hurd/hurdstartup.c

   1 /* Initial program startup for running under the GNU Hurd.
   2 Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   3 This file is part of the GNU C Library.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 The GNU C Library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #include <errno.h>
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <hurd.h>
  25 #include <hurd/exec.h>
  26 #include <sysdep.h>
  27 #include <hurd/threadvar.h>
  28 #include <unistd.h>
  29 #include <elf.h>
  30 #include "set-hooks.h"
  31 #include "hurdmalloc.h"         /* XXX */
  32 #include "hurdstartup.h"
  33
  34 mach_port_t *_hurd_init_dtable;
  35 mach_msg_type_number_t _hurd_init_dtablesize;
  36
  37 unsigned int __hurd_threadvar_max;
  38 unsigned long int __hurd_threadvar_stack_mask;
  39 unsigned long int __hurd_threadvar_stack_offset;
  40
  41 /* These are set up by _hurdsig_init.  */
  42 unsigned long int __hurd_sigthread_stack_base;
  43 unsigned long int __hurd_sigthread_stack_end;
  44 unsigned long int *__hurd_sigthread_variables;
  45
  46 extern void __mach_init (void);
  47
  48 int _hurd_split_args (char *, size_t, char **);
  49
  50
  51 /* Entry point.  This is the first thing in the text segment.
  52
  53    The exec server started the initial thread in our task with this spot the
  54    PC, and a stack that is presumably big enough.  We do basic Mach
  55    initialization so mig-generated stubs work, and then do an exec_startup
  56    RPC on our bootstrap port, to which the exec server responds with the
  57    information passed in the exec call, as well as our original bootstrap
  58    port, and the base address and size of the preallocated stack.
  59
  60    If using cthreads, we are given a new stack by cthreads initialization and
  61    deallocate the stack set up by the exec server.  On the new stack we call
  62    `start1' (above) to do the rest of the startup work.  Since the stack may
  63    disappear out from under us in a machine-dependent way, we use a pile of
  64    static variables to communicate the information from exec_startup to start1.
  65    This is unfortunate but preferable to machine-dependent frobnication to copy
  66    the state from the old stack to the new one.  */
  67
  68
  69 void
  70 _hurd_startup (void **argptr, void (*main) (int *data))
  71 {
  72   error_t err;
  73   mach_port_t in_bootstrap;
  74   char *args, *env;
  75   mach_msg_type_number_t argslen, envlen;
  76   struct hurd_startup_data data;
  77   char **argv, **envp;
  78   int argc, envc;
  79   int *argcptr;
  80
  81   if (err = __task_get_special_port (__mach_task_self (), TASK_BOOTSTRAP_PORT,
  82                                      &in_bootstrap))
  83     LOSE;
  84
  85   if (in_bootstrap != MACH_PORT_NULL)
  86     {
  87       /* Call the exec server on our bootstrap port and
  88          get all our standard information from it.  */
  89
  90       argslen = envlen = 0;
  91       data.dtablesize = data.portarraysize = data.intarraysize = 0;
  92
  93       err = __exec_startup (in_bootstrap,
  94                             &data.stack_base, &data.stack_size,
  95                             &data.flags, &args, &argslen, &env, &envlen,
  96                             &data.dtable, &data.dtablesize,
  97                             &data.portarray, &data.portarraysize,
  98                             &data.intarray, &data.intarraysize);
  99       __mach_port_deallocate (__mach_task_self (), in_bootstrap);
 100     }
 101
 102   if (err || in_bootstrap == MACH_PORT_NULL)
 103     {
 104       /* Either we have no bootstrap port, or the RPC to the exec server
 105          failed.  Try to snarf the args in the canonical Mach way.
 106          Hopefully either they will be on the stack as expected, or the
 107          stack will be zeros so we don't crash.  Set all our other
 108          variables to have empty information.  */
 109
 110       argcptr = (int *) argptr;
 111       argc = argcptr[0];
 112       argv = (char **) &argcptr[1];
 113       envp = &argv[argc + 1];
 114       envc = 0;
 115       while (envp[envc])
 116         ++envc;
 117
 118       data.flags = 0;
 119       args = env = NULL;
 120       argslen = envlen = 0;
 121       data.dtable = NULL;
 122       data.dtablesize = 0;
 123       data.portarray = NULL;
 124       data.portarraysize = 0;
 125       data.intarray = NULL;
 126       data.intarraysize = 0;
 127     }
 128   else
 129     argv = envp = NULL;
 130
 131
 132   /* Turn the block of null-separated strings we were passed for the
 133      arguments and environment into vectors of pointers to strings.  */
 134
 135   if (! argv)
 136     {
 137       /* Count up the arguments so we can allocate ARGV.  */
 138       argc = _hurd_split_args (args, argslen, NULL);
 139       /* Count up the environment variables so we can allocate ENVP.  */
 140       envc = _hurd_split_args (env, envlen, NULL);
 141
 142       /* There were some arguments.  Allocate space for the vectors of
 143          pointers and fill them in.  We allocate the space for the
 144          environment pointers immediately after the argv pointers because
 145          the ELF ABI will expect it.  */
 146       argcptr = __alloca (sizeof (int) +
 147                           (argc + 1 + envc + 1) * sizeof (char *) +
 148                           sizeof (struct hurd_startup_data));
 149       *argcptr = argc;
 150       argv = (void *) (argcptr + 1);
 151       _hurd_split_args (args, argslen, argv);
 152
 153       /* There was some environment.  */
 154       envp = &argv[argc + 1];
 155       _hurd_split_args (env, envlen, envp);
 156     }
 157
 158   {
 159     struct hurd_startup_data *d = (void *) &envp[envc + 1];
 160
 161     if ((void *) d != argv[0])
 162       {
 163         *d = data;
 164         _hurd_init_dtable = d->dtable;
 165         _hurd_init_dtablesize = d->dtablesize;
 166
 167     /* XXX hardcoded kludge until exec_startup changes */
 168         {
 169           extern void _start();
 170           vm_address_t page = 0;
 171           vm_size_t size = 0;
 172           if (__vm_read (__mach_task_self (),
 173                          0x08000000, __vm_page_size, &page, &size) == 0)
 174             {
 175               const Elf32_Ehdr *ehdr = (const void *) 0x08000000;
 176               d->phdr = 0x08000000 + ehdr->e_phoff;
 177               d->phdrsz = ehdr->e_phnum * ehdr->e_phentsize;
 178               d->user_entry = ehdr->e_entry;
 179               __vm_deallocate (__mach_task_self (), page, size);
 180             }
 181           else
 182             d->user_entry = (Elf32_Addr) &_start;
 183         }
 184       }
 185
 186     (*main) (argcptr);
 187   }
 188
 189   /* Should never get here.  */
 190   LOSE;
 191   abort ();
 192 }
 193
 194 /* Split ARGSLEN bytes at ARGS into words, breaking at NUL characters.  If
 195    ARGV is not a null pointer, store a pointer to the start of each word in
 196    ARGV[n], and null-terminate ARGV.  Return the number of words split.  */
 197
 198 int
 199 _hurd_split_args (char *args, size_t argslen, char **argv)
 200 {
 201   char *p = args;
 202   size_t n = argslen;
 203   int argc = 0;
 204
 205   while (n > 0)
 206     {
 207       char *end = memchr (p, '\0', n);
 208
 209       if (argv)
 210         argv[argc] = p;
 211       ++argc;
 212
 213       if (end == NULL)
 214         /* The last argument is unterminated.  */
 215         break;
 216
 217       n -= end + 1 - p;
 218       p = end + 1;
 219     }
 220
 221   if (argv)
 222     argv[argc] = NULL;
 223   return argc;
 224 }