/* 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 = fdlength(fd); 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); // Dear gcc: shut up about ignoring the return value here. If it doesn't // work, what exactly are we supposed to do about it? if (CFG_MDEV_CONF) mode=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 }