util-linux/mdev.c - busybox - Git at Google

 /* 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 GPL version 2, see file LICENSE in this tarball for details.
  */

 #include "libbb.h"
 #include "xregex.h"

 struct globals {
 	int root_major, root_minor;
 };
 #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 */

 /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
 static void make_device(char *path, int delete)
 {
 	const char *device_name;
 	int major, minor, type, len;
 	int mode = 0660;
 	uid_t uid = 0;
 	gid_t gid = 0;
 	char *temp = path + strlen(path);
 	char *command = NULL;

 	/* 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.
 	 */
 	if (!delete) {
 		strcat(path, "/dev");
 		len = open_read_close(path, temp + 1, 64);
 		*temp++ = 0;
 		if (len < 1)
 			return;
 	}

 	/* 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_EXEC); ++field) {

 				/* Find a non-empty field */
 				char *val;
 				do {
 					val = strtok(vline, " \t");
 					vline = NULL;
 				} while (val && !*val);
 				if (!val)
 					break;

 				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_EXEC && field == 3) {

 					/* Optional command to run */
 					const char *s = "@$*";
 					const char *s2 = strchr(s, *val);

 					if (!s2) {
 						/* Force error */
 						field = 1;
 						break;
 					}

 					/* Correlate the position in the "@$*" with the delete
 					 * step so that we get the proper behavior.
 					 */
 					if ((s2 - s + 1) & (1 << delete))
 						command = xstrdup(orig_line + (val + 1 - line));
 				}
 			}

 			/* 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_parse:	/* nothing */ ;
 	}

 	umask(0);
 	if (!delete) {
 		if (sscanf(temp, "%d:%d", &major, &minor) != 2)
 			return;
 		if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
 			bb_perror_msg_and_die("mknod %s", device_name);

 		if (major == root_major && minor == root_minor)
 			symlink(device_name, "root");

 		if (ENABLE_FEATURE_MDEV_CONF)
 			chown(device_name, uid, gid);
 	}
 	if (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);
 }

 /* File callback for /sys/ traversal */
 static int fileAction(const char *fileName, struct stat *statbuf,
                       void *userData, int depth)
 {
 	size_t len = strlen(fileName) - 4;
 	char *scratch = userData;

 	if (strcmp(fileName + len, "/dev"))
 		return FALSE;

 	strcpy(scratch, fileName);
 	scratch[len] = 0;
 	make_device(scratch, 0);

 	return TRUE;
 }

 /* Directory callback for /sys/ traversal */
 static int dirAction(const char *fileName, struct stat *statbuf,
                       void *userData, int depth)
 {
 	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 *const firmware, const char *const 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);

 	/* 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)
 			sleep(1);
 		else
 			break;
 	}
 	if (loading_fd == -1)
 		goto out;

 	/* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
 	if (write(loading_fd, "1", 1) != 1)
 		goto out;

 	/* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$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)
 		write(loading_fd, "0", 1);
 	else
 		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, char **argv)
 {
 	char *action;
 	char *env_path;
 	RESERVE_CONFIG_BUFFER(temp,PATH_MAX);

 	xchdir("/dev");

 	if (argc == 2 && !strcmp(argv[1],"-s")) {

 		/* 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);

 		recursive_action("/sys/class",
 			ACTION_RECURSE | ACTION_FOLLOWLINKS,
 			fileAction, dirAction, temp, 0);

 	} else {

 		/* Hotplug:
 		 * env ACTION=... DEVPATH=... 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)
 			bb_show_usage();

 		sprintf(temp, "/sys%s", env_path);
 		if (!strcmp(action, "remove"))
 			make_device(temp, 1);
 		else if (!strcmp(action, "add")) {
 			make_device(temp, 0);

 			if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE)
 				load_firmware(getenv("FIRMWARE"), temp);
 		}
 	}

 	if (ENABLE_FEATURE_CLEAN_UP)
 		RELEASE_CONFIG_BUFFER(temp);

 	return 0;
 }
	/* 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 GPL version 2, see file LICENSE in this tarball for details.
	*/

	#include "libbb.h"
	#include "xregex.h"

	struct globals {
	int root_major, root_minor;
	};
	#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 */

	/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
	static void make_device(char *path, int delete)
	{
	const char *device_name;
	int major, minor, type, len;
	int mode = 0660;
	uid_t uid = 0;
	gid_t gid = 0;
	char *temp = path + strlen(path);
	char *command = NULL;

	/* 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.
	*/
	if (!delete) {
	strcat(path, "/dev");
	len = open_read_close(path, temp + 1, 64);
	*temp++ = 0;
	if (len < 1)
	return;
	}

	/* 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_EXEC); ++field) {

	/* Find a non-empty field */
	char *val;
	do {
	val = strtok(vline, " \t");
	vline = NULL;
	} while (val && !*val);
	if (!val)
	break;

	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_EXEC && field == 3) {

	/* Optional command to run */
	const char s = "@$";
	const char s2 = strchr(s, val);

	if (!s2) {
	/* Force error */
	field = 1;
	break;
	}

	/* Correlate the position in the "@$*" with the delete
	* step so that we get the proper behavior.
	*/
	if ((s2 - s + 1) & (1 << delete))
	command = xstrdup(orig_line + (val + 1 - line));
	}
	}

	/* 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_parse: /* nothing */ ;
	}

	umask(0);
	if (!delete) {
	if (sscanf(temp, "%d:%d", &major, &minor) != 2)
	return;
	if (mknod(device_name, mode \| type, makedev(major, minor)) && errno != EEXIST)
	bb_perror_msg_and_die("mknod %s", device_name);

	if (major == root_major && minor == root_minor)
	symlink(device_name, "root");

	if (ENABLE_FEATURE_MDEV_CONF)
	chown(device_name, uid, gid);
	}
	if (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);
	}

	/* File callback for /sys/ traversal */
	static int fileAction(const char fileName, struct stat statbuf,
	void *userData, int depth)
	{
	size_t len = strlen(fileName) - 4;
	char *scratch = userData;

	if (strcmp(fileName + len, "/dev"))
	return FALSE;

	strcpy(scratch, fileName);
	scratch[len] = 0;
	make_device(scratch, 0);

	return TRUE;
	}

	/* Directory callback for /sys/ traversal */
	static int dirAction(const char fileName, struct stat statbuf,
	void *userData, int depth)
	{
	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 const firmware, const char const 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);

	/* 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)
	sleep(1);
	else
	break;
	}
	if (loading_fd == -1)
	goto out;

	/* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
	if (write(loading_fd, "1", 1) != 1)
	goto out;

	/* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$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)
	write(loading_fd, "0", 1);
	else
	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, char **argv)
	{
	char *action;
	char *env_path;
	RESERVE_CONFIG_BUFFER(temp,PATH_MAX);

	xchdir("/dev");

	if (argc == 2 && !strcmp(argv[1],"-s")) {

	/* 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);

	recursive_action("/sys/class",
	ACTION_RECURSE \| ACTION_FOLLOWLINKS,
	fileAction, dirAction, temp, 0);

	} else {

	/* Hotplug:
	* env ACTION=... DEVPATH=... 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)
	bb_show_usage();

	sprintf(temp, "/sys%s", env_path);
	if (!strcmp(action, "remove"))
	make_device(temp, 1);
	else if (!strcmp(action, "add")) {
	make_device(temp, 0);

	if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE)
	load_firmware(getenv("FIRMWARE"), temp);
	}
	}

	if (ENABLE_FEATURE_CLEAN_UP)
	RELEASE_CONFIG_BUFFER(temp);

	return 0;
	}