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_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
  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_get_info (in_bootstrap,
  94                                      &data.user_entry,
  95                                      &data.phdr, &data.phdrsz,
  96                                      &data.stack_base, &data.stack_size,
  97                                      &data.flags,
  98                                      &args, &argslen,
  99                                      &env, &envlen,
 100                                      &data.dtable, &data.dtablesize,
 101                                      &data.portarray, &data.portarraysize,
 102                                      &data.intarray, &data.intarraysize);
 103       __mach_port_deallocate (__mach_task_self (), in_bootstrap);
 104     }
 105
 106   if (err || in_bootstrap == MACH_PORT_NULL || (data.flags & EXEC_STACK_ARGS))
 107     {
 108       /* Either we have no bootstrap port, or the RPC to the exec server
 109          failed, or whoever started us up passed the flag saying args are
 110          on the stack.  Try to snarf the args in the canonical Mach way.
 111          Hopefully either they will be on the stack as expected, or the
 112          stack will be zeros so we don't crash.  */
 113
 114       argcptr = (int *) argptr;
 115       argc = argcptr[0];
 116       argv = (char **) &argcptr[1];
 117       envp = &argv[argc + 1];
 118       envc = 0;
 119       while (envp[envc])
 120         ++envc;
 121     }
 122   else
 123     {
 124       /* Turn the block of null-separated strings we were passed for the
 125          arguments and environment into vectors of pointers to strings.  */
 126
 127       /* Count up the arguments so we can allocate ARGV.  */
 128       argc = _hurd_split_args (args, argslen, NULL);
 129       /* Count up the environment variables so we can allocate ENVP.  */
 130       envc = _hurd_split_args (env, envlen, NULL);
 131
 132       /* There were some arguments.  Allocate space for the vectors of
 133          pointers and fill them in.  We allocate the space for the
 134          environment pointers immediately after the argv pointers because
 135          the ELF ABI will expect it.  */
 136       argcptr = __alloca (sizeof (int) +
 137                           (argc + 1 + envc + 1) * sizeof (char *) +
 138                           sizeof (struct hurd_startup_data));
 139       *argcptr = argc;
 140       argv = (void *) (argcptr + 1);
 141       _hurd_split_args (args, argslen, argv);
 142
 143       /* There was some environment.  */
 144       envp = &argv[argc + 1];
 145       _hurd_split_args (env, envlen, envp);
 146     }
 147
 148   if (err || in_bootstrap == MACH_PORT_NULL)
 149     {
 150       /* Either we have no bootstrap port, or the RPC to the exec server
 151          failed.  Set all our other variables to have empty information.  */
 152
 153       data.flags = 0;
 154       args = env = NULL;
 155       argslen = envlen = 0;
 156       data.dtable = NULL;
 157       data.dtablesize = 0;
 158       data.portarray = NULL;
 159       data.portarraysize = 0;
 160       data.intarray = NULL;
 161       data.intarraysize = 0;
 162     }
 163   else if ((void *) &envp[envc + 1] == argv[0])
 164     {
 165       /* The arguments arrived on the stack from the kernel, but our
 166          protocol requires some space after them for a `struct
 167          hurd_startup_data'.  Move them.  */
 168       struct
 169         {
 170           int count;
 171           char *argv[argc + 1];
 172           char *envp[envc + 1];
 173           struct hurd_startup_data data;
 174         } *args = alloca (sizeof *args);
 175       if ((void *) &args[1] == (void *) argcptr)
 176         args = alloca (-((char *) &args->data - (char *) args));
 177       memmove (args, argcptr, (char *) &args->data - (char *) args);
 178       argcptr = (void *) args;
 179       argv = args->argv;
 180       envp = args->envp;
 181     }
 182
 183   {
 184     struct hurd_startup_data *d = (void *) &envp[envc + 1];
 185
 186     if ((void *) d != argv[0])
 187       {
 188         *d = data;
 189         _hurd_init_dtable = d->dtable;
 190         _hurd_init_dtablesize = d->dtablesize;
 191       }
 192
 193     (*main) (argcptr);
 194   }
 195
 196   /* Should never get here.  */
 197   LOSE;
 198   abort ();
 199 }
 200
 201 /* Split ARGSLEN bytes at ARGS into words, breaking at NUL characters.  If
 202    ARGV is not a null pointer, store a pointer to the start of each word in
 203    ARGV[n], and null-terminate ARGV.  Return the number of words split.  */
 204
 205 int
 206 _hurd_split_args (char *args, size_t argslen, char **argv)
 207 {
 208   char *p = args;
 209   size_t n = argslen;
 210   int argc = 0;
 211
 212   while (n > 0)
 213     {
 214       char *end = memchr (p, '\0', n);
 215
 216       if (argv)
 217         argv[argc] = p;
 218       ++argc;
 219
 220       if (end == NULL)
 221         /* The last argument is unterminated.  */
 222         break;
 223
 224       n -= end + 1 - p;
 225       p = end + 1;
 226     }
 227
 228   if (argv)
 229     argv[argc] = NULL;
 230   return argc;
 231 }