src/udev/udev-builtin-hwdb.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <fnmatch.h>
   5 #include <getopt.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8
   9 #include "sd-hwdb.h"
  10
  11 #include "alloc-util.h"
  12 #include "device-util.h"
  13 #include "hwdb-util.h"
  14 #include "parse-util.h"
  15 #include "string-util.h"
  16 #include "udev-builtin.h"
  17
  18 static sd_hwdb *hwdb;
  19
  20 int udev_builtin_hwdb_lookup(sd_device *dev,
  21                              const char *prefix, const char *modalias,
  22                              const char *filter, bool test) {
  23         _cleanup_free_ char *lookup = NULL;
  24         const char *key, *value;
  25         int n = 0, r;
  26
  27         if (!hwdb)
  28                 return -ENOENT;
  29
  30         if (prefix) {
  31                 lookup = strjoin(prefix, modalias);
  32                 if (!lookup)
  33                         return -ENOMEM;
  34                 modalias = lookup;
  35         }
  36
  37         SD_HWDB_FOREACH_PROPERTY(hwdb, modalias, key, value) {
  38                 if (filter && fnmatch(filter, key, FNM_NOESCAPE) != 0)
  39                         continue;
  40
  41                 r = udev_builtin_add_property(dev, test, key, value);
  42                 if (r < 0)
  43                         return r;
  44                 n++;
  45         }
  46         return n;
  47 }
  48
  49 static const char *modalias_usb(sd_device *dev, char *s, size_t size) {
  50         const char *v, *p, *n = NULL;
  51         uint16_t vn, pn;
  52
  53         if (sd_device_get_sysattr_value(dev, "idVendor", &v) < 0)
  54                 return NULL;
  55         if (sd_device_get_sysattr_value(dev, "idProduct", &p) < 0)
  56                 return NULL;
  57         if (safe_atoux16(v, &vn) < 0)
  58                 return NULL;
  59         if (safe_atoux16(p, &pn) < 0)
  60                 return NULL;
  61         (void) sd_device_get_sysattr_value(dev, "product", &n);
  62
  63         snprintf(s, size, "usb:v%04Xp%04X:%s", vn, pn, strempty(n));
  64         return s;
  65 }
  66
  67 static int udev_builtin_hwdb_search(sd_device *dev, sd_device *srcdev,
  68                                     const char *subsystem, const char *prefix,
  69                                     const char *filter, bool test) {
  70         char s[LINE_MAX];
  71         bool last = false;
  72         int r = 0;
  73
  74         assert(dev);
  75
  76         if (!srcdev)
  77                 srcdev = dev;
  78
  79         for (sd_device *d = srcdev; d; ) {
  80                 const char *dsubsys, *devtype, *modalias = NULL;
  81
  82                 if (sd_device_get_subsystem(d, &dsubsys) < 0)
  83                         goto next;
  84
  85                 /* look only at devices of a specific subsystem */
  86                 if (subsystem && !streq(dsubsys, subsystem))
  87                         goto next;
  88
  89                 (void) sd_device_get_property_value(d, "MODALIAS", &modalias);
  90
  91                 if (streq(dsubsys, "usb") &&
  92                     sd_device_get_devtype(d, &devtype) >= 0 &&
  93                     streq(devtype, "usb_device")) {
  94                         /* if the usb_device does not have a modalias, compose one */
  95                         if (!modalias)
  96                                 modalias = modalias_usb(d, s, sizeof(s));
  97
  98                         /* avoid looking at any parent device, they are usually just a USB hub */
  99                         last = true;
 100                 }
 101
 102                 if (!modalias)
 103                         goto next;
 104
 105                 log_device_debug(dev, "hwdb modalias key: \"%s\"", modalias);
 106
 107                 r = udev_builtin_hwdb_lookup(dev, prefix, modalias, filter, test);
 108                 if (r > 0)
 109                         break;
 110
 111                 if (last)
 112                         break;
 113 next:
 114                 if (sd_device_get_parent(d, &d) < 0)
 115                         break;
 116         }
 117
 118         return r;
 119 }
 120
 121 static int builtin_hwdb(sd_device *dev, int argc, char *argv[], bool test) {
 122         static const struct option options[] = {
 123                 { "filter", required_argument, NULL, 'f' },
 124                 { "device", required_argument, NULL, 'd' },
 125                 { "subsystem", required_argument, NULL, 's' },
 126                 { "lookup-prefix", required_argument, NULL, 'p' },
 127                 {}
 128         };
 129         const char *filter = NULL;
 130         const char *device = NULL;
 131         const char *subsystem = NULL;
 132         const char *prefix = NULL;
 133         _cleanup_(sd_device_unrefp) sd_device *srcdev = NULL;
 134         int r;
 135
 136         if (!hwdb)
 137                 return -EINVAL;
 138
 139         for (;;) {
 140                 int option;
 141
 142                 option = getopt_long(argc, argv, "f:d:s:p:", options, NULL);
 143                 if (option == -1)
 144                         break;
 145
 146                 switch (option) {
 147                 case 'f':
 148                         filter = optarg;
 149                         break;
 150
 151                 case 'd':
 152                         device = optarg;
 153                         break;
 154
 155                 case 's':
 156                         subsystem = optarg;
 157                         break;
 158
 159                 case 'p':
 160                         prefix = optarg;
 161                         break;
 162                 }
 163         }
 164
 165         /* query a specific key given as argument */
 166         if (argv[optind]) {
 167                 r = udev_builtin_hwdb_lookup(dev, prefix, argv[optind], filter, test);
 168                 if (r < 0)
 169                         return log_device_debug_errno(dev, r, "Failed to look up hwdb: %m");
 170                 if (r == 0)
 171                         return log_device_debug_errno(dev, SYNTHETIC_ERRNO(ENODATA), "No entry found from hwdb.");
 172                 return r;
 173         }
 174
 175         /* read data from another device than the device we will store the data */
 176         if (device) {
 177                 r = sd_device_new_from_device_id(&srcdev, device);
 178                 if (r < 0)
 179                         return log_device_debug_errno(dev, r, "Failed to create sd_device object '%s': %m", device);
 180         }
 181
 182         r = udev_builtin_hwdb_search(dev, srcdev, subsystem, prefix, filter, test);
 183         if (r < 0)
 184                 return log_device_debug_errno(dev, r, "Failed to look up hwdb: %m");
 185         if (r == 0)
 186                 return log_device_debug_errno(dev, SYNTHETIC_ERRNO(ENODATA), "No entry found from hwdb.");
 187         return r;
 188 }
 189
 190 /* called at udev startup and reload */
 191 static int builtin_hwdb_init(void) {
 192         int r;
 193
 194         if (hwdb)
 195                 return 0;
 196
 197         r = sd_hwdb_new(&hwdb);
 198         if (r < 0)
 199                 return r;
 200
 201         return 0;
 202 }
 203
 204 /* called on udev shutdown and reload request */
 205 static void builtin_hwdb_exit(void) {
 206         hwdb = sd_hwdb_unref(hwdb);
 207 }
 208
 209 /* called every couple of seconds during event activity; 'true' if config has changed */
 210 static bool builtin_hwdb_validate(void) {
 211         return hwdb_validate(hwdb);
 212 }
 213
 214 const UdevBuiltin udev_builtin_hwdb = {
 215         .name = "hwdb",
 216         .cmd = builtin_hwdb,
 217         .init = builtin_hwdb_init,
 218         .exit = builtin_hwdb_exit,
 219         .validate = builtin_hwdb_validate,
 220         .help = "Hardware database",
 221 };