Commit a06650df authored by Jeff Garzik's avatar Jeff Garzik

Minimal initramfs support (based on Al Viro's work).

parent 2b738648
......@@ -209,7 +209,7 @@ init-y := init/
drivers-y := drivers/ sound/
net-y := net/
libs-y := lib/
core-y :=
core-y := usr/
SUBDIRS :=
ifeq ($(filter $(noconfig_targets),$(MAKECMDGOALS)),)
......
......@@ -18,6 +18,7 @@
LDFLAGS := -m elf_i386
OBJCOPYFLAGS := -O binary -R .note -R .comment -S
ARCHBLOBLFLAGS := -I binary -O elf32-i386 -B i386
LDFLAGS_vmlinux := -e stext
CFLAGS += -pipe
......
......@@ -77,6 +77,10 @@ SECTIONS
*(.initcall7.init)
}
__initcall_end = .;
. = ALIGN(4096);
__initramfs_start = .;
.init.ramfs : { *(.init.initramfs) }
__initramfs_end = .;
. = ALIGN(32);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
......
......@@ -2,7 +2,7 @@
# Makefile for the linux kernel.
#
obj-y := main.o version.o do_mounts.o
obj-y := main.o version.o do_mounts.o initramfs.o
# files to be removed upon make clean
clean-files := ../include/linux/compile.h
......
......@@ -748,9 +748,7 @@ void prepare_namespace(void)
mount_initrd = 0;
real_root_dev = ROOT_DEV;
#endif
sys_mkdir("/dev", 0700);
sys_mkdir("/root", 0700);
sys_mknod("/dev/console", S_IFCHR|0600, MKDEV(TTYAUX_MAJOR, 1));
#ifdef CONFIG_DEVFS_FS
sys_mount("devfs", "/dev", "devfs", 0, NULL);
do_devfs = 1;
......
#define __KERNEL_SYSCALLS__
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/unistd.h>
#include <linux/delay.h>
static void __init error(char *x)
{
panic("populate_root: %s\n", x);
}
static void __init *malloc(int size)
{
return kmalloc(size, GFP_KERNEL);
}
static void __init free(void *where)
{
kfree(where);
}
asmlinkage long sys_mkdir(char *name, int mode);
asmlinkage long sys_mknod(char *name, int mode, dev_t dev);
asmlinkage long sys_symlink(char *old, char *new);
asmlinkage long sys_link(char *old, char *new);
asmlinkage long sys_write(int fd, void *buf, ssize_t size);
asmlinkage long sys_chown(char *name, uid_t uid, gid_t gid);
asmlinkage long sys_lchown(char *name, uid_t uid, gid_t gid);
asmlinkage long sys_fchown(int fd, uid_t uid, gid_t gid);
asmlinkage long sys_chmod(char *name, mode_t mode);
asmlinkage long sys_fchmod(int fd, mode_t mode);
/* link hash */
static struct hash {
int ino, minor, major;
struct hash *next;
char *name;
} *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, 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;
return (*p)->name;
}
q = (struct hash *)malloc(sizeof(struct hash));
if (!q)
error("can't allocate link hash entry");
q->ino = ino;
q->minor = minor;
q->major = major;
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;
free(q);
}
}
}
/* cpio header parsing */
static __initdata unsigned long ino, major, minor, nlink;
static __initdata mode_t mode;
static __initdata unsigned long body_len, name_len;
static __initdata uid_t uid;
static __initdata gid_t gid;
static __initdata dev_t 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];
body_len = parsed[6];
major = parsed[7];
minor = parsed[8];
rdev = MKDEV(parsed[9], parsed[10]);
name_len = parsed[11];
}
/* FSM */
enum state {
Start,
Collect,
GotHeader,
SkipIt,
GotName,
CopyFile,
GotSymlink,
Reset
} state, next_state;
char *victim;
unsigned count;
loff_t this_header, next_header;
static inline void eat(unsigned n)
{
victim += n;
this_header += n;
count -= n;
}
#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
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)
return 1;
state = next_state;
return 0;
}
static int __init do_header(void)
{
parse_header(collected);
next_header = this_header + N_ALIGN(name_len) + body_len;
next_header = (next_header + 3) & ~3;
if (name_len <= 0 || name_len > PATH_MAX)
state = SkipIt;
else if (S_ISLNK(mode)) {
if (body_len > PATH_MAX)
state = SkipIt;
else {
collect = collected = symlink_buf;
remains = N_ALIGN(name_len) + body_len;
next_state = GotSymlink;
state = Collect;
}
} else if (body_len && !S_ISREG(mode))
state = SkipIt;
else
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, collected);
if (old)
return (sys_link(old, collected) < 0) ? -1 : 1;
}
return 0;
}
static __initdata int wfd;
static int __init do_name(void)
{
state = SkipIt;
next_state = Start;
if (strcmp(collected, "TRAILER!!!") == 0) {
free_hash();
next_state = Reset;
return 0;
}
printk(KERN_INFO "-> %s\n", collected);
if (S_ISREG(mode)) {
if (maybe_link() >= 0) {
wfd = sys_open(collected, O_WRONLY|O_CREAT, mode);
if (wfd >= 0) {
sys_fchown(wfd, uid, gid);
sys_fchmod(wfd, mode);
state = CopyFile;
}
}
} else if (S_ISDIR(mode)) {
sys_mkdir(collected, mode);
sys_chown(collected, uid, gid);
} 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);
}
} else
panic("populate_root: bogus mode: %o\n", mode);
return 0;
}
static int __init do_copy(void)
{
if (count >= body_len) {
sys_write(wfd, victim, body_len);
sys_close(wfd);
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';
sys_symlink(collected + N_ALIGN(name_len), collected);
sys_lchown(collected, uid, gid);
state = SkipIt;
next_state = Start;
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 void __init flush_buffer(char *buf, unsigned len)
{
int written;
while ((written = write_buffer(buf, len)) < len) {
char c = buf[written];
if (c == '0') {
buf += written;
len -= written;
state = Start;
continue;
} else
error("junk in compressed archive");
}
}
/*
* gzip declarations
*/
#define OF(args) args
#ifndef memzero
#define memzero(s, n) memset ((s), 0, (n))
#endif
typedef unsigned char uch;
typedef unsigned short ush;
typedef unsigned long ulg;
#define WSIZE 0x8000 /* window size--must be a power of two, and */
/* at least 32K for zip's deflate method */
static uch *inbuf;
static uch *window;
static unsigned insize; /* valid bytes in inbuf */
static unsigned inptr; /* index of next byte to be processed in inbuf */
static unsigned outcnt; /* bytes in output buffer */
static long bytes_out;
#define get_byte() (inptr < insize ? inbuf[inptr++] : -1)
/* Diagnostic functions (stubbed out) */
#define Assert(cond,msg)
#define Trace(x)
#define Tracev(x)
#define Tracevv(x)
#define Tracec(c,x)
#define Tracecv(c,x)
#define STATIC static
static void flush_window(void);
static void error(char *m);
static void gzip_mark(void **);
static void gzip_release(void **);
#include "../lib/inflate.c"
static void __init gzip_mark(void **ptr)
{
}
static void __init gzip_release(void **ptr)
{
}
/* ===========================================================================
* Write the output window window[0..outcnt-1] and update crc and bytes_out.
* (Used for the decompressed data only.)
*/
static void __init flush_window(void)
{
ulg c = crc; /* temporary variable */
unsigned n;
uch *in, ch;
flush_buffer(window, outcnt);
in = window;
for (n = 0; n < outcnt; n++) {
ch = *in++;
c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
}
crc = c;
bytes_out += (ulg)outcnt;
outcnt = 0;
}
static void __init unpack_to_rootfs(char *buf, unsigned len)
{
int written;
header_buf = malloc(110);
symlink_buf = malloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1);
name_buf = malloc(N_ALIGN(PATH_MAX));
window = malloc(WSIZE);
if (!window || !header_buf || !symlink_buf || !name_buf)
error("can't allocate buffers");
state = Start;
this_header = 0;
while (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;
} else if (!*buf) {
buf++;
len--;
this_header++;
continue;
}
this_header = 0;
insize = len;
inbuf = buf;
inptr = 0;
outcnt = 0; /* bytes in output buffer */
bytes_out = 0;
crc = (ulg)0xffffffffL; /* shift register contents */
makecrc();
if (gunzip())
error("ungzip failed");
if (state != Reset)
error("junk in gzipped archive");
this_header = saved_offset + inptr;
buf += inptr;
len -= inptr;
}
free(window);
free(name_buf);
free(symlink_buf);
free(header_buf);
}
extern unsigned long __initramfs_start, __initramfs_end;
void __init populate_rootfs(void)
{
unpack_to_rootfs((void *) &__initramfs_start,
&__initramfs_end - &__initramfs_start);
}
......@@ -72,6 +72,7 @@ extern void pidhash_init(void);
extern void pte_chain_init(void);
extern void radix_tree_init(void);
extern void free_initmem(void);
extern void populate_rootfs(void);
#ifdef CONFIG_TC
extern void tc_init(void);
......@@ -433,6 +434,7 @@ asmlinkage void __init start_kernel(void)
vfs_caches_init(num_physpages);
radix_tree_init();
signals_init();
populate_rootfs();
#ifdef CONFIG_PROC_FS
proc_root_init();
#endif
......
include arch/$(ARCH)/Makefile
obj-y := initramfs_data.o
host-progs := gen_init_cpio
clean-files := initramfs_data.cpio.gz
$(obj)/initramfs_data.o: $(obj)/initramfs_data.cpio.gz
$(OBJCOPY) $(ARCHBLOBLFLAGS) \
--rename-section .data=.init.initramfs \
$(obj)/initramfs_data.cpio.gz $(obj)/initramfs_data.o
$(STRIP) -s $(obj)/initramfs_data.o
$(obj)/initramfs_data.cpio.gz: $(obj)/gen_init_cpio
( cd $(obj) ; ./gen_init_cpio | gzip -9c > initramfs_data.cpio.gz )
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
static unsigned int offset;
static unsigned int ino = 721;
static void push_rest(const char *name)
{
unsigned int name_len = strlen(name) + 1;
unsigned int tmp_ofs;
fputs(name, stdout);
putchar(0);
offset += name_len;
tmp_ofs = name_len + 110;
while (tmp_ofs & 3) {
putchar(0);
offset++;
tmp_ofs++;
}
}
static void push_hdr(const char *s)
{
fputs(s, stdout);
offset += 110;
}
static void cpio_trailer(void)
{
char s[256];
const char *name = "TRAILER!!!";
sprintf(s, "%s%08X%08X%08lX%08lX%08X%08lX"
"%08X%08X%08X%08X%08X%08X%08X",
"070701", /* magic */
0, /* ino */
0, /* mode */
(long) 0, /* uid */
(long) 0, /* gid */
1, /* nlink */
(long) 0, /* mtime */
0, /* filesize */
0, /* major */
0, /* minor */
0, /* rmajor */
0, /* rminor */
strlen(name) + 1, /* namesize */
0); /* chksum */
push_hdr(s);
push_rest(name);
while (offset % 512) {
putchar(0);
offset++;
}
}
static void cpio_mkdir(const char *name, unsigned int mode,
uid_t uid, gid_t gid)
{
char s[256];
time_t mtime = time(NULL);
sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
"%08X%08X%08X%08X%08X%08X%08X",
"070701", /* magic */
ino++, /* ino */
S_IFDIR | mode, /* mode */
(long) uid, /* uid */
(long) gid, /* gid */
2, /* nlink */
(long) mtime, /* mtime */
0, /* filesize */
3, /* major */
1, /* minor */
0, /* rmajor */
0, /* rminor */
strlen(name) + 1, /* namesize */
0); /* chksum */
push_hdr(s);
push_rest(name);
}
static void cpio_mknod(const char *name, unsigned int mode,
uid_t uid, gid_t gid, int dev_type,
unsigned int maj, unsigned int min)
{
char s[256];
time_t mtime = time(NULL);
if (dev_type == 'b')
mode |= S_IFBLK;
else
mode |= S_IFCHR;
sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
"%08X%08X%08X%08X%08X%08X%08X",
"070701", /* magic */
ino++, /* ino */
mode, /* mode */
(long) uid, /* uid */
(long) gid, /* gid */
1, /* nlink */
(long) mtime, /* mtime */
0, /* filesize */
3, /* major */
1, /* minor */
maj, /* rmajor */
min, /* rminor */
strlen(name) + 1, /* namesize */
0); /* chksum */
push_hdr(s);
push_rest(name);
}
int main (int argc, char *argv[])
{
cpio_mkdir("/dev", 0700, 0, 0);
cpio_mknod("/dev/console", 0600, 0, 0, 'c', 5, 1);
cpio_mkdir("/root", 0700, 0, 0);
cpio_trailer();
exit(0);
/* silence compiler warnings */
return 0;
(void) argc;
(void) argv;
}
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