NetBSD/usr.sbin/dbsym/dbsym.c

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/*
* Copyright (c) 1994 Gordon W. Ross
* All rights reserved.
*
* 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.
*
* $Id: dbsym.c,v 1.10 1994/06/27 22:21:20 gwr Exp $
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*/
/* Copy the symbol table into the space reserved for it. */
#include <sys/types.h>
#include <sys/file.h>
#include <sys/mman.h>
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#include <stdio.h>
#include <a.out.h>
extern off_t lseek();
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struct exec head;
char *file;
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/* Virtual addresses of the symbols we frob. */
long db_symtab_va, db_symtabsize_va;
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/* Offsets relative to start of data segment. */
long db_symtab_off, db_symtabsize_off;
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/* value in the location at db_symtabsize_off */
int db_symtabsize_val;
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/* pointers to pieces of mapped file */
char *dataseg;
char *symbols;
char *strings;
int *strtab;
/* and lengths */
int strtab_len;
int file_len;
int data_off;
int data_pgoff;
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main(argc,argv)
char **argv;
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{
int fd, n;
int *ip;
char *cp;
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if (argc < 2) {
printf("%s: missing file name\n", argv[0]);
exit(1);
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}
file = argv[1];
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fd = open(file, O_RDWR);
if (fd < 0) {
perror(file);
exit(1);
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}
n = read(fd, &head, sizeof(head));
if (n < sizeof(head)) {
printf("%s: reading header\n", file);
exit(1);
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}
file_len = lseek(fd, (off_t)0, 2);
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if (N_BADMAG(head)) {
printf("%s: bad magic number\n");
exit(1);
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}
#ifdef DEBUG
printf(" text: %9d\n", head.a_text);
printf(" data: %9d\n", head.a_data);
printf(" bss: %9d\n", head.a_bss);
printf(" syms: %9d\n", head.a_syms);
printf("entry: 0x%08X\n", head.a_entry);
printf("trsiz: %9d\n", head.a_trsize);
printf("drsiz: %9d\n", head.a_drsize);
#endif
if (head.a_syms <= 0) {
printf("%s: no symbols\n", file);
exit(1);
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}
if (head.a_trsize ||
head.a_drsize)
{
printf("%s: has relocations\n");
exit(1);
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}
find_db_symtab(file);
/*
* Map in the file from start of data to EOF.
* The file offset needs to be page aligned.
*/
data_off = N_DATOFF(head);
data_pgoff = N_PAGSIZ(head) - 1;
data_pgoff &= data_off;
data_off -= data_pgoff;
dataseg = mmap(NULL, /* any address is ok */
file_len - data_off, /* length */
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd, data_off);
if ((long)dataseg == -1) {
printf("%s: can not map data seg\n", file);
perror(file);
exit(1);
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}
dataseg += data_pgoff;
symbols = dataseg + head.a_data;
strings = symbols + head.a_syms;
/* Find the string table length (first word after symtab). */
strtab_len = *((int*)strings);
#ifdef DEBUG
printf("strtab_len: %d\n", strtab_len);
#endif
/*
* Find value in the location: db_symtabsize
*/
ip = (int*) (dataseg + db_symtabsize_off);
db_symtabsize_val = *ip;
#ifdef DEBUG
printf("db_symtabsize val: 0x%08X (%d)\n",
db_symtabsize_val, db_symtabsize_val);
#endif
/* Is there room for the symbols + strings? */
if (db_symtabsize_val < (head.a_syms + strtab_len)) {
printf("%s: symbol space too small (%d < %d)\n", argv[0],
db_symtabsize_val, (head.a_syms + strtab_len));
exit(1);
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}
printf("Symbols use %d of %d bytes available (%d%%)\n",
head.a_syms + strtab_len,
db_symtabsize_val,
(head.a_syms + strtab_len) * 100 /
db_symtabsize_val);
/*
* Copy the symbol table and string table.
*/
#ifdef DEBUG
printf("copying symbol table...\n");
#endif
ip = (int*) (dataseg + db_symtab_off);
/* Write symtab length */
*ip++ = head.a_syms;
memcpy((char*)ip, symbols, head.a_syms + strtab_len);
msync(dataseg - data_pgoff, file_len - data_off
#ifdef sun
,0
#endif
);
#ifdef DEBUG
printf("...done\n");
#endif
close(fd);
exit(0);
}
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/*
* Find locations of the symbols to patch.
*/
struct nlist wantsyms[] = {
{ "_db_symtabsize", 0 },
{ "_db_symtab", 0 },
{ NULL, 0 },
};
find_db_symtab(file)
char *file;
{
int data_va;
int std_entry;
if (nlist(file, wantsyms)) {
printf("%s: no db_symtab symbols?\n", file);
exit(1);
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}
std_entry = N_TXTADDR(head) +
(head.a_entry & (N_PAGSIZ(head)-1));
data_va = N_DATADDR(head);
if (head.a_entry != std_entry) {
printf("%s: warning: non-standard entry point: 0x%08x\n",
file, head.a_entry);
printf("\texpecting entry=0x%X\n", std_entry);
data_va += (head.a_entry - std_entry);
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}
db_symtabsize_off = wantsyms[0].n_value - data_va;
db_symtab_off = wantsyms[1].n_value - data_va;
#ifdef DEBUG
printf(".data segment va: 0x%08X\n", data_va);
printf("db_symtabsize va: 0x%08X\n", wantsyms[0].n_value);
printf("db_symtab va: 0x%08X\n", wantsyms[1].n_value);
printf("db_symtabsize off: 0x%08X\n", db_symtabsize_off);
printf("db_symtab off: 0x%08X\n", db_symtab_off);
#endif
/*
* Sanity check locations of db_* symbols
*/
if (db_symtab_off < 0 || db_symtab_off >= head.a_data) {
printf("%s: db_symtab not in data segment?\n", file);
exit(1);
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}
if (db_symtabsize_off < 0 || db_symtabsize_off >= head.a_data) {
printf("%s: db_symtabsize not in data segment?\n", file);
exit(1);
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}
}