hurd/hurdstartup.c

   1 /* Initial program startup for running under the GNU Hurd.
   2 Copyright (C) 1991, 92, 93, 94, 95, 96 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_startup.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 #include <argz.h>
  34
  35 mach_port_t *_hurd_init_dtable;
  36 mach_msg_type_number_t _hurd_init_dtablesize;
  37
  38 unsigned int __hurd_threadvar_max;
  39 unsigned long int __hurd_threadvar_stack_mask;
  40 unsigned long int __hurd_threadvar_stack_offset;
  41
  42 /* These are set up by _hurdsig_init.  */
  43 unsigned long int __hurd_sigthread_stack_base;
  44 unsigned long int __hurd_sigthread_stack_end;
  45 unsigned long int *__hurd_sigthread_variables;
  46
  47 extern void __mach_init (void);
  48
  49 /* Entry point.  This is the first thing in the text segment.
  50
  51    The exec server started the initial thread in our task with this spot the
  52    PC, and a stack that is presumably big enough.  We do basic Mach
  53    initialization so mig-generated stubs work, and then do an exec_startup
  54    RPC on our bootstrap port, to which the exec server responds with the
  55    information passed in the exec call, as well as our original bootstrap
  56    port, and the base address and size of the preallocated stack.
  57
  58    If using cthreads, we are given a new stack by cthreads initialization and
  59    deallocate the stack set up by the exec server.  On the new stack we call
  60    `start1' (above) to do the rest of the startup work.  Since the stack may
  61    disappear out from under us in a machine-dependent way, we use a pile of
  62    static variables to communicate the information from exec_startup to start1.
  63    This is unfortunate but preferable to machine-dependent frobnication to copy
  64    the state from the old stack to the new one.  */
  65
  66
  67 void
  68 _hurd_startup (void **argptr, void (*main) (int *data))
  69 {
  70   error_t err;
  71   mach_port_t in_bootstrap;
  72   char *args, *env;
  73   mach_msg_type_number_t argslen, envlen;
  74   struct hurd_startup_data data;
  75   char **argv, **envp;
  76   int argc, envc;
  77   int *argcptr;
  78
  79   if (err = __task_get_special_port (__mach_task_self (), TASK_BOOTSTRAP_PORT,
  80                                      &in_bootstrap))
  81     LOSE;
  82
  83   if (in_bootstrap != MACH_PORT_NULL)
  84     {
  85       /* Call the exec server on our bootstrap port and
  86          get all our standard information from it.  */
  87
  88       argslen = envlen = 0;
  89       data.dtablesize = data.portarraysize = data.intarraysize = 0;
  90
  91       err = __exec_startup_get_info (in_bootstrap,
  92                                      &data.user_entry,
  93                                      &data.phdr, &data.phdrsz,
  94                                      &data.stack_base, &data.stack_size,
  95                                      &data.flags,
  96                                      &args, &argslen,
  97                                      &env, &envlen,
  98                                      &data.dtable, &data.dtablesize,
  99                                      &data.portarray, &data.portarraysize,
 100                                      &data.intarray, &data.intarraysize);
 101       __mach_port_deallocate (__mach_task_self (), in_bootstrap);
 102     }
 103
 104   if (err || in_bootstrap == MACH_PORT_NULL || (data.flags & EXEC_STACK_ARGS))
 105     {
 106       /* Either we have no bootstrap port, or the RPC to the exec server
 107          failed, or whoever started us up passed the flag saying args are
 108          on the stack.  Try to snarf the args in the canonical Mach way.
 109          Hopefully either they will be on the stack as expected, or the
 110          stack will be zeros so we don't crash.  */
 111
 112       argcptr = (int *) argptr;
 113       argc = argcptr[0];
 114       argv = (char **) &argcptr[1];
 115       envp = &argv[argc + 1];
 116       envc = 0;
 117       while (envp[envc])
 118         ++envc;
 119     }
 120   else
 121     {
 122       /* Turn the block of null-separated strings we were passed for the
 123          arguments and environment into vectors of pointers to strings.  */
 124
 125       /* Count up the arguments so we can allocate ARGV.  */
 126       argc = __argz_count (args, argslen);
 127       /* Count up the environment variables so we can allocate ENVP.  */
 128       envc = __argz_count (env, envlen);
 129
 130       /* There were some arguments.  Allocate space for the vectors of
 131          pointers and fill them in.  We allocate the space for the
 132          environment pointers immediately after the argv pointers because
 133          the ELF ABI will expect it.  */
 134       argcptr = __alloca (sizeof (int) +
 135                           (argc + 1 + envc + 1) * sizeof (char *) +
 136                           sizeof (struct hurd_startup_data));
 137       *argcptr = argc;
 138       argv = (void *) (argcptr + 1);
 139       __argz_extract (args, argslen, argv);
 140
 141       /* There was some environment.  */
 142       envp = &argv[argc + 1];
 143       __argz_extract (env, envlen, envp);
 144     }
 145
 146   if (err || in_bootstrap == MACH_PORT_NULL)
 147     {
 148       /* Either we have no bootstrap port, or the RPC to the exec server
 149          failed.  Set all our other variables to have empty information.  */
 150
 151       data.flags = 0;
 152       args = env = NULL;
 153       argslen = envlen = 0;
 154       data.dtable = NULL;
 155       data.dtablesize = 0;
 156       data.portarray = NULL;
 157       data.portarraysize = 0;
 158       data.intarray = NULL;
 159       data.intarraysize = 0;
 160     }
 161   else if ((void *) &envp[envc + 1] == argv[0])
 162     {
 163       /* The arguments arrived on the stack from the kernel, but our
 164          protocol requires some space after them for a `struct
 165          hurd_startup_data'.  Move them.  */
 166       struct
 167         {
 168           int count;
 169           char *argv[argc + 1];
 170           char *envp[envc + 1];
 171           struct hurd_startup_data data;
 172         } *args = alloca (sizeof *args);
 173       if ((void *) &args[1] == (void *) argcptr)
 174         args = alloca (-((char *) &args->data - (char *) args));
 175       memmove (args, argcptr, (char *) &args->data - (char *) args);
 176       argcptr = (void *) args;
 177       argv = args->argv;
 178       envp = args->envp;
 179     }
 180
 181   {
 182     struct hurd_startup_data *d = (void *) &envp[envc + 1];
 183
 184     if ((void *) d != argv[0])
 185       {
 186         *d = data;
 187         _hurd_init_dtable = d->dtable;
 188         _hurd_init_dtablesize = d->dtablesize;
 189       }
 190
 191     (*main) (argcptr);
 192   }
 193
 194   /* Should never get here.  */
 195   LOSE;
 196   abort ();
 197 }