Aren
/
NetBSD
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
NetBSD/libexec/ld.aout_so/rtld.c

812 lines
18 KiB
C
Raw Blame History

/*
* Copyright (c) 1993 Paul Kranenburg
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Paul Kranenburg.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software withough specific prior written permission
*
* 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.
*
* $Id: rtld.c,v 1.3 1993/10/21 00:00:09 pk Exp $
*/
#include <sys/param.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/mman.h>
#ifdef sun
#define MAP_COPY MAP_PRIVATE
#define MAP_FILE 0
#define MAP_ANON 0
#endif
#include <fcntl.h>
#include <a.out.h>
#include <stab.h>
#include <string.h>
#include <strings.h>
#include "ld.h"
/*
* Loader private data, hung off link_map->lm_lpd
*/
struct lm_private {
int lpd_version;
#ifdef SUN_COMPAT
long lpd_offset; /* Correction for Sun main programs */
#endif
};
#ifdef SUN_COMPAT
#define LM_OFFSET(lmp) (((struct lm_private *)((lmp)->lm_lpd))->lpd_offset)
#else
#define LM_OFFSET(lmp) (0)
#endif
/* Base address for link_dynamic_2 entries */
#define LM_LDBASE(lmp) (lmp->lm_addr + LM_OFFSET(lmp))
/* Start of text segment */
#define LM_TXTADDR(lmp) (lmp->lm_addr == (caddr_t)0 ? PAGSIZ : 0)
/* Start of run-time relocation_info */
#define LM_REL(lmp) ((struct relocation_info *) \
(lmp->lm_addr + LM_OFFSET(lmp) + LD_REL((lmp)->lm_ld)))
/* Start of symbols */
#define LM_SYMBOL(lmp, i) ((struct nzlist *) \
(lmp->lm_addr + LM_OFFSET(lmp) + LD_SYMBOL((lmp)->lm_ld) + \
i * (LD_VERSION_NZLIST_P(lmp->lm_ld->ld_version) ? \
sizeof(struct nzlist) : sizeof(struct nlist))))
/* Start of hash table */
#define LM_HASH(lmp) ((struct rrs_hash *) \
(lmp->lm_addr + LM_OFFSET(lmp) + LD_HASH((lmp)->lm_ld)))
/* Start of strings */
#define LM_STRINGS(lmp) ((char *) \
(lmp->lm_addr + LM_OFFSET(lmp) + LD_STRINGS((lmp)->lm_ld)))
/* End of text */
#define LM_ETEXT(lmp) ((char *) \
(lmp->lm_addr + LM_TXTADDR(lmp) + LD_TEXTSZ((lmp)->lm_ld)))
/* PLT is in data segment, so don't use LM_OFFSET here */
#define LM_PLT(lmp) ((jmpslot_t *) \
(lmp->lm_addr + LD_PLT((lmp)->lm_ld)))
char **environ;
int errno;
struct link_map *link_map_head, *main_map;
struct link_map **link_map_tail = &link_map_head;
struct rt_symbol *rt_symbol_head;
static int dlopen(), dlclose(), dlsym();
static struct ld_entry ld_entry = {
dlopen, dlclose, dlsym
};
static void init_brk __P((void));
static void load_maps __P((struct crt_ldso *));
static void map_object __P((struct link_object *, struct link_map *));
static void alloc_link_map __P(( char *, struct link_object *,
caddr_t, caddr_t,
struct link_dynamic *));
static void check_text_reloc __P(( struct relocation_info *,
struct link_map *,
caddr_t));
static void reloc_maps __P((void));
static void reloc_copy __P((void));
static char *rtfindlib __P((char *, int, int));
void binder_entry __P((void));
long binder __P((jmpslot_t *));
static struct nzlist *lookup __P((char *, struct link_map **));
static struct rt_symbol *lookup_rts __P((char *));
static struct rt_symbol *enter_rts __P((char *, long, int, caddr_t, long));
#include "md-static-funcs.c"
/*
* Called from assembler stub that has set up crtp (passed from crt0)
* and dp (our __DYNAMIC).
*/
void
rtld(version, crtp, dp)
int version;
struct crt_ldso *crtp;
struct link_dynamic *dp;
{
int n;
int nreloc; /* # of ld.so relocations */
struct relocation_info *reloc;
/* Check version */
/* Fixup __DYNAMIC structure */
(long)dp->ld_un.ld_2 += crtp->crt_ba;
/* Be careful not to use .div routine from library */
for ( nreloc = 0, n = LD_RELSZ(dp);
n > 0;
n -= sizeof(struct relocation_info) ) nreloc++;
/* Relocate ourselves */
for ( reloc = (struct relocation_info *)
(dp->ld_un.ld_2->ld_rel + crtp->crt_ba);
nreloc;
nreloc--, reloc++) {
register long addr = reloc->r_address + crtp->crt_ba;
md_relocate_simple(reloc, crtp->crt_ba, addr);
}
progname = "ld.so";
/* Setup out (private) environ variable */
environ = crtp->crt_ep;
/* Setup directory search */
std_search_dirs();
/* Load required objects into the process address space */
load_maps(crtp);
/* Relocate all loaded objects according to their RRS segments */
reloc_maps();
reloc_copy();
/* Fill in some field in main's __DYNAMIC structure */
crtp->crt_dp->ld_entry = &ld_entry;
crtp->crt_dp->ldd->ldd_cp = rt_symbol_head;
}
static void
reloc_copy()
{
struct rt_symbol *rtsp;
for (rtsp = rt_symbol_head; rtsp; rtsp = rtsp->rt_next)
if (rtsp->rt_sp->nz_type == N_DATA + N_EXT) {
#ifdef DEBUG
xprintf("reloc_copy: from %#x to %#x, size %d\n",
rtsp->rt_srcaddr, rtsp->rt_sp->nz_value, rtsp->rt_sp->nz_size);
#endif
bcopy(rtsp->rt_srcaddr, (caddr_t)rtsp->rt_sp->nz_value,
rtsp->rt_sp->nz_size);
}
}
static void
load_maps(crtp)
struct crt_ldso *crtp;
{
struct link_map *lmp;
int tracing = (int)getenv("LD_TRACE_LOADED_OBJECTS");
/* Handle LD_PRELOAD's here */
/* Make an entry for the main program */
alloc_link_map("main", (struct link_object *)0, (caddr_t)0,
(caddr_t)0, crtp->crt_dp);
for (lmp = link_map_head; lmp; lmp = lmp->lm_next) {
struct link_object *lop;
long next = 0;
if (lmp->lm_ld)
next = LD_NEED(lmp->lm_ld);
while (next) {
lop = (struct link_object *) (LM_LDBASE(lmp) + next);
map_object(lop, lmp);
next = lop->lo_next;
}
}
if (! tracing)
return;
for (lmp = link_map_head; lmp; lmp = lmp->lm_next) {
struct link_object *lop;
char *name, *path;
if ((lop = lmp->lm_lop) == NULL)
continue;
name = lop->lo_name + lmp->lm_lob;
if ((path = lmp->lm_name) == NULL)
path = "not found";
if (lop->lo_library)
printf("\t-l%s.%d => %s\n", name, lop->lo_major, path);
else
printf("\t%s => %s\n", name, path);
}
_exit(0);
}
static void
alloc_link_map(name, lop, lob, addr, dp)
char *name;
struct link_object *lop;
caddr_t lob;
caddr_t addr;
struct link_dynamic *dp;
{
struct link_map *lmp;
struct lm_private *lmpp;
lmpp = (struct lm_private *)xmalloc(sizeof(struct lm_private));
lmp = (struct link_map *)xmalloc(sizeof(struct link_map));
lmp->lm_next = NULL;
*link_map_tail = lmp;
link_map_tail = &lmp->lm_next;
lmp->lm_addr = addr;
lmp->lm_name = name;
lmp->lm_lop = lop;
lmp->lm_ld = dp;
lmp->lm_lpd = (caddr_t)lmpp;
lmp->lm_lob = lob;
/*XXX*/ if (addr == 0) main_map = lmp;
#ifdef SUN_COMPAT
lmpp->lpd_offset =
(addr == 0 && dp->ld_version == LD_VERSION_SUN) ? PAGSIZ : 0;
#endif
}
/*
* Map object identified by link object LOP which was found
* in link map LMP.
*/
static void
map_object(lop, lmp)
struct link_object *lop;
struct link_map *lmp;
{
struct link_dynamic *dp;
char *path, *name = (char *)(lop->lo_name + LM_LDBASE(lmp));
int fd;
caddr_t addr;
struct exec hdr;
if (lop->lo_library) {
path = rtfindlib(name, lop->lo_major, lop->lo_minor);
if (path == NULL)
fatal("Cannot find lib%s.so.%d.%d\n",
name, lop->lo_major, lop->lo_minor);
} else {
path = name;
}
fd = open(path, O_RDONLY, 0);
if (fd == -1)
fatal("%s not found", path);
if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
fatal("%s: Cannot read exec header", path);
}
if (N_BADMAG(hdr))
fatal("%s: Incorrect format", path);
if ((addr = mmap(0, hdr.a_text + hdr.a_data,
PROT_READ|PROT_EXEC,
MAP_FILE|MAP_COPY, fd, 0)) == (caddr_t)-1)
fatal("Cannot map %s text\n", path);
if (mmap(addr + hdr.a_text, hdr.a_data,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FILE|MAP_FIXED|MAP_COPY,
fd, hdr.a_text) == (caddr_t)-1)
fatal("Cannot map %s data", path);
close(fd);
fd = -1;
#ifdef sun
if ((fd = open("/dev/zero", O_RDWR, 0)) == -1)
perror("/dev/zero");
#endif
if (hdr.a_bss && mmap(addr + hdr.a_text + hdr.a_data, hdr.a_bss,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_ANON|MAP_FIXED|MAP_COPY,
fd, hdr.a_text + hdr.a_data) == (caddr_t)-1)
fatal("Cannot map %s bss", path);
#ifdef sun
close(fd);
#endif
/* Assume _DYNAMIC is the first data item */
dp = (struct link_dynamic *)(addr+hdr.a_text);
/* Fixup __DYNAMIC structure */
(long)dp->ld_un.ld_2 += (long)addr;
alloc_link_map(path, lop, lmp->lm_addr, addr, dp);
}
static void
reloc_maps()
{
struct link_map *lmp;
for (lmp = link_map_head; lmp; lmp = lmp->lm_next) {
struct link_dynamic *dp = lmp->lm_ld;
struct relocation_info *r = LM_REL(lmp);
struct relocation_info *rend = r + LD_RELSZ(dp)/sizeof(*r);
if (LD_PLTSZ(dp))
md_fix_jmpslot(LM_PLT(lmp),
(long)LM_PLT(lmp), (long)binder_entry);
for (; r < rend; r++) {
char *sym;
caddr_t addr = lmp->lm_addr + r->r_address;
check_text_reloc(r, lmp, addr);
if (RELOC_EXTERN_P(r)) {
struct link_map *src_map;
struct nzlist *np;
long relocation = md_get_addend(r, addr);
if (RELOC_LAZY_P(r))
continue;
sym = LM_STRINGS(lmp) +
LM_SYMBOL(lmp,RELOC_SYMBOL(r))->nz_strx;
np = lookup(sym, &src_map);
if (np == NULL)
fatal("Undefined symbol in %s: %s\n",
lmp->lm_name, sym);
/*
* Found symbol definition.
* If it's in a link map, adjust value
* according to the load address of that map.
* Otherwise it's a run-time allocated common
* whose value is already up-to-date.
*/
relocation += np->nz_value;
if (src_map)
relocation += (long)src_map->lm_addr;
if (RELOC_PCREL_P(r))
relocation -= (long)lmp->lm_addr;
if (RELOC_COPY_P(r) && src_map) {
#if DEBUG
xprintf("RELOCATE(%s) copy: from %s at %#x(%#x+%#x) to %s at %#x, reloc = %#x, size %d\n",
lmp->lm_name, src_map->lm_name, src_map->lm_addr + np->nz_value,
src_map->lm_addr, np->nz_value, sym, addr, relocation, np->nz_size);
#endif
(void)enter_rts(sym,
(long)addr,
N_DATA + N_EXT,
src_map->lm_addr + np->nz_value,
np->nz_size);
continue;
}
#if DEBUG
xprintf("RELOCATE(%s) external: %s at %#x, reloc = %#x\n", lmp->lm_name, sym, addr, relocation);
#endif
md_relocate(r, relocation, addr, 0);
} else {
#if DEBUG
xprintf("RELOCATE(%s) internal at %#x, reloc = %#x\n", lmp->lm_name, addr, md_get_rt_segment_addend(r,addr));
#endif
md_relocate(r,
#ifdef SUN_COMPAT
md_get_rt_segment_addend(r, addr)
#else
md_get_addend(r, addr)
#endif
+ (long)lmp->lm_addr, addr, 0);
}
}
}
}
static void
check_text_reloc(r, lmp, addr)
struct relocation_info *r;
struct link_map *lmp;
caddr_t addr;
{
char *sym;
if (addr >= LM_ETEXT(lmp))
return;
if (RELOC_EXTERN_P(r))
sym = LM_STRINGS(lmp) +
LM_SYMBOL(lmp, RELOC_SYMBOL(r))->nz_strx;
else
sym = "";
fprintf(stderr, "ld.so: warning: non pure code in %s at %x (%s)\n",
lmp->lm_name, r->r_address, sym);
if (mprotect( lmp->lm_addr + LM_TXTADDR(lmp),
LD_TEXTSZ(lmp->lm_ld),
PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
perror("mprotect"),
fatal("Cannot enable writes to %s\n", lmp->lm_name);
}
lmp->lm_rwt = 1;
}
static struct nzlist *
lookup(name, src_map)
char *name;
struct link_map **src_map;
{
long common_size = 0;
struct link_map *lmp;
struct rt_symbol *rtsp;
*src_map = NULL;
if ((rtsp = lookup_rts(name)) != NULL)
return rtsp->rt_sp;
/*
* Search all maps for a definition of NAME
*/
for (lmp = link_map_head; lmp; lmp = lmp->lm_next) {
int buckets = LD_BUCKETS(lmp->lm_ld);
long hashval = 0;
struct rrs_hash *hp;
char *cp;
struct nzlist *np;
/*
* Compute bucket in which the symbol might be found.
*/
for (cp = name; *cp; cp++)
hashval = (hashval << 1) + *cp;
hashval = (hashval & 0x7fffffff) % buckets;
hp = LM_HASH(lmp) + hashval;
if (hp->rh_symbolnum == -1)
/* Nothing in this bucket */
continue;
while (hp) {
np = LM_SYMBOL(lmp, hp->rh_symbolnum);
cp = LM_STRINGS(lmp) + np->nz_strx;
if (strcmp(cp, name) == 0)
break;
if (hp->rh_next == 0)
hp = NULL;
else
hp = LM_HASH(lmp) + hp->rh_next;
}
if (hp == NULL)
/* Nothing in this bucket */
continue;
/*
* We have a symbol with the name we're looking for.
*/
if (np->nz_value == 0)
/* It's not a definition */
continue;
if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
/* It's a common, note value and continue search */
if (common_size < np->nz_value)
common_size = np->nz_value;
continue;
}
*src_map = lmp;
return np;
}
if (common_size == 0)
/* Not found */
return NULL;
/*
* It's a common, enter into run-time common symbol table.
*/
rtsp = enter_rts(name, (long)calloc(1, common_size),
N_UNDF + N_EXT, 0, common_size);
#if DEBUG
xprintf("Allocating common: %s size %d at %#x\n", name, common_size, rtsp->rt_sp->nz_value);
#endif
return rtsp->rt_sp;
}
/*
* This routine is called from the jumptable to resolve
* procedure calls to shared objects.
*/
long
binder(jsp)
jmpslot_t *jsp;
{
struct link_map *lmp, *src_map;
long addr;
char *sym;
struct nzlist *np;
int index;
/*
* Find the PLT map that contains JSP.
*/
for (lmp = link_map_head; lmp; lmp = lmp->lm_next) {
if (LM_PLT(lmp) < jsp &&
jsp < LM_PLT(lmp) + LD_PLTSZ(lmp->lm_ld)/sizeof(*jsp))
break;
}
if (lmp == NULL)
fatal("Call to binder from unknown location: %#x\n", jsp);
index = jsp->reloc_index & JMPSLOT_RELOC_MASK;
/* Get the local symbol this jmpslot refers to */
sym = LM_STRINGS(lmp) +
LM_SYMBOL(lmp,RELOC_SYMBOL(&LM_REL(lmp)[index]))->nz_strx;
np = lookup(sym, &src_map);
if (np == NULL)
fatal("Undefined symbol called from %s at %#x",
lmp->lm_name, jsp);
/* Fixup jmpslot so future calls transfer directly to target */
addr = np->nz_value;
if (src_map)
addr += (long)src_map->lm_addr;
md_fix_jmpslot(jsp, (long)jsp, addr);
#if DEBUG
xprintf(" BINDER: %s located at = %#x in %s\n", sym, addr, src_map->lm_name);
#endif
return addr;
}
/*
* Run-time common symbol table.
*/
#define RTC_TABSIZE 57
static struct rt_symbol *rt_symtab[RTC_TABSIZE];
/*
* Compute hash value for run-time symbol table
*/
static int
hash_string(key)
char *key;
{
register char *cp;
register int k;
cp = key;
k = 0;
while (*cp)
k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff;
return k;
}
/*
* Lookup KEY in the run-time common symbol table.
*/
static struct rt_symbol *
lookup_rts(key)
char *key;
{
register int hashval;
register struct rt_symbol *rtsp;
/* Determine which bucket. */
hashval = hash_string(key) % RTC_TABSIZE;
/* Search the bucket. */
for (rtsp = rt_symtab[hashval]; rtsp; rtsp = rtsp->rt_link)
if (strcmp(key, rtsp->rt_sp->nz_name) == 0)
return rtsp;
return NULL;
}
static struct rt_symbol *
enter_rts(name, value, type, srcaddr, size)
char *name;
long value;
int type;
caddr_t srcaddr;
long size;
{
register int hashval;
register struct rt_symbol *rtsp, **rpp;
/* Determine which bucket */
hashval = hash_string(name) % RTC_TABSIZE;
/* Find end of bucket */
for (rpp = &rt_symtab[hashval]; *rpp; rpp = &(*rpp)->rt_link)
;
/* Allocate new common symbol */
rtsp = (struct rt_symbol *)malloc(sizeof(struct rt_symbol));
rtsp->rt_sp = (struct nzlist *)malloc(sizeof(struct nzlist));
rtsp->rt_sp->nz_name = strdup(name);
rtsp->rt_sp->nz_value = value;
rtsp->rt_sp->nz_type = type;
rtsp->rt_sp->nz_size = size;
rtsp->rt_srcaddr = srcaddr;
rtsp->rt_link = NULL;
/* Link onto linear list as well */
rtsp->rt_next = rt_symbol_head;
rt_symbol_head = rtsp;
*rpp = rtsp;
return rtsp;
}
#undef major
#undef minor
static char *
rtfindlib(name, major, minor)
char *name;
{
return (char *)findshlib(name, &major, &minor);
}
static int
dlopen(name, mode)
char *name;
int mode;
{
xprintf("dlopen(%s, %x)\n", name, mode);
return -1;
}
static int
dlclose(fd)
int fd;
{
xprintf("dlclose(%d)\n", fd);
return -1;
}
static int
dlsym(fd, sym)
int fd;
char *sym;
{
xprintf("dlsym(%d, %s)\n", fd, sym);
return 0;
}
/*
* Private heap functions.
*/
static caddr_t curbrk;
static void
init_brk()
{
struct rlimit rlim;
char *cp, **cpp = environ;
getrlimit(RLIMIT_STACK, &rlim);
while (*cpp) cpp++;
cp = *--cpp;
while (*cp) cp++;
curbrk = (caddr_t)
(((long)(cp - 1 - rlim.rlim_cur) + PAGSIZ) & ~(PAGSIZ - 1));
}
xprintf(fmt, a, b, c, d, e, f, g, h, i, j)
char *fmt;
{
char buf[128];
sprintf(buf, fmt, a, b, c, d, e, f, g, h, i, j);
write(1, buf, strlen(buf));
}
caddr_t
sbrk(incr)
int incr;
{
int fd = -1;
caddr_t oldbrk;
if (curbrk == 0)
init_brk();
#if DEBUG
xprintf("sbrk: incr = %#x, curbrk = %#x\n", incr, curbrk);
#endif
if (incr == 0)
return curbrk;
incr = (incr + PAGSIZ - 1) & ~(PAGSIZ - 1);
#ifdef sun
fd = open("/dev/zero", O_RDWR, 0);
if (fd == -1)
perror("/dev/zero");
#endif
if (mmap(curbrk, incr,
PROT_READ|PROT_WRITE,
MAP_ANON|MAP_FIXED|MAP_COPY, fd, 0) == (caddr_t)-1) {
perror("Cannot map anonymous memory");
}
#ifdef sun
close(fd);
#endif
oldbrk = curbrk;
curbrk += incr;
return oldbrk;
}
Reference in New Issue View Git Blame Copy Permalink