int main(int argc, char** argv) {
int fd;
if(argc != 2) usage();
if ((fd = open(argv[1], O_RDWR)) == -1) die("open");
size_t pagesize = sysconf(_SC_PAGE_SIZE);
off_t len = fdlength(fd);
if (len < pagesize)
die("file to small");
size_t pages = (len/pagesize)-1;
unsigned int swap[129] = {0};
// Write header. Note that older kernel versions checked signature
// on disk (not in cache) during swapon, so sync after writing.
swap[0] = 1;
swap[1] = pages;
lseek(fd, 1024, SEEK_SET);
write(fd, swap, 129*sizeof(unsigned int));
lseek(fd, pagesize-10, SEEK_SET);
write(fd, "SWAPSPACE2", 10);
fsync(fd);
close(fd);
printf("Swapspace size: %luk\n", pages*(unsigned long)(pagesize/1024));
return 0;
}
int readahead_main(int argc, char **argv)
{
int retval = EXIT_SUCCESS;
if (argc == 1) bb_show_usage();
while (*++argv) {
int fd = open_or_warn(*argv, O_RDONLY);
if (fd >= 0) {
int r = readahead(fd, 0, fdlength(fd));
close(fd);
if (r >= 0) continue;
}
retval = EXIT_FAILURE;
}
return retval;
}
int readahead_main(int argc, char **argv)
{
FILE *f;
int retval = EXIT_SUCCESS;
if (argc == 1) bb_show_usage();
while (*++argv) {
if ((f = fopen_or_warn(*argv, "r")) != NULL) {
int r, fd=fileno(f);
r = readahead(fd, 0, fdlength(fd));
fclose(f);
if (r >= 0) continue;
}
retval = EXIT_FAILURE;
}
return retval;
}
// mknod in /dev based on a path like "/sys/block/hda/hda1"
static void make_device(char *path)
{
char *device_name = NULL, *s, *temp;
int major, minor, type, len, fd;
int mode = 0660;
uid_t uid = 0;
gid_t gid = 0;
if (path) {
// 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 type, major and minor
type = path[5]=='c' ? S_IFCHR : S_IFBLK;
major = minor = 0;
sscanf(temp, "%u:%u", &major, &minor);
} else {
// if (!path), do hotplug
if (!(temp = getenv("SUBSYSTEM")))
return;
type = strcmp(temp, "block") ? S_IFCHR : S_IFBLK;
major = minor = 0;
if (!(temp = getenv("MAJOR")))
return;
sscanf(temp, "%u", &major);
if (!(temp = getenv("MINOR")))
return;
sscanf(temp, "%u", &minor);
path = getenv("DEVPATH");
device_name = getenv("DEVNAME");
if (!path)
return;
temp = toybuf;
}
if (!device_name)
device_name = strrchr(path, '/') + 1;
// 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 (getenv("ACTION") && !strcmp(getenv("ACTION"), "remove")) {
unlink(temp);
return;
}
if (strchr(device_name, '/'))
mkpathat(AT_FDCWD, temp, 0, 2);
if (mknod(temp, mode | type, makedev(major, minor)) && errno != EEXIST)
perror_exit("mknod %s failed", temp);
if (type == S_IFBLK) close(open(temp, O_RDONLY)); // scan for partitions
if (CFG_MDEV_CONF) mode=chown(temp, uid, gid);
}