about summary refs log tree commit diff
path: root/elf/dl-minimal.c
blob: 12d38c9a3a983831250cf08956219df9fb229479 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/* Minimal replacements for basic facilities used in the dynamic linker.
   Copyright (C) 1995, 1996, 1997 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

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

#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
#include <assert.h>
#include <string.h>
#include <link.h>
#include "../stdio-common/_itoa.h"

/* Minimal `malloc' allocator for use while loading shared libraries.
   Only small blocks are allocated, and none are ever freed.  */

static void *alloc_ptr, *alloc_end, *alloc_last_block;

void * weak_function
malloc (size_t n)
{
#ifdef MAP_ANON
#define	_dl_zerofd (-1)
#else
  extern int _dl_zerofd;

  if (_dl_zerofd == -1)
    _dl_zerofd = _dl_sysdep_open_zero_fill ();
#define MAP_ANON 0
#endif

  if (_dl_pagesize == 0)
    _dl_pagesize = __getpagesize ();

  if (alloc_end == 0)
    {
      /* Consume any unused space in the last page of our data segment.  */
      extern int _end;
      alloc_ptr = &_end;
      alloc_end = (void *) 0 + (((alloc_ptr - (void *) 0) + _dl_pagesize - 1)
				& ~(_dl_pagesize - 1));
    }

  /* Make sure the allocation pointer is ideally aligned.  */
  alloc_ptr = (void *) 0 + (((alloc_ptr - (void *) 0) + sizeof (double) - 1)
			    & ~(sizeof (double) - 1));

  if (alloc_ptr + n >= alloc_end)
    {
      /* Insufficient space left; allocate another page.  */
      caddr_t page;
      assert (n <= _dl_pagesize);
      page = __mmap (0, _dl_pagesize, PROT_READ|PROT_WRITE,
		     MAP_ANON|MAP_PRIVATE, _dl_zerofd, 0);
      assert (page != (caddr_t) -1);
      if (page != alloc_end)
	alloc_ptr = page;
      alloc_end = page + _dl_pagesize;
    }

  alloc_last_block = (void *) alloc_ptr;
  alloc_ptr += n;
  return alloc_last_block;
}

/* We use this function occasionally since the real implementation may
   be optimized when it can assume the memory it returns already is
   set to NUL.  */
void * weak_function
calloc (size_t nmemb, size_t size)
{
  size_t total = nmemb * size;
  void *result = malloc (total);
  return memset (result, '\0', total);
}

/* This will rarely be called.  */
void weak_function
free (void *ptr)
{
  /* We can free only the last block allocated.  */
  if (ptr == alloc_last_block)
    alloc_ptr = alloc_last_block;
}

/* This is only called with the most recent block returned by malloc.  */
void * weak_function
realloc (void *ptr, size_t n)
{
  void *new;
  assert (ptr == alloc_last_block);
  alloc_ptr = alloc_last_block;
  new = malloc (n);
  assert (new == ptr);
  return new;
}

/* Avoid signal frobnication in setjmp/longjmp.  Keeps things smaller.  */

#include <setjmp.h>

int weak_function
__sigjmp_save (sigjmp_buf env, int savemask)
{ env[0].__mask_was_saved = savemask; return 0; }

void weak_function
longjmp (jmp_buf env, int val) { __longjmp (env[0].__jmpbuf, val); }

/* Define our own stub for the localization function used by strerror.
   English-only in the dynamic linker keeps it smaller.  */

char * weak_function
__dcgettext (const char *domainname, const char *msgid, int category)
{
  assert (domainname == _libc_intl_domainname);
  return (char *) msgid;
}
weak_alias (__dcgettext, dcgettext)

#ifndef NDEBUG

/* Define (weakly) our own assert failure function which doesn't use stdio.
   If we are linked into the user program (-ldl), the normal __assert_fail
   defn can override this one.  */

void weak_function
__assert_fail (const char *assertion,
	       const char *file, unsigned int line, const char *function)
{
  char buf[64];
  buf[sizeof buf - 1] = '\0';
  _dl_sysdep_fatal ("BUG IN DYNAMIC LINKER ld.so: ",
		    file, ": ", _itoa (line, buf + sizeof buf - 1, 10, 0),
		    ": ", function ?: "", function ? ": " : "",
		    "Assertion `", assertion, "' failed!\n",
		    NULL);

}

void weak_function
__assert_perror_fail (int errnum,
		      const char *file, unsigned int line,
		      const char *function)
{
  char buf[64];
  buf[sizeof buf - 1] = '\0';
  _dl_sysdep_fatal ("BUG IN DYNAMIC LINKER ld.so: ",
		    file, ": ", _itoa (line, buf + sizeof buf - 1, 10, 0),
		    ": ", function ?: "", function ? ": " : "",
		    "Unexpected error: ", strerror (errnum), "\n", NULL);

}

#endif