share/examples/refuse/dmesgfs/dmesgfs.c

   1 /*
   2  * Copyright © 2007 Alistair Crooks.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. The name of the author may not be used to endorse or promote
  13  *    products derived from this software without specific prior written
  14  *    permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
  17  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  20  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  22  * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  24  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  25  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  26  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28 #include <sys/types.h>
  29
  30 #include <err.h>
  31 #include <errno.h>
  32 #include <fcntl.h>
  33 #include <fuse.h>
  34 #include <regex.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <unistd.h>
  39
  40 #include "virtdir.h"
  41 #include "defs.h"
  42
  43 static int               verbose; /* how chatty are we? */
  44
  45 static virtdir_t         pci;
  46
  47 /* a device node describes the device that is printed in the dmesg */
  48 typedef struct devicenode_t {
  49         char    *dev;           /* device name */
  50         int      devlen;        /* length of name */
  51         char    *parent;        /* its parent device name */
  52         int      parentlen;     /* length of parent name */
  53         char    *descr;         /* description of the device itself */
  54         int      descrlen;      /* length of description */
  55         int      p;             /* device node subscript of parent */
  56         int      dir;           /* nonzero if this is a directory */
  57 } devicenode_t;
  58
  59 DEFINE_ARRAY(devices_t, devicenode_t);
  60
  61 static devices_t        devices;
  62
  63
  64 /* perform the stat operation */
  65 /* if this is the root, then just synthesise the data */
  66 static int
  67 dmesgfs_getattr(const char *path, struct stat *st)
  68 {
  69         virt_dirent_t   *ep;
  70
  71         if (strcmp(path, "/") == 0) {
  72                 (void) memset(st, 0x0, sizeof(*st));
  73                 st->st_mode = (S_IFDIR | 0755);
  74                 st->st_nlink = 2;
  75                 return 0;
  76         }
  77         if ((ep = virtdir_find(&pci, path, strlen(path))) == NULL) {
  78                 return -ENOENT;
  79         }
  80         switch(ep->type) {
  81         case 'f':
  82                 (void) memcpy(st, &pci.file, sizeof(*st));
  83                 st->st_size = ep->tgtlen;
  84                 st->st_mode = S_IFREG | 0644;
  85                 break;
  86         case 'd':
  87                 (void) memcpy(st, &pci.dir, sizeof(*st));
  88                 break;
  89         case 'l':
  90                 (void) memcpy(st, &pci.lnk, sizeof(*st));
  91                 st->st_size = ep->tgtlen;
  92                 st->st_mode = S_IFLNK | 0755;
  93                 break;
  94         }
  95         st->st_ino = virtdir_offset(&pci, ep) + 10;
  96         return 0;
  97 }
  98
  99 /* readdir operation */
 100 static int
 101 dmesgfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
 102               off_t offset, struct fuse_file_info * fi)
 103 {
 104         static VIRTDIR  *dirp;
 105         virt_dirent_t   *dp;
 106
 107         if (offset == 0) {
 108                 if ((dirp = openvirtdir(&pci, path)) == NULL) {
 109                         return 0;
 110                 }
 111                 filler(buf, ".", NULL, 0);
 112                 filler(buf, "..", NULL, 0);
 113         }
 114         while ((dp = readvirtdir(dirp)) != NULL) {
 115                 if (filler(buf, dp->d_name, NULL, 0) != 0) {
 116                         return 0;
 117                 }
 118         }
 119         closevirtdir(dirp);
 120         dirp = NULL;
 121         return 0;
 122 }
 123
 124 /* open the file in the file system */
 125 static int
 126 dmesgfs_open(const char *path, struct fuse_file_info * fi)
 127 {
 128         return 0;
 129 }
 130
 131 /* read the file's contents in the file system */
 132 static int
 133 dmesgfs_read(const char *path, char *buf, size_t size, off_t offset,
 134            struct fuse_file_info * fi)
 135 {
 136         virt_dirent_t   *ep;
 137
 138         if ((ep = virtdir_find(&pci, path, strlen(path))) == NULL) {
 139                 return -ENOENT;
 140         }
 141         if (ep->tgt == NULL) {
 142                 return -ENOENT;
 143         }
 144         (void) memcpy(buf, &ep->tgt[offset], size);
 145         return ep->tgtlen;
 146 }
 147
 148 /* fill in the statvfs struct */
 149 static int
 150 dmesgfs_statfs(const char *path, struct statvfs *st)
 151 {
 152         (void) memset(st, 0x0, sizeof(*st));
 153         return 0;
 154 }
 155
 156 /* read the symbolic link */
 157 static int
 158 dmesgfs_readlink(const char *path, char *buf, size_t size)
 159 {
 160         virt_dirent_t   *ep;
 161
 162         if ((ep = virtdir_find(&pci, path, strlen(path))) == NULL) {
 163                 return -ENOENT;
 164         }
 165         if (ep->tgt == NULL) {
 166                 return -ENOENT;
 167         }
 168         (void) strlcpy(buf, ep->tgt, size);
 169         return 0;
 170 }
 171
 172 /* operations struct */
 173 static struct fuse_operations dmesgfs_oper = {
 174         .getattr = dmesgfs_getattr,
 175         .readlink = dmesgfs_readlink,
 176         .readdir = dmesgfs_readdir,
 177         .open = dmesgfs_open,
 178         .read = dmesgfs_read,
 179         .statfs = dmesgfs_statfs
 180 };
 181
 182 /* save `n' chars of `s' in malloc'd memory */
 183 static char *
 184 strnsave(const char *s, int n)
 185 {
 186         char    *cp;
 187
 188         if (n < 0) {
 189                 n = strlen(s);
 190         }
 191         NEWARRAY(char, cp, n + 1, "strnsave", exit(EXIT_FAILURE));
 192         (void) memcpy(cp, s, n);
 193         cp[n] = 0x0;
 194         return cp;
 195 }
 196
 197 /* find a device in the device node tree */
 198 static int
 199 finddev(const char *s, int len, int updir)
 200 {
 201         int     i;
 202
 203         for (i = 0 ; i < devices.c ; i++) {
 204                 if (strncmp(devices.v[i].dev, s, len) == 0 &&
 205                     devices.v[i].devlen == len) {
 206                         if (updir) {
 207                                 devices.v[i].dir = 1;
 208                         }
 209                         return i;
 210                 }
 211         }
 212         return -1;
 213 }
 214
 215 /* add a device to the device node tree */
 216 static void
 217 add_dev(const char *dev, int len, const char *parent, int parentlen, const char *descr, int descrlen)
 218 {
 219         int     d;
 220
 221         if ((d = finddev(dev, len, 0)) < 0) {
 222                 ALLOC(devicenode_t, devices.v, devices.size, devices.c, 10, 10, "add_dev", exit(EXIT_FAILURE));
 223                 devices.v[devices.c].dev = strnsave(dev, len);
 224                 devices.v[devices.c].devlen = len;
 225                 devices.v[devices.c].parent = strnsave(parent, parentlen);
 226                 devices.v[devices.c].parentlen = parentlen;
 227                 devices.v[devices.c].descr = strnsave(descr, descrlen);
 228                 devices.v[devices.c].descrlen = descrlen;
 229                 devices.c += 1;
 230         }
 231 }
 232
 233 /* print the parent device pathname */
 234 static int
 235 pparent(int d, char *buf, size_t size)
 236 {
 237         int     cc;
 238
 239         if (d != 0) {
 240                 cc = pparent(devices.v[d].p, buf, size);
 241                 size -= cc;
 242         }
 243         (void) strlcat(buf, "/", size);
 244         (void) strlcat(buf, devices.v[d].dev, size - 1);
 245         return devices.v[d].devlen + 1;
 246 }
 247
 248 #define NEXUS_DESCRIPTION       "Nexus - the root of everything"
 249
 250 /* build up a fuse_tree from the information in the database */
 251 static int
 252 build_tree(virtdir_t *tp, const char *nexus, char type)
 253 {
 254         struct stat      dir;
 255         struct stat      f;
 256         regmatch_t       matchv[10];
 257         regex_t          r;
 258         FILE            *pp;
 259         char             buf[BUFSIZ];
 260         int              i;
 261         int              p;
 262
 263         (void) stat(".", &dir);
 264         (void) memcpy(&f, &dir, sizeof(f));
 265         f.st_mode = S_IFREG | 0644;
 266         if (regcomp(&r, "^([a-z0-9]+) at ([a-z0-9]+)(.*)", REG_EXTENDED) != 0) {
 267                 warn("can't compile regular expression\n");
 268                 return 0;
 269         }
 270         if ((pp = popen("dmesg", "r")) == NULL) {
 271                 return 0;
 272         }
 273         add_dev(nexus, strlen(nexus), nexus, strlen(nexus), NEXUS_DESCRIPTION,
 274                 strlen(NEXUS_DESCRIPTION));
 275         while (fgets(buf, sizeof(buf), pp) != NULL) {
 276                 if (type == 'l') {
 277                         buf[strlen(buf) - 1] = 0x0;
 278                 }
 279                 if (regexec(&r, buf, 10, matchv, 0) == 0) {
 280                         add_dev(&buf[matchv[1].rm_so],
 281                                 matchv[1].rm_eo - matchv[1].rm_so,
 282                                 &buf[matchv[2].rm_so],
 283                                 matchv[2].rm_eo - matchv[2].rm_so,
 284                                 buf,
 285                                 matchv[0].rm_eo - matchv[0].rm_so);
 286                 }
 287         }
 288         printf("%d devices\n", devices.c);
 289         (void) pclose(pp);
 290         for (i = 0 ; i < devices.c ; i++) {
 291                 if ((p = finddev(devices.v[i].parent, devices.v[i].parentlen, 1)) < 0) {
 292                         warn("No parent device for %s\n", devices.v[i].dev);
 293                 }
 294                 devices.v[i].p = p;
 295         }
 296         for (i = 0 ; i < devices.c ; i++) {
 297                 pparent(i, buf, sizeof(buf));
 298                 virtdir_add(tp, buf, strlen(buf),
 299                         (devices.v[i].dir) ? 'd' : type,
 300                         devices.v[i].descr, devices.v[i].descrlen);
 301                 if (devices.v[i].dir) {
 302                         (void) strlcat(buf, "/", sizeof(buf));
 303                         (void) strlcat(buf, "Description", sizeof(buf));
 304                         virtdir_add(tp, buf, strlen(buf), type,
 305                                 devices.v[i].descr, devices.v[i].descrlen);
 306                 }
 307                 if (verbose) {
 308                         printf("dmesgfs: adding %s `%s' -> `%s'\n",
 309                                 (type == 'l') ? "symbolic link" : "file",
 310                                 buf, devices.v[i].descr);
 311                 }
 312                 buf[0] = 0x0;
 313         }
 314         return 1;
 315 }
 316
 317 int
 318 main(int argc, char **argv)
 319 {
 320         char    *nexus;
 321         char     type;
 322         int      i;
 323
 324         nexus = NULL;
 325         type = 'l';
 326         while ((i = getopt(argc, argv, "fln:v")) != -1) {
 327                 switch(i) {
 328                 case 'f':
 329                         type = 'f';
 330                         break;
 331                 case 'l':
 332                         type = 'l';
 333                         break;
 334                 case 'n':
 335                         nexus = optarg;
 336                         break;
 337                 case 'v':
 338                         verbose += 1;
 339                         break;
 340                 }
 341         }
 342         if (!build_tree(&pci, (nexus) ? nexus : "mainbus0", type)) {
 343                 exit(EXIT_FAILURE);
 344         }
 345         return fuse_main(argc, argv, &dmesgfs_oper, NULL);
 346 }