271 lines
7 KiB
C
271 lines
7 KiB
C
/* This testcase is part of GDB, the GNU debugger.
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Copyright 2004-2016 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Get 64-bit stuff if on a GNU system. */
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#define _GNU_SOURCE
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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/* This test was written for >2GB core files on 32-bit systems. On
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current 64-bit systems, generating a >4EB (2 ** 63) core file is
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not practical, and getting as close as we can takes a lot of
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useless CPU time. So limit ourselves to a bit bigger than
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32-bit, which is still a useful test. */
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#define RLIMIT_CAP (1ULL << 34)
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/* Print routines:
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The following are so that printf et.al. can be avoided. Those
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might try to use malloc() and that, for this code, would be a
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disaster. */
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#define printf do not use
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const char digit[] = "0123456789abcdefghijklmnopqrstuvwxyz";
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static void
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print_char (char c)
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{
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write (1, &c, sizeof (c));
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}
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static void
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print_unsigned (unsigned long long u)
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{
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if (u >= 10)
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print_unsigned (u / 10);
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print_char (digit[u % 10]);
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}
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static void
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print_hex (unsigned long long u)
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{
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if (u >= 16)
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print_hex (u / 16);
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print_char (digit[u % 16]);
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}
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static void
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print_string (const char *s)
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{
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for (; (*s) != '\0'; s++)
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print_char ((*s));
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}
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static void
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print_address (const void *a)
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{
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print_string ("0x");
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print_hex ((unsigned long) a);
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}
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static void
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print_byte_count (unsigned long long u)
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{
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print_unsigned (u);
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print_string (" (");
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print_string ("0x");
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print_hex (u);
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print_string (") bytes");
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}
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/* Print the current values of RESOURCE. */
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static void
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print_rlimit (int resource)
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{
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struct rlimit rl;
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getrlimit (resource, &rl);
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print_string ("cur=0x");
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print_hex (rl.rlim_cur);
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print_string (" max=0x");
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print_hex (rl.rlim_max);
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}
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static void
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maximize_rlimit (int resource, const char *prefix)
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{
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struct rlimit rl;
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print_string (" ");
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print_string (prefix);
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print_string (": ");
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print_rlimit (resource);
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getrlimit (resource, &rl);
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rl.rlim_cur = rl.rlim_max;
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if (sizeof (rl.rlim_cur) >= sizeof (RLIMIT_CAP))
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rl.rlim_cur = (rlim_t) RLIMIT_CAP;
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setrlimit (resource, &rl);
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print_string (" -> ");
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print_rlimit (resource);
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print_string ("\n");
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}
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/* Maintain a doublely linked list. */
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struct list
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{
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struct list *next;
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struct list *prev;
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size_t size;
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};
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/* Put the "heap" in the DATA section. That way it is more likely
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that the variable will occur early in the core file (an address
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before the heap) and hence more likely that GDB will at least get
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its value right.
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To simplify the list append logic, start the heap out with one
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entry (that lives in the BSS section). */
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static struct list dummy;
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static struct list heap = { &dummy, &dummy };
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static unsigned long bytes_allocated;
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#ifdef O_LARGEFILE
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#define large_off_t off64_t
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#define large_lseek lseek64
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#else
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#define large_off_t off_t
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#define O_LARGEFILE 0
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#define large_lseek lseek
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#endif
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int
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main ()
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{
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size_t max_chunk_size;
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large_off_t max_core_size;
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/* Try to expand all the resource limits beyond the point of sanity
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- we're after the biggest possible core file. */
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print_string ("Maximize resource limits ...\n");
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#ifdef RLIMIT_CORE
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maximize_rlimit (RLIMIT_CORE, "core");
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#endif
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#ifdef RLIMIT_DATA
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maximize_rlimit (RLIMIT_DATA, "data");
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#endif
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#ifdef RLIMIT_STACK
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maximize_rlimit (RLIMIT_STACK, "stack");
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#endif
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#ifdef RLIMIT_AS
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maximize_rlimit (RLIMIT_AS, "stack");
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#endif
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print_string ("Maximize allocation limits ...\n");
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/* Compute the largest possible corefile size. No point in trying
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to create a corefile larger than the largest file supported by
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the file system. What about 64-bit lseek64? */
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{
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int fd;
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large_off_t tmp;
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unlink ("bigcore.corefile");
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fd = open ("bigcore.corefile", O_RDWR | O_CREAT | O_TRUNC | O_LARGEFILE,
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0666);
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for (tmp = 1; tmp > 0; tmp <<= 1)
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{
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if (large_lseek (fd, tmp, SEEK_SET) > 0)
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max_core_size = tmp;
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}
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close (fd);
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}
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/* Compute an initial chunk size. The math is dodgy but it works
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for the moment. Perhaphs there's a constant around somewhere.
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Limit this to max_core_size bytes - no point in trying to
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allocate more than can be written to the corefile. */
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{
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size_t tmp;
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for (tmp = 1; tmp > 0 && tmp < max_core_size; tmp <<= 1)
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max_chunk_size = tmp;
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}
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print_string (" core: ");
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print_byte_count (max_core_size);
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print_string ("\n");
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print_string (" chunk: ");
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print_byte_count (max_chunk_size);
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print_string ("\n");
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print_string (" large? ");
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if (O_LARGEFILE)
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print_string ("yes\n");
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else
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print_string ("no\n");
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/* Allocate as much memory as possible creating a linked list of
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each section. The linking ensures that some, but not all, the
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memory is allocated. NB: Some kernels handle this efficiently -
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only allocating and writing out referenced pages leaving holes in
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the file for unmodified pages - while others handle this poorly -
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writing out all pages including those that weren't modified. */
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print_string ("Alocating the entire heap ...\n");
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{
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size_t chunk_size;
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unsigned long chunks_allocated = 0;
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/* Create a linked list of memory chunks. Start with
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MAX_CHUNK_SIZE blocks of memory and then try allocating smaller
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and smaller amounts until all (well at least most) memory has
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been allocated. */
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for (chunk_size = max_chunk_size;
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chunk_size >= sizeof (struct list);
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chunk_size >>= 1)
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{
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unsigned long count = 0;
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print_string (" ");
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print_byte_count (chunk_size);
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print_string (" ... ");
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while (bytes_allocated + (1 + count) * chunk_size
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< max_core_size)
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{
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struct list *chunk = malloc (chunk_size);
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if (chunk == NULL)
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break;
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chunk->size = chunk_size;
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/* Link it in. */
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chunk->next = NULL;
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chunk->prev = heap.prev;
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heap.prev->next = chunk;
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heap.prev = chunk;
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count++;
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}
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print_unsigned (count);
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print_string (" chunks\n");
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chunks_allocated += count;
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bytes_allocated += chunk_size * count;
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}
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print_string ("Total of ");
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print_byte_count (bytes_allocated);
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print_string (" bytes ");
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print_unsigned (chunks_allocated);
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print_string (" chunks\n");
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}
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/* Push everything out to disk. */
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print_string ("Dump core ....\n");
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*(char*)0 = 0;
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}
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