Root/init/initramfs.c

1/*
2 * Many of the syscalls used in this file expect some of the arguments
3 * to be __user pointers not __kernel pointers. To limit the sparse
4 * noise, turn off sparse checking for this file.
5 */
6#ifdef __CHECKER__
7#undef __CHECKER__
8#warning "Sparse checking disabled for this file"
9#endif
10
11#include <linux/init.h>
12#include <linux/fs.h>
13#include <linux/slab.h>
14#include <linux/types.h>
15#include <linux/fcntl.h>
16#include <linux/delay.h>
17#include <linux/string.h>
18#include <linux/dirent.h>
19#include <linux/syscalls.h>
20#include <linux/utime.h>
21
22static __initdata char *message;
23static void __init error(char *x)
24{
25    if (!message)
26        message = x;
27}
28
29/* link hash */
30
31#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
32
33static __initdata struct hash {
34    int ino, minor, major;
35    umode_t mode;
36    struct hash *next;
37    char name[N_ALIGN(PATH_MAX)];
38} *head[32];
39
40static inline int hash(int major, int minor, int ino)
41{
42    unsigned long tmp = ino + minor + (major << 3);
43    tmp += tmp >> 5;
44    return tmp & 31;
45}
46
47static char __init *find_link(int major, int minor, int ino,
48                  umode_t mode, char *name)
49{
50    struct hash **p, *q;
51    for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
52        if ((*p)->ino != ino)
53            continue;
54        if ((*p)->minor != minor)
55            continue;
56        if ((*p)->major != major)
57            continue;
58        if (((*p)->mode ^ mode) & S_IFMT)
59            continue;
60        return (*p)->name;
61    }
62    q = kmalloc(sizeof(struct hash), GFP_KERNEL);
63    if (!q)
64        panic("can't allocate link hash entry");
65    q->major = major;
66    q->minor = minor;
67    q->ino = ino;
68    q->mode = mode;
69    strcpy(q->name, name);
70    q->next = NULL;
71    *p = q;
72    return NULL;
73}
74
75static void __init free_hash(void)
76{
77    struct hash **p, *q;
78    for (p = head; p < head + 32; p++) {
79        while (*p) {
80            q = *p;
81            *p = q->next;
82            kfree(q);
83        }
84    }
85}
86
87static long __init do_utime(char *filename, time_t mtime)
88{
89    struct timespec t[2];
90
91    t[0].tv_sec = mtime;
92    t[0].tv_nsec = 0;
93    t[1].tv_sec = mtime;
94    t[1].tv_nsec = 0;
95
96    return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
97}
98
99static __initdata LIST_HEAD(dir_list);
100struct dir_entry {
101    struct list_head list;
102    char *name;
103    time_t mtime;
104};
105
106static void __init dir_add(const char *name, time_t mtime)
107{
108    struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
109    if (!de)
110        panic("can't allocate dir_entry buffer");
111    INIT_LIST_HEAD(&de->list);
112    de->name = kstrdup(name, GFP_KERNEL);
113    de->mtime = mtime;
114    list_add(&de->list, &dir_list);
115}
116
117static void __init dir_utime(void)
118{
119    struct dir_entry *de, *tmp;
120    list_for_each_entry_safe(de, tmp, &dir_list, list) {
121        list_del(&de->list);
122        do_utime(de->name, de->mtime);
123        kfree(de->name);
124        kfree(de);
125    }
126}
127
128static __initdata time_t mtime;
129
130/* cpio header parsing */
131
132static __initdata unsigned long ino, major, minor, nlink;
133static __initdata umode_t mode;
134static __initdata unsigned long body_len, name_len;
135static __initdata uid_t uid;
136static __initdata gid_t gid;
137static __initdata unsigned rdev;
138
139static void __init parse_header(char *s)
140{
141    unsigned long parsed[12];
142    char buf[9];
143    int i;
144
145    buf[8] = '\0';
146    for (i = 0, s += 6; i < 12; i++, s += 8) {
147        memcpy(buf, s, 8);
148        parsed[i] = simple_strtoul(buf, NULL, 16);
149    }
150    ino = parsed[0];
151    mode = parsed[1];
152    uid = parsed[2];
153    gid = parsed[3];
154    nlink = parsed[4];
155    mtime = parsed[5];
156    body_len = parsed[6];
157    major = parsed[7];
158    minor = parsed[8];
159    rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
160    name_len = parsed[11];
161}
162
163/* FSM */
164
165static __initdata enum state {
166    Start,
167    Collect,
168    GotHeader,
169    SkipIt,
170    GotName,
171    CopyFile,
172    GotSymlink,
173    Reset
174} state, next_state;
175
176static __initdata char *victim;
177static __initdata unsigned count;
178static __initdata loff_t this_header, next_header;
179
180static inline void __init eat(unsigned n)
181{
182    victim += n;
183    this_header += n;
184    count -= n;
185}
186
187static __initdata char *vcollected;
188static __initdata char *collected;
189static __initdata int remains;
190static __initdata char *collect;
191
192static void __init read_into(char *buf, unsigned size, enum state next)
193{
194    if (count >= size) {
195        collected = victim;
196        eat(size);
197        state = next;
198    } else {
199        collect = collected = buf;
200        remains = size;
201        next_state = next;
202        state = Collect;
203    }
204}
205
206static __initdata char *header_buf, *symlink_buf, *name_buf;
207
208static int __init do_start(void)
209{
210    read_into(header_buf, 110, GotHeader);
211    return 0;
212}
213
214static int __init do_collect(void)
215{
216    unsigned n = remains;
217    if (count < n)
218        n = count;
219    memcpy(collect, victim, n);
220    eat(n);
221    collect += n;
222    if ((remains -= n) != 0)
223        return 1;
224    state = next_state;
225    return 0;
226}
227
228static int __init do_header(void)
229{
230    if (memcmp(collected, "070707", 6)==0) {
231        error("incorrect cpio method used: use -H newc option");
232        return 1;
233    }
234    if (memcmp(collected, "070701", 6)) {
235        error("no cpio magic");
236        return 1;
237    }
238    parse_header(collected);
239    next_header = this_header + N_ALIGN(name_len) + body_len;
240    next_header = (next_header + 3) & ~3;
241    state = SkipIt;
242    if (name_len <= 0 || name_len > PATH_MAX)
243        return 0;
244    if (S_ISLNK(mode)) {
245        if (body_len > PATH_MAX)
246            return 0;
247        collect = collected = symlink_buf;
248        remains = N_ALIGN(name_len) + body_len;
249        next_state = GotSymlink;
250        state = Collect;
251        return 0;
252    }
253    if (S_ISREG(mode) || !body_len)
254        read_into(name_buf, N_ALIGN(name_len), GotName);
255    return 0;
256}
257
258static int __init do_skip(void)
259{
260    if (this_header + count < next_header) {
261        eat(count);
262        return 1;
263    } else {
264        eat(next_header - this_header);
265        state = next_state;
266        return 0;
267    }
268}
269
270static int __init do_reset(void)
271{
272    while(count && *victim == '\0')
273        eat(1);
274    if (count && (this_header & 3))
275        error("broken padding");
276    return 1;
277}
278
279static int __init maybe_link(void)
280{
281    if (nlink >= 2) {
282        char *old = find_link(major, minor, ino, mode, collected);
283        if (old)
284            return (sys_link(old, collected) < 0) ? -1 : 1;
285    }
286    return 0;
287}
288
289static void __init clean_path(char *path, umode_t mode)
290{
291    struct stat st;
292
293    if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
294        if (S_ISDIR(st.st_mode))
295            sys_rmdir(path);
296        else
297            sys_unlink(path);
298    }
299}
300
301static __initdata int wfd;
302
303static int __init do_name(void)
304{
305    state = SkipIt;
306    next_state = Reset;
307    if (strcmp(collected, "TRAILER!!!") == 0) {
308        free_hash();
309        return 0;
310    }
311    clean_path(collected, mode);
312    if (S_ISREG(mode)) {
313        int ml = maybe_link();
314        if (ml >= 0) {
315            int openflags = O_WRONLY|O_CREAT;
316            if (ml != 1)
317                openflags |= O_TRUNC;
318            wfd = sys_open(collected, openflags, mode);
319
320            if (wfd >= 0) {
321                sys_fchown(wfd, uid, gid);
322                sys_fchmod(wfd, mode);
323                if (body_len)
324                    sys_ftruncate(wfd, body_len);
325                vcollected = kstrdup(collected, GFP_KERNEL);
326                state = CopyFile;
327            }
328        }
329    } else if (S_ISDIR(mode)) {
330        sys_mkdir(collected, mode);
331        sys_chown(collected, uid, gid);
332        sys_chmod(collected, mode);
333        dir_add(collected, mtime);
334    } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
335           S_ISFIFO(mode) || S_ISSOCK(mode)) {
336        if (maybe_link() == 0) {
337            sys_mknod(collected, mode, rdev);
338            sys_chown(collected, uid, gid);
339            sys_chmod(collected, mode);
340            do_utime(collected, mtime);
341        }
342    }
343    return 0;
344}
345
346static int __init do_copy(void)
347{
348    if (count >= body_len) {
349        sys_write(wfd, victim, body_len);
350        sys_close(wfd);
351        do_utime(vcollected, mtime);
352        kfree(vcollected);
353        eat(body_len);
354        state = SkipIt;
355        return 0;
356    } else {
357        sys_write(wfd, victim, count);
358        body_len -= count;
359        eat(count);
360        return 1;
361    }
362}
363
364static int __init do_symlink(void)
365{
366    collected[N_ALIGN(name_len) + body_len] = '\0';
367    clean_path(collected, 0);
368    sys_symlink(collected + N_ALIGN(name_len), collected);
369    sys_lchown(collected, uid, gid);
370    do_utime(collected, mtime);
371    state = SkipIt;
372    next_state = Reset;
373    return 0;
374}
375
376static __initdata int (*actions[])(void) = {
377    [Start] = do_start,
378    [Collect] = do_collect,
379    [GotHeader] = do_header,
380    [SkipIt] = do_skip,
381    [GotName] = do_name,
382    [CopyFile] = do_copy,
383    [GotSymlink] = do_symlink,
384    [Reset] = do_reset,
385};
386
387static int __init write_buffer(char *buf, unsigned len)
388{
389    count = len;
390    victim = buf;
391
392    while (!actions[state]())
393        ;
394    return len - count;
395}
396
397static int __init flush_buffer(void *bufv, unsigned len)
398{
399    char *buf = (char *) bufv;
400    int written;
401    int origLen = len;
402    if (message)
403        return -1;
404    while ((written = write_buffer(buf, len)) < len && !message) {
405        char c = buf[written];
406        if (c == '0') {
407            buf += written;
408            len -= written;
409            state = Start;
410        } else if (c == 0) {
411            buf += written;
412            len -= written;
413            state = Reset;
414        } else
415            error("junk in compressed archive");
416    }
417    return origLen;
418}
419
420static unsigned my_inptr; /* index of next byte to be processed in inbuf */
421
422#include <linux/decompress/generic.h>
423
424static char * __init unpack_to_rootfs(char *buf, unsigned len)
425{
426    int written, res;
427    decompress_fn decompress;
428    const char *compress_name;
429    static __initdata char msg_buf[64];
430
431    header_buf = kmalloc(110, GFP_KERNEL);
432    symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
433    name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
434
435    if (!header_buf || !symlink_buf || !name_buf)
436        panic("can't allocate buffers");
437
438    state = Start;
439    this_header = 0;
440    message = NULL;
441    while (!message && len) {
442        loff_t saved_offset = this_header;
443        if (*buf == '0' && !(this_header & 3)) {
444            state = Start;
445            written = write_buffer(buf, len);
446            buf += written;
447            len -= written;
448            continue;
449        }
450        if (!*buf) {
451            buf++;
452            len--;
453            this_header++;
454            continue;
455        }
456        this_header = 0;
457        decompress = decompress_method(buf, len, &compress_name);
458        if (decompress) {
459            res = decompress(buf, len, NULL, flush_buffer, NULL,
460                   &my_inptr, error);
461            if (res)
462                error("decompressor failed");
463        } else if (compress_name) {
464            if (!message) {
465                snprintf(msg_buf, sizeof msg_buf,
466                     "compression method %s not configured",
467                     compress_name);
468                message = msg_buf;
469            }
470        } else
471            error("junk in compressed archive");
472        if (state != Reset)
473            error("junk in compressed archive");
474        this_header = saved_offset + my_inptr;
475        buf += my_inptr;
476        len -= my_inptr;
477    }
478    dir_utime();
479    kfree(name_buf);
480    kfree(symlink_buf);
481    kfree(header_buf);
482    return message;
483}
484
485static int __initdata do_retain_initrd;
486
487static int __init retain_initrd_param(char *str)
488{
489    if (*str)
490        return 0;
491    do_retain_initrd = 1;
492    return 1;
493}
494__setup("retain_initrd", retain_initrd_param);
495
496extern char __initramfs_start[];
497extern unsigned long __initramfs_size;
498#include <linux/initrd.h>
499#include <linux/kexec.h>
500
501static void __init free_initrd(void)
502{
503#ifdef CONFIG_KEXEC
504    unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
505    unsigned long crashk_end = (unsigned long)__va(crashk_res.end);
506#endif
507    if (do_retain_initrd)
508        goto skip;
509
510#ifdef CONFIG_KEXEC
511    /*
512     * If the initrd region is overlapped with crashkernel reserved region,
513     * free only memory that is not part of crashkernel region.
514     */
515    if (initrd_start < crashk_end && initrd_end > crashk_start) {
516        /*
517         * Initialize initrd memory region since the kexec boot does
518         * not do.
519         */
520        memset((void *)initrd_start, 0, initrd_end - initrd_start);
521        if (initrd_start < crashk_start)
522            free_initrd_mem(initrd_start, crashk_start);
523        if (initrd_end > crashk_end)
524            free_initrd_mem(crashk_end, initrd_end);
525    } else
526#endif
527        free_initrd_mem(initrd_start, initrd_end);
528skip:
529    initrd_start = 0;
530    initrd_end = 0;
531}
532
533#ifdef CONFIG_BLK_DEV_RAM
534#define BUF_SIZE 1024
535static void __init clean_rootfs(void)
536{
537    int fd;
538    void *buf;
539    struct linux_dirent64 *dirp;
540    int num;
541
542    fd = sys_open("/", O_RDONLY, 0);
543    WARN_ON(fd < 0);
544    if (fd < 0)
545        return;
546    buf = kzalloc(BUF_SIZE, GFP_KERNEL);
547    WARN_ON(!buf);
548    if (!buf) {
549        sys_close(fd);
550        return;
551    }
552
553    dirp = buf;
554    num = sys_getdents64(fd, dirp, BUF_SIZE);
555    while (num > 0) {
556        while (num > 0) {
557            struct stat st;
558            int ret;
559
560            ret = sys_newlstat(dirp->d_name, &st);
561            WARN_ON_ONCE(ret);
562            if (!ret) {
563                if (S_ISDIR(st.st_mode))
564                    sys_rmdir(dirp->d_name);
565                else
566                    sys_unlink(dirp->d_name);
567            }
568
569            num -= dirp->d_reclen;
570            dirp = (void *)dirp + dirp->d_reclen;
571        }
572        dirp = buf;
573        memset(buf, 0, BUF_SIZE);
574        num = sys_getdents64(fd, dirp, BUF_SIZE);
575    }
576
577    sys_close(fd);
578    kfree(buf);
579}
580#endif
581
582static int __init populate_rootfs(void)
583{
584    char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
585    if (err)
586        panic(err); /* Failed to decompress INTERNAL initramfs */
587    if (initrd_start) {
588#ifdef CONFIG_BLK_DEV_RAM
589        int fd;
590        printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
591        err = unpack_to_rootfs((char *)initrd_start,
592            initrd_end - initrd_start);
593        if (!err) {
594            free_initrd();
595            return 0;
596        } else {
597            clean_rootfs();
598            unpack_to_rootfs(__initramfs_start, __initramfs_size);
599        }
600        printk(KERN_INFO "rootfs image is not initramfs (%s)"
601                "; looks like an initrd\n", err);
602        fd = sys_open("/initrd.image",
603                  O_WRONLY|O_CREAT, 0700);
604        if (fd >= 0) {
605            sys_write(fd, (char *)initrd_start,
606                    initrd_end - initrd_start);
607            sys_close(fd);
608            free_initrd();
609        }
610#else
611        printk(KERN_INFO "Unpacking initramfs...\n");
612        err = unpack_to_rootfs((char *)initrd_start,
613            initrd_end - initrd_start);
614        if (err)
615            printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
616        free_initrd();
617#endif
618    }
619    return 0;
620}
621rootfs_initcall(populate_rootfs);
622

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