bzip2/lzma: make flush_buffer() unconditional
[linux-2.6.git] / 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/syscalls.h>
9 #include <linux/utime.h>
10
11 static __initdata char *message;
12 static void __init error(char *x)
13 {
14         if (!message)
15                 message = x;
16 }
17
18 /* link hash */
19
20 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
21
22 static __initdata struct hash {
23         int ino, minor, major;
24         mode_t mode;
25         struct hash *next;
26         char name[N_ALIGN(PATH_MAX)];
27 } *head[32];
28
29 static inline int hash(int major, int minor, int ino)
30 {
31         unsigned long tmp = ino + minor + (major << 3);
32         tmp += tmp >> 5;
33         return tmp & 31;
34 }
35
36 static char __init *find_link(int major, int minor, int ino,
37                               mode_t mode, char *name)
38 {
39         struct hash **p, *q;
40         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
41                 if ((*p)->ino != ino)
42                         continue;
43                 if ((*p)->minor != minor)
44                         continue;
45                 if ((*p)->major != major)
46                         continue;
47                 if (((*p)->mode ^ mode) & S_IFMT)
48                         continue;
49                 return (*p)->name;
50         }
51         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
52         if (!q)
53                 panic("can't allocate link hash entry");
54         q->major = major;
55         q->minor = minor;
56         q->ino = ino;
57         q->mode = mode;
58         strcpy(q->name, name);
59         q->next = NULL;
60         *p = q;
61         return NULL;
62 }
63
64 static void __init free_hash(void)
65 {
66         struct hash **p, *q;
67         for (p = head; p < head + 32; p++) {
68                 while (*p) {
69                         q = *p;
70                         *p = q->next;
71                         kfree(q);
72                 }
73         }
74 }
75
76 static long __init do_utime(char __user *filename, time_t mtime)
77 {
78         struct timespec t[2];
79
80         t[0].tv_sec = mtime;
81         t[0].tv_nsec = 0;
82         t[1].tv_sec = mtime;
83         t[1].tv_nsec = 0;
84
85         return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
86 }
87
88 static __initdata LIST_HEAD(dir_list);
89 struct dir_entry {
90         struct list_head list;
91         char *name;
92         time_t mtime;
93 };
94
95 static void __init dir_add(const char *name, time_t mtime)
96 {
97         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
98         if (!de)
99                 panic("can't allocate dir_entry buffer");
100         INIT_LIST_HEAD(&de->list);
101         de->name = kstrdup(name, GFP_KERNEL);
102         de->mtime = mtime;
103         list_add(&de->list, &dir_list);
104 }
105
106 static void __init dir_utime(void)
107 {
108         struct dir_entry *de, *tmp;
109         list_for_each_entry_safe(de, tmp, &dir_list, list) {
110                 list_del(&de->list);
111                 do_utime(de->name, de->mtime);
112                 kfree(de->name);
113                 kfree(de);
114         }
115 }
116
117 static __initdata time_t mtime;
118
119 /* cpio header parsing */
120
121 static __initdata unsigned long ino, major, minor, nlink;
122 static __initdata mode_t mode;
123 static __initdata unsigned long body_len, name_len;
124 static __initdata uid_t uid;
125 static __initdata gid_t gid;
126 static __initdata unsigned rdev;
127
128 static void __init parse_header(char *s)
129 {
130         unsigned long parsed[12];
131         char buf[9];
132         int i;
133
134         buf[8] = '\0';
135         for (i = 0, s += 6; i < 12; i++, s += 8) {
136                 memcpy(buf, s, 8);
137                 parsed[i] = simple_strtoul(buf, NULL, 16);
138         }
139         ino = parsed[0];
140         mode = parsed[1];
141         uid = parsed[2];
142         gid = parsed[3];
143         nlink = parsed[4];
144         mtime = parsed[5];
145         body_len = parsed[6];
146         major = parsed[7];
147         minor = parsed[8];
148         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
149         name_len = parsed[11];
150 }
151
152 /* FSM */
153
154 static __initdata enum state {
155         Start,
156         Collect,
157         GotHeader,
158         SkipIt,
159         GotName,
160         CopyFile,
161         GotSymlink,
162         Reset
163 } state, next_state;
164
165 static __initdata char *victim;
166 static __initdata unsigned count;
167 static __initdata loff_t this_header, next_header;
168
169 static __initdata int dry_run;
170
171 static inline void __init eat(unsigned n)
172 {
173         victim += n;
174         this_header += n;
175         count -= n;
176 }
177
178 static __initdata char *vcollected;
179 static __initdata char *collected;
180 static __initdata int remains;
181 static __initdata char *collect;
182
183 static void __init read_into(char *buf, unsigned size, enum state next)
184 {
185         if (count >= size) {
186                 collected = victim;
187                 eat(size);
188                 state = next;
189         } else {
190                 collect = collected = buf;
191                 remains = size;
192                 next_state = next;
193                 state = Collect;
194         }
195 }
196
197 static __initdata char *header_buf, *symlink_buf, *name_buf;
198
199 static int __init do_start(void)
200 {
201         read_into(header_buf, 110, GotHeader);
202         return 0;
203 }
204
205 static int __init do_collect(void)
206 {
207         unsigned n = remains;
208         if (count < n)
209                 n = count;
210         memcpy(collect, victim, n);
211         eat(n);
212         collect += n;
213         if ((remains -= n) != 0)
214                 return 1;
215         state = next_state;
216         return 0;
217 }
218
219 static int __init do_header(void)
220 {
221         if (memcmp(collected, "070707", 6)==0) {
222                 error("incorrect cpio method used: use -H newc option");
223                 return 1;
224         }
225         if (memcmp(collected, "070701", 6)) {
226                 error("no cpio magic");
227                 return 1;
228         }
229         parse_header(collected);
230         next_header = this_header + N_ALIGN(name_len) + body_len;
231         next_header = (next_header + 3) & ~3;
232         if (dry_run) {
233                 read_into(name_buf, N_ALIGN(name_len), GotName);
234                 return 0;
235         }
236         state = SkipIt;
237         if (name_len <= 0 || name_len > PATH_MAX)
238                 return 0;
239         if (S_ISLNK(mode)) {
240                 if (body_len > PATH_MAX)
241                         return 0;
242                 collect = collected = symlink_buf;
243                 remains = N_ALIGN(name_len) + body_len;
244                 next_state = GotSymlink;
245                 state = Collect;
246                 return 0;
247         }
248         if (S_ISREG(mode) || !body_len)
249                 read_into(name_buf, N_ALIGN(name_len), GotName);
250         return 0;
251 }
252
253 static int __init do_skip(void)
254 {
255         if (this_header + count < next_header) {
256                 eat(count);
257                 return 1;
258         } else {
259                 eat(next_header - this_header);
260                 state = next_state;
261                 return 0;
262         }
263 }
264
265 static int __init do_reset(void)
266 {
267         while(count && *victim == '\0')
268                 eat(1);
269         if (count && (this_header & 3))
270                 error("broken padding");
271         return 1;
272 }
273
274 static int __init maybe_link(void)
275 {
276         if (nlink >= 2) {
277                 char *old = find_link(major, minor, ino, mode, collected);
278                 if (old)
279                         return (sys_link(old, collected) < 0) ? -1 : 1;
280         }
281         return 0;
282 }
283
284 static void __init clean_path(char *path, mode_t mode)
285 {
286         struct stat st;
287
288         if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
289                 if (S_ISDIR(st.st_mode))
290                         sys_rmdir(path);
291                 else
292                         sys_unlink(path);
293         }
294 }
295
296 static __initdata int wfd;
297
298 static int __init do_name(void)
299 {
300         state = SkipIt;
301         next_state = Reset;
302         if (strcmp(collected, "TRAILER!!!") == 0) {
303                 free_hash();
304                 return 0;
305         }
306         if (dry_run)
307                 return 0;
308         clean_path(collected, mode);
309         if (S_ISREG(mode)) {
310                 int ml = maybe_link();
311                 if (ml >= 0) {
312                         int openflags = O_WRONLY|O_CREAT;
313                         if (ml != 1)
314                                 openflags |= O_TRUNC;
315                         wfd = sys_open(collected, openflags, mode);
316
317                         if (wfd >= 0) {
318                                 sys_fchown(wfd, uid, gid);
319                                 sys_fchmod(wfd, mode);
320                                 sys_ftruncate(wfd, body_len);
321                                 vcollected = kstrdup(collected, GFP_KERNEL);
322                                 state = CopyFile;
323                         }
324                 }
325         } else if (S_ISDIR(mode)) {
326                 sys_mkdir(collected, mode);
327                 sys_chown(collected, uid, gid);
328                 sys_chmod(collected, mode);
329                 dir_add(collected, mtime);
330         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
331                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
332                 if (maybe_link() == 0) {
333                         sys_mknod(collected, mode, rdev);
334                         sys_chown(collected, uid, gid);
335                         sys_chmod(collected, mode);
336                         do_utime(collected, mtime);
337                 }
338         }
339         return 0;
340 }
341
342 static int __init do_copy(void)
343 {
344         if (count >= body_len) {
345                 sys_write(wfd, victim, body_len);
346                 sys_close(wfd);
347                 do_utime(vcollected, mtime);
348                 kfree(vcollected);
349                 eat(body_len);
350                 state = SkipIt;
351                 return 0;
352         } else {
353                 sys_write(wfd, victim, count);
354                 body_len -= count;
355                 eat(count);
356                 return 1;
357         }
358 }
359
360 static int __init do_symlink(void)
361 {
362         collected[N_ALIGN(name_len) + body_len] = '\0';
363         clean_path(collected, 0);
364         sys_symlink(collected + N_ALIGN(name_len), collected);
365         sys_lchown(collected, uid, gid);
366         do_utime(collected, mtime);
367         state = SkipIt;
368         next_state = Reset;
369         return 0;
370 }
371
372 static __initdata int (*actions[])(void) = {
373         [Start]         = do_start,
374         [Collect]       = do_collect,
375         [GotHeader]     = do_header,
376         [SkipIt]        = do_skip,
377         [GotName]       = do_name,
378         [CopyFile]      = do_copy,
379         [GotSymlink]    = do_symlink,
380         [Reset]         = do_reset,
381 };
382
383 static int __init write_buffer(char *buf, unsigned len)
384 {
385         count = len;
386         victim = buf;
387
388         while (!actions[state]())
389                 ;
390         return len - count;
391 }
392
393 static int __init flush_buffer(void *bufv, unsigned len)
394 {
395         char *buf = (char *) bufv;
396         int written;
397         int origLen = len;
398         if (message)
399                 return -1;
400         while ((written = write_buffer(buf, len)) < len && !message) {
401                 char c = buf[written];
402                 if (c == '0') {
403                         buf += written;
404                         len -= written;
405                         state = Start;
406                 } else if (c == 0) {
407                         buf += written;
408                         len -= written;
409                         state = Reset;
410                 } else
411                         error("junk in compressed archive");
412         }
413         return origLen;
414 }
415
416 static unsigned my_inptr;   /* index of next byte to be processed in inbuf */
417
418 #include <linux/decompress/generic.h>
419
420 static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
421 {
422         int written;
423         decompress_fn decompress;
424
425         dry_run = check_only;
426         header_buf = kmalloc(110, GFP_KERNEL);
427         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
428         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
429
430         if (!header_buf || !symlink_buf || !name_buf)
431                 panic("can't allocate buffers");
432
433         state = Start;
434         this_header = 0;
435         message = NULL;
436         while (!message && len) {
437                 loff_t saved_offset = this_header;
438                 if (*buf == '0' && !(this_header & 3)) {
439                         state = Start;
440                         written = write_buffer(buf, len);
441                         buf += written;
442                         len -= written;
443                         continue;
444                 }
445                 if (!*buf) {
446                         buf++;
447                         len--;
448                         this_header++;
449                         continue;
450                 }
451                 this_header = 0;
452                 decompress = decompress_method(buf, len, NULL);
453                 if (decompress)
454                         decompress(buf, len, NULL, flush_buffer, NULL,
455                                    &my_inptr, error);
456                 if (state != Reset)
457                         error("junk in compressed archive");
458                 this_header = saved_offset + my_inptr;
459                 buf += my_inptr;
460                 len -= my_inptr;
461         }
462         dir_utime();
463         kfree(name_buf);
464         kfree(symlink_buf);
465         kfree(header_buf);
466         return message;
467 }
468
469 static int __initdata do_retain_initrd;
470
471 static int __init retain_initrd_param(char *str)
472 {
473         if (*str)
474                 return 0;
475         do_retain_initrd = 1;
476         return 1;
477 }
478 __setup("retain_initrd", retain_initrd_param);
479
480 extern char __initramfs_start[], __initramfs_end[];
481 #include <linux/initrd.h>
482 #include <linux/kexec.h>
483
484 static void __init free_initrd(void)
485 {
486 #ifdef CONFIG_KEXEC
487         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
488         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
489 #endif
490         if (do_retain_initrd)
491                 goto skip;
492
493 #ifdef CONFIG_KEXEC
494         /*
495          * If the initrd region is overlapped with crashkernel reserved region,
496          * free only memory that is not part of crashkernel region.
497          */
498         if (initrd_start < crashk_end && initrd_end > crashk_start) {
499                 /*
500                  * Initialize initrd memory region since the kexec boot does
501                  * not do.
502                  */
503                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
504                 if (initrd_start < crashk_start)
505                         free_initrd_mem(initrd_start, crashk_start);
506                 if (initrd_end > crashk_end)
507                         free_initrd_mem(crashk_end, initrd_end);
508         } else
509 #endif
510                 free_initrd_mem(initrd_start, initrd_end);
511 skip:
512         initrd_start = 0;
513         initrd_end = 0;
514 }
515
516 static int __init populate_rootfs(void)
517 {
518         char *err = unpack_to_rootfs(__initramfs_start,
519                          __initramfs_end - __initramfs_start, 0);
520         if (err)
521                 panic(err);
522         if (initrd_start) {
523 #ifdef CONFIG_BLK_DEV_RAM
524                 int fd;
525                 printk(KERN_INFO "checking if image is initramfs...");
526                 err = unpack_to_rootfs((char *)initrd_start,
527                         initrd_end - initrd_start, 1);
528                 if (!err) {
529                         printk(" it is\n");
530                         unpack_to_rootfs((char *)initrd_start,
531                                 initrd_end - initrd_start, 0);
532                         free_initrd();
533                         return 0;
534                 }
535                 printk("it isn't (%s); looks like an initrd\n", err);
536                 fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700);
537                 if (fd >= 0) {
538                         sys_write(fd, (char *)initrd_start,
539                                         initrd_end - initrd_start);
540                         sys_close(fd);
541                         free_initrd();
542                 }
543 #else
544                 printk(KERN_INFO "Unpacking initramfs...");
545                 err = unpack_to_rootfs((char *)initrd_start,
546                         initrd_end - initrd_start, 0);
547                 if (err)
548                         panic(err);
549                 printk(" done\n");
550                 free_initrd();
551 #endif
552         }
553         return 0;
554 }
555 rootfs_initcall(populate_rootfs);