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freebsd-nq/sys/boot/common/load_aout.c

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/*-
* Copyright (c) 1998 Michael Smith <msmith@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_aout.c,v 1.6 1998/09/26 10:51:38 dfr Exp $
*/
#include <sys/param.h>
#include <sys/exec.h>
#include <sys/imgact_aout.h>
#include <sys/reboot.h>
#include <string.h>
#include <machine/bootinfo.h>
#include <stand.h>
#include <a.out.h>
#define FREEBSD_AOUT
#include <link.h>
#include "bootstrap.h"
static int aout_loadimage(int fd, vm_offset_t loadaddr, struct exec *ehdr, int kernel);
static vm_offset_t aout_findkldident(struct loaded_module *mp, struct exec *ehdr);
static int aout_fixupkldmod(struct loaded_module *mp, struct exec *ehdr);
char *aout_kerneltype = "a.out kernel";
char *aout_moduletype = "a.out module";
/*
* Attempt to load the file (file) as an a.out module. It will be stored at
* (dest), and a pointer to a module structure describing the loaded object
* will be saved in (result).
*/
int
aout_loadmodule(char *filename, vm_offset_t dest, struct loaded_module **result)
{
struct loaded_module *mp, *kmp;
struct exec ehdr;
int fd;
vm_offset_t addr;
int err, kernel;
u_int pad;
mp = NULL;
/*
* Open the image, read and validate the a.out header
*/
if (filename == NULL) /* can't handle nameless */
return(EFTYPE);
if ((fd = open(filename, O_RDONLY)) == -1)
return(errno);
if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr)) {
err = EFTYPE; /* could be EIO, but may be small file */
goto oerr;
}
if (N_BADMAG(ehdr)) {
err = EFTYPE;
goto oerr;
}
/*
* Check to see what sort of module we are.
*
* XXX should check N_GETMID()
*/
kmp = mod_findmodule(NULL, NULL);
if (N_GETFLAG(ehdr) == (EX_DYNAMIC | EX_PIC)) {
/* Looks like a kld module */
if (kmp == NULL) {
printf("aout_loadmodule: can't load module before kernel\n");
err = EPERM;
goto oerr;
}
if (strcmp(aout_kerneltype, kmp->m_type)) {
printf("aout_loadmodule: can't load module with kernel type '%s'\n", kmp->m_type);
err = EPERM;
goto oerr;
}
/* Looks OK, got ahead */
kernel = 0;
} else if (N_GETFLAG(ehdr) == 0) {
/* Looks like a kernel */
if (kmp != NULL) {
printf("aout_loadmodule: kernel already loaded\n");
err = EPERM;
goto oerr;
}
/*
* Calculate destination address based on kernel entrypoint
* XXX this is i386-freebsd-aout specific
*/
dest = ehdr.a_entry & 0x100000;
if (dest == 0) {
printf("aout_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 (kernel)
mp->m_name = strdup(filename); /* XXX should we prune the name? */
mp->m_type = strdup(kernel ? aout_kerneltype : aout_moduletype);
/* Page-align the load address */
addr = dest;
pad = (u_int)addr & PAGE_MASK;
if (pad != 0) {
pad = PAGE_SIZE - pad;
addr += pad;
}
mp->m_addr = addr; /* save the aligned load address */
printf("%s at %p\n", filename, (void *) addr);
mp->m_size = aout_loadimage(fd, addr, &ehdr, kernel);
if (mp->m_size == 0)
goto ioerr;
/* Handle KLD module data */
if (!kernel && ((err = aout_fixupkldmod(mp, &ehdr)) != 0))
goto oerr;
/* save exec header as metadata */
mod_addmetadata(mp, MODINFOMD_AOUTEXEC, sizeof(struct exec), &ehdr);
/* Load OK, return module pointer */
*result = (struct loaded_module *)mp;
err = 0;
goto out;
ioerr:
err = EIO;
oerr:
mod_discard(mp);
free(mp);
out:
close(fd);
return(err);
}
/*
* With the file (fd) open on the image, and (ehdr) containing
* the exec header, load the image at (addr)
*
* Fixup the a_bss field in (ehdr) to reflect the padding added to
* align the symbol table.
*/
static int
aout_loadimage(int fd, vm_offset_t loadaddr, struct exec *ehdr, int kernel)
{
u_int pad;
vm_offset_t addr;
int ss;
addr = loadaddr;
lseek(fd, N_TXTOFF(*ehdr), SEEK_SET);
/* text segment */
printf(" text=0x%lx ", ehdr->a_text);
if (archsw.arch_readin(fd, addr, ehdr->a_text) != ehdr->a_text)
return(0);
addr += ehdr->a_text;
/* data segment */
printf("data=0x%lx ", ehdr->a_data);
if (archsw.arch_readin(fd, addr, ehdr->a_data) != ehdr->a_data)
return(0);
addr += ehdr->a_data;
/* For kernels, we pad the BSS to a page boundary */
if (kernel) {
pad = (u_int)ehdr->a_bss & PAGE_MASK;
if (pad != 0) {
pad = PAGE_SIZE - pad;
ehdr->a_bss += pad;
}
}
printf("bss=0x%lx ", ehdr->a_bss);
addr += ehdr->a_bss;
/* symbol table size */
archsw.arch_copyin(&ehdr->a_syms, addr, sizeof(ehdr->a_syms));
addr += sizeof(ehdr->a_syms);
/* symbol table */
printf("symbols=[0x%lx+0x%lx", sizeof(ehdr->a_syms), ehdr->a_syms);
if (archsw.arch_readin(fd, addr, ehdr->a_syms) != ehdr->a_syms)
return(0);
addr += ehdr->a_syms;
/* string table */
read(fd, &ss, sizeof(ss));
archsw.arch_copyin(&ss, addr, sizeof(ss));
addr += sizeof(ss);
ss -= sizeof(ss);
printf("+0x%lx+0x%x]", sizeof(ss), ss);
if (archsw.arch_readin(fd, addr, ss) != ss)
return(0);
printf(" \n");
addr += ss;
return(addr - loadaddr);
}
#define AOUT_RELOC(mp, off) ((mp)->m_addr + (vm_offset_t)(off))
/*
* The goal here is to find the one symbol in the loaded object
* which fits the format "kld_identifier_<something>. If there's
* more than one, we fail.
*/
static vm_offset_t
aout_findkldident(struct loaded_module *mp, struct exec *ehdr)
{
/* XXX much of this can go when we can address the load area directly */
vm_offset_t sp, ep, cand, stringbase, result;
struct _dynamic dynamic;
struct section_dispatch_table sdt;
struct nzlist nzl;
char *np;
int match;
/* Get the _DYNAMIC object, which we assume is first in the data segment */
archsw.arch_copyout(AOUT_RELOC(mp, ehdr->a_text), &dynamic, sizeof(dynamic));
archsw.arch_copyout(AOUT_RELOC(mp, dynamic.d_un.d_sdt), &sdt, sizeof(struct section_dispatch_table));
dynamic.d_un.d_sdt = &sdt; /* fix up SDT pointer */
if (dynamic.d_version != LD_VERSION_BSD)
return(0);
stringbase = AOUT_RELOC(mp, LD_STRINGS(&dynamic));
/* start pointer */
sp = AOUT_RELOC(mp, LD_SYMBOL(&dynamic));
/* end pointer */
ep = sp + LD_STABSZ(&dynamic);
/*
* Walk the entire table comparing names.
*/
match = 0;
result = 0;
for (cand = sp; cand < ep; cand += sizeof(struct nzlist)) {
/* get the entry, check for a name */
archsw.arch_copyout(cand, &nzl, sizeof(struct nzlist));
/* is this symbol worth looking at? */
if ((nzl.nz_strx == 0) || /* no name */
(nzl.nz_value == 0) || /* not a definition */
((nzl.nz_type == N_UNDF+N_EXT) &&
(nzl.nz_value != 0) &&
(nzl.nz_other == AUX_FUNC))) /* weak function */
continue;
np = strdupout(stringbase + nzl.nz_strx);
match = (np[0] == '_') && !strncmp(KLD_IDENT_SYMNAME, np + 1, strlen(KLD_IDENT_SYMNAME));
free(np);
if (match) {
/* duplicates? */
if (result)
return(0);
result = AOUT_RELOC(mp, nzl.nz_value);
}
}
return(result);
}
/*
* Perform extra housekeeping associated with loading a KLD module.
*
* XXX if this returns an error, it seems the heap becomes corrupted.
*/
static int
aout_fixupkldmod(struct loaded_module *mp, struct exec *ehdr)
{
struct kld_module_identifier kident;
struct kld_module_dependancy *kdeps;
vm_offset_t vp;
size_t dsize;
/* Find the KLD identifier */
if ((vp = aout_findkldident(mp, ehdr)) == 0) {
printf("bad a.out module format\n");
return(EFTYPE);
}
archsw.arch_copyout(vp, &kident, sizeof(struct kld_module_identifier));
/* Name the module using the name from the KLD data */
if (mod_findmodule(kident.ki_name, NULL) != NULL) {
printf("module '%s' already loaded\n", kident.ki_name);
return(EPERM);
}
mp->m_name = strdup(kident.ki_name);
/* Save the module identifier */
mod_addmetadata(mp, MODINFOMD_KLDIDENT, sizeof(struct kld_module_identifier), &kident);
/* Look for dependancy data, add to metadata list */
if (kident.ki_ndeps > 0) {
dsize = kident.ki_ndeps * kident.ki_depsize;
kdeps = malloc(dsize);
archsw.arch_copyout(AOUT_RELOC(mp, kident.ki_deps), kdeps, dsize);
mod_addmetadata(mp, MODINFOMD_KLDDEP, dsize, kdeps);
free(kdeps);
}
return(0);
}
#if 0
/************************************************************/
/* XXX Arbitrary symbol lookup - unused at this point XXX */
/* */
/* Code heavily borrowed from kern/link_aout.c (c) DFR */
/************************************************************/
static long
symbol_hash_value(struct _dynamic *dynamic, const char* name)
{
long hashval;
const char* p;
hashval = '_'; /* fake a starting '_' for C symbols */
for (p = name; *p; p++)
hashval = (hashval << 1) + *p;
return (hashval & 0x7fffffff) % LD_BUCKETS(dynamic);
}
/*
* Locate the symbol (name) in the a.out object associated with (mp),
* return a vm_offset_t containing the value of the symbol.
*/
static vm_offset_t
aout_findsym(char *name, struct loaded_module *mp)
{
struct module_metadata *md;
struct exec *ehdr;
struct _dynamic dynamic;
struct section_dispatch_table sdt;
vm_offset_t hashbase, symbolbase, stringbase, hp, np, cp;
struct rrs_hash hash;
struct nzlist nzl;
char *symbol, *asymbol; /* XXX symbol name limit? */
long hashval;
vm_offset_t result;
symbol = NULL;
asymbol = NULL;
result = 0;
/* Find the exec header */
if ((md = mod_findmetadata(mp, MODINFOMD_AOUTEXEC)) == NULL)
goto out;
ehdr = (struct exec *)md->md_data;
/* Get the _DYNAMIC object, which we assume is first in the data segment */
archsw.arch_copyout(AOUT_RELOC(mp, ehdr->a_text), &dynamic, sizeof(dynamic));
archsw.arch_copyout(AOUT_RELOC(mp, dynamic.d_un.d_sdt), &sdt, sizeof(struct section_dispatch_table));
dynamic.d_un.d_sdt = &sdt; /* fix up SDT pointer */
if ((dynamic.d_version != LD_VERSION_BSD) ||
(LD_BUCKETS(&dynamic) == 0))
goto out;
hashbase = AOUT_RELOC(mp, LD_HASH(&dynamic));
symbolbase = AOUT_RELOC(mp, LD_SYMBOL(&dynamic));
stringbase = AOUT_RELOC(mp, LD_STRINGS(&dynamic));
restart:
hashval = symbol_hash_value(&dynamic, name);
hp = hashbase + (hashval * sizeof(struct rrs_hash));
archsw.arch_copyout(hp, &hash, sizeof(struct rrs_hash));
if (hash.rh_symbolnum == -1)
goto out;
while (hp) {
np = symbolbase + (hash.rh_symbolnum * sizeof(struct nzlist));
archsw.arch_copyout(np, &nzl, sizeof(struct nzlist));
cp = stringbase + nzl.nz_strx;
if (symbol != NULL)
free(symbol);
symbol = strdupout(cp);
/*
* Note: we fake the leading '_' for C symbols.
*/
if (symbol[0] == '_' && !strcmp(symbol + 1, name))
break;
if (hash.rh_next == 0) {
hp = 0;
} else {
hp = hashbase + (hash.rh_next * sizeof(struct rrs_hash));
archsw.arch_copyout(hp, &hash, sizeof(struct rrs_hash));
}
}
/* Not found. */
if (hp == 0)
goto out;
/*
* Check for an aliased symbol, whatever that is.
*/
if (nzl.nz_type == N_INDR+N_EXT) {
np += sizeof(struct nzlist);
archsw.arch_copyout(np, &nzl, sizeof(struct nzlist));
asymbol = strdupout(stringbase + nzl.nz_strx + 1); /* +1 for '_' */
goto restart;
}
/*
* Check this is an actual definition of the symbol.
*/
if (nzl.nz_value == 0)
goto out;
if (nzl.nz_type == N_UNDF+N_EXT && nzl.nz_value != 0)
if (nzl.nz_other == AUX_FUNC)
/* weak function */
goto out;
/* Return a vm_offset_t pointing to the object itself */
result = AOUT_RELOC(mp, nzl.nz_value);
out:
if (symbol)
free(symbol);
if (asymbol)
free(asymbol);
return(result);
}
#endif
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