Root/init/initramfs.c

1#include <linux/init.h>
2#include <linux/fs.h>
3#include <linux/slab.h>
4#include <linux/types.h>
5#include <linux/fcntl.h>
6#include <linux/delay.h>
7#include <linux/string.h>
8#include <linux/dirent.h>
9#include <linux/syscalls.h>
10#include <linux/utime.h>
11
12static __initdata char *message;
13static void __init error(char *x)
14{
15    if (!message)
16        message = x;
17}
18
19/* link hash */
20
21#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
22
23static __initdata struct hash {
24    int ino, minor, major;
25    mode_t mode;
26    struct hash *next;
27    char name[N_ALIGN(PATH_MAX)];
28} *head[32];
29
30static inline int hash(int major, int minor, int ino)
31{
32    unsigned long tmp = ino + minor + (major << 3);
33    tmp += tmp >> 5;
34    return tmp & 31;
35}
36
37static char __init *find_link(int major, int minor, int ino,
38                  mode_t mode, char *name)
39{
40    struct hash **p, *q;
41    for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
42        if ((*p)->ino != ino)
43            continue;
44        if ((*p)->minor != minor)
45            continue;
46        if ((*p)->major != major)
47            continue;
48        if (((*p)->mode ^ mode) & S_IFMT)
49            continue;
50        return (*p)->name;
51    }
52    q = kmalloc(sizeof(struct hash), GFP_KERNEL);
53    if (!q)
54        panic("can't allocate link hash entry");
55    q->major = major;
56    q->minor = minor;
57    q->ino = ino;
58    q->mode = mode;
59    strcpy(q->name, name);
60    q->next = NULL;
61    *p = q;
62    return NULL;
63}
64
65static void __init free_hash(void)
66{
67    struct hash **p, *q;
68    for (p = head; p < head + 32; p++) {
69        while (*p) {
70            q = *p;
71            *p = q->next;
72            kfree(q);
73        }
74    }
75}
76
77static long __init do_utime(char __user *filename, time_t mtime)
78{
79    struct timespec t[2];
80
81    t[0].tv_sec = mtime;
82    t[0].tv_nsec = 0;
83    t[1].tv_sec = mtime;
84    t[1].tv_nsec = 0;
85
86    return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
87}
88
89static __initdata LIST_HEAD(dir_list);
90struct dir_entry {
91    struct list_head list;
92    char *name;
93    time_t mtime;
94};
95
96static void __init dir_add(const char *name, time_t mtime)
97{
98    struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
99    if (!de)
100        panic("can't allocate dir_entry buffer");
101    INIT_LIST_HEAD(&de->list);
102    de->name = kstrdup(name, GFP_KERNEL);
103    de->mtime = mtime;
104    list_add(&de->list, &dir_list);
105}
106
107static void __init dir_utime(void)
108{
109    struct dir_entry *de, *tmp;
110    list_for_each_entry_safe(de, tmp, &dir_list, list) {
111        list_del(&de->list);
112        do_utime(de->name, de->mtime);
113        kfree(de->name);
114        kfree(de);
115    }
116}
117
118static __initdata time_t mtime;
119
120/* cpio header parsing */
121
122static __initdata unsigned long ino, major, minor, nlink;
123static __initdata mode_t mode;
124static __initdata unsigned long body_len, name_len;
125static __initdata uid_t uid;
126static __initdata gid_t gid;
127static __initdata unsigned rdev;
128
129static void __init parse_header(char *s)
130{
131    unsigned long parsed[12];
132    char buf[9];
133    int i;
134
135    buf[8] = '\0';
136    for (i = 0, s += 6; i < 12; i++, s += 8) {
137        memcpy(buf, s, 8);
138        parsed[i] = simple_strtoul(buf, NULL, 16);
139    }
140    ino = parsed[0];
141    mode = parsed[1];
142    uid = parsed[2];
143    gid = parsed[3];
144    nlink = parsed[4];
145    mtime = parsed[5];
146    body_len = parsed[6];
147    major = parsed[7];
148    minor = parsed[8];
149    rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
150    name_len = parsed[11];
151}
152
153/* FSM */
154
155static __initdata enum state {
156    Start,
157    Collect,
158    GotHeader,
159    SkipIt,
160    GotName,
161    CopyFile,
162    GotSymlink,
163    Reset
164} state, next_state;
165
166static __initdata char *victim;
167static __initdata unsigned count;
168static __initdata loff_t this_header, next_header;
169
170static inline void __init eat(unsigned n)
171{
172    victim += n;
173    this_header += n;
174    count -= n;
175}
176
177static __initdata char *vcollected;
178static __initdata char *collected;
179static __initdata int remains;
180static __initdata char *collect;
181
182static void __init read_into(char *buf, unsigned size, enum state next)
183{
184    if (count >= size) {
185        collected = victim;
186        eat(size);
187        state = next;
188    } else {
189        collect = collected = buf;
190        remains = size;
191        next_state = next;
192        state = Collect;
193    }
194}
195
196static __initdata char *header_buf, *symlink_buf, *name_buf;
197
198static int __init do_start(void)
199{
200    read_into(header_buf, 110, GotHeader);
201    return 0;
202}
203
204static int __init do_collect(void)
205{
206    unsigned n = remains;
207    if (count < n)
208        n = count;
209    memcpy(collect, victim, n);
210    eat(n);
211    collect += n;
212    if ((remains -= n) != 0)
213        return 1;
214    state = next_state;
215    return 0;
216}
217
218static int __init do_header(void)
219{
220    if (memcmp(collected, "070707", 6)==0) {
221        error("incorrect cpio method used: use -H newc option");
222        return 1;
223    }
224    if (memcmp(collected, "070701", 6)) {
225        error("no cpio magic");
226        return 1;
227    }
228    parse_header(collected);
229    next_header = this_header + N_ALIGN(name_len) + body_len;
230    next_header = (next_header + 3) & ~3;
231    state = SkipIt;
232    if (name_len <= 0 || name_len > PATH_MAX)
233        return 0;
234    if (S_ISLNK(mode)) {
235        if (body_len > PATH_MAX)
236            return 0;
237        collect = collected = symlink_buf;
238        remains = N_ALIGN(name_len) + body_len;
239        next_state = GotSymlink;
240        state = Collect;
241        return 0;
242    }
243    if (S_ISREG(mode) || !body_len)
244        read_into(name_buf, N_ALIGN(name_len), GotName);
245    return 0;
246}
247
248static int __init do_skip(void)
249{
250    if (this_header + count < next_header) {
251        eat(count);
252        return 1;
253    } else {
254        eat(next_header - this_header);
255        state = next_state;
256        return 0;
257    }
258}
259
260static int __init do_reset(void)
261{
262    while(count && *victim == '\0')
263        eat(1);
264    if (count && (this_header & 3))
265        error("broken padding");
266    return 1;
267}
268
269static int __init maybe_link(void)
270{
271    if (nlink >= 2) {
272        char *old = find_link(major, minor, ino, mode, collected);
273        if (old)
274            return (sys_link(old, collected) < 0) ? -1 : 1;
275    }
276    return 0;
277}
278
279static void __init clean_path(char *path, mode_t mode)
280{
281    struct stat st;
282
283    if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
284        if (S_ISDIR(st.st_mode))
285            sys_rmdir(path);
286        else
287            sys_unlink(path);
288    }
289}
290
291static __initdata int wfd;
292
293static int __init do_name(void)
294{
295    state = SkipIt;
296    next_state = Reset;
297    if (strcmp(collected, "TRAILER!!!") == 0) {
298        free_hash();
299        return 0;
300    }
301    clean_path(collected, mode);
302    if (S_ISREG(mode)) {
303        int ml = maybe_link();
304        if (ml >= 0) {
305            int openflags = O_WRONLY|O_CREAT;
306            if (ml != 1)
307                openflags |= O_TRUNC;
308            wfd = sys_open(collected, openflags, mode);
309
310            if (wfd >= 0) {
311                sys_fchown(wfd, uid, gid);
312                sys_fchmod(wfd, mode);
313                if (body_len)
314                    sys_ftruncate(wfd, body_len);
315                vcollected = kstrdup(collected, GFP_KERNEL);
316                state = CopyFile;
317            }
318        }
319    } else if (S_ISDIR(mode)) {
320        sys_mkdir(collected, mode);
321        sys_chown(collected, uid, gid);
322        sys_chmod(collected, mode);
323        dir_add(collected, mtime);
324    } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
325           S_ISFIFO(mode) || S_ISSOCK(mode)) {
326        if (maybe_link() == 0) {
327            sys_mknod(collected, mode, rdev);
328            sys_chown(collected, uid, gid);
329            sys_chmod(collected, mode);
330            do_utime(collected, mtime);
331        }
332    }
333    return 0;
334}
335
336static int __init do_copy(void)
337{
338    if (count >= body_len) {
339        sys_write(wfd, victim, body_len);
340        sys_close(wfd);
341        do_utime(vcollected, mtime);
342        kfree(vcollected);
343        eat(body_len);
344        state = SkipIt;
345        return 0;
346    } else {
347        sys_write(wfd, victim, count);
348        body_len -= count;
349        eat(count);
350        return 1;
351    }
352}
353
354static int __init do_symlink(void)
355{
356    collected[N_ALIGN(name_len) + body_len] = '\0';
357    clean_path(collected, 0);
358    sys_symlink(collected + N_ALIGN(name_len), collected);
359    sys_lchown(collected, uid, gid);
360    do_utime(collected, mtime);
361    state = SkipIt;
362    next_state = Reset;
363    return 0;
364}
365
366static __initdata int (*actions[])(void) = {
367    [Start] = do_start,
368    [Collect] = do_collect,
369    [GotHeader] = do_header,
370    [SkipIt] = do_skip,
371    [GotName] = do_name,
372    [CopyFile] = do_copy,
373    [GotSymlink] = do_symlink,
374    [Reset] = do_reset,
375};
376
377static int __init write_buffer(char *buf, unsigned len)
378{
379    count = len;
380    victim = buf;
381
382    while (!actions[state]())
383        ;
384    return len - count;
385}
386
387static int __init flush_buffer(void *bufv, unsigned len)
388{
389    char *buf = (char *) bufv;
390    int written;
391    int origLen = len;
392    if (message)
393        return -1;
394    while ((written = write_buffer(buf, len)) < len && !message) {
395        char c = buf[written];
396        if (c == '0') {
397            buf += written;
398            len -= written;
399            state = Start;
400        } else if (c == 0) {
401            buf += written;
402            len -= written;
403            state = Reset;
404        } else
405            error("junk in compressed archive");
406    }
407    return origLen;
408}
409
410static unsigned my_inptr; /* index of next byte to be processed in inbuf */
411
412#include <linux/decompress/generic.h>
413
414static char * __init unpack_to_rootfs(char *buf, unsigned len)
415{
416    int written, res;
417    decompress_fn decompress;
418    const char *compress_name;
419    static __initdata char msg_buf[64];
420
421    header_buf = kmalloc(110, GFP_KERNEL);
422    symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
423    name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
424
425    if (!header_buf || !symlink_buf || !name_buf)
426        panic("can't allocate buffers");
427
428    state = Start;
429    this_header = 0;
430    message = NULL;
431    while (!message && len) {
432        loff_t saved_offset = this_header;
433        if (*buf == '0' && !(this_header & 3)) {
434            state = Start;
435            written = write_buffer(buf, len);
436            buf += written;
437            len -= written;
438            continue;
439        }
440        if (!*buf) {
441            buf++;
442            len--;
443            this_header++;
444            continue;
445        }
446        this_header = 0;
447        decompress = decompress_method(buf, len, &compress_name);
448        if (decompress) {
449            res = decompress(buf, len, NULL, flush_buffer, NULL,
450                   &my_inptr, error);
451            if (res)
452                error("decompressor failed");
453        } else if (compress_name) {
454            if (!message) {
455                snprintf(msg_buf, sizeof msg_buf,
456                     "compression method %s not configured",
457                     compress_name);
458                message = msg_buf;
459            }
460        } else
461            error("junk in compressed archive");
462        if (state != Reset)
463            error("junk in compressed archive");
464        this_header = saved_offset + my_inptr;
465        buf += my_inptr;
466        len -= my_inptr;
467    }
468    dir_utime();
469    kfree(name_buf);
470    kfree(symlink_buf);
471    kfree(header_buf);
472    return message;
473}
474
475static int __initdata do_retain_initrd;
476
477static int __init retain_initrd_param(char *str)
478{
479    if (*str)
480        return 0;
481    do_retain_initrd = 1;
482    return 1;
483}
484__setup("retain_initrd", retain_initrd_param);
485
486extern char __initramfs_start[], __initramfs_end[];
487#include <linux/initrd.h>
488#include <linux/kexec.h>
489
490static void __init free_initrd(void)
491{
492#ifdef CONFIG_KEXEC
493    unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
494    unsigned long crashk_end = (unsigned long)__va(crashk_res.end);
495#endif
496    if (do_retain_initrd)
497        goto skip;
498
499#ifdef CONFIG_KEXEC
500    /*
501     * If the initrd region is overlapped with crashkernel reserved region,
502     * free only memory that is not part of crashkernel region.
503     */
504    if (initrd_start < crashk_end && initrd_end > crashk_start) {
505        /*
506         * Initialize initrd memory region since the kexec boot does
507         * not do.
508         */
509        memset((void *)initrd_start, 0, initrd_end - initrd_start);
510        if (initrd_start < crashk_start)
511            free_initrd_mem(initrd_start, crashk_start);
512        if (initrd_end > crashk_end)
513            free_initrd_mem(crashk_end, initrd_end);
514    } else
515#endif
516        free_initrd_mem(initrd_start, initrd_end);
517skip:
518    initrd_start = 0;
519    initrd_end = 0;
520}
521
522#ifdef CONFIG_BLK_DEV_RAM
523#define BUF_SIZE 1024
524static void __init clean_rootfs(void)
525{
526    int fd;
527    void *buf;
528    struct linux_dirent64 *dirp;
529    int num;
530
531    fd = sys_open("/", O_RDONLY, 0);
532    WARN_ON(fd < 0);
533    if (fd < 0)
534        return;
535    buf = kzalloc(BUF_SIZE, GFP_KERNEL);
536    WARN_ON(!buf);
537    if (!buf) {
538        sys_close(fd);
539        return;
540    }
541
542    dirp = buf;
543    num = sys_getdents64(fd, dirp, BUF_SIZE);
544    while (num > 0) {
545        while (num > 0) {
546            struct stat st;
547            int ret;
548
549            ret = sys_newlstat(dirp->d_name, &st);
550            WARN_ON_ONCE(ret);
551            if (!ret) {
552                if (S_ISDIR(st.st_mode))
553                    sys_rmdir(dirp->d_name);
554                else
555                    sys_unlink(dirp->d_name);
556            }
557
558            num -= dirp->d_reclen;
559            dirp = (void *)dirp + dirp->d_reclen;
560        }
561        dirp = buf;
562        memset(buf, 0, BUF_SIZE);
563        num = sys_getdents64(fd, dirp, BUF_SIZE);
564    }
565
566    sys_close(fd);
567    kfree(buf);
568}
569#endif
570
571static int __init populate_rootfs(void)
572{
573    char *err = unpack_to_rootfs(__initramfs_start,
574             __initramfs_end - __initramfs_start);
575    if (err)
576        panic(err); /* Failed to decompress INTERNAL initramfs */
577    if (initrd_start) {
578#ifdef CONFIG_BLK_DEV_RAM
579        int fd;
580        printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
581        err = unpack_to_rootfs((char *)initrd_start,
582            initrd_end - initrd_start);
583        if (!err) {
584            free_initrd();
585            return 0;
586        } else {
587            clean_rootfs();
588            unpack_to_rootfs(__initramfs_start,
589                 __initramfs_end - __initramfs_start);
590        }
591        printk(KERN_INFO "rootfs image is not initramfs (%s)"
592                "; looks like an initrd\n", err);
593        fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700);
594        if (fd >= 0) {
595            sys_write(fd, (char *)initrd_start,
596                    initrd_end - initrd_start);
597            sys_close(fd);
598            free_initrd();
599        }
600#else
601        printk(KERN_INFO "Unpacking initramfs...\n");
602        err = unpack_to_rootfs((char *)initrd_start,
603            initrd_end - initrd_start);
604        if (err)
605            printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
606        free_initrd();
607#endif
608    }
609    return 0;
610}
611rootfs_initcall(populate_rootfs);
612

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