FreeBSD-5.3/sys/boot/common/load_elf_obj.c
/*-
* Copyright (c) 2004 Ian Dowse <iedowse@freebsd.org>
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* Copyright (c) 1998 Peter Wemm <peter@freebsd.org>
* 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.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/boot/common/load_elf_obj.c,v 1.1.2.1 2004/09/03 19:25:40 iedowse Exp $");
#include <sys/param.h>
#include <sys/exec.h>
#include <sys/linker.h>
#include <sys/module.h>
#include <inttypes.h>
#include <string.h>
#include <machine/elf.h>
#include <stand.h>
#define FREEBSD_ELF
#include <link.h>
#include "bootstrap.h"
#define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l)
#if defined(__i386__) && __ELF_WORD_SIZE == 64
#undef ELF_TARG_CLASS
#undef ELF_TARG_MACH
#define ELF_TARG_CLASS ELFCLASS64
#define ELF_TARG_MACH EM_X86_64
#endif
typedef struct elf_file {
Elf_Ehdr hdr;
Elf_Shdr *e_shdr;
int symtabindex; /* Index of symbol table */
int shstrindex; /* Index of section name string table */
int fd;
vm_offset_t off;
} *elf_file_t;
static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef,
u_int64_t loadaddr);
static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef,
const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp);
static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
Elf_Addr p, void *val, size_t len);
static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp,
elf_file_t ef);
static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Word symidx);
const char *__elfN(obj_kerneltype) = "elf kernel";
const char *__elfN(obj_moduletype) = "elf obj module";
/*
* Attempt to load the file (file) as an ELF module. It will be stored at
* (dest), and a pointer to a module structure describing the loaded object
* will be saved in (result).
*/
int
__elfN(obj_loadfile)(char *filename, u_int64_t dest,
struct preloaded_file **result)
{
struct preloaded_file *fp, *kfp;
struct elf_file ef;
Elf_Ehdr *hdr;
int err;
ssize_t bytes_read;
fp = NULL;
bzero(&ef, sizeof(struct elf_file));
/*
* Open the image, read and validate the ELF header
*/
if (filename == NULL) /* can't handle nameless */
return(EFTYPE);
if ((ef.fd = open(filename, O_RDONLY)) == -1)
return(errno);
hdr = &ef.hdr;
bytes_read = read(ef.fd, hdr, sizeof(*hdr));
if (bytes_read != sizeof(*hdr)) {
err = EFTYPE; /* could be EIO, but may be small file */
goto oerr;
}
/* Is it ELF? */
if (!IS_ELF(*hdr)) {
err = EFTYPE;
goto oerr;
}
if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */
hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */
hdr->e_version != EV_CURRENT ||
hdr->e_machine != ELF_TARG_MACH || /* Machine ? */
hdr->e_type != ET_REL) {
err = EFTYPE;
goto oerr;
}
if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 ||
hdr->e_shentsize != sizeof(Elf_Shdr)) {
err = EFTYPE;
goto oerr;
}
kfp = file_findfile(NULL, NULL);
if (kfp == NULL) {
printf("elf" __XSTRING(__ELF_WORD_SIZE)
"_obj_loadfile: can't load module before kernel\n");
err = EPERM;
goto oerr;
}
if (strcmp(__elfN(obj_kerneltype), kfp->f_type)) {
printf("elf" __XSTRING(__ELF_WORD_SIZE)
"_obj_loadfile: can't load module with kernel type '%s'\n",
kfp->f_type);
err = EPERM;
goto oerr;
}
/* Page-align the load address */
dest = roundup(dest, PAGE_SIZE);
/*
* Ok, we think we should handle this.
*/
fp = file_alloc();
if (fp == NULL) {
printf("elf" __XSTRING(__ELF_WORD_SIZE)
"_obj_loadfile: cannot allocate module info\n");
err = EPERM;
goto out;
}
fp->f_name = strdup(filename);
fp->f_type = strdup(__elfN(obj_moduletype));
printf("%s ", filename);
fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
if (fp->f_size == 0 || fp->f_addr == 0)
goto ioerr;
/* save exec header as metadata */
file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr);
/* Load OK, return module pointer */
*result = (struct preloaded_file *)fp;
err = 0;
goto out;
ioerr:
err = EIO;
oerr:
file_discard(fp);
out:
close(ef.fd);
if (ef.e_shdr != NULL)
free(ef.e_shdr);
return(err);
}
/*
* With the file (fd) open on the image, and (ehdr) containing
* the Elf header, load the image at (off)
*/
static int
__elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
{
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
vm_offset_t firstaddr, lastaddr;
int i, nsym, res, ret, shdrbytes, symstrindex;
ret = 0;
firstaddr = lastaddr = (vm_offset_t)off;
hdr = &ef->hdr;
ef->off = (vm_offset_t)off;
/* Read in the section headers. */
shdrbytes = hdr->e_shnum * hdr->e_shentsize;
shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes);
if (shdr == NULL) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
"_obj_loadimage: read section headers failed\n");
goto out;
}
ef->e_shdr = shdr;
/*
* Decide where to load everything, but don't read it yet.
* We store the load address as a non-zero sh_addr value.
* Start with the code/data and bss.
*/
for (i = 0; i < hdr->e_shnum; i++)
shdr[i].sh_addr = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
shdr[i].sh_addr = (Elf_Addr)lastaddr;
lastaddr += shdr[i].sh_size;
break;
}
}
/* Symbols. */
nsym = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_SYMTAB:
nsym++;
ef->symtabindex = i;
shdr[i].sh_addr = (Elf_Addr)lastaddr;
lastaddr += shdr[i].sh_size;
break;
}
}
if (nsym != 1) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
"_obj_loadimage: file has no valid symbol table\n");
goto out;
}
lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
lastaddr += shdr[ef->symtabindex].sh_size;
symstrindex = shdr[ef->symtabindex].sh_link;
if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
shdr[symstrindex].sh_type != SHT_STRTAB) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
"_obj_loadimage: file has invalid symbol strings\n");
goto out;
}
lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
lastaddr += shdr[symstrindex].sh_size;
/* Section names. */
if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
"_obj_loadimage: file has no section names\n");
goto out;
}
ef->shstrindex = hdr->e_shstrndx;
lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
lastaddr += shdr[ef->shstrindex].sh_size;
/* Relocation tables. */
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_REL:
case SHT_RELA:
lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
shdr[i].sh_addr = (Elf_Addr)lastaddr;
lastaddr += shdr[i].sh_size;
break;
}
}
/* Clear the whole area, including bss regions. */
kern_bzero(firstaddr, lastaddr - firstaddr);
/* Now read it all in. */
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_addr == 0 || shdr[i].sh_type == SHT_NOBITS)
continue;
if (kern_pread(ef->fd, (vm_offset_t)shdr[i].sh_addr,
shdr[i].sh_size, (off_t)shdr[i].sh_offset) != 0) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
"_obj_loadimage: read failed\n");
goto out;
}
}
file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
res = __elfN(obj_parse_modmetadata)(fp, ef);
if (res != 0)
goto out;
ret = lastaddr - firstaddr;
fp->f_addr = firstaddr;
printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr);
out:
printf("\n");
return ret;
}
#if defined(__i386__) && __ELF_WORD_SIZE == 64
struct mod_metadata64 {
int md_version; /* structure version MDTV_* */
int md_type; /* type of entry MDT_* */
u_int64_t md_data; /* specific data */
u_int64_t md_cval; /* common string label */
};
#endif
int
__elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
{
struct mod_metadata md;
#if defined(__i386__) && __ELF_WORD_SIZE == 64
struct mod_metadata64 md64;
#endif
struct mod_depend *mdepend;
struct mod_version mver;
char *s;
int error, modcnt, minfolen;
Elf_Addr v, p, p_stop;
if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
&modcnt) != 0)
return ENOENT;
modcnt = 0;
while (p < p_stop) {
COPYOUT(p, &v, sizeof(v));
error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v));
if (error != 0)
return (error);
#if defined(__i386__) && __ELF_WORD_SIZE == 64
COPYOUT(v, &md64, sizeof(md64));
error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
if (error != 0)
return (error);
md.md_version = md64.md_version;
md.md_type = md64.md_type;
md.md_cval = (const char *)(uintptr_t)md64.md_cval;
md.md_data = (void *)(uintptr_t)md64.md_data;
#else
COPYOUT(v, &md, sizeof(md));
error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md));
if (error != 0)
return (error);
#endif
p += sizeof(Elf_Addr);
switch(md.md_type) {
case MDT_DEPEND:
s = strdupout((vm_offset_t)md.md_cval);
minfolen = sizeof(*mdepend) + strlen(s) + 1;
mdepend = malloc(minfolen);
if (mdepend == NULL)
return ENOMEM;
COPYOUT((vm_offset_t)md.md_data, mdepend,
sizeof(*mdepend));
strcpy((char*)(mdepend + 1), s);
free(s);
file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
mdepend);
free(mdepend);
break;
case MDT_VERSION:
s = strdupout((vm_offset_t)md.md_cval);
COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
file_addmodule(fp, s, mver.mv_version, NULL);
free(s);
modcnt++;
break;
case MDT_MODULE:
break;
default:
printf("unknown type %d\n", md.md_type);
break;
}
}
return 0;
}
static int
__elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef,
const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
{
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
char *p;
vm_offset_t shstrtab;
int i;
hdr = &ef->hdr;
shdr = ef->e_shdr;
shstrtab = shdr[ef->shstrindex].sh_addr;
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_type != SHT_PROGBITS)
continue;
if (shdr[i].sh_name == 0)
continue;
p = strdupout(shstrtab + shdr[i].sh_name);
if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
*startp = shdr[i].sh_addr;
*stopp = shdr[i].sh_addr + shdr[i].sh_size;
*countp = (*stopp - *startp) / sizeof(Elf_Addr);
free(p);
return (0);
}
free(p);
}
return (ESRCH);
}
/*
* Apply any intra-module relocations to the value. p is the load address
* of the value and val/len is the value to be modified. This does NOT modify
* the image in-place, because this is done by kern_linker later on.
*/
static int
__elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p,
void *val, size_t len)
{
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
Elf_Addr off = p;
Elf_Addr base;
Elf_Rela a, *abase;
Elf_Rel r, *rbase;
int error, i, j, nrel, nrela;
hdr = &ef->hdr;
shdr = ef->e_shdr;
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
continue;
base = shdr[shdr[i].sh_info].sh_addr;
if (base == 0 || shdr[i].sh_addr == 0)
continue;
if (off < base || off + len > base +
shdr[shdr[i].sh_info].sh_size)
continue;
switch (shdr[i].sh_type) {
case SHT_RELA:
abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
nrela = shdr[i].sh_size / sizeof(Elf_Rela);
for (j = 0; j < nrela; j++) {
COPYOUT(abase + j, &a, sizeof(a));
error = __elfN(reloc)(ef, __elfN(obj_symaddr),
&a, ELF_RELOC_RELA, base, off, val, len);
if (error != 0)
return (error);
}
break;
case SHT_REL:
rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
nrel = shdr[i].sh_size / sizeof(Elf_Rel);
for (j = 0; j < nrel; j++) {
COPYOUT(rbase + j, &r, sizeof(r));
error = __elfN(reloc)(ef, __elfN(obj_symaddr),
&r, ELF_RELOC_REL, base, off, val, len);
if (error != 0)
return (error);
}
break;
}
}
return (0);
}
/* Look up the address of a specified symbol. */
static Elf_Addr
__elfN(obj_symaddr)(struct elf_file *ef, Elf_Word symidx)
{
Elf_Sym sym;
Elf_Addr base;
int symcnt;
symcnt = ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym);
if (symidx >= symcnt)
return (0);
COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym),
&sym, sizeof(sym));
if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
return (0);
base = ef->e_shdr[sym.st_shndx].sh_addr;
if (base == 0)
return (0);
return (base + sym.st_value);
}