diff options
author | Niklas Hallqvist <niklas@cvs.openbsd.org> | 1996-11-23 04:12:06 +0000 |
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committer | Niklas Hallqvist <niklas@cvs.openbsd.org> | 1996-11-23 04:12:06 +0000 |
commit | 37d4621bd4a912b6a032bc21906f7032e602cbf2 (patch) | |
tree | 6e6f3dad18baebc5f90abdcbbf4a8ba242555627 /gnu/usr.bin/binutils/mmalloc/mmcheck.c | |
parent | fb7c7a778840ea235dd0bb550cfd2e2ac8ccb37c (diff) |
Merge to Cygnus 961112 + add some support (not ready) for shared libs
Diffstat (limited to 'gnu/usr.bin/binutils/mmalloc/mmcheck.c')
-rw-r--r-- | gnu/usr.bin/binutils/mmalloc/mmcheck.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/gnu/usr.bin/binutils/mmalloc/mmcheck.c b/gnu/usr.bin/binutils/mmalloc/mmcheck.c new file mode 100644 index 00000000000..48936b3e630 --- /dev/null +++ b/gnu/usr.bin/binutils/mmalloc/mmcheck.c @@ -0,0 +1,223 @@ +/* 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); +} |