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Import the ELF dynamic linker. This is the ElfKit version with

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quite a few enhancements and bug fixes.  There are still some known
deficiencies, but it should be adequate to get us started with ELF.

Submitted by:	John Polstra <jdp@polstra.com>
This commit is contained in:
John Polstra 1998-03-07 19:24:35 +00:00
parent 32dcb97f3e
commit 3124c3e093
10 changed files with 2486 additions and 0 deletions
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libexec/rtld-elf/Makefile Normal file
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#
# $Id: Makefile,v 1.5 1998/03/05 21:05:47 jdp Exp $
#
PROG= ld-elf.so.1
SRCS= rtld_start.S rtld.c map_object.c malloc.c xmalloc.c debug.c
NOMAN= true
CFLAGS+= -elf -fpic
CFLAGS+= -Wall
LDFLAGS+= -elf -nostdlib -Wl,-Bshareable,-Bsymbolic
LDADD+= -lc_pic
.PATH: ${.CURDIR}/${MACHINE}
.include <bsd.prog.mk>

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libexec/rtld-elf/amd64/rtld_start.S Normal file
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/*-
* Copyright 1996-1998 John D. Polstra.
* 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 ``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_start.S,v 1.6 1998/03/05 21:05:53 jdp Exp $
*/
.text
.align 4
.globl .rtld_start
.type .rtld_start,@function
.rtld_start:
xorl %ebp,%ebp # Clear frame pointer for good form
movl %esp,%eax # Save initial stack pointer
subl $4,%esp # A place to store exit procedure addr
pushl %esp # Pass its address to rtld
pushl %eax # Pass initial stack pointer to rtld
call _rtld@PLT # Call rtld(sp); returns entry point
addl $8,%esp # Remove arguments from stack
popl %edx # Get exit procedure address
/*
* At this point, %eax contains the entry point of the main program, and
* %edx contains a pointer to a termination function that should be
* registered with atexit(). (crt1.o registers it.)
*/
.globl .rtld_goto_main
.rtld_goto_main: # This symbol exists just to make debugging easier.
jmp *%eax # Enter main program
/*
* Binder entry point. Control is transferred to here by code in the PLT.
* On entry, there are two arguments on the stack. In ascending address
* order, they are (1) "obj", a pointer to the calling object's Obj_Entry,
* and (2) "reloff", the byte offset of the appropriate relocation entry
* in the PLT relocation table.
*
* We are careful to preserve all registers, even the the caller-save
* registers. That is because this code may be invoked by low-level
* assembly-language code that is not ABI-compliant.
*/
.align 4
.globl _rtld_bind_start
.type _rtld_bind_start,@function
_rtld_bind_start:
pushf # Save eflags
pushl %eax # Save %eax
pushl %edx # Save %edx
pushl %ecx # Save %ecx
pushl 20(%esp) # Copy reloff argument
pushl 20(%esp) # Copy obj argument
call _rtld_bind@PLT # Transfer control to the binder
/* Now %eax contains the entry point of the function being called. */
addl $8,%esp # Discard binder arguments
movl %eax,20(%esp) # Store target over obj argument
popl %ecx # Restore %ecx
popl %edx # Restore %edx
popl %eax # Restore %eax
popf # Restore eflags
leal 4(%esp),%esp # Discard reloff, do not change eflags
ret # "Return" to target address

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/*-
* Copyright 1996-1998 John D. Polstra.
* 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 ``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: debug.c,v 1.1 1998/03/05 21:05:48 jdp Exp $
*/
/*
* Support for printing debugging messages.
*/
#include <stdarg.h>
#include <stdio.h>
#include "debug.h"
int debug = 0;
void
debug_printf(const char *format, ...)
{
if (debug) {
va_list ap;
va_start(ap, format);
fflush(stdout);
vfprintf(stderr, format, ap);
putc('\n', stderr);
va_end(ap);
}
}

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libexec/rtld-elf/debug.h Normal file
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/*-
* Copyright 1996-1998 John D. Polstra.
* 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 ``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: debug.h,v 1.1 1998/03/05 21:05:49 jdp Exp $
*/
/*
* Support for printing debugging messages.
*/
#ifndef DEBUG_H
#define DEBUG_H 1
#ifndef __GNUC__
#error "This file must be compiled with GCC"
#endif
extern void debug_printf(const char *, ...);
extern int debug;
#ifdef DEBUG
#define dbg(format, args...) debug_printf(format , ## args)
#else
#define dbg(format, args...) ((void) 0)
#endif
#endif /* DEBUG_H */

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libexec/rtld-elf/i386/rtld_start.S Normal file
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/*-
* Copyright 1996-1998 John D. Polstra.
* 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 ``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_start.S,v 1.6 1998/03/05 21:05:53 jdp Exp $
*/
.text
.align 4
.globl .rtld_start
.type .rtld_start,@function
.rtld_start:
xorl %ebp,%ebp # Clear frame pointer for good form
movl %esp,%eax # Save initial stack pointer
subl $4,%esp # A place to store exit procedure addr
pushl %esp # Pass its address to rtld
pushl %eax # Pass initial stack pointer to rtld
call _rtld@PLT # Call rtld(sp); returns entry point
addl $8,%esp # Remove arguments from stack
popl %edx # Get exit procedure address
/*
* At this point, %eax contains the entry point of the main program, and
* %edx contains a pointer to a termination function that should be
* registered with atexit(). (crt1.o registers it.)
*/
.globl .rtld_goto_main
.rtld_goto_main: # This symbol exists just to make debugging easier.
jmp *%eax # Enter main program
/*
* Binder entry point. Control is transferred to here by code in the PLT.
* On entry, there are two arguments on the stack. In ascending address
* order, they are (1) "obj", a pointer to the calling object's Obj_Entry,
* and (2) "reloff", the byte offset of the appropriate relocation entry
* in the PLT relocation table.
*
* We are careful to preserve all registers, even the the caller-save
* registers. That is because this code may be invoked by low-level
* assembly-language code that is not ABI-compliant.
*/
.align 4
.globl _rtld_bind_start
.type _rtld_bind_start,@function
_rtld_bind_start:
pushf # Save eflags
pushl %eax # Save %eax
pushl %edx # Save %edx
pushl %ecx # Save %ecx
pushl 20(%esp) # Copy reloff argument
pushl 20(%esp) # Copy obj argument
call _rtld_bind@PLT # Transfer control to the binder
/* Now %eax contains the entry point of the function being called. */
addl $8,%esp # Discard binder arguments
movl %eax,20(%esp) # Store target over obj argument
popl %ecx # Restore %ecx
popl %edx # Restore %edx
popl %eax # Restore %eax
popf # Restore eflags
leal 4(%esp),%esp # Discard reloff, do not change eflags
ret # "Return" to target address

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/*-
* Copyright (c) 1983 Regents of the University of California.
* 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 the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
/*static char *sccsid = "from: @(#)malloc.c 5.11 (Berkeley) 2/23/91";*/
static char *rcsid = "$Id: malloc.c,v 1.2 1996/01/19 18:36:54 jdp Exp $";
#endif /* LIBC_SCCS and not lint */
/*
* malloc.c (Caltech) 2/21/82
* Chris Kingsley, kingsley@cit-20.
*
* This is a very fast storage allocator. It allocates blocks of a small
* number of different sizes, and keeps free lists of each size. Blocks that
* don't exactly fit are passed up to the next larger size. In this
* implementation, the available sizes are 2^n-4 (or 2^n-10) bytes long.
* This is designed for use in a virtual memory environment.
*/
#include <sys/types.h>
#include <err.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/mman.h>
#ifndef BSD
#define MAP_COPY MAP_PRIVATE
#define MAP_FILE 0
#define MAP_ANON 0
#endif
#ifndef BSD /* Need do better than this */
#define NEED_DEV_ZERO 1
#endif
#define NULL 0
static void morecore();
static int findbucket();
/*
* Pre-allocate mmap'ed pages
*/
#define NPOOLPAGES (32*1024/pagesz)
static caddr_t pagepool_start, pagepool_end;
static int morepages();
/*
* The overhead on a block is at least 4 bytes. When free, this space
* contains a pointer to the next free block, and the bottom two bits must
* be zero. When in use, the first byte is set to MAGIC, and the second
* byte is the size index. The remaining bytes are for alignment.
* If range checking is enabled then a second word holds the size of the
* requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
* The order of elements is critical: ov_magic must overlay the low order
* bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
*/
union overhead {
union overhead *ov_next; /* when free */
struct {
u_char ovu_magic; /* magic number */
u_char ovu_index; /* bucket # */
#ifdef RCHECK
u_short ovu_rmagic; /* range magic number */
u_int ovu_size; /* actual block size */
#endif
} ovu;
#define ov_magic ovu.ovu_magic
#define ov_index ovu.ovu_index
#define ov_rmagic ovu.ovu_rmagic
#define ov_size ovu.ovu_size
};
#define MAGIC 0xef /* magic # on accounting info */
#define RMAGIC 0x5555 /* magic # on range info */
#ifdef RCHECK
#define RSLOP sizeof (u_short)
#else
#define RSLOP 0
#endif
/*
* nextf[i] is the pointer to the next free block of size 2^(i+3). The
* smallest allocatable block is 8 bytes. The overhead information
* precedes the data area returned to the user.
*/
#define NBUCKETS 30
static union overhead *nextf[NBUCKETS];
extern char *sbrk();
static int pagesz; /* page size */
static int pagebucket; /* page size bucket */
#ifdef MSTATS
/*
* nmalloc[i] is the difference between the number of mallocs and frees
* for a given block size.
*/
static u_int nmalloc[NBUCKETS];
#include <stdio.h>
#endif
#if defined(MALLOC_DEBUG) || defined(RCHECK)
#define ASSERT(p) if (!(p)) botch("p")
#include <stdio.h>
static void
botch(s)
char *s;
{
fprintf(stderr, "\r\nassertion botched: %s\r\n", s);
(void) fflush(stderr); /* just in case user buffered it */
abort();
}
#else
#define ASSERT(p)
#endif
/* Debugging stuff */
extern void xprintf(const char *, ...);
#define TRACE() xprintf("TRACE %s:%d\n", __FILE__, __LINE__)
void *
malloc(nbytes)
size_t nbytes;
{
register union overhead *op;
register int bucket, n;
register unsigned amt;
/*
* First time malloc is called, setup page size and
* align break pointer so all data will be page aligned.
*/
if (pagesz == 0) {
pagesz = n = getpagesize();
if (morepages(NPOOLPAGES) == 0)
return NULL;
op = (union overhead *)(pagepool_start);
n = n - sizeof (*op) - ((int)op & (n - 1));
if (n < 0)
n += pagesz;
if (n) {
pagepool_start += n;
}
bucket = 0;
amt = 8;
while (pagesz > amt) {
amt <<= 1;
bucket++;
}
pagebucket = bucket;
}
/*
* Convert amount of memory requested into closest block size
* stored in hash buckets which satisfies request.
* Account for space used per block for accounting.
*/
if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
#ifndef RCHECK
amt = 8; /* size of first bucket */
bucket = 0;
#else
amt = 16; /* size of first bucket */
bucket = 1;
#endif
n = -(sizeof (*op) + RSLOP);
} else {
amt = pagesz;
bucket = pagebucket;
}
while (nbytes > amt + n) {
amt <<= 1;
if (amt == 0)
return (NULL);
bucket++;
}
/*
* If nothing in hash bucket right now,
* request more memory from the system.
*/
if ((op = nextf[bucket]) == NULL) {
morecore(bucket);
if ((op = nextf[bucket]) == NULL)
return (NULL);
}
/* remove from linked list */
nextf[bucket] = op->ov_next;
op->ov_magic = MAGIC;
op->ov_index = bucket;
#ifdef MSTATS
nmalloc[bucket]++;
#endif
#ifdef RCHECK
/*
* Record allocated size of block and
* bound space with magic numbers.
*/
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
op->ov_rmagic = RMAGIC;
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
#endif
return ((char *)(op + 1));
}
/*
* Allocate more memory to the indicated bucket.
*/
static void
morecore(bucket)
int bucket;
{
register union overhead *op;
register int sz; /* size of desired block */
int amt; /* amount to allocate */
int nblks; /* how many blocks we get */
/*
* sbrk_size <= 0 only for big, FLUFFY, requests (about
* 2^30 bytes on a VAX, I think) or for a negative arg.
*/
sz = 1 << (bucket + 3);
#ifdef MALLOC_DEBUG
ASSERT(sz > 0);
#else
if (sz <= 0)
return;
#endif
if (sz < pagesz) {
amt = pagesz;
nblks = amt / sz;
} else {
amt = sz + pagesz;
nblks = 1;
}
if (amt > pagepool_end - pagepool_start)
if (morepages(amt/pagesz + NPOOLPAGES) == 0)
return;
op = (union overhead *)pagepool_start;
pagepool_start += amt;
/*
* Add new memory allocated to that on
* free list for this hash bucket.
*/
nextf[bucket] = op;
while (--nblks > 0) {
op->ov_next = (union overhead *)((caddr_t)op + sz);
op = (union overhead *)((caddr_t)op + sz);
}
}
void
free(cp)
void *cp;
{
register int size;
register union overhead *op;
if (cp == NULL)
return;
op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
#ifdef MALLOC_DEBUG
ASSERT(op->ov_magic == MAGIC); /* make sure it was in use */
#else
if (op->ov_magic != MAGIC)
return; /* sanity */
#endif
#ifdef RCHECK
ASSERT(op->ov_rmagic == RMAGIC);
ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
#endif
size = op->ov_index;
ASSERT(size < NBUCKETS);
op->ov_next = nextf[size]; /* also clobbers ov_magic */
nextf[size] = op;
#ifdef MSTATS
nmalloc[size]--;
#endif
}
/*
* When a program attempts "storage compaction" as mentioned in the
* old malloc man page, it realloc's an already freed block. Usually
* this is the last block it freed; occasionally it might be farther
* back. We have to search all the free lists for the block in order
* to determine its bucket: 1st we make one pass thru the lists
* checking only the first block in each; if that fails we search
* ``realloc_srchlen'' blocks in each list for a match (the variable
* is extern so the caller can modify it). If that fails we just copy
* however many bytes was given to realloc() and hope it's not huge.
*/
int realloc_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */
void *
realloc(cp, nbytes)
void *cp;
size_t nbytes;
{
register u_int onb;
register int i;
union overhead *op;
char *res;
int was_alloced = 0;
if (cp == NULL)
return (malloc(nbytes));
op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
if (op->ov_magic == MAGIC) {
was_alloced++;
i = op->ov_index;
} else {
/*
* Already free, doing "compaction".
*
* Search for the old block of memory on the
* free list. First, check the most common
* case (last element free'd), then (this failing)
* the last ``realloc_srchlen'' items free'd.
* If all lookups fail, then assume the size of
* the memory block being realloc'd is the
* largest possible (so that all "nbytes" of new
* memory are copied into). Note that this could cause
* a memory fault if the old area was tiny, and the moon
* is gibbous. However, that is very unlikely.
*/
if ((i = findbucket(op, 1)) < 0 &&
(i = findbucket(op, realloc_srchlen)) < 0)
i = NBUCKETS;
}
onb = 1 << (i + 3);
if (onb < pagesz)
onb -= sizeof (*op) + RSLOP;
else
onb += pagesz - sizeof (*op) - RSLOP;
/* avoid the copy if same size block */
if (was_alloced) {
if (i) {
i = 1 << (i + 2);
if (i < pagesz)
i -= sizeof (*op) + RSLOP;
else
i += pagesz - sizeof (*op) - RSLOP;
}
if (nbytes <= onb && nbytes > i) {
#ifdef RCHECK
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
#endif
return(cp);
} else
free(cp);
}
if ((res = malloc(nbytes)) == NULL)
return (NULL);
if (cp != res) /* common optimization if "compacting" */
bcopy(cp, res, (nbytes < onb) ? nbytes : onb);
return (res);
}
/*
* Search ``srchlen'' elements of each free list for a block whose
* header starts at ``freep''. If srchlen is -1 search the whole list.
* Return bucket number, or -1 if not found.
*/
static int
findbucket(freep, srchlen)
union overhead *freep;
int srchlen;
{
register union overhead *p;
register int i, j;
for (i = 0; i < NBUCKETS; i++) {
j = 0;
for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
if (p == freep)
return (i);
j++;
}
}
return (-1);
}
#ifdef MSTATS
/*
* mstats - print out statistics about malloc
*
* Prints two lines of numbers, one showing the length of the free list
* for each size category, the second showing the number of mallocs -
* frees for each size category.
*/
mstats(s)
char *s;
{
register int i, j;
register union overhead *p;
int totfree = 0,
totused = 0;
fprintf(stderr, "Memory allocation statistics %s\nfree:\t", s);
for (i = 0; i < NBUCKETS; i++) {
for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
;
fprintf(stderr, " %d", j);
totfree += j * (1 << (i + 3));
}
fprintf(stderr, "\nused:\t");
for (i = 0; i < NBUCKETS; i++) {
fprintf(stderr, " %d", nmalloc[i]);
totused += nmalloc[i] * (1 << (i + 3));
}
fprintf(stderr, "\n\tTotal in use: %d, total free: %d\n",
totused, totfree);
}
#endif
static int
morepages(n)
int n;
{
int fd = -1;
int offset;
#ifdef NEED_DEV_ZERO
fd = open("/dev/zero", O_RDWR, 0);
if (fd == -1)
perror("/dev/zero");
#endif
if (pagepool_end - pagepool_start > pagesz) {
caddr_t addr = (caddr_t)
(((int)pagepool_start + pagesz - 1) & ~(pagesz - 1));
if (munmap(addr, pagepool_end - addr) != 0)
warn("morepages: munmap %p", addr);
}
offset = (int)pagepool_start - ((int)pagepool_start & ~(pagesz - 1));
if ((pagepool_start = mmap(0, n * pagesz,
PROT_READ|PROT_WRITE,
MAP_ANON|MAP_COPY, fd, 0)) == (caddr_t)-1) {
xprintf("Cannot map anonymous memory");
return 0;
}
pagepool_end = pagepool_start + n * pagesz;
pagepool_start += offset;
#ifdef NEED_DEV_ZERO
close(fd);
#endif
return n;
}

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/*-
* Copyright 1996-1998 John D. Polstra.
* 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 ``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: map_object.c,v 1.2 1998/03/06 22:14:53 jdp Exp $
*/
#include <sys/param.h>
#include <sys/mman.h>
#include <assert.h>
#include <errno.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>
#include "rtld.h"
static int protflags(int); /* Elf flags -> mmap protection */
/*
* Map a shared object into memory. The argument is a file descriptor,
* which must be open on the object and positioned at its beginning.
*
* The return value is a pointer to a newly-allocated Obj_Entry structure
* for the shared object. Returns NULL on failure.
*/
Obj_Entry *
map_object(int fd)
{
Obj_Entry *obj;
union {
Elf32_Ehdr hdr;
char buf[PAGE_SIZE];
} u;
int nbytes;
Elf32_Phdr *phdr;
Elf32_Phdr *phlimit;
Elf32_Phdr *segs[2];
int nsegs;
Elf32_Phdr *phdyn;
Elf32_Phdr *phphdr;
caddr_t mapbase;
size_t mapsize;
Elf32_Off base_offset;
Elf32_Addr base_vaddr;
Elf32_Addr base_vlimit;
caddr_t base_addr;
Elf32_Off data_offset;
Elf32_Addr data_vaddr;
Elf32_Addr data_vlimit;
caddr_t data_addr;
Elf32_Addr clear_vaddr;
caddr_t clear_addr;
size_t nclear;
Elf32_Addr bss_vaddr;
Elf32_Addr bss_vlimit;
caddr_t bss_addr;
if ((nbytes = read(fd, u.buf, PAGE_SIZE)) == -1) {
_rtld_error("Read error: %s", strerror(errno));
return NULL;
}
/* Make sure the file is valid */
if (nbytes < sizeof(Elf32_Ehdr)
|| u.hdr.e_ident[EI_MAG0] != ELFMAG0
|| u.hdr.e_ident[EI_MAG1] != ELFMAG1
|| u.hdr.e_ident[EI_MAG2] != ELFMAG2
|| u.hdr.e_ident[EI_MAG3] != ELFMAG3) {
_rtld_error("Invalid file format");
return NULL;
}
if (u.hdr.e_ident[EI_CLASS] != ELFCLASS32
|| u.hdr.e_ident[EI_DATA] != ELFDATA2LSB) {
_rtld_error("Unsupported file layout");
return NULL;
}
if (u.hdr.e_ident[EI_VERSION] != EV_CURRENT
|| u.hdr.e_version != EV_CURRENT) {
_rtld_error("Unsupported file version");
return NULL;
}
if (u.hdr.e_type != ET_EXEC && u.hdr.e_type != ET_DYN) {
_rtld_error("Unsupported file type");
return NULL;
}
if (u.hdr.e_machine != EM_386) {
_rtld_error("Unsupported machine");
return NULL;
}
/*
* We rely on the program header being in the first page. This is
* not strictly required by the ABI specification, but it seems to
* always true in practice. And, it simplifies things considerably.
*/
assert(u.hdr.e_phentsize == sizeof(Elf32_Phdr));
assert(u.hdr.e_phoff + u.hdr.e_phnum*sizeof(Elf32_Phdr) <= PAGE_SIZE);
assert(u.hdr.e_phoff + u.hdr.e_phnum*sizeof(Elf32_Phdr) <= nbytes);
/*
* Scan the program header entries, and save key information.
*
* We rely on there being exactly two load segments, text and data,
* in that order.
*/
phdr = (Elf32_Phdr *) (u.buf + u.hdr.e_phoff);
phlimit = phdr + u.hdr.e_phnum;
nsegs = 0;
phdyn = NULL;
phphdr = NULL;
while (phdr < phlimit) {
switch (phdr->p_type) {
case PT_LOAD:
assert(nsegs < 2);
segs[nsegs] = phdr;
++nsegs;
break;
case PT_PHDR:
phphdr = phdr;
break;
case PT_DYNAMIC:
phdyn = phdr;
break;
}
++phdr;
}
if (phdyn == NULL) {
_rtld_error("Object is not dynamically-linked");
return NULL;
}
assert(nsegs == 2);
assert(segs[0]->p_align <= PAGE_SIZE);
assert(segs[1]->p_align <= PAGE_SIZE);
/*
* Map the entire address space of the object, to stake out our
* contiguous region, and to establish the base address for relocation.
*/
base_offset = trunc_page(segs[0]->p_offset);
base_vaddr = trunc_page(segs[0]->p_vaddr);
base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
mapsize = base_vlimit - base_vaddr;
base_addr = u.hdr.e_type == ET_EXEC ? (caddr_t) base_vaddr : NULL;
mapbase = mmap(base_addr, mapsize, protflags(segs[0]->p_flags),
MAP_PRIVATE, fd, base_offset);
if (mapbase == (caddr_t) -1) {
_rtld_error("mmap of entire address space failed: %s",
strerror(errno));
return NULL;
}
if (base_addr != NULL && mapbase != base_addr) {
_rtld_error("mmap returned wrong address: wanted %p, got %p",
base_addr, mapbase);
munmap(mapbase, mapsize);
return NULL;
}
/* Overlay the data segment onto the proper region. */
data_offset = trunc_page(segs[1]->p_offset);
data_vaddr = trunc_page(segs[1]->p_vaddr);
data_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_filesz);
data_addr = mapbase + (data_vaddr - base_vaddr);
if (mmap(data_addr, data_vlimit - data_vaddr, protflags(segs[1]->p_flags),
MAP_PRIVATE|MAP_FIXED, fd, data_offset) == (caddr_t) -1) {
_rtld_error("mmap of data failed: %s", strerror(errno));
return NULL;
}
/* Clear any BSS in the last page of the data segment. */
clear_vaddr = segs[1]->p_vaddr + segs[1]->p_filesz;
clear_addr = mapbase + (clear_vaddr - base_vaddr);
if ((nclear = data_vlimit - clear_vaddr) > 0)
memset(clear_addr, 0, nclear);
/* Overlay the BSS segment onto the proper region. */
bss_vaddr = data_vlimit;
bss_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
bss_addr = mapbase + (bss_vaddr - base_vaddr);
if (bss_vlimit > bss_vaddr) { /* There is something to do */
if (mmap(bss_addr, bss_vlimit - bss_vaddr, protflags(segs[1]->p_flags),
MAP_PRIVATE|MAP_FIXED|MAP_ANON, -1, 0) == (caddr_t) -1) {
_rtld_error("mmap of bss failed: %s", strerror(errno));
return NULL;
}
}
obj = CNEW(Obj_Entry);
obj->mapbase = mapbase;
obj->mapsize = mapsize;
obj->textsize = round_page(segs[0]->p_vaddr + segs[0]->p_memsz) -
base_vaddr;
obj->vaddrbase = base_vaddr;
obj->relocbase = mapbase - base_vaddr;
obj->dynamic = (const Elf32_Dyn *)
(mapbase + (phdyn->p_vaddr - base_vaddr));
if (u.hdr.e_entry != 0)
obj->entry = (caddr_t) (mapbase + (u.hdr.e_entry - base_vaddr));
if (phphdr != NULL) {
obj->phdr = (const Elf32_Phdr *)
(mapbase + (phphdr->p_vaddr - base_vaddr));
obj->phsize = phphdr->p_memsz;
}
return obj;
}
/*
* Given a set of ELF protection flags, return the corresponding protection
* flags for MMAP.
*/
static int
protflags(int elfflags)
{
int prot = 0;
if (elfflags & PF_R)
prot |= PROT_READ;
if (elfflags & PF_W)
prot |= PROT_WRITE;
if (elfflags & PF_X)
prot |= PROT_EXEC;
return prot;
}

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/*-
* Copyright 1996-1998 John D. Polstra.
* 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 ``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.h,v 1.3 1998/03/06 14:00:09 jdp Exp $
*/
#ifndef RTLD_H /* { */
#define RTLD_H 1
#include <sys/types.h>
#include <elf.h>
#include <stddef.h>
#ifndef STANDARD_LIBRARY_PATH
#define STANDARD_LIBRARY_PATH "/usr/lib/elf:/usr/lib"
#endif
#define NEW(type) ((type *) xmalloc(sizeof(type)))
#define CNEW(type) ((type *) xcalloc(sizeof(type)))
/* We might as well do booleans like C++. */
typedef unsigned char bool;
#define false 0
#define true 1
struct Struct_Obj_Entry;
typedef struct Struct_Needed_Entry {
struct Struct_Needed_Entry *next;
struct Struct_Obj_Entry *obj;
unsigned long name; /* Offset of name in string table */
} Needed_Entry;
/*
* Shared object descriptor.
*
* Items marked with "(%)" are dynamically allocated, and must be freed
* when the structure is destroyed.
*/
typedef struct Struct_Obj_Entry {
/*
* These two items have to be set right for compatibility with the
* original ElfKit crt1.o.
*/
Elf32_Word magic; /* Magic number (sanity check) */
Elf32_Word version; /* Version number of struct format */
struct Struct_Obj_Entry *next;
char *path; /* Pathname of underlying file (%) */
int refcount;
int dl_refcount; /* Number of times loaded by dlopen */
/* These items are computed by map_object() or by digest_phdr(). */
caddr_t mapbase; /* Base address of mapped region */
size_t mapsize; /* Size of mapped region in bytes */
size_t textsize; /* Size of text segment in bytes */
Elf32_Addr vaddrbase; /* Base address in shared object file */
caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
const Elf32_Dyn *dynamic; /* Dynamic section */
caddr_t entry; /* Entry point */
const Elf32_Phdr *phdr; /* Program header if it is mapped, else NULL */
size_t phsize; /* Size of program header in bytes */
/* Items from the dynamic section. */
Elf32_Addr *got; /* GOT table */
const Elf32_Rel *rel; /* Relocation entries */
unsigned long relsize; /* Size in bytes of relocation info */
const Elf32_Rel *pltrel; /* PLT relocation entries */
unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
const Elf32_Sym *symtab; /* Symbol table */
const char *strtab; /* String table */
unsigned long strsize; /* Size in bytes of string table */
const Elf32_Word *buckets; /* Hash table buckets array */
unsigned long nbuckets; /* Number of buckets */
const Elf32_Word *chains; /* Hash table chain array */
unsigned long nchains; /* Number of chains */
const char *rpath; /* Search path specified in object */
Needed_Entry *needed; /* Shared objects needed by this one (%) */
void (*init)(void); /* Initialization function to call */
void (*fini)(void); /* Termination function to call */
bool mainprog; /* True if this is the main program */
bool rtld; /* True if this is the dynamic linker */
bool textrel; /* True if there are relocations to text seg */
bool symbolic; /* True if generated with "-Bsymbolic" */
} Obj_Entry;
#define RTLD_MAGIC 0xd550b87a
#define RTLD_VERSION 1
extern void _rtld_error(const char *, ...);
extern Obj_Entry *map_object(int);
extern void *xcalloc(size_t);
extern void *xmalloc(size_t);
extern char *xstrdup(const char *);
#endif /* } */

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/*-
* Copyright 1996-1998 John D. Polstra.
* 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 ``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: xmalloc.c,v 1.1 1998/03/05 21:05:54 jdp Exp $
*/
#include <err.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
void *xmalloc(size_t);
void *
xcalloc(size_t size)
{
return memset(xmalloc(size), 0, size);
}
void *
xmalloc(size_t size)
{
void *p = malloc(size);
if (p == NULL)
err(1, "Out of memory");
return p;
}
char *
xstrdup(const char *s)
{
char *p = strdup(s);
if (p == NULL)
err(1, "Out of memory");
return p;
}