/* vi:set ts=4:

 *

 * mdev - Mini udev for busybox

 *

 * Copyright 2005, 2008 Rob Landley <rob@landley.net>

 * Copyright 2005 Frank Sorenson <frank@tuxrocks.com>

 *

 * Not in SUSv3.

USE_MDEV(NEWTOY(mdev, "s", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_UMASK))

config MDEV

	bool "mdev"

	default y

	help

	  usage: mdev [-s]

	  Create devices in /dev using information from /sys.

	  -s	Scan all entries in /sys to populate /dev.

config MDEV_CONF

	bool "Configuration file for mdev"

	default y

	depends on MDEV

	help

	  The mdev config file (/etc/mdev.conf) contains lines that look like:

		hd[a-z][0-9]* 0:3 660

	  Each line must contain three whitespace separated fields.  The first

	  field is a regular expression matching one or more device names, and

	  the second and third fields are uid:gid and file permissions for

	  matching devies.

*/

#include "toys.h"

#include "lib/xregcomp.h"

// mknod in /dev based on a path like "/sys/block/hda/hda1"

static void make_device(char *path)

{

	char *device_name, *s, *temp;

	int major, minor, type, len, fd;

	int mode = 0660;

	uid_t uid = 0;

	gid_t gid = 0;

	// Try to read major/minor string

	temp = strrchr(path, '/');

	fd = open(path, O_RDONLY);

	*temp=0;

	temp++;

	len = read(fd, temp, 64);

	close(fd);

	if (len<1) return;

	temp[len] = 0;

	// Determine device name, type, major and minor

	device_name = strrchr(path, '/') + 1;

	type = path[5]=='c' ? S_IFCHR : S_IFBLK;

	major = minor = 0;

	sscanf(temp, "%u:%u", &major, &minor);

	// If we have a config file, look up permissions for this device

	if (CFG_MDEV_CONF) {

		char *conf, *pos, *end;

		// mmap the config file

		if (-1!=(fd = open("/etc/mdev.conf", O_RDONLY))) {

			len = lseek(fd, 0, SEEK_END);

			conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);

			if (conf) {

				int line = 0;

				// Loop through lines in mmaped file

				for (pos = conf; pos-conf<len;) {

					int field;

					char *end2;

					line++;

					// find end of this line

					for(end = pos; end-conf<len && *end!='\n'; end++);

					// Three fields: regex, uid:gid, mode

					for (field = 3; field; field--) {

						// Skip whitespace

						while (pos<end && isspace(*pos)) pos++;

						if (pos==end || *pos=='#') break;

						for (end2 = pos;

							end2<end && !isspace(*end2) && *end2!='#'; end2++);

						switch(field) {

							// Regex to match this device

							case 3:

							{

								char *regex = strndupa(pos, end2-pos);

								regex_t match;

								regmatch_t off;

								int result;

								// Is this it?

								xregcomp(&match, regex, 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 end_line;

								break;

							}

							// uid:gid

							case 2:

							{

								char *s2;

								// Find :

								for(s = pos; s<end2 && *s!=':'; s++);

								if (s==end2) goto end_line;

								// Parse UID

								uid = strtoul(pos,&s2,10);

								if (s!=s2) {

									struct passwd *pass;

									pass = getpwnam(strndupa(pos, s-pos));

									if (!pass) goto end_line;

									uid = pass->pw_uid;

								}

								s++;

								// parse GID

								gid = strtoul(s,&s2,10);

								if (end2!=s2) {

									struct group *grp;

									grp = getgrnam(strndupa(s, end2-s));

									if (!grp) goto end_line;

									gid = grp->gr_gid;

								}

								break;

							}

							// mode

							case 1:

							{

								mode = strtoul(pos, &pos, 8);

								if (pos!=end2) goto end_line;

								goto found_device;

							}

						}

						pos=end2;

					}

end_line:

					// Did everything parse happily?

					if (field && field!=3) error_exit("Bad line %d", line);

					// Next line

					pos = ++end;

				}

found_device:

				munmap(conf, len);

			}

			close(fd);

		}

	}

	sprintf(temp, "/dev/%s", device_name);

	if (mknod(temp, mode | type, makedev(major, minor)) && errno != EEXIST)

		perror_exit("mknod %s failed", temp);

	if (CFG_MDEV_CONF) chown(temp, uid, gid);

}

static int callback(char *path, struct dirtree *node)

{

	// Entries in /sys/class/block aren't char devices, so skip 'em.  (We'll

	// get block devices out of /sys/block.)

	if(!strcmp(node->name, "block")) return 1;

	// Does this directory have a "dev" entry in it?

	if (S_ISDIR(node->st.st_mode) || S_ISLNK(node->st.st_mode)) {

		char *dest = path+strlen(path);

		strcpy(dest, "/dev");

		if (!access(path, R_OK)) make_device(path);

		*dest = 0;

	}

	// Circa 2.6.25 the entries more than 2 deep are all either redundant

	// (mouse#, event#) or unnamed (every usb_* entry is called "device").

	return node->depth>1;

}

void mdev_main(void)

{

	// Handle -s

	if (toys.optflags) {

		xchdir("/sys/class");

		strcpy(toybuf, "/sys/class");

		dirtree_read(toybuf, NULL, callback);

		strcpy(toybuf+5, "block");

		dirtree_read(toybuf, NULL, callback);

	}

//	if (toys.optflags) {

//		strcpy(toybuf, "/sys/block");

//		find_dev(toybuf);

//		strcpy(toybuf, "/sys/class");

//		find_dev(toybuf);

//		return;

//	}

	// hotplug support goes here

}