cb6ff20807
Support XIP on files unpacked from the initramfs image on NOMMU systems. This
simply requires the length of the file to be preset so that the ramfs fs can
attempt to garner sufficient contiguous storage to store the file (NOMMU mmap
can only map contiguous RAM).
All the other bits to do XIP on initramfs files are present:
(1) ramfs's truncate attempts to allocate a contiguous run of pages when a
file is truncated upwards from nothing.
(2) ramfs sets BDI on its files to indicate direct mapping is possible, and
that its files can be mapped for read, write and exec.
(3) NOMMU mmap() will use the above bits to determine that it can do XIP.
Possibly this needs better controls, because it will _always_ try and do
XIP.
One disadvantage of this very simplistic approach is that sufficient space
will be allocated to store the whole file, and not just the bit that would be
XIP'd. To deal with this, though, the initramfs unpacker would have to be
able to parse the file contents.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
617 lines
13 KiB
C
617 lines
13 KiB
C
#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/fcntl.h>
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#include <linux/delay.h>
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#include <linux/string.h>
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#include <linux/syscalls.h>
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#include <linux/utime.h>
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static __initdata char *message;
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static void __init error(char *x)
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{
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if (!message)
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message = x;
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}
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/* link hash */
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#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
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static __initdata struct hash {
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int ino, minor, major;
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mode_t mode;
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struct hash *next;
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char name[N_ALIGN(PATH_MAX)];
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} *head[32];
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static inline int hash(int major, int minor, int ino)
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{
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unsigned long tmp = ino + minor + (major << 3);
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tmp += tmp >> 5;
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return tmp & 31;
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}
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static char __init *find_link(int major, int minor, int ino,
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mode_t mode, char *name)
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{
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struct hash **p, *q;
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for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
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if ((*p)->ino != ino)
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continue;
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if ((*p)->minor != minor)
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continue;
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if ((*p)->major != major)
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continue;
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if (((*p)->mode ^ mode) & S_IFMT)
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continue;
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return (*p)->name;
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}
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q = kmalloc(sizeof(struct hash), GFP_KERNEL);
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if (!q)
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panic("can't allocate link hash entry");
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q->major = major;
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q->minor = minor;
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q->ino = ino;
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q->mode = mode;
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strcpy(q->name, name);
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q->next = NULL;
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*p = q;
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return NULL;
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}
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static void __init free_hash(void)
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{
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struct hash **p, *q;
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for (p = head; p < head + 32; p++) {
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while (*p) {
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q = *p;
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*p = q->next;
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kfree(q);
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}
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}
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}
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static long __init do_utime(char __user *filename, time_t mtime)
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{
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struct timespec t[2];
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t[0].tv_sec = mtime;
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t[0].tv_nsec = 0;
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t[1].tv_sec = mtime;
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t[1].tv_nsec = 0;
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return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
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}
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static __initdata LIST_HEAD(dir_list);
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struct dir_entry {
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struct list_head list;
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char *name;
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time_t mtime;
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};
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static void __init dir_add(const char *name, time_t mtime)
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{
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struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
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if (!de)
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panic("can't allocate dir_entry buffer");
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INIT_LIST_HEAD(&de->list);
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de->name = kstrdup(name, GFP_KERNEL);
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de->mtime = mtime;
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list_add(&de->list, &dir_list);
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}
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static void __init dir_utime(void)
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{
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struct dir_entry *de, *tmp;
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list_for_each_entry_safe(de, tmp, &dir_list, list) {
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list_del(&de->list);
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do_utime(de->name, de->mtime);
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kfree(de->name);
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kfree(de);
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}
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}
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static __initdata time_t mtime;
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/* cpio header parsing */
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static __initdata unsigned long ino, major, minor, nlink;
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static __initdata mode_t mode;
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static __initdata unsigned long body_len, name_len;
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static __initdata uid_t uid;
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static __initdata gid_t gid;
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static __initdata unsigned rdev;
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static void __init parse_header(char *s)
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{
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unsigned long parsed[12];
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char buf[9];
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int i;
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buf[8] = '\0';
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for (i = 0, s += 6; i < 12; i++, s += 8) {
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memcpy(buf, s, 8);
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parsed[i] = simple_strtoul(buf, NULL, 16);
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}
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ino = parsed[0];
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mode = parsed[1];
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uid = parsed[2];
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gid = parsed[3];
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nlink = parsed[4];
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mtime = parsed[5];
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body_len = parsed[6];
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major = parsed[7];
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minor = parsed[8];
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rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
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name_len = parsed[11];
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}
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/* FSM */
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static __initdata enum state {
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Start,
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Collect,
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GotHeader,
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SkipIt,
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GotName,
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CopyFile,
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GotSymlink,
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Reset
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} state, next_state;
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static __initdata char *victim;
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static __initdata unsigned count;
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static __initdata loff_t this_header, next_header;
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static __initdata int dry_run;
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static inline void __init eat(unsigned n)
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{
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victim += n;
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this_header += n;
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count -= n;
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}
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static __initdata char *vcollected;
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static __initdata char *collected;
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static __initdata int remains;
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static __initdata char *collect;
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static void __init read_into(char *buf, unsigned size, enum state next)
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{
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if (count >= size) {
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collected = victim;
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eat(size);
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state = next;
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} else {
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collect = collected = buf;
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remains = size;
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next_state = next;
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state = Collect;
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}
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}
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static __initdata char *header_buf, *symlink_buf, *name_buf;
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static int __init do_start(void)
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{
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read_into(header_buf, 110, GotHeader);
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return 0;
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}
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static int __init do_collect(void)
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{
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unsigned n = remains;
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if (count < n)
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n = count;
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memcpy(collect, victim, n);
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eat(n);
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collect += n;
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if ((remains -= n) != 0)
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return 1;
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state = next_state;
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return 0;
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}
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static int __init do_header(void)
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{
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if (memcmp(collected, "070707", 6)==0) {
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error("incorrect cpio method used: use -H newc option");
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return 1;
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}
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if (memcmp(collected, "070701", 6)) {
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error("no cpio magic");
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return 1;
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}
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parse_header(collected);
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next_header = this_header + N_ALIGN(name_len) + body_len;
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next_header = (next_header + 3) & ~3;
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if (dry_run) {
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read_into(name_buf, N_ALIGN(name_len), GotName);
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return 0;
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}
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state = SkipIt;
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if (name_len <= 0 || name_len > PATH_MAX)
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return 0;
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if (S_ISLNK(mode)) {
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if (body_len > PATH_MAX)
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return 0;
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collect = collected = symlink_buf;
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remains = N_ALIGN(name_len) + body_len;
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next_state = GotSymlink;
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state = Collect;
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return 0;
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}
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if (S_ISREG(mode) || !body_len)
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read_into(name_buf, N_ALIGN(name_len), GotName);
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return 0;
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}
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static int __init do_skip(void)
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{
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if (this_header + count < next_header) {
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eat(count);
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return 1;
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} else {
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eat(next_header - this_header);
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state = next_state;
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return 0;
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}
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}
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static int __init do_reset(void)
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{
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while(count && *victim == '\0')
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eat(1);
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if (count && (this_header & 3))
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error("broken padding");
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return 1;
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}
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static int __init maybe_link(void)
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{
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if (nlink >= 2) {
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char *old = find_link(major, minor, ino, mode, collected);
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if (old)
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return (sys_link(old, collected) < 0) ? -1 : 1;
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}
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return 0;
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}
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static void __init clean_path(char *path, mode_t mode)
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{
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struct stat st;
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if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
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if (S_ISDIR(st.st_mode))
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sys_rmdir(path);
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else
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sys_unlink(path);
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}
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}
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static __initdata int wfd;
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static int __init do_name(void)
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{
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state = SkipIt;
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next_state = Reset;
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if (strcmp(collected, "TRAILER!!!") == 0) {
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free_hash();
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return 0;
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}
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if (dry_run)
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return 0;
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clean_path(collected, mode);
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if (S_ISREG(mode)) {
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int ml = maybe_link();
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if (ml >= 0) {
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int openflags = O_WRONLY|O_CREAT;
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if (ml != 1)
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openflags |= O_TRUNC;
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wfd = sys_open(collected, openflags, mode);
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if (wfd >= 0) {
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sys_fchown(wfd, uid, gid);
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sys_fchmod(wfd, mode);
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sys_ftruncate(wfd, body_len);
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vcollected = kstrdup(collected, GFP_KERNEL);
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state = CopyFile;
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}
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}
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} else if (S_ISDIR(mode)) {
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sys_mkdir(collected, mode);
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sys_chown(collected, uid, gid);
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sys_chmod(collected, mode);
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dir_add(collected, mtime);
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} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
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S_ISFIFO(mode) || S_ISSOCK(mode)) {
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if (maybe_link() == 0) {
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sys_mknod(collected, mode, rdev);
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sys_chown(collected, uid, gid);
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sys_chmod(collected, mode);
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do_utime(collected, mtime);
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}
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}
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return 0;
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}
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static int __init do_copy(void)
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{
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if (count >= body_len) {
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sys_write(wfd, victim, body_len);
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sys_close(wfd);
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do_utime(vcollected, mtime);
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kfree(vcollected);
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eat(body_len);
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state = SkipIt;
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return 0;
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} else {
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sys_write(wfd, victim, count);
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body_len -= count;
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eat(count);
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return 1;
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}
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}
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static int __init do_symlink(void)
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{
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collected[N_ALIGN(name_len) + body_len] = '\0';
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clean_path(collected, 0);
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sys_symlink(collected + N_ALIGN(name_len), collected);
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sys_lchown(collected, uid, gid);
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do_utime(collected, mtime);
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state = SkipIt;
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next_state = Reset;
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return 0;
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}
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static __initdata int (*actions[])(void) = {
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[Start] = do_start,
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[Collect] = do_collect,
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[GotHeader] = do_header,
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[SkipIt] = do_skip,
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[GotName] = do_name,
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[CopyFile] = do_copy,
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[GotSymlink] = do_symlink,
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[Reset] = do_reset,
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};
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static int __init write_buffer(char *buf, unsigned len)
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{
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count = len;
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victim = buf;
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while (!actions[state]())
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;
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return len - count;
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}
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static void __init flush_buffer(char *buf, unsigned len)
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{
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int written;
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if (message)
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return;
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while ((written = write_buffer(buf, len)) < len && !message) {
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char c = buf[written];
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if (c == '0') {
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buf += written;
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len -= written;
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state = Start;
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} else if (c == 0) {
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buf += written;
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len -= written;
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state = Reset;
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} else
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error("junk in compressed archive");
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}
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}
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/*
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* gzip declarations
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*/
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#define OF(args) args
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#ifndef memzero
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#define memzero(s, n) memset ((s), 0, (n))
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#endif
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typedef unsigned char uch;
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typedef unsigned short ush;
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typedef unsigned long ulg;
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#define WSIZE 0x8000 /* window size--must be a power of two, and */
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/* at least 32K for zip's deflate method */
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static uch *inbuf;
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static uch *window;
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static unsigned insize; /* valid bytes in inbuf */
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static unsigned inptr; /* index of next byte to be processed in inbuf */
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static unsigned outcnt; /* bytes in output buffer */
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static long bytes_out;
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#define get_byte() (inptr < insize ? inbuf[inptr++] : -1)
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/* Diagnostic functions (stubbed out) */
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#define Assert(cond,msg)
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#define Trace(x)
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#define Tracev(x)
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#define Tracevv(x)
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#define Tracec(c,x)
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#define Tracecv(c,x)
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#define STATIC static
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#define INIT __init
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static void __init flush_window(void);
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static void __init error(char *m);
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#define NO_INFLATE_MALLOC
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#include "../lib/inflate.c"
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/* ===========================================================================
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* Write the output window window[0..outcnt-1] and update crc and bytes_out.
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* (Used for the decompressed data only.)
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*/
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static void __init flush_window(void)
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{
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ulg c = crc; /* temporary variable */
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unsigned n;
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uch *in, ch;
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flush_buffer(window, outcnt);
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in = window;
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for (n = 0; n < outcnt; n++) {
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ch = *in++;
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c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
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}
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crc = c;
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bytes_out += (ulg)outcnt;
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outcnt = 0;
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}
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static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
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{
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int written;
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dry_run = check_only;
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header_buf = kmalloc(110, GFP_KERNEL);
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symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
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name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
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window = kmalloc(WSIZE, GFP_KERNEL);
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if (!window || !header_buf || !symlink_buf || !name_buf)
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panic("can't allocate buffers");
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state = Start;
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this_header = 0;
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message = NULL;
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while (!message && len) {
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loff_t saved_offset = this_header;
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if (*buf == '0' && !(this_header & 3)) {
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state = Start;
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written = write_buffer(buf, len);
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buf += written;
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len -= written;
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continue;
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}
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if (!*buf) {
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buf++;
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len--;
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this_header++;
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continue;
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}
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this_header = 0;
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insize = len;
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inbuf = buf;
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inptr = 0;
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outcnt = 0; /* bytes in output buffer */
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bytes_out = 0;
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crc = (ulg)0xffffffffL; /* shift register contents */
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makecrc();
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gunzip();
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if (state != Reset)
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error("junk in gzipped archive");
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this_header = saved_offset + inptr;
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buf += inptr;
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len -= inptr;
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}
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dir_utime();
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kfree(window);
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kfree(name_buf);
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kfree(symlink_buf);
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kfree(header_buf);
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return message;
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}
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static int __initdata do_retain_initrd;
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static int __init retain_initrd_param(char *str)
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{
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if (*str)
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return 0;
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do_retain_initrd = 1;
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return 1;
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}
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__setup("retain_initrd", retain_initrd_param);
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extern char __initramfs_start[], __initramfs_end[];
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#include <linux/initrd.h>
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#include <linux/kexec.h>
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static void __init free_initrd(void)
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{
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|
#ifdef CONFIG_KEXEC
|
|
unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
|
|
unsigned long crashk_end = (unsigned long)__va(crashk_res.end);
|
|
#endif
|
|
if (do_retain_initrd)
|
|
goto skip;
|
|
|
|
#ifdef CONFIG_KEXEC
|
|
/*
|
|
* If the initrd region is overlapped with crashkernel reserved region,
|
|
* free only memory that is not part of crashkernel region.
|
|
*/
|
|
if (initrd_start < crashk_end && initrd_end > crashk_start) {
|
|
/*
|
|
* Initialize initrd memory region since the kexec boot does
|
|
* not do.
|
|
*/
|
|
memset((void *)initrd_start, 0, initrd_end - initrd_start);
|
|
if (initrd_start < crashk_start)
|
|
free_initrd_mem(initrd_start, crashk_start);
|
|
if (initrd_end > crashk_end)
|
|
free_initrd_mem(crashk_end, initrd_end);
|
|
} else
|
|
#endif
|
|
free_initrd_mem(initrd_start, initrd_end);
|
|
skip:
|
|
initrd_start = 0;
|
|
initrd_end = 0;
|
|
}
|
|
|
|
static int __init populate_rootfs(void)
|
|
{
|
|
char *err = unpack_to_rootfs(__initramfs_start,
|
|
__initramfs_end - __initramfs_start, 0);
|
|
if (err)
|
|
panic(err);
|
|
if (initrd_start) {
|
|
#ifdef CONFIG_BLK_DEV_RAM
|
|
int fd;
|
|
printk(KERN_INFO "checking if image is initramfs...");
|
|
err = unpack_to_rootfs((char *)initrd_start,
|
|
initrd_end - initrd_start, 1);
|
|
if (!err) {
|
|
printk(" it is\n");
|
|
unpack_to_rootfs((char *)initrd_start,
|
|
initrd_end - initrd_start, 0);
|
|
free_initrd();
|
|
return 0;
|
|
}
|
|
printk("it isn't (%s); looks like an initrd\n", err);
|
|
fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700);
|
|
if (fd >= 0) {
|
|
sys_write(fd, (char *)initrd_start,
|
|
initrd_end - initrd_start);
|
|
sys_close(fd);
|
|
free_initrd();
|
|
}
|
|
#else
|
|
printk(KERN_INFO "Unpacking initramfs...");
|
|
err = unpack_to_rootfs((char *)initrd_start,
|
|
initrd_end - initrd_start, 0);
|
|
if (err)
|
|
panic(err);
|
|
printk(" done\n");
|
|
free_initrd();
|
|
#endif
|
|
}
|
|
return 0;
|
|
}
|
|
rootfs_initcall(populate_rootfs);
|