On Monday 19 September 2011 15:38, Laurent Bercot wrote: > >> mdev could also be patched to be run as a "mdevd" daemon listening > >> to the netlink. That would solve the speed problem related to > >> /etc/mdev.conf parsing, and would still be orders of magnitude below > >> the complexity of udevd. > > After closer examination of the mdev.c source code, I must say I was > wrong. As it is now, the /etc/mdev.conf file is parsed on every event. > (And it makes sense: since this file describes what to do on an event, > its natural to read it on an event.) > The only way to speed this up is to pre-parse the /etc/mdev.conf file: > compile it once into a fast access structure which can then be > interpreted on every event. This fast access structure could be stored > in memory, if we're to have a long-running "mdevd" program ; or it > could be stored as another, less user-friendly, file (for instance a > cdb file) if we're still going to have one mdev invocation per event. > > I'm not sure this is worth it - mdev -s is only run once at boot time, > and once /etc/mdev.conf is in the filesystem cache, the parsing should > be CPU-bound, which means it can be run in parallel with other > initialization tasks (that are majorly IO-bound) without a performance > loss.
I propose the following changed implementation. In "mdev -s" case it saves parsed rules as they are read, and reuses them for next devices. Config file (and its regexs) is read/parsed only once. This saves repeated rereads and re-parsing. +350 bytes: 2824 0 0 2824 b08 busybox.t2/util-linux/mdev.o 3174 0 0 3174 c66 busybox.t3/util-linux/mdev.o Please review. -- vda /* vi: set sw=4 ts=4: */ /* * mdev - Mini udev for busybox * * Copyright 2005 Rob Landley <[email protected]> * Copyright 2005 Frank Sorenson <[email protected]> * * Licensed under GPLv2, see file LICENSE in this source tree. */ //config:config MDEV //config: bool "mdev" //config: default y //config: select PLATFORM_LINUX //config: help //config: mdev is a mini-udev implementation for dynamically creating device //config: nodes in the /dev directory. //config: //config: For more information, please see docs/mdev.txt //config: //config:config FEATURE_MDEV_CONF //config: bool "Support /etc/mdev.conf" //config: default y //config: depends on MDEV //config: help //config: Add support for the mdev config file to control ownership and //config: permissions of the device nodes. //config: //config: For more information, please see docs/mdev.txt //config: //config:config FEATURE_MDEV_RENAME //config: bool "Support subdirs/symlinks" //config: default y //config: depends on FEATURE_MDEV_CONF //config: help //config: Add support for renaming devices and creating symlinks. //config: //config: For more information, please see docs/mdev.txt //config: //config:config FEATURE_MDEV_RENAME_REGEXP //config: bool "Support regular expressions substitutions when renaming device" //config: default y //config: depends on FEATURE_MDEV_RENAME //config: help //config: Add support for regular expressions substitutions when renaming //config: device. //config: //config:config FEATURE_MDEV_EXEC //config: bool "Support command execution at device addition/removal" //config: default y //config: depends on FEATURE_MDEV_CONF //config: help //config: This adds support for an optional field to /etc/mdev.conf for //config: executing commands when devices are created/removed. //config: //config: For more information, please see docs/mdev.txt //config: //config:config FEATURE_MDEV_LOAD_FIRMWARE //config: bool "Support loading of firmwares" //config: default y //config: depends on MDEV //config: help //config: Some devices need to load firmware before they can be usable. //config: //config: These devices will request userspace look up the files in //config: /lib/firmware/ and if it exists, send it to the kernel for //config: loading into the hardware. //applet:IF_MDEV(APPLET(mdev, BB_DIR_SBIN, BB_SUID_DROP)) //kbuild:lib-$(CONFIG_MDEV) += mdev.o //usage:#define mdev_trivial_usage //usage: "[-s]" //usage:#define mdev_full_usage "\n\n" //usage: "mdev -s is to be run during boot to scan /sys and populate /dev.\n" //usage: "\n" //usage: "Bare mdev is a kernel hotplug helper. To activate it:\n" //usage: " echo /sbin/mdev >/proc/sys/kernel/hotplug\n" //usage: IF_FEATURE_MDEV_CONF( //usage: "\n" //usage: "It uses /etc/mdev.conf with lines\n" //usage: " [-]DEVNAME UID:GID PERM" //usage: IF_FEATURE_MDEV_RENAME(" [>|=PATH]|[!]") //usage: IF_FEATURE_MDEV_EXEC(" [@|$|*PROG]") //usage: "\n" //usage: "where DEVNAME is device name regex, @major,minor[-minor2], or\n" //usage: "environment variable regex. A common use of the latter is\n" //usage: "to load modules for hotplugged devices:\n" //usage: " $MODALIAS=.* 0:0 660 @modprobe \"$MODALIAS\"\n" //usage: ) //usage: "\n" //usage: "If /dev/mdev.seq file exists, mdev will wait for its value\n" //usage: "to match $SEQNUM variable. This prevents plug/unplug races.\n" //usage: "To activate this feature, create empty /dev/mdev.seq at boot." //usage: //usage:#define mdev_notes_usage "" //usage: IF_FEATURE_MDEV_CONFIG( //usage: "The mdev config file contains lines that look like:\n" //usage: " hd[a-z][0-9]* 0:3 660\n\n" //usage: "That's device name (with regex match), uid:gid, and permissions.\n\n" //usage: IF_FEATURE_MDEV_EXEC( //usage: "Optionally, that can be followed (on the same line) by a special character\n" //usage: "and a command line to run after creating/before deleting the corresponding\n" //usage: "device(s). The environment variable $MDEV indicates the active device node\n" //usage: "(which is useful if it's a regex match). For example:\n\n" //usage: " hdc root:cdrom 660 *ln -s $MDEV cdrom\n\n" //usage: "The special characters are @ (run after creating), $ (run before deleting),\n" //usage: "and * (run both after creating and before deleting). The commands run in\n" //usage: "the /dev directory, and use system() which calls /bin/sh.\n\n" //usage: ) //usage: "Config file parsing stops on the first matching line. If no config\n" //usage: "entry is matched, devices are created with default 0:0 660. (Make\n" //usage: "the last line match .* to override this.)\n\n" //usage: ) #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, $:on deletion, *:on both. * This happens regardless of /sys/class/.../dev existence. */ struct rule { bool keep_matching; bool regex_compiled; bool regex_has_slash; mode_t mode; int maj, min0, min1; char *envvar; struct bb_uidgid_t ugid; char *ren_mov; char *command; regex_t match; }; struct globals { int root_major, root_minor; char *subsystem; const char *filename; parser_t *parser; #if ENABLE_FEATURE_MDEV_CONF struct rule **rule_vec; unsigned rule_idx; #endif struct rule cur_rule; } FIX_ALIASING; #define G (*(struct globals*)&bb_common_bufsiz1) #define INIT_G() do { } while (0) /* Prevent infinite loops in /sys symlinks */ #define MAX_SYSFS_DEPTH 3 /* We use additional 64+ bytes in make_device() */ #define SCRATCH_SIZE 80 #if 0 # define dbg(...) bb_error_msg(__VA_ARGS__) #else # define dbg(...) ((void)0) #endif #if ENABLE_FEATURE_MDEV_CONF static void clean_up_cur_rule(void) { free(G.cur_rule.envvar); if (G.cur_rule.regex_compiled) regfree(&G.cur_rule.match); free(G.cur_rule.ren_mov); free(G.cur_rule.command); } static struct rule *parse_next_rule(void) { char *tokens[4]; while (config_read(G.parser, tokens, 4, 3, "# \t", PARSE_NORMAL)) { char *val; memset(&G.cur_rule, 0, sizeof(G.cur_rule)); G.cur_rule.maj = -1; /* "not a @major,minor rule" */ /* Fields: [-]regex uid:gid mode [alias] [cmd] */ /* 1st field */ val = tokens[0]; G.cur_rule.keep_matching = ('-' == val[0]); val += G.cur_rule.keep_matching; /* swallow leading dash */ if (val[0] == '@') { /* @major,minor[-minor2] */ /* (useful when name is ambiguous: * "/sys/class/usb/lp0" and * "/sys/class/printer/lp0") */ int sc = sscanf(val, "@%u,%u-%u", &G.cur_rule.maj, &G.cur_rule.min0, &G.cur_rule.min1); if (sc < 2 || G.cur_rule.maj < 0) { bb_error_msg("bad @maj,min on line %d", G.parser->lineno); goto next_rule; } if (sc == 2) G.cur_rule.min1 = G.cur_rule.min0; } else { if (val[0] == '$') { char *eq = strchr(val, '='); if (!eq) { bb_error_msg("bad $envvar=regex on line %d", G.parser->lineno); goto next_rule; } G.cur_rule.envvar = xstrndup(val, eq - val); val = eq + 1; } xregcomp(&G.cur_rule.match, val, REG_EXTENDED); G.cur_rule.regex_compiled = 1; G.cur_rule.regex_has_slash = (strchr(val, '/') != NULL); } /* 2nd field: uid:gid - device ownership */ if (get_uidgid(&G.cur_rule.ugid, tokens[1], /*allow_numeric:*/ 1) == 0) { bb_error_msg("unknown user/group '%s' on line %d", tokens[1], G.parser->lineno); goto next_rule; } /* 3rd field: mode - device permissions */ bb_parse_mode(tokens[2], &G.cur_rule.mode); /* 4th field (opt): ">|=alias" or "!" to not create the node */ val = tokens[3]; if (ENABLE_FEATURE_MDEV_RENAME && val) { char *s = skip_non_whitespace(val); G.cur_rule.ren_mov = xstrndup(val, s - val); val = skip_whitespace(s); } if (ENABLE_FEATURE_MDEV_EXEC && val && val[0]) { const char *s = "$@*"; const char *s2 = strchr(s, val[0]); if (!s2) { bb_error_msg("bad line %u", G.parser->lineno); goto next_rule; } G.cur_rule.command = xstrdup(val); } return &G.cur_rule; next_rule: clean_up_cur_rule(); } /* while (config_read) */ dbg("config_close(G.parser)"); config_close(G.parser); G.parser = NULL; return NULL; } static const struct rule *next_rule(void) { struct rule *rule; /* Open conf file if necessary */ if (!G.parser && G.filename) { dbg("config_open()"); G.parser = config_open2(G.filename, fopen_for_read); G.filename = NULL; } if (G.rule_vec) { /* mdev -s? */ /* Do we have parsed rule? */ if (G.rule_vec[G.rule_idx]) { dbg("< G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]); return G.rule_vec[G.rule_idx++]; } } else { /* not mdev -s */ clean_up_cur_rule(); } /* Parse one more rule if file isn't fully read */ rule = NULL; if (G.parser) { rule = parse_next_rule(); if (rule && G.rule_vec) { /* mdev -s */ rule = memcpy(xmalloc(sizeof(*rule)), rule, sizeof(*rule)); G.rule_vec = xrealloc_vector(G.rule_vec, 4, G.rule_idx); G.rule_vec[G.rule_idx++] = rule; dbg("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]); } } return rule; } #else static const struct rule *next_rule(void) { G.cur_rule.mode = 0660; G.cur_rule.maj = -1; return &G.cur_rule; } #endif /* 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; dbg("%s('%s', delete:%d)", __func__, path, delete); /* 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; } G.rule_idx = 0; do { const char *str_to_match; int regex_match; regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP]; char *command; char *alias; char aliaslink = aliaslink; /* for compiler */ const char *node_name; const struct rule *rule; rule = next_rule(); #if ENABLE_FEATURE_MDEV_CONF if (!rule) return; if (rule->maj >= 0) { /* @maj,min rule */ if (major != rule->maj) continue; if (minor < rule->min0 || minor > rule->min1) continue; str_to_match = ""; memset(off, 0, sizeof(0)); goto line_matches; } if (rule->envvar) { /* $envvar=regex rule */ str_to_match = getenv(rule->envvar); if (!str_to_match) continue; } else { /* regex to match [subsystem/]device_name */ str_to_match = (rule->regex_has_slash ? path : device_name); } regex_match = regexec(&rule->match, str_to_match, ARRAY_SIZE(off), off, 0); //bb_error_msg("matches:"); //for (int i = 0; i < ARRAY_SIZE(off); i++) { // if (off[i].rm_so < 0) continue; // bb_error_msg("match %d: '%.*s'\n", i, // (int)(off[i].rm_eo - off[i].rm_so), // device_name + off[i].rm_so); //} /* If no match, skip rest of line */ /* (regexec returns whole pattern as "range" 0) */ if (regex_match != 0 || off[0].rm_so != 0 || (int)off[0].rm_eo != (int)strlen(str_to_match) ) { continue; /* this line doesn't match */ } #endif line_matches: /* Build alias name */ alias = NULL; if (ENABLE_FEATURE_MDEV_RENAME && rule->ren_mov) { aliaslink = rule->ren_mov[0]; if (aliaslink == '!') { /* "!": suppress node creation/deletion */ major = -2; } else if (aliaslink == '>' || aliaslink == '=') { if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) { char *s; char *p; unsigned n; /* substitute %1..9 with off[1..9], if any */ n = 0; s = rule->ren_mov; while (*s) if (*s++ == '%') n++; p = alias = xzalloc(strlen(rule->ren_mov) + n * strlen(str_to_match)); s = rule->ren_mov + 1; while (*s) { *p = *s; if ('%' == *s) { unsigned i = (s[1] - '0'); if (i <= 9 && off[i].rm_so >= 0) { n = off[i].rm_eo - off[i].rm_so; strncpy(p, str_to_match + off[i].rm_so, n); p += n - 1; s++; } } p++; s++; } } else { alias = xstrdup(rule->ren_mov + 1); } } } command = ENABLE_FEATURE_MDEV_CONF ? rule->command : NULL; if (ENABLE_FEATURE_MDEV_EXEC && command) { const char *s = "$@*"; const char *s2 = strchr(s, command[0]); /* 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++; } else { command = NULL; } } /* "Execute" the line we found */ 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, rule->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, rule->mode); chown(node_name, rule->ugid.uid, rule->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 && !rule->keep_matching) break; /* go try next rule */ } while (ENABLE_FEATURE_MDEV_CONF); 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); INIT_G(); G.filename = "/etc/mdev.conf"; /* 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; #if ENABLE_FEATURE_MDEV_CONF G.rule_vec = xrealloc_vector(NULL, 4, 0); #endif 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; } _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
