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#include <ctype.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <alloca.h>
#include <inttypes.h>
#include "do_mounts.h"
#include "kinit.h"
#define BUF_SZ 65536
/* Find dev_t for e.g. "hda,NULL" or "hdb,2" */
static dev_t try_name(char *name, int part)
{
char path[BUF_SZ];
char buf[BUF_SZ];
int range;
unsigned int major_num, minor_num;
dev_t res;
char *s;
int len;
int fd;
/* read device number from /sys/block/.../dev */
snprintf(path, sizeof(path), "/sys/block/%s/dev", name);
fd = open(path, 0, 0);
if (fd < 0)
goto fail;
len = read(fd, buf, BUF_SZ);
close(fd);
if (len <= 0 || len == BUF_SZ || buf[len - 1] != '\n')
goto fail;
buf[len - 1] = '\0';
major_num = strtoul(buf, &s, 10);
if (*s != ':')
goto fail;
minor_num = strtoul(s + 1, &s, 10);
if (*s)
goto fail;
res = makedev(major_num, minor_num);
/* if it's there and we are not looking for a partition - that's it */
if (!part)
return res;
/* otherwise read range from .../range */
snprintf(path, sizeof(path), "/sys/block/%s/range", name);
fd = open(path, 0, 0);
if (fd < 0)
goto fail;
len = read(fd, buf, 32);
close(fd);
if (len <= 0 || len == 32 || buf[len - 1] != '\n')
goto fail;
buf[len - 1] = '\0';
range = strtoul(buf, &s, 10);
if (*s)
goto fail;
/* if partition is within range - we got it */
if (part < range) {
dprintf("kinit: try_name %s,%d = %s\n", name, part,
bdevname(res + part));
return res + part;
}
fail:
return (dev_t) 0;
}
/*
* Convert a name into device number. We accept the following variants:
*
* 1) device number in hexadecimal represents itself
* 2) device number in major:minor decimal represents itself
* 3) /dev/nfs represents Root_NFS
* 4) /dev/<disk_name> represents the device number of disk
* 5) /dev/<disk_name><decimal> represents the device number
* of partition - device number of disk plus the partition number
* 6) /dev/<disk_name>p<decimal> - same as the above, that form is
* used when disk name of partitioned disk ends on a digit.
* 7) an actual block device node in the initramfs filesystem
*
* If name doesn't have fall into the categories above, we return 0.
* Driverfs is used to check if something is a disk name - it has
* all known disks under bus/block/devices. If the disk name
* contains slashes, name of driverfs node has them replaced with
* dots. try_name() does the actual checks, assuming that driverfs
* is mounted on rootfs /sys.
*/
static inline dev_t name_to_dev_t_real(const char *name)
{
char *p;
dev_t res = 0;
char *s;
int part;
struct stat st;
int len;
const char *devname;
char *cptr, *e1, *e2;
int major_num, minor_num;
/* Are we a multi root line? */
if (strchr(name, ','))
return Root_MULTI;
if (name[0] == '/') {
devname = name;
} else {
char *dname = alloca(strlen(name) + 6);
sprintf(dname, "/dev/%s", name);
devname = dname;
}
if (!stat(devname, &st) && S_ISBLK(st.st_mode))
return st.st_rdev;
if (strncmp(name, "/dev/", 5)) {
cptr = strchr(devname+5, ':');
if (cptr && cptr[1] != '\0') {
/* Colon-separated decimal device number */
*cptr = '\0';
major_num = strtoul(devname+5, &e1, 10);
minor_num = strtoul(cptr+1, &e2, 10);
if (!*e1 && !*e2)
return makedev(major_num, minor_num);
*cptr = ':';
} else {
/* Hexadecimal device number */
res = (dev_t) strtoul(name, &p, 16);
if (!*p)
return res;
}
} else {
name += 5;
}
if (!strcmp(name, "nfs"))
return Root_NFS;
if (!strcmp(name, "ram")) /* /dev/ram - historic alias for /dev/ram0 */
return Root_RAM0;
if (!strncmp(name, "mtd", 3))
return Root_MTD;
len = strlen(name);
s = alloca(len + 1);
memcpy(s, name, len + 1);
for (p = s; *p; p++)
if (*p == '/')
*p = '!';
res = try_name(s, 0);
if (res)
return res;
while (p > s && isdigit(p[-1]))
p--;
if (p == s || !*p || *p == '0')
goto fail;
part = strtoul(p, NULL, 10);
*p = '\0';
res = try_name(s, part);
if (res)
return res;
if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
goto fail;
p[-1] = '\0';
res = try_name(s, part);
return res;
fail:
return (dev_t) 0;
}
dev_t name_to_dev_t(const char *name)
{
dev_t dev = name_to_dev_t_real(name);
dprintf("kinit: name_to_dev_t(%s) = %s\n", name, bdevname(dev));
return dev;
}
#ifdef TEST_NAMETODEV /* Standalone test */
int main(int argc, char *argv[])
{
int i;
for (i = 1; i < argc; i++)
name_to_dev_t(argv[i]);
return 0;
}
#endif
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