Commit be3e0ada authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds

[PATCH] UCLINUX "flat" binary loader

This is much like the old m68k amiga/st loader world. Its a relocating
loader with optional compression. Shared libraries and A5 sharing stuff
is all handled by the userspace/libs
parent 3d8629b4
......@@ -30,6 +30,7 @@ obj-$(CONFIG_BINFMT_MISC) += binfmt_misc.o
obj-y += binfmt_script.o
obj-$(CONFIG_BINFMT_ELF) += binfmt_elf.o
obj-$(CONFIG_BINFMT_FLAT) += binfmt_flat.o
obj-$(CONFIG_FS_MBCACHE) += mbcache.o
obj-$(CONFIG_FS_POSIX_ACL) += posix_acl.o xattr_acl.o
......
/*
* linux/fs/binfmt_flat.c
*
* Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@uclinux.org>
* Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
*
* based heavily on:
*
* linux/fs/binfmt_aout.c:
* Copyright (C) 1991, 1992, 1996 Linus Torvalds
* linux/fs/binfmt_flat.c for 2.0 kernel
* Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
* JAN/99 -- coded full program relocation (gerg@snapgear.com)
*/
#include <linux/module.h>
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/a.out.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/personality.h>
#include <linux/init.h>
#include <linux/flat.h>
#include <asm/byteorder.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/unaligned.h>
#include <asm/cacheflush.h>
#undef DEBUG
#ifdef DEBUG
#define DBG_FLT(a...) printk(##a)
#else
#define DBG_FLT(a...)
#endif
static int load_flat_binary(struct linux_binprm *, struct pt_regs * regs);
static int load_flat_library(struct file*);
extern void dump_thread(struct pt_regs *, struct user *);
static struct linux_binfmt flat_format = {
NULL, THIS_MODULE, load_flat_binary, load_flat_library, NULL, PAGE_SIZE
};
/*
* create_flat_tables() parses the env- and arg-strings in new user
* memory and creates the pointer tables from them, and puts their
* addresses on the "stack", returning the new stack pointer value.
*/
static unsigned long create_flat_tables(
unsigned long pp,
struct linux_binprm * bprm)
{
unsigned long *argv,*envp;
unsigned long * sp;
char * p = (char*)pp;
int argc = bprm->argc;
int envc = bprm->envc;
char dummy;
sp = (unsigned long *) ((-(unsigned long)sizeof(char *))&(unsigned long) p);
sp -= envc+1;
envp = sp;
sp -= argc+1;
argv = sp;
put_user((unsigned long) envp, --sp);
put_user((unsigned long) argv, --sp);
put_user(argc,--sp);
current->mm->arg_start = (unsigned long) p;
while (argc-->0) {
put_user((unsigned long) p, argv++);
do {
get_user(dummy, p); p++;
} while (dummy);
}
put_user((unsigned long) NULL, argv);
current->mm->arg_end = current->mm->env_start = (unsigned long) p;
while (envc-->0) {
put_user((unsigned long)p, envp); envp++;
do {
get_user(dummy, p); p++;
} while (dummy);
}
put_user((unsigned long) NULL, envp);
current->mm->env_end = (unsigned long) p;
return (unsigned long)sp;
}
#ifdef CONFIG_BINFMT_ZFLAT
#include <linux/zlib.h>
#define LBUFSIZE 4000
/* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
#define RESERVED 0xC0 /* bit 6,7: reserved */
static int decompress_exec(
struct linux_binprm *bprm,
unsigned long offset,
char *dst,
long len,
int fd)
{
unsigned char *buf;
z_stream strm;
loff_t fpos;
int ret;
DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
memset(&strm, 0, sizeof(strm));
strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
if (strm.workspace == NULL) {
DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
return -ENOMEM;
}
buf = kmalloc(LBUFSIZE, GFP_KERNEL);
if (buf == NULL) {
DBG_FLT("binfmt_flat: no memory for read buffer\n");
return -ENOMEM;
}
/* Read in first chunk of data and parse gzip header. */
fpos = offset;
ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
strm.next_in = buf;
strm.avail_in = ret;
strm.total_in = 0;
/* Check minimum size -- gzip header */
if (ret < 10) {
DBG_FLT("binfmt_flat: file too small?\n");
return -ENOEXEC;
}
/* Check gzip magic number */
if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
DBG_FLT("binfmt_flat: unknown compression magic?\n");
return -ENOEXEC;
}
/* Check gzip method */
if (buf[2] != 8) {
DBG_FLT("binfmt_flat: unknown compression method?\n");
return -ENOEXEC;
}
/* Check gzip flags */
if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
(buf[3] & RESERVED)) {
DBG_FLT("binfmt_flat: unknown flags?\n");
return -ENOEXEC;
}
ret = 10;
if (buf[3] & EXTRA_FIELD)
ret += 2 + buf[10] + (buf[11] << 8);
if (buf[3] & ORIG_NAME) {
for (; (buf[ret] != 0); ret++)
;
}
if (buf[3] & COMMENT) {
for (; (buf[ret] != 0); ret++)
;
}
strm.next_in += ret;
strm.avail_in -= ret;
strm.next_out = dst;
strm.avail_out = len;
strm.total_out = 0;
if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
DBG_FLT("binfmt_flat: zlib init failed?\n");
return -ENOEXEC;
}
while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
if (ret == 0)
break;
if (ret >= (unsigned long) -4096)
break;
len -= ret;
strm.next_in = buf;
strm.avail_in = ret;
strm.total_in = 0;
}
if (ret < 0) {
DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
ret, strm.msg);
return -ENOEXEC;
}
zlib_inflateEnd(&strm);
kfree(buf);
kfree(strm.workspace);
return 0;
}
#endif /* CONFIG_BINFMT_ZFLAT */
static unsigned long
calc_reloc(unsigned long r, unsigned long text_len)
{
unsigned long addr;
if (r > current->mm->start_brk - current->mm->start_data + text_len) {
printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x), killing!\n",
(int) r,(int)(current->mm->start_brk-current->mm->start_code));
send_sig(SIGSEGV, current, 0);
return(current->mm->start_brk); /* return something safe to write to */
}
if (r < text_len) {
/* In text segment */
return r + current->mm->start_code;
}
/*
* we allow inclusive ranges here so that programs may do things
* like reference the end of data (_end) without failing these tests
*/
addr = r - text_len + current->mm->start_data;
if (addr >= current->mm->start_code &&
addr <= current->mm->start_code + text_len)
return(addr);
if (addr >= current->mm->start_data &&
addr <= current->mm->start_brk)
return(addr);
printk("BINFMT_FLAT: reloc addr outside text/data 0x%x "
"code(0x%x - 0x%x) data(0x%x - 0x%x) killing\n", (int) addr,
(int) current->mm->start_code,
(int) (current->mm->start_code + text_len),
(int) current->mm->start_data,
(int) current->mm->start_brk);
send_sig(SIGSEGV, current, 0);
return(current->mm->start_brk); /* return something safe to write to */
}
void old_reloc(unsigned long rl)
{
#ifdef DEBUG
char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
#endif
flat_v2_reloc_t r;
unsigned long *ptr;
r.value = rl;
#if defined(CONFIG_COLDFIRE)
ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
#else
ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
#endif
#ifdef DEBUG
printk("Relocation of variable at DATASEG+%x "
"(address %p, currently %x) into segment %s\n",
r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
#endif
switch (r.reloc.type) {
case OLD_FLAT_RELOC_TYPE_TEXT:
*ptr += current->mm->start_code;
break;
case OLD_FLAT_RELOC_TYPE_DATA:
*ptr += current->mm->start_data;
break;
case OLD_FLAT_RELOC_TYPE_BSS:
*ptr += current->mm->end_data;
break;
default:
printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
break;
}
#ifdef DEBUG
printk("Relocation became %x\n", (int)*ptr);
#endif
}
/*
* These are the functions used to load flat style executables and shared
* libraries. There is no binary dependent code anywhere else.
*/
static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
struct flat_hdr * hdr;
unsigned long textpos = 0, datapos = 0, result;
unsigned long text_len, data_len, bss_len, stack_len, flags;
unsigned long memp = 0, memkasked = 0; /* for finding the brk area */
unsigned long extra, rlim;
unsigned long p = bprm->p;
unsigned long *reloc = 0, *rp;
struct inode *inode;
int i, rev, relocs = 0;
loff_t fpos;
DBG_FLT("BINFMT_FLAT: Loading file: %x\n", bprm->file);
hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
inode = bprm->file->f_dentry->d_inode;
text_len = ntohl(hdr->data_start);
data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
stack_len = ntohl(hdr->stack_size);
relocs = ntohl(hdr->reloc_count);
flags = ntohl(hdr->flags);
rev = ntohl(hdr->rev);
/*
* We have to add the size of our arguments to our stack size
* otherwise it's too easy for users to create stack overflows
* by passing in a huge argument list. And yes, we have to be
* pedantic and include space for the argv/envp array as it may have
* a lot of entries.
*/
#define TOP_OF_ARGS (PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *))
stack_len += TOP_OF_ARGS - bprm->p; /* the strings */
stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
if (strncmp(hdr->magic, "bFLT", 4) ||
(rev != FLAT_VERSION && rev != OLD_FLAT_VERSION)) {
/*
* because a lot of people do not manage to produce good
* flat binaries, we leave this printk to help them realise
* the problem. We only print the error if its * not a script file
*/
if (strncmp(hdr->magic, "#!", 2))
printk("BINFMT_FLAT: bad magic/rev (0x%x, need 0x%x)\n",
rev, (int) FLAT_VERSION);
return -ENOEXEC;
}
/*
* fix up the flags for the older format, there were all kinds
* of endian hacks, this only works for the simple cases
*/
if (rev == OLD_FLAT_VERSION && flags)
flags = FLAT_FLAG_RAM;
#ifndef CONFIG_BINFMT_ZFLAT
if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
printk("Support for ZFLAT executables is not enabled.\n");
return -ENOEXEC;
}
#endif
/*
* Check initial limits. This avoids letting people circumvent
* size limits imposed on them by creating programs with large
* arrays in the data or bss.
*/
rlim = current->rlim[RLIMIT_DATA].rlim_cur;
if (rlim >= RLIM_INFINITY)
rlim = ~0;
if (data_len + bss_len > rlim)
return -ENOMEM;
/* Flush all traces of the currently running executable */
result = flush_old_exec(bprm);
if (result)
return result;
/* OK, This is the point of no return */
set_personality(PER_LINUX);
/*
* there are a couple of cases here, the seperate code/data
* case, and then the fully copied to RAM case which lumps
* it all together.
*/
if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
/*
* this should give us a ROM ptr, but if it doesn't we don't
* really care
*/
DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
down_write(&current->mm->mmap_sem);
textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, 0, 0);
up_write(&current->mm->mmap_sem);
if (!textpos || textpos >= (unsigned long) -4096) {
if (!textpos)
textpos = (unsigned long) -ENOMEM;
printk("Unable to mmap process text, errno %d\n", (int)-textpos);
}
extra = max(bss_len + stack_len, relocs * sizeof(unsigned long)),
down_write(&current->mm->mmap_sem);
datapos = do_mmap(0, 0, data_len + extra,
PROT_READ|PROT_WRITE|PROT_EXEC, 0, 0);
up_write(&current->mm->mmap_sem);
if (datapos == 0 || datapos >= (unsigned long)-4096) {
if (!datapos)
datapos = (unsigned long) -ENOMEM;
printk("Unable to allocate RAM for process data, errno %d\n",
(int)-datapos);
do_munmap(current->mm, textpos, text_len);
return datapos;
}
DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
data_len + bss_len + stack_len, datapos);
fpos = ntohl(hdr->data_start);
#ifdef CONFIG_BINFMT_ZFLAT
if (flags & FLAT_FLAG_GZDATA) {
result = decompress_exec(bprm, fpos, (char *) datapos,
data_len + (relocs * sizeof(unsigned long)), 0);
} else
#endif
{
result = bprm->file->f_op->read(bprm->file,
(char *) datapos, data_len + extra, &fpos);
}
if (result >= (unsigned long)-4096) {
printk("Unable to read data+bss, errno %d\n", (int)-result);
do_munmap(current->mm, textpos, text_len);
do_munmap(current->mm, datapos, data_len + extra);
return result;
}
reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
memp = datapos;
memkasked = data_len + extra;
} else {
/*
* calculate the extra space we need to map in
*/
extra = max(bss_len + stack_len, relocs * sizeof(unsigned long)),
down_write(&current->mm->mmap_sem);
textpos = do_mmap(0, 0, text_len + data_len + extra,
PROT_READ | PROT_EXEC | PROT_WRITE, 0, 0);
up_write(&current->mm->mmap_sem);
if (!textpos || textpos >= (unsigned long) -4096) {
if (!textpos)
textpos = (unsigned long) -ENOMEM;
printk("Unable to allocate RAM for process text/data, errno %d\n",
(int)-textpos);
}
datapos = textpos + ntohl (hdr->data_start);
reloc = (unsigned long *) (textpos + ntohl(hdr->reloc_start));
memp = textpos;
memkasked = text_len + data_len + extra;
#ifdef CONFIG_BINFMT_ZFLAT
/*
* load it all in and treat it like a RAM load from now on
*/
if (flags & FLAT_FLAG_GZIP) {
result = decompress_exec(bprm, sizeof (struct flat_hdr),
(((char *) textpos) + sizeof (struct flat_hdr)),
(text_len + data_len + (relocs * sizeof(unsigned long))
- sizeof (struct flat_hdr)),
0);
} else if (flags & FLAT_FLAG_GZDATA) {
fpos = 0;
result = bprm->file->f_op->read(bprm->file,
(char *) textpos, text_len, &fpos);
if (result < (unsigned long) -4096)
result = decompress_exec(bprm, text_len, (char *) datapos,
data_len + (relocs * sizeof(unsigned long)), 0);
}
else
#endif
{
fpos = 0;
result = bprm->file->f_op->read(bprm->file,
(char *) textpos, text_len + data_len + extra, &fpos);
}
if (result >= (unsigned long)-4096) {
printk("Unable to read code+data+bss, errno %d\n",(int)-result);
do_munmap(current->mm, textpos, text_len + data_len + extra);
return result;
}
}
DBG_FLT("Mapping is %x, Entry point is %x, data_start is %x\n",
textpos, ntohl(hdr->entry), ntohl(hdr->data_start));
current->mm->start_code = textpos + sizeof (struct flat_hdr);
current->mm->end_code = textpos + text_len;
current->mm->start_data = datapos;
current->mm->end_data = datapos + data_len;
/*
* set up the brk stuff (uses any slack left in data/bss/stack allocation
* We put the brk after the bss (between the bss and stack) like other
* platforms.
*/
current->mm->start_brk = datapos + data_len + bss_len;
current->mm->brk = (current->mm->start_brk + 3) & ~3;
current->mm->context.end_brk = memp + ksize((void *) memp) - stack_len;
current->mm->rss = 0;
DBG_FLT("Load %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
bprm->filename,
(int) current->mm->start_code, (int) current->mm->end_code,
(int) current->mm->start_data, (int) current->mm->end_data,
(int) current->mm->end_data, (int) current->mm->brk);
text_len -= sizeof(struct flat_hdr); /* the real code len */
/*
* We just load the allocations into some temporary memory to
* help simplify all this mumbo jumbo
*
* We've got two different sections of relocation entries.
* The first is the GOT which resides at the begining of the data segment
* and is terminated with a -1. This one can be relocated in place.
* The second is the extra relocation entries tacked after the image's
* data segment. These require a little more processing as the entry is
* really an offset into the image which contains an offset into the
* image.
*/
if (flags & FLAT_FLAG_GOTPIC) {
for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++)
*rp = calc_reloc(*rp, text_len);
}
/*
* Now run through the relocation entries.
* We've got to be careful here as C++ produces relocatable zero
* entries in the constructor and destructor tables which are then
* tested for being not zero (which will always occur unless we're
* based from address zero). This causes an endless loop as __start
* is at zero. The solution used is to not relocate zero addresses.
* This has the negative side effect of not allowing a global data
* reference to be statically initialised to _stext (I've moved
* __start to address 4 so that is okay).
*/
if (rev > OLD_FLAT_VERSION) {
for (i=0; i < relocs; i++) {
unsigned long addr;
/* Get the address of the pointer to be
relocated (of course, the address has to be
relocated first). */
rp = (unsigned long *) calc_reloc(ntohl(reloc[i]), text_len);
/* Get the pointer's value. */
addr = get_unaligned (rp);
if (addr != 0) {
/*
* Do the relocation. PIC relocs in the data section are
* already in target order
*/
addr = calc_reloc(
(flags & FLAT_FLAG_GOTPIC) ? addr : ntohl(addr),
text_len);
/* Write back the relocated pointer. */
put_unaligned (addr, rp);
}
}
} else {
for (i=0; i < relocs; i++)
old_reloc(ntohl(reloc[i]));
}
/* zero the BSS, BRK and stack areas */
memset((void*)(datapos + data_len), 0, bss_len +
(current->mm->context.end_brk - current->mm->start_brk) +
stack_len);
compute_creds(bprm);
current->flags &= ~PF_FORKNOEXEC;
flush_icache_range(current->mm->start_code, current->mm->end_code);
set_binfmt(&flat_format);
p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
DBG_FLT("p=%x\n", p);
/* copy the arg pages onto the stack, this could be more efficient :-) */
for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
* (char *) --p =
((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
current->mm->start_stack = (unsigned long) create_flat_tables(p, bprm);
DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
regs, textpos + ntohl(hdr->entry), current->mm->start_stack);
start_thread(regs,
textpos + ntohl(hdr->entry),
current->mm->start_stack);
if (current->ptrace & PT_PTRACED)
send_sig(SIGTRAP, current, 0);
return 0;
}
static int load_flat_library(struct file *file)
{
return(-ENOEXEC);
}
static int __init init_flat_binfmt(void)
{
return register_binfmt(&flat_format);
}
static void __exit exit_flat_binfmt(void)
{
unregister_binfmt(&flat_format);
}
EXPORT_NO_SYMBOLS;
module_init(init_flat_binfmt);
module_exit(exit_flat_binfmt);
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