c3cf1e30a
Nikolaus Voss
2013-05-13
Subject
mdev: use $DEVNAME in uevent sysfs file for device node name
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util-linux/mdev.c+35 -12
| @@ -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. | |