/* 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" struct globals { int root_major, root_minor; }; #define G (*(struct globals*)&bb_common_bufsiz1) #define root_major (G.root_major) #define root_minor (G.root_minor) #define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */ /* We use additional 64+ bytes in make_device() */ #define SCRATCH_SIZE 80 static char *next_field(char *s) { char *end = skip_non_whitespace(s); s = skip_whitespace(end); *end = '\0'; if (*s == '\0') s = NULL; return s; } /* mknod in /dev based on a path like "/sys/block/hda/hda1" */ /* NB: "mdev -s" may call us many times, do not leak memory/fds! */ static void make_device(char *path, int delete) { const char *device_name; int major, minor, type, len; int mode = 0660; uid_t uid = 0; gid_t gid = 0; char *dev_maj_min = path + strlen(path); char *command = NULL; char *alias = NULL; char aliaslink = aliaslink; /* for compiler */ /* Force the configuration file settings exactly. */ umask(0); /* 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) { 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, so just try to run script */ *dev_maj_min = '\0'; } } /* Determine device name, type, major and minor */ device_name = bb_basename(path); /* http://kernel.org/doc/pending/hotplug.txt says that only * "/sys/block/..." is for block devices. "/sys/bus" etc is not! * Since kernel 2.6.25 block devices are also in /sys/class/block. */ /* TODO: would it be acceptable to just use strstr(path, "/block/")? */ if (strncmp(&path[5], "class/block/"+6, 6) != 0 && strncmp(&path[5], "class/block/", 12) != 0) type = S_IFCHR; else type = S_IFBLK; if (ENABLE_FEATURE_MDEV_CONF) { FILE *fp; char *line, *val, *next; unsigned lineno = 0; /* If we have config file, look up user settings */ fp = fopen_or_warn("/etc/mdev.conf", "r"); if (!fp) goto end_parse; while ((line = xmalloc_fgetline(fp)) != NULL) { regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP]; ++lineno; trim(line); if (!line[0]) goto next_line; /* Fields: regex uid:gid mode [alias] [cmd] */ /* 1st field: regex to match this device */ next = next_field(line); { regex_t match; int result; /* Is this it? */ xregcomp(&match, line, REG_EXTENDED); result = regexec(&match, device_name, 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 not this device, skip rest of line */ /* (regexec returns whole pattern as "range" 0) */ if (result || off[0].rm_so || ((int)off[0].rm_eo != (int)strlen(device_name)) ) { goto next_line; } } /* This line matches: stop parsing the file * after parsing the rest of fields */ /* 2nd field: uid:gid - device ownership */ if (!next) /* field must exist */ bb_error_msg_and_die("bad line %u", lineno); val = next; next = next_field(val); { struct passwd *pass; struct group *grp; char *str_uid = val; char *str_gid = strchrnul(val, ':'); if (*str_gid) *str_gid++ = '\0'; /* Parse UID */ pass = getpwnam(str_uid); if (pass) uid = pass->pw_uid; else uid = strtoul(str_uid, NULL, 10); /* Parse GID */ grp = getgrnam(str_gid); if (grp) gid = grp->gr_gid; else gid = strtoul(str_gid, NULL, 10); } /* 3rd field: mode - device permissions */ if (!next) /* field must exist */ bb_error_msg_and_die("bad line %u", lineno); val = next; next = next_field(val); mode = strtoul(val, NULL, 8); /* 4th field (opt): >alias */ #if ENABLE_FEATURE_MDEV_RENAME if (!next) break; if (*next == '>' || *next == '=') { #if ENABLE_FEATURE_MDEV_RENAME_REGEXP char *s, *p; unsigned i, n; aliaslink = *next; val = next; next = next_field(val); /* substitute %1..9 with off[1..9], if any */ n = 0; s = val; while (*s) if (*s++ == '%') n++; p = alias = xzalloc(strlen(val) + n * strlen(device_name)); s = val + 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, device_name + off[i].rm_so, n); p += n - 1; s++; } } p++; s++; } #else aliaslink = *next; val = next; next = next_field(val); alias = xstrdup(val + 1); #endif } #endif /* ENABLE_FEATURE_MDEV_RENAME */ /* The rest (opt): command to run */ if (!next) break; val = next; if (ENABLE_FEATURE_MDEV_EXEC) { const char *s = "@$*"; const char *s2 = strchr(s, *val); if (!s2) bb_error_msg_and_die("bad line %u", lineno); /* Correlate the position in the "@$*" with the delete * step so that we get the proper behavior: * @cmd: run on create * $cmd: run on delete * *cmd: run on both */ if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) { command = xstrdup(val + 1); } } /* end of field parsing */ break; /* we found matching line, stop */ next_line: free(line); } /* end of "while line is read from /etc/mdev.conf" */ free(line); /* in case we used "break" to get here */ fclose(fp); } end_parse: if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) { if (ENABLE_FEATURE_MDEV_RENAME) unlink(device_name); if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST) bb_perror_msg_and_die("mknod %s", device_name); if (major == root_major && minor == root_minor) symlink(device_name, "root"); if (ENABLE_FEATURE_MDEV_CONF) { chown(device_name, uid, gid); if (ENABLE_FEATURE_MDEV_RENAME && alias) { 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); } } /* move the device, and optionally * make a symlink to moved device node */ if (rename(device_name, alias) == 0 && aliaslink == '>') symlink(alias, device_name); free(alias); } } } if (ENABLE_FEATURE_MDEV_EXEC && command) { /* setenv will leak memory, use putenv/unsetenv/free */ char *s = xasprintf("MDEV=%s", device_name); putenv(s); if (system(command) == -1) bb_perror_msg_and_die("can't run '%s'", command); s[4] = '\0'; unsetenv(s); free(s); free(command); } if (delete) unlink(device_name); } /* File callback for /sys/ traversal */ static int fileAction(const char *fileName, struct stat *statbuf ATTRIBUTE_UNUSED, void *userData, int depth ATTRIBUTE_UNUSED) { size_t len = strlen(fileName) - 4; /* can't underflow */ char *scratch = userData; /* len check is for paranoid reasons */ if (strcmp(fileName + len, "/dev") || len >= PATH_MAX) return FALSE; strcpy(scratch, fileName); scratch[len] = '\0'; make_device(scratch, 0); return TRUE; } /* Directory callback for /sys/ traversal */ static int dirAction(const char *fileName ATTRIBUTE_UNUSED, struct stat *statbuf ATTRIBUTE_UNUSED, void *userData ATTRIBUTE_UNUSED, int depth) { 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/$DEVPATH/loading * - kernel loads firmware into device */ static void load_firmware(const char *const firmware, const char *const sysfs_path) { int cnt; int firmware_fd, loading_fd, data_fd; /* check for /lib/firmware/$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 by `cat /lib/firmware/$FIRMWARE > /sys/$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, char **argv) { char *action; char *env_path; RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE); #ifdef YOU_WANT_TO_DEBUG_HOTPLUG_EVENTS /* Kernel cannot provide suitable stdio fds for us, do it ourself */ /* Replace LOGFILE by other file or device name if you need */ #define LOGFILE "/dev/console" xmove_fd(xopen("/dev/null", O_RDONLY), STDIN_FILENO); xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDOUT_FILENO); xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDERR_FILENO); #endif xchdir("/dev"); if (argc == 2 && !strcmp(argv[1], "-s")) { /* Scan: * mdev -s */ struct stat st; xstat("/", &st); root_major = major(st.st_dev); root_minor = minor(st.st_dev); recursive_action("/sys/block", ACTION_RECURSE | ACTION_FOLLOWLINKS, fileAction, dirAction, temp, 0); recursive_action("/sys/class", ACTION_RECURSE | ACTION_FOLLOWLINKS, fileAction, dirAction, temp, 0); } else { /* Hotplug: * env ACTION=... DEVPATH=... mdev * ACTION can be "add" or "remove" * DEVPATH is like "/block/sda" or "/class/input/mice" */ action = getenv("ACTION"); env_path = getenv("DEVPATH"); if (!action || !env_path) bb_show_usage(); snprintf(temp, PATH_MAX, "/sys%s", env_path); if (!strcmp(action, "remove")) make_device(temp, 1); else if (!strcmp(action, "add")) { make_device(temp, 0); if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) { char *fw = getenv("FIRMWARE"); if (fw) load_firmware(fw, temp); } } } if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp); return 0; }