507 lines
12 KiB
C
507 lines
12 KiB
C
/* $NetBSD: elf.c,v 1.15 2003/10/21 02:31:08 fvdl Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 1998 Johan Danielsson <joda@pdc.kth.se>
|
|
* 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.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__RCSID("$NetBSD: elf.c,v 1.15 2003/10/21 02:31:08 fvdl Exp $");
|
|
|
|
#include <sys/param.h>
|
|
|
|
#if defined(__alpha__) || defined(__arch64__) || defined(__x86_64__)
|
|
#define ELFSIZE 64
|
|
#else
|
|
#define ELFSIZE 32
|
|
#endif
|
|
#include <sys/exec_elf.h>
|
|
#ifndef ELF_HDR_SIZE
|
|
#define ELF_HDR_SIZE sizeof(Elf_Ehdr)
|
|
#endif
|
|
#include <sys/lkm.h>
|
|
|
|
#include <err.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <fcntl.h>
|
|
|
|
#include "modload.h"
|
|
|
|
char *strtab;
|
|
|
|
static void
|
|
read_section_header(int fd, Elf_Ehdr *ehdr, int num, Elf_Shdr *shdr)
|
|
{
|
|
|
|
if (lseek(fd, ehdr->e_shoff + num * ehdr->e_shentsize, SEEK_SET) < 0)
|
|
err(1, "lseek");
|
|
if (read(fd, shdr, sizeof(*shdr)) != sizeof(*shdr))
|
|
err(1, "read");
|
|
}
|
|
|
|
struct elf_section {
|
|
char *name; /* name of section; points into string table */
|
|
unsigned long type; /* type of section */
|
|
void *addr; /* load address of section */
|
|
off_t offset; /* offset in file */
|
|
size_t size; /* size of section */
|
|
size_t align;
|
|
struct elf_section *next;
|
|
};
|
|
|
|
/* adds the section `s' at the correct (sorted by address) place in
|
|
the list pointed to by head; *head may be NULL */
|
|
static void
|
|
add_section(struct elf_section **head, struct elf_section *s)
|
|
{
|
|
struct elf_section *p, **q;
|
|
q = head;
|
|
p = *head;
|
|
|
|
while (1) {
|
|
if (p == NULL || p->addr > s->addr) {
|
|
s->next = p;
|
|
*q = s;
|
|
return;
|
|
}
|
|
q = &p->next;
|
|
p = p->next;
|
|
}
|
|
}
|
|
|
|
/* make a linked list of all sections containing ALLOCatable data */
|
|
static void
|
|
read_sections(int fd, Elf_Ehdr *ehdr, char *shstrtab, struct elf_section **head)
|
|
{
|
|
int i;
|
|
Elf_Shdr shdr;
|
|
*head = NULL;
|
|
/* scan through section headers */
|
|
for (i = 0; i < ehdr->e_shnum; i++) {
|
|
struct elf_section *s;
|
|
read_section_header(fd, ehdr, i, &shdr);
|
|
if (shdr.sh_size == 0)
|
|
continue;
|
|
if (((shdr.sh_flags & SHF_ALLOC) == 0)
|
|
&& (shdr.sh_type != SHT_STRTAB)
|
|
&& (shdr.sh_type != SHT_SYMTAB)
|
|
&& (shdr.sh_type != SHT_DYNSYM)) {
|
|
/* skip non-ALLOC sections */
|
|
continue;
|
|
}
|
|
s = malloc(sizeof(*s));
|
|
if (s == NULL)
|
|
errx(1, "failed to allocate %lu bytes", (u_long)sizeof(*s));
|
|
s->name = shstrtab + shdr.sh_name;
|
|
s->type = shdr.sh_type;
|
|
s->addr = (void *)shdr.sh_addr;
|
|
s->offset = shdr.sh_offset;
|
|
s->size = shdr.sh_size;
|
|
s->align = shdr.sh_addralign;
|
|
add_section(head, s);
|
|
}
|
|
}
|
|
|
|
/* get the symbol table sections and free the rest of them */
|
|
static void
|
|
get_symtab(struct elf_section **symtab)
|
|
{
|
|
struct elf_section *head, *cur, *prev;
|
|
|
|
head = NULL;
|
|
prev = NULL;
|
|
cur = *symtab;
|
|
while (cur) {
|
|
if ((cur->type == SHT_SYMTAB) || (cur->type == SHT_DYNSYM)) {
|
|
if (head == NULL) {
|
|
head = cur;
|
|
}
|
|
if (prev != NULL) {
|
|
prev->next = cur;
|
|
}
|
|
prev = cur;
|
|
cur = cur->next;
|
|
} else {
|
|
struct elf_section *p = cur;
|
|
cur = cur->next;
|
|
p->next = NULL;
|
|
free(p);
|
|
}
|
|
}
|
|
if (prev) {
|
|
prev->next = NULL;
|
|
}
|
|
*symtab = head;
|
|
}
|
|
|
|
/* free a list of section headers */
|
|
static void
|
|
free_sections(struct elf_section *head)
|
|
{
|
|
|
|
while (head) {
|
|
struct elf_section *p = head;
|
|
head = head->next;
|
|
free(p);
|
|
}
|
|
}
|
|
|
|
/* read section header's string table */
|
|
static char *
|
|
read_shstring_table(int fd, Elf_Ehdr *ehdr)
|
|
{
|
|
Elf_Shdr shdr;
|
|
char *shstrtab;
|
|
read_section_header(fd, ehdr, ehdr->e_shstrndx, &shdr);
|
|
shstrtab = malloc(shdr.sh_size);
|
|
if (shstrtab == NULL)
|
|
errx(1, "failed to allocate %lu bytes", (u_long)shdr.sh_size);
|
|
if (lseek(fd, shdr.sh_offset, SEEK_SET) < 0)
|
|
err(1, "lseek");
|
|
if (read(fd, shstrtab, shdr.sh_size) != shdr.sh_size)
|
|
err(1, "read");
|
|
return shstrtab;
|
|
}
|
|
|
|
/* read string table */
|
|
static char *
|
|
read_string_table(int fd, struct elf_section *head, int *strtablen)
|
|
{
|
|
char *string_table=NULL;
|
|
|
|
while (head) {
|
|
if ((strcmp(head->name, ".strtab") == 0 )
|
|
&& (head->type == SHT_STRTAB)) {
|
|
string_table = malloc(head->size);
|
|
if (string_table == NULL)
|
|
errx(1, "failed to allocate %lu bytes",
|
|
(u_long)head->size);
|
|
if (lseek(fd, head->offset, SEEK_SET) < 0)
|
|
err(1, "lseek");
|
|
if (read(fd, string_table, head->size) != head->size)
|
|
err(1, "read");
|
|
*strtablen = head->size;
|
|
break;
|
|
} else {
|
|
head = head->next;
|
|
}
|
|
}
|
|
return string_table;
|
|
}
|
|
|
|
static int
|
|
read_elf_header(int fd, Elf_Ehdr *ehdr)
|
|
{
|
|
ssize_t n;
|
|
|
|
n = read(fd, ehdr, sizeof(*ehdr));
|
|
if (n < 0)
|
|
err(1, "failed reading %lu bytes", (u_long)sizeof(*ehdr));
|
|
if (n != sizeof(*ehdr)) {
|
|
if (debug)
|
|
warnx("failed to read %lu bytes", (u_long)sizeof(*ehdr));
|
|
return -1;
|
|
}
|
|
if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0 ||
|
|
ehdr->e_ident[EI_CLASS] != ELFCLASS)
|
|
errx(4, "not in ELF%u format", ELFSIZE);
|
|
if (ehdr->e_ehsize != ELF_HDR_SIZE)
|
|
errx(4, "file has ELF%u identity, but wrong header size",
|
|
ELFSIZE);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* offset of data segment; this is horrible, but keeps the size of the
|
|
module to a minimum */
|
|
static ssize_t data_offset;
|
|
|
|
/* return size needed by the module */
|
|
int
|
|
elf_mod_sizes(int fd,
|
|
size_t *modsize,
|
|
int *strtablen,
|
|
struct lmc_resrv *resrvp,
|
|
struct stat *sp)
|
|
{
|
|
Elf_Ehdr ehdr;
|
|
ssize_t off = 0;
|
|
size_t data_hole = 0;
|
|
char *shstrtab, *strtab;
|
|
struct elf_section *head, *s;
|
|
|
|
if (read_elf_header(fd, &ehdr) < 0)
|
|
return -1;
|
|
shstrtab = read_shstring_table(fd, &ehdr);
|
|
read_sections(fd, &ehdr, shstrtab, &head);
|
|
|
|
for (s = head; s; s = s->next) {
|
|
if ((s->type == SHT_STRTAB) && (s->type == SHT_SYMTAB)
|
|
&& (s->type == SHT_DYNSYM)) {
|
|
continue;
|
|
}
|
|
if (debug)
|
|
fprintf(stderr,
|
|
"%s: addr = %p size = %#lx align = %#lx\n",
|
|
s->name, s->addr, (u_long)s->size, (u_long)s->align);
|
|
/* XXX try to get rid of the hole before the data
|
|
section that GNU-ld likes to put there */
|
|
if (strcmp(s->name, ".data") == 0 && s->addr > (void *)off) {
|
|
#define ROUND(V, S) (((V) + (S) - 1) & ~((S) - 1))
|
|
data_offset = ROUND(off, s->align);
|
|
if (debug)
|
|
fprintf(stderr, ".data section forced to "
|
|
"offset %p (was %p)\n",
|
|
(void *)data_offset,
|
|
s->addr);
|
|
/* later remove size of compressed hole from off */
|
|
data_hole = (ssize_t)s->addr - data_offset;
|
|
}
|
|
off = (ssize_t)s->addr + s->size;
|
|
}
|
|
off -= data_hole;
|
|
|
|
/* XXX round to pagesize? */
|
|
*modsize = ROUND(off, sysconf(_SC_PAGESIZE));
|
|
free(shstrtab);
|
|
|
|
/* get string table length */
|
|
strtab = read_string_table(fd, head, strtablen);
|
|
free(strtab);
|
|
|
|
/* get symbol table sections */
|
|
resrvp->sym_symsize = 0;
|
|
if (symtab) {
|
|
struct elf_section *st;
|
|
|
|
get_symtab(&head);
|
|
for(st = head; st; st = st->next)
|
|
resrvp->sym_symsize += st->size;
|
|
resrvp->sym_size = resrvp->sym_symsize + *strtablen;
|
|
} else
|
|
resrvp->sym_size = 0;
|
|
free_sections(head);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Expected linker options:
|
|
*
|
|
* -R executable to link against
|
|
* -e entry point
|
|
* -o output file
|
|
* -Ttext address to link text segment to in hex (assumes it's
|
|
* a page boundary)
|
|
* -Tdata address to link data segment to in hex
|
|
* <target> object file
|
|
* -T ldscript linker script (on some archs)
|
|
*/
|
|
|
|
#define LINKCMD "ld -R %s -e %s -o %s -Ttext %p %s"
|
|
#define LINKCMD2 "ld -R %s -e %s -o %s -Ttext %p -Tdata %p %s"
|
|
#define LINKSCRIPTCMD "ld -T %s -R %s -e %s -o %s -Ttext %p %s"
|
|
#define LINKSCRIPTCMD2 "ld -T %s -R %s -e %s -o %s -Ttext %p -Tdata %p %s"
|
|
|
|
/* make a link command; XXX if data_offset above is non-zero, force
|
|
data address to be at start of text + offset */
|
|
void
|
|
elf_linkcmd(char *buf,
|
|
size_t len,
|
|
const char *kernel,
|
|
const char *entry,
|
|
const char *outfile,
|
|
const void *address,
|
|
const char *object,
|
|
const char *ldscript)
|
|
{
|
|
ssize_t n;
|
|
|
|
if (ldscript == NULL) {
|
|
if (data_offset == 0)
|
|
n = snprintf(buf, len, LINKCMD, kernel, entry,
|
|
outfile, address, object);
|
|
else
|
|
n = snprintf(buf, len, LINKCMD2, kernel, entry,
|
|
outfile, address,
|
|
(const char *)address + data_offset,
|
|
object);
|
|
} else {
|
|
if (data_offset == 0)
|
|
n = snprintf(buf, len, LINKSCRIPTCMD, ldscript, kernel,
|
|
entry, outfile, address, object);
|
|
else
|
|
n = snprintf(buf, len, LINKSCRIPTCMD2, ldscript, kernel,
|
|
entry, outfile, address,
|
|
(const char *)address + data_offset,
|
|
object);
|
|
}
|
|
|
|
if (n >= len)
|
|
errx(1, "link command longer than %lu bytes", (u_long)len);
|
|
}
|
|
|
|
/* load a pre-linked module; returns entry point */
|
|
void *
|
|
elf_mod_load(int fd)
|
|
{
|
|
Elf_Ehdr ehdr;
|
|
size_t zero_size = 0;
|
|
size_t b;
|
|
ssize_t n;
|
|
char *shstrtab;
|
|
struct elf_section *head, *s;
|
|
char buf[10 * BUFSIZ];
|
|
void *addr = NULL;
|
|
|
|
if (read_elf_header(fd, &ehdr) < 0)
|
|
return NULL;
|
|
|
|
shstrtab = read_shstring_table(fd, &ehdr);
|
|
read_sections(fd, &ehdr, shstrtab, &head);
|
|
|
|
for (s = head; s; s = s->next) {
|
|
if ((s->type != SHT_STRTAB) && (s->type != SHT_SYMTAB)
|
|
&& (s->type != SHT_DYNSYM)) {
|
|
if (debug)
|
|
fprintf(stderr, "loading `%s': addr = %p, "
|
|
"size = %#lx\n",
|
|
s->name, s->addr, (u_long)s->size);
|
|
if (s->type == SHT_NOBITS) {
|
|
/* skip some space */
|
|
zero_size += s->size;
|
|
} else {
|
|
if (addr != NULL) {
|
|
/* if there is a gap in the prelinked
|
|
module, transfer some empty
|
|
space... */
|
|
zero_size += (char *)s->addr
|
|
- (char *)addr;
|
|
}
|
|
if (zero_size) {
|
|
loadspace(zero_size);
|
|
zero_size = 0;
|
|
}
|
|
b = s->size;
|
|
if (lseek(fd, s->offset, SEEK_SET) == -1)
|
|
err(1, "lseek");
|
|
while (b) {
|
|
n = read(fd, buf, MIN(b, sizeof(buf)));
|
|
if (n == 0)
|
|
errx(1, "unexpected EOF");
|
|
if (n < 0)
|
|
err(1, "read");
|
|
loadbuf(buf, n);
|
|
b -= n;
|
|
}
|
|
addr = (char *)s->addr + s->size;
|
|
}
|
|
}
|
|
}
|
|
if (zero_size)
|
|
loadspace(zero_size);
|
|
|
|
free_sections(head);
|
|
free(shstrtab);
|
|
return (void *)ehdr.e_entry;
|
|
}
|
|
|
|
void
|
|
elf_mod_symload(int strtablen)
|
|
{
|
|
Elf_Ehdr ehdr;
|
|
char *shstrtab;
|
|
struct elf_section *head, *s;
|
|
char *symbuf, *strbuf;
|
|
|
|
/*
|
|
* Seek to the text offset to start loading...
|
|
*/
|
|
if (lseek(modfd, 0, SEEK_SET) == -1)
|
|
err(12, "lseek");
|
|
if (read_elf_header(modfd, &ehdr) < 0)
|
|
return;
|
|
|
|
shstrtab = read_shstring_table(modfd, &ehdr);
|
|
read_sections(modfd, &ehdr, shstrtab, &head);
|
|
|
|
for (s = head; s; s = s->next) {
|
|
struct elf_section *p = s;
|
|
|
|
if ((p->type == SHT_SYMTAB) || (p->type == SHT_DYNSYM)) {
|
|
if (debug)
|
|
fprintf(stderr, "loading `%s': addr = %p, "
|
|
"size = %#lx\n",
|
|
s->name, s->addr, (u_long)s->size);
|
|
/*
|
|
* Seek to the file offset to start loading it...
|
|
*/
|
|
if (lseek(modfd, p->offset, SEEK_SET) == -1)
|
|
err(12, "lseek");
|
|
symbuf = malloc(p->size);
|
|
if (symbuf == 0)
|
|
err(13, "malloc");
|
|
if (read(modfd, symbuf, p->size) != p->size)
|
|
err(14, "read");
|
|
|
|
loadsym(symbuf, p->size);
|
|
free(symbuf);
|
|
}
|
|
}
|
|
|
|
for (s = head; s; s = s->next) {
|
|
struct elf_section *p = s;
|
|
|
|
if ((p->type == SHT_STRTAB)
|
|
&& (strcmp(p->name, ".strtab") == 0 )) {
|
|
if (debug)
|
|
fprintf(stderr, "loading `%s': addr = %p, "
|
|
"size = %#lx\n",
|
|
s->name, s->addr, (u_long)s->size);
|
|
/*
|
|
* Seek to the file offset to start loading it...
|
|
*/
|
|
if (lseek(modfd, p->offset, SEEK_SET) == -1)
|
|
err(12, "lseek");
|
|
strbuf = malloc(p->size);
|
|
if (strbuf == 0)
|
|
err(13, "malloc");
|
|
if (read(modfd, strbuf, p->size) != p->size)
|
|
err(14, "read");
|
|
|
|
loadsym(strbuf, p->size);
|
|
free(strbuf);
|
|
}
|
|
}
|
|
|
|
free(shstrtab);
|
|
free_sections(head);
|
|
return;
|
|
}
|