Mercurial > hg > xemacs-beta
view src/free-hook.c @ 315:5e87bc5b1ee4
Added tag r21-0b55 for changeset 341dac730539
author | cvs |
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date | Mon, 13 Aug 2007 10:44:26 +0200 |
parents | c5d627a313b1 |
children | fbbf69b4e8a7 |
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/* This file is part of XEmacs. XEmacs 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, or (at your option) any later version. XEmacs 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 XEmacs; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* Synched up with: Not in FSF. */ /* Debugging hooks for malloc. */ /* These hooks work with gmalloc to catch allocation errors. In particular, the following is trapped: * Freeing the same pointer twice. * Trying to free a pointer not returned by malloc. * Trying to realloc a pointer not returned by malloc. In addition, every word of every block freed is set to 0xdeadbeef. This causes many uses of freed storage to be trapped or recognized. When you use this, the storage used by the last FREE_QUEUE_LIMIT calls to free() is not recycled. When you call free for the Nth time, the (N - FREE_QUEUE_LIMIT)'th block is actually recycled. For these last FREE_QUEUE_LIMIT calls to free() a backtrace is saved showing where it was called from. The function find_backtrace() is provided here to be called from GDB with a pointer (such as would be passed to free()) as argument, e.g. (gdb) p/a *find_backtrace (0x234000). If SAVE_ARGS is defined, the first three arguments to each function are saved as well as the return addresses. If UNMAPPED_FREE is defined, instead of setting every word of freed storage to 0xdeadbeef, every call to malloc goes on its own page(s). When free() is called, the block is read and write protected. This is very useful when debugging, since it usually generates a bus error when the deadbeef hack might only cause some garbage to be printed. However, this is too slow for everyday use, since it takes an enormous number of pages. Some other features that would be useful are: * Checking for storage leaks. This could be done by a GC-like facility that would scan the data segment looking for pointers to allocated storage and tell you about those that are no longer referenced. This could be invoked at any time. Another possibility is to report on what allocated storage is still in use when the process is exited. Typically there will be a large amount, so this might not be very useful. */ #if defined (EMACS_BTL) && defined (sun4) && !defined (__lucid) /* currently only works in this configuration */ # define SAVE_STACK #endif #ifdef emacs #ifdef SAVE_STACK #include "cadillac-btl.h" #endif #include <config.h> #include "lisp.h" #else void *malloc (unsigned long); #endif #if !defined(HAVE_LIBMCHECK) #include <stdio.h> #include "hash.h" #ifdef UNMAPPED_FREE #include <sys/mman.h> #include <sys/param.h> #define ROUND_UP_TO_PAGE(i) (((i) + PAGEOFFSET) & PAGEMASK) #endif #include <sys/types.h> /* System function prototypes don't belong in C source files */ /* extern void free (void *); */ c_hashtable pointer_table; extern void (*__free_hook) (void *); extern void *(*__malloc_hook) (unsigned long); static void *check_malloc (unsigned long); typedef void (*fun_ptr) (); #ifdef SAVE_STACK #define FREE_QUEUE_LIMIT 1000 #else /* free_queue is not too useful without backtrace logging */ #define FREE_QUEUE_LIMIT 1 #endif #define TRACE_LIMIT 20 typedef struct { fun_ptr return_pc; #ifdef SAVE_ARGS void *arg[3]; #endif } fun_entry; typedef struct { void *address; unsigned long length; #ifdef SAVE_STACK fun_entry backtrace[TRACE_LIMIT]; #endif } free_queue_entry; free_queue_entry free_queue[FREE_QUEUE_LIMIT]; int current_free; #ifdef SAVE_STACK static void init_frame (FRAME *fptr) { FRAME tmp_frame; #ifdef sparc /* Do the system trap ST_FLUSH_WINDOWS */ asm ("ta 3"); asm ("st %sp, [%i0+0]"); asm ("st %fp, [%i0+4]"); #endif fptr->pc = (char *) init_frame; tmp_frame = *fptr; PREVIOUS_FRAME (tmp_frame); *fptr = tmp_frame; return; } #ifdef SAVE_ARGS static void * frame_arg (FRAME *fptr, int index) { return ((void *) FRAME_ARG(*fptr, index)); } #endif static void save_backtrace (FRAME *current_frame_ptr, fun_entry *table) { int i = 0; #ifdef SAVE_ARGS int j; #endif FRAME current_frame = *current_frame_ptr; /* Get up and out of free() */ PREVIOUS_FRAME (current_frame); /* now do the basic loop adding data until there is no more */ while (PREVIOUS_FRAME (current_frame) && i < TRACE_LIMIT) { table[i].return_pc = (void (*)())FRAME_PC (current_frame); #ifdef SAVE_ARGS for (j = 0; j < 3; j++) table[i].arg[j] = frame_arg (¤t_frame, j); #endif i++; } memset (&table[i], 0, sizeof (fun_entry) * (TRACE_LIMIT - i)); } free_queue_entry * find_backtrace (void *ptr) { int i; for (i = 0; i < FREE_QUEUE_LIMIT; i++) if (free_queue[i].address == ptr) return &free_queue[i]; return 0; } #endif /* SAVE_STACK */ int strict_free_check; static void check_free (void *ptr) { #ifdef SAVE_STACK FRAME start_frame; init_frame (&start_frame); #endif __free_hook = 0; __malloc_hook = 0; if (!pointer_table) pointer_table = make_hashtable (max (100, FREE_QUEUE_LIMIT * 2)); if (ptr != 0) { long size; #ifdef UNMAPPED_FREE unsigned long rounded_up_size; #endif EMACS_INT present = (EMACS_INT) gethash (ptr, pointer_table, (CONST void **) &size); if (!present) { /* This can only happen if you try to free something that didn't come from malloc */ #if !defined(__linux__) /* I originally wrote: "There's really no need to drop core." I have seen the error of my ways. -slb */ if (strict_free_check) abort (); #endif printf("Freeing unmalloc'ed memory at %p\n", ptr); __free_hook = check_free; __malloc_hook = check_malloc; goto end; } if (size < 0) { /* This happens when you free twice */ #if !defined(__linux__) /* See above comment. */ if (strict_free_check) abort (); #endif printf("Freeing %p twice\n", ptr); __free_hook = check_free; __malloc_hook = check_malloc; goto end; } puthash (ptr, (void *)-size, pointer_table); #ifdef UNMAPPED_FREE /* Round up size to an even number of pages. */ rounded_up_size = ROUND_UP_TO_PAGE (size); /* Protect the pages freed from all access */ if (strict_free_check) mprotect (ptr, rounded_up_size, PROT_NONE); #else /* Set every word in the block to 0xdeadbeef */ if (strict_free_check) { unsigned long long_length = (size + (sizeof (long) - 1)) / sizeof (long); unsigned long i; for (i = 0; i < long_length; i++) ((unsigned long *) ptr)[i] = 0xdeadbeef; } #endif free_queue[current_free].address = ptr; free_queue[current_free].length = size; #ifdef SAVE_STACK save_backtrace (&start_frame, free_queue[current_free].backtrace); #endif current_free++; if (current_free >= FREE_QUEUE_LIMIT) current_free = 0; /* Really free this if there's something there */ { void *old = free_queue[current_free].address; if (old) { #ifdef UNMAPPED_FREE unsigned long old_len = free_queue[current_free].length; mprotect (old, old_len, PROT_READ | PROT_WRITE | PROT_EXEC); #endif free (old); remhash (old, pointer_table); } } } __free_hook = check_free; __malloc_hook = check_malloc; end: return; } static void * check_malloc (unsigned long size) { unsigned long rounded_up_size; void *result; __free_hook = 0; __malloc_hook = 0; if (size == 0) { result = 0; goto end; } #ifdef UNMAPPED_FREE /* Round up to an even number of pages. */ rounded_up_size = ROUND_UP_TO_PAGE (size); #else rounded_up_size = size; #endif result = malloc (rounded_up_size); if (!pointer_table) pointer_table = make_hashtable (FREE_QUEUE_LIMIT * 2); puthash (result, (void *)size, pointer_table); __free_hook = check_free; __malloc_hook = check_malloc; end: return result; } extern void *(*__realloc_hook) (void *, unsigned long); #ifdef MIN #undef MIN #endif #define MIN(A, B) ((A) < (B) ? (A) : (B)) /* Don't optimize realloc */ static void * check_realloc (void * ptr, unsigned long size) { EMACS_INT present; unsigned long old_size; void *result = malloc (size); if (!ptr) return result; present = (EMACS_INT) gethash (ptr, pointer_table, (CONST void **) &old_size); if (!present) { /* This can only happen by reallocing a pointer that didn't come from malloc. */ #if !defined(__linux__) /* see comment in check_free(). */ abort (); #endif printf("Realloc'ing unmalloc'ed pointer at %p\n", ptr); } if (result == 0) goto end; memcpy (result, ptr, MIN (size, old_size)); free (ptr); end: return result; } void enable_strict_free_check (void); void enable_strict_free_check (void) { strict_free_check = 1; } void disable_strict_free_check (void); void disable_strict_free_check (void) { strict_free_check = 0; } /* Note: All BLOCK_INPUT stuff removed from this file because it's completely gone in XEmacs */ static void * block_input_malloc (unsigned long size); static void block_input_free (void* ptr) { __free_hook = 0; __malloc_hook = 0; free (ptr); __free_hook = block_input_free; __malloc_hook = block_input_malloc; } static void * block_input_malloc (unsigned long size) { void* result; __free_hook = 0; __malloc_hook = 0; result = malloc (size); __free_hook = block_input_free; __malloc_hook = block_input_malloc; return result; } static void * block_input_realloc (void* ptr, unsigned long size) { void* result; __free_hook = 0; __malloc_hook = 0; __realloc_hook = 0; result = realloc (ptr, size); __free_hook = block_input_free; __malloc_hook = block_input_malloc; __realloc_hook = block_input_realloc; return result; } #ifdef emacs void disable_free_hook (void); void disable_free_hook (void) { __free_hook = block_input_free; __malloc_hook = block_input_malloc; __realloc_hook = block_input_realloc; } void init_free_hook (void) { __free_hook = check_free; __malloc_hook = check_malloc; __realloc_hook = check_realloc; current_free = 0; strict_free_check = 1; } void really_free_one_entry (void *, int, int *); DEFUN ("really-free", Freally_free, 0, 1, "P", /* Actually free the storage held by the free() debug hook. A no-op if the free hook is disabled. */ (arg)) { int count[2]; Lisp_Object lisp_count[2]; if ((__free_hook != 0) && pointer_table) { count[0] = 0; count[1] = 0; __free_hook = 0; maphash ((maphash_function)really_free_one_entry, pointer_table, (void *)&count); memset (free_queue, 0, sizeof (free_queue_entry) * FREE_QUEUE_LIMIT); current_free = 0; __free_hook = check_free; XSETINT (lisp_count[0], count[0]); XSETINT (lisp_count[1], count[1]); return Fcons (lisp_count[0], lisp_count[1]); } else return Fcons (make_int (0), make_int (0)); } void really_free_one_entry (void *key, int contents, int *countp) { if (contents < 0) { free (key); #ifdef UNMAPPED_FREE mprotect (key, -contents, PROT_READ | PROT_WRITE | PROT_EXEC); #endif remhash (key, pointer_table); countp[0]++; countp[1] += -contents; } } void syms_of_free_hook (void) { DEFSUBR (Freally_free); } #else void (*__free_hook)() = check_free; void *(*__malloc_hook)() = check_malloc; void *(*__realloc_hook)() = check_realloc; #endif #endif /* !defined(HAVE_LIBMCHECK) */ #if defined(DEBUG_INPUT_BLOCKING) || defined (DEBUG_GCPRO) /* Note: There is no more input blocking in XEmacs */ typedef enum { block_type, unblock_type, totally_type, gcpro1_type, gcpro2_type, gcpro3_type, gcpro4_type, ungcpro_type } blocktype; struct block_input_history_struct { char *file; int line; blocktype type; int value; #ifdef SAVE_STACK fun_entry backtrace[TRACE_LIMIT]; #endif }; typedef struct block_input_history_struct block_input_history; #endif #ifdef DEBUG_INPUT_BLOCKING int blhistptr; #define BLHISTLIMIT 1000 block_input_history blhist[BLHISTLIMIT]; note_block_input (char *file, int line) { note_block (file, line, block_type); if (interrupt_input_blocked > 2) abort(); } note_unblock_input (char* file, int line) { note_block (file, line, unblock_type); } note_totally_unblocked (char* file, int line) { note_block (file, line, totally_type); } note_block (char *file, int line, blocktype type) { #ifdef SAVE_STACK FRAME start_frame; init_frame (&start_frame); #endif blhist[blhistptr].file = file; blhist[blhistptr].line = line; blhist[blhistptr].type = type; blhist[blhistptr].value = interrupt_input_blocked; #ifdef SAVE_STACK save_backtrace (&start_frame, blhist[blhistptr].backtrace); #endif blhistptr++; if (blhistptr >= BLHISTLIMIT) blhistptr = 0; } #endif #ifdef DEBUG_GCPRO int gcprohistptr; #define GCPROHISTLIMIT 1000 block_input_history gcprohist[GCPROHISTLIMIT]; static void log_gcpro (char *file, int line, struct gcpro *value, blocktype type) { FRAME start_frame; if (type == ungcpro_type) { if (value == gcprolist) goto OK; if (! gcprolist) abort (); if (value == gcprolist->next) goto OK; if (! gcprolist->next) abort (); if (value == gcprolist->next->next) goto OK; if (! gcprolist->next->next) abort (); if (value == gcprolist->next->next->next) goto OK; abort (); OK:; } #ifdef SAVE_STACK init_frame (&start_frame); #endif gcprohist[gcprohistptr].file = file; gcprohist[gcprohistptr].line = line; gcprohist[gcprohistptr].type = type; gcprohist[gcprohistptr].value = (int) value; #ifdef SAVE_STACK save_backtrace (&start_frame, gcprohist[gcprohistptr].backtrace); #endif gcprohistptr++; if (gcprohistptr >= GCPROHISTLIMIT) gcprohistptr = 0; } void debug_gcpro1 (char *file, int line, struct gcpro *gcpro1, Lisp_Object *var) { gcpro1->next = gcprolist; gcpro1->var = var; gcpro1->nvars = 1; gcprolist = gcpro1; log_gcpro (file, line, gcpro1, gcpro1_type); } void debug_gcpro2 (char *file, int line, struct gcpro *gcpro1, struct gcpro *gcpro2, Lisp_Object *var1, Lisp_Object *var2) { gcpro1->next = gcprolist; gcpro1->var = var1; gcpro1->nvars = 1; gcpro2->next = gcpro1; gcpro2->var = var2; gcpro2->nvars = 1; gcprolist = gcpro2; log_gcpro (file, line, gcpro2, gcpro2_type); } void debug_gcpro3 (char *file, int line, struct gcpro *gcpro1, struct gcpro *gcpro2, struct gcpro *gcpro3, Lisp_Object *var1, Lisp_Object *var2, Lisp_Object *var3) { gcpro1->next = gcprolist; gcpro1->var = var1; gcpro1->nvars = 1; gcpro2->next = gcpro1; gcpro2->var = var2; gcpro2->nvars = 1; gcpro3->next = gcpro2; gcpro3->var = var3; gcpro3->nvars = 1; gcprolist = gcpro3; log_gcpro (file, line, gcpro3, gcpro3_type); } void debug_gcpro4 (char *file, int line, struct gcpro *gcpro1, struct gcpro *gcpro2, struct gcpro *gcpro3, struct gcpro *gcpro4, Lisp_Object *var1, Lisp_Object *var2, Lisp_Object *var3, Lisp_Object *var4) { log_gcpro (file, line, gcpro4, gcpro4_type); gcpro1->next = gcprolist; gcpro1->var = var1; gcpro1->nvars = 1; gcpro2->next = gcpro1; gcpro2->var = var2; gcpro2->nvars = 1; gcpro3->next = gcpro2; gcpro3->var = var3; gcpro3->nvars = 1; gcpro4->next = gcpro3; gcpro4->var = var4; gcpro4->nvars = 1; gcprolist = gcpro4; } void debug_gcpro5 (char *file, int line, struct gcpro *gcpro1, struct gcpro *gcpro2, struct gcpro *gcpro3, struct gcpro *gcpro4, struct gcpro *gcpro5, Lisp_Object *var1, Lisp_Object *var2, Lisp_Object *var3, Lisp_Object *var4, Lisp_Object *var5) { log_gcpro (file, line, gcpro5, gcpro5_type); gcpro1->next = gcprolist; gcpro1->var = var1; gcpro1->nvars = 1; gcpro2->next = gcpro1; gcpro2->var = var2; gcpro2->nvars = 1; gcpro3->next = gcpro2; gcpro3->var = var3; gcpro3->nvars = 1; gcpro4->next = gcpro3; gcpro4->var = var4; gcpro4->nvars = 1; gcpro5->next = gcpro4; gcpro5->var = var5; gcpro5->nvars = 1; gcprolist = gcpro5; } void debug_ungcpro (char *file, int line, struct gcpro *gcpro1) { log_gcpro (file, line, gcpro1, ungcpro_type); gcprolist = gcpro1->next; } void show_gcprohist (void) { int i, j; for (i = 0, j = gcprohistptr; i < GCPROHISTLIMIT; i++, j++) { if (j >= GCPROHISTLIMIT) j = 0; printf ("%3d %s %d %s 0x%x\n", j, gcprohist[j].file, gcprohist[j].line, (gcprohist[j].type == gcpro1_type ? "GCPRO1" : gcprohist[j].type == gcpro2_type ? "GCPRO2" : gcprohist[j].type == gcpro3_type ? "GCPRO3" : gcprohist[j].type == gcpro4_type ? "GCPRO4" : gcprohist[j].type == ungcpro_type ? "UNGCPRO" : "???"), gcprohist[j].value); } fflush (stdout); } #endif