devices.c

   1 /*
   2  * Routines for parsing /proc/devices for use by the ioctl fuzzer.
   3  */
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <sys/stat.h>
   8 #include <sys/types.h>
   9 #include <linux/kdev_t.h>
  10 #include "files.h"
  11
  12 #include "log.h"
  13
  14 static struct {
  15         int major;
  16         int minor;
  17         const char *name;
  18 } *block_devs, *char_devs, *misc_devs;
  19
  20 static size_t bldevs, chrdevs, miscdevs;
  21
  22 static void parse_proc_devices(void)
  23 {
  24         FILE *fp;
  25         char *p, *name, *line = NULL;
  26         size_t n = 0;
  27         int block, major;
  28         void *new;
  29
  30         fp = fopen("/proc/devices", "r");
  31         if (!fp)
  32                 return;
  33
  34         block = 0;
  35
  36         while (getline(&line, &n, fp) >= 0) {
  37                 if (strcmp("Block devices:\n", line) == 0)
  38                         block = 1;
  39                 else if (strcmp("Character devices:\n", line) == 0)
  40                         block = 0;
  41                 else if (sscanf(line, "%d %*s", &major) == 1) {
  42                         if ((p = strchr(line, '\n')) != NULL)
  43                                 *p = 0;
  44                         if ((p = strrchr(line, ' ')) == NULL)
  45                                 continue;
  46                         p++;
  47                         name = strdup(p);
  48
  49                         if (block) {
  50                                 new = realloc(block_devs, (bldevs+1)*sizeof(*block_devs));
  51                                 if (!new) {     // FIXME: We should propagate failure up here.
  52                                         free(name);
  53                                         break;
  54                                 }
  55                                 block_devs = new;
  56                                 block_devs[bldevs].major = major;
  57                                 block_devs[bldevs].minor = 0;
  58                                 block_devs[bldevs].name = name;
  59                                 bldevs++;
  60                         } else {
  61                                 new = realloc(char_devs, (chrdevs+1)*sizeof(*char_devs));
  62                                 if (!new) {
  63                                         free(name);
  64                                         break;
  65                                 }
  66                                 char_devs = new;
  67                                 char_devs[chrdevs].major = major;
  68                                 char_devs[chrdevs].minor = 0;
  69                                 char_devs[chrdevs].name = name;
  70                                 chrdevs++;
  71                         }
  72                 }
  73         }
  74
  75         fclose(fp);
  76         free(line);
  77 }
  78
  79 static void parse_proc_misc(void)
  80 {
  81         FILE *fp;
  82         char *name;
  83         int minor;
  84         void *new;
  85
  86         fp = fopen("/proc/misc", "r");
  87         if (!fp)
  88                 return;
  89
  90         while (fscanf(fp, "%d %as", &minor, &name) == 2) {
  91                 new = realloc(misc_devs, (miscdevs+1)*sizeof(*misc_devs));
  92                 if (!new) {
  93                         free(name);
  94                         break;
  95                 }
  96                 misc_devs = new;
  97                 misc_devs[miscdevs].major = 0;
  98                 misc_devs[miscdevs].minor = minor;
  99                 misc_devs[miscdevs].name = name;
 100                 miscdevs++;
 101         }
 102
 103         fclose(fp);
 104 }
 105
 106 void parse_devices(void)
 107 {
 108         parse_proc_devices();
 109         parse_proc_misc();
 110
 111         output(2, "Parsed %zu char devices, %zu block devices, %zu misc devices.\n",
 112                         chrdevs, bldevs, miscdevs);
 113 }
 114
 115 const char *map_dev(dev_t st_rdev, mode_t st_mode)
 116 {
 117         int major, minor;
 118         size_t i, j;
 119
 120         major = MAJOR(st_rdev);
 121         minor = MINOR(st_rdev);
 122
 123         if (S_ISCHR(st_mode)) {
 124                 for (i = 0; i < chrdevs; ++i) {
 125                         if (char_devs[i].major == major) {
 126                                 if (strcmp(char_devs[i].name, "misc") == 0) {
 127                                         for (j=0; j < miscdevs; ++j)
 128                                                 if (misc_devs[j].minor == minor)
 129                                                         return misc_devs[j].name;
 130                                 } else
 131                                         return char_devs[i].name;
 132                         }
 133                 }
 134         } else if (S_ISBLK(st_mode)) {
 135                 for (i = 0; i < bldevs; ++i) {
 136                         if (block_devs[i].major == major)
 137                                 return block_devs[i].name;
 138                 }
 139         }
 140
 141         return NULL;
 142 }