Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm...
[linux-3.10.git] / 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
22 static __initdata char *message;
23 static 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
33 static __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
40 static 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
47 static 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
75 static 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
87 static 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
99 static __initdata LIST_HEAD(dir_list);
100 struct dir_entry {
101         struct list_head list;
102         char *name;
103         time_t mtime;
104 };
105
106 static 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
117 static 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
128 static __initdata time_t mtime;
129
130 /* cpio header parsing */
131
132 static __initdata unsigned long ino, major, minor, nlink;
133 static __initdata umode_t mode;
134 static __initdata unsigned long body_len, name_len;
135 static __initdata uid_t uid;
136 static __initdata gid_t gid;
137 static __initdata unsigned rdev;
138
139 static 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
165 static __initdata enum state {
166         Start,
167         Collect,
168         GotHeader,
169         SkipIt,
170         GotName,
171         CopyFile,
172         GotSymlink,
173         Reset
174 } state, next_state;
175
176 static __initdata char *victim;
177 static __initdata unsigned count;
178 static __initdata loff_t this_header, next_header;
179
180 static inline void __init eat(unsigned n)
181 {
182         victim += n;
183         this_header += n;
184         count -= n;
185 }
186
187 static __initdata char *vcollected;
188 static __initdata char *collected;
189 static __initdata int remains;
190 static __initdata char *collect;
191
192 static 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
206 static __initdata char *header_buf, *symlink_buf, *name_buf;
207
208 static int __init do_start(void)
209 {
210         read_into(header_buf, 110, GotHeader);
211         return 0;
212 }
213
214 static 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
228 static 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
258 static 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
270 static 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
279 static 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
289 static 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
301 static __initdata int wfd;
302
303 static 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
346 static 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
364 static 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
376 static __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
387 static 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
397 static 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
420 static unsigned my_inptr;   /* index of next byte to be processed in inbuf */
421
422 #include <linux/decompress/generic.h>
423
424 static 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
485 static int __initdata do_retain_initrd;
486
487 static 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
496 extern char __initramfs_start[];
497 extern unsigned long __initramfs_size;
498 #include <linux/initrd.h>
499 #include <linux/kexec.h>
500
501 static 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);
528 skip:
529         initrd_start = 0;
530         initrd_end = 0;
531 }
532
533 #ifdef CONFIG_BLK_DEV_RAM
534 #define BUF_SIZE 1024
535 static 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
582 static 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                         goto done;
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         done:
611 #else
612                 printk(KERN_INFO "Unpacking initramfs...\n");
613                 err = unpack_to_rootfs((char *)initrd_start,
614                         initrd_end - initrd_start);
615                 if (err)
616                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
617                 free_initrd();
618 #endif
619                 /*
620                  * Try loading default modules from initramfs.  This gives
621                  * us a chance to load before device_initcalls.
622                  */
623                 load_default_modules();
624         }
625         return 0;
626 }
627 rootfs_initcall(populate_rootfs);