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/* vi:set ts=4:
*
* mdev - Mini udev for busybox
*
* Copyright 2005 Rob Landley <rob@landley.net>
* Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "busybox.h"
#include <ctype.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/sysmacros.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, fd;
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. */
strcat(path, "/dev");
fd = open(path, O_RDONLY);
len = read(fd, temp + 1, 64);
*temp++ = 0;
close(fd);
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 (sscanf(temp, "%d:%d", &major, &minor) != 2) return;
/* If we have a config file, look up permissions for this device */
if (ENABLE_FEATURE_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=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) {
/* 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;
} else 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;
}
} else if (field == 2) {
/* mode */
mode = strtoul(pos, &pos, 8);
if (pos != end2) break;
} else if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
// Command to run
char *s = "@$*", *s2;
if (!(s2 = strchr(s, *pos++))) {
// Force error
field = 1;
break;
}
if ((s2-s+1) & (1<<delete))
command = bb_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);
}
close(fd);
}
}
umask(0);
if (!delete) {
if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
bb_perror_msg_and_die("mknod %s failed", 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=bb_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("Couldn't 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;
if ((dir = opendir(path)) == 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);
bb_xchdir(DEV_PATH);
/* Scan */
if (argc == 2 && !strcmp(argv[1],"-s")) {
struct stat st;
stat("/", &st); // If this fails, we have bigger problems.
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;
}
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