Root/init/do_mounts.c

1#include <linux/module.h>
2#include <linux/sched.h>
3#include <linux/ctype.h>
4#include <linux/fd.h>
5#include <linux/tty.h>
6#include <linux/suspend.h>
7#include <linux/root_dev.h>
8#include <linux/security.h>
9#include <linux/delay.h>
10#include <linux/genhd.h>
11#include <linux/mount.h>
12#include <linux/device.h>
13#include <linux/init.h>
14#include <linux/fs.h>
15#include <linux/initrd.h>
16#include <linux/async.h>
17#include <linux/fs_struct.h>
18#include <linux/slab.h>
19
20#include <linux/nfs_fs.h>
21#include <linux/nfs_fs_sb.h>
22#include <linux/nfs_mount.h>
23
24#include "do_mounts.h"
25
26int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
27
28int root_mountflags = MS_RDONLY | MS_SILENT;
29static char * __initdata root_device_name;
30static char __initdata saved_root_name[64];
31static int __initdata root_wait;
32
33dev_t ROOT_DEV;
34
35static int __init load_ramdisk(char *str)
36{
37    rd_doload = simple_strtol(str,NULL,0) & 3;
38    return 1;
39}
40__setup("load_ramdisk=", load_ramdisk);
41
42static int __init readonly(char *str)
43{
44    if (*str)
45        return 0;
46    root_mountflags |= MS_RDONLY;
47    return 1;
48}
49
50static int __init readwrite(char *str)
51{
52    if (*str)
53        return 0;
54    root_mountflags &= ~MS_RDONLY;
55    return 1;
56}
57
58__setup("ro", readonly);
59__setup("rw", readwrite);
60
61/*
62 * Convert a name into device number. We accept the following variants:
63 *
64 * 1) device number in hexadecimal represents itself
65 * 2) /dev/nfs represents Root_NFS (0xff)
66 * 3) /dev/<disk_name> represents the device number of disk
67 * 4) /dev/<disk_name><decimal> represents the device number
68 * of partition - device number of disk plus the partition number
69 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
70 * used when disk name of partitioned disk ends on a digit.
71 *
72 * If name doesn't have fall into the categories above, we return (0,0).
73 * block_class is used to check if something is a disk name. If the disk
74 * name contains slashes, the device name has them replaced with
75 * bangs.
76 */
77
78dev_t name_to_dev_t(char *name)
79{
80    char s[32];
81    char *p;
82    dev_t res = 0;
83    int part;
84
85    if (strncmp(name, "/dev/", 5) != 0) {
86        unsigned maj, min;
87
88        if (sscanf(name, "%u:%u", &maj, &min) == 2) {
89            res = MKDEV(maj, min);
90            if (maj != MAJOR(res) || min != MINOR(res))
91                goto fail;
92        } else {
93            res = new_decode_dev(simple_strtoul(name, &p, 16));
94            if (*p)
95                goto fail;
96        }
97        goto done;
98    }
99
100    name += 5;
101    res = Root_NFS;
102    if (strcmp(name, "nfs") == 0)
103        goto done;
104    res = Root_RAM0;
105    if (strcmp(name, "ram") == 0)
106        goto done;
107
108    if (strlen(name) > 31)
109        goto fail;
110    strcpy(s, name);
111    for (p = s; *p; p++)
112        if (*p == '/')
113            *p = '!';
114    res = blk_lookup_devt(s, 0);
115    if (res)
116        goto done;
117
118    /*
119     * try non-existant, but valid partition, which may only exist
120     * after revalidating the disk, like partitioned md devices
121     */
122    while (p > s && isdigit(p[-1]))
123        p--;
124    if (p == s || !*p || *p == '0')
125        goto fail;
126
127    /* try disk name without <part number> */
128    part = simple_strtoul(p, NULL, 10);
129    *p = '\0';
130    res = blk_lookup_devt(s, part);
131    if (res)
132        goto done;
133
134    /* try disk name without p<part number> */
135    if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
136        goto fail;
137    p[-1] = '\0';
138    res = blk_lookup_devt(s, part);
139    if (res)
140        goto done;
141
142fail:
143    return 0;
144done:
145    return res;
146}
147
148static int __init root_dev_setup(char *line)
149{
150    strlcpy(saved_root_name, line, sizeof(saved_root_name));
151    return 1;
152}
153
154__setup("root=", root_dev_setup);
155
156static int __init rootwait_setup(char *str)
157{
158    if (*str)
159        return 0;
160    root_wait = 1;
161    return 1;
162}
163
164__setup("rootwait", rootwait_setup);
165
166static char * __initdata root_mount_data;
167static int __init root_data_setup(char *str)
168{
169    root_mount_data = str;
170    return 1;
171}
172
173static char * __initdata root_fs_names;
174static int __init fs_names_setup(char *str)
175{
176    root_fs_names = str;
177    return 1;
178}
179
180static unsigned int __initdata root_delay;
181static int __init root_delay_setup(char *str)
182{
183    root_delay = simple_strtoul(str, NULL, 0);
184    return 1;
185}
186
187__setup("rootflags=", root_data_setup);
188__setup("rootfstype=", fs_names_setup);
189__setup("rootdelay=", root_delay_setup);
190
191static void __init get_fs_names(char *page)
192{
193    char *s = page;
194
195    if (root_fs_names) {
196        strcpy(page, root_fs_names);
197        while (*s++) {
198            if (s[-1] == ',')
199                s[-1] = '\0';
200        }
201    } else {
202        int len = get_filesystem_list(page);
203        char *p, *next;
204
205        page[len] = '\0';
206        for (p = page-1; p; p = next) {
207            next = strchr(++p, '\n');
208            if (*p++ != '\t')
209                continue;
210            while ((*s++ = *p++) != '\n')
211                ;
212            s[-1] = '\0';
213        }
214    }
215    *s = '\0';
216}
217
218static int __init do_mount_root(char *name, char *fs, int flags, void *data)
219{
220    int err = sys_mount(name, "/root", fs, flags, data);
221    if (err)
222        return err;
223
224    sys_chdir("/root");
225    ROOT_DEV = current->fs->pwd.mnt->mnt_sb->s_dev;
226    printk("VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
227           current->fs->pwd.mnt->mnt_sb->s_type->name,
228           current->fs->pwd.mnt->mnt_sb->s_flags & MS_RDONLY ?
229           " readonly" : "", MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
230    return 0;
231}
232
233void __init mount_block_root(char *name, int flags)
234{
235    char *fs_names = __getname_gfp(GFP_KERNEL
236        | __GFP_NOTRACK_FALSE_POSITIVE);
237    char *p;
238#ifdef CONFIG_BLOCK
239    char b[BDEVNAME_SIZE];
240#else
241    const char *b = name;
242#endif
243
244    get_fs_names(fs_names);
245retry:
246    for (p = fs_names; *p; p += strlen(p)+1) {
247        int err = do_mount_root(name, p, flags, root_mount_data);
248        switch (err) {
249            case 0:
250                goto out;
251            case -EACCES:
252                flags |= MS_RDONLY;
253                goto retry;
254            case -EINVAL:
255                continue;
256        }
257            /*
258         * Allow the user to distinguish between failed sys_open
259         * and bad superblock on root device.
260         * and give them a list of the available devices
261         */
262#ifdef CONFIG_BLOCK
263        __bdevname(ROOT_DEV, b);
264#endif
265        printk("VFS: Cannot open root device \"%s\" or %s\n",
266                root_device_name, b);
267        printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
268
269        printk_all_partitions();
270#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
271        printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
272               "explicit textual name for \"root=\" boot option.\n");
273#endif
274        panic("VFS: Unable to mount root fs on %s", b);
275    }
276
277    printk("List of all partitions:\n");
278    printk_all_partitions();
279    printk("No filesystem could mount root, tried: ");
280    for (p = fs_names; *p; p += strlen(p)+1)
281        printk(" %s", p);
282    printk("\n");
283#ifdef CONFIG_BLOCK
284    __bdevname(ROOT_DEV, b);
285#endif
286    panic("VFS: Unable to mount root fs on %s", b);
287out:
288    putname(fs_names);
289}
290 
291#ifdef CONFIG_ROOT_NFS
292static int __init mount_nfs_root(void)
293{
294    void *data = nfs_root_data();
295
296    create_dev("/dev/root", ROOT_DEV);
297    if (data &&
298        do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
299        return 1;
300    return 0;
301}
302#endif
303
304#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
305void __init change_floppy(char *fmt, ...)
306{
307    struct termios termios;
308    char buf[80];
309    char c;
310    int fd;
311    va_list args;
312    va_start(args, fmt);
313    vsprintf(buf, fmt, args);
314    va_end(args);
315    fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
316    if (fd >= 0) {
317        sys_ioctl(fd, FDEJECT, 0);
318        sys_close(fd);
319    }
320    printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
321    fd = sys_open("/dev/console", O_RDWR, 0);
322    if (fd >= 0) {
323        sys_ioctl(fd, TCGETS, (long)&termios);
324        termios.c_lflag &= ~ICANON;
325        sys_ioctl(fd, TCSETSF, (long)&termios);
326        sys_read(fd, &c, 1);
327        termios.c_lflag |= ICANON;
328        sys_ioctl(fd, TCSETSF, (long)&termios);
329        sys_close(fd);
330    }
331}
332#endif
333
334void __init mount_root(void)
335{
336#ifdef CONFIG_ROOT_NFS
337    if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
338        if (mount_nfs_root())
339            return;
340
341        printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
342        ROOT_DEV = Root_FD0;
343    }
344#endif
345#ifdef CONFIG_BLK_DEV_FD
346    if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
347        /* rd_doload is 2 for a dual initrd/ramload setup */
348        if (rd_doload==2) {
349            if (rd_load_disk(1)) {
350                ROOT_DEV = Root_RAM1;
351                root_device_name = NULL;
352            }
353        } else
354            change_floppy("root floppy");
355    }
356#endif
357#ifdef CONFIG_BLOCK
358    create_dev("/dev/root", ROOT_DEV);
359    mount_block_root("/dev/root", root_mountflags);
360#endif
361}
362
363/*
364 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
365 */
366void __init prepare_namespace(void)
367{
368    int is_floppy;
369
370    if (root_delay) {
371        printk(KERN_INFO "Waiting %dsec before mounting root device...\n",
372               root_delay);
373        ssleep(root_delay);
374    }
375
376    /*
377     * wait for the known devices to complete their probing
378     *
379     * Note: this is a potential source of long boot delays.
380     * For example, it is not atypical to wait 5 seconds here
381     * for the touchpad of a laptop to initialize.
382     */
383    wait_for_device_probe();
384
385    md_run_setup();
386
387    if (saved_root_name[0]) {
388        root_device_name = saved_root_name;
389        if (!strncmp(root_device_name, "mtd", 3) ||
390            !strncmp(root_device_name, "ubi", 3)) {
391            mount_block_root(root_device_name, root_mountflags);
392            goto out;
393        }
394        ROOT_DEV = name_to_dev_t(root_device_name);
395        if (strncmp(root_device_name, "/dev/", 5) == 0)
396            root_device_name += 5;
397    }
398
399    if (initrd_load())
400        goto out;
401
402    /* wait for any asynchronous scanning to complete */
403    if ((ROOT_DEV == 0) && root_wait) {
404        printk(KERN_INFO "Waiting for root device %s...\n",
405            saved_root_name);
406        while (driver_probe_done() != 0 ||
407            (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
408            msleep(100);
409        async_synchronize_full();
410    }
411
412    is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
413
414    if (is_floppy && rd_doload && rd_load_disk(0))
415        ROOT_DEV = Root_RAM0;
416
417    mount_root();
418out:
419    devtmpfs_mount("dev");
420    sys_mount(".", "/", NULL, MS_MOVE, NULL);
421    sys_chroot(".");
422}
423

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