busybox/util-linux/mdev.c

/* 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"

/* "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;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
#define root_major (G.root_major)
#define root_minor (G.root_minor)
#define subsystem  (G.subsystem )

/* 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;
	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;
		}
	}

	/* 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/"))
		type = S_IFBLK;

	/* Make path point to "subsystem/device_name" */
	if (path[5] == 'b') /* legacy /sys/block? */
		path += sizeof("/sys/") - 1;
	else
		path += sizeof("/sys/class/") - 1;

	/* 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 */
			/* mode = strtoul(tokens[2], NULL, 8); */
			bb_parse_mode(tokens[2], &mode);

			val = tokens[3];
			/* 4th field (opt): >|=alias */

			if (ENABLE_FEATURE_MDEV_RENAME && val) {
				aliaslink = val[0];
				if (aliaslink == '>' || aliaslink == '=') {
					char *a, *s, *st;
					char *p;
					unsigned i, n;

					a = val;
					s = strchrnul(val, ' ');
					st = strchrnul(val, '\t');
					if (st < s)
						s = st;
					val = (s[0] && s[1]) ? s+1 : NULL;
					s[0] = '\0';

					if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) {
						/* 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)
					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 == root_major && minor == 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", subsystem);
				putenv(s);
				putenv(s1);
				if (system(command) == -1)
					bb_perror_msg("can't run '%s'", command);
				unsetenv("SUBSYSTEM");
				free(s1);
				unsetenv("MDEV");
				free(s);
				free(command);
			}

			if (delete) {
				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);
}

/* 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, 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(subsystem);
		subsystem = strrchr(fileName, '/');
		if (subsystem)
			subsystem = xstrdup(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);
		root_major = major(st.st_dev);
		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");
		subsystem = getenv("SUBSYSTEM");
		if (!action || !env_path /*|| !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, 1);
		}
		else if (op == OP_add) {
			make_device(temp, 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;
}
1	niro	532	/* vi: set sw=4 ts=4: */
2			/*
3			* mdev - Mini udev for busybox
4			*
5			* Copyright 2005 Rob Landley <rob@landley.net>
6			* Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
7			*
8			* Licensed under GPL version 2, see file LICENSE in this tarball for details.
9			*/
10	niro	816	#include "libbb.h"
11	niro	532	#include "xregex.h"
12
13	niro	984	/* "mdev -s" scans /sys/class/xxx, looking for directories which have dev
14			* file (it is of the form "M:m\n"). Example: /sys/class/tty/tty0/dev
15			* contains "4:0\n". Directory name is taken as device name, path component
16			* directly after /sys/class/ as subsystem. In this example, "tty0" and "tty".
17			* Then mdev creates the /dev/device_name node.
18			* If /sys/class/.../dev file does not exist, mdev still may act
19			* on this device: see "@\|$\|*command args..." parameter in config file.
20			*
21			* mdev w/o parameters is called as hotplug helper. It takes device
22			* and subsystem names from $DEVPATH and $SUBSYSTEM, extracts
23			* maj,min from "/sys/$DEVPATH/dev" and also examines
24			* $ACTION ("add"/"delete") and $FIRMWARE.
25			*
26			* If action is "add", mdev creates /dev/device_name similarly to mdev -s.
27			* (todo: explain "delete" and $FIRMWARE)
28			*
29			* If /etc/mdev.conf exists, it may modify /dev/device_name's properties.
30			* /etc/mdev.conf file format:
31			*
32			* [-][subsystem/]device user:grp mode [>\|=path] [@\|$\|*command args...]
33			* [-]@maj,min[-min2] user:grp mode [>\|=path] [@\|$\|*command args...]
34			* [-]$envvar=val user:grp mode [>\|=path] [@\|$\|*command args...]
35			*
36			* Leading minus in 1st field means "don't stop on this line", otherwise
37			* search is stopped after the matching line is encountered.
38			*
39			* The device name or "subsystem/device" combo is matched against 1st field
40			* (which is a regex), or maj,min is matched against 1st field,
41			* or specified environment variable (as regex) is matched against 1st field.
42			*
43			* $envvar=val format is useful for loading modules for hot-plugged devices
44			* which do not have driver loaded yet. In this case /sys/class/.../dev
45			* does not exist, but $MODALIAS is set to needed module's name
46			* (actually, an alias to it) by kernel. This rule instructs mdev
47			* to load the module and exit:
48			* $MODALIAS=.* 0:0 660 @modprobe "$MODALIAS"
49			* The kernel will generate another hotplug event when /sys/class/.../dev
50			* file appears.
51			*
52			* When line matches, the device node is created, chmod'ed and chown'ed,
53			* moved to path, and if >path, a symlink to moved node is created,
54			* all this if /sys/class/.../dev exists.
55			* Examples:
56			* =loop/ - moves to /dev/loop
57			* >disk/sda%1 - moves to /dev/disk/sdaN, makes /dev/sdaN a symlink
58			*
59			* Then "command args..." is executed (via sh -c 'command args...').
60			* @:execute on creation, $:on deletion, *:on both.
61			* This happens regardless of /sys/class/.../dev existence.
62			*/
63
64	niro	816	struct globals {
65			int root_major, root_minor;
66	niro	984	char *subsystem;
67	niro	816	};
68			#define G ((struct globals)&bb_common_bufsiz1)
69			#define root_major (G.root_major)
70			#define root_minor (G.root_minor)
71	niro	984	#define subsystem (G.subsystem )
72	niro	532
73	niro	816	/* Prevent infinite loops in /sys symlinks */
74			#define MAX_SYSFS_DEPTH 3
75
76			/* We use additional 64+ bytes in make_device() */
77			#define SCRATCH_SIZE 80
78
79			/* Builds an alias path.
80			* This function potentionally reallocates the alias parameter.
81	niro	984	* Only used for ENABLE_FEATURE_MDEV_RENAME
82	niro	816	*/
83			static char build_alias(char alias, const char *device_name)
84	niro	532	{
85	niro	816	char *dest;
86	niro	532
87	niro	816	/* ">bar/": rename to bar/device_name */
88			/* ">bar[/]baz": rename to bar[/]baz */
89			dest = strrchr(alias, '/');
90			if (dest) { /* ">bar/[baz]" ? */
91			dest = '\0'; / mkdir bar */
92			bb_make_directory(alias, 0755, FILEUTILS_RECUR);
93			*dest = '/';
94			if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
95			dest = alias;
96			alias = concat_path_file(alias, device_name);
97			free(dest);
98			}
99			}
100	niro	532
101	niro	816	return alias;
102			}
103
104	niro	984	/* mknod in /dev based on a path like "/sys/block/hda/hda1"
105			* NB1: path parameter needs to have SCRATCH_SIZE scratch bytes
106			* after NUL, but we promise to not mangle (IOW: to restore if needed)
107			* path string.
108			* NB2: "mdev -s" may call us many times, do not leak memory/fds!
109			*/
110	niro	532	static void make_device(char *path, int delete)
111			{
112	niro	984	char *device_name;
113	niro	532	int major, minor, type, len;
114	niro	984	mode_t mode;
115	niro	816	parser_t *parser;
116	niro	532
117			/* Try to read major/minor string. Note that the kernel puts \n after
118			* the data, so we don't need to worry about null terminating the string
119	niro	816	* because sscanf() will stop at the first nondigit, which \n is.
120			* We also depend on path having writeable space after it.
121			*/
122			major = -1;
123	niro	532	if (!delete) {
124	niro	984	char *dev_maj_min = path + strlen(path);
125
126	niro	816	strcpy(dev_maj_min, "/dev");
127			len = open_read_close(path, dev_maj_min + 1, 64);
128	niro	984	*dev_maj_min = '\0';
129	niro	816	if (len < 1) {
130			if (!ENABLE_FEATURE_MDEV_EXEC)
131			return;
132	niro	984	/* no "dev" file, but we can still run scripts
133			* based on device name */
134			} else if (sscanf(++dev_maj_min, "%u:%u", &major, &minor) != 2) {
135	niro	816	major = -1;
136			}
137	niro	532	}
138
139			/* Determine device name, type, major and minor */
140	niro	984	device_name = (char*) bb_basename(path);
141	niro	816	/* http://kernel.org/doc/pending/hotplug.txt says that only
142			* "/sys/block/..." is for block devices. "/sys/bus" etc is not.
143	niro	984	* But since 2.6.25 block devices are also in /sys/class/block,
144			* we use strstr("/block/") to forestall future surprises. */
145	niro	816	type = S_IFCHR;
146			if (strstr(path, "/block/"))
147			type = S_IFBLK;
148	niro	532
149	niro	984	/* Make path point to "subsystem/device_name" */
150			if (path[5] == 'b') /* legacy /sys/block? */
151			path += sizeof("/sys/") - 1;
152			else
153			path += sizeof("/sys/class/") - 1;
154	niro	532
155	niro	816	/* If we have config file, look up user settings */
156	niro	984	if (ENABLE_FEATURE_MDEV_CONF)
157			parser = config_open2("/etc/mdev.conf", fopen_for_read);
158	niro	532
159	niro	984	do {
160			int keep_matching;
161			struct bb_uidgid_t ugid;
162			char *tokens[4];
163			char *command = NULL;
164			char *alias = NULL;
165			char aliaslink = aliaslink; /* for compiler */
166	niro	532
167	niro	984	/* Defaults in case we won't match any line */
168			ugid.uid = ugid.gid = 0;
169			keep_matching = 0;
170			mode = 0660;
171
172			if (ENABLE_FEATURE_MDEV_CONF
173			&& config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)
174			) {
175			char *val;
176			char *str_to_match;
177			regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP];
178
179			val = tokens[0];
180			keep_matching = ('-' == val[0]);
181			val += keep_matching; /* swallow leading dash */
182
183			/* Match against either "subsystem/device_name"
184			* or "device_name" alone */
185			str_to_match = strchr(val, '/') ? path : device_name;
186
187			/* Fields: regex uid:gid mode [alias] [cmd] */
188
189			if (val[0] == '@') {
190			/* @major,minor[-minor2] */
191			/* (useful when name is ambiguous:
192			* "/sys/class/usb/lp0" and
193			* "/sys/class/printer/lp0") */
194			int cmaj, cmin0, cmin1, sc;
195			if (major < 0)
196			continue; /* no dev, no match */
197			sc = sscanf(val, "@%u,%u-%u", &cmaj, &cmin0, &cmin1);
198			if (sc < 1 \|\| major != cmaj
199			\|\| (sc == 2 && minor != cmin0)
200			\|\| (sc == 3 && (minor < cmin0 \|\| minor > cmin1))
201			) {
202			continue; /* this line doesn't match */
203			}
204			goto line_matches;
205	niro	816	}
206	niro	984	if (val[0] == '$') {
207			/* regex to match an environment variable */
208			char *eq = strchr(++val, '=');
209			if (!eq)
210			continue;
211			*eq = '\0';
212			str_to_match = getenv(val);
213			if (!str_to_match)
214			continue;
215			str_to_match -= strlen(val) + 1;
216			*eq = '=';
217			}
218			/* else: regex to match [subsystem/]device_name */
219	niro	532
220	niro	984	{
221			regex_t match;
222			int result;
223	niro	532
224	niro	984	xregcomp(&match, val, REG_EXTENDED);
225			result = regexec(&match, str_to_match, ARRAY_SIZE(off), off, 0);
226			regfree(&match);
227			//bb_error_msg("matches:");
228			//for (int i = 0; i < ARRAY_SIZE(off); i++) {
229			// if (off[i].rm_so < 0) continue;
230			// bb_error_msg("match %d: '%.*s'\n", i,
231			// (int)(off[i].rm_eo - off[i].rm_so),
232			// device_name + off[i].rm_so);
233			//}
234	niro	532
235	niro	984	/* If no match, skip rest of line */
236			/* (regexec returns whole pattern as "range" 0) */
237			if (result \|\| off[0].rm_so
238			\|\| ((int)off[0].rm_eo != (int)strlen(str_to_match))
239			) {
240			continue; /* this line doesn't match */
241			}
242	niro	816	}
243	niro	984	line_matches:
244			/* This line matches. Stop parsing after parsing
245			* the rest the line unless keep_matching == 1 */
246	niro	532
247	niro	984	/* 2nd field: uid:gid - device ownership */
248			if (get_uidgid(&ugid, tokens[1], 1) == 0)
249			bb_error_msg("unknown user/group %s on line %d", tokens[1], parser->lineno);
250	niro	532
251	niro	984	/* 3rd field: mode - device permissions */
252			/* mode = strtoul(tokens[2], NULL, 8); */
253			bb_parse_mode(tokens[2], &mode);
254	niro	532
255	niro	984	val = tokens[3];
256			/* 4th field (opt): >\|=alias */
257	niro	532
258	niro	984	if (ENABLE_FEATURE_MDEV_RENAME && val) {
259			aliaslink = val[0];
260			if (aliaslink == '>' \|\| aliaslink == '=') {
261			char a, s, *st;
262			char *p;
263			unsigned i, n;
264	niro	532
265	niro	984	a = val;
266			s = strchrnul(val, ' ');
267			st = strchrnul(val, '\t');
268			if (st < s)
269			s = st;
270			val = (s[0] && s[1]) ? s+1 : NULL;
271			s[0] = '\0';
272
273			if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) {
274			/* substitute %1..9 with off[1..9], if any */
275			n = 0;
276			s = a;
277			while (*s)
278			if (*s++ == '%')
279			n++;
280
281			p = alias = xzalloc(strlen(a) + n * strlen(str_to_match));
282			s = a + 1;
283			while (*s) {
284			p = s;
285			if ('%' == *s) {
286			i = (s[1] - '0');
287			if (i <= 9 && off[i].rm_so >= 0) {
288			n = off[i].rm_eo - off[i].rm_so;
289			strncpy(p, str_to_match + off[i].rm_so, n);
290			p += n - 1;
291			s++;
292			}
293			}
294			p++;
295			s++;
296			}
297			} else {
298			alias = xstrdup(a + 1);
299	niro	532	}
300			}
301	niro	816	}
302	niro	532
303	niro	984	if (ENABLE_FEATURE_MDEV_EXEC && val) {
304			const char s = "$@";
305			const char *s2 = strchr(s, val[0]);
306	niro	532
307	niro	984	if (!s2) {
308			bb_error_msg("bad line %u", parser->lineno);
309			if (ENABLE_FEATURE_MDEV_RENAME)
310			free(alias);
311			continue;
312			}
313	niro	816
314	niro	984	/* Are we running this command now?
315			* Run $cmd on delete, @cmd on create, *cmd on both
316			*/
317			if (s2-s != delete)
318			command = xstrdup(val + 1);
319	niro	532	}
320	niro	816	}
321	niro	532
322	niro	984	/* End of field parsing */
323	niro	532
324	niro	984	/* "Execute" the line we found */
325			{
326			const char *node_name;
327	niro	532
328	niro	984	node_name = device_name;
329			if (ENABLE_FEATURE_MDEV_RENAME && alias)
330			node_name = alias = build_alias(alias, device_name);
331	niro	532
332	niro	984	if (!delete && major >= 0) {
333			if (mknod(node_name, mode \| type, makedev(major, minor)) && errno != EEXIST)
334			bb_perror_msg("can't create %s", node_name);
335			if (major == root_major && minor == root_minor)
336			symlink(node_name, "root");
337			if (ENABLE_FEATURE_MDEV_CONF) {
338			chmod(node_name, mode);
339			chown(node_name, ugid.uid, ugid.gid);
340			}
341			if (ENABLE_FEATURE_MDEV_RENAME && alias) {
342			if (aliaslink == '>')
343			symlink(node_name, device_name);
344			}
345			}
346	niro	532
347	niro	984	if (ENABLE_FEATURE_MDEV_EXEC && command) {
348			/* setenv will leak memory, use putenv/unsetenv/free */
349			char *s = xasprintf("%s=%s", "MDEV", node_name);
350			char *s1 = xasprintf("%s=%s", "SUBSYSTEM", subsystem);
351			putenv(s);
352			putenv(s1);
353			if (system(command) == -1)
354			bb_perror_msg("can't run '%s'", command);
355			unsetenv("SUBSYSTEM");
356			free(s1);
357			unsetenv("MDEV");
358			free(s);
359			free(command);
360			}
361	niro	532
362	niro	984	if (delete) {
363			if (ENABLE_FEATURE_MDEV_RENAME && alias) {
364			if (aliaslink == '>')
365			unlink(device_name);
366			}
367			unlink(node_name);
368			}
369	niro	816
370	niro	984	if (ENABLE_FEATURE_MDEV_RENAME)
371			free(alias);
372			}
373	niro	816
374	niro	984	/* We found matching line.
375			* Stop unless it was prefixed with '-' */
376			if (ENABLE_FEATURE_MDEV_CONF && !keep_matching)
377			break;
378	niro	816
379	niro	984	/* end of "while line is read from /etc/mdev.conf" */
380			} while (ENABLE_FEATURE_MDEV_CONF);
381	niro	816
382	niro	984	if (ENABLE_FEATURE_MDEV_CONF)
383			config_close(parser);
384	niro	532	}
385
386	niro	816	/* File callback for /sys/ traversal */
387			static int FAST_FUNC fileAction(const char *fileName,
388			struct stat *statbuf UNUSED_PARAM,
389			void *userData,
390			int depth UNUSED_PARAM)
391			{
392			size_t len = strlen(fileName) - 4; /* can't underflow */
393			char *scratch = userData;
394	niro	532
395	niro	816	/* len check is for paranoid reasons */
396			if (strcmp(fileName + len, "/dev") != 0 \|\| len >= PATH_MAX)
397			return FALSE;
398
399			strcpy(scratch, fileName);
400			scratch[len] = '\0';
401			make_device(scratch, 0);
402
403			return TRUE;
404			}
405
406			/* Directory callback for /sys/ traversal */
407			static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
408			struct stat *statbuf UNUSED_PARAM,
409			void *userData UNUSED_PARAM,
410			int depth)
411	niro	532	{
412	niro	984	/* Extract device subsystem -- the name of the directory
413			* under /sys/class/ */
414			if (1 == depth) {
415			free(subsystem);
416			subsystem = strrchr(fileName, '/');
417			if (subsystem)
418			subsystem = xstrdup(subsystem + 1);
419			}
420
421	niro	816	return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
422			}
423	niro	532
424	niro	816	/* For the full gory details, see linux/Documentation/firmware_class/README
425			*
426			* Firmware loading works like this:
427			* - kernel sets FIRMWARE env var
428			* - userspace checks /lib/firmware/$FIRMWARE
429			* - userspace waits for /sys/$DEVPATH/loading to appear
430			* - userspace writes "1" to /sys/$DEVPATH/loading
431			* - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
432			* - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
433			* - kernel loads firmware into device
434			*/
435	niro	984	static void load_firmware(const char firmware, const char sysfs_path)
436	niro	816	{
437			int cnt;
438			int firmware_fd, loading_fd, data_fd;
439	niro	532
440	niro	816	/* check for /lib/firmware/$FIRMWARE */
441			xchdir("/lib/firmware");
442			firmware_fd = xopen(firmware, O_RDONLY);
443	niro	532
444	niro	816	/* in case we goto out ... */
445			data_fd = -1;
446	niro	532
447	niro	816	/* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
448			xchdir(sysfs_path);
449			for (cnt = 0; cnt < 30; ++cnt) {
450			loading_fd = open("loading", O_WRONLY);
451			if (loading_fd != -1)
452			goto loading;
453			sleep(1);
454			}
455			goto out;
456	niro	532
457	niro	816	loading:
458	niro	984	/* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */
459	niro	816	if (full_write(loading_fd, "1", 1) != 1)
460			goto out;
461	niro	532
462	niro	984	/* load firmware into /sys/$DEVPATH/data */
463	niro	816	data_fd = open("data", O_WRONLY);
464			if (data_fd == -1)
465			goto out;
466			cnt = bb_copyfd_eof(firmware_fd, data_fd);
467	niro	532
468	niro	984	/* tell kernel result by "echo [0\|-1] > /sys/$DEVPATH/loading" */
469	niro	816	if (cnt > 0)
470			full_write(loading_fd, "0", 1);
471			else
472			full_write(loading_fd, "-1", 2);
473	niro	532
474	niro	816	out:
475			if (ENABLE_FEATURE_CLEAN_UP) {
476			close(firmware_fd);
477			close(loading_fd);
478			close(data_fd);
479	niro	532	}
480			}
481
482	niro	816	int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
483			int mdev_main(int argc UNUSED_PARAM, char **argv)
484	niro	532	{
485	niro	816	RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
486	niro	532
487	niro	816	/* We can be called as hotplug helper */
488			/* Kernel cannot provide suitable stdio fds for us, do it ourself */
489			bb_sanitize_stdio();
490	niro	532
491	niro	984	/* Force the configuration file settings exactly */
492			umask(0);
493
494	niro	816	xchdir("/dev");
495	niro	532
496	niro	984	if (argv[1] && strcmp(argv[1], "-s") == 0) {
497	niro	816	/* Scan:
498			* mdev -s
499			*/
500	niro	532	struct stat st;
501
502			xstat("/", &st);
503	niro	816	root_major = major(st.st_dev);
504			root_minor = minor(st.st_dev);
505	niro	532
506	niro	816	/* ACTION_FOLLOWLINKS is needed since in newer kernels
507			* /sys/block/loop* (for example) are symlinks to dirs,
508			* not real directories.
509			* (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
510	niro	984	* but we can't enforce that on users)
511			*/
512			if (access("/sys/class/block", F_OK) != 0) {
513			/* Scan obsolete /sys/block only if /sys/class/block
514			* doesn't exist. Otherwise we'll have dupes.
515			* Also, do not complain if it doesn't exist.
516			* Some people configure kernel to have no blockdevs.
517			*/
518			recursive_action("/sys/block",
519			ACTION_RECURSE \| ACTION_FOLLOWLINKS \| ACTION_QUIET,
520			fileAction, dirAction, temp, 0);
521			}
522	niro	816	recursive_action("/sys/class",
523			ACTION_RECURSE \| ACTION_FOLLOWLINKS,
524			fileAction, dirAction, temp, 0);
525			} else {
526	niro	984	char *fw;
527	niro	816	char *seq;
528			char *action;
529			char *env_path;
530	niro	984	static const char keywords[] ALIGN1 = "remove\0add\0";
531			enum { OP_remove = 0, OP_add };
532			smalluint op;
533	niro	532
534	niro	816	/* Hotplug:
535	niro	984	* env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
536	niro	816	* ACTION can be "add" or "remove"
537			* DEVPATH is like "/block/sda" or "/class/input/mice"
538			*/
539	niro	532	action = getenv("ACTION");
540			env_path = getenv("DEVPATH");
541	niro	984	subsystem = getenv("SUBSYSTEM");
542			if (!action \|\| !env_path /\|\| !subsystem/)
543	niro	532	bb_show_usage();
544	niro	984	fw = getenv("FIRMWARE");
545			op = index_in_strings(keywords, action);
546			/* If it exists, does /dev/mdev.seq match $SEQNUM?
547			* If it does not match, earlier mdev is running
548			* in parallel, and we need to wait */
549	niro	816	seq = getenv("SEQNUM");
550			if (seq) {
551	niro	984	int timeout = 2000 / 32; /* 2000 msec */
552	niro	816	do {
553	niro	984	int seqlen;
554			char seqbuf[sizeof(int)*3 + 2];
555
556	niro	816	seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf-1));
557	niro	984	if (seqlen < 0) {
558			seq = NULL;
559	niro	816	break;
560	niro	984	}
561	niro	816	seqbuf[seqlen] = '\0';
562			if (seqbuf[0] == '\n' /* seed file? */
563			\|\| strcmp(seq, seqbuf) == 0 /* correct idx? */
564			) {
565			break;
566			}
567			usleep(32*1000);
568			} while (--timeout);
569			}
570
571			snprintf(temp, PATH_MAX, "/sys%s", env_path);
572	niro	984	if (op == OP_remove) {
573			/* Ignoring "remove firmware". It was reported
574			* to happen and to cause erroneous deletion
575			* of device nodes. */
576			if (!fw)
577			make_device(temp, 1);
578			}
579			else if (op == OP_add) {
580	niro	816	make_device(temp, 0);
581			if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
582			if (fw)
583			load_firmware(fw, temp);
584			}
585			}
586
587	niro	984	if (seq) {
588	niro	816	xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
589			}
590	niro	532	}
591
592	niro	816	if (ENABLE_FEATURE_CLEAN_UP)
593			RELEASE_CONFIG_BUFFER(temp);
594
595	niro	984	return EXIT_SUCCESS;
596	niro	532	}