freebsd-dev/sys/boot/common/load_elf.c

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/*-
* 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);
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#ifdef ELF_VERBOSE
if (kernel)
printf("%s entry at %p\n", filename, (void *) dest);
#else
printf("%s ", filename);
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#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
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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;
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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
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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
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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;
}