linux/init/initramfs.c at master · fabgithub/linux · GitHub

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* Many of the syscalls used in this file expect some of the arguments

* to be __user pointers not __kernel pointers. To limit the sparse

* noise, turn off sparse checking for this file.

#ifdef __CHECKER__

#undef __CHECKER__

#warning "Sparse checking disabled for this file"

#endif

#include <linux/init.h>

#include <linux/fs.h>

#include <linux/slab.h>

#include <linux/types.h>

#include <linux/fcntl.h>

#include <linux/delay.h>

#include <linux/string.h>

#include <linux/dirent.h>

#include <linux/syscalls.h>

#include <linux/utime.h>

static __initdata char *message;

static void __init error(char *x)

{

if (!message)

message = x;

}

/* link hash */

#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)

static __initdata struct hash {

int ino, minor, major;

umode_t mode;

struct hash *next;

char name[N_ALIGN(PATH_MAX)];

} *head[32];

static inline int hash(int major, int minor, int ino)

{

unsigned long tmp = ino + minor + (major << 3);

tmp += tmp >> 5;

return tmp & 31;

}

static char __init *find_link(int major, int minor, int ino,

umode_t mode, char *name)

{

struct hash **p, *q;

for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {

if ((*p)->ino != ino)

continue;

if ((*p)->minor != minor)

continue;

if ((*p)->major != major)

continue;

if (((*p)->mode ^ mode) & S_IFMT)

continue;

return (*p)->name;

}

q = kmalloc(sizeof(struct hash), GFP_KERNEL);

if (!q)

panic("can't allocate link hash entry");

q->major = major;

q->minor = minor;

q->ino = ino;

q->mode = mode;

strcpy(q->name, name);

q->next = NULL;

*p = q;

return NULL;

}

static void __init free_hash(void)

{

struct hash **p, *q;

for (p = head; p < head + 32; p++) {

while (*p) {

q = *p;

*p = q->next;

kfree(q);

}

static long __init do_utime(char *filename, time_t mtime)

{

struct timespec t[2];

t[0].tv_sec = mtime;

t[0].tv_nsec = 0;

t[1].tv_sec = mtime;

t[1].tv_nsec = 0;

return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);

}

static __initdata LIST_HEAD(dir_list);

struct dir_entry {

struct list_head list;

char *name;

time_t mtime;

};

static void __init dir_add(const char *name, time_t mtime)

{

struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);

if (!de)

panic("can't allocate dir_entry buffer");

INIT_LIST_HEAD(&de->list);

de->name = kstrdup(name, GFP_KERNEL);

de->mtime = mtime;

list_add(&de->list, &dir_list);

}

static void __init dir_utime(void)

{

struct dir_entry *de, *tmp;

list_for_each_entry_safe(de, tmp, &dir_list, list) {

list_del(&de->list);

do_utime(de->name, de->mtime);

kfree(de->name);

kfree(de);

}

static __initdata time_t mtime;

/* cpio header parsing */

static __initdata unsigned long ino, major, minor, nlink;

static __initdata umode_t mode;

static __initdata unsigned long body_len, name_len;

static __initdata uid_t uid;

static __initdata gid_t gid;

static __initdata unsigned rdev;

static void __init parse_header(char *s)

{

unsigned long parsed[12];

char buf[9];

int i;

buf[8] = '\0';

for (i = 0, s += 6; i < 12; i++, s += 8) {

memcpy(buf, s, 8);

parsed[i] = simple_strtoul(buf, NULL, 16);

}

ino = parsed[0];

mode = parsed[1];

uid = parsed[2];

gid = parsed[3];

nlink = parsed[4];

mtime = parsed[5];

body_len = parsed[6];

major = parsed[7];

minor = parsed[8];

rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));

name_len = parsed[11];

}

/* FSM */

static __initdata enum state {

Start,

Collect,

GotHeader,

SkipIt,

GotName,

CopyFile,

GotSymlink,

Reset

} state, next_state;

static __initdata char *victim;

static __initdata unsigned count;

static __initdata loff_t this_header, next_header;

static inline void __init eat(unsigned n)

{

victim += n;

this_header += n;

count -= n;

}

static __initdata char *vcollected;

static __initdata char *collected;

static __initdata int remains;

static __initdata char *collect;

static void __init read_into(char *buf, unsigned size, enum state next)

{

if (count >= size) {

collected = victim;

eat(size);

state = next;

} else {

collect = collected = buf;

remains = size;

next_state = next;

state = Collect;

}

static __initdata char *header_buf, *symlink_buf, *name_buf;

static int __init do_start(void)

{

read_into(header_buf, 110, GotHeader);

return 0;

}

static int __init do_collect(void)

{

unsigned n = remains;

if (count < n)

n = count;

memcpy(collect, victim, n);

eat(n);

collect += n;

if ((remains -= n) != 0)

return 1;

state = next_state;

return 0;

}

static int __init do_header(void)

{

if (memcmp(collected, "070707", 6)==0) {

error("incorrect cpio method used: use -H newc option");

return 1;

}

if (memcmp(collected, "070701", 6)) {

error("no cpio magic");

return 1;

}

parse_header(collected);

next_header = this_header + N_ALIGN(name_len) + body_len;

next_header = (next_header + 3) & ~3;

state = SkipIt;

if (name_len <= 0 || name_len > PATH_MAX)

return 0;

if (S_ISLNK(mode)) {

if (body_len > PATH_MAX)

return 0;

collect = collected = symlink_buf;

remains = N_ALIGN(name_len) + body_len;

next_state = GotSymlink;

state = Collect;

return 0;

}

if (S_ISREG(mode) || !body_len)

read_into(name_buf, N_ALIGN(name_len), GotName);

return 0;

}

static int __init do_skip(void)

{

if (this_header + count < next_header) {

eat(count);

return 1;

} else {

eat(next_header - this_header);

state = next_state;

return 0;

}

static int __init do_reset(void)

{

while(count && *victim == '\0')

eat(1);

if (count && (this_header & 3))

error("broken padding");

return 1;

}

static int __init maybe_link(void)

{

if (nlink >= 2) {

char *old = find_link(major, minor, ino, mode, collected);

if (old)

return (sys_link(old, collected) < 0) ? -1 : 1;

}

return 0;

}

static void __init clean_path(char *path, umode_t mode)

{

struct stat st;

if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {

if (S_ISDIR(st.st_mode))

sys_rmdir(path);

else

sys_unlink(path);

}

static __initdata int wfd;

static int __init do_name(void)

{

state = SkipIt;

next_state = Reset;

if (strcmp(collected, "TRAILER!!!") == 0) {

free_hash();

return 0;

}

clean_path(collected, mode);

if (S_ISREG(mode)) {

int ml = maybe_link();

if (ml >= 0) {

int openflags = O_WRONLY|O_CREAT;

if (ml != 1)

openflags |= O_TRUNC;

wfd = sys_open(collected, openflags, mode);

if (wfd >= 0) {

sys_fchown(wfd, uid, gid);

sys_fchmod(wfd, mode);

if (body_len)

sys_ftruncate(wfd, body_len);

vcollected = kstrdup(collected, GFP_KERNEL);

state = CopyFile;

}

} else if (S_ISDIR(mode)) {

sys_mkdir(collected, mode);

sys_chown(collected, uid, gid);

sys_chmod(collected, mode);

dir_add(collected, mtime);

} else if (S_ISBLK(mode) || S_ISCHR(mode) ||

S_ISFIFO(mode) || S_ISSOCK(mode)) {

if (maybe_link() == 0) {

sys_mknod(collected, mode, rdev);

sys_chown(collected, uid, gid);

sys_chmod(collected, mode);

do_utime(collected, mtime);

}

return 0;

}

static int __init do_copy(void)

{

if (count >= body_len) {

sys_write(wfd, victim, body_len);

sys_close(wfd);

do_utime(vcollected, mtime);

kfree(vcollected);

eat(body_len);

state = SkipIt;

return 0;

} else {

sys_write(wfd, victim, count);

body_len -= count;

eat(count);

return 1;

}

static int __init do_symlink(void)

{

collected[N_ALIGN(name_len) + body_len] = '\0';

clean_path(collected, 0);

sys_symlink(collected + N_ALIGN(name_len), collected);

sys_lchown(collected, uid, gid);

do_utime(collected, mtime);

state = SkipIt;

next_state = Reset;

return 0;

}

static __initdata int (*actions[])(void) = {

[Start] = do_start,

[Collect] = do_collect,

[GotHeader] = do_header,

[SkipIt] = do_skip,

[GotName] = do_name,

[CopyFile] = do_copy,

[GotSymlink] = do_symlink,

[Reset] = do_reset,

};

static int __init write_buffer(char *buf, unsigned len)

{

count = len;

victim = buf;

while (!actions[state]())

;

return len - count;

}

static int __init flush_buffer(void *bufv, unsigned len)

{

char *buf = (char *) bufv;

int written;

int origLen = len;

if (message)

return -1;

while ((written = write_buffer(buf, len)) < len && !message) {

char c = buf[written];

if (c == '0') {

buf += written;

len -= written;

state = Start;

} else if (c == 0) {

buf += written;

len -= written;

state = Reset;

} else

error("junk in compressed archive");

}

return origLen;

}

static unsigned my_inptr; /* index of next byte to be processed in inbuf */

#include <linux/decompress/generic.h>

static char * __init unpack_to_rootfs(char *buf, unsigned len)

{

int written, res;

decompress_fn decompress;

const char *compress_name;

static __initdata char msg_buf[64];

header_buf = kmalloc(110, GFP_KERNEL);

symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);

name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);

if (!header_buf || !symlink_buf || !name_buf)

panic("can't allocate buffers");

state = Start;

this_header = 0;

message = NULL;

while (!message && len) {

loff_t saved_offset = this_header;

if (*buf == '0' && !(this_header & 3)) {

state = Start;

written = write_buffer(buf, len);

buf += written;

len -= written;

continue;

}

if (!*buf) {

buf++;

len--;

this_header++;

continue;

}

this_header = 0;

decompress = decompress_method(buf, len, &compress_name);

if (decompress) {

res = decompress(buf, len, NULL, flush_buffer, NULL,

&my_inptr, error);

if (res)

error("decompressor failed");

} else if (compress_name) {

if (!message) {

snprintf(msg_buf, sizeof msg_buf,

"compression method %s not configured",

compress_name);

message = msg_buf;

}

} else

error("junk in compressed archive");

if (state != Reset)

error("junk in compressed archive");

this_header = saved_offset + my_inptr;

buf += my_inptr;

len -= my_inptr;

}

dir_utime();

kfree(name_buf);

kfree(symlink_buf);

kfree(header_buf);

return message;

}

static int __initdata do_retain_initrd;

static int __init retain_initrd_param(char *str)

{

if (*str)

return 0;

do_retain_initrd = 1;

return 1;

}

__setup("retain_initrd", retain_initrd_param);

extern char __initramfs_start[];

extern unsigned long __initramfs_size;

#include <linux/initrd.h>

#include <linux/kexec.h>

static void __init free_initrd(void)

{

#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;

}

#ifdef CONFIG_BLK_DEV_RAM

#define BUF_SIZE 1024

static void __init clean_rootfs(void)

{

int fd;

void *buf;

struct linux_dirent64 *dirp;

int num;

fd = sys_open("/", O_RDONLY, 0);

WARN_ON(fd < 0);

if (fd < 0)

return;

buf = kzalloc(BUF_SIZE, GFP_KERNEL);

WARN_ON(!buf);

if (!buf) {

sys_close(fd);

return;

}

dirp = buf;

num = sys_getdents64(fd, dirp, BUF_SIZE);

while (num > 0) {

struct stat st;

int ret;

ret = sys_newlstat(dirp->d_name, &st);

WARN_ON_ONCE(ret);

if (!ret) {

if (S_ISDIR(st.st_mode))

sys_rmdir(dirp->d_name);

else

sys_unlink(dirp->d_name);

}

num -= dirp->d_reclen;

dirp = (void *)dirp + dirp->d_reclen;

}

dirp = buf;

memset(buf, 0, BUF_SIZE);

num = sys_getdents64(fd, dirp, BUF_SIZE);

}

sys_close(fd);

kfree(buf);

}

#endif

static int __init populate_rootfs(void)

{

char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);

if (err)

panic(err); /* Failed to decompress INTERNAL initramfs */

if (initrd_start) {

#ifdef CONFIG_BLK_DEV_RAM

int fd;

printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");

err = unpack_to_rootfs((char *)initrd_start,

initrd_end - initrd_start);

if (!err) {

free_initrd();

goto done;

} else {

clean_rootfs();

unpack_to_rootfs(__initramfs_start, __initramfs_size);

}

printk(KERN_INFO "rootfs image is not initramfs (%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();

}

done:

#else

printk(KERN_INFO "Unpacking initramfs...\n");

err = unpack_to_rootfs((char *)initrd_start,

initrd_end - initrd_start);

if (err)

printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);

free_initrd();

#endif

* Try loading default modules from initramfs. This gives

* us a chance to load before device_initcalls.

load_default_modules();

}

return 0;

}

rootfs_initcall(populate_rootfs);

linux/init/initramfs.c at master · fabgithub/linux · GitHub

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