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/* $OpenBSD: rdsetroot.c,v 1.2 1997/11/26 02:32:28 deraadt Exp $ */
/* $NetBSD: rdsetroot.c,v 1.2 1995/10/13 16:38:39 gwr Exp $ */
/*
* Copyright (c) 1994 Gordon W. Ross
* All rights reserved.
*
* ELF modifications Copyright (c) 1997 Per Fogelstrom.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copy a ramdisk image into the space reserved for it.
* Kernel variables: rd_root_size, rd_root_image
*/
#include <sys/types.h>
#include <sys/file.h>
#include <sys/mman.h>
#include <stdio.h>
#include <nlist.h>
#include <sys/exec_elf.h>
extern off_t lseek();
char *file;
/* Virtual addresses of the symbols we frob. */
long rd_root_image_va, rd_root_size_va;
/* Offsets relative to start of data segment. */
long rd_root_image_off, rd_root_size_off;
/* value in the location at rd_root_size_off */
int rd_root_size_val;
/* pointers to pieces of mapped file */
char *dataseg;
/* parameters to mmap digged out from program header */
int mmap_offs;
int mmap_size;
main(argc,argv)
char **argv;
{
int fd, n;
int found;
int *ip;
char *cp;
Elf32_Ehdr eh;
Elf32_Phdr *ph;
int phsize;
if (argc < 2) {
printf("%s: missing file name\n", argv[0]);
exit(1);
}
file = argv[1];
fd = open(file, O_RDWR);
if (fd < 0) {
perror(file);
exit(1);
}
n = read(fd, &eh, sizeof(eh));
if (n < sizeof(eh)) {
printf("%s: reading header\n", file);
exit(1);
}
if (!IS_ELF(eh)) {
printf("%s: not elf\n", file);
exit(1);
}
phsize = eh.e_phnum * sizeof(Elf32_Phdr);
ph = (Elf32_Phdr *)malloc(phsize);
lseek(fd, eh.e_phoff, 0);
if(read(fd, (char *)ph, phsize) != phsize) {
printf("%s: can't read phdr area\n", file);
exit(1);
}
found = 0;
for(n = 0; n < eh.e_phnum && !found; n++) {
if(ph[n].p_type == PT_LOAD) {
found = find_rd_root_image(file, &eh, &ph[n]);
}
}
if(!found) {
printf("%s: can't locate space for rd_root_image!", file);
exit(1);
}
/*
* Map in the whole data segment.
* The file offset needs to be page aligned.
*/
dataseg = mmap(NULL, /* any address is ok */
mmap_size, /* length */
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd, mmap_offs);
if ((long)dataseg == -1) {
printf("%s: can not map data seg\n", file);
perror(file);
exit(1);
}
/*
* Find value in the location: rd_root_size
*/
ip = (int*) (dataseg + rd_root_size_off);
rd_root_size_val = *ip;
#ifdef DEBUG
printf("rd_root_size val: 0x%08X (%d blocks)\n",
rd_root_size_val, (rd_root_size_val >> 9));
#endif
/*
* Copy the symbol table and string table.
*/
#ifdef DEBUG
printf("copying root image...\n");
#endif
n = read(0, dataseg + rd_root_image_off,
rd_root_size_val);
if (n < 0) {
perror("read");
exit(1);
}
msync(dataseg, mmap_size, 0);
#ifdef DEBUG
printf("...copied %d bytes\n", n);
#endif
close(fd);
exit(0);
}
/*
* Find locations of the symbols to patch.
*/
struct nlist wantsyms[] = {
{ "_rd_root_size", 0 },
{ "_rd_root_image", 0 },
{ NULL, 0 },
};
int
find_rd_root_image(file, eh, ph)
char *file;
Elf32_Ehdr *eh;
Elf32_Phdr *ph;
{
int data_va;
int std_entry;
int kernel_start;
int kernel_size;
if (nlist(file, wantsyms)) {
printf("%s: no rd_root_image symbols?\n", file);
exit(1);
}
kernel_start = ph->p_paddr;
kernel_size = ph->p_filesz;
rd_root_size_off = wantsyms[0].n_value - kernel_start;
rd_root_image_off = wantsyms[1].n_value - kernel_start;
#ifdef DEBUG
printf("rd_root_size_off = 0x%x\n", rd_root_size_off);
printf("rd_root_image_off = 0x%x\n", rd_root_image_off);
#endif
/*
* Sanity check locations of db_* symbols
*/
if (rd_root_image_off < 0 || rd_root_image_off >= kernel_size) {
return(0);
}
if (rd_root_size_off < 0 || rd_root_size_off >= kernel_size) {
printf("%s: rd_root_size not in data segment?\n", file);
return(0);
}
mmap_offs = ph->p_offset;
mmap_size = kernel_size;
return(1);
}
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