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-rw-r--r--mmalloc/mmcheck.c223
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diff --git a/mmalloc/mmcheck.c b/mmalloc/mmcheck.c
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+++ b/mmalloc/mmcheck.c
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+/* Standard debugging hooks for `mmalloc'.
+ Copyright 1990, 1991, 1992 Free Software Foundation
+
+ Written May 1989 by Mike Haertel.
+ Heavily modified Mar 1992 by Fred Fish (fnf@cygnus.com)
+
+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.
+
+ The author may be reached (Email) at the address mike@ai.mit.edu,
+ or (US mail) as Mike Haertel c/o Free Software Foundation. */
+
+#include "mmprivate.h"
+
+/* Default function to call when something awful happens. The application
+ can specify an alternate function to be called instead (and probably will
+ want to). */
+
+extern void abort PARAMS ((void));
+
+/* Arbitrary magical numbers. */
+
+#define MAGICWORD (unsigned int) 0xfedabeeb /* Active chunk */
+#define MAGICWORDFREE (unsigned int) 0xdeadbeef /* Inactive chunk */
+#define MAGICBYTE ((char) 0xd7)
+
+/* Each memory allocation is bounded by a header structure and a trailer
+ byte. I.E.
+
+ <size><magicword><user's allocation><magicbyte>
+
+ The pointer returned to the user points to the first byte in the
+ user's allocation area. The magic word can be tested to detect
+ buffer underruns and the magic byte can be tested to detect overruns. */
+
+struct hdr
+ {
+ size_t size; /* Exact size requested by user. */
+ unsigned long int magic; /* Magic number to check header integrity. */
+ };
+
+static void checkhdr PARAMS ((struct mdesc *, CONST struct hdr *));
+static void mfree_check PARAMS ((PTR, PTR));
+static PTR mmalloc_check PARAMS ((PTR, size_t));
+static PTR mrealloc_check PARAMS ((PTR, PTR, size_t));
+
+/* Check the magicword and magicbyte, and if either is corrupted then
+ call the emergency abort function specified for the heap in use. */
+
+static void
+checkhdr (mdp, hdr)
+ struct mdesc *mdp;
+ CONST struct hdr *hdr;
+{
+ if (hdr -> magic != MAGICWORD ||
+ ((char *) &hdr[1])[hdr -> size] != MAGICBYTE)
+ {
+ (*mdp -> abortfunc)();
+ }
+}
+
+static void
+mfree_check (md, ptr)
+ PTR md;
+ PTR ptr;
+{
+ struct hdr *hdr = ((struct hdr *) ptr) - 1;
+ struct mdesc *mdp;
+
+ mdp = MD_TO_MDP (md);
+ checkhdr (mdp, hdr);
+ hdr -> magic = MAGICWORDFREE;
+ mdp -> mfree_hook = NULL;
+ mfree (md, (PTR)hdr);
+ mdp -> mfree_hook = mfree_check;
+}
+
+static PTR
+mmalloc_check (md, size)
+ PTR md;
+ size_t size;
+{
+ struct hdr *hdr;
+ struct mdesc *mdp;
+ size_t nbytes;
+
+ mdp = MD_TO_MDP (md);
+ mdp -> mmalloc_hook = NULL;
+ nbytes = sizeof (struct hdr) + size + 1;
+ hdr = (struct hdr *) mmalloc (md, nbytes);
+ mdp -> mmalloc_hook = mmalloc_check;
+ if (hdr != NULL)
+ {
+ hdr -> size = size;
+ hdr -> magic = MAGICWORD;
+ hdr++;
+ *((char *) hdr + size) = MAGICBYTE;
+ }
+ return ((PTR) hdr);
+}
+
+static PTR
+mrealloc_check (md, ptr, size)
+ PTR md;
+ PTR ptr;
+ size_t size;
+{
+ struct hdr *hdr = ((struct hdr *) ptr) - 1;
+ struct mdesc *mdp;
+ size_t nbytes;
+
+ mdp = MD_TO_MDP (md);
+ checkhdr (mdp, hdr);
+ mdp -> mfree_hook = NULL;
+ mdp -> mmalloc_hook = NULL;
+ mdp -> mrealloc_hook = NULL;
+ nbytes = sizeof (struct hdr) + size + 1;
+ hdr = (struct hdr *) mrealloc (md, (PTR) hdr, nbytes);
+ mdp -> mfree_hook = mfree_check;
+ mdp -> mmalloc_hook = mmalloc_check;
+ mdp -> mrealloc_hook = mrealloc_check;
+ if (hdr != NULL)
+ {
+ hdr -> size = size;
+ hdr++;
+ *((char *) hdr + size) = MAGICBYTE;
+ }
+ return ((PTR) hdr);
+}
+
+/* Turn on default checking for mmalloc/mrealloc/mfree, for the heap specified
+ by MD. If FUNC is non-NULL, it is a pointer to the function to call
+ to abort whenever memory corruption is detected. By default, this is the
+ standard library function abort().
+
+ Note that we disallow installation of initial checking hooks if mmalloc
+ has been called at any time for this particular heap, since if any region
+ that is allocated prior to installation of the hooks is subsequently
+ reallocated or freed after installation of the hooks, it is guaranteed
+ to trigger a memory corruption error. We do this by checking the state
+ of the MMALLOC_INITIALIZED flag. If the FORCE argument is non-zero, this
+ checking is disabled and it is allowed to install the checking hooks at any
+ time. This is useful on systems where the C runtime makes one or more
+ malloc calls before the user code had a chance to call mmcheck or mmcheckf,
+ but never calls free with these values. Thus if we are certain that only
+ values obtained from mallocs after an mmcheck/mmcheckf will ever be passed
+ to free(), we can go ahead and force installation of the useful checking
+ hooks.
+
+ However, we can call this function at any time after the initial call,
+ to update the function pointers to the checking routines and to the
+ user defined corruption handler routine, as long as these function pointers
+ have been previously extablished by the initial call. Note that we
+ do this automatically when remapping a previously used heap, to ensure
+ that the hooks get updated to the correct values, although the corruption
+ handler pointer gets set back to the default. The application can then
+ call mmcheck to use a different corruption handler if desired.
+
+ Returns non-zero if checking is successfully enabled, zero otherwise. */
+
+int
+mmcheckf (md, func, force)
+ PTR md;
+ void (*func) PARAMS ((void));
+ int force;
+{
+ struct mdesc *mdp;
+ int rtnval;
+
+ mdp = MD_TO_MDP (md);
+
+ /* We can safely set or update the abort function at any time, regardless
+ of whether or not we successfully do anything else. */
+
+ mdp -> abortfunc = (func != NULL ? func : abort);
+
+ /* If we haven't yet called mmalloc the first time for this heap, or if we
+ have hooks that were previously installed, then allow the hooks to be
+ initialized or updated. */
+
+ if (force ||
+ !(mdp -> flags & MMALLOC_INITIALIZED) ||
+ (mdp -> mfree_hook != NULL))
+ {
+ mdp -> mfree_hook = mfree_check;
+ mdp -> mmalloc_hook = mmalloc_check;
+ mdp -> mrealloc_hook = mrealloc_check;
+ mdp -> flags |= MMALLOC_MMCHECK_USED;
+ rtnval = 1;
+ }
+ else
+ {
+ rtnval = 0;
+ }
+
+ return (rtnval);
+}
+
+/* This routine is for backwards compatibility only, in case there are
+ still callers to the original mmcheck function. */
+
+int
+mmcheck (md, func)
+ PTR md;
+ void (*func) PARAMS ((void));
+{
+ int rtnval;
+
+ rtnval = mmcheckf (md, func, 0);
+ return (rtnval);
+}
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