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freebsd/usr.bin/genassym/genassym.c
1999-12-23 11:07:45 +00:00

272 lines
6.7 KiB
C

/*-
* Copyright (c) 1999 Marcel Moolenaar
* 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
* in this position and unchanged.
* 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 withough 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#if defined(arch_i386)
#include <sys/elf32.h>
#define __ELF_WORD_SIZE 32
#elif defined(arch_alpha)
#include <sys/elf64.h>
#define __ELF_WORD_SIZE 64
#else
#error unknown or missing architecture
#endif
#include <sys/elf_generic.h>
#include <err.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
const char s_data[] = ".data";
const char s_strtab[] = ".strtab";
const char s_symtab[] = ".symtab";
const char assym[] = "assym_";
int fd;
char *objfile;
Elf_Ehdr ehdr;
Elf_Shdr *shdr;
char *shstr;
int
my_byte_order(void)
{
static unsigned short s = 0xbbaa;
int byte0;
byte0 = *(unsigned char *)&s;
if (byte0 == 0xaa)
return (ELFDATA2LSB);
else if (byte0 == 0xbb)
return (ELFDATA2MSB);
return (ELFDATANONE);
}
void *
read_section(int index)
{
void *buf;
size_t size;
ssize_t bytes;
size = shdr[index].sh_size;
buf = malloc(size);
if (buf == NULL)
return (NULL);
if (lseek(fd, shdr[index].sh_offset, SEEK_SET) == -1)
return (NULL);
bytes = read(fd, buf, size);
if (bytes == -1)
return (NULL);
if (bytes != size)
warnx("%s: section %d partially read", objfile, index);
return (buf);
}
int section_index(const char *section)
{
int i;
for (i = 1; i < ehdr.e_shnum; i++)
if (!strcmp(section, shstr + shdr[i].sh_name))
return (i);
return (-1);
}
char *
filter(char *name)
{
char *dot;
name += sizeof(assym) - 1;
dot = strchr(name, '.');
if (dot != NULL)
*dot = '\0';
return (name);
}
void usage(void)
{
fprintf(stderr, "usage: genassym [-o outfile] objfile\n");
exit(1);
/* NOT REACHED */
}
int
main(int argc, char *argv[])
{
Elf_Sym *sym;
char *data, *name, *symbols;
char *outfile;
void *valp;
size_t size;
ssize_t bytes;
int ch, i, numsym, warn_ld_bug;
int si_data, si_strtab, si_symtab;
u_int64_t value;
outfile = NULL;
warn_ld_bug = 1;
while ((ch = getopt(argc, argv, "o:")) != -1) {
switch (ch) {
case 'o':
outfile = optarg;
break;
default:
usage();
/* NOT REACHED */
}
}
argc -= optind;
argv += optind;
if (argc == 0) {
usage();
/* NOT REACHED */
}
if (argc > 1)
warnx("ignoring trailing arguments");
objfile = argv[0];
fd = open(objfile, O_RDONLY);
if (fd == -1)
err(1, "%s", objfile);
bytes = read(fd, &ehdr, sizeof(ehdr));
if (bytes == -1)
err(1, "%s", objfile);
if (bytes != sizeof(ehdr) ||
ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
ehdr.e_ident[EI_MAG3] != ELFMAG3)
errx(1, "%s: not an ELF file", objfile);
if (ehdr.e_ident[EI_VERSION] != EV_CURRENT)
errx(1, "%s: unsupported ELF version", objfile);
if (ehdr.e_ident[EI_DATA] != my_byte_order())
errx(1, "%s: unsupported byte order", objfile);
if (ehdr.e_shoff == 0)
errx(1, "%s: no section table", objfile);
if (ehdr.e_shstrndx == SHN_UNDEF)
errx(1, "%s: no section name string table", objfile);
size = sizeof(*shdr) * ehdr.e_shnum;
shdr = malloc(size);
if (shdr == NULL)
err(1, "malloc");
if (lseek(fd, ehdr.e_shoff, SEEK_SET) == -1)
err(1, "%s", objfile);
bytes = read(fd, shdr, size);
if (bytes == -1)
err(1, "%s", objfile);
if (bytes != size)
errx(1, "%s: truncated section table", objfile);
shstr = read_section(ehdr.e_shstrndx);
if (shstr == NULL)
err(1, "%s[%d]", objfile, ehdr.e_shstrndx);
si_data = section_index(s_data);
if (si_data == -1)
errx(1, "%s: section %s not present", objfile, s_data);
data = read_section(si_data);
if (data == NULL)
err(1, "%s[%d]", objfile, si_data);
si_strtab = section_index(s_strtab);
if (si_strtab == -1)
errx(1, "%s: section %s not present", objfile, s_strtab);
symbols = read_section(si_strtab);
if (symbols == NULL)
err(1, "%s[%d]", objfile, si_strtab);
si_symtab = section_index(s_symtab);
if (si_symtab == -1)
errx(1, "%s: section %s not present", objfile, s_symtab);
sym = read_section(si_symtab);
if (sym == NULL)
err(1, "%s[%d]", objfile, si_symtab);
numsym = shdr[si_symtab].sh_size / sizeof(*sym);
if (outfile != NULL)
freopen(outfile, "w", stdout);
for (i = 0; i < numsym; i++) {
name = symbols + sym[i].st_name;
if (sym[i].st_shndx == si_data &&
!strncmp(name, assym, sizeof(assym) - 1)) {
valp = (void*)(data + sym[i].st_value);
/*
* XXX - ld(1) on Alpha doesn't store the size of
* the symbol in the object file. The following
* fix handles this case quite genericly. It
* assumes that the symbols have the same size as
* a word on that architecture, determined by the
* word size in the ELF object file.
*/
if (sym[i].st_size == 0) {
sym[i].st_size = __ELF_WORD_SIZE >> 3;
if (warn_ld_bug) {
warnx("%s: symbol sizes not properly"
" set", objfile);
warn_ld_bug = 0;
}
}
switch (sym[i].st_size) {
case 1:
value = *(u_int8_t*)valp;
break;
case 2:
value = *(u_int16_t*)valp;
break;
case 4:
value = *(u_int32_t*)valp;
break;
case 8:
value = *(u_int64_t*)valp;
break;
default:
warnx("unsupported size (%lld) for symbol %s",
(long long)sym[i].st_size, filter(name));
continue;
}
fprintf(stdout, "#define\t%s 0x%llx\n", filter(name),
(long long)value);
}
}
return (0);
}