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TOMOYO Linux Cross Reference
Linux/init/initramfs.c

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  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 #include <linux/file.h>
 22 
 23 static ssize_t __init xwrite(int fd, const char *p, size_t count)
 24 {
 25         ssize_t out = 0;
 26 
 27         /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
 28         while (count) {
 29                 ssize_t rv = sys_write(fd, p, count);
 30 
 31                 if (rv < 0) {
 32                         if (rv == -EINTR || rv == -EAGAIN)
 33                                 continue;
 34                         return out ? out : rv;
 35                 } else if (rv == 0)
 36                         break;
 37 
 38                 p += rv;
 39                 out += rv;
 40                 count -= rv;
 41         }
 42 
 43         return out;
 44 }
 45 
 46 static __initdata char *message;
 47 static void __init error(char *x)
 48 {
 49         if (!message)
 50                 message = x;
 51 }
 52 
 53 /* link hash */
 54 
 55 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
 56 
 57 static __initdata struct hash {
 58         int ino, minor, major;
 59         umode_t mode;
 60         struct hash *next;
 61         char name[N_ALIGN(PATH_MAX)];
 62 } *head[32];
 63 
 64 static inline int hash(int major, int minor, int ino)
 65 {
 66         unsigned long tmp = ino + minor + (major << 3);
 67         tmp += tmp >> 5;
 68         return tmp & 31;
 69 }
 70 
 71 static char __init *find_link(int major, int minor, int ino,
 72                               umode_t mode, char *name)
 73 {
 74         struct hash **p, *q;
 75         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
 76                 if ((*p)->ino != ino)
 77                         continue;
 78                 if ((*p)->minor != minor)
 79                         continue;
 80                 if ((*p)->major != major)
 81                         continue;
 82                 if (((*p)->mode ^ mode) & S_IFMT)
 83                         continue;
 84                 return (*p)->name;
 85         }
 86         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
 87         if (!q)
 88                 panic("can't allocate link hash entry");
 89         q->major = major;
 90         q->minor = minor;
 91         q->ino = ino;
 92         q->mode = mode;
 93         strcpy(q->name, name);
 94         q->next = NULL;
 95         *p = q;
 96         return NULL;
 97 }
 98 
 99 static void __init free_hash(void)
100 {
101         struct hash **p, *q;
102         for (p = head; p < head + 32; p++) {
103                 while (*p) {
104                         q = *p;
105                         *p = q->next;
106                         kfree(q);
107                 }
108         }
109 }
110 
111 static long __init do_utime(char *filename, time_t mtime)
112 {
113         struct timespec t[2];
114 
115         t[0].tv_sec = mtime;
116         t[0].tv_nsec = 0;
117         t[1].tv_sec = mtime;
118         t[1].tv_nsec = 0;
119 
120         return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
121 }
122 
123 static __initdata LIST_HEAD(dir_list);
124 struct dir_entry {
125         struct list_head list;
126         char *name;
127         time_t mtime;
128 };
129 
130 static void __init dir_add(const char *name, time_t mtime)
131 {
132         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
133         if (!de)
134                 panic("can't allocate dir_entry buffer");
135         INIT_LIST_HEAD(&de->list);
136         de->name = kstrdup(name, GFP_KERNEL);
137         de->mtime = mtime;
138         list_add(&de->list, &dir_list);
139 }
140 
141 static void __init dir_utime(void)
142 {
143         struct dir_entry *de, *tmp;
144         list_for_each_entry_safe(de, tmp, &dir_list, list) {
145                 list_del(&de->list);
146                 do_utime(de->name, de->mtime);
147                 kfree(de->name);
148                 kfree(de);
149         }
150 }
151 
152 static __initdata time_t mtime;
153 
154 /* cpio header parsing */
155 
156 static __initdata unsigned long ino, major, minor, nlink;
157 static __initdata umode_t mode;
158 static __initdata unsigned long body_len, name_len;
159 static __initdata uid_t uid;
160 static __initdata gid_t gid;
161 static __initdata unsigned rdev;
162 
163 static void __init parse_header(char *s)
164 {
165         unsigned long parsed[12];
166         char buf[9];
167         int i;
168 
169         buf[8] = '\0';
170         for (i = 0, s += 6; i < 12; i++, s += 8) {
171                 memcpy(buf, s, 8);
172                 parsed[i] = simple_strtoul(buf, NULL, 16);
173         }
174         ino = parsed[0];
175         mode = parsed[1];
176         uid = parsed[2];
177         gid = parsed[3];
178         nlink = parsed[4];
179         mtime = parsed[5];
180         body_len = parsed[6];
181         major = parsed[7];
182         minor = parsed[8];
183         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
184         name_len = parsed[11];
185 }
186 
187 /* FSM */
188 
189 static __initdata enum state {
190         Start,
191         Collect,
192         GotHeader,
193         SkipIt,
194         GotName,
195         CopyFile,
196         GotSymlink,
197         Reset
198 } state, next_state;
199 
200 static __initdata char *victim;
201 static unsigned long byte_count __initdata;
202 static __initdata loff_t this_header, next_header;
203 
204 static inline void __init eat(unsigned n)
205 {
206         victim += n;
207         this_header += n;
208         byte_count -= n;
209 }
210 
211 static __initdata char *vcollected;
212 static __initdata char *collected;
213 static long remains __initdata;
214 static __initdata char *collect;
215 
216 static void __init read_into(char *buf, unsigned size, enum state next)
217 {
218         if (byte_count >= size) {
219                 collected = victim;
220                 eat(size);
221                 state = next;
222         } else {
223                 collect = collected = buf;
224                 remains = size;
225                 next_state = next;
226                 state = Collect;
227         }
228 }
229 
230 static __initdata char *header_buf, *symlink_buf, *name_buf;
231 
232 static int __init do_start(void)
233 {
234         read_into(header_buf, 110, GotHeader);
235         return 0;
236 }
237 
238 static int __init do_collect(void)
239 {
240         unsigned long n = remains;
241         if (byte_count < n)
242                 n = byte_count;
243         memcpy(collect, victim, n);
244         eat(n);
245         collect += n;
246         if ((remains -= n) != 0)
247                 return 1;
248         state = next_state;
249         return 0;
250 }
251 
252 static int __init do_header(void)
253 {
254         if (memcmp(collected, "070707", 6)==0) {
255                 error("incorrect cpio method used: use -H newc option");
256                 return 1;
257         }
258         if (memcmp(collected, "070701", 6)) {
259                 error("no cpio magic");
260                 return 1;
261         }
262         parse_header(collected);
263         next_header = this_header + N_ALIGN(name_len) + body_len;
264         next_header = (next_header + 3) & ~3;
265         state = SkipIt;
266         if (name_len <= 0 || name_len > PATH_MAX)
267                 return 0;
268         if (S_ISLNK(mode)) {
269                 if (body_len > PATH_MAX)
270                         return 0;
271                 collect = collected = symlink_buf;
272                 remains = N_ALIGN(name_len) + body_len;
273                 next_state = GotSymlink;
274                 state = Collect;
275                 return 0;
276         }
277         if (S_ISREG(mode) || !body_len)
278                 read_into(name_buf, N_ALIGN(name_len), GotName);
279         return 0;
280 }
281 
282 static int __init do_skip(void)
283 {
284         if (this_header + byte_count < next_header) {
285                 eat(byte_count);
286                 return 1;
287         } else {
288                 eat(next_header - this_header);
289                 state = next_state;
290                 return 0;
291         }
292 }
293 
294 static int __init do_reset(void)
295 {
296         while (byte_count && *victim == '\0')
297                 eat(1);
298         if (byte_count && (this_header & 3))
299                 error("broken padding");
300         return 1;
301 }
302 
303 static int __init maybe_link(void)
304 {
305         if (nlink >= 2) {
306                 char *old = find_link(major, minor, ino, mode, collected);
307                 if (old)
308                         return (sys_link(old, collected) < 0) ? -1 : 1;
309         }
310         return 0;
311 }
312 
313 static void __init clean_path(char *path, umode_t fmode)
314 {
315         struct stat st;
316 
317         if (!sys_newlstat(path, &st) && (st.st_mode ^ fmode) & S_IFMT) {
318                 if (S_ISDIR(st.st_mode))
319                         sys_rmdir(path);
320                 else
321                         sys_unlink(path);
322         }
323 }
324 
325 static __initdata int wfd;
326 
327 static int __init do_name(void)
328 {
329         state = SkipIt;
330         next_state = Reset;
331         if (strcmp(collected, "TRAILER!!!") == 0) {
332                 free_hash();
333                 return 0;
334         }
335         clean_path(collected, mode);
336         if (S_ISREG(mode)) {
337                 int ml = maybe_link();
338                 if (ml >= 0) {
339                         int openflags = O_WRONLY|O_CREAT;
340                         if (ml != 1)
341                                 openflags |= O_TRUNC;
342                         wfd = sys_open(collected, openflags, mode);
343 
344                         if (wfd >= 0) {
345                                 sys_fchown(wfd, uid, gid);
346                                 sys_fchmod(wfd, mode);
347                                 if (body_len)
348                                         sys_ftruncate(wfd, body_len);
349                                 vcollected = kstrdup(collected, GFP_KERNEL);
350                                 state = CopyFile;
351                         }
352                 }
353         } else if (S_ISDIR(mode)) {
354                 sys_mkdir(collected, mode);
355                 sys_chown(collected, uid, gid);
356                 sys_chmod(collected, mode);
357                 dir_add(collected, mtime);
358         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
359                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
360                 if (maybe_link() == 0) {
361                         sys_mknod(collected, mode, rdev);
362                         sys_chown(collected, uid, gid);
363                         sys_chmod(collected, mode);
364                         do_utime(collected, mtime);
365                 }
366         }
367         return 0;
368 }
369 
370 static int __init do_copy(void)
371 {
372         if (byte_count >= body_len) {
373                 if (xwrite(wfd, victim, body_len) != body_len)
374                         error("write error");
375                 sys_close(wfd);
376                 do_utime(vcollected, mtime);
377                 kfree(vcollected);
378                 eat(body_len);
379                 state = SkipIt;
380                 return 0;
381         } else {
382                 if (xwrite(wfd, victim, byte_count) != byte_count)
383                         error("write error");
384                 body_len -= byte_count;
385                 eat(byte_count);
386                 return 1;
387         }
388 }
389 
390 static int __init do_symlink(void)
391 {
392         collected[N_ALIGN(name_len) + body_len] = '\0';
393         clean_path(collected, 0);
394         sys_symlink(collected + N_ALIGN(name_len), collected);
395         sys_lchown(collected, uid, gid);
396         do_utime(collected, mtime);
397         state = SkipIt;
398         next_state = Reset;
399         return 0;
400 }
401 
402 static __initdata int (*actions[])(void) = {
403         [Start]         = do_start,
404         [Collect]       = do_collect,
405         [GotHeader]     = do_header,
406         [SkipIt]        = do_skip,
407         [GotName]       = do_name,
408         [CopyFile]      = do_copy,
409         [GotSymlink]    = do_symlink,
410         [Reset]         = do_reset,
411 };
412 
413 static long __init write_buffer(char *buf, unsigned long len)
414 {
415         byte_count = len;
416         victim = buf;
417 
418         while (!actions[state]())
419                 ;
420         return len - byte_count;
421 }
422 
423 static long __init flush_buffer(void *bufv, unsigned long len)
424 {
425         char *buf = (char *) bufv;
426         long written;
427         long origLen = len;
428         if (message)
429                 return -1;
430         while ((written = write_buffer(buf, len)) < len && !message) {
431                 char c = buf[written];
432                 if (c == '') {
433                         buf += written;
434                         len -= written;
435                         state = Start;
436                 } else if (c == 0) {
437                         buf += written;
438                         len -= written;
439                         state = Reset;
440                 } else
441                         error("junk in compressed archive");
442         }
443         return origLen;
444 }
445 
446 static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
447 
448 #include <linux/decompress/generic.h>
449 
450 static char * __init unpack_to_rootfs(char *buf, unsigned long len)
451 {
452         long written;
453         decompress_fn decompress;
454         const char *compress_name;
455         static __initdata char msg_buf[64];
456 
457         header_buf = kmalloc(110, GFP_KERNEL);
458         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
459         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
460 
461         if (!header_buf || !symlink_buf || !name_buf)
462                 panic("can't allocate buffers");
463 
464         state = Start;
465         this_header = 0;
466         message = NULL;
467         while (!message && len) {
468                 loff_t saved_offset = this_header;
469                 if (*buf == '' && !(this_header & 3)) {
470                         state = Start;
471                         written = write_buffer(buf, len);
472                         buf += written;
473                         len -= written;
474                         continue;
475                 }
476                 if (!*buf) {
477                         buf++;
478                         len--;
479                         this_header++;
480                         continue;
481                 }
482                 this_header = 0;
483                 decompress = decompress_method(buf, len, &compress_name);
484                 pr_debug("Detected %s compressed data\n", compress_name);
485                 if (decompress) {
486                         int res = decompress(buf, len, NULL, flush_buffer, NULL,
487                                    &my_inptr, error);
488                         if (res)
489                                 error("decompressor failed");
490                 } else if (compress_name) {
491                         if (!message) {
492                                 snprintf(msg_buf, sizeof msg_buf,
493                                          "compression method %s not configured",
494                                          compress_name);
495                                 message = msg_buf;
496                         }
497                 } else
498                         error("junk in compressed archive");
499                 if (state != Reset)
500                         error("junk in compressed archive");
501                 this_header = saved_offset + my_inptr;
502                 buf += my_inptr;
503                 len -= my_inptr;
504         }
505         dir_utime();
506         kfree(name_buf);
507         kfree(symlink_buf);
508         kfree(header_buf);
509         return message;
510 }
511 
512 static int __initdata do_retain_initrd;
513 
514 static int __init retain_initrd_param(char *str)
515 {
516         if (*str)
517                 return 0;
518         do_retain_initrd = 1;
519         return 1;
520 }
521 __setup("retain_initrd", retain_initrd_param);
522 
523 extern char __initramfs_start[];
524 extern unsigned long __initramfs_size;
525 #include <linux/initrd.h>
526 #include <linux/kexec.h>
527 
528 static void __init free_initrd(void)
529 {
530 #ifdef CONFIG_KEXEC_CORE
531         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
532         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
533 #endif
534         if (do_retain_initrd)
535                 goto skip;
536 
537 #ifdef CONFIG_KEXEC_CORE
538         /*
539          * If the initrd region is overlapped with crashkernel reserved region,
540          * free only memory that is not part of crashkernel region.
541          */
542         if (initrd_start < crashk_end && initrd_end > crashk_start) {
543                 /*
544                  * Initialize initrd memory region since the kexec boot does
545                  * not do.
546                  */
547                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
548                 if (initrd_start < crashk_start)
549                         free_initrd_mem(initrd_start, crashk_start);
550                 if (initrd_end > crashk_end)
551                         free_initrd_mem(crashk_end, initrd_end);
552         } else
553 #endif
554                 free_initrd_mem(initrd_start, initrd_end);
555 skip:
556         initrd_start = 0;
557         initrd_end = 0;
558 }
559 
560 #ifdef CONFIG_BLK_DEV_RAM
561 #define BUF_SIZE 1024
562 static void __init clean_rootfs(void)
563 {
564         int fd;
565         void *buf;
566         struct linux_dirent64 *dirp;
567         int num;
568 
569         fd = sys_open("/", O_RDONLY, 0);
570         WARN_ON(fd < 0);
571         if (fd < 0)
572                 return;
573         buf = kzalloc(BUF_SIZE, GFP_KERNEL);
574         WARN_ON(!buf);
575         if (!buf) {
576                 sys_close(fd);
577                 return;
578         }
579 
580         dirp = buf;
581         num = sys_getdents64(fd, dirp, BUF_SIZE);
582         while (num > 0) {
583                 while (num > 0) {
584                         struct stat st;
585                         int ret;
586 
587                         ret = sys_newlstat(dirp->d_name, &st);
588                         WARN_ON_ONCE(ret);
589                         if (!ret) {
590                                 if (S_ISDIR(st.st_mode))
591                                         sys_rmdir(dirp->d_name);
592                                 else
593                                         sys_unlink(dirp->d_name);
594                         }
595 
596                         num -= dirp->d_reclen;
597                         dirp = (void *)dirp + dirp->d_reclen;
598                 }
599                 dirp = buf;
600                 memset(buf, 0, BUF_SIZE);
601                 num = sys_getdents64(fd, dirp, BUF_SIZE);
602         }
603 
604         sys_close(fd);
605         kfree(buf);
606 }
607 #endif
608 
609 static int __init populate_rootfs(void)
610 {
611         /* Load the built in initramfs */
612         char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
613         if (err)
614                 panic("%s", err); /* Failed to decompress INTERNAL initramfs */
615         /* If available load the bootloader supplied initrd */
616         if (initrd_start) {
617 #ifdef CONFIG_BLK_DEV_RAM
618                 int fd;
619                 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
620                 err = unpack_to_rootfs((char *)initrd_start,
621                         initrd_end - initrd_start);
622                 if (!err) {
623                         free_initrd();
624                         goto done;
625                 } else {
626                         clean_rootfs();
627                         unpack_to_rootfs(__initramfs_start, __initramfs_size);
628                 }
629                 printk(KERN_INFO "rootfs image is not initramfs (%s)"
630                                 "; looks like an initrd\n", err);
631                 fd = sys_open("/initrd.image",
632                               O_WRONLY|O_CREAT, 0700);
633                 if (fd >= 0) {
634                         ssize_t written = xwrite(fd, (char *)initrd_start,
635                                                 initrd_end - initrd_start);
636 
637                         if (written != initrd_end - initrd_start)
638                                 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
639                                        written, initrd_end - initrd_start);
640 
641                         sys_close(fd);
642                         free_initrd();
643                 }
644         done:
645                 /* empty statement */;
646 #else
647                 printk(KERN_INFO "Unpacking initramfs...\n");
648                 err = unpack_to_rootfs((char *)initrd_start,
649                         initrd_end - initrd_start);
650                 if (err)
651                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
652                 free_initrd();
653 #endif
654         }
655         flush_delayed_fput();
656         /*
657          * Try loading default modules from initramfs.  This gives
658          * us a chance to load before device_initcalls.
659          */
660         load_default_modules();
661 
662         return 0;
663 }
664 rootfs_initcall(populate_rootfs);
665 

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