/* This testcase is part of GDB, the GNU debugger. Copyright 2004, 2007 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. Please email any bugs, comments, and/or additions to this file to: bug-gdb@prep.ai.mit.edu */ /* Get 64-bit stuff if on a GNU system. */ #define _GNU_SOURCE #include #include #include #include #include #include #include /* Print routines: The following are so that printf et.al. can be avoided. Those might try to use malloc() and that, for this code, would be a disaster. */ #define printf do not use const char digit[] = "0123456789abcdefghijklmnopqrstuvwxyz"; static void print_char (char c) { write (1, &c, sizeof (c)); } static void print_unsigned (unsigned long long u) { if (u >= 10) print_unsigned (u / 10); print_char (digit[u % 10]); } static void print_hex (unsigned long long u) { if (u >= 16) print_hex (u / 16); print_char (digit[u % 16]); } static void print_string (const char *s) { for (; (*s) != '\0'; s++) print_char ((*s)); } static void print_address (const void *a) { print_string ("0x"); print_hex ((unsigned long) a); } static void print_byte_count (unsigned long long u) { print_unsigned (u); print_string (" ("); print_string ("0x"); print_hex (u); print_string (") bytes"); } /* Print the current values of RESOURCE. */ static void print_rlimit (int resource) { struct rlimit rl; getrlimit (resource, &rl); print_string ("cur=0x"); print_hex (rl.rlim_cur); print_string (" max=0x"); print_hex (rl.rlim_max); } static void maximize_rlimit (int resource, const char *prefix) { struct rlimit rl; print_string (" "); print_string (prefix); print_string (": "); print_rlimit (resource); getrlimit (resource, &rl); rl.rlim_cur = rl.rlim_max; setrlimit (resource, &rl); print_string (" -> "); print_rlimit (resource); print_string ("\n"); } /* Maintain a doublely linked list. */ struct list { struct list *next; struct list *prev; size_t size; }; /* Put the "heap" in the DATA section. That way it is more likely that the variable will occur early in the core file (an address before the heap) and hence more likely that GDB will at least get its value right. To simplify the list append logic, start the heap out with one entry (that lives in the BSS section). */ static struct list dummy; static struct list heap = { &dummy, &dummy }; static unsigned long bytes_allocated; #ifdef O_LARGEFILE #define large_off_t off64_t #define large_lseek lseek64 #else #define large_off_t off_t #define O_LARGEFILE 0 #define large_lseek lseek #endif int main () { size_t max_chunk_size; large_off_t max_core_size; /* Try to expand all the resource limits beyond the point of sanity - we're after the biggest possible core file. */ print_string ("Maximize resource limits ...\n"); #ifdef RLIMIT_CORE maximize_rlimit (RLIMIT_CORE, "core"); #endif #ifdef RLIMIT_DATA maximize_rlimit (RLIMIT_DATA, "data"); #endif #ifdef RLIMIT_STACK maximize_rlimit (RLIMIT_STACK, "stack"); #endif #ifdef RLIMIT_AS maximize_rlimit (RLIMIT_AS, "stack"); #endif print_string ("Maximize allocation limits ...\n"); /* Compute the largest possible corefile size. No point in trying to create a corefile larger than the largest file supported by the file system. What about 64-bit lseek64? */ { int fd; large_off_t tmp; unlink ("bigcore.corefile"); fd = open ("bigcore.corefile", O_RDWR | O_CREAT | O_TRUNC | O_LARGEFILE, 0666); for (tmp = 1; tmp > 0; tmp <<= 1) { if (large_lseek (fd, tmp, SEEK_SET) > 0) max_core_size = tmp; } close (fd); } /* Compute an initial chunk size. The math is dodgy but it works for the moment. Perhaphs there's a constant around somewhere. Limit this to max_core_size bytes - no point in trying to allocate more than can be written to the corefile. */ { size_t tmp; for (tmp = 1; tmp > 0 && tmp < max_core_size; tmp <<= 1) max_chunk_size = tmp; } print_string (" core: "); print_byte_count (max_core_size); print_string ("\n"); print_string (" chunk: "); print_byte_count (max_chunk_size); print_string ("\n"); print_string (" large? "); if (O_LARGEFILE) print_string ("yes\n"); else print_string ("no\n"); /* Allocate as much memory as possible creating a linked list of each section. The linking ensures that some, but not all, the memory is allocated. NB: Some kernels handle this efficiently - only allocating and writing out referenced pages leaving holes in the file for unmodified pages - while others handle this poorly - writing out all pages including those that weren't modified. */ print_string ("Alocating the entire heap ...\n"); { size_t chunk_size; unsigned long chunks_allocated = 0; /* Create a linked list of memory chunks. Start with MAX_CHUNK_SIZE blocks of memory and then try allocating smaller and smaller amounts until all (well at least most) memory has been allocated. */ for (chunk_size = max_chunk_size; chunk_size >= sizeof (struct list); chunk_size >>= 1) { unsigned long count = 0; print_string (" "); print_byte_count (chunk_size); print_string (" ... "); while (bytes_allocated + (1 + count) * chunk_size < max_core_size) { struct list *chunk = malloc (chunk_size); if (chunk == NULL) break; chunk->size = chunk_size; /* Link it in. */ chunk->next = NULL; chunk->prev = heap.prev; heap.prev->next = chunk; heap.prev = chunk; count++; } print_unsigned (count); print_string (" chunks\n"); chunks_allocated += count; bytes_allocated += chunk_size * count; } print_string ("Total of "); print_byte_count (bytes_allocated); print_string (" bytes "); print_unsigned (chunks_allocated); print_string (" chunks\n"); } /* Push everything out to disk. */ print_string ("Dump core ....\n"); *(char*)0 = 0; }