dl-sysdep.c

Glibc 2.3.2源代码(解压后有100多M)

/* Operating system support for run-time dynamic linker.  Hurd version.
   Copyright (C) 1995,96,97,98,99,2000,01,02 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <hurd.h>
#include <link.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <ldsodefs.h>
#include <sys/wait.h>
#include <assert.h>
#include <sysdep.h>
#include <mach/mig_support.h>
#include "hurdstartup.h"
#include <hurd/lookup.h>
#include <hurd/auth.h>
#include <hurd/term.h>
#include <stdarg.h>
#include <ctype.h>
#include <sys/stat.h>
#include <sys/uio.h>

#include <entry.h>
#include <dl-machine.h>
#include <dl-procinfo.h>

extern void __mach_init (void);

extern int _dl_argc;
extern char **_dl_argv;
extern char **_environ;

int __libc_enable_secure = 0;
INTVARDEF(__libc_enable_secure)
int __libc_multiple_libcs = 0;	/* Defining this here avoids the inclusion
				   of init-first.  */
/* This variable containts the lowest stack address ever used.  */
void *__libc_stack_end;

#if HP_TIMING_AVAIL
hp_timing_t _dl_cpuclock_offset;
#endif


struct hurd_startup_data *_dl_hurd_data;

/* This is used only within ld.so, via dl-minimal.c's __errno_location.  */
#undef errno
int errno attribute_hidden;

/* Defining these variables here avoids the inclusion of hurdsig.c.  */
unsigned long int __hurd_sigthread_stack_base;
unsigned long int __hurd_sigthread_stack_end;
unsigned long int *__hurd_sigthread_variables;

/* Defining these variables here avoids the inclusion of init-first.c.
   We need to provide temporary storage for the per-thread variables
   of the main user thread here, since it is used for storing the
   `errno' variable.  Note that this information is lost once we
   relocate the dynamic linker.  */
static unsigned long int threadvars[_HURD_THREADVAR_MAX];
unsigned long int __hurd_threadvar_stack_offset
  = (unsigned long int) &threadvars;
unsigned long int __hurd_threadvar_stack_mask;

#define FMH defined(__i386__)
#if ! FMH
# define fmh()		((void)0)
# define unfmh()	((void)0)
#else
/* XXX loser kludge for vm_map kernel bug */
#undef	ELF_MACHINE_USER_ADDRESS_MASK
#define ELF_MACHINE_USER_ADDRESS_MASK	0
static vm_address_t fmha;
static vm_size_t fmhs;
static void unfmh(void){
__vm_deallocate(__mach_task_self(),fmha,fmhs);}
static void fmh(void) {
    error_t err;int x;mach_port_t p;
    vm_address_t a=0x08000000U,max=VM_MAX_ADDRESS;
    while (!(err=__vm_region(__mach_task_self(),&a,&fmhs,&x,&x,&x,&x,&p,&x))){
      __mach_port_deallocate(__mach_task_self(),p);
      if (a+fmhs>=0x80000000U){
	max=a; break;}
      fmha=a+=fmhs;}
    if (err) assert(err==KERN_NO_SPACE);
    if (!fmha)fmhs=0;else{
    fmhs=max-fmha;
    err = __vm_map (__mach_task_self (),
		    &fmha, fmhs, 0, 0, MACH_PORT_NULL, 0, 1,
		    VM_PROT_NONE, VM_PROT_NONE, VM_INHERIT_COPY);
    assert_perror(err);}
  }
/* XXX loser kludge for vm_map kernel bug */
#endif


ElfW(Addr)
_dl_sysdep_start (void **start_argptr,
		  void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phent,
				   ElfW(Addr) *user_entry))
{
  void go (intptr_t *argdata)
    {
      extern unsigned int _dl_skip_args; /* rtld.c */
      char **p;

      /* Cache the information in various global variables.  */
      _dl_argc = *argdata;
      _dl_argv = 1 + (char **) argdata;
      _environ = &_dl_argv[_dl_argc + 1];
      for (p = _environ; *p++;); /* Skip environ pointers and terminator.  */

      if ((void *) p == _dl_argv[0])
	{
	  static struct hurd_startup_data nodata;
	  _dl_hurd_data = &nodata;
	  nodata.user_entry = (vm_address_t) ENTRY_POINT;
	}
      else
	_dl_hurd_data = (void *) p;

      INTUSE(__libc_enable_secure) = _dl_hurd_data->flags & EXEC_SECURE;

      if (_dl_hurd_data->flags & EXEC_STACK_ARGS &&
	  _dl_hurd_data->user_entry == 0)
	_dl_hurd_data->user_entry = (vm_address_t) ENTRY_POINT;

unfmh();			/* XXX */

#if 0				/* XXX make this work for real someday... */
      if (_dl_hurd_data->user_entry == (vm_address_t) ENTRY_POINT)
	/* We were invoked as a command, not as the program interpreter.
	   The generic ld.so code supports this: it will parse the args
	   as "ld.so PROGRAM [ARGS...]".  For booting the Hurd, we
	   support an additional special syntax:
	     ld.so [-LIBS...] PROGRAM [ARGS...]
	   Each LIBS word consists of "FILENAME=MEMOBJ";
	   for example "-/lib/libc.so=123" says that the contents of
	   /lib/libc.so are found in a memory object whose port name
	   in our task is 123.  */
	while (_dl_argc > 2 && _dl_argv[1][0] == '-' && _dl_argv[1][1] != '-')
	  {
	    char *lastslash, *memobjname, *p;
	    struct link_map *l;
	    mach_port_t memobj;
	    error_t err;

	    ++_dl_skip_args;
	    --_dl_argc;
	    p = _dl_argv++[1] + 1;

	    memobjname = strchr (p, '=');
	    if (! memobjname)
	      _dl_sysdep_fatal ("Bogus library spec: ", p, "\n", NULL);
	    *memobjname++ = '\0';
	    memobj = 0;
	    while (*memobjname != '\0')
	      memobj = (memobj * 10) + (*memobjname++ - '0');

	    /* Add a user reference on the memory object port, so we will
	       still have one after _dl_map_object_from_fd calls our
	       `close'.  */
	    err = __mach_port_mod_refs (__mach_task_self (), memobj,
					MACH_PORT_RIGHT_SEND, +1);
	    assert_perror (err);

	    lastslash = strrchr (p, '/');
	    l = _dl_map_object_from_fd (lastslash ? lastslash + 1 : p,
					memobj, strdup (p), 0);

	    /* Squirrel away the memory object port where it
	       can be retrieved by the program later.  */
	    l->l_info[DT_NULL] = (void *) memobj;
	  }
#endif

      /* Call elf/rtld.c's main program.  It will set everything
	 up and leave us to transfer control to USER_ENTRY.  */
      (*dl_main) ((const ElfW(Phdr) *) _dl_hurd_data->phdr,
		  _dl_hurd_data->phdrsz / sizeof (ElfW(Phdr)),
		  &_dl_hurd_data->user_entry);

      /* The call above might screw a few things up.

	 First of all, if _dl_skip_args is nonzero, we are ignoring
	 the first few arguments.  However, if we have no Hurd startup
	 data, it is the magical convention that ARGV[0] == P.  The
	 startup code in init-first.c will get confused if this is not
	 the case, so we must rearrange things to make it so.  We'll
	 overwrite the origional ARGV[0] at P with ARGV[_dl_skip_args].

	 Secondly, if we need to be secure, it removes some dangerous
	 environment variables.  If we have no Hurd startup date this
	 changes P (since that's the location after the terminating
	 NULL in the list of environment variables).  We do the same
	 thing as in the first case but make sure we recalculate P.
	 If we do have Hurd startup data, we have to move the data
	 such that it starts just after the terminating NULL in the
	 environment list.

	 We use memmove, since the locations might overlap.  */
      if (INTUSE(__libc_enable_secure) || _dl_skip_args)
	{
	  char **newp;

	  for (newp = _environ; *newp++;);

	  if (_dl_argv[-_dl_skip_args] == (char *) p)
	    {
	      if ((char *) newp != _dl_argv[0])
		{
		  assert ((char *) newp < _dl_argv[0]);
		  _dl_argv[0] = memmove ((char *) newp, _dl_argv[0],
					 strlen (_dl_argv[0]) + 1);
		}
	    }
	  else
	    {
	      if ((void *) newp != _dl_hurd_data)
		memmove (newp, _dl_hurd_data, sizeof (*_dl_hurd_data));
	    }
	}

      {
	extern void _dl_start_user (void);
	/* Unwind the stack to ARGDATA and simulate a return from _dl_start
	   to the RTLD_START code which will run the user's entry point.  */
	RETURN_TO (argdata, &_dl_start_user, _dl_hurd_data->user_entry);
      }
    }

  /* Set up so we can do RPCs.  */
  __mach_init ();

  /* Initialize frequently used global variable.  */
  GL(dl_pagesize) = __getpagesize ();

#if HP_TIMING_AVAIL
  HP_TIMING_NOW (_dl_cpuclock_offset);
#endif

fmh();				/* XXX */

  /* See hurd/hurdstartup.c; this deals with getting information
     from the exec server and slicing up the arguments.
     Then it will call `go', above.  */
  _hurd_startup (start_argptr, &go);

  LOSE;
  abort ();
}

void
internal_function
_dl_sysdep_start_cleanup (void)
{
  /* Deallocate the reply port and task port rights acquired by
     __mach_init.  We are done with them now, and the user will
     reacquire them for himself when he wants them.  */
  __mig_dealloc_reply_port (MACH_PORT_NULL);
  __mach_port_deallocate (__mach_task_self (), __mach_task_self_);
}

/* Minimal open/close/mmap implementation sufficient for initial loading of
   shared libraries.  These are weak definitions so that when the
   dynamic linker re-relocates itself to be user-visible (for -ldl),
   it will get the user's definition (i.e. usually libc's).  */

/* Open FILE_NAME and return a Hurd I/O for it in *PORT, or return an
   error.  If STAT is non-zero, stat the file into that stat buffer.  */
static error_t
open_file (const char *file_name, int flags,
	   mach_port_t *port, struct stat64 *stat)
{
  enum retry_type doretry;
  char retryname[1024];		/* XXX string_t LOSES! */
  file_t startdir;
  error_t err;

  error_t use_init_port (int which, error_t (*operate) (file_t))
    {
      return (which < _dl_hurd_data->portarraysize
	      ? ((*operate) (_dl_hurd_data->portarray[which]))
	      : EGRATUITOUS);
    }
  file_t get_dtable_port (int fd)
    {
      if ((unsigned int) fd < _dl_hurd_data->dtablesize
	  && _dl_hurd_data->dtable[fd] != MACH_PORT_NULL)
	{
	  __mach_port_mod_refs (__mach_task_self (), _dl_hurd_data->dtable[fd],
				MACH_PORT_RIGHT_SEND, +1);
	  return _dl_hurd_data->dtable[fd];
	}
      errno = EBADF;
      return MACH_PORT_NULL;
    }

  assert (!(flags & ~O_READ));

  startdir = _dl_hurd_data->portarray[file_name[0] == '/' ?
				      INIT_PORT_CRDIR : INIT_PORT_CWDIR];

  while (file_name[0] == '/')
    file_name++;

  err = __dir_lookup (startdir, (char *)file_name, O_RDONLY, 0,
		      &doretry, retryname, port);

  if (!err)
    err = __hurd_file_name_lookup_retry (use_init_port, get_dtable_port,
					 __dir_lookup, doretry, retryname,
					 O_RDONLY, 0, port);
  if (!err && stat)
    {