src/udev/collect/collect.c

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * Collect variables across events.
   4  *
   5  * usage: collect [--add|--remove] <checkpoint> <id> <idlist>
   6  *
   7  * Adds ID <id> to the list governed by <checkpoint>.
   8  * <id> must be part of the ID list <idlist>.
   9  * If all IDs given by <idlist> are listed (ie collect has been
  10  * invoked for each ID in <idlist>) collect returns 0, the
  11  * number of missing IDs otherwise.
  12  * A negative number is returned on error.
  13  *
  14  * Copyright © 2007, Hannes Reinecke <hare@suse.de>
  15  *
  16  * This program is free software: you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation, either version 2 of the License, or
  19  * (at your option) any later version.
  20  */
  21
  22 #include <errno.h>
  23 #include <getopt.h>
  24 #include <stddef.h>
  25 #include <stdio.h>
  26
  27 #include "alloc-util.h"
  28 #include "libudev-private.h"
  29 #include "macro.h"
  30 #include "stdio-util.h"
  31 #include "string-util.h"
  32 #include "udev-util.h"
  33
  34 #define BUFSIZE 16
  35 #define UDEV_ALARM_TIMEOUT 180
  36
  37 enum collect_state {
  38         STATE_NONE,
  39         STATE_OLD,
  40         STATE_CONFIRMED,
  41 };
  42
  43 struct _mate {
  44         struct udev_list_node node;
  45         char *name;
  46         enum collect_state state;
  47 };
  48
  49 static struct udev_list_node bunch;
  50 static int debug;
  51
  52 /* This can increase dynamically */
  53 static size_t bufsize = BUFSIZE;
  54
  55 static inline struct _mate *node_to_mate(struct udev_list_node *node)
  56 {
  57         return container_of(node, struct _mate, node);
  58 }
  59
  60 _noreturn_ static void sig_alrm(int signo)
  61 {
  62         exit(4);
  63 }
  64
  65 static void usage(void)
  66 {
  67         printf("%s [options] <checkpoint> <id> <idlist>\n\n"
  68                "Collect variables across events.\n\n"
  69                "  -h --help        Print this message\n"
  70                "  -a --add         Add ID <id> to the list <idlist>\n"
  71                "  -r --remove      Remove ID <id> from the list <idlist>\n"
  72                "  -d --debug       Debug to stderr\n\n"
  73                "  Adds ID <id> to the list governed by <checkpoint>.\n"
  74                "  <id> must be part of the list <idlist>.\n"
  75                "  If all IDs given by <idlist> are listed (ie collect has been\n"
  76                "  invoked for each ID in <idlist>) collect returns 0, the\n"
  77                "  number of missing IDs otherwise.\n"
  78                "  On error a negative number is returned.\n\n"
  79                , program_invocation_short_name);
  80 }
  81
  82 /*
  83  * prepare
  84  *
  85  * Prepares the database file
  86  */
  87 static int prepare(char *dir, char *filename)
  88 {
  89         char buf[PATH_MAX];
  90         int r, fd;
  91
  92         r = mkdir(dir, 0700);
  93         if (r < 0 && errno != EEXIST)
  94                 return -errno;
  95
  96         snprintf(buf, sizeof buf, "%s/%s", dir, filename);
  97
  98         fd = open(buf, O_RDWR|O_CREAT|O_CLOEXEC, S_IRUSR|S_IWUSR);
  99         if (fd < 0)
 100                 fprintf(stderr, "Cannot open %s: %m\n", buf);
 101
 102         if (lockf(fd,F_TLOCK,0) < 0) {
 103                 if (debug)
 104                         fprintf(stderr, "Lock taken, wait for %d seconds\n", UDEV_ALARM_TIMEOUT);
 105                 if (IN_SET(errno, EAGAIN, EACCES)) {
 106                         alarm(UDEV_ALARM_TIMEOUT);
 107                         lockf(fd, F_LOCK, 0);
 108                         if (debug)
 109                                 fprintf(stderr, "Acquired lock on %s\n", buf);
 110                 } else {
 111                         if (debug)
 112                                 fprintf(stderr, "Could not get lock on %s: %m\n", buf);
 113                 }
 114         }
 115
 116         return fd;
 117 }
 118
 119 /*
 120  * Read checkpoint file
 121  *
 122  * Tricky reading this. We allocate a buffer twice as large
 123  * as we're going to read. Then we read into the upper half
 124  * of that buffer and start parsing.
 125  * Once we do _not_ find end-of-work terminator (whitespace
 126  * character) we move the upper half to the lower half,
 127  * adjust the read pointer and read the next bit.
 128  * Quite clever methinks :-)
 129  * I should become a programmer ...
 130  *
 131  * Yes, one could have used fgets() for this. But then we'd
 132  * have to use freopen etc which I found quite tedious.
 133  */
 134 static int checkout(int fd)
 135 {
 136         int len;
 137         _cleanup_free_ char *buf = NULL;
 138         char *ptr, *word = NULL;
 139         struct _mate *him;
 140
 141  restart:
 142         len = bufsize >> 1;
 143         buf = malloc(bufsize + 1);
 144         if (!buf)
 145                 return log_oom();
 146         memset(buf, ' ', bufsize);
 147         buf[bufsize] = '\0';
 148
 149         ptr = buf + len;
 150         while ((read(fd, buf + len, len)) > 0) {
 151                 while (ptr && *ptr) {
 152                         word = ptr;
 153                         ptr = strpbrk(word," \n\t\r");
 154                         if (!ptr && word < (buf + len)) {
 155                                 bufsize = bufsize << 1;
 156                                 if (debug)
 157                                         fprintf(stderr, "ID overflow, restarting with size %zu\n", bufsize);
 158                                 lseek(fd, 0, SEEK_SET);
 159                                 goto restart;
 160                         }
 161                         if (ptr) {
 162                                 *ptr = '\0';
 163                                 ptr++;
 164                                 if (isempty(word))
 165                                         continue;
 166
 167                                 if (debug)
 168                                         fprintf(stderr, "Found word %s\n", word);
 169                                 him = malloc(sizeof (struct _mate));
 170                                 if (!him)
 171                                         return log_oom();
 172                                 him->name = strdup(word);
 173                                 if (!him->name) {
 174                                         free(him);
 175                                         return log_oom();
 176                                 }
 177                                 him->state = STATE_OLD;
 178                                 udev_list_node_append(&him->node, &bunch);
 179                                 word = NULL;
 180                         }
 181                 }
 182                 memcpy(buf, buf + len, len);
 183                 memset(buf + len, ' ', len);
 184
 185                 if (!ptr)
 186                         ptr = word;
 187                 ptr -= len;
 188         }
 189
 190         return 0;
 191 }
 192
 193 /*
 194  * invite
 195  *
 196  * Adds a new ID 'us' to the internal list,
 197  * marks it as confirmed.
 198  */
 199 static void invite(char *us)
 200 {
 201         struct udev_list_node *him_node;
 202         struct _mate *who = NULL;
 203
 204         if (debug)
 205                 fprintf(stderr, "Adding ID '%s'\n", us);
 206
 207         udev_list_node_foreach(him_node, &bunch) {
 208                 struct _mate *him = node_to_mate(him_node);
 209
 210                 if (streq(him->name, us)) {
 211                         him->state = STATE_CONFIRMED;
 212                         who = him;
 213                 }
 214         }
 215         if (debug && !who)
 216                 fprintf(stderr, "ID '%s' not in database\n", us);
 217
 218 }
 219
 220 /*
 221  * reject
 222  *
 223  * Marks the ID 'us' as invalid,
 224  * causing it to be removed when the
 225  * list is written out.
 226  */
 227 static void reject(char *us)
 228 {
 229         struct udev_list_node *him_node;
 230         struct _mate *who = NULL;
 231
 232         if (debug)
 233                 fprintf(stderr, "Removing ID '%s'\n", us);
 234
 235         udev_list_node_foreach(him_node, &bunch) {
 236                 struct _mate *him = node_to_mate(him_node);
 237
 238                 if (streq(him->name, us)) {
 239                         him->state = STATE_NONE;
 240                         who = him;
 241                 }
 242         }
 243         if (debug && !who)
 244                 fprintf(stderr, "ID '%s' not in database\n", us);
 245 }
 246
 247 /*
 248  * kickout
 249  *
 250  * Remove all IDs in the internal list which are not part
 251  * of the list passed via the command line.
 252  */
 253 static void kickout(void)
 254 {
 255         struct udev_list_node *him_node;
 256         struct udev_list_node *tmp;
 257
 258         udev_list_node_foreach_safe(him_node, tmp, &bunch) {
 259                 struct _mate *him = node_to_mate(him_node);
 260
 261                 if (him->state == STATE_OLD) {
 262                         udev_list_node_remove(&him->node);
 263                         free(him->name);
 264                         free(him);
 265                 }
 266         }
 267 }
 268
 269 /*
 270  * missing
 271  *
 272  * Counts all missing IDs in the internal list.
 273  */
 274 static int missing(int fd)
 275 {
 276         char *buf;
 277         int ret = 0;
 278         struct udev_list_node *him_node;
 279
 280         buf = malloc(bufsize);
 281         if (!buf)
 282                 return log_oom();
 283
 284         udev_list_node_foreach(him_node, &bunch) {
 285                 struct _mate *him = node_to_mate(him_node);
 286
 287                 if (him->state == STATE_NONE) {
 288                         ret++;
 289                 } else {
 290                         while (strlen(him->name)+1 >= bufsize) {
 291                                 char *tmpbuf;
 292
 293                                 bufsize = bufsize << 1;
 294                                 tmpbuf = realloc(buf, bufsize);
 295                                 if (!tmpbuf) {
 296                                         free(buf);
 297                                         return log_oom();
 298                                 }
 299                                 buf = tmpbuf;
 300                         }
 301                         snprintf(buf, strlen(him->name)+2, "%s ", him->name);
 302                         if (write(fd, buf, strlen(buf)) < 0) {
 303                                 free(buf);
 304                                 return -1;
 305                         }
 306                 }
 307         }
 308
 309         free(buf);
 310         return ret;
 311 }
 312
 313 /*
 314  * everybody
 315  *
 316  * Prints out the status of the internal list.
 317  */
 318 static void everybody(void)
 319 {
 320         struct udev_list_node *him_node;
 321         const char *state = "";
 322
 323         udev_list_node_foreach(him_node, &bunch) {
 324                 struct _mate *him = node_to_mate(him_node);
 325
 326                 switch (him->state) {
 327                 case STATE_NONE:
 328                         state = "none";
 329                         break;
 330                 case STATE_OLD:
 331                         state = "old";
 332                         break;
 333                 case STATE_CONFIRMED:
 334                         state = "confirmed";
 335                         break;
 336                 }
 337                 fprintf(stderr, "ID: %s=%s\n", him->name, state);
 338         }
 339 }
 340
 341 int main(int argc, char **argv) {
 342         static const struct option options[] = {
 343                 { "add", no_argument, NULL, 'a' },
 344                 { "remove", no_argument, NULL, 'r' },
 345                 { "debug", no_argument, NULL, 'd' },
 346                 { "help", no_argument, NULL, 'h' },
 347                 {}
 348         };
 349         int argi;
 350         char *checkpoint, *us;
 351         int fd;
 352         int i;
 353         int ret = EXIT_SUCCESS;
 354         int prune = 0;
 355         char tmpdir[UTIL_PATH_SIZE];
 356
 357         log_set_target(LOG_TARGET_AUTO);
 358         udev_parse_config();
 359         log_parse_environment();
 360         log_open();
 361
 362         for (;;) {
 363                 int option;
 364
 365                 option = getopt_long(argc, argv, "ardh", options, NULL);
 366                 if (option == -1)
 367                         break;
 368
 369                 switch (option) {
 370                 case 'a':
 371                         prune = 0;
 372                         break;
 373                 case 'r':
 374                         prune = 1;
 375                         break;
 376                 case 'd':
 377                         debug = 1;
 378                         break;
 379                 case 'h':
 380                         usage();
 381                         return 0;
 382                 default:
 383                         return 1;
 384                 }
 385         }
 386
 387         argi = optind;
 388         if (argi + 2 > argc) {
 389                 printf("Missing parameter(s)\n");
 390                 return 1;
 391         }
 392         checkpoint = argv[argi++];
 393         us = argv[argi++];
 394
 395         if (signal(SIGALRM, sig_alrm) == SIG_ERR) {
 396                 fprintf(stderr, "Cannot set SIGALRM: %m\n");
 397                 return 2;
 398         }
 399
 400         udev_list_node_init(&bunch);
 401
 402         if (debug)
 403                 fprintf(stderr, "Using checkpoint '%s'\n", checkpoint);
 404
 405         strscpyl(tmpdir, sizeof(tmpdir), "/run/udev/collect", NULL);
 406         fd = prepare(tmpdir, checkpoint);
 407         if (fd < 0) {
 408                 ret = 3;
 409                 goto out;
 410         }
 411
 412         if (checkout(fd) < 0) {
 413                 ret = 2;
 414                 goto out;
 415         }
 416
 417         for (i = argi; i < argc; i++) {
 418                 struct udev_list_node *him_node;
 419                 struct _mate *who;
 420
 421                 who = NULL;
 422                 udev_list_node_foreach(him_node, &bunch) {
 423                         struct _mate *him = node_to_mate(him_node);
 424
 425                         if (streq(him->name, argv[i]))
 426                                 who = him;
 427                 }
 428                 if (!who) {
 429                         struct _mate *him;
 430
 431                         if (debug)
 432                                 fprintf(stderr, "ID %s: not in database\n", argv[i]);
 433                         him = new(struct _mate, 1);
 434                         if (!him) {
 435                                 ret = ENOMEM;
 436                                 goto out;
 437                         }
 438
 439                         him->name = strdup(argv[i]);
 440                         if (!him->name) {
 441                                 free(him);
 442                                 ret = ENOMEM;
 443                                 goto out;
 444                         }
 445
 446                         him->state = STATE_NONE;
 447                         udev_list_node_append(&him->node, &bunch);
 448                 } else {
 449                         if (debug)
 450                                 fprintf(stderr, "ID %s: found in database\n", argv[i]);
 451                         who->state = STATE_CONFIRMED;
 452                 }
 453         }
 454
 455         if (prune)
 456                 reject(us);
 457         else
 458                 invite(us);
 459
 460         if (debug) {
 461                 everybody();
 462                 fprintf(stderr, "Prune lists\n");
 463         }
 464         kickout();
 465
 466         lseek(fd, 0, SEEK_SET);
 467         ftruncate(fd, 0);
 468         ret = missing(fd);
 469
 470         lockf(fd, F_ULOCK, 0);
 471         close(fd);
 472 out:
 473         if (debug)
 474                 everybody();
 475         if (ret >= 0)
 476                 printf("COLLECT_%s=%d\n", checkpoint, ret);
 477         return ret;
 478 }