diff options
Diffstat (limited to 'util-linux/mdev.c')
-rw-r--r-- | util-linux/mdev.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/util-linux/mdev.c b/util-linux/mdev.c new file mode 100644 index 000000000..957316d52 --- /dev/null +++ b/util-linux/mdev.c @@ -0,0 +1,268 @@ +/* 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 "busybox.h" +#include "xregex.h" + +#define DEV_PATH "/dev" + +struct mdev_globals +{ + int root_major, root_minor; +} mdev_globals; + +#define bbg mdev_globals + +/* mknod in /dev based on a path like "/sys/block/hda/hda1" */ +static void make_device(char *path, int delete) +{ + 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 = strrchr(path, '/') + 1; + type = path[5]=='c' ? S_IFCHR : S_IFBLK; + + /* If we have a config file, look up permissions for this device */ + + if (ENABLE_FEATURE_MDEV_CONF) { + char *conf, *pos, *end; + int line, fd; + + /* mmap the config file */ + fd = open("/etc/mdev.conf", O_RDONLY); + if (fd < 0) + goto end_parse; + len = xlseek(fd, 0, SEEK_END); + conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); + if (!conf) + goto end_parse; + + 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=0; field < (3 + ENABLE_FEATURE_MDEV_EXEC); + field++) + { + /* Skip whitespace */ + while (pos<end && isspace(*pos)) pos++; + if (pos==end || *pos=='#') break; + for (end2=pos; + end2<end && !isspace(*end2) && *end2!='#'; end2++) + ; + + if (field == 0) { + /* Regex to match this device */ + + 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)) + break; + } + if (field == 1) { + /* uid:gid */ + + char *s, *s2; + + /* Find : */ + for (s=pos; s<end2 && *s!=':'; s++) + ; + if (s == end2) break; + + /* Parse UID */ + uid = strtoul(pos, &s2, 10); + if (s != s2) { + struct passwd *pass; + pass = getpwnam(strndupa(pos, s-pos)); + if (!pass) break; + 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) break; + gid = grp->gr_gid; + } + } + if (field == 2) { + /* mode */ + + mode = strtoul(pos, &pos, 8); + if (pos != end2) break; + } + if (ENABLE_FEATURE_MDEV_EXEC && field == 3) { + // Command to run + char *s = "@$*", *s2; + s2 = strchr(s, *pos++); + if (!s2) { + // Force error + field = 1; + break; + } + if ((s2-s+1) & (1<<delete)) + command = xstrndup(pos, end-pos); + } + + pos = end2; + } + + /* Did everything parse happily? */ + + if (field > 2) break; + if (field) bb_error_msg_and_die("bad line %d",line); + + /* Next line */ + pos = ++end; + } + munmap(conf, len); + 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 == bbg.root_major && minor == bbg.root_minor) + symlink(device_name, "root"); + + if (ENABLE_FEATURE_MDEV_CONF) chown(device_name, uid, gid); + } + if (command) { + int rc; + char *s; + + s = xasprintf("MDEV=%s", device_name); + putenv(s); + rc = system(command); + s[4] = 0; + putenv(s); + free(s); + free(command); + if (rc == -1) bb_perror_msg_and_die("cannot run %s", command); + } + if (delete) unlink(device_name); +} + +/* 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; + size_t len = strlen(path); + struct dirent *entry; + + dir = opendir(path); + if (dir == NULL) + return; + + while ((entry = readdir(dir)) != NULL) { + struct stat st; + + /* Skip "." and ".." (also skips hidden files, which is ok) */ + + if (entry->d_name[0] == '.') + continue; + + // uClibc doesn't fill out entry->d_type reliably. so we use lstat(). + + snprintf(path+len, PATH_MAX-len, "/%s", entry->d_name); + if (!lstat(path, &st) && S_ISDIR(st.st_mode)) find_dev(path); + path[len] = 0; + + /* If there's a dev entry, mknod it */ + + if (!strcmp(entry->d_name, "dev")) make_device(path, 0); + } + + closedir(dir); +} + +int mdev_main(int argc, char *argv[]) +{ + char *action; + char *env_path; + RESERVE_CONFIG_BUFFER(temp,PATH_MAX); + + xchdir(DEV_PATH); + + /* Scan */ + + if (argc == 2 && !strcmp(argv[1],"-s")) { + struct stat st; + + xstat("/", &st); + bbg.root_major = major(st.st_dev); + bbg.root_minor = minor(st.st_dev); + strcpy(temp,"/sys/block"); + find_dev(temp); + strcpy(temp,"/sys/class"); + find_dev(temp); + + /* Hotplug */ + + } else { + action = getenv("ACTION"); + env_path = getenv("DEVPATH"); + if (!action || !env_path) + bb_show_usage(); + + sprintf(temp, "/sys%s", env_path); + if (!strcmp(action, "add")) make_device(temp,0); + else if (!strcmp(action, "remove")) make_device(temp,1); + } + + if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp); + return 0; +} |