1 /* This testcase is part of GDB, the GNU debugger. 2 3 Copyright 2004 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2 of the License, or 8 (at your option) any later version. 9 10 This program 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 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program; if not, write to the Free Software 17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 18 19 Please email any bugs, comments, and/or additions to this file to: 20 bug-gdb@prep.ai.mit.edu */ 21 22 /* Get 64-bit stuff if on a GNU system. */ 23 #define _GNU_SOURCE 24 25 #include <sys/types.h> 26 #include <sys/time.h> 27 #include <sys/resource.h> 28 #include <sys/stat.h> 29 #include <fcntl.h> 30 31 #include <stdlib.h> 32 #include <unistd.h> 33 34 /* Print routines: 35 36 The following are so that printf et.al. can be avoided. Those 37 might try to use malloc() and that, for this code, would be a 38 disaster. */ 39 40 #define printf do not use 41 42 const char digit[] = "0123456789abcdefghijklmnopqrstuvwxyz"; 43 44 static void 45 print_char (char c) 46 { 47 write (1, &c, sizeof (c)); 48 } 49 50 static void 51 print_unsigned (unsigned long long u) 52 { 53 if (u >= 10) 54 print_unsigned (u / 10); 55 print_char (digit[u % 10]); 56 } 57 58 static void 59 print_hex (unsigned long long u) 60 { 61 if (u >= 16) 62 print_hex (u / 16); 63 print_char (digit[u % 16]); 64 } 65 66 static void 67 print_string (const char *s) 68 { 69 for (; (*s) != '\0'; s++) 70 print_char ((*s)); 71 } 72 73 static void 74 print_address (const void *a) 75 { 76 print_string ("0x"); 77 print_hex ((unsigned long) a); 78 } 79 80 static void 81 print_byte_count (unsigned long long u) 82 { 83 print_unsigned (u); 84 print_string (" ("); 85 print_string ("0x"); 86 print_hex (u); 87 print_string (") bytes"); 88 } 89 90 /* Print the current values of RESOURCE. */ 91 92 static void 93 print_rlimit (int resource) 94 { 95 struct rlimit rl; 96 getrlimit (resource, &rl); 97 print_string ("cur=0x"); 98 print_hex (rl.rlim_cur); 99 print_string (" max=0x"); 100 print_hex (rl.rlim_max); 101 } 102 103 static void 104 maximize_rlimit (int resource, const char *prefix) 105 { 106 struct rlimit rl; 107 print_string (" "); 108 print_string (prefix); 109 print_string (": "); 110 print_rlimit (resource); 111 getrlimit (resource, &rl); 112 rl.rlim_cur = rl.rlim_max; 113 setrlimit (resource, &rl); 114 print_string (" -> "); 115 print_rlimit (resource); 116 print_string ("\n"); 117 } 118 119 /* Maintain a doublely linked list. */ 120 struct list 121 { 122 struct list *next; 123 struct list *prev; 124 size_t size; 125 }; 126 127 /* Put the "heap" in the DATA section. That way it is more likely 128 that the variable will occur early in the core file (an address 129 before the heap) and hence more likely that GDB will at least get 130 its value right. 131 132 To simplify the list append logic, start the heap out with one 133 entry (that lives in the BSS section). */ 134 135 static struct list dummy; 136 static struct list heap = { &dummy, &dummy }; 137 138 static unsigned long bytes_allocated; 139 140 #ifdef O_LARGEFILE 141 #define large_off_t off64_t 142 #define large_lseek lseek64 143 #else 144 #define large_off_t off_t 145 #define O_LARGEFILE 0 146 #define large_lseek lseek 147 #endif 148 149 int 150 main () 151 { 152 size_t max_chunk_size; 153 large_off_t max_core_size; 154 155 /* Try to expand all the resource limits beyond the point of sanity 156 - we're after the biggest possible core file. */ 157 158 print_string ("Maximize resource limits ...\n"); 159 #ifdef RLIMIT_CORE 160 maximize_rlimit (RLIMIT_CORE, "core"); 161 #endif 162 #ifdef RLIMIT_DATA 163 maximize_rlimit (RLIMIT_DATA, "data"); 164 #endif 165 #ifdef RLIMIT_STACK 166 maximize_rlimit (RLIMIT_STACK, "stack"); 167 #endif 168 #ifdef RLIMIT_AS 169 maximize_rlimit (RLIMIT_AS, "stack"); 170 #endif 171 172 print_string ("Maximize allocation limits ...\n"); 173 174 /* Compute the largest possible corefile size. No point in trying 175 to create a corefile larger than the largest file supported by 176 the file system. What about 64-bit lseek64? */ 177 { 178 int fd; 179 large_off_t tmp; 180 unlink ("bigcore.corefile"); 181 fd = open ("bigcore.corefile", O_RDWR | O_CREAT | O_TRUNC | O_LARGEFILE); 182 for (tmp = 1; tmp > 0; tmp <<= 1) 183 { 184 if (large_lseek (fd, tmp, SEEK_SET) > 0) 185 max_core_size = tmp; 186 } 187 close (fd); 188 } 189 190 /* Compute an initial chunk size. The math is dodgy but it works 191 for the moment. Perhaphs there's a constant around somewhere. 192 Limit this to max_core_size bytes - no point in trying to 193 allocate more than can be written to the corefile. */ 194 { 195 size_t tmp; 196 for (tmp = 1; tmp > 0 && tmp < max_core_size; tmp <<= 1) 197 max_chunk_size = tmp; 198 } 199 200 print_string (" core: "); 201 print_byte_count (max_core_size); 202 print_string ("\n"); 203 print_string (" chunk: "); 204 print_byte_count (max_chunk_size); 205 print_string ("\n"); 206 print_string (" large? "); 207 if (O_LARGEFILE) 208 print_string ("yes\n"); 209 else 210 print_string ("no\n"); 211 212 /* Allocate as much memory as possible creating a linked list of 213 each section. The linking ensures that some, but not all, the 214 memory is allocated. NB: Some kernels handle this efficiently - 215 only allocating and writing out referenced pages leaving holes in 216 the file for unmodified pages - while others handle this poorly - 217 writing out all pages including those that weren't modified. */ 218 219 print_string ("Alocating the entire heap ...\n"); 220 { 221 size_t chunk_size; 222 unsigned long chunks_allocated = 0; 223 /* Create a linked list of memory chunks. Start with 224 MAX_CHUNK_SIZE blocks of memory and then try allocating smaller 225 and smaller amounts until all (well at least most) memory has 226 been allocated. */ 227 for (chunk_size = max_chunk_size; 228 chunk_size >= sizeof (struct list); 229 chunk_size >>= 1) 230 { 231 unsigned long count = 0; 232 print_string (" "); 233 print_byte_count (chunk_size); 234 print_string (" ... "); 235 while (bytes_allocated + (1 + count) * chunk_size 236 < max_core_size) 237 { 238 struct list *chunk = malloc (chunk_size); 239 if (chunk == NULL) 240 break; 241 chunk->size = chunk_size; 242 /* Link it in. */ 243 chunk->next = NULL; 244 chunk->prev = heap.prev; 245 heap.prev->next = chunk; 246 heap.prev = chunk; 247 count++; 248 } 249 print_unsigned (count); 250 print_string (" chunks\n"); 251 chunks_allocated += count; 252 bytes_allocated += chunk_size * count; 253 } 254 print_string ("Total of "); 255 print_byte_count (bytes_allocated); 256 print_string (" bytes "); 257 print_unsigned (chunks_allocated); 258 print_string (" chunks\n"); 259 } 260 261 /* Push everything out to disk. */ 262 263 print_string ("Dump core ....\n"); 264 *(char*)0 = 0; 265 } 266