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NetBSD/gnu/usr.sbin/dbsym/dbsym.c

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/* $NetBSD: dbsym.c,v 1.6 2003/03/06 00:26:10 thorpej Exp $ */
/*
* Copyright (c) 2001 Simon Burge (for Wasabi Systems)
* Copyright (c) 1996 Christopher G. Demetriou
* 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: LICENSE_GC,v 1.1 2001/10/01 23:24:05 cgd Exp>>
*/
#include <sys/cdefs.h>
#if defined(__COPYRIGHT) && !defined(lint)
__COPYRIGHT(
"@(#) Copyright (c) 1996 Christopher G. Demetriou, 2001 Simon Burge.\
All rights reserved.\n");
#endif /* not lint */
#if defined(__RCSID) && !defined(lint)
__RCSID("$NetBSD: dbsym.c,v 1.6 2003/03/06 00:26:10 thorpej Exp $");
#endif /* not lint */
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <bfd.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/* BFD ELF headers */
#include <elf/common.h>
#include <elf/external.h>
struct symbols {
char *name;
size_t offset;
} db_symtab_symbols[] = {
#define X_DB_SYMTAB 0
{ "_db_symtab", 0 },
#define X_DB_SYMTABSIZE 1
{ "_db_symtabsize", 0 },
{ NULL, 0 }
};
int main(int, char **);
void usage(void) __attribute__((noreturn));
int find_symtab(bfd *, struct symbols *);
int load_symtab(bfd *, int fd, char **, u_int32_t *);
int verbose;
int
main(int argc, char **argv)
{
int ch, kfd;
struct stat ksb;
size_t symtab_offset;
u_int32_t symtab_space, symtabsize;
const char *kfile;
char *bfdname, *mappedkfile, *symtab;
bfd *abfd;
setprogname(argv[0]);
bfdname = NULL;
while ((ch = getopt(argc, argv, "b:v")) != -1)
switch (ch) {
case 'b':
bfdname = optarg;
break;
case 'v':
verbose = 1;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (argc != 1)
usage();
kfile = argv[0];
if ((kfd = open(kfile, O_RDWR, 0)) == -1)
err(1, "open %s", kfile);
bfd_init();
if ((abfd = bfd_fdopenr(kfile, bfdname, kfd)) == NULL) {
bfd_perror("open");
exit(1);
}
if (!bfd_check_format(abfd, bfd_object)) {
bfd_perror("check format");
exit(1);
}
if (!(bfd_get_file_flags(abfd) & HAS_SYMS))
errx(1, "no symbol table in %s", kfile);
if (find_symtab(abfd, db_symtab_symbols) != 0)
errx(1, "could not find SYMTAB_SPACE in %s", kfile);
if (verbose)
fprintf(stderr, "got SYMTAB_SPACE symbols from %s\n", kfile);
if (load_symtab(abfd, kfd, &symtab, &symtabsize) != 0)
errx(1, "could not load symbol table from %s", kfile);
if (verbose)
fprintf(stderr, "loaded symbol table from %s\n", kfile);
if (fstat(kfd, &ksb) == -1)
err(1, "fstat %s", kfile);
if (ksb.st_size != (size_t)ksb.st_size)
errx(1, "%s too big to map", kfile);
if ((mappedkfile = mmap(NULL, ksb.st_size, PROT_READ | PROT_WRITE,
MAP_FILE | MAP_SHARED, kfd, 0)) == (caddr_t)-1)
err(1, "mmap %s", kfile);
if (verbose)
fprintf(stderr, "mapped %s\n", kfile);
symtab_offset = db_symtab_symbols[X_DB_SYMTAB].offset;
symtab_space = bfd_get_32(abfd,
&mappedkfile[db_symtab_symbols[X_DB_SYMTABSIZE].offset]);
if (symtabsize > symtab_space)
errx(1, "symbol table (%u bytes) too big for buffer (%u bytes)",
symtabsize, symtab_space);
if (verbose)
fprintf(stderr, "symtab size %d, space available %d\n",
symtabsize, symtab_space);
memcpy(mappedkfile + symtab_offset, symtab, symtabsize);
if (verbose)
fprintf(stderr, "done copying image to file offset %#lx\n",
(long)db_symtab_symbols[X_DB_SYMTAB].offset);
bfd_put_32(abfd, symtabsize,
&mappedkfile[db_symtab_symbols[X_DB_SYMTABSIZE].offset]);
munmap(mappedkfile, ksb.st_size);
close(kfd);
if (verbose)
fprintf(stderr, "exiting\n");
bfd_close_all_done(abfd);
exit(0);
}
void
usage(void)
{
const char **list;
fprintf(stderr,
"usage: %s [-b bfdname] [-v] kernel_file\n",
getprogname());
fprintf(stderr, "supported targets:");
for (list = bfd_target_list(); *list != NULL; list++)
fprintf(stderr, " %s", *list);
fprintf(stderr, "\n");
exit(1);
}
int
find_symtab(bfd *abfd, struct symbols *symbols)
{
long i;
long storage_needed;
long number_of_symbols;
asymbol **symbol_table = NULL;
struct symbols *s;
storage_needed = bfd_get_symtab_upper_bound(abfd);
if (storage_needed <= 0)
return (1);
if ((symbol_table = (asymbol **)malloc(storage_needed)) == NULL)
return (1);
number_of_symbols = bfd_canonicalize_symtab(abfd, symbol_table);
if (number_of_symbols <= 0) {
free(symbol_table);
return (1);
}
for (i = 0; i < number_of_symbols; i++) {
for (s = symbols; s->name != NULL; s++) {
const char *sym = symbol_table[i]->name;
/*
* match symbol prefix '_' or ''.
* XXX: use bfd_get_symbol_leading_char() here?
*/
if (!strcmp(s->name, sym) ||
!strcmp(s->name + 1, sym)) {
s->offset = (size_t)
(symbol_table[i]->section->filepos
+ symbol_table[i]->value);
}
}
}
free(symbol_table);
for (s = symbols; s->name != NULL; s++) {
if (s->offset == 0)
return (1);
}
return (0);
}
/* --------------------------- ELF gunk follows --------------------------- */
/*
* The format of the symbols loaded by the boot program is:
*
* Elf exec header
* first section header
* . . .
* . . .
* last section header
* first symbol or string table section
* . . .
* . . .
* last symbol or string table section
*/
/* Note elftype is local to load_symtab()... */
#define ELF_TYPE_64 0x01
#define ISELF64 (elftype & ELF_TYPE_64)
/*
* Field sizes for the Elf exec header:
*
* ELF32 ELF64
*
* unsigned char e_ident[ELF_NIDENT]; # Id bytes
* 16 16 e_type; # file type
* 16 16 e_machine; # machine type
* 32 32 e_version; # version number
* 32 64 e_entry; # entry point
* 32 64 e_phoff; # Program hdr offset
* 32 64 e_shoff; # Section hdr offset
* 32 32 e_flags; # Processor flags
* 16 16 e_ehsize; # sizeof ehdr
* 16 16 e_phentsize; # Program header entry size
* 16 16 e_phnum; # Number of program headers
* 16 16 e_shentsize; # Section header entry size
* 16 16 e_shnum; # Number of section headers
* 16 16 e_shstrndx; # String table index
*/
typedef union {
Elf32_External_Ehdr e32hdr;
Elf64_External_Ehdr e64hdr;
char e_ident[16]; /* XXX MAGIC NUMBER */
} elf_ehdr;
#define e32_hdr ehdr.e32hdr
#define e64_hdr ehdr.e64hdr
/*
* Field sizes for Elf section headers
*
* ELF32 ELF64
*
* 32 32 sh_name; # section name (.shstrtab index)
* 32 32 sh_type; # section type
* 32 64 sh_flags; # section flags
* 32 64 sh_addr; # virtual address
* 32 64 sh_offset; # file offset
* 32 64 sh_size; # section size
* 32 32 sh_link; # link to another
* 32 32 sh_info; # misc info
* 32 64 sh_addralign; # memory alignment
* 32 64 sh_entsize; # table entry size
*/
/* Extract a 32 bit field from Elf32_Shdr */
#define SH_E32_32(x, n) bfd_get_32(abfd, s32hdr[(x)].n)
/* Extract a 32 bit field from Elf64_Shdr */
#define SH_E64_32(x, n) bfd_get_32(abfd, s64hdr[(x)].n)
/* Extract a 64 bit field from Elf64_Shdr */
#define SH_E64_64(x, n) bfd_get_64(abfd, s64hdr[(x)].n)
/* Extract a 32 bit field from either size Shdr */
#define SH_E32E32(x, n) (ISELF64 ? SH_E64_32(x, n) : SH_E32_32(x, n))
/* Extract a 32 bit field from Elf32_Shdr or 64 bit field from Elf64_Shdr */
#define SH_E32E64(x, n) (ISELF64 ? SH_E64_64(x, n) : SH_E32_32(x, n))
#define SH_NAME(x) SH_E32E32(x, sh_name)
#define SH_TYPE(x) SH_E32E32(x, sh_type)
#define SH_FLAGS(x) SH_E32E64(x, sh_flags)
#define SH_ADDR(x) SH_E32E64(x, sh_addr)
#define SH_OFFSET(x) SH_E32E64(x, sh_offset)
#define SH_SIZE(x) SH_E32E64(x, sh_size)
#define SH_LINK(x) SH_E32E32(x, sh_link)
#define SH_INFO(x) SH_E32E32(x, sh_info)
#define SH_ADDRALIGN(x) SH_E32E64(x, sh_addralign)
#define SH_ENTSIZE(x) SH_E32E64(x, sh_entsize)
int
load_symtab(bfd *abfd, int fd, char **symtab, u_int32_t *symtabsize)
{
elf_ehdr ehdr;
Elf32_External_Shdr *s32hdr;
Elf64_External_Shdr *s64hdr;
void *shdr;
u_int32_t osymtabsize, sh_offset;
int elftype, e_shnum, i, sh_size;
off_t e_shoff;
if (lseek(fd, 0, SEEK_SET) < 0)
return (1);
if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
return (1);
/*
* Check that we are targetting an Elf binary.
*/
if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
ehdr.e_ident[EI_MAG3] != ELFMAG3)
return (1);
/*
* Determine Elf size and endianness.
*/
elftype = 0;
if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
elftype |= ELF_TYPE_64;
/*
* Elf exec header. Only need to allocate space for now,
* the header is copied into place at the end.
*/
*symtabsize = ISELF64 ? sizeof(Elf64_External_Ehdr)
: sizeof(Elf32_External_Ehdr);
*symtab = NULL;
/*
* Section headers. Allocate a temporary copy that will
* be copied into place at the end.
*/
sh_offset = osymtabsize = *symtabsize;
e_shnum = (ISELF64
? bfd_get_16(abfd, e64_hdr.e_shnum)
: bfd_get_16(abfd, e32_hdr.e_shnum));
sh_size = e_shnum * (ISELF64 ? sizeof(Elf64_External_Shdr)
: sizeof(Elf32_External_Shdr));
if ((shdr = malloc(sh_size)) == NULL)
return (1);
if (ISELF64)
s64hdr = shdr;
else
s32hdr = shdr;
*symtabsize += roundup(sh_size, ISELF64 ? 8 : 4);
e_shoff = (ISELF64
? bfd_get_64(abfd, e64_hdr.e_shoff)
: bfd_get_32(abfd, e32_hdr.e_shoff));
if (lseek(fd, e_shoff, SEEK_SET) < 0)
return (1);
if (read(fd, shdr, sh_size) != sh_size)
return (1);
for (i = 0; i < e_shnum; i++) {
if (SH_TYPE(i) == SHT_SYMTAB || SH_TYPE(i) == SHT_STRTAB) {
osymtabsize = *symtabsize;
*symtabsize += roundup(SH_SIZE(i), ISELF64 ? 8 : 4);
if ((*symtab = realloc(*symtab, *symtabsize)) == NULL)
return (1);
if (lseek(fd, SH_OFFSET(i), SEEK_SET) < 0)
return (1);
if (read(fd, *symtab + osymtabsize, SH_SIZE(i)) !=
SH_SIZE(i))
return (1);
if (ISELF64) {
bfd_put_64(abfd, osymtabsize,
s64hdr[i].sh_offset);
} else {
bfd_put_32(abfd, osymtabsize,
s32hdr[i].sh_offset);
}
}
}
/*
* Copy updated section headers.
*/
memcpy(*symtab + sh_offset, shdr, sh_size);
/*
* Update and copy the exec header.
*/
if (ISELF64) {
bfd_put_64(abfd, 0, e64_hdr.e_phoff);
bfd_put_64(abfd, sizeof(Elf64_External_Ehdr), e64_hdr.e_shoff);
bfd_put_16(abfd, 0, e64_hdr.e_phentsize);
bfd_put_16(abfd, 0, e64_hdr.e_phnum);
} else {
bfd_put_32(abfd, 0, e32_hdr.e_phoff);
bfd_put_32(abfd, sizeof(Elf32_External_Ehdr), e32_hdr.e_shoff);
bfd_put_16(abfd, 0, e32_hdr.e_phentsize);
bfd_put_16(abfd, 0, e32_hdr.e_phnum);
}
memcpy(*symtab, &ehdr, sizeof(ehdr));
return (0);
}
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