FreeBSD-5.3/sys/kern/imgact_gzip.c
/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@FreeBSD.org> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
*
* This module handles execution of a.out files which have been run through
* "gzip". This saves diskspace, but wastes cpu-cycles and VM.
*
* TODO:
* text-segments should be made R/O after being filled
* is the vm-stuff safe ?
* should handle the entire header of gzip'ed stuff.
* inflate isn't quite reentrant yet...
* error-handling is a mess...
* so is the rest...
* tidy up unnecesary includes
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/imgact_gzip.c,v 1.51 2004/02/04 21:52:55 jhb Exp $");
#include <sys/param.h>
#include <sys/exec.h>
#include <sys/imgact.h>
#include <sys/imgact_aout.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mman.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/inflate.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
struct imgact_gzip {
struct image_params *ip;
struct exec a_out;
int error;
int gotheader;
int where;
u_char *inbuf;
u_long offset;
u_long output;
u_long len;
int idx;
u_long virtual_offset, file_offset, file_end, bss_size;
};
static int exec_gzip_imgact(struct image_params *imgp);
static int NextByte(void *vp);
static int do_aout_hdr(struct imgact_gzip *);
static int Flush(void *vp, u_char *, u_long siz);
static int
exec_gzip_imgact(imgp)
struct image_params *imgp;
{
int error, error2 = 0;
const u_char *p = (const u_char *) imgp->image_header;
struct imgact_gzip igz;
struct inflate infl;
struct vmspace *vmspace;
/* If these four are not OK, it isn't a gzip file */
if (p[0] != 0x1f)
return -1; /* 0 Simply magic */
if (p[1] != 0x8b)
return -1; /* 1 Simply magic */
if (p[2] != 0x08)
return -1; /* 2 Compression method */
if (p[9] != 0x03)
return -1; /* 9 OS compressed on */
/*
* If this one contains anything but a comment or a filename marker,
* we don't want to chew on it
*/
if (p[3] & ~(0x18))
return ENOEXEC; /* 3 Flags */
/* These are of no use to us */
/* 4-7 Timestamp */
/* 8 Extra flags */
bzero(&igz, sizeof igz);
bzero(&infl, sizeof infl);
infl.gz_private = (void *) &igz;
infl.gz_input = NextByte;
infl.gz_output = Flush;
igz.ip = imgp;
igz.idx = 10;
if (p[3] & 0x08) { /* skip a filename */
while (p[igz.idx++])
if (igz.idx >= PAGE_SIZE)
return ENOEXEC;
}
if (p[3] & 0x10) { /* skip a comment */
while (p[igz.idx++])
if (igz.idx >= PAGE_SIZE)
return ENOEXEC;
}
igz.len = imgp->attr->va_size;
error = inflate(&infl);
/*
* The unzipped file may not even have been long enough to contain
* a header giving Flush() a chance to return error. Check for this.
*/
if ( !igz.gotheader )
return ENOEXEC;
if ( !error ) {
vmspace = imgp->proc->p_vmspace;
error = vm_map_protect(&vmspace->vm_map,
(vm_offset_t) vmspace->vm_taddr,
(vm_offset_t) (vmspace->vm_taddr +
(vmspace->vm_tsize << PAGE_SHIFT)) ,
VM_PROT_READ|VM_PROT_EXECUTE,0);
}
if (igz.inbuf) {
error2 =
vm_map_remove(kernel_map, (vm_offset_t) igz.inbuf,
(vm_offset_t) igz.inbuf + PAGE_SIZE);
}
if (igz.error || error || error2) {
printf("Output=%lu ", igz.output);
printf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
error, igz.error, error2, igz.where);
}
if (igz.error)
return igz.error;
if (error)
return ENOEXEC;
if (error2)
return error2;
return 0;
}
static int
do_aout_hdr(struct imgact_gzip * gz)
{
int error;
struct vmspace *vmspace;
vm_offset_t vmaddr;
/*
* Set file/virtual offset based on a.out variant. We do two cases:
* host byte order and network byte order (for NetBSD compatibility)
*/
switch ((int) (gz->a_out.a_magic & 0xffff)) {
case ZMAGIC:
gz->virtual_offset = 0;
if (gz->a_out.a_text) {
gz->file_offset = PAGE_SIZE;
} else {
/* Bill's "screwball mode" */
gz->file_offset = 0;
}
break;
case QMAGIC:
gz->virtual_offset = PAGE_SIZE;
gz->file_offset = 0;
break;
default:
/* NetBSD compatibility */
switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
case ZMAGIC:
case QMAGIC:
gz->virtual_offset = PAGE_SIZE;
gz->file_offset = 0;
break;
default:
gz->where = __LINE__;
return (-1);
}
}
gz->bss_size = roundup(gz->a_out.a_bss, PAGE_SIZE);
/*
* Check various fields in header for validity/bounds.
*/
if ( /* entry point must lay with text region */
gz->a_out.a_entry < gz->virtual_offset ||
gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
/* text and data size must each be page rounded */
gz->a_out.a_text & PAGE_MASK || gz->a_out.a_data & PAGE_MASK) {
gz->where = __LINE__;
return (-1);
}
/*
* text/data/bss must not exceed limits
*/
PROC_LOCK(gz->ip->proc);
if ( /* text can't exceed maximum text size */
gz->a_out.a_text > maxtsiz ||
/* data + bss can't exceed rlimit */
gz->a_out.a_data + gz->bss_size >
lim_cur(gz->ip->proc, RLIMIT_DATA)) {
PROC_UNLOCK(gz->ip->proc);
gz->where = __LINE__;
return (ENOMEM);
}
PROC_UNLOCK(gz->ip->proc);
/* Find out how far we should go */
gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
/* copy in arguments and/or environment from old process */
error = exec_extract_strings(gz->ip);
if (error) {
gz->where = __LINE__;
return (error);
}
/*
* Destroy old process VM and create a new one (with a new stack)
*/
exec_new_vmspace(gz->ip, &aout_sysvec);
vmspace = gz->ip->proc->p_vmspace;
vmaddr = gz->virtual_offset;
error = vm_mmap(&vmspace->vm_map,
&vmaddr,
gz->a_out.a_text + gz->a_out.a_data,
VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
0,
0);
if (error) {
gz->where = __LINE__;
return (error);
}
if (gz->bss_size != 0) {
/*
* Allocate demand-zeroed area for uninitialized data.
* "bss" = 'block started by symbol' - named after the
* IBM 7090 instruction of the same name.
*/
vmaddr = gz->virtual_offset + gz->a_out.a_text +
gz->a_out.a_data;
error = vm_map_find(&vmspace->vm_map,
NULL,
0,
&vmaddr,
gz->bss_size,
FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
if (error) {
gz->where = __LINE__;
return (error);
}
}
/* Fill in process VM information */
vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
vmspace->vm_daddr = (caddr_t) (uintptr_t)
(gz->virtual_offset + gz->a_out.a_text);
/* Fill in image_params */
gz->ip->interpreted = 0;
gz->ip->entry_addr = gz->a_out.a_entry;
gz->ip->proc->p_sysent = &aout_sysvec;
return 0;
}
static int
NextByte(void *vp)
{
int error;
struct imgact_gzip *igz = (struct imgact_gzip *) vp;
if (igz->idx >= igz->len) {
igz->where = __LINE__;
return GZ_EOF;
}
if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
return igz->inbuf[(igz->idx++) - igz->offset];
}
if (igz->inbuf) {
error = vm_map_remove(kernel_map, (vm_offset_t) igz->inbuf,
(vm_offset_t) igz->inbuf + PAGE_SIZE);
if (error) {
igz->where = __LINE__;
igz->error = error;
return GZ_EOF;
}
}
igz->offset = igz->idx & ~PAGE_MASK;
error = vm_mmap(kernel_map, /* map */
(vm_offset_t *) & igz->inbuf, /* address */
PAGE_SIZE, /* size */
VM_PROT_READ, /* protection */
VM_PROT_READ, /* max protection */
0, /* flags */
(caddr_t) igz->ip->vp, /* vnode */
igz->offset); /* offset */
if (error) {
igz->where = __LINE__;
igz->error = error;
return GZ_EOF;
}
return igz->inbuf[(igz->idx++) - igz->offset];
}
static int
Flush(void *vp, u_char * ptr, u_long siz)
{
struct imgact_gzip *gz = (struct imgact_gzip *) vp;
u_char *p = ptr, *q;
int i;
/* First, find an a.out-header. */
if (gz->output < sizeof gz->a_out) {
q = (u_char *) & gz->a_out;
i = min(siz, sizeof gz->a_out - gz->output);
bcopy(p, q + gz->output, i);
gz->output += i;
p += i;
siz -= i;
if (gz->output == sizeof gz->a_out) {
gz->gotheader = 1;
i = do_aout_hdr(gz);
if (i == -1) {
if (!gz->where)
gz->where = __LINE__;
gz->error = ENOEXEC;
return ENOEXEC;
} else if (i) {
gz->where = __LINE__;
gz->error = i;
return ENOEXEC;
}
if (gz->file_offset == 0) {
q = (u_char *) (uintptr_t) gz->virtual_offset;
copyout(&gz->a_out, q, sizeof gz->a_out);
}
}
}
/* Skip over zero-padded first PAGE if needed */
if (gz->output < gz->file_offset &&
gz->output + siz > gz->file_offset) {
i = min(siz, gz->file_offset - gz->output);
gz->output += i;
p += i;
siz -= i;
}
if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
i = min(siz, gz->file_end - gz->output);
q = (u_char *) (uintptr_t)
(gz->virtual_offset + gz->output - gz->file_offset);
copyout(p, q, i);
gz->output += i;
p += i;
siz -= i;
}
gz->output += siz;
return 0;
}
/*
* Tell kern_execve.c about it, with a little help from the linker.
*/
static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
EXEC_SET(execgzip, gzip_execsw);