X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=util-linux%2Fmdev.c;h=b4042c07ecaeda7bbabc2a9ad5c4707d36a13caf;hb=7c1b2b5420d4208864b8bc6e07e90792aed94981;hp=a18fc0916dd7fa8c83d2863d90b6b3cba4ea94ab;hpb=f0044c480c4da9c5818fe7a0973cd5529314d14b;p=oweals%2Fbusybox.git diff --git a/util-linux/mdev.c b/util-linux/mdev.c index a18fc0916..b4042c07e 100644 --- a/util-linux/mdev.c +++ b/util-linux/mdev.c @@ -1,6 +1,5 @@ /* vi: set sw=4 ts=4: */ /* - * * mdev - Mini udev for busybox * * Copyright 2005 Rob Landley @@ -8,252 +7,438 @@ * * Licensed under GPL version 2, see file LICENSE in this tarball for details. */ - #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) -#define root_major (G.root_major) -#define root_minor (G.root_minor) -#define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */ +/* 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" */ +/* 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) { - const char *device_name; + char *device_name, *subsystem_slash_devname; int major, minor, type, len; - int mode = 0660; - uid_t uid = 0; - gid_t gid = 0; - char *temp = path + strlen(path); - char *command = NULL; - char *alias = NULL; - - /* Force the configuration file settings exactly. */ - umask(0); + 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. + * 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) { - strcat(path, "/dev"); - len = open_read_close(path, temp + 1, 64); - *temp++ = 0; - if (len < 1) - return; + 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; + } } /* Determine device name, type, major and minor */ - device_name = bb_basename(path); - type = (path[5] == 'c' ? S_IFCHR : S_IFBLK); - - if (ENABLE_FEATURE_MDEV_CONF) { - FILE *fp; - char *line, *vline; - unsigned lineno = 0; - - /* If we have a config file, look up the user settings */ - fp = fopen_or_warn("/etc/mdev.conf", "r"); - if (!fp) - goto end_parse; - - while ((vline = line = xmalloc_getline(fp)) != NULL) { - int field; - - /* A pristine copy for command execution. */ - char *orig_line; - if (ENABLE_FEATURE_MDEV_EXEC) - orig_line = xstrdup(line); - - ++lineno; - - /* Three fields: regex, uid:gid, mode */ - for (field = 0; field < (3 + ENABLE_FEATURE_MDEV_RENAME + ENABLE_FEATURE_MDEV_EXEC); ++field) { - - /* Find a non-empty field */ - char *val; - do { - val = strtok(vline, " \t"); - vline = NULL; - } while (val && !*val); - if (!val) { - if (field) - break; - else - goto next_line; - } - - if (field == 0) { - - /* Regex to match this device */ - regex_t match; - regmatch_t off; - int result; - - /* Is this it? */ - xregcomp(&match, val, REG_EXTENDED); - result = regexec(&match, device_name, 1, &off, 0); - regfree(&match); - - /* If not this device, skip rest of line */ - if (result || off.rm_so || off.rm_eo != strlen(device_name)) - goto next_line; - - } else if (field == 1) { - - /* uid:gid device ownership */ - struct passwd *pass; - struct group *grp; - - char *str_uid = val; - char *str_gid = strchr(val, ':'); - if (str_gid) - *str_gid = '\0', ++str_gid; - - /* Parse UID */ - pass = getpwnam(str_uid); - if (pass) - uid = pass->pw_uid; - else - uid = strtoul(str_uid, NULL, 10); - - /* parse GID */ - grp = getgrnam(str_gid); - if (grp) - gid = grp->gr_gid; - else - gid = strtoul(str_gid, NULL, 10); - - } else if (field == 2) { - - /* Mode device permissions */ - mode = strtoul(val, NULL, 8); - - } else if (ENABLE_FEATURE_MDEV_RENAME && field == 3) { - - if (*val != '>') - ++field; - else - alias = xstrdup(val + 1); + 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 = -1; + } + 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 && field == 3 + ENABLE_FEATURE_MDEV_RENAME) { - - /* Optional command to run */ - const char *s = "@$*"; - const char *s2 = strchr(s, *val); + if (ENABLE_FEATURE_MDEV_EXEC && val) { + const char *s = "$@*"; + const char *s2 = strchr(s, val[0]); - if (!s2) { - /* Force error */ - field = 1; - break; - } + if (!s2) { + bb_error_msg("bad line %u", parser->lineno); + if (ENABLE_FEATURE_MDEV_RENAME) + free(alias); + continue; + } - /* Correlate the position in the "@$*" with the delete - * step so that we get the proper behavior. + /* 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 */ - if ((s2 - s + 1) & (1 << delete)) - command = xstrdup(orig_line + (val + 1 - line)); + command = xstrdup(val + 1); } } - - /* Did everything parse happily? */ - if (field <= 2) - bb_error_msg_and_die("bad line %u", lineno); - - next_line: - free(line); - if (ENABLE_FEATURE_MDEV_EXEC) - free(orig_line); } - if (ENABLE_FEATURE_CLEAN_UP) - fclose(fp); + /* End of field parsing */ - end_parse: /* nothing */ ; - } - - if (!delete) { - if (sscanf(temp, "%d:%d", &major, &minor) != 2) - return; + /* "Execute" the line we found */ + { + const char *node_name; - if (ENABLE_FEATURE_MDEV_RENAME) - unlink(device_name); + node_name = device_name; + if (ENABLE_FEATURE_MDEV_RENAME && alias) + node_name = alias = build_alias(alias, device_name); - if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST) - bb_perror_msg_and_die("mknod %s", 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 (major == root_major && minor == root_minor) - symlink(device_name, "root"); + 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 (ENABLE_FEATURE_MDEV_CONF) { - chown(device_name, uid, gid); + if (delete && major >= 0) { + if (ENABLE_FEATURE_MDEV_RENAME && alias) { + if (aliaslink == '>') + unlink(device_name); + } + unlink(node_name); + } - if (ENABLE_FEATURE_MDEV_RENAME && alias) { - char *dest; + if (ENABLE_FEATURE_MDEV_RENAME) + free(alias); + } - temp = strrchr(alias, '/'); - if (temp) { - if (temp[1] != '\0') - /* given a file name, so rename it */ - *temp = '\0'; - bb_make_directory(alias, 0755, FILEUTILS_RECUR); - dest = concat_path_file(alias, device_name); - } else - dest = alias; + /* We found matching line. + * Stop unless it was prefixed with '-' */ + if (ENABLE_FEATURE_MDEV_CONF && !keep_matching) + break; - rename(device_name, dest); - symlink(dest, device_name); + /* end of "while line is read from /etc/mdev.conf" */ + } while (ENABLE_FEATURE_MDEV_CONF); - if (alias != dest) - free(alias); - free(dest); - } - } - } - if (ENABLE_FEATURE_MDEV_EXEC && command) { - /* setenv will leak memory, so use putenv */ - char *s = xasprintf("MDEV=%s", device_name); - putenv(s); - if (system(command) == -1) - bb_perror_msg_and_die("cannot run %s", command); - s[4] = '\0'; - unsetenv(s); - free(s); - free(command); - } - if (delete) - remove_file(device_name, FILEUTILS_FORCE); + if (ENABLE_FEATURE_MDEV_CONF) + config_close(parser); + free(subsystem_slash_devname); } /* File callback for /sys/ traversal */ -static int fileAction(const char *fileName, struct stat *statbuf, - void *userData, int depth) +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; + size_t len = strlen(fileName) - 4; /* can't underflow */ char *scratch = userData; - if (strcmp(fileName + len, "/dev")) + /* 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, 0); + scratch[len] = '\0'; + make_device(scratch, /*delete:*/ 0); return TRUE; } /* Directory callback for /sys/ traversal */ -static int dirAction(const char *fileName, struct stat *statbuf, - void *userData, int depth) +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); } @@ -268,17 +453,11 @@ static int dirAction(const char *fileName, struct stat *statbuf, * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading * - kernel loads firmware into device */ -static void load_firmware(const char *const firmware, const char *const sysfs_path) +static void load_firmware(const char *firmware, const char *sysfs_path) { int cnt; int firmware_fd, loading_fd, data_fd; - /* check for $FIRMWARE from kernel */ - /* XXX: dont bother: open(NULL) works same as open("no-such-file") - * if (!firmware) - * return; - */ - /* check for /lib/firmware/$FIRMWARE */ xchdir("/lib/firmware"); firmware_fd = xopen(firmware, O_RDONLY); @@ -290,29 +469,28 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa xchdir(sysfs_path); for (cnt = 0; cnt < 30; ++cnt) { loading_fd = open("loading", O_WRONLY); - if (loading_fd == -1) - sleep(1); - else - break; + if (loading_fd != -1) + goto loading; + sleep(1); } - if (loading_fd == -1) - goto out; + goto out; - /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */ - if (write(loading_fd, "1", 1) != 1) + loading: + /* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */ + if (full_write(loading_fd, "1", 1) != 1) goto out; - /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */ + /* 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` */ + /* tell kernel result by "echo [0|-1] > /sys/$DEVPATH/loading" */ if (cnt > 0) - write(loading_fd, "0", 1); + full_write(loading_fd, "0", 1); else - write(loading_fd, "-1", 2); + full_write(loading_fd, "-1", 2); out: if (ENABLE_FEATURE_CLEAN_UP) { @@ -323,60 +501,117 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa } int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; -int mdev_main(int argc, char **argv) +int mdev_main(int argc UNUSED_PARAM, char **argv) { - char *action; - char *env_path; - RESERVE_CONFIG_BUFFER(temp,PATH_MAX); + RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE); - xchdir("/dev"); + /* 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); - if (argc == 2 && !strcmp(argv[1],"-s")) { + xchdir("/dev"); + if (argv[1] && strcmp(argv[1], "-s") == 0) { /* Scan: * mdev -s */ - struct stat st; xstat("/", &st); - root_major = major(st.st_dev); - root_minor = minor(st.st_dev); - - recursive_action("/sys/block", - ACTION_RECURSE | ACTION_FOLLOWLINKS, - fileAction, dirAction, temp, 0); - + 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=... mdev + * 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"); - if (!action || !env_path) + 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); + } - sprintf(temp, "/sys%s", env_path); - if (!strcmp(action, "remove")) - make_device(temp, 1); - else if (!strcmp(action, "add")) { - make_device(temp, 0); + 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 (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) - load_firmware(getenv("FIRMWARE"), temp); + if (seq) { + xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1)); } } if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp); - return 0; + return EXIT_SUCCESS; }