diff options
| -rw-r--r-- | util-linux/mdev.c | 47 |
1 files changed, 35 insertions, 12 deletions
diff --git a/util-linux/mdev.c b/util-linux/mdev.c index 1d741367e..e80b58f2e 100644 --- a/util-linux/mdev.c +++ b/util-linux/mdev.c @@ -295,8 +295,8 @@ struct globals { /* Prevent infinite loops in /sys symlinks */ #define MAX_SYSFS_DEPTH 3 -/* We use additional 64+ bytes in make_device() */ -#define SCRATCH_SIZE 80 +/* We use additional bytes in make_device() */ +#define SCRATCH_SIZE 128 #if ENABLE_FEATURE_MDEV_CONF @@ -541,7 +541,7 @@ static char *build_alias(char *alias, const char *device_name) /* mknod in /dev based on a path like "/sys/block/hda/hda1" * NB1: path parameter needs to have SCRATCH_SIZE scratch bytes - * after NUL, but we promise to not mangle (IOW: to restore if needed) + * after NUL, but we promise to not mangle (IOW: to restore NUL if needed) * path string. * NB2: "mdev -s" may call us many times, do not leak memory/fds! * @@ -551,6 +551,7 @@ static char *build_alias(char *alias, const char *device_name) static void make_device(char *device_name, char *path, int operation) { int major, minor, type, len; + char *path_end = path + strlen(path); /* Try to read major/minor string. Note that the kernel puts \n after * the data, so we don't need to worry about null terminating the string @@ -559,17 +560,15 @@ static void make_device(char *device_name, char *path, int operation) */ major = -1; if (operation == OP_add) { - char *dev_maj_min = path + strlen(path); - - strcpy(dev_maj_min, "/dev"); - len = open_read_close(path, dev_maj_min + 1, 64); - *dev_maj_min = '\0'; + strcpy(path_end, "/dev"); + len = open_read_close(path, path_end + 1, SCRATCH_SIZE - 1); + *path_end = '\0'; if (len < 1) { if (!ENABLE_FEATURE_MDEV_EXEC) return; /* no "dev" file, but we can still run scripts * based on device name */ - } else if (sscanf(++dev_maj_min, "%u:%u", &major, &minor) == 2) { + } else if (sscanf(path_end + 1, "%u:%u", &major, &minor) == 2) { dbg1("dev %u,%u", major, minor); } else { major = -1; @@ -577,9 +576,33 @@ static void make_device(char *device_name, char *path, int operation) } /* else: for delete, -1 still deletes the node, but < -1 suppresses that */ - /* Determine device name, type, major and minor */ - if (!device_name) - device_name = (char*) bb_basename(path); + /* Determine device name */ + if (!device_name) { + /* + * There was no $DEVNAME envvar (for example, mdev -s never has). + * But it is very useful: it contains the *path*, not only basename, + * Thankfully, uevent file has it. + * Example of .../sound/card0/controlC0/uevent file on Linux-3.7.7: + * MAJOR=116 + * MINOR=7 + * DEVNAME=snd/controlC0 + */ + strcpy(path_end, "/uevent"); + len = open_read_close(path, path_end + 1, SCRATCH_SIZE - 1); + if (len < 0) + len = 0; + *path_end = '\0'; + path_end[1 + len] = '\0'; + device_name = strstr(path_end + 1, "\nDEVNAME="); + if (device_name) { + device_name += sizeof("\nDEVNAME=")-1; + strchrnul(device_name, '\n')[0] = '\0'; + } else { + /* Fall back to just basename */ + device_name = (char*) bb_basename(path); + } + } + /* Determine device type */ /* * http://kernel.org/doc/pending/hotplug.txt says that only * "/sys/block/..." is for block devices. "/sys/bus" etc is not. |