->files = f; | |
231 | f = next; | |
232 | } | |
233 | } | |
234 | ||
77c76070 SK |
235 | void |
236 | read_one(File *f, char *buf) | |
237 | { | |
238 | ssize_t n; | |
239 | char *b; | |
240 | ||
241 | b = buf + f->pos; | |
242 | memset(b, ' ', f->width); | |
243 | while ((n = read(f->fd, b, f->width)) > 0) { | |
244 | b += n; | |
245 | debug("read %zd from %s\n", n, f->name); | |
246 | } | |
247 | ||
248 | if (n > -1) { | |
249 | if (*(b - 1) == '\n') | |
250 | *(b - 1) = ' '; | |
251 | } else { | |
252 | error( | |
253 | "Failed to read: \"%s\". Error: %s\n", | |
254 | f->name, | |
255 | strerror(errno) | |
256 | ); | |
257 | } | |
258 | ||
259 | close(f->fd); | |
260 | f->fd = -1; | |
261 | } | |
262 | ||
4d66492f SK |
263 | void |
264 | read_all(Config *cfg, char *buf) | |
265 | { | |
77c76070 SK |
266 | fd_set fds; |
267 | int maxfd; | |
268 | int ready; | |
269 | ||
270 | FD_ZERO(&fds); | |
271 | ||
4d66492f SK |
272 | /* TODO: stat then check TTL */ |
273 | for (File *f = cfg->files; f; f = f->next) { | |
77c76070 | 274 | debug("opening: %s\n", f->name); |
4d66492f | 275 | if (f->fd < 0) |
77c76070 SK |
276 | f->fd = open(f->name, O_RDONLY | O_NONBLOCK); |
277 | if (f->fd == -1) | |
4d66492f SK |
278 | /* TODO: Consider backing off retries for failed files. */ |
279 | fatal("Failed to open \"%s\"\n", f->name); | |
77c76070 SK |
280 | if (f->fd > maxfd) |
281 | maxfd = f->fd; | |
282 | FD_SET(f->fd, &fds); | |
283 | } | |
284 | debug("selecting...\n"); | |
285 | ready = select(maxfd + 1, &fds, NULL, NULL, NULL); | |
286 | debug("ready: %d\n", ready); | |
287 | assert(ready != 0); | |
288 | if (ready < 0) | |
289 | fatal("%s", strerror(errno)); | |
290 | for (File *f = cfg->files; f; f = f->next) { | |
291 | if (FD_ISSET(f->fd, &fds)) { | |
292 | debug("reading: %s\n", f->name); | |
293 | read_one(f, buf); | |
9b5ebc12 SK |
294 | } |
295 | } | |
296 | } | |
297 | ||
298 | int | |
4d66492f | 299 | main(int argc, char *argv[]) |
9b5ebc12 | 300 | { |
4d66492f SK |
301 | int width; |
302 | int nfiles = 0; | |
303 | int seplen; | |
304 | int prefix = 0; | |
305 | char *buf; | |
306 | Config *cfg = &defaults; | |
307 | ||
308 | argv0 = argv[0]; | |
309 | ||
310 | opts_parse(cfg, argc, argv, 1); | |
311 | debug("argv0 = %s\n", argv0); | |
77c76070 | 312 | config_print(cfg); |
4d66492f | 313 | if (cfg->files == NULL) |
9b5ebc12 | 314 | usage("No file specs were given!\n"); |
4d66492f SK |
315 | |
316 | width = cfg->total_width; | |
317 | seplen = strlen(cfg->separator); | |
318 | ||
319 | /* 1st pass to make space for separators */ | |
320 | for (File *f = cfg->files; f; f = f->next) { | |
321 | f->pos += prefix; | |
322 | prefix += seplen; | |
323 | nfiles++; | |
324 | } | |
325 | width += (seplen * (nfiles - 1)); | |
3c836bfd | 326 | buf = calloc(1, width + 1); |
4d66492f SK |
327 | if (buf == NULL) |
328 | fatal("[memory] Failed to allocate buffer of %d bytes", width); | |
329 | memset(buf, ' ', width); | |
330 | buf[width] = '\0'; | |
331 | /* 2nd pass to set the separators */ | |
332 | for (File *f = cfg->files; f; f = f->next) { | |
333 | if (f->pos) { /* Skip the first, left-most */ | |
77c76070 SK |
334 | /* Copying only seplen ensures we omit the '\0' byte. */ |
335 | strncpy(buf + (f->pos - seplen), cfg->separator, seplen); | |
4d66492f SK |
336 | } |
337 | } | |
338 | ||
77c76070 | 339 | printf("%s\n", buf); |
4d66492f SK |
340 | /* TODO: nanosleep and nano time diff */ |
341 | for (;;) { | |
342 | read_all(cfg, buf); | |
343 | printf("%s\n", buf); | |
4d66492f | 344 | } |
9b5ebc12 | 345 | } |