libfrog/paths.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2005-2006 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6
   7 #include <paths.h>
   8 #include <errno.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13 #include <sys/types.h>
  14 #include <sys/stat.h>
  15 #include "paths.h"
  16 #include "input.h"
  17 #include "projects.h"
  18 #include <limits.h>
  19
  20 extern char *progname;
  21
  22 int fs_count;
  23 int xfs_fs_count;
  24 struct fs_path *fs_table;
  25 struct fs_path *fs_path;
  26
  27 char *mtab_file;
  28 #define PROC_MOUNTS     "/proc/self/mounts"
  29
  30 static int
  31 fs_device_number(
  32         const char      *name,
  33         dev_t           *devnum)
  34 {
  35         struct stat     sbuf;
  36
  37         if (stat(name, &sbuf) < 0)
  38                 return errno;
  39         /*
  40          * We want to match st_rdev if the path provided is a device
  41          * special file.  Otherwise we are looking for the the
  42          * device id for the containing filesystem, in st_dev.
  43          */
  44         if (S_ISBLK(sbuf.st_mode) || S_ISCHR(sbuf.st_mode))
  45                 *devnum = sbuf.st_rdev;
  46         else
  47                 *devnum = sbuf.st_dev;
  48
  49         return 0;
  50 }
  51
  52 /*
  53  * Find the FS table entry for the given path.  The "flags" argument
  54  * is a mask containing FS_MOUNT_POINT or FS_PROJECT_PATH (or both)
  55  * to indicate the type of table entry sought.
  56  * fs_table_lookup() finds the fs table entry for the filesystem hosting
  57  * the file represented in the "dir" argument. To compare against actual
  58  * mount point entries, use fs_table_lookup_mount() instead.
  59  */
  60 struct fs_path *
  61 fs_table_lookup(
  62         const char      *dir,
  63         uint            flags)
  64 {
  65         uint            i;
  66         dev_t           dev = 0;
  67
  68         if (fs_device_number(dir, &dev))
  69                 return NULL;
  70
  71         for (i = 0; i < fs_count; i++) {
  72                 if (flags && !(flags & fs_table[i].fs_flags))
  73                         continue;
  74                 if (fs_table[i].fs_datadev == dev)
  75                         return &fs_table[i];
  76         }
  77         return NULL;
  78 }
  79
  80 static struct fs_path *
  81 __fs_table_lookup_mount(
  82         const char      *dir,
  83         const char      *blkdev)
  84 {
  85         uint            i;
  86         char            rpath[PATH_MAX];
  87         char            dpath[PATH_MAX];
  88
  89         if (!dir && !blkdev)
  90                 return NULL;
  91
  92         if (dir && !realpath(dir, dpath))
  93                 return NULL;
  94         if (blkdev && !realpath(blkdev, dpath))
  95                 return NULL;
  96
  97         for (i = 0; i < fs_count; i++) {
  98                 if (fs_table[i].fs_flags != FS_MOUNT_POINT)
  99                         continue;
 100                 if (dir && !realpath(fs_table[i].fs_dir, rpath))
 101                         continue;
 102                 if (blkdev && !realpath(fs_table[i].fs_name, rpath))
 103                         continue;
 104                 if (strcmp(rpath, dpath) == 0)
 105                         return &fs_table[i];
 106         }
 107         return NULL;
 108 }
 109
 110 /*
 111  * Find the FS table entry describing an actual mount for the given path.
 112  * Unlike fs_table_lookup(), fs_table_lookup_mount() compares the "dir"
 113  * argument to actual mount point entries in the table. Accordingly, it
 114  * will find matches only if the "dir" argument is indeed mounted.
 115  */
 116 struct fs_path *
 117 fs_table_lookup_mount(
 118         const char      *dir)
 119 {
 120         return __fs_table_lookup_mount(dir, NULL);
 121 }
 122
 123 /*
 124  * Find the FS table entry describing an actual mount for the block device.
 125  * Unlike fs_table_lookup(), fs_table_lookup_blkdev() compares the "bdev"
 126  * argument to actual mount point names in the table. Accordingly, it
 127  * will find matches only if the "bdev" argument is indeed mounted.
 128  */
 129 struct fs_path *
 130 fs_table_lookup_blkdev(
 131         const char      *bdev)
 132 {
 133         return __fs_table_lookup_mount(NULL, bdev);
 134 }
 135
 136 static int
 137 fs_table_insert(
 138         char            *dir,
 139         uint            prid,
 140         uint            flags,
 141         char            *fsname,
 142         char            *fslog,
 143         char            *fsrt)
 144 {
 145         dev_t           datadev, logdev, rtdev;
 146         struct fs_path  *tmp_fs_table;
 147         int             error;
 148
 149         datadev = logdev = rtdev = 0;
 150         error = fs_device_number(dir, &datadev);
 151         if (error)
 152                 goto out_nodev;
 153         if (fslog) {
 154                 error = fs_device_number(fslog, &logdev);
 155                 if (error)
 156                         goto out_nodev;
 157         }
 158         if (fsrt) {
 159                 error = fs_device_number(fsrt, &rtdev);
 160                 if (error)
 161                         goto out_nodev;
 162         }
 163
 164         if (!platform_test_xfs_path(dir))
 165                 flags |= FS_FOREIGN;
 166
 167         /*
 168          * Make copies of the directory and data device path.
 169          * The log device and real-time device, if non-null,
 170          * are already the result of strdup() calls so we
 171          * don't need to duplicate those.  In fact, this
 172          * function is assumed to "consume" both of those
 173          * pointers, meaning if an error occurs they will
 174          * both get freed.
 175          */
 176         error = ENOMEM;
 177         dir = strdup(dir);
 178         if (!dir)
 179                 goto out_nodev;
 180         fsname = strdup(fsname);
 181         if (!fsname)
 182                 goto out_noname;
 183
 184         tmp_fs_table = realloc(fs_table, sizeof(fs_path_t) * (fs_count + 1));
 185         if (!tmp_fs_table)
 186                 goto out_norealloc;
 187         fs_table = tmp_fs_table;
 188
 189         /* Put foreign filesystems at the end, xfs filesystems at the front */
 190         if (flags & FS_FOREIGN || fs_count == 0) {
 191                 fs_path = &fs_table[fs_count];
 192         } else {
 193                 /* move foreign fs entries down, insert new one just before */
 194                 memmove(&fs_table[xfs_fs_count + 1], &fs_table[xfs_fs_count],
 195                         sizeof(fs_path_t)*(fs_count - xfs_fs_count));
 196                 fs_path = &fs_table[xfs_fs_count];
 197         }
 198         fs_path->fs_dir = dir;
 199         fs_path->fs_prid = prid;
 200         fs_path->fs_flags = flags;
 201         fs_path->fs_name = fsname;
 202         fs_path->fs_log = fslog;
 203         fs_path->fs_rt = fsrt;
 204         fs_path->fs_datadev = datadev;
 205         fs_path->fs_logdev = logdev;
 206         fs_path->fs_rtdev = rtdev;
 207         fs_count++;
 208         if (!(flags & FS_FOREIGN))
 209                 xfs_fs_count++;
 210
 211         return 0;
 212
 213 out_norealloc:
 214         free(fsname);
 215 out_noname:
 216         free(dir);
 217 out_nodev:
 218         /* "Consume" fslog and fsrt even if there's an error */
 219         free(fslog);
 220         free(fsrt);
 221
 222         return error;
 223 }
 224
 225 /* Remove all the cached entries in the fs table. */
 226 void
 227 fs_table_destroy(void)
 228 {
 229         int             i;
 230         struct fs_path  *fsp;
 231
 232         for (i = 0, fsp = fs_table; i < fs_count; i++, fsp++) {
 233                 free(fsp->fs_name);
 234                 free(fsp->fs_dir);
 235                 free(fsp->fs_log);
 236                 free(fsp->fs_rt);
 237         }
 238
 239         fs_count = 0;
 240         xfs_fs_count = 0;
 241         free(fs_table);
 242         fs_table = NULL;
 243 }
 244
 245 /*
 246  * Table iteration (cursor-based) interfaces
 247  */
 248
 249 /*
 250  * Initialize an fs_table cursor.  If a directory path is supplied,
 251  * the cursor is set up to appear as though the table contains only
 252  * a single entry which represents the directory specified.
 253  * Otherwise it is set up to prepare for visiting all entries in the
 254  * global table, starting with the first.  "flags" can be either
 255  * FS_MOUNT_POINT or FS_PROJECT_PATH to limit what type of entries
 256  * will be selected by fs_cursor_next_entry().  0 can be used as a
 257  * wild card (selecting either type).
 258  */
 259 void
 260 fs_cursor_initialise(
 261         char            *dir,
 262         uint            flags,
 263         fs_cursor_t     *cur)
 264 {
 265         fs_path_t       *path;
 266
 267         memset(cur, 0, sizeof(*cur));
 268         if (dir) {
 269                 if ((path = fs_table_lookup(dir, flags)) == NULL)
 270                         return;
 271                 cur->local = *path;
 272                 cur->count = 1;
 273                 cur->table = &cur->local;
 274         } else {
 275                 cur->count = fs_count;
 276                 cur->table = fs_table;
 277         }
 278         cur->flags = flags;
 279 }
 280
 281 /*
 282  * Use the cursor to find the next entry in the table having the
 283  * type specified by the cursor's "flags" field.
 284  */
 285 struct fs_path *
 286 fs_cursor_next_entry(
 287         fs_cursor_t     *cur)
 288 {
 289         while (cur->index < cur->count) {
 290                 fs_path_t       *next = &cur->table[cur->index++];
 291
 292                 if (!cur->flags || (cur->flags & next->fs_flags))
 293                         return next;
 294         }
 295         return NULL;
 296 }
 297
 298
 299 #if defined(HAVE_GETMNTENT)
 300 #include <mntent.h>
 301
 302 /*
 303  * Determines whether the "logdev" or "rtdev" mount options are
 304  * present for the given mount point.  If so, the value for each (a
 305  * device path) is returned in the pointers whose addresses are
 306  * provided.  The pointers are assigned NULL for an option not
 307  * present.  Note that the path buffers returned are allocated
 308  * dynamically and it is the caller's responsibility to free them.
 309  */
 310 static int
 311 fs_extract_mount_options(
 312         struct mntent   *mnt,
 313         char            **logp,
 314         char            **rtp)
 315 {
 316         char            *fslog, *fsrt;
 317
 318         /*
 319          * Extract log device and realtime device from mount options.
 320          *
 321          * Note: the glibc hasmntopt implementation requires that the
 322          * character in mnt_opts immediately after the search string
 323          * must be a NULL ('\0'), a comma (','), or an equals ('=').
 324          * Therefore we cannot search for 'logdev=' directly.
 325          */
 326         if ((fslog = hasmntopt(mnt, "logdev")) && fslog[6] == '=')
 327                 fslog += 7;
 328         if ((fsrt = hasmntopt(mnt, "rtdev")) && fsrt[5] == '=')
 329                 fsrt += 6;
 330
 331         /* Do this only after we've finished processing mount options */
 332         if (fslog) {
 333                 fslog = strndup(fslog, strcspn(fslog, " ,"));
 334                 if (!fslog)
 335                         goto out_nomem;
 336         }
 337         if (fsrt) {
 338                 fsrt = strndup(fsrt, strcspn(fsrt, " ,"));
 339                 if (!fsrt) {
 340                         free(fslog);
 341                         goto out_nomem;
 342                 }
 343         }
 344         *logp = fslog;
 345         *rtp = fsrt;
 346
 347         return 0;
 348
 349 out_nomem:
 350         *logp = NULL;
 351         *rtp = NULL;
 352         fprintf(stderr, _("%s: unable to extract mount options for \"%s\"\n"),
 353                 progname, mnt->mnt_dir);
 354         return ENOMEM;
 355 }
 356
 357 /*
 358  * If *path is NULL, initialize the fs table with all xfs mount points in mtab
 359  * If *path is specified, search for that path in mtab
 360  *
 361  * Everything - path, devices, and mountpoints - are boiled down to realpath()
 362  * for comparison, but fs_table is populated with what comes from getmntent.
 363  */
 364 static int
 365 fs_table_initialise_mounts(
 366         char            *path)
 367 {
 368         struct mntent   *mnt;
 369         FILE            *mtp;
 370         char            *fslog, *fsrt;
 371         int             error, found;
 372         char            rpath[PATH_MAX], rmnt_fsname[PATH_MAX], rmnt_dir[PATH_MAX];
 373
 374         error = found = 0;
 375         fslog = fsrt = NULL;
 376
 377         if (!mtab_file) {
 378                 mtab_file = PROC_MOUNTS;
 379                 if (access(mtab_file, R_OK) != 0)
 380                         mtab_file = MOUNTED;
 381         }
 382
 383         if ((mtp = setmntent(mtab_file, "r")) == NULL)
 384                 return ENOENT;
 385
 386         /* Use realpath to resolve symlinks, relative paths, etc */
 387         if (path)
 388                 if (!realpath(path, rpath))
 389                         return errno;
 390
 391         while ((mnt = getmntent(mtp)) != NULL) {
 392                 if (!realpath(mnt->mnt_dir, rmnt_dir))
 393                         continue;
 394                 if (!realpath(mnt->mnt_fsname, rmnt_fsname))
 395                         continue;
 396
 397                 if (path &&
 398                     ((strcmp(rpath, rmnt_dir) != 0) &&
 399                      (strcmp(rpath, rmnt_fsname) != 0)))
 400                         continue;
 401                 if (fs_extract_mount_options(mnt, &fslog, &fsrt))
 402                         continue;
 403                 (void) fs_table_insert(mnt->mnt_dir, 0, FS_MOUNT_POINT,
 404                                         mnt->mnt_fsname, fslog, fsrt);
 405                 if (path) {
 406                         found = 1;
 407                         break;
 408                 }
 409         }
 410         endmntent(mtp);
 411
 412         if (path && !found)
 413                 error = ENXIO;
 414
 415         return error;
 416 }
 417
 418 #else
 419 # error "How do I extract info about mounted filesystems on this platform?"
 420 #endif
 421
 422 /*
 423  * Given a directory, match it up to a filesystem mount point.
 424  */
 425 static struct fs_path *
 426 fs_mount_point_from_path(
 427         const char      *dir)
 428 {
 429         fs_cursor_t     cursor;
 430         fs_path_t       *fs;
 431         dev_t           dev = 0;
 432
 433         if (fs_device_number(dir, &dev))
 434                 return NULL;
 435
 436         fs_cursor_initialise(NULL, FS_MOUNT_POINT, &cursor);
 437         while ((fs = fs_cursor_next_entry(&cursor))) {
 438                 if (fs->fs_datadev == dev)
 439                         break;
 440         }
 441         return fs;
 442 }
 443
 444 static void
 445 fs_table_insert_mount(
 446         char            *mount)
 447 {
 448         int             error;
 449
 450         error = fs_table_initialise_mounts(mount);
 451         if (error)
 452                 fprintf(stderr, _("%s: cannot setup path for mount %s: %s\n"),
 453                         progname, mount, strerror(error));
 454 }
 455
 456 static int
 457 fs_table_initialise_projects(
 458         char            *project)
 459 {
 460         fs_project_path_t *path;
 461         fs_path_t       *fs;
 462         prid_t          prid = 0;
 463         int             error = 0, found = 0;
 464
 465         if (project)
 466                 prid = prid_from_string(project);
 467
 468         setprpathent();
 469         while ((path = getprpathent()) != NULL) {
 470                 if (project && prid != path->pp_prid)
 471                         continue;
 472                 fs = fs_mount_point_from_path(path->pp_pathname);
 473                 if (!fs) {
 474                         fprintf(stderr, _("%s: cannot find mount point for path `%s': %s\n"),
 475                                         progname, path->pp_pathname, strerror(errno));
 476                         continue;
 477                 }
 478                 (void) fs_table_insert(path->pp_pathname, path->pp_prid,
 479                                         FS_PROJECT_PATH, fs->fs_name,
 480                                         NULL, NULL);
 481                 if (project) {
 482                         found = 1;
 483                         break;
 484                 }
 485         }
 486         endprpathent();
 487
 488         if (project && !found)
 489                 error = ENOENT;
 490
 491         return error;
 492 }
 493
 494 static void
 495 fs_table_insert_project(
 496         char            *project)
 497 {
 498         int             error;
 499
 500         error = fs_table_initialise_projects(project);
 501         if (error)
 502                 fprintf(stderr, _("%s: cannot setup path for project %s: %s\n"),
 503                         progname, project, strerror(error));
 504 }
 505
 506 /*
 507  * Initialize fs_table to contain the given set of mount points and
 508  * projects.  If mount_count is zero, mounts is ignored and the
 509  * table is populated with mounted filesystems.  If project_count is
 510  * zero, projects is ignored and the table is populated with all
 511  * projects defined in the projects file.
 512  */
 513 void
 514 fs_table_initialise(
 515         int     mount_count,
 516         char    *mounts[],
 517         int     project_count,
 518         char    *projects[])
 519 {
 520         int     error;
 521         int     i;
 522
 523         if (mount_count) {
 524                 for (i = 0; i < mount_count; i++)
 525                         fs_table_insert_mount(mounts[i]);
 526         } else {
 527                 error = fs_table_initialise_mounts(NULL);
 528                 if (error)
 529                         goto out_error;
 530         }
 531         if (project_count) {
 532                 for (i = 0; i < project_count; i++)
 533                         fs_table_insert_project(projects[i]);
 534         } else {
 535                 error = fs_table_initialise_projects(NULL);
 536                 if (error)
 537                         goto out_error;
 538         }
 539
 540         return;
 541
 542 out_error:
 543         fprintf(stderr, _("%s: cannot initialise path table: %s\n"),
 544                 progname, strerror(error));
 545 }
 546
 547 void
 548 fs_table_insert_project_path(
 549         char            *dir,
 550         prid_t          prid)
 551 {
 552         fs_path_t       *fs;
 553         int             error = 0;
 554
 555         fs = fs_mount_point_from_path(dir);
 556         if (fs)
 557                 error = fs_table_insert(dir, prid, FS_PROJECT_PATH,
 558                                         fs->fs_name, NULL, NULL);
 559         else
 560                 error = ENOENT;
 561
 562         if (error) {
 563                 fprintf(stderr, _("%s: cannot setup path for project dir %s: %s\n"),
 564                                 progname, dir, strerror(error));
 565                 exit(1);
 566         }
 567 }