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freebsd-dev/sys/kern/link_aout.c

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/*-
* Copyright (c) 1997-2000 Doug Rabson
* 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.
*
* $FreeBSD$
*/
#ifdef __i386__
#define FREEBSD_AOUT 1
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/linker.h>
#include "linker_if.h"
#ifndef __ELF__
#include <vm/vm.h>
#include <vm/pmap.h>
#include <machine/vmparam.h>
#endif
#include <a.out.h>
#include <link.h>
typedef struct aout_file {
struct linker_file lf; /* Common fields */
int preloaded; /* Was this pre-loader */
char* address; /* Load address */
struct _dynamic* dynamic; /* Symbol table etc. */
} *aout_file_t;
static int link_aout_link_preload(linker_class_t lc,
const char* modname, linker_file_t*);
static int link_aout_link_preload_finish(linker_file_t);
static int link_aout_load_file(linker_class_t lc, const char*, linker_file_t*);
static int link_aout_lookup_symbol(linker_file_t, const char*,
c_linker_sym_t*);
static int link_aout_symbol_values(linker_file_t file, c_linker_sym_t sym,
linker_symval_t* symval);
static int link_aout_search_symbol(linker_file_t lf, caddr_t value,
c_linker_sym_t* sym, long* diffp);
static void link_aout_unload_file(linker_file_t);
static void link_aout_unload_preload(linker_file_t);
static int link_aout_lookup_set(linker_file_t, const char*,
void ***, void ***, int*);
static kobj_method_t link_aout_methods[] = {
KOBJMETHOD(linker_lookup_symbol, link_aout_lookup_symbol),
KOBJMETHOD(linker_symbol_values, link_aout_symbol_values),
KOBJMETHOD(linker_search_symbol, link_aout_search_symbol),
KOBJMETHOD(linker_unload, link_aout_unload_file),
KOBJMETHOD(linker_load_file, link_aout_load_file),
KOBJMETHOD(linker_link_preload, link_aout_link_preload),
KOBJMETHOD(linker_link_preload_finish, link_aout_link_preload_finish),
KOBJMETHOD(linker_lookup_set, link_aout_lookup_set),
{ 0, 0 }
};
static struct linker_class link_aout_class = {
"a.out", link_aout_methods, sizeof(struct aout_file)
};
static int relocate_file(aout_file_t af);
/*
* The kernel symbol table starts here.
*/
extern struct _dynamic __DYNAMIC;
static void
link_aout_init(void* arg)
{
#ifndef __ELF__
struct _dynamic* dp = &__DYNAMIC;
#endif
linker_add_class(&link_aout_class);
#ifndef __ELF__
if (dp) {
aout_file_t af;
linker_kernel_file =
linker_make_file(kernelname, &link_aout_class);
if (linker_kernel_file == NULL)
panic("link_aout_init: Can't create linker structures for kernel");
af = (aout_file_t) linker_kernel_file;
af->address = 0;
af->dynamic = dp;
linker_kernel_file->address = (caddr_t) KERNBASE;
linker_kernel_file->size = -(long)linker_kernel_file->address;
}
#endif
}
SYSINIT(link_aout, SI_SUB_KLD, SI_ORDER_THIRD, link_aout_init, 0);
static int
link_aout_link_preload(linker_class_t lc,
const char* filename, linker_file_t* result)
{
caddr_t modptr, baseptr;
char *type;
struct exec *ehdr;
aout_file_t af;
linker_file_t lf;
/* Look to see if we have the module preloaded. */
modptr = preload_search_by_name(filename);
if (modptr == NULL)
return ENOENT;
if (((type = (char *)preload_search_info(modptr, MODINFO_TYPE)) == NULL) ||
strcmp(type, "a.out module") ||
((baseptr = preload_search_info(modptr, MODINFO_ADDR)) == NULL) ||
((ehdr = (struct exec *)preload_search_info(modptr, MODINFO_METADATA | MODINFOMD_AOUTEXEC)) == NULL))
return(0); /* we can't handle this */
/* Register with kld */
lf = linker_make_file(filename, &link_aout_class);
if (lf == NULL) {
return(ENOMEM);
}
af = (aout_file_t) lf;
/* Looks like we can handle this one */
filename = preload_search_info(modptr, MODINFO_NAME);
af->preloaded = 1;
af->address = baseptr;
/* Assume _DYNAMIC is the first data item. */
af->dynamic = (struct _dynamic*)(af->address + ehdr->a_text);
if (af->dynamic->d_version != LD_VERSION_BSD) {
linker_file_unload(lf);
return(0); /* we can't handle this */
}
af->dynamic->d_un.d_sdt = (struct section_dispatch_table *)
((char *)af->dynamic->d_un.d_sdt + (vm_offset_t)af->address);
lf->address = af->address;
lf->size = ehdr->a_text + ehdr->a_data + ehdr->a_bss;
*result = lf;
return(0);
}
static int
link_aout_link_preload_finish(linker_file_t lf)
{
aout_file_t af;
int error;
af = (aout_file_t) lf;
error = relocate_file(af);
if (error) {
linker_file_unload(lf);
return(error);
}
return(0);
}
static int
link_aout_load_file(linker_class_t lc, const char* filename, linker_file_t* result)
{
struct nameidata nd;
struct thread *td = curthread; /* XXX */
struct proc *p = td->td_proc;
int error = 0;
int resid, flags;
struct exec header;
aout_file_t af;
linker_file_t lf = 0;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
flags = FREAD;
error = vn_open(&nd, &flags, 0);
if (error)
return error;
NDFREE(&nd, NDF_ONLY_PNBUF);
/*
* Read the a.out header from the file.
*/
error = vn_rdwr(UIO_READ, nd.ni_vp, (void*) &header, sizeof header, 0,
UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
if (error)
goto out;
if (N_BADMAG(header) || !(N_GETFLAG(header) & EX_DYNAMIC))
goto out;
/*
* We have an a.out file, so make some space to read it in.
*/
lf = linker_make_file(filename, &link_aout_class);
if (lf == NULL) {
error = ENOMEM;
goto out;
}
af = (aout_file_t) lf;
af->address = malloc(header.a_text + header.a_data + header.a_bss,
M_LINKER, M_WAITOK);
/*
* Read the text and data sections and zero the bss.
*/
error = vn_rdwr(UIO_READ, nd.ni_vp, (void*) af->address,
header.a_text + header.a_data, 0,
UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td);
if (error)
goto out;
bzero(af->address + header.a_text + header.a_data, header.a_bss);
/*
* Assume _DYNAMIC is the first data item.
*/
af->dynamic = (struct _dynamic*) (af->address + header.a_text);
if (af->dynamic->d_version != LD_VERSION_BSD) {
error = ENOEXEC;
goto out;
}
af->dynamic->d_un.d_sdt = (struct section_dispatch_table *)
((char *)af->dynamic->d_un.d_sdt + (vm_offset_t)af->address);
lf->address = af->address;
lf->size = header.a_text + header.a_data + header.a_bss;
error = linker_load_dependencies(lf);
if (error)
goto out;
error = relocate_file(af);
if (error)
goto out;
*result = lf;
out:
if (error && lf)
linker_file_unload(lf);
VOP_UNLOCK(nd.ni_vp, 0, td);
vn_close(nd.ni_vp, FREAD, p->p_ucred, td);
return error;
}
static void
link_aout_unload_file(linker_file_t file)
{
aout_file_t af = (aout_file_t) file;
if (af->preloaded) {
link_aout_unload_preload(file);
return;
}
if (af->address)
free(af->address, M_LINKER);
}
static void
link_aout_unload_preload(linker_file_t file)
{
if (file->filename)
preload_delete_name(file->filename);
}
/*
* XXX i386 dependant.
*/
static long
read_relocation(struct relocation_info* r, char* addr)
{
int length = r->r_length;
if (length == 0)
return *(u_char*) addr;
else if (length == 1)
return *(u_short*) addr;
else if (length == 2)
return *(u_int*) addr;
else
printf("link_aout: unsupported relocation size %d\n", r->r_length);
return 0;
}
static void
write_relocation(struct relocation_info* r, char* addr, long value)
{
int length = r->r_length;
if (length == 0)
*(u_char*) addr = value;
else if (length == 1)
*(u_short*) addr = value;
else if (length == 2)
*(u_int*) addr = value;
else
printf("link_aout: unsupported relocation size %d\n", r->r_length);
}
#define AOUT_RELOC(af, type, off) (type*) ((af)->address + (off))
static int
relocate_file(aout_file_t af)
{
struct relocation_info* rel;
struct relocation_info* erel;
struct relocation_info* r;
struct nzlist* symbolbase;
char* stringbase;
struct nzlist* np;
char* sym;
long relocation;
rel = AOUT_RELOC(af, struct relocation_info, LD_REL(af->dynamic));
erel = AOUT_RELOC(af, struct relocation_info,
LD_REL(af->dynamic) + LD_RELSZ(af->dynamic));
symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
for (r = rel; r < erel; r++) {
char* addr;
if (r->r_address == 0)
break;
addr = AOUT_RELOC(af, char, r->r_address);
if (r->r_extern) {
np = &symbolbase[r->r_symbolnum];
sym = &stringbase[np->nz_strx];
if (sym[0] != '_') {
printf("link_aout: bad symbol name %s\n", sym);
relocation = 0;
} else
relocation = (intptr_t)
linker_file_lookup_symbol(&af->lf, sym + 1,
np->nz_type != (N_SETV+N_EXT));
if (!relocation) {
printf("link_aout: symbol %s not found\n", sym);
return ENOENT;
}
relocation += read_relocation(r, addr);
if (r->r_jmptable) {
printf("link_aout: can't cope with jump table relocations\n");
continue;
}
if (r->r_pcrel)
relocation -= (intptr_t) af->address;
if (r->r_copy) {
printf("link_aout: can't cope with copy relocations\n");
continue;
}
write_relocation(r, addr, relocation);
} else {
write_relocation(r, addr,
(intptr_t)(read_relocation(r, addr) + af->address));
}
}
return 0;
}
static long
symbol_hash_value(aout_file_t af, 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(af->dynamic);
}
int
link_aout_lookup_symbol(linker_file_t file, const char* name,
c_linker_sym_t* sym)
{
aout_file_t af = (aout_file_t) file;
long hashval;
struct rrs_hash* hashbase;
struct nzlist* symbolbase;
char* stringbase;
struct rrs_hash* hp;
struct nzlist* np;
char* cp;
if (LD_BUCKETS(af->dynamic) == 0)
return 0;
hashbase = AOUT_RELOC(af, struct rrs_hash, LD_HASH(af->dynamic));
symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
restart:
hashval = symbol_hash_value(af, name);
hp = &hashbase[hashval];
if (hp->rh_symbolnum == -1)
return ENOENT;
while (hp) {
np = (struct nzlist *) &symbolbase[hp->rh_symbolnum];
cp = stringbase + np->nz_strx;
/*
* Note: we fake the leading '_' for C symbols.
*/
if (cp[0] == '_' && !strcmp(cp + 1, name))
break;
if (hp->rh_next == 0)
hp = NULL;
else
hp = &hashbase[hp->rh_next];
}
if (hp == NULL)
/*
* Not found.
*/
return ENOENT;
/*
* Check for an aliased symbol, whatever that is.
*/
if (np->nz_type == N_INDR+N_EXT) {
name = stringbase + (++np)->nz_strx + 1; /* +1 for '_' */
goto restart;
}
/*
* Check this is an actual definition of the symbol.
*/
if (np->nz_value == 0)
return ENOENT;
if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
if (np->nz_other == AUX_FUNC)
/* weak function */
return ENOENT;
}
*sym = (linker_sym_t) np;
return 0;
}
static int
link_aout_symbol_values(linker_file_t file, c_linker_sym_t sym,
linker_symval_t* symval)
{
aout_file_t af = (aout_file_t) file;
const struct nzlist* np = (const struct nzlist*) sym;
char* stringbase;
long numsym = LD_STABSZ(af->dynamic) / sizeof(struct nzlist);
struct nzlist *symbase;
/* Is it one of ours? It could be another module... */
symbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
if (np < symbase)
return ENOENT;
if ((np - symbase) > numsym)
return ENOENT;
stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
symval->name = stringbase + np->nz_strx + 1; /* +1 for '_' */
if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
symval->value = 0;
symval->size = np->nz_value;
} else {
symval->value = AOUT_RELOC(af, char, np->nz_value);
symval->size = np->nz_size;
}
return 0;
}
static int
link_aout_search_symbol(linker_file_t lf, caddr_t value,
c_linker_sym_t* sym, long* diffp)
{
aout_file_t af = (aout_file_t) lf;
u_long off = (uintptr_t) (void *) value;
u_long diff = off;
u_long sp_nz_value;
struct nzlist* sp;
struct nzlist* ep;
struct nzlist* best = 0;
for (sp = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic)),
ep = (struct nzlist *) ((caddr_t) sp + LD_STABSZ(af->dynamic));
sp < ep; sp++) {
if (sp->nz_name == 0)
continue;
sp_nz_value = sp->nz_value + (uintptr_t) (void *) af->address;
if (off >= sp_nz_value) {
if (off - sp_nz_value < diff) {
diff = off - sp_nz_value;
best = sp;
if (diff == 0)
break;
} else if (off - sp_nz_value == diff) {
best = sp;
}
}
}
if (best == 0)
*diffp = off;
else
*diffp = diff;
*sym = (linker_sym_t) best;
return 0;
}
/*
* Look up a linker set on an a.out + gnu LD system.
*/
struct generic_linker_set {
int ls_length;
void *ls_items[1];
};
static int
link_aout_lookup_set(linker_file_t lf, const char *name,
void ***startp, void ***stopp, int *countp)
{
c_linker_sym_t sym;
linker_symval_t symval;
void **start, **stop;
int error, count;
struct generic_linker_set *setp;
error = link_aout_lookup_symbol(lf, name, &sym);
if (error)
return error;
link_aout_symbol_values(lf, sym, &symval);
if (symval.value == 0)
return ESRCH;
setp = (struct generic_linker_set *)symval.value;
count = setp->ls_length;
start = &setp->ls_items[0];
stop = &setp->ls_items[count];
if (startp)
*startp = start;
if (stopp)
*stopp = stop;
if (countp)
*countp = count;
return 0;
}
#endif /* __i386__ */
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