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freebsd/usr.sbin/kldxref/ef_obj.c
Ian Dowse 9dba198b0e Explicitly pass in the relocation base and data offset into ef_reloc()
rather than relying on a trick that happens to work for the current
relocation schemes. Also add some comments and improve variable
naming.
2004-08-28 19:31:10 +00:00

607 lines
15 KiB
C

/*
* Copyright (c) 2000, Boris Popov
* Copyright (c) 1998-2000 Doug Rabson
* Copyright (c) 2004 Peter Wemm
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Boris Popov.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/param.h>
#include <sys/linker.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <machine/elf.h>
#define FREEBSD_ELF
#include <link.h>
#include <err.h>
#include "ef.h"
typedef struct {
void *addr;
Elf_Off size;
int flags;
int sec; /* Original section */
char *name;
} Elf_progent;
typedef struct {
Elf_Rel *rel;
int nrel;
int sec;
} Elf_relent;
typedef struct {
Elf_Rela *rela;
int nrela;
int sec;
} Elf_relaent;
struct ef_file {
char *ef_name;
int ef_fd;
Elf_Ehdr ef_hdr;
struct elf_file *ef_efile;
caddr_t address;
Elf_Off size;
Elf_Shdr *e_shdr;
Elf_progent *progtab;
int nprogtab;
Elf_relaent *relatab;
int nrela;
Elf_relent *reltab;
int nrel;
Elf_Sym *ddbsymtab; /* The symbol table we are using */
long ddbsymcnt; /* Number of symbols */
caddr_t ddbstrtab; /* String table */
long ddbstrcnt; /* number of bytes in string table */
caddr_t shstrtab; /* Section name string table */
long shstrcnt; /* number of bytes in string table */
int ef_verbose;
};
static int ef_obj_get_type(elf_file_t ef);
static int ef_obj_close(elf_file_t ef);
static int ef_obj_read(elf_file_t ef, Elf_Off offset, size_t len, void* dest);
static int ef_obj_read_entry(elf_file_t ef, Elf_Off offset, size_t len,
void **ptr);
static int ef_obj_seg_read(elf_file_t ef, Elf_Off offset, size_t len,
void *dest);
static int ef_obj_seg_read_rel(elf_file_t ef, Elf_Off offset, size_t len,
void *dest);
static int ef_obj_seg_read_entry(elf_file_t ef, Elf_Off offset, size_t len,
void **ptr);
static int ef_obj_seg_read_entry_rel(elf_file_t ef, Elf_Off offset, size_t len,
void **ptr);
static Elf_Addr ef_obj_symaddr(elf_file_t ef, Elf_Word symidx);
static int ef_obj_lookup_set(elf_file_t ef, const char *name, long *startp,
long *stopp, long *countp);
static int ef_obj_lookup_symbol(elf_file_t ef, const char* name, Elf_Sym** sym);
static struct elf_file_ops ef_obj_file_ops = {
ef_obj_get_type,
ef_obj_close,
ef_obj_read,
ef_obj_read_entry,
ef_obj_seg_read,
ef_obj_seg_read_rel,
ef_obj_seg_read_entry,
ef_obj_seg_read_entry_rel,
ef_obj_symaddr,
ef_obj_lookup_set,
ef_obj_lookup_symbol
};
static int
ef_obj_get_type(elf_file_t ef)
{
return (EFT_KLD);
}
static int
ef_obj_lookup_symbol(elf_file_t ef, const char* name, Elf_Sym** sym)
{
Elf_Sym *symp;
const char *strp;
int i;
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
strp = ef->ddbstrtab + symp->st_name;
if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
*sym = symp;
return 0;
}
}
return ENOENT;
}
static int
ef_obj_lookup_set(elf_file_t ef, const char *name, long *startp, long *stopp,
long *countp)
{
int i;
for (i = 0; i < ef->nprogtab; i++) {
if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
strcmp(ef->progtab[i].name + 4, name) == 0) {
*startp = (char *)ef->progtab[i].addr - ef->address;
*stopp = (char *)ef->progtab[i].addr +
ef->progtab[i].size - ef->address;
*countp = (*stopp - *startp) / sizeof(void *);
return (0);
}
}
return (ESRCH);
}
static Elf_Addr
ef_obj_symaddr(elf_file_t ef, Elf_Word symidx)
{
const Elf_Sym *sym;
if (symidx >= ef->ddbsymcnt)
return (0);
sym = ef->ddbsymtab + symidx;
if (sym->st_shndx != SHN_UNDEF)
return (sym->st_value - (Elf_Addr)ef->address);
return (0);
}
static int
ef_obj_read(elf_file_t ef, Elf_Off offset, size_t len, void *dest)
{
ssize_t r;
if (offset != (Elf_Off)-1) {
if (lseek(ef->ef_fd, offset, SEEK_SET) == -1)
return EIO;
}
r = read(ef->ef_fd, dest, len);
if (r != -1 && (size_t)r == len)
return 0;
else
return EIO;
}
static int
ef_obj_read_entry(elf_file_t ef, Elf_Off offset, size_t len, void **ptr)
{
int error;
*ptr = malloc(len);
if (*ptr == NULL)
return ENOMEM;
error = ef_obj_read(ef, offset, len, *ptr);
if (error)
free(*ptr);
return error;
}
static int
ef_obj_seg_read(elf_file_t ef, Elf_Off offset, size_t len, void *dest)
{
if (offset + len > ef->size) {
if (ef->ef_verbose)
warnx("ef_seg_read_rel(%s): bad offset/len (%lx:%ld)",
ef->ef_name, (long)offset, (long)len);
return (EFAULT);
}
bcopy(ef->address + offset, dest, len);
return (0);
}
static int
ef_obj_seg_read_rel(elf_file_t ef, Elf_Off offset, size_t len, void *dest)
{
char *memaddr;
Elf_Rel *r;
Elf_Rela *a;
Elf_Off secbase, dataoff;
int error, i, sec;
if (offset + len > ef->size) {
if (ef->ef_verbose)
warnx("ef_seg_read_rel(%s): bad offset/len (%lx:%ld)",
ef->ef_name, (long)offset, (long)len);
return (EFAULT);
}
bcopy(ef->address + offset, dest, len);
/* Find out which section contains the data. */
memaddr = ef->address + offset;
sec = -1;
secbase = dataoff = 0;
for (i = 0; i < ef->nprogtab; i++) {
if (ef->progtab[i].addr == NULL)
continue;
if (memaddr < (char *)ef->progtab[i].addr || memaddr + len >
(char *)ef->progtab[i].addr + ef->progtab[i].size)
continue;
sec = ef->progtab[i].sec;
/* We relocate to address 0. */
secbase = (char *)ef->progtab[i].addr - ef->address;
dataoff = memaddr - ef->address;
break;
}
if (sec == -1)
return (EFAULT);
/* Now do the relocations. */
for (i = 0; i < ef->nrel; i++) {
if (ef->reltab[i].sec != sec)
continue;
for (r = ef->reltab[i].rel;
r < &ef->reltab[i].rel[ef->reltab[i].nrel]; r++) {
error = ef_reloc(ef->ef_efile, r, EF_RELOC_REL, secbase,
dataoff, len, dest);
if (error != 0)
return (error);
}
}
for (i = 0; i < ef->nrela; i++) {
if (ef->relatab[i].sec != sec)
continue;
for (a = ef->relatab[i].rela;
a < &ef->relatab[i].rela[ef->relatab[i].nrela]; a++) {
error = ef_reloc(ef->ef_efile, a, EF_RELOC_RELA,
secbase, dataoff, len, dest);
if (error != 0)
return (error);
}
}
return (0);
}
static int
ef_obj_seg_read_entry(elf_file_t ef, Elf_Off offset, size_t len, void **ptr)
{
int error;
*ptr = malloc(len);
if (*ptr == NULL)
return ENOMEM;
error = ef_obj_seg_read(ef, offset, len, *ptr);
if (error)
free(*ptr);
return error;
}
static int
ef_obj_seg_read_entry_rel(elf_file_t ef, Elf_Off offset, size_t len,
void **ptr)
{
int error;
*ptr = malloc(len);
if (*ptr == NULL)
return ENOMEM;
error = ef_obj_seg_read_rel(ef, offset, len, *ptr);
if (error)
free(*ptr);
return error;
}
int
ef_obj_open(const char *filename, struct elf_file *efile, int verbose)
{
elf_file_t ef;
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
Elf_Sym *es;
char *mapbase;
void *vtmp;
size_t mapsize;
int alignmask, error, fd, pb, ra, res, rl;
int i, j, nbytes, nsym, shstrindex, symstrindex, symtabindex;
if (filename == NULL)
return EFTYPE;
if ((fd = open(filename, O_RDONLY)) == -1)
return errno;
ef = malloc(sizeof(*ef));
if (ef == NULL) {
close(fd);
return (ENOMEM);
}
efile->ef_ef = ef;
efile->ef_ops = &ef_obj_file_ops;
bzero(ef, sizeof(*ef));
ef->ef_verbose = verbose;
ef->ef_fd = fd;
ef->ef_name = strdup(filename);
ef->ef_efile = efile;
hdr = (Elf_Ehdr *)&ef->ef_hdr;
res = read(fd, hdr, sizeof(*hdr));
error = EFTYPE;
if (res != sizeof(*hdr))
goto out;
if (!IS_ELF(*hdr))
goto out;
if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_version != EV_CURRENT || hdr->e_machine != ELF_TARG_MACH ||
hdr->e_type != ET_REL)
goto out;
nbytes = hdr->e_shnum * hdr->e_shentsize;
if (nbytes == 0 || hdr->e_shoff == 0 ||
hdr->e_shentsize != sizeof(Elf_Shdr))
goto out;
if (ef_obj_read_entry(ef, hdr->e_shoff, nbytes, &vtmp) != 0) {
printf("ef_read_entry failed\n");
goto out;
}
ef->e_shdr = shdr = vtmp;
/* Scan the section header for information and table sizing. */
nsym = 0;
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
ef->nprogtab++;
break;
case SHT_SYMTAB:
nsym++;
symtabindex = i;
symstrindex = shdr[i].sh_link;
break;
case SHT_REL:
ef->nrel++;
break;
case SHT_RELA:
ef->nrela++;
break;
case SHT_STRTAB:
break;
}
}
if (ef->nprogtab == 0) {
warnx("%s: file has no contents", filename);
goto out;
}
if (nsym != 1) {
warnx("%s: file has no valid symbol table", filename);
goto out;
}
if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
shdr[symstrindex].sh_type != SHT_STRTAB) {
warnx("%s: file has invalid symbol strings", filename);
goto out;
}
/* Allocate space for tracking the load chunks */
if (ef->nprogtab != 0)
ef->progtab = calloc(ef->nprogtab, sizeof(*ef->progtab));
if (ef->nrel != 0)
ef->reltab = calloc(ef->nrel, sizeof(*ef->reltab));
if (ef->nrela != 0)
ef->relatab = calloc(ef->nrela, sizeof(*ef->relatab));
if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
(ef->nrel != 0 && ef->reltab == NULL) ||
(ef->nrela != 0 && ef->relatab == NULL)) {
printf("malloc failed\n");
error = ENOMEM;
goto out;
}
ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
if (ef_obj_read_entry(ef, shdr[symtabindex].sh_offset,
shdr[symtabindex].sh_size, (void**)&ef->ddbsymtab) != 0) {
printf("ef_read_entry failed\n");
goto out;
}
ef->ddbstrcnt = shdr[symstrindex].sh_size;
if (ef_obj_read_entry(ef, shdr[symstrindex].sh_offset,
shdr[symstrindex].sh_size, (void**)&ef->ddbstrtab) != 0) {
printf("ef_read_entry failed\n");
goto out;
}
/* Do we have a string table for the section names? */
shstrindex = -1;
if (hdr->e_shstrndx != 0 &&
shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
shstrindex = hdr->e_shstrndx;
ef->shstrcnt = shdr[shstrindex].sh_size;
if (ef_obj_read_entry(ef, shdr[shstrindex].sh_offset,
shdr[shstrindex].sh_size, (void**)&ef->shstrtab) != 0) {
printf("ef_read_entry failed\n");
goto out;
}
}
/* Size up code/data(progbits) and bss(nobits). */
alignmask = 0;
mapsize = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
alignmask = shdr[i].sh_addralign - 1;
mapsize += alignmask;
mapsize &= ~alignmask;
mapsize += shdr[i].sh_size;
break;
}
}
/* We know how much space we need for the text/data/bss/etc. */
ef->address = malloc(mapsize);
ef->size = mapsize;
if (ef->address == NULL) {
printf("malloc failed\n");
goto out;
}
mapbase = ef->address;
/*
* Now load code/data(progbits), zero bss(nobits), allocate
* space for and load relocs
*/
pb = 0;
rl = 0;
ra = 0;
alignmask = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
alignmask = shdr[i].sh_addralign - 1;
mapbase += alignmask;
mapbase = (char *)((uintptr_t)mapbase & ~alignmask);
ef->progtab[pb].addr = (void *)(uintptr_t)mapbase;
if (shdr[i].sh_type == SHT_PROGBITS) {
ef->progtab[pb].name = "<<PROGBITS>>";
if (ef_obj_read(ef, shdr[i].sh_offset,
shdr[i].sh_size,
ef->progtab[pb].addr) != 0) {
printf("failed to read progbits\n");
goto out;
}
} else {
ef->progtab[pb].name = "<<NOBITS>>";
bzero(ef->progtab[pb].addr, shdr[i].sh_size);
}
ef->progtab[pb].size = shdr[i].sh_size;
ef->progtab[pb].sec = i;
if (ef->shstrtab && shdr[i].sh_name != 0)
ef->progtab[pb].name =
ef->shstrtab + shdr[i].sh_name;
/* Update all symbol values with the offset. */
for (j = 0; j < ef->ddbsymcnt; j++) {
es = &ef->ddbsymtab[j];
if (es->st_shndx != i)
continue;
es->st_value += (Elf_Addr)ef->progtab[pb].addr;
}
mapbase += shdr[i].sh_size;
pb++;
break;
case SHT_REL:
ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
ef->reltab[rl].sec = shdr[i].sh_info;
if (ef_obj_read_entry(ef, shdr[i].sh_offset,
shdr[i].sh_size, (void**)&ef->reltab[rl].rel) !=
0) {
printf("ef_read_entry failed\n");
goto out;
}
rl++;
break;
case SHT_RELA:
ef->relatab[ra].nrela =
shdr[i].sh_size / sizeof(Elf_Rela);
ef->relatab[ra].sec = shdr[i].sh_info;
if (ef_obj_read_entry(ef, shdr[i].sh_offset,
shdr[i].sh_size, (void**)&ef->relatab[ra].rela) !=
0) {
printf("ef_read_entry failed\n");
goto out;
}
ra++;
break;
}
}
error = 0;
out:
if (error)
ef_obj_close(ef);
return error;
}
static int
ef_obj_close(elf_file_t ef)
{
int i;
close(ef->ef_fd);
if (ef->ef_name)
free(ef->ef_name);
if (ef->e_shdr != NULL)
free(ef->e_shdr);
if (ef->size != 0)
free(ef->address);
if (ef->nprogtab != 0)
free(ef->progtab);
if (ef->nrel != 0) {
for (i = 0; i < ef->nrel; i++)
if (ef->reltab[i].rel != NULL)
free(ef->reltab[i].rel);
free(ef->reltab);
}
if (ef->nrela != 0) {
for (i = 0; i < ef->nrela; i++)
if (ef->relatab[i].rela != NULL)
free(ef->relatab[i].rela);
free(ef->relatab);
}
if (ef->ddbsymtab != NULL)
free(ef->ddbsymtab);
if (ef->ddbstrtab != NULL)
free(ef->ddbstrtab);
if (ef->shstrtab != NULL)
free(ef->shstrtab);
ef->ef_efile->ef_ops = NULL;
ef->ef_efile->ef_ef = NULL;
free(ef);
return 0;
}