| /* vi: set sw=4 ts=4: */ |
| /* |
| * mdev - Mini udev for busybox |
| * |
| * Copyright 2005 Rob Landley <rob@landley.net> |
| * Copyright 2005 Frank Sorenson <frank@tuxrocks.com> |
| * |
| * Licensed under GPLv2, see file LICENSE in this source tree. |
| */ |
| #include "libbb.h" |
| #include "xregex.h" |
| |
| /* "mdev -s" scans /sys/class/xxx, looking for directories which have dev |
| * file (it is of the form "M:m\n"). Example: /sys/class/tty/tty0/dev |
| * contains "4:0\n". Directory name is taken as device name, path component |
| * directly after /sys/class/ as subsystem. In this example, "tty0" and "tty". |
| * Then mdev creates the /dev/device_name node. |
| * If /sys/class/.../dev file does not exist, mdev still may act |
| * on this device: see "@|$|*command args..." parameter in config file. |
| * |
| * mdev w/o parameters is called as hotplug helper. It takes device |
| * and subsystem names from $DEVPATH and $SUBSYSTEM, extracts |
| * maj,min from "/sys/$DEVPATH/dev" and also examines |
| * $ACTION ("add"/"delete") and $FIRMWARE. |
| * |
| * If action is "add", mdev creates /dev/device_name similarly to mdev -s. |
| * (todo: explain "delete" and $FIRMWARE) |
| * |
| * If /etc/mdev.conf exists, it may modify /dev/device_name's properties. |
| * /etc/mdev.conf file format: |
| * |
| * [-][subsystem/]device user:grp mode [>|=path] [@|$|*command args...] |
| * [-]@maj,min[-min2] user:grp mode [>|=path] [@|$|*command args...] |
| * [-]$envvar=val user:grp mode [>|=path] [@|$|*command args...] |
| * |
| * Leading minus in 1st field means "don't stop on this line", otherwise |
| * search is stopped after the matching line is encountered. |
| * |
| * The device name or "subsystem/device" combo is matched against 1st field |
| * (which is a regex), or maj,min is matched against 1st field, |
| * or specified environment variable (as regex) is matched against 1st field. |
| * |
| * $envvar=val format is useful for loading modules for hot-plugged devices |
| * which do not have driver loaded yet. In this case /sys/class/.../dev |
| * does not exist, but $MODALIAS is set to needed module's name |
| * (actually, an alias to it) by kernel. This rule instructs mdev |
| * to load the module and exit: |
| * $MODALIAS=.* 0:0 660 @modprobe "$MODALIAS" |
| * The kernel will generate another hotplug event when /sys/class/.../dev |
| * file appears. |
| * |
| * When line matches, the device node is created, chmod'ed and chown'ed, |
| * moved to path, and if >path, a symlink to moved node is created, |
| * all this if /sys/class/.../dev exists. |
| * Examples: |
| * =loop/ - moves to /dev/loop |
| * >disk/sda%1 - moves to /dev/disk/sdaN, makes /dev/sdaN a symlink |
| * |
| * Then "command args..." is executed (via sh -c 'command args...'). |
| * @:execute on creation, $:on deletion, *:on both. |
| * This happens regardless of /sys/class/.../dev existence. |
| */ |
| |
| struct globals { |
| int root_major, root_minor; |
| char *subsystem; |
| } FIX_ALIASING; |
| #define G (*(struct globals*)&bb_common_bufsiz1) |
| |
| /* Prevent infinite loops in /sys symlinks */ |
| #define MAX_SYSFS_DEPTH 3 |
| |
| /* We use additional 64+ bytes in make_device() */ |
| #define SCRATCH_SIZE 80 |
| |
| /* Builds an alias path. |
| * This function potentionally reallocates the alias parameter. |
| * Only used for ENABLE_FEATURE_MDEV_RENAME |
| */ |
| static char *build_alias(char *alias, const char *device_name) |
| { |
| char *dest; |
| |
| /* ">bar/": rename to bar/device_name */ |
| /* ">bar[/]baz": rename to bar[/]baz */ |
| dest = strrchr(alias, '/'); |
| if (dest) { /* ">bar/[baz]" ? */ |
| *dest = '\0'; /* mkdir bar */ |
| bb_make_directory(alias, 0755, FILEUTILS_RECUR); |
| *dest = '/'; |
| if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */ |
| dest = alias; |
| alias = concat_path_file(alias, device_name); |
| free(dest); |
| } |
| } |
| |
| return alias; |
| } |
| |
| /* 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) |
| * path string. |
| * NB2: "mdev -s" may call us many times, do not leak memory/fds! |
| */ |
| static void make_device(char *path, int delete) |
| { |
| char *device_name, *subsystem_slash_devname; |
| int major, minor, type, len; |
| mode_t mode; |
| parser_t *parser; |
| |
| /* 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 |
| * because sscanf() will stop at the first nondigit, which \n is. |
| * We also depend on path having writeable space after it. |
| */ |
| major = -1; |
| if (!delete) { |
| 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'; |
| 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) { |
| major = -1; |
| } |
| } |
| /* else: for delete, -1 still deletes the node, but < -1 suppresses that */ |
| |
| /* Determine device name, type, major and minor */ |
| device_name = (char*) bb_basename(path); |
| /* http://kernel.org/doc/pending/hotplug.txt says that only |
| * "/sys/block/..." is for block devices. "/sys/bus" etc is not. |
| * But since 2.6.25 block devices are also in /sys/class/block. |
| * We use strstr("/block/") to forestall future surprises. */ |
| type = S_IFCHR; |
| if (strstr(path, "/block/") || (G.subsystem && strncmp(G.subsystem, "block", 5) == 0)) |
| type = S_IFBLK; |
| |
| /* Make path point to "subsystem/device_name" */ |
| subsystem_slash_devname = NULL; |
| /* Check for coldplug invocations first */ |
| if (strncmp(path, "/sys/block/", 11) == 0) /* legacy case */ |
| path += sizeof("/sys/") - 1; |
| else if (strncmp(path, "/sys/class/", 11) == 0) |
| path += sizeof("/sys/class/") - 1; |
| else { |
| /* Example of a hotplug invocation: |
| * SUBSYSTEM="block" |
| * DEVPATH="/sys" + "/devices/virtual/mtd/mtd3/mtdblock3" |
| * ("/sys" is added by mdev_main) |
| * - path does not contain subsystem |
| */ |
| subsystem_slash_devname = concat_path_file(G.subsystem, device_name); |
| path = subsystem_slash_devname; |
| } |
| |
| /* If we have config file, look up user settings */ |
| if (ENABLE_FEATURE_MDEV_CONF) |
| parser = config_open2("/etc/mdev.conf", fopen_for_read); |
| |
| do { |
| int keep_matching; |
| struct bb_uidgid_t ugid; |
| char *tokens[4]; |
| char *command = NULL; |
| char *alias = NULL; |
| char aliaslink = aliaslink; /* for compiler */ |
| |
| /* Defaults in case we won't match any line */ |
| ugid.uid = ugid.gid = 0; |
| keep_matching = 0; |
| mode = 0660; |
| |
| if (ENABLE_FEATURE_MDEV_CONF |
| && config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL) |
| ) { |
| char *val; |
| char *str_to_match; |
| regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP]; |
| |
| val = tokens[0]; |
| keep_matching = ('-' == val[0]); |
| val += keep_matching; /* swallow leading dash */ |
| |
| /* Match against either "subsystem/device_name" |
| * or "device_name" alone */ |
| str_to_match = strchr(val, '/') ? path : device_name; |
| |
| /* Fields: regex uid:gid mode [alias] [cmd] */ |
| |
| if (val[0] == '@') { |
| /* @major,minor[-minor2] */ |
| /* (useful when name is ambiguous: |
| * "/sys/class/usb/lp0" and |
| * "/sys/class/printer/lp0") */ |
| int cmaj, cmin0, cmin1, sc; |
| if (major < 0) |
| continue; /* no dev, no match */ |
| sc = sscanf(val, "@%u,%u-%u", &cmaj, &cmin0, &cmin1); |
| if (sc < 1 |
| || major != cmaj |
| || (sc == 2 && minor != cmin0) |
| || (sc == 3 && (minor < cmin0 || minor > cmin1)) |
| ) { |
| continue; /* this line doesn't match */ |
| } |
| goto line_matches; |
| } |
| if (val[0] == '$') { |
| /* regex to match an environment variable */ |
| char *eq = strchr(++val, '='); |
| if (!eq) |
| continue; |
| *eq = '\0'; |
| str_to_match = getenv(val); |
| if (!str_to_match) |
| continue; |
| str_to_match -= strlen(val) + 1; |
| *eq = '='; |
| } |
| /* else: regex to match [subsystem/]device_name */ |
| |
| { |
| regex_t match; |
| int result; |
| |
| xregcomp(&match, val, REG_EXTENDED); |
| result = regexec(&match, str_to_match, ARRAY_SIZE(off), off, 0); |
| regfree(&match); |
| //bb_error_msg("matches:"); |
| //for (int i = 0; i < ARRAY_SIZE(off); i++) { |
| // if (off[i].rm_so < 0) continue; |
| // bb_error_msg("match %d: '%.*s'\n", i, |
| // (int)(off[i].rm_eo - off[i].rm_so), |
| // device_name + off[i].rm_so); |
| //} |
| |
| /* If no match, skip rest of line */ |
| /* (regexec returns whole pattern as "range" 0) */ |
| if (result |
| || off[0].rm_so |
| || ((int)off[0].rm_eo != (int)strlen(str_to_match)) |
| ) { |
| continue; /* this line doesn't match */ |
| } |
| } |
| line_matches: |
| /* This line matches. Stop parsing after parsing |
| * the rest the line unless keep_matching == 1 */ |
| |
| /* 2nd field: uid:gid - device ownership */ |
| if (get_uidgid(&ugid, tokens[1], 1) == 0) |
| bb_error_msg("unknown user/group %s on line %d", tokens[1], parser->lineno); |
| |
| /* 3rd field: mode - device permissions */ |
| bb_parse_mode(tokens[2], &mode); |
| |
| val = tokens[3]; |
| /* 4th field (opt): ">|=alias" or "!" to not create the node */ |
| |
| if (ENABLE_FEATURE_MDEV_RENAME && val) { |
| char *a, *s, *st; |
| |
| a = val; |
| s = strchrnul(val, ' '); |
| st = strchrnul(val, '\t'); |
| if (st < s) |
| s = st; |
| st = (s[0] && s[1]) ? s+1 : NULL; |
| |
| aliaslink = a[0]; |
| if (aliaslink == '!' && s == a+1) { |
| val = st; |
| /* "!": suppress node creation/deletion */ |
| major = -2; |
| } |
| else if (aliaslink == '>' || aliaslink == '=') { |
| val = st; |
| s[0] = '\0'; |
| if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) { |
| char *p; |
| unsigned i, n; |
| |
| /* substitute %1..9 with off[1..9], if any */ |
| n = 0; |
| s = a; |
| while (*s) |
| if (*s++ == '%') |
| n++; |
| |
| p = alias = xzalloc(strlen(a) + n * strlen(str_to_match)); |
| s = a + 1; |
| while (*s) { |
| *p = *s; |
| if ('%' == *s) { |
| i = (s[1] - '0'); |
| if (i <= 9 && off[i].rm_so >= 0) { |
| n = off[i].rm_eo - off[i].rm_so; |
| strncpy(p, str_to_match + off[i].rm_so, n); |
| p += n - 1; |
| s++; |
| } |
| } |
| p++; |
| s++; |
| } |
| } else { |
| alias = xstrdup(a + 1); |
| } |
| } |
| } |
| |
| if (ENABLE_FEATURE_MDEV_EXEC && val) { |
| const char *s = "$@*"; |
| const char *s2 = strchr(s, val[0]); |
| |
| if (!s2) { |
| bb_error_msg("bad line %u", parser->lineno); |
| if (ENABLE_FEATURE_MDEV_RENAME) |
| free(alias); |
| continue; |
| } |
| |
| /* Are we running this command now? |
| * Run $cmd on delete, @cmd on create, *cmd on both |
| */ |
| if (s2 - s != delete) { |
| /* We are here if: '*', |
| * or: '@' and delete = 0, |
| * or: '$' and delete = 1 |
| */ |
| command = xstrdup(val + 1); |
| } |
| } |
| } |
| |
| /* End of field parsing */ |
| |
| /* "Execute" the line we found */ |
| { |
| const char *node_name; |
| |
| node_name = device_name; |
| if (ENABLE_FEATURE_MDEV_RENAME && alias) |
| node_name = alias = build_alias(alias, device_name); |
| |
| if (!delete && major >= 0) { |
| if (mknod(node_name, mode | type, makedev(major, minor)) && errno != EEXIST) |
| bb_perror_msg("can't create '%s'", node_name); |
| if (major == G.root_major && minor == G.root_minor) |
| symlink(node_name, "root"); |
| if (ENABLE_FEATURE_MDEV_CONF) { |
| chmod(node_name, mode); |
| chown(node_name, ugid.uid, ugid.gid); |
| } |
| if (ENABLE_FEATURE_MDEV_RENAME && alias) { |
| if (aliaslink == '>') |
| symlink(node_name, device_name); |
| } |
| } |
| |
| if (ENABLE_FEATURE_MDEV_EXEC && command) { |
| /* setenv will leak memory, use putenv/unsetenv/free */ |
| char *s = xasprintf("%s=%s", "MDEV", node_name); |
| char *s1 = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem); |
| putenv(s); |
| putenv(s1); |
| if (system(command) == -1) |
| bb_perror_msg("can't run '%s'", command); |
| bb_unsetenv_and_free(s1); |
| bb_unsetenv_and_free(s); |
| free(command); |
| } |
| |
| if (delete && major >= -1) { |
| if (ENABLE_FEATURE_MDEV_RENAME && alias) { |
| if (aliaslink == '>') |
| unlink(device_name); |
| } |
| unlink(node_name); |
| } |
| |
| if (ENABLE_FEATURE_MDEV_RENAME) |
| free(alias); |
| } |
| |
| /* We found matching line. |
| * Stop unless it was prefixed with '-' */ |
| if (ENABLE_FEATURE_MDEV_CONF && !keep_matching) |
| break; |
| |
| /* end of "while line is read from /etc/mdev.conf" */ |
| } while (ENABLE_FEATURE_MDEV_CONF); |
| |
| if (ENABLE_FEATURE_MDEV_CONF) |
| config_close(parser); |
| free(subsystem_slash_devname); |
| } |
| |
| /* File callback for /sys/ traversal */ |
| static int FAST_FUNC fileAction(const char *fileName, |
| struct stat *statbuf UNUSED_PARAM, |
| void *userData, |
| int depth UNUSED_PARAM) |
| { |
| size_t len = strlen(fileName) - 4; /* can't underflow */ |
| char *scratch = userData; |
| |
| /* len check is for paranoid reasons */ |
| if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX) |
| return FALSE; |
| |
| strcpy(scratch, fileName); |
| scratch[len] = '\0'; |
| make_device(scratch, /*delete:*/ 0); |
| |
| return TRUE; |
| } |
| |
| /* Directory callback for /sys/ traversal */ |
| static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM, |
| struct stat *statbuf UNUSED_PARAM, |
| void *userData UNUSED_PARAM, |
| int depth) |
| { |
| /* Extract device subsystem -- the name of the directory |
| * under /sys/class/ */ |
| if (1 == depth) { |
| free(G.subsystem); |
| G.subsystem = strrchr(fileName, '/'); |
| if (G.subsystem) |
| G.subsystem = xstrdup(G.subsystem + 1); |
| } |
| |
| return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE); |
| } |
| |
| /* For the full gory details, see linux/Documentation/firmware_class/README |
| * |
| * Firmware loading works like this: |
| * - kernel sets FIRMWARE env var |
| * - userspace checks /lib/firmware/$FIRMWARE |
| * - userspace waits for /sys/$DEVPATH/loading to appear |
| * - userspace writes "1" to /sys/$DEVPATH/loading |
| * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data |
| * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading |
| * - kernel loads firmware into device |
| */ |
| static void load_firmware(const char *firmware, const char *sysfs_path) |
| { |
| int cnt; |
| int firmware_fd, loading_fd, data_fd; |
| |
| /* check for /lib/firmware/$FIRMWARE */ |
| xchdir("/lib/firmware"); |
| firmware_fd = xopen(firmware, O_RDONLY); |
| |
| /* in case we goto out ... */ |
| data_fd = -1; |
| |
| /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */ |
| xchdir(sysfs_path); |
| for (cnt = 0; cnt < 30; ++cnt) { |
| loading_fd = open("loading", O_WRONLY); |
| if (loading_fd != -1) |
| goto loading; |
| sleep(1); |
| } |
| goto out; |
| |
| loading: |
| /* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */ |
| if (full_write(loading_fd, "1", 1) != 1) |
| goto out; |
| |
| /* load firmware into /sys/$DEVPATH/data */ |
| data_fd = open("data", O_WRONLY); |
| if (data_fd == -1) |
| goto out; |
| cnt = bb_copyfd_eof(firmware_fd, data_fd); |
| |
| /* tell kernel result by "echo [0|-1] > /sys/$DEVPATH/loading" */ |
| if (cnt > 0) |
| full_write(loading_fd, "0", 1); |
| else |
| full_write(loading_fd, "-1", 2); |
| |
| out: |
| if (ENABLE_FEATURE_CLEAN_UP) { |
| close(firmware_fd); |
| close(loading_fd); |
| close(data_fd); |
| } |
| } |
| |
| int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int mdev_main(int argc UNUSED_PARAM, char **argv) |
| { |
| RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE); |
| |
| /* We can be called as hotplug helper */ |
| /* Kernel cannot provide suitable stdio fds for us, do it ourself */ |
| bb_sanitize_stdio(); |
| |
| /* Force the configuration file settings exactly */ |
| umask(0); |
| |
| xchdir("/dev"); |
| |
| if (argv[1] && strcmp(argv[1], "-s") == 0) { |
| /* Scan: |
| * mdev -s |
| */ |
| struct stat st; |
| |
| xstat("/", &st); |
| G.root_major = major(st.st_dev); |
| G.root_minor = minor(st.st_dev); |
| |
| /* ACTION_FOLLOWLINKS is needed since in newer kernels |
| * /sys/block/loop* (for example) are symlinks to dirs, |
| * not real directories. |
| * (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs, |
| * but we can't enforce that on users) |
| */ |
| if (access("/sys/class/block", F_OK) != 0) { |
| /* Scan obsolete /sys/block only if /sys/class/block |
| * doesn't exist. Otherwise we'll have dupes. |
| * Also, do not complain if it doesn't exist. |
| * Some people configure kernel to have no blockdevs. |
| */ |
| recursive_action("/sys/block", |
| ACTION_RECURSE | ACTION_FOLLOWLINKS | ACTION_QUIET, |
| fileAction, dirAction, temp, 0); |
| } |
| recursive_action("/sys/class", |
| ACTION_RECURSE | ACTION_FOLLOWLINKS, |
| fileAction, dirAction, temp, 0); |
| } else { |
| char *fw; |
| char *seq; |
| char *action; |
| char *env_path; |
| static const char keywords[] ALIGN1 = "remove\0add\0"; |
| enum { OP_remove = 0, OP_add }; |
| smalluint op; |
| |
| /* Hotplug: |
| * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev |
| * ACTION can be "add" or "remove" |
| * DEVPATH is like "/block/sda" or "/class/input/mice" |
| */ |
| action = getenv("ACTION"); |
| env_path = getenv("DEVPATH"); |
| G.subsystem = getenv("SUBSYSTEM"); |
| if (!action || !env_path /*|| !G.subsystem*/) |
| bb_show_usage(); |
| fw = getenv("FIRMWARE"); |
| op = index_in_strings(keywords, action); |
| /* If it exists, does /dev/mdev.seq match $SEQNUM? |
| * If it does not match, earlier mdev is running |
| * in parallel, and we need to wait */ |
| seq = getenv("SEQNUM"); |
| if (seq) { |
| int timeout = 2000 / 32; /* 2000 msec */ |
| do { |
| int seqlen; |
| char seqbuf[sizeof(int)*3 + 2]; |
| |
| seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf-1)); |
| if (seqlen < 0) { |
| seq = NULL; |
| break; |
| } |
| seqbuf[seqlen] = '\0'; |
| if (seqbuf[0] == '\n' /* seed file? */ |
| || strcmp(seq, seqbuf) == 0 /* correct idx? */ |
| ) { |
| break; |
| } |
| usleep(32*1000); |
| } while (--timeout); |
| } |
| |
| snprintf(temp, PATH_MAX, "/sys%s", env_path); |
| if (op == OP_remove) { |
| /* Ignoring "remove firmware". It was reported |
| * to happen and to cause erroneous deletion |
| * of device nodes. */ |
| if (!fw) |
| make_device(temp, /*delete:*/ 1); |
| } |
| else if (op == OP_add) { |
| make_device(temp, /*delete:*/ 0); |
| if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) { |
| if (fw) |
| load_firmware(fw, temp); |
| } |
| } |
| |
| if (seq) { |
| xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1)); |
| } |
| } |
| |
| if (ENABLE_FEATURE_CLEAN_UP) |
| RELEASE_CONFIG_BUFFER(temp); |
| |
| return EXIT_SUCCESS; |
| } |