OpenBSD-4.6/libexec/ld.so/library_mquery.c
/* $OpenBSD: library_mquery.c,v 1.36 2008/10/02 20:12:08 kurt Exp $ */
/*
* Copyright (c) 2002 Dale Rahn
* Copyright (c) 1998 Per Fogelstrom, Opsycon AB
*
* 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 ``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 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.
*
*/
#define _DYN_LOADER
#include <sys/types.h>
#include <sys/param.h>
#include <fcntl.h>
#include <sys/mman.h>
#include "dl_prebind.h"
#include "syscall.h"
#include "archdep.h"
#include "resolve.h"
#define PFLAGS(X) ((((X) & PF_R) ? PROT_READ : 0) | \
(((X) & PF_W) ? PROT_WRITE : 0) | \
(((X) & PF_X) ? PROT_EXEC : 0))
void
_dl_load_list_free(struct load_list *load_list)
{
struct load_list *next;
Elf_Addr align = _dl_pagesz - 1;
while (load_list != NULL) {
if (load_list->start != NULL)
_dl_munmap(load_list->start,
((load_list->size) + align) & ~align);
next = load_list->next;
_dl_free(load_list);
load_list = next;
}
}
void
_dl_unload_shlib(elf_object_t *object)
{
struct dep_node *n;
DL_DEB(("unload_shlib called on %s\n", object->load_name));
if (OBJECT_REF_CNT(object) == 0 &&
(object->status & STAT_UNLOADED) == 0) {
object->status |= STAT_UNLOADED;
TAILQ_FOREACH(n, &object->child_list, next_sib)
_dl_unload_shlib(n->data);
TAILQ_FOREACH(n, &object->grpref_list, next_sib)
_dl_unload_shlib(n->data);
DL_DEB(("unload_shlib unloading on %s\n", object->load_name));
_dl_load_list_free(object->load_list);
_dl_remove_object(object);
}
}
elf_object_t *
_dl_tryload_shlib(const char *libname, int type, int flags)
{
int libfile, i;
struct load_list *ld, *lowld = NULL;
elf_object_t *object;
Elf_Dyn *dynp = 0;
Elf_Ehdr *ehdr;
Elf_Phdr *phdp;
Elf_Addr load_end = 0;
Elf_Addr align = _dl_pagesz - 1, off, size;
struct stat sb;
void *prebind_data;
char hbuf[4096];
#define ROUND_PG(x) (((x) + align) & ~(align))
#define TRUNC_PG(x) ((x) & ~(align))
object = _dl_lookup_object(libname);
if (object) {
object->obj_flags |= flags & RTLD_GLOBAL;
if (_dl_loading_object == NULL)
_dl_loading_object = object;
if (object->load_object != _dl_objects &&
object->load_object != _dl_loading_object) {
_dl_link_grpref(object->load_object, _dl_loading_object);
}
return(object); /* Already loaded */
}
libfile = _dl_open(libname, O_RDONLY);
if (libfile < 0) {
_dl_errno = DL_CANT_OPEN;
return(0);
}
if ( _dl_fstat(libfile, &sb) < 0) {
_dl_errno = DL_CANT_OPEN;
return(0);
}
for (object = _dl_objects; object != NULL; object = object->next) {
if (object->dev == sb.st_dev &&
object->inode == sb.st_ino) {
object->obj_flags |= flags & RTLD_GLOBAL;
_dl_close(libfile);
if (_dl_loading_object == NULL)
_dl_loading_object = object;
if (object->load_object != _dl_objects &&
object->load_object != _dl_loading_object) {
_dl_link_grpref(object->load_object,
_dl_loading_object);
}
return(object);
}
}
_dl_read(libfile, hbuf, sizeof(hbuf));
ehdr = (Elf_Ehdr *)hbuf;
if (ehdr->e_ident[0] != ELFMAG0 || ehdr->e_ident[1] != ELFMAG1 ||
ehdr->e_ident[2] != ELFMAG2 || ehdr->e_ident[3] != ELFMAG3 ||
ehdr->e_type != ET_DYN || ehdr->e_machine != MACHID) {
_dl_close(libfile);
_dl_errno = DL_NOT_ELF;
return(0);
}
/* Insertion sort */
#define LDLIST_INSERT(ld) do { \
struct load_list **_ld; \
for (_ld = &lowld; *_ld != NULL; _ld = &(*_ld)->next) \
if ((*_ld)->moff > ld->moff) \
break; \
ld->next = *_ld; \
*_ld = ld; \
} while (0)
/*
* Alright, we might have a winner!
* Figure out how much VM space we need and set up the load
* list that we'll use to find free VM space.
*/
phdp = (Elf_Phdr *)(hbuf + ehdr->e_phoff);
for (i = 0; i < ehdr->e_phnum; i++, phdp++) {
switch (phdp->p_type) {
case PT_LOAD:
off = (phdp->p_vaddr & align);
size = off + phdp->p_filesz;
ld = _dl_malloc(sizeof(struct load_list));
ld->start = NULL;
ld->size = size;
ld->moff = TRUNC_PG(phdp->p_vaddr);
ld->foff = TRUNC_PG(phdp->p_offset);
ld->prot = PFLAGS(phdp->p_flags);
LDLIST_INSERT(ld);
if ((ld->prot & PROT_WRITE) == 0 ||
ROUND_PG(size) == ROUND_PG(off + phdp->p_memsz))
break;
/* This phdr has a zfod section */
ld = _dl_malloc(sizeof(struct load_list));
ld->start = NULL;
ld->size = ROUND_PG(off + phdp->p_memsz) -
ROUND_PG(size);
ld->moff = TRUNC_PG(phdp->p_vaddr) +
ROUND_PG(size);
ld->foff = -1;
ld->prot = PFLAGS(phdp->p_flags);
LDLIST_INSERT(ld);
break;
case PT_DYNAMIC:
dynp = (Elf_Dyn *)phdp->p_vaddr;
break;
default:
break;
}
}
#define LOFF ((Elf_Addr)lowld->start - lowld->moff)
retry:
for (ld = lowld; ld != NULL; ld = ld->next) {
off_t foff;
int fd, flags;
/*
* We don't want to provide the fd/off hint for anything
* but the first mapping, all other might have
* cache-incoherent aliases and will cause this code to
* loop forever.
*/
if (ld == lowld) {
fd = libfile;
foff = ld->foff;
flags = 0;
} else {
fd = -1;
foff = 0;
flags = MAP_FIXED;
}
ld->start = (void *)(LOFF + ld->moff);
/*
* Magic here.
* The first mquery is done with MAP_FIXED to see if
* the mapping we want is free. If it's not, we redo the
* mquery without MAP_FIXED to get the next free mapping,
* adjust the base mapping address to match this free mapping
* and restart the process again.
*/
ld->start = _dl_mquery(ld->start, ROUND_PG(ld->size), ld->prot,
flags, fd, foff);
if (_dl_mmap_error(ld->start)) {
ld->start = (void *)(LOFF + ld->moff);
ld->start = _dl_mquery(ld->start, ROUND_PG(ld->size),
ld->prot, flags & ~MAP_FIXED, fd, foff);
if (_dl_mmap_error(ld->start))
goto fail;
}
if (ld->start != (void *)(LOFF + ld->moff)) {
lowld->start = ld->start - ld->moff + lowld->moff;
goto retry;
}
/*
* XXX - we need some kind of boundary condition here,
* or fix mquery to not run into the stack
*/
}
for (ld = lowld; ld != NULL; ld = ld->next) {
int fd, flags;
off_t foff;
void *res;
if (ld->foff < 0) {
fd = -1;
foff = 0;
flags = MAP_FIXED|MAP_PRIVATE|MAP_ANON;
} else {
fd = libfile;
foff = ld->foff;
flags = MAP_FIXED|MAP_PRIVATE;
}
res = _dl_mmap(ld->start, ROUND_PG(ld->size), ld->prot, flags,
fd, foff);
if (_dl_mmap_error(res))
goto fail;
/* Zero out everything past the EOF */
if ((ld->prot & PROT_WRITE) != 0 && (ld->size & align) != 0)
_dl_memset((char *)ld->start + ld->size, 0,
_dl_pagesz - (ld->size & align));
load_end = (Elf_Addr)ld->start + ROUND_PG(ld->size);
}
prebind_data = prebind_load_fd(libfile, libname);
_dl_close(libfile);
dynp = (Elf_Dyn *)((unsigned long)dynp + LOFF);
object = _dl_finalize_object(libname, dynp,
(Elf_Phdr *)((char *)lowld->start + ehdr->e_phoff), ehdr->e_phnum,
type, (Elf_Addr)lowld->start, LOFF);
if (object) {
object->prebind_data = prebind_data;
object->load_size = (Elf_Addr)load_end - (Elf_Addr)lowld->start;
object->load_list = lowld;
/* set inode, dev from stat info */
object->dev = sb.st_dev;
object->inode = sb.st_ino;
object->obj_flags |= flags;
} else {
/* XXX no point. object is never returned NULL */
_dl_load_list_free(lowld);
}
return(object);
fail:
_dl_printf("%s: rtld mmap failed mapping %s.\n",
_dl_progname, libname);
_dl_close(libfile);
_dl_errno = DL_CANT_MMAP;
_dl_load_list_free(lowld);
return(0);
}