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