kernel26-2.6.12-alx-r9/init/do_mounts_devfs.c


#include <linux/kernel.h>
#include <linux/dirent.h>
#include <linux/string.h>

#include "do_mounts.h"

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;
	sys_lseek(fd, 0, 0);

	for (bytes = 0; bytes < len; bytes += n) {
		n = sys_getdents64(fd, (struct linux_dirent64 *)(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 = sys_open(path, 0, 0);

	*len = 0;
	if (fd < 0)
		return NULL;

	for (size = 1 << 9; size <= (PAGE_SIZE << 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) {
			sys_close(fd);
			*len = n;
			return p;
		}
		kfree(p);
		if (n == -EINVAL)
			continue;	/* Try a larger buffer */
		if (n < 0)
			break;
	}
	sys_close(fd);
	return NULL;
}

/*
 * recursively scan <path>, looking for a device node of type <dev>
 */
static int __init find_in_devfs(char *path, unsigned dev)
{
	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 (bstat(path) != 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, new_encode_dev(dev)) < 0)
		return -1;
	return sys_symlink(path + 5, name);
}
1
2	#include <linux/kernel.h>
3	#include <linux/dirent.h>
4	#include <linux/string.h>
5
6	#include "do_mounts.h"
7
8	void __init mount_devfs(void)
9	{
10	sys_mount("devfs", "/dev", "devfs", 0, NULL);
11	}
12
13	void __init umount_devfs(char *path)
14	{
15	sys_umount(path, 0);
16	}
17
18	/*
19	* If the dir will fit in *buf, return its length. If it won't fit, return
20	* zero. Return -ve on error.
21	*/
22	static int __init do_read_dir(int fd, void *buf, int len)
23	{
24	long bytes, n;
25	char *p = buf;
26	sys_lseek(fd, 0, 0);
27
28	for (bytes = 0; bytes < len; bytes += n) {
29	n = sys_getdents64(fd, (struct linux_dirent64 *)(p + bytes),
30	len - bytes);
31	if (n < 0)
32	return n;
33	if (n == 0)
34	return bytes;
35	}
36	return 0;
37	}
38
39	/*
40	* Try to read all of a directory. Returns the contents at *p, which
41	* is kmalloced memory. Returns the number of bytes read at *len. Returns
42	* NULL on error.
43	*/
44	static void * __init read_dir(char path, int len)
45	{
46	int size;
47	int fd = sys_open(path, 0, 0);
48
49	*len = 0;
50	if (fd < 0)
51	return NULL;
52
53	for (size = 1 << 9; size <= (PAGE_SIZE << MAX_ORDER); size <<= 1) {
54	void *p = kmalloc(size, GFP_KERNEL);
55	int n;
56	if (!p)
57	break;
58	n = do_read_dir(fd, p, size);
59	if (n > 0) {
60	sys_close(fd);
61	*len = n;
62	return p;
63	}
64	kfree(p);
65	if (n == -EINVAL)
66	continue; /* Try a larger buffer */
67	if (n < 0)
68	break;
69	}
70	sys_close(fd);
71	return NULL;
72	}
73
74	/*
75	* recursively scan <path>, looking for a device node of type <dev>
76	*/
77	static int __init find_in_devfs(char *path, unsigned dev)
78	{
79	char *end = path + strlen(path);
80	int rest = path + 64 - end;
81	int size;
82	char *p = read_dir(path, &size);
83	char *s;
84
85	if (!p)
86	return -1;
87	for (s = p; s < p + size; s += ((struct linux_dirent64 *)s)->d_reclen) {
88	struct linux_dirent64 d = (struct linux_dirent64 )s;
89	if (strlen(d->d_name) + 2 > rest)
90	continue;
91	switch (d->d_type) {
92	case DT_BLK:
93	sprintf(end, "/%s", d->d_name);
94	if (bstat(path) != dev)
95	break;
96	kfree(p);
97	return 0;
98	case DT_DIR:
99	if (strcmp(d->d_name, ".") == 0)
100	break;
101	if (strcmp(d->d_name, "..") == 0)
102	break;
103	sprintf(end, "/%s", d->d_name);
104	if (find_in_devfs(path, dev) < 0)
105	break;
106	kfree(p);
107	return 0;
108	}
109	}
110	kfree(p);
111	return -1;
112	}
113
114	/*
115	* create a device node called <name> which points to
116	* <devfs_name> if possible, otherwise find a device node
117	* which matches <dev> and make <name> a symlink pointing to it.
118	*/
119	int __init create_dev(char name, dev_t dev, char devfs_name)
120	{
121	char path[64];
122
123	sys_unlink(name);
124	if (devfs_name && devfs_name[0]) {
125	if (strncmp(devfs_name, "/dev/", 5) == 0)
126	devfs_name += 5;
127	sprintf(path, "/dev/%s", devfs_name);
128	if (sys_access(path, 0) == 0)
129	return sys_symlink(devfs_name, name);
130	}
131	if (!dev)
132	return -1;
133	strcpy(path, "/dev");
134	if (find_in_devfs(path, new_encode_dev(dev)) < 0)
135	return -1;
136	return sys_symlink(path + 5, name);
137	}