lib/csu/i386/crt1.c

   1 /*-
   2  * Copyright 1996-1998 John D. Polstra.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  *
  25  * $FreeBSD: src/lib/csu/i386-elf/crt1.c,v 1.4.2.2 2002/11/18 04:57:13 bde Exp $
  26  * $DragonFly: src/lib/csu/i386/crt1.c,v 1.3 2005/05/11 19:46:51 dillon Exp $
  27  */
  28
  29 #ifndef __GNUC__
  30 #error "GCC is needed to compile this file"
  31 #endif
  32
  33 #include <machine/tls.h>
  34 #include <stddef.h>
  35 #include <stdlib.h>
  36 #include "crtbrand.c"
  37
  38 typedef void (*fptr)(void);
  39
  40 extern void _fini(void);
  41 extern void _init(void);
  42 extern int main(int, char **, char **);
  43
  44 #ifdef GCRT
  45 extern void _mcleanup(void);
  46 extern void monstartup(void *, void *);
  47 extern int eprol;
  48 extern int etext;
  49 #endif
  50
  51 extern int _DYNAMIC;
  52 #pragma weak _DYNAMIC
  53
  54 #ifdef __i386__
  55 #define get_rtld_cleanup()                              \
  56     ({ fptr __value;                                    \
  57        __asm__("movl %%edx,%0" : "=rm"(__value));       \
  58        __value; })
  59 #else
  60 #error "This file only supports the i386 architecture"
  61 #endif
  62
  63 char **environ;
  64 char *__progname = "";
  65
  66 void
  67 _start(char *arguments, ...)
  68 {
  69     fptr rtld_cleanup;
  70     int argc;
  71     char **argv;
  72     char **env;
  73
  74     rtld_cleanup = get_rtld_cleanup();
  75     argv = &arguments;
  76     argc = * (int *) (argv - 1);
  77     env = argv + argc + 1;
  78     environ = env;
  79     if(argc > 0 && argv[0] != NULL) {
  80         char *s;
  81         __progname = argv[0];
  82         for (s = __progname; *s != '\0'; s++)
  83             if (*s == '/')
  84                 __progname = s + 1;
  85     }
  86
  87     /*
  88      * Setup the initial TLS space.  The RTLD does not set up our TLS
  89      * (it can't, it doesn't know how our errno is declared).  It simply
  90      * does all the groundwork required so that we can call
  91      * _rtld_allocate_tls().
  92      */
  93     _init_tls();
  94     _rtld_call_init();
  95
  96     if(&_DYNAMIC != NULL)
  97         atexit(rtld_cleanup);
  98
  99 #ifdef GCRT
 100     atexit(_mcleanup);
 101 #endif
 102     atexit(_fini);
 103 #ifdef GCRT
 104     monstartup(&eprol, &etext);
 105 #endif
 106     _init();
 107 #ifndef __GNUC__
 108     exit( main(argc, argv, env) );
 109 #else
 110         /*
 111          * Some versions of gcc-2 expect the stack frame to be aligned as
 112          * follows after it is set up in main():
 113          *
 114          *  +--------------+ <--- aligned by PREFERRED_STACK_BOUNDARY
 115          *  +%ebp (if any) +
 116          *  +--------------+
 117          *  |return address|
 118          *  +--------------+
 119          *  |  arguments   |
 120          *  |      :       |
 121          *  |      :       |
 122          *  +--------------+
 123          *
 124          * We implement the above to fix just the usual case in FreeBSD-4.
 125          * Alignment for main() is too compiler-dependent to handle correctly
 126          * in all cases here (or in the kernel).  E.g., a different alignment
 127          * is required for at least gcc-2.95.4 even for the small variation
 128          * of compiling main() with -fomit-frame-pointer.
 129          */
 130         __asm__("\n"
 131         "andl   $~0xf, %%esp            # align stack to 16-byte boundary\n"
 132         "subl   $12+12, %%esp           # space for args and padding\n"
 133         "movl   %0, 0(%%esp)\n"
 134         "movl   %1, 4(%%esp)\n"
 135         "movl   %2, 8(%%esp)\n"
 136         "call   main\n"
 137         "movl   %%eax, 0(%%esp)\n"
 138         "call   exit\n"
 139         : : "r" (argc), "r" (argv), "r" (env) : "ax", "cx", "dx", "memory");
 140 #endif
 141 }
 142
 143 #ifdef GCRT
 144 __asm__(".text");
 145 __asm__("eprol:");
 146 __asm__(".previous");
 147 #endif