| /* mdev.c - Populate /dev directory and handle hotplug events |
| * |
| * Copyright 2005, 2008 Rob Landley <rob@landley.net> |
| * Copyright 2005 Frank Sorenson <frank@tuxrocks.com> |
| |
| USE_MDEV(NEWTOY(mdev, "s", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_UMASK)) |
| |
| 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 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 |
| (sd[a-z]) root:disk 660 =usb_storage |
| |
| Each line must contain three whitespace separated fields. The first |
| field is a regular expression matching one or more device names, |
| the second and third fields are uid:gid and file permissions for |
| matching devices. Fourth field is optional. It could be used to change |
| device name (prefix '='), path (prefix '=' and postfix '/') or create a |
| symlink (prefix '>'). |
| */ |
| |
| #include "toys.h" |
| #include <stdbool.h> |
| |
| // mknod in /dev based on a path like "/sys/block/hda/hda1" |
| static void make_device(char *path) |
| { |
| char *device_name = 0, *custom_name = 0, *s, *temp; |
| bool create_symlink = false; |
| int major = 0, minor = 0, type, len, fd, mode = 0660; |
| uid_t uid = 0; |
| gid_t gid = 0; |
| |
| if (path) { |
| |
| // Try to read major/minor string, returning if we can't |
| temp = strrchr(path, '/'); |
| fd = open(path, O_RDONLY); |
| *temp = 0; |
| len = read(fd, toybuf, 64); |
| close(fd); |
| if (len<1) return; |
| toybuf[len] = 0; |
| |
| // Determine device type, major and minor |
| |
| type = path[5]=='c' ? S_IFCHR : S_IFBLK; |
| sscanf(toybuf, "%u:%u", &major, &minor); |
| } else { |
| // if (!path), do hotplug |
| |
| if (!(temp = getenv("MODALIAS"))) xrun((char *[]){"modprobe", temp, 0}); |
| if (!(temp = getenv("SUBSYSTEM"))) return; |
| type = strcmp(temp, "block") ? S_IFCHR : S_IFBLK; |
| if (!(temp = getenv("MAJOR"))) return; |
| sscanf(temp, "%u", &major); |
| if (!(temp = getenv("MINOR"))) return; |
| sscanf(temp, "%u", &minor); |
| if (!(path = getenv("DEVPATH"))) return; |
| device_name = getenv("DEVNAME"); |
| } |
| if (!device_name) |
| device_name = strrchr(path, '/') + 1; |
| |
| // as in linux/drivers/base/core.c, device_get_devnode() |
| while ((temp = strchr(device_name, '!'))) { |
| *temp = '/'; |
| } |
| |
| // If we have a config file, look up permissions for this device |
| |
| if (CFG_MDEV_CONF) { |
| char *conf, *pos, *end; |
| bool optional_field_valid = false; |
| |
| // mmap the config file |
| if (-1!=(fd = open("/etc/mdev.conf", O_RDONLY))) { |
| int line = 0; |
| |
| len = fdlength(fd); |
| conf = xmmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 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++); |
| |
| // Four fields (last is optional): regex, uid:gid, mode [, name|path ] |
| // For example: (sd[a-z])1 root:disk 660 =usb_storage_p1 |
| for (field = 4; 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 4: |
| { |
| char *regex = strndup(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); |
| free(regex); |
| |
| // 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 3: |
| { |
| 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; |
| char *str = strndup(pos, s-pos); |
| pass = getpwnam(str); |
| free(str); |
| if (!pass) goto end_line; |
| uid = pass->pw_uid; |
| } |
| s++; |
| // parse GID |
| gid = strtoul(s,&s2,10); |
| if (end2!=s2) { |
| struct group *grp; |
| char *str = strndup(s, end2-s); |
| grp = getgrnam(str); |
| free(str); |
| if (!grp) goto end_line; |
| gid = grp->gr_gid; |
| } |
| break; |
| } |
| // mode |
| case 2: |
| { |
| char *beg_pos = pos; |
| mode = strtoul(pos, &pos, 8); |
| if (pos == beg_pos) { |
| // The line is bad because mode setting could not be |
| // converted to numeric value. |
| goto end_line; |
| } |
| break; |
| } |
| // Try to look for name or path (optional field) |
| case 1: |
| { |
| if(pos < end2){ |
| //char *name = strndup(pos, end2-pos); |
| char *name = malloc(end2-pos+1); |
| if(name){ |
| strncpy(name, pos, end2-pos+1); |
| name[end2-pos] = '\0'; |
| switch(name[0]){ |
| case '>': |
| create_symlink = true; |
| case '=': |
| custom_name = strdup(&name[1]); |
| break; |
| case '!': |
| device_name = NULL; |
| break; |
| default: |
| free(name); |
| goto end_line; |
| } |
| free(name); |
| optional_field_valid = true; |
| } |
| } |
| goto found_device; |
| } |
| } |
| pos=end2; |
| } |
| end_line: |
| // Did everything parse happily? |
| // Note: Last field is optional. |
| if ((field>1 || (field==1 && !optional_field_valid)) && field!=4) |
| error_exit("Bad line %d", line); |
| // Next line |
| pos = ++end; |
| } |
| found_device: |
| munmap(conf, len); |
| } |
| close(fd); |
| } |
| |
| if(device_name) { |
| if(custom_name) { |
| sprintf(toybuf, "/dev/%s", custom_name); |
| if(custom_name[strlen(custom_name) - 1] == '/') { |
| DIR *dir; |
| dir = opendir(toybuf); |
| if(dir) closedir(dir); |
| else mkdir(toybuf, 0755); |
| } |
| } |
| else |
| sprintf(toybuf, "/dev/%s", device_name); |
| |
| if ((temp=getenv("ACTION")) && !strcmp(temp, "remove")) { |
| unlink(toybuf); |
| return; |
| } |
| |
| if (strchr(device_name, '/')) mkpath(toybuf); |
| if (mknod(toybuf, mode | type, dev_makedev(major, minor)) && |
| errno != EEXIST) |
| perror_exit("mknod %s failed", toybuf); |
| if(create_symlink){ |
| char *symlink_name = malloc(sizeof("/dev/") + strlen(device_name) + 1); |
| if(symlink_name == NULL) |
| perror_exit("malloc failed while creating symlink to %s", toybuf); |
| sprintf(symlink_name, "/dev/%s", device_name); |
| if(symlink(toybuf, symlink_name)){ |
| free(symlink_name); |
| perror_exit("symlink creation failed for %s", toybuf); |
| } |
| free(symlink_name); |
| } |
| |
| if (type == S_IFBLK) close(open(toybuf, O_RDONLY)); // scan for partitions |
| |
| if (CFG_MDEV_CONF) mode=chown(toybuf, uid, gid); |
| } |
| } |
| |
| static int callback(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 0; |
| |
| // Does this directory have a "dev" entry in it? |
| // This is path based because the hotplug callbacks are |
| if (S_ISDIR(node->st.st_mode) || S_ISLNK(node->st.st_mode)) { |
| int len=4; |
| char *dev = dirtree_path(node, &len); |
| strcpy(dev+len, "/dev"); |
| if (!access(dev, R_OK)) make_device(dev); |
| free(dev); |
| } |
| |
| // Circa 2.6.25 the entries more than 2 deep are all either redundant |
| // (mouse#, event#) or unnamed (every usb_* entry is called "device"). |
| |
| if (node->parent && node->parent->parent) return 0; |
| return DIRTREE_RECURSE|DIRTREE_SYMFOLLOW; |
| } |
| |
| void mdev_main(void) |
| { |
| // Handle -s |
| |
| if (toys.optflags) { |
| dirtree_read("/sys/class", callback); |
| if (!access("/sys/block", R_OK)) dirtree_read("/sys/block", callback); |
| } else { // hotplug support |
| make_device(NULL); |
| } |
| } |
