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Diffstat (limited to 'toys/other/mdev.c')
| -rw-r--r-- | toys/other/mdev.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/toys/other/mdev.c b/toys/other/mdev.c new file mode 100644 index 00000000..b769828f --- /dev/null +++ b/toys/other/mdev.c @@ -0,0 +1,213 @@ +/* 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 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 + + 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" + +// todo, open() block devices to trigger partition scanning. + +// 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 = toybuf; + 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 = 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 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; + 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 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); + + if (CFG_MDEV_CONF) mode=chown(temp, 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"). + + return (node->parent && node->parent->parent) ? 0 : DIRTREE_RECURSE; +} + +void mdev_main(void) +{ + // Handle -s + + if (toys.optflags) { + dirtree_read("/sys/class", callback); + dirtree_read("/sys/block", callback); + } + + // hotplug support goes here +} |