| /* vi:set ts=4: |
| * |
| * mdev - Mini udev for busybox |
| * |
| * Copyright 2005, 2007 Rob Landley <rob@landley.net> |
| * Copyright 2005 Frank Sorenson <frank@tuxrocks.com> |
| * |
| * Not in SUSv3. |
| |
| USE_MDEV(NEWTOY(mdev, "s", TOYFLAG_USR|TOYFLAG_BIN)) |
| |
| config MDEV |
| bool "mdev" |
| default n |
| 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 n |
| 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 = path+strlen(path); |
| strcpy(temp, "/dev"); |
| 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); |
| umask(0); |
| if (mknod(temp, mode | type, makedev(major, minor)) && errno != EEXIST) |
| perror_exit("mknod %s failed", temp); |
| |
| if (CFG_MDEV_CONF) chown(temp, uid, gid); |
| } |
| |
| // Recursive search of /sys/block or /sys/class. path must be a writeable |
| // buffer of size PATH_MAX containing the directory string to start at. |
| |
| static void find_dev(char *path) |
| { |
| DIR *dir; |
| int len=strlen(path); |
| |
| if (!(dir = opendir(path))) |
| perror_exit("No %s",path); |
| |
| for (;;) { |
| struct dirent *entry = readdir(dir); |
| |
| if (!entry) break; |
| |
| // Skip "." and ".." (also skips hidden files, which is ok) |
| |
| if (entry->d_name[0]=='.') continue; |
| |
| if (entry->d_type == DT_DIR) { |
| snprintf(path+len, sizeof(toybuf)-len, "/%s", entry->d_name); |
| find_dev(path); |
| path[len] = 0; |
| } |
| |
| // If there's a dev entry, mknod it |
| |
| if (strcmp(entry->d_name, "dev")) make_device(path); |
| } |
| |
| closedir(dir); |
| } |
| |
| void mdev_main(void) |
| { |
| if (toys.optflags) { |
| strcpy(toybuf, "/sys/block"); |
| find_dev(toybuf); |
| strcpy(toybuf, "/sys/class"); |
| find_dev(toybuf); |
| return; |
| } |
| |
| // hotplug support goes here |
| } |