malloc/tst-realloc.c

   1 /* Copyright (C) 2013-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <malloc.h>
  20 #include <stdint.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <libc-diag.h>
  24 #include <support/check.h>
  25
  26 static int
  27 do_test (void)
  28 {
  29   void *p;
  30   unsigned char *c;
  31   int save, i, ok;
  32
  33   errno = 0;
  34
  35   /* realloc (NULL, ...) behaves similarly to malloc (C89).  */
  36   DIAG_PUSH_NEEDS_COMMENT;
  37 #if __GNUC_PREREQ (7, 0)
  38   /* GCC 7 warns about too-large allocations; here we want to test
  39      that they fail.  */
  40   DIAG_IGNORE_NEEDS_COMMENT (7, "-Walloc-size-larger-than=");
  41 #endif
  42   p = realloc (NULL, -1);
  43   DIAG_POP_NEEDS_COMMENT;
  44   save = errno;
  45
  46   if (p != NULL)
  47     FAIL_EXIT1 ("realloc (NULL, -1) succeeded.");
  48
  49   /* errno should be set to ENOMEM on failure (POSIX).  */
  50   if (p == NULL && save != ENOMEM)
  51     FAIL_EXIT1 ("errno is not set correctly");
  52
  53   errno = 0;
  54
  55   /* realloc (NULL, ...) behaves similarly to malloc (C89).  */
  56   p = realloc (NULL, 10);
  57   save = errno;
  58
  59   if (p == NULL)
  60     FAIL_EXIT1 ("realloc (NULL, 10) failed.");
  61
  62   free (p);
  63
  64   p = calloc (20, 1);
  65   if (p == NULL)
  66     FAIL_EXIT1 ("calloc (20, 1) failed.");
  67
  68   /* Check increasing size preserves contents (C89).  */
  69   p = realloc (p, 200);
  70   if (p == NULL)
  71     FAIL_EXIT1 ("realloc (p, 200) failed.");
  72
  73   c = p;
  74   ok = 1;
  75
  76   for (i = 0; i < 20; i++)
  77     {
  78       if (c[i] != 0)
  79         ok = 0;
  80     }
  81
  82   if (ok == 0)
  83     FAIL_EXIT1 ("first 20 bytes were not cleared");
  84
  85   free (p);
  86
  87   p = realloc (NULL, 100);
  88   if (p == NULL)
  89     FAIL_EXIT1 ("realloc (NULL, 100) failed.");
  90
  91   memset (p, 0xff, 100);
  92
  93   /* Check decreasing size preserves contents (C89).  */
  94   p = realloc (p, 16);
  95   if (p == NULL)
  96     FAIL_EXIT1 ("realloc (p, 16) failed.");
  97
  98   c = p;
  99   ok = 1;
 100
 101   for (i = 0; i < 16; i++)
 102     {
 103       if (c[i] != 0xff)
 104         ok = 0;
 105     }
 106
 107   if (ok == 0)
 108     FAIL_EXIT1 ("first 16 bytes were not correct");
 109
 110   /* Check failed realloc leaves original untouched (C89).  */
 111   DIAG_PUSH_NEEDS_COMMENT;
 112 #if __GNUC_PREREQ (7, 0)
 113   /* GCC 7 warns about too-large allocations; here we want to test
 114      that they fail.  */
 115   DIAG_IGNORE_NEEDS_COMMENT (7, "-Walloc-size-larger-than=");
 116 #endif
 117   c = realloc (p, -1);
 118   DIAG_POP_NEEDS_COMMENT;
 119   if (c != NULL)
 120     FAIL_EXIT1 ("realloc (p, -1) succeeded.");
 121
 122   c = p;
 123   ok = 1;
 124
 125   for (i = 0; i < 16; i++)
 126     {
 127       if (c[i] != 0xff)
 128         ok = 0;
 129     }
 130
 131   if (ok == 0)
 132     FAIL_EXIT1 ("first 16 bytes were not correct after failed realloc");
 133
 134   /* realloc (p, 0) frees p (C89) and returns NULL (glibc).  */
 135   p = realloc (p, 0);
 136   if (p != NULL)
 137     FAIL_EXIT1 ("realloc (p, 0) returned non-NULL.");
 138
 139   /* realloc (NULL, 0) acts like malloc (0) (glibc).  */
 140   p = realloc (NULL, 0);
 141   if (p == NULL)
 142     FAIL_EXIT1 ("realloc (NULL, 0) returned NULL.");
 143
 144   free (p);
 145
 146   /* Smoke test to make sure that allocations do not move if they have enough
 147      space to expand in the chunk.  */
 148   for (size_t sz = 3; sz < 256 * 1024; sz += 2048)
 149     {
 150       p = realloc (NULL, sz);
 151       if (p == NULL)
 152         FAIL_EXIT1 ("realloc (NULL, %zu) returned NULL.", sz);
 153       size_t newsz = malloc_usable_size (p);
 154       printf ("size: %zu, usable size: %zu, extra: %zu\n",
 155               sz, newsz, newsz - sz);
 156       uintptr_t oldp = (uintptr_t) p;
 157       void *new_p = realloc (p, newsz);
 158       if ((uintptr_t) new_p != oldp)
 159         FAIL_EXIT1 ("Expanding (%zu bytes) to usable size (%zu) moved block",
 160                     sz, newsz);
 161       free (new_p);
 162
 163       /* We encountered a large enough extra size at least once.  */
 164       if (newsz - sz > 1024)
 165         break;
 166     }
 167
 168   return 0;
 169 }
 170
 171 #define TEST_FUNCTION do_test ()
 172 #include "../test-skeleton.c"