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#include <linux/kernel.h>
#include <linux/dirent.h>
#include <linux/string.h>
#include "do_mounts.h"
extern asmlinkage long sys_symlink(const char *old, const char *new);
extern asmlinkage long sys_access(const char * filename, int mode);
extern asmlinkage long sys_getdents64(unsigned int fd, void * dirent,
unsigned int count);
void __init mount_devfs(void)
{
sys_mount("devfs", "/dev", "devfs", 0, NULL);
}
void __init umount_devfs(char *path)
{
sys_umount(path, 0);
}
/*
* If the dir will fit in *buf, return its length. If it won't fit, return
* zero. Return -ve on error.
*/
static int __init do_read_dir(int fd, void *buf, int len)
{
long bytes, n;
char *p = buf;
lseek(fd, 0, 0);
for (bytes = 0; bytes < len; bytes += n) {
n = sys_getdents64(fd, p + bytes, len - bytes);
if (n < 0)
return n;
if (n == 0)
return bytes;
}
return 0;
}
/*
* Try to read all of a directory. Returns the contents at *p, which
* is kmalloced memory. Returns the number of bytes read at *len. Returns
* NULL on error.
*/
static void * __init read_dir(char *path, int *len)
{
int size;
int fd = open(path, 0, 0);
*len = 0;
if (fd < 0)
return NULL;
for (size = 1 << 9; size <= (1 << MAX_ORDER); size <<= 1) {
void *p = kmalloc(size, GFP_KERNEL);
int n;
if (!p)
break;
n = do_read_dir(fd, p, size);
if (n > 0) {
close(fd);
*len = n;
return p;
}
kfree(p);
if (n == -EINVAL)
continue; /* Try a larger buffer */
if (n < 0)
break;
}
close(fd);
return NULL;
}
/*
* recursively scan <path>, looking for a device node of type <dev>
*/
static int __init find_in_devfs(char *path, dev_t dev)
{
struct stat buf;
char *end = path + strlen(path);
int rest = path + 64 - end;
int size;
char *p = read_dir(path, &size);
char *s;
if (!p)
return -1;
for (s = p; s < p + size; s += ((struct linux_dirent64 *)s)->d_reclen) {
struct linux_dirent64 *d = (struct linux_dirent64 *)s;
if (strlen(d->d_name) + 2 > rest)
continue;
switch (d->d_type) {
case DT_BLK:
sprintf(end, "/%s", d->d_name);
if (sys_newstat(path, &buf) < 0)
break;
if (!S_ISBLK(buf.st_mode))
break;
if (buf.st_rdev != dev)
break;
kfree(p);
return 0;
case DT_DIR:
if (strcmp(d->d_name, ".") == 0)
break;
if (strcmp(d->d_name, "..") == 0)
break;
sprintf(end, "/%s", d->d_name);
if (find_in_devfs(path, dev) < 0)
break;
kfree(p);
return 0;
}
}
kfree(p);
return -1;
}
/*
* create a device node called <name> which points to
* <devfs_name> if possible, otherwise find a device node
* which matches <dev> and make <name> a symlink pointing to it.
*/
int __init create_dev(char *name, dev_t dev, char *devfs_name)
{
char path[64];
sys_unlink(name);
if (devfs_name && devfs_name[0]) {
if (strncmp(devfs_name, "/dev/", 5) == 0)
devfs_name += 5;
sprintf(path, "/dev/%s", devfs_name);
if (sys_access(path, 0) == 0)
return sys_symlink(devfs_name, name);
}
if (!dev)
return -1;
strcpy(path, "/dev");
if (find_in_devfs(path, dev) < 0)
return -1;
return sys_symlink(path + 5, name);
}
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