usr/kinit/do_mounts.c

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mount.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"
#include "fstype.h"
#include "zlib.h"

/* Create the device node "name" */
int create_dev(const char *name, dev_t dev)
{
	unlink(name);
	return mknod(name, S_IFBLK | 0600, dev);
}

/* mount a filesystem, possibly trying a set of different types */
const char *mount_block(const char *source, const char *target,
			const char *type, unsigned long flags,
			const void *data)
{
	char *fslist, *p, *ep;
	const char *rp;
	ssize_t fsbytes;
	int fd;

	if (type) {
		dprintf("kinit: trying to mount %s on %s with type %s\n",
			source, target, type);
		int rv = mount(source, target, type, flags, data);
		/* Mount readonly if necessary */
		if (rv == -1 && errno == EACCES && !(flags & MS_RDONLY))
			rv = mount(source, target, type, flags | MS_RDONLY,
				   data);
		return rv ? NULL : type;
	}

	/* If no type given, try to identify the type first; this
	   also takes care of specific ordering requirements, like
	   ext3 before ext2... */
	fd = open(source, O_RDONLY);
	if (fd >= 0) {
		int err = identify_fs(fd, &type, NULL, 0);
		close(fd);

		if (!err && type) {
			dprintf("kinit: %s appears to be a %s filesystem\n",
				source, type);
			type = mount_block(source, target, type, flags, data);
			if (type)
				return type;
		}
	}

	dprintf("kinit: failed to identify filesystem %s, trying all\n",
		source);

	fsbytes = readfile("/proc/filesystems", &fslist);

	errno = EINVAL;
	if (fsbytes < 0)
		return NULL;

	p = fslist;
	ep = fslist + fsbytes;

	rp = NULL;

	while (p < ep) {
		type = p;
		p = strchr(p, '\n');
		if (!p)
			break;
		*p++ = '\0';
		if (*type != '\t')	/* We can't mount a block device as a "nodev" fs */
			continue;

		type++;
		rp = mount_block(source, target, type, flags, data);
		if (rp)
			break;
		if (errno != EINVAL)
			break;
	}

	free(fslist);
	return rp;
}

/* mount the root filesystem from a block device */
static int
mount_block_root(int argc, char *argv[], dev_t root_dev,
		 const char *type, unsigned long flags)
{
	const char *data, *rp;

	data = get_arg(argc, argv, "rootflags=");
	create_dev("/dev/root", root_dev);

	errno = 0;

	if (type) {
		if ((rp = mount_block("/dev/root", "/root", type, flags, data)))
			goto ok;
		if (errno != EINVAL)
			goto bad;
	}

	if (!errno
	    && (rp = mount_block("/dev/root", "/root", NULL, flags, data)))
		goto ok;

      bad:
	if (errno != EINVAL) {
		/*
		 * Allow the user to distinguish between failed open
		 * and bad superblock on root device.
		 */
		fprintf(stderr, "%s: Cannot open root device %s\n",
			progname, bdevname(root_dev));
		return -errno;
	} else {
		fprintf(stderr, "%s: Unable to mount root fs on device %s\n",
			progname, bdevname(root_dev));
		return -ESRCH;
	}

      ok:
	printf("%s: Mounted root (%s filesystem)%s.\n",
	       progname, rp, (flags & MS_RDONLY) ? " readonly" : "");
	return 0;
}

static int
mount_roots(int argc, char *argv[], const char *root_dev_name)
{
	char *roots = strdup(root_dev_name);
	char *root;
	const char *sep = ",";
	char *saveptr;
	int ret = -ESRCH;

	root = strtok_r(roots, sep, &saveptr);
	while (root) {
		dev_t root_dev;

		dprintf("kinit: trying to mount %s\n", root);
		root_dev = name_to_dev_t(root);
		ret = mount_root(argc, argv, root_dev, root);
		if (!ret)
			break;
		root = strtok_r(NULL, sep, &saveptr);
	}
	free(roots);
	return ret;
}

int
mount_root(int argc, char *argv[], dev_t root_dev, const char *root_dev_name)
{
	unsigned long flags = MS_RDONLY | MS_VERBOSE;
	int ret;
	const char *type = get_arg(argc, argv, "rootfstype=");

	if (get_flag(argc, argv, "rw") > get_flag(argc, argv, "ro")) {
		dprintf("kinit: mounting root rw\n");
		flags &= ~MS_RDONLY;
	}

	if (type) {
		if (!strcmp(type, "nfs"))
			root_dev = Root_NFS;
		else if (!strcmp(type, "jffs2") && !major(root_dev))
			root_dev = Root_MTD;
	}

	switch (root_dev) {
	case Root_NFS:
		ret = mount_nfs_root(argc, argv, flags);
		break;
	case Root_MTD:
		ret = mount_mtd_root(argc, argv, root_dev_name, type, flags);
		break;
	default:
		ret = mount_block_root(argc, argv, root_dev, type, flags);
		break;
	}

	if (!ret)
		chdir("/root");

	return ret;
}

int do_mounts(int argc, char *argv[])
{
	const char *root_dev_name = get_arg(argc, argv, "root=");
	const char *root_delay = get_arg(argc, argv, "rootdelay=");
	const char *load_ramdisk = get_arg(argc, argv, "load_ramdisk=");
	dev_t root_dev = 0;

	dprintf("kinit: do_mounts\n");

	if (root_delay) {
		int delay = atoi(root_delay);
		fprintf(stderr, "Waiting %d s before mounting root device...\n",
			delay);
		sleep(delay);
	}

	md_run(argc, argv);

	if (root_dev_name) {
		root_dev = name_to_dev_t(root_dev_name);
	} else if (get_arg(argc, argv, "nfsroot=") ||
		   get_arg(argc, argv, "nfsaddrs=")) {
		root_dev = Root_NFS;
	} else {
		long rootdev;
		getintfile("/proc/sys/kernel/real-root-dev", &rootdev);
		root_dev = (dev_t) rootdev;
	}

	dprintf("kinit: root_dev = %s\n", bdevname(root_dev));

	if (initrd_load(argc, argv, root_dev)) {
		dprintf("initrd loaded\n");
		return 0;
	}

	if (load_ramdisk && atoi(load_ramdisk)) {
		if (ramdisk_load(argc, argv))
			root_dev = Root_RAM0;
	}

	if (root_dev == Root_MULTI)
		return mount_roots(argc, argv, root_dev_name);
	return mount_root(argc, argv, root_dev, root_dev_name);
}
1	#include <ctype.h>
2	#include <errno.h>
3	#include <fcntl.h>
4	#include <sys/mount.h>
5	#include <sys/stat.h>
6	#include <stdio.h>
7	#include <stdlib.h>
8	#include <string.h>
9	#include <unistd.h>
10	#include <alloca.h>
11	#include <inttypes.h>
12
13	#include "do_mounts.h"
14	#include "kinit.h"
15	#include "fstype.h"
16	#include "zlib.h"
17
18	/* Create the device node "name" */
19	int create_dev(const char *name, dev_t dev)
20	{
21	unlink(name);
22	return mknod(name, S_IFBLK \| 0600, dev);
23	}
24
25	/* mount a filesystem, possibly trying a set of different types */
26	const char mount_block(const char source, const char *target,
27	const char *type, unsigned long flags,
28	const void *data)
29	{
30	char fslist, p, *ep;
31	const char *rp;
32	ssize_t fsbytes;
33	int fd;
34
35	if (type) {
36	dprintf("kinit: trying to mount %s on %s with type %s\n",
37	source, target, type);
38	int rv = mount(source, target, type, flags, data);
39	/* Mount readonly if necessary */
40	if (rv == -1 && errno == EACCES && !(flags & MS_RDONLY))
41	rv = mount(source, target, type, flags \| MS_RDONLY,
42	data);
43	return rv ? NULL : type;
44	}
45
46	/* If no type given, try to identify the type first; this
47	also takes care of specific ordering requirements, like
48	ext3 before ext2... */
49	fd = open(source, O_RDONLY);
50	if (fd >= 0) {
51	int err = identify_fs(fd, &type, NULL, 0);
52	close(fd);
53
54	if (!err && type) {
55	dprintf("kinit: %s appears to be a %s filesystem\n",
56	source, type);
57	type = mount_block(source, target, type, flags, data);
58	if (type)
59	return type;
60	}
61	}
62
63	dprintf("kinit: failed to identify filesystem %s, trying all\n",
64	source);
65
66	fsbytes = readfile("/proc/filesystems", &fslist);
67
68	errno = EINVAL;
69	if (fsbytes < 0)
70	return NULL;
71
72	p = fslist;
73	ep = fslist + fsbytes;
74
75	rp = NULL;
76
77	while (p < ep) {
78	type = p;
79	p = strchr(p, '\n');
80	if (!p)
81	break;
82	*p++ = '\0';
83	if (type != '\t') / We can't mount a block device as a "nodev" fs */
84	continue;
85
86	type++;
87	rp = mount_block(source, target, type, flags, data);
88	if (rp)
89	break;
90	if (errno != EINVAL)
91	break;
92	}
93
94	free(fslist);
95	return rp;
96	}
97
98	/* mount the root filesystem from a block device */
99	static int
100	mount_block_root(int argc, char *argv[], dev_t root_dev,
101	const char *type, unsigned long flags)
102	{
103	const char data, rp;
104
105	data = get_arg(argc, argv, "rootflags=");
106	create_dev("/dev/root", root_dev);
107
108	errno = 0;
109
110	if (type) {
111	if ((rp = mount_block("/dev/root", "/root", type, flags, data)))
112	goto ok;
113	if (errno != EINVAL)
114	goto bad;
115	}
116
117	if (!errno
118	&& (rp = mount_block("/dev/root", "/root", NULL, flags, data)))
119	goto ok;
120
121	bad:
122	if (errno != EINVAL) {
123	/*
124	* Allow the user to distinguish between failed open
125	* and bad superblock on root device.
126	*/
127	fprintf(stderr, "%s: Cannot open root device %s\n",
128	progname, bdevname(root_dev));
129	return -errno;
130	} else {
131	fprintf(stderr, "%s: Unable to mount root fs on device %s\n",
132	progname, bdevname(root_dev));
133	return -ESRCH;
134	}
135
136	ok:
137	printf("%s: Mounted root (%s filesystem)%s.\n",
138	progname, rp, (flags & MS_RDONLY) ? " readonly" : "");
139	return 0;
140	}
141
142	static int
143	mount_roots(int argc, char argv[], const char root_dev_name)
144	{
145	char *roots = strdup(root_dev_name);
146	char *root;
147	const char *sep = ",";
148	char *saveptr;
149	int ret = -ESRCH;
150
151	root = strtok_r(roots, sep, &saveptr);
152	while (root) {
153	dev_t root_dev;
154
155	dprintf("kinit: trying to mount %s\n", root);
156	root_dev = name_to_dev_t(root);
157	ret = mount_root(argc, argv, root_dev, root);
158	if (!ret)
159	break;
160	root = strtok_r(NULL, sep, &saveptr);
161	}
162	free(roots);
163	return ret;
164	}
165
166	int
167	mount_root(int argc, char argv[], dev_t root_dev, const char root_dev_name)
168	{
169	unsigned long flags = MS_RDONLY \| MS_VERBOSE;
170	int ret;
171	const char *type = get_arg(argc, argv, "rootfstype=");
172
173	if (get_flag(argc, argv, "rw") > get_flag(argc, argv, "ro")) {
174	dprintf("kinit: mounting root rw\n");
175	flags &= ~MS_RDONLY;
176	}
177
178	if (type) {
179	if (!strcmp(type, "nfs"))
180	root_dev = Root_NFS;
181	else if (!strcmp(type, "jffs2") && !major(root_dev))
182	root_dev = Root_MTD;
183	}
184
185	switch (root_dev) {
186	case Root_NFS:
187	ret = mount_nfs_root(argc, argv, flags);
188	break;
189	case Root_MTD:
190	ret = mount_mtd_root(argc, argv, root_dev_name, type, flags);
191	break;
192	default:
193	ret = mount_block_root(argc, argv, root_dev, type, flags);
194	break;
195	}
196
197	if (!ret)
198	chdir("/root");
199
200	return ret;
201	}
202
203	int do_mounts(int argc, char *argv[])
204	{
205	const char *root_dev_name = get_arg(argc, argv, "root=");
206	const char *root_delay = get_arg(argc, argv, "rootdelay=");
207	const char *load_ramdisk = get_arg(argc, argv, "load_ramdisk=");
208	dev_t root_dev = 0;
209
210	dprintf("kinit: do_mounts\n");
211
212	if (root_delay) {
213	int delay = atoi(root_delay);
214	fprintf(stderr, "Waiting %d s before mounting root device...\n",
215	delay);
216	sleep(delay);
217	}
218
219	md_run(argc, argv);
220
221	if (root_dev_name) {
222	root_dev = name_to_dev_t(root_dev_name);
223	} else if (get_arg(argc, argv, "nfsroot=") \|\|
224	get_arg(argc, argv, "nfsaddrs=")) {
225	root_dev = Root_NFS;
226	} else {
227	long rootdev;
228	getintfile("/proc/sys/kernel/real-root-dev", &rootdev);
229	root_dev = (dev_t) rootdev;
230	}
231
232	dprintf("kinit: root_dev = %s\n", bdevname(root_dev));
233
234	if (initrd_load(argc, argv, root_dev)) {
235	dprintf("initrd loaded\n");
236	return 0;
237	}
238
239	if (load_ramdisk && atoi(load_ramdisk)) {
240	if (ramdisk_load(argc, argv))
241	root_dev = Root_RAM0;
242	}
243
244	if (root_dev == Root_MULTI)
245	return mount_roots(argc, argv, root_dev_name);
246	return mount_root(argc, argv, root_dev, root_dev_name);
247	}