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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 <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include "busybox.h"
#include "xregex.h"
#define DEV_PATH "/dev"
#include <busybox.h>
/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
static void make_device(char *path)
{
char *device_name,*s;
int major,minor,type,len,fd;
int mode=0660;
uid_t uid=0;
gid_t gid=0;
RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
/* Try to read major/minor string */
snprintf(temp, PATH_MAX, "%s/dev", path);
fd = open(temp, O_RDONLY);
len = read(fd, temp, PATH_MAX-1);
if (len<1) goto end;
temp[--len] = 0; // remove trailing \n
close(fd);
/* Determine device name, type, major and minor */
device_name = strrchr(path, '/') + 1;
type = strncmp(path+5, "block/" ,6) ? S_IFCHR : S_IFBLK;
major = minor = 0;
for (s = temp; *s; s++) {
if (*s == ':') {
major = minor;
minor = 0;
} else {
minor *= 10;
minor += (*s) - '0';
}
}
/* 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=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=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))
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;
pass=getpwnam(strndupa(pos,s-pos));
if(!pass) goto end_line;
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) 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)
bb_error_msg_and_die("Bad line %d",line);
/* Next line */
pos=++end;
}
found_device:
munmap(conf,len);
}
close(fd);
}
}
sprintf(temp, "%s/%s", DEV_PATH, device_name);
umask(0);
if (mknod(temp, mode | type, makedev(major, minor)) && errno != EEXIST)
bb_perror_msg_and_die("mknod %s failed", temp);
if (ENABLE_FEATURE_MDEV_CONF) chown(temp,uid,gid);
end:
RELEASE_CONFIG_BUFFER(temp);
}
/* 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;
int len=strlen(path);
if (!(dir = opendir(path)))
bb_perror_msg_and_die("No %s",path);
for (;;) {
struct dirent *entry = readdir(dir);
if (!entry) break;
/* Skip "." and ".." (also skips hidden files, which is ok) */
if (entry->d_name[0]=='.') continue;
if (entry->d_type == DT_DIR) {
snprintf(path+len, PATH_MAX-len, "/%s", entry->d_name);
find_dev(path);
path[len] = 0;
}
/* If there's a dev entry, mknod it */
if (strcmp(entry->d_name, "dev")) make_device(path);
}
closedir(dir);
}
int mdev_main(int argc, char *argv[])
{
char *action;
char *env_path;
RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
/* Scan */
if (argc == 2 && !strcmp(argv[1],"-s")) {
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();
if (!strcmp(action, "add")) {
sprintf(temp, "/sys%s", env_path);
make_device(temp);
} else if (!strcmp(action, "remove")) {
sprintf(temp, "%s/%s", DEV_PATH, strrchr(env_path, '/') + 1);
unlink(temp);
}
}
if(ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp);
return 0;
}
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