645c4be38a
into libc. This reduces the size of every dynamically linked executable by 248 bytes, and it reduces the size of static executables by a lesser amount. It also eliminates some global namespace pollution. With this change in place, the source for dlfcn.h should probably be moved to "/usr/src/include". I'll save that for another day. Compatibility note: Programs which use dlopen, if compiled on systems with this change, will not run on systems with a libc from prior to this change. Very few programs use dlopen, so I think that is OK.
361 lines
8.7 KiB
C
361 lines
8.7 KiB
C
/*
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* Copyright (c) 1993 Paul Kranenburg
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Paul Kranenburg.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $Id: crt0.c,v 1.32 1998/02/06 16:46:33 jdp Exp $
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*/
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#include <sys/param.h>
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#include <stdlib.h>
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#include <dlfcn.h>
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#ifdef DYNAMIC
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#include <sys/types.h>
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#include <sys/syscall.h>
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#include <a.out.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <link.h>
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/* !!!
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* This is gross, ld.so is a ZMAGIC a.out, but has `sizeof(hdr)' for
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* an entry point and not at PAGSIZ as the N_*ADDR macros assume.
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*/
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#undef N_DATADDR
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#define N_DATADDR(x) ((x).a_text)
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#undef N_BSSADDR
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#define N_BSSADDR(x) ((x).a_text + (x).a_data)
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#ifndef N_GETMAGIC
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#define N_GETMAGIC(x) ((x).a_magic)
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#endif /* N_GETMAGIC */
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#ifndef MAP_PRIVATE
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#define MAP_PRIVATE MAP_COPY
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#endif /* MAP_PRIVATE */
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#ifndef MAP_FILE
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#define MAP_FILE 0
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#endif /* MAP_FILE */
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#ifndef MAP_ANON
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#define MAP_ANON 0
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#endif /* MAP_ANON */
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#ifdef DEBUG
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/*
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* We need these two because we are going to call them before the ld.so is
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* finished (as a matter of fact before we know if it exists !) so we must
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* provide these versions for them
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*/
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static char *_getenv();
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static int _strncmp();
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#endif /* DEBUG */
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#ifndef LDSO
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#define LDSO "/usr/libexec/ld.so"
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#endif /* LDSO */
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extern struct _dynamic _DYNAMIC;
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static void __do_dynamic_link(char **argv);
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#endif /* DYNAMIC */
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int _callmain();
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int errno;
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static char empty[1];
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char *__progname = empty;
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char **environ;
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/* Globals used by dlopen() and related functions in libc */
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struct ld_entry *__ldso_entry;
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int __ldso_version;
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extern unsigned char etext;
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extern unsigned char eprol asm ("eprol");
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extern start() asm("start");
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extern mcount() asm ("mcount");
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extern int main(int argc, char **argv, char **envp);
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int __syscall(int syscall,...);
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#ifdef MCRT0
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void monstartup(void *low, void *high);
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#endif /* MCRT0 */
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/*
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* We need these system calls, but can't use library stubs because the are
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* not accessible until we have done the ld.so stunt.
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*/
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#define _exit(v) \
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__syscall(SYS_exit, (int)(v))
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#define _open(name, f, m) \
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__syscall(SYS_open, (char *)(name), (int)(f), (int)(m))
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#define _read(fd, s, n) \
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__syscall(SYS_read, (int)(fd), (void *)(s), (size_t)(n))
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#define _write(fd, s, n) \
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__syscall(SYS_write, (int)(fd), (void *)(s), (size_t)(n))
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#define _mmap(addr, len, prot, flags, fd, off) \
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(caddr_t) __syscall(SYS_mmap, (caddr_t)(addr), (size_t)(len), \
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(int)(prot), (int)(flags), (int)(fd), (long)0L, (off_t)(off))
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#define _PUTNMSG(str, len) _write(2, (str), (len))
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#define _PUTMSG(str) _PUTNMSG((str), sizeof (str) - 1)
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#define _FATAL(str) ( _PUTMSG(str), _exit(1) )
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int
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start()
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{
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struct kframe {
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int kargc;
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char *kargv[1]; /* size depends on kargc */
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char kargstr[1]; /* size varies */
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char kenvstr[1]; /* size varies */
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};
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/*
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* ALL REGISTER VARIABLES!!!
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*/
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register struct kframe *kfp;
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register char **targv;
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register char **argv;
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extern void _mcleanup();
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#ifdef DYNAMIC
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volatile caddr_t x;
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#endif
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#ifdef lint
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kfp = 0;
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#else /* not lint */
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/* just above the saved frame pointer */
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asm ("lea 4(%%ebp), %0" : "=r" (kfp) );
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#endif /* not lint */
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for (argv = targv = &kfp->kargv[0]; *targv++; /* void */)
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/* void */ ;
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if (targv >= (char **)(*argv))
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--targv;
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environ = targv;
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if (argv[0]) {
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register char *s;
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__progname = argv[0];
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for (s=__progname; *s != '\0'; s++)
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if (*s == '/')
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__progname = s+1;
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}
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#ifdef DYNAMIC
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/* ld(1) convention: if DYNAMIC = 0 then statically linked */
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/* sometimes GCC is too smart/stupid for its own good */
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x = (caddr_t)&_DYNAMIC;
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if (x)
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__do_dynamic_link(argv);
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#endif /* DYNAMIC */
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asm("eprol:");
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#ifdef MCRT0
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atexit(_mcleanup);
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monstartup(&eprol, &etext);
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#endif /* MCRT0 */
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asm ("__callmain:"); /* Defined for the benefit of debuggers */
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exit(main(kfp->kargc, argv, environ));
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}
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#ifdef DYNAMIC
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static void
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__do_dynamic_link(argv)
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char **argv;
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{
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struct crt_ldso crt;
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struct exec hdr;
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char *ldso;
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int (*entry)();
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#ifdef DEBUG
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/* Provision for alternate ld.so - security risk! */
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if (!(ldso = _getenv("LDSO")))
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#endif
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ldso = LDSO;
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crt.crt_ldfd = _open(ldso, 0, 0);
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if (crt.crt_ldfd == -1) {
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_PUTMSG("Couldn't open ");
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_PUTMSG(LDSO);
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_FATAL(".\n");
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}
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/* Read LDSO exec header */
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if (_read(crt.crt_ldfd, &hdr, sizeof hdr) < sizeof hdr) {
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_FATAL("Failure reading ld.so\n");
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}
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if ((N_GETMAGIC_NET(hdr) != ZMAGIC) && (N_GETMAGIC(hdr) != QMAGIC)) {
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_FATAL("Bad magic: ld.so\n");
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}
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/* We use MAP_ANON */
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crt.crt_dzfd = -1;
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/* Map in ld.so */
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crt.crt_ba = (int)_mmap(0, hdr.a_text,
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PROT_READ|PROT_EXEC,
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MAP_FILE|MAP_PRIVATE,
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crt.crt_ldfd, N_TXTOFF(hdr));
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if (crt.crt_ba == -1) {
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_FATAL("Cannot map ld.so (text)\n");
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}
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/* Map in data segment of ld.so writable */
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if ((int)_mmap((caddr_t)(crt.crt_ba+N_DATADDR(hdr)), hdr.a_data,
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PROT_READ|PROT_WRITE,
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MAP_FIXED|MAP_FILE|MAP_PRIVATE,
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crt.crt_ldfd, N_DATOFF(hdr)) == -1) {
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_FATAL("Cannot map ld.so (data)\n");
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}
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/* Map bss segment of ld.so zero */
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if (hdr.a_bss && (int)_mmap((caddr_t)(crt.crt_ba+N_BSSADDR(hdr)),
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hdr.a_bss,
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PROT_READ|PROT_WRITE,
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MAP_FIXED|MAP_ANON|MAP_PRIVATE,
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crt.crt_dzfd, 0) == -1) {
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_FATAL("Cannot map ld.so (bss)\n");
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}
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crt.crt_dp = &_DYNAMIC;
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crt.crt_ep = environ;
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crt.crt_bp = (caddr_t)_callmain;
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crt.crt_prog = __progname;
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crt.crt_ldso = ldso;
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crt.crt_ldentry = NULL;
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crt.crt_argv = argv;
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entry = (int (*)())(crt.crt_ba + sizeof hdr);
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__ldso_version = (*entry)(CRT_VERSION_BSD_5, &crt);
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__ldso_entry = crt.crt_ldentry;
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if (__ldso_version == -1 && __ldso_entry == NULL) {
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/* If version 5 not recognised, try version 4 */
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__ldso_version = (*entry)(CRT_VERSION_BSD_4, &crt);
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__ldso_entry = crt.crt_ldentry;
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if (__ldso_version == -1 && __ldso_entry == NULL) {
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/* if version 4 not recognised, try version 3 */
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__ldso_version = (*entry)(CRT_VERSION_BSD_3, &crt);
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__ldso_entry = _DYNAMIC.d_entry;
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}
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}
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if (__ldso_version == -1) {
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_PUTMSG("ld.so failed");
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if (__ldso_entry != NULL) {
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const char *msg = (__ldso_entry->dlerror)();
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if(msg != NULL) {
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const char *endp;
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_PUTMSG(": ");
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for(endp = msg; *endp != '\0'; ++endp)
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; /* Find the end */
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_PUTNMSG(msg, endp - msg);
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}
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}
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_FATAL("\n");
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}
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if (__ldso_version >= LDSO_VERSION_HAS_DLEXIT)
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atexit(__ldso_entry->dlexit);
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return;
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}
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/*
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* Support routines
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*/
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#ifdef DEBUG
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static int
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_strncmp(s1, s2, n)
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register char *s1, *s2;
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register n;
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{
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if (n == 0)
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return (0);
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do {
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if (*s1 != *s2++)
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return (*(unsigned char *)s1 - *(unsigned char *)--s2);
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if (*s1++ == 0)
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break;
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} while (--n != 0);
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return (0);
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}
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static char *
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_getenv(name)
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register char *name;
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{
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extern char **environ;
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register int len;
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register char **P, *C;
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for (C = name, len = 0; *C && *C != '='; ++C, ++len);
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for (P = environ; *P; ++P)
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if (!_strncmp(*P, name, len))
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if (*(C = *P + len) == '=') {
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return(++C);
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}
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return (char *)0;
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}
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#endif /* DEBUG */
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asm(" ___syscall:");
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asm(" popl %ecx");
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asm(" popl %eax");
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asm(" pushl %ecx");
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asm(" .byte 0x9a");
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asm(" .long 0");
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asm(" .word 7");
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asm(" pushl %ecx");
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asm(" jc 1f");
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asm(" ret");
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asm(" 1:");
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asm(" movl $-1,%eax");
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asm(" ret");
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#endif /* DYNAMIC */
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/*
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* Support routines
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*/
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#ifdef MCRT0
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asm (" .text");
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asm ("_eprol:");
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#endif
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