freebsd-nq/sys/boot/common/load_elf.c
Peter Wemm a6575097c6 Load the first page of the file and use the headers in it. This should
avoid the need to seek back to offset zero which is causing trouble on
the Alpha with a gzipped kernel.
1998-10-17 03:06:38 +00:00

517 lines
13 KiB
C

/*-
* 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.
*
* $Id: load_elf.c,v 1.8 1998/10/16 03:04:15 peter Exp $
*/
#include <sys/param.h>
#include <sys/exec.h>
#include <sys/reboot.h>
#include <sys/linker.h>
#include <string.h>
#include <machine/bootinfo.h>
#include <machine/elf.h>
#include <stand.h>
#define FREEBSD_ELF
#include <link.h>
#include "bootstrap.h"
static int elf_loadimage(struct loaded_module *mp, int fd, vm_offset_t loadaddr, Elf_Ehdr *ehdr, int kernel, caddr_t firstpage, int firstlen);
char *elf_kerneltype = "elf kernel";
char *elf_moduletype = "elf 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
elf_loadmodule(char *filename, vm_offset_t dest, struct loaded_module **result)
{
struct loaded_module *mp, *kmp;
Elf_Ehdr *ehdr;
int fd;
int err, kernel;
u_int pad;
char *s;
caddr_t firstpage;
int firstlen;
mp = NULL;
/*
* Open the image, read and validate the ELF header
*/
if (filename == NULL) /* can't handle nameless */
return(EFTYPE);
if ((fd = open(filename, O_RDONLY)) == -1)
return(errno);
firstpage = malloc(PAGE_SIZE);
if (firstpage == NULL)
return(ENOMEM);
firstlen = read(fd, firstpage, PAGE_SIZE);
if (firstlen <= sizeof(ehdr)) {
err = EFTYPE; /* could be EIO, but may be small file */
goto oerr;
}
ehdr = (Elf_Ehdr *)firstpage;
/* Is it ELF? */
if (!IS_ELF(*ehdr)) {
err = EFTYPE;
goto oerr;
}
if (ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */
ehdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
ehdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */
ehdr->e_version != EV_CURRENT ||
ehdr->e_machine != ELF_TARG_MACH) { /* Machine ? */
err = EFTYPE;
goto oerr;
}
/*
* Check to see what sort of module we are.
*/
kmp = mod_findmodule(NULL, NULL);
if (ehdr->e_type == ET_DYN) {
/* Looks like a kld module */
if (kmp == NULL) {
printf("elf_loadmodule: can't load module before kernel\n");
err = EPERM;
goto oerr;
}
if (strcmp(elf_kerneltype, kmp->m_type)) {
printf("elf_loadmodule: can't load module with kernel type '%s'\n", kmp->m_type);
err = EPERM;
goto oerr;
}
/* Looks OK, got ahead */
kernel = 0;
/* Page-align the load address */
pad = (u_int)dest & PAGE_MASK;
if (pad != 0) {
pad = PAGE_SIZE - pad;
dest += pad;
}
} else if (ehdr->e_type == ET_EXEC) {
/* Looks like a kernel */
if (kmp != NULL) {
printf("elf_loadmodule: kernel already loaded\n");
err = EPERM;
goto oerr;
}
/*
* Calculate destination address based on kernel entrypoint
*/
dest = (vm_offset_t) ehdr->e_entry;
if (dest == 0) {
printf("elf_loadmodule: not a kernel (maybe static binary?)\n");
err = EPERM;
goto oerr;
}
kernel = 1;
} else {
err = EFTYPE;
goto oerr;
}
/*
* Ok, we think we should handle this.
*/
mp = mod_allocmodule();
if (mp == NULL) {
printf("elf_loadmodule: cannot allocate module info\n");
err = EPERM;
goto out;
}
if (kernel)
setenv("kernelname", filename, 1);
s = strrchr(filename, '/');
if (s)
mp->m_name = strdup(s + 1);
else
mp->m_name = strdup(filename);
mp->m_type = strdup(kernel ? elf_kerneltype : elf_moduletype);
#ifdef ELF_VERBOSE
if (kernel)
printf("%s entry at %p\n", filename, (void *) dest);
#else
printf("%s ", filename);
#endif
mp->m_size = elf_loadimage(mp, fd, dest, ehdr, kernel, firstpage, firstlen);
if (mp->m_size == 0 || mp->m_addr == 0)
goto ioerr;
/* save exec header as metadata */
mod_addmetadata(mp, MODINFOMD_ELFHDR, sizeof(*ehdr), ehdr);
/* Load OK, return module pointer */
*result = (struct loaded_module *)mp;
err = 0;
goto out;
ioerr:
err = EIO;
oerr:
mod_discard(mp);
out:
if (firstpage)
free(firstpage);
close(fd);
return(err);
}
/*
* With the file (fd) open on the image, and (ehdr) containing
* the Elf header, load the image at (off)
*/
static int
elf_loadimage(struct loaded_module *mp, int fd, vm_offset_t off,
Elf_Ehdr *ehdr, int kernel, caddr_t firstpage, int firstlen)
{
int i, j;
Elf_Phdr *phdr;
Elf_Shdr *shdr;
int ret;
vm_offset_t firstaddr;
vm_offset_t lastaddr;
void *buf;
size_t resid, chunk;
vm_offset_t dest;
vm_offset_t ssym, esym;
Elf_Dyn *dp;
int ndp;
int deplen;
char *depdata;
char *s;
int len;
char *strtab;
size_t strsz;
int symstrindex;
int symtabindex;
long size;
int fpcopy;
dp = NULL;
shdr = NULL;
ret = 0;
firstaddr = lastaddr = 0;
if (kernel) {
#ifdef __i386__
off = 0x10000000; /* -0xf0000000 - i386 relocates after locore */
#else
off = 0; /* alpha is direct mapped for kernels */
#endif
}
if ((ehdr->e_phoff + ehdr->e_phnum * sizeof(*phdr)) > firstlen) {
printf("elf_loadimage: program header not within first page\n");
goto out;
}
phdr = (Elf_Phdr *)(firstpage + ehdr->e_phoff);
for (i = 0; i < ehdr->e_phnum; i++) {
/* We want to load PT_LOAD segments only.. */
if (phdr[i].p_type != PT_LOAD)
continue;
#ifdef ELF_VERBOSE
printf("Segment: 0x%lx@0x%lx -> 0x%lx-0x%lx",
(long)phdr[i].p_filesz, (long)phdr[i].p_offset,
(long)(phdr[i].p_vaddr + off),
(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
#else
if ((phdr[i].p_flags & PF_W) == 0) {
printf("text=0x%lx ", (long)phdr[i].p_filesz);
} else {
printf("data=0x%lx", (long)phdr[i].p_filesz);
if (phdr[i].p_filesz < phdr[i].p_memsz)
printf("+0x%lx", (long)(phdr[i].p_memsz -phdr[i].p_filesz));
printf(" ");
}
#endif
fpcopy = 0;
if (firstlen > phdr[i].p_offset) {
fpcopy = firstlen - phdr[i].p_offset;
archsw.arch_copyin(firstpage + phdr[i].p_offset,
phdr[i].p_vaddr + off, fpcopy);
}
if (phdr[i].p_filesz > fpcopy) {
if (lseek(fd, phdr[i].p_offset + fpcopy, SEEK_SET) == -1) {
printf("\nelf_loadexec: cannot seek\n");
goto out;
}
if (archsw.arch_readin(fd, phdr[i].p_vaddr + off + fpcopy,
phdr[i].p_filesz - fpcopy) != phdr[i].p_filesz - fpcopy) {
printf("\nelf_loadexec: archsw.readin failed\n");
goto out;
}
}
/* clear space from oversized segments; eg: bss */
if (phdr[i].p_filesz < phdr[i].p_memsz) {
#ifdef ELF_VERBOSE
printf(" (bss: 0x%lx-0x%lx)",
(long)(phdr[i].p_vaddr + off + phdr[i].p_filesz),
(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
#endif
/* no archsw.arch_bzero */
buf = malloc(PAGE_SIZE);
bzero(buf, PAGE_SIZE);
resid = phdr[i].p_memsz - phdr[i].p_filesz;
dest = phdr[i].p_vaddr + off + phdr[i].p_filesz;
while (resid > 0) {
chunk = min(PAGE_SIZE, resid);
archsw.arch_copyin(buf, dest, chunk);
resid -= chunk;
dest += chunk;
}
free(buf);
}
#ifdef ELF_VERBOSE
printf("\n");
#endif
if (firstaddr == 0 || firstaddr > (phdr[i].p_vaddr + off))
firstaddr = phdr[i].p_vaddr + off;
if (lastaddr == 0 || lastaddr < (phdr[i].p_vaddr + off + phdr[i].p_memsz))
lastaddr = phdr[i].p_vaddr + off + phdr[i].p_memsz;
}
lastaddr = roundup(lastaddr, sizeof(long));
/*
* Now grab the symbol tables. This isn't easy if we're reading a
* .gz file. I think the rule is going to have to be that you must
* strip a file to remove symbols before gzipping it so that we do not
* try to lseek() on it.
*/
chunk = ehdr->e_shnum * ehdr->e_shentsize;
if (chunk == 0 || ehdr->e_shoff == 0)
goto nosyms;
shdr = malloc(chunk);
if (shdr == NULL)
goto nosyms;
if (lseek(fd, ehdr->e_shoff, SEEK_SET) == -1) {
printf("\nelf_loadimage: cannot lseek() to section headers\n");
goto nosyms;
}
if (read(fd, shdr, chunk) != chunk) {
printf("\nelf_loadimage: read section headers failed\n");
goto nosyms;
}
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < ehdr->e_shnum; i++) {
if (shdr[i].sh_type != SHT_SYMTAB)
continue;
for (j = 0; j < ehdr->e_phnum; j++) {
if (phdr[j].p_type != PT_LOAD)
continue;
if (shdr[i].sh_offset >= phdr[j].p_offset &&
(shdr[i].sh_offset + shdr[i].sh_size <=
phdr[j].p_offset + phdr[j].p_filesz)) {
shdr[i].sh_offset = 0;
shdr[i].sh_size = 0;
break;
}
}
if (shdr[i].sh_offset == 0 || shdr[i].sh_size == 0)
continue; /* alread loaded in a PT_LOAD above */
/* Save it for loading below */
symtabindex = i;
symstrindex = shdr[i].sh_link;
}
if (symtabindex < 0 || symstrindex < 0)
goto nosyms;
/* Ok, committed to a load. */
#ifndef ELF_VERBOSE
printf("syms=[");
#endif
ssym = lastaddr;
for (i = symtabindex; i >= 0; i = symstrindex) {
#ifdef ELF_VERBOSE
char *secname;
switch(shdr[i].sh_type) {
case SHT_SYMTAB: /* Symbol table */
secname = "symtab";
break;
case SHT_STRTAB: /* String table */
secname = "strtab";
break;
default:
secname = "WHOA!!";
break;
}
#endif
size = shdr[i].sh_size;
archsw.arch_copyin(&size, lastaddr, sizeof(size));
lastaddr += sizeof(long);
#ifdef ELF_VERBOSE
printf("%s: 0x%lx@0x%lx -> 0x%lx-0x%lx\n", secname,
shdr[i].sh_size, shdr[i].sh_offset,
lastaddr, lastaddr + shdr[i].sh_size);
#else
if (i == symstrindex)
printf("+");
printf("0x%lx+0x%lx", (long)sizeof(size), size);
#endif
if (lseek(fd, shdr[i].sh_offset, SEEK_SET) == -1) {
printf("\nelf_loadimage: could not seek for symbols - skipped!\n");
lastaddr = ssym;
ssym = 0;
goto nosyms;
}
if (archsw.arch_readin(fd, lastaddr, shdr[i].sh_size) !=
shdr[i].sh_size) {
printf("\nelf_loadimage: could not read symbols - skipped!\n");
lastaddr = ssym;
ssym = 0;
goto nosyms;
}
/* Reset offsets relative to ssym */
lastaddr += shdr[i].sh_size;
lastaddr = roundup(lastaddr, sizeof(long));
if (i == symtabindex)
symtabindex = -1;
else if (i == symstrindex)
symstrindex = -1;
}
esym = lastaddr;
#ifndef ELF_VERBOSE
printf("]\n");
#endif
mod_addmetadata(mp, MODINFOMD_SSYM, sizeof(ssym), &ssym);
mod_addmetadata(mp, MODINFOMD_ESYM, sizeof(esym), &esym);
nosyms:
ret = lastaddr - firstaddr;
mp->m_addr = firstaddr;
for (i = 0; i < ehdr->e_phnum; i++) {
if (phdr[i].p_type == PT_DYNAMIC) {
dp = (Elf_Dyn *)(phdr[i].p_vaddr);
mod_addmetadata(mp, MODINFOMD_DYNAMIC, sizeof(dp), &dp);
dp = NULL;
break;
}
}
if (kernel) /* kernel must not depend on anything */
goto out;
ndp = 0;
for (i = 0; i < ehdr->e_phnum; i++) {
if (phdr[i].p_type == PT_DYNAMIC) {
ndp = phdr[i].p_filesz / sizeof(Elf_Dyn);
dp = malloc(phdr[i].p_filesz);
archsw.arch_copyout(phdr[i].p_vaddr + off, dp, phdr[i].p_filesz);
}
}
if (dp == NULL || ndp == 0)
goto out;
strtab = NULL;
strsz = 0;
deplen = 0;
for (i = 0; i < ndp; i++) {
if (dp[i].d_tag == NULL)
break;
switch (dp[i].d_tag) {
case DT_STRTAB:
strtab = (char *)(dp[i].d_un.d_ptr + off);
break;
case DT_STRSZ:
strsz = dp[i].d_un.d_val;
break;
default:
break;
}
}
if (strtab == NULL || strsz == 0)
goto out;
deplen = 0;
for (i = 0; i < ndp; i++) {
if (dp[i].d_tag == NULL)
break;
switch (dp[i].d_tag) {
case DT_NEEDED: /* count size for dependency list */
j = dp[i].d_un.d_ptr;
if (j < 1 || j > (strsz - 2))
continue; /* bad symbol name index */
deplen += strlenout((vm_offset_t)&strtab[j]) + 1;
break;
default:
break;
}
}
if (deplen > 0) {
depdata = malloc(deplen);
if (depdata == NULL)
goto out;
s = depdata;
for (i = 0; i < ndp; i++) {
if (dp[i].d_tag == NULL)
break;
switch (dp[i].d_tag) {
case DT_NEEDED: /* dependency list */
j = dp[i].d_un.d_ptr;
len = strlenout((vm_offset_t)&strtab[j]) + 1;
archsw.arch_copyout((vm_offset_t)&strtab[j], s, len);
s += len;
break;
default:
break;
}
}
if ((s - depdata) > 0)
mod_addmetadata(mp, MODINFOMD_DEPLIST, s - depdata, depdata);
free(depdata);
}
out:
if (dp)
free(dp);
if (shdr)
free(shdr);
return ret;
}