*/
+/* This file implements memory leak checker and basic memory corruption
+ and double free checker. It is multi-thread safe. It does the
+ following:
+
+ o Tracks all memory allocations and report any unfreed memory at the
+ end of the program with backtrace where the memory was allocated.
+
+ o Checks if a memory location has been freed already and abort the
+ program with the backtrace of the location of the double free.
+
+ o Checks if a given pointer has been allocated at all and abort the
+ program with the backtrace where the invalid free was given.
+
+ o Checks at the time of free if the memory was written out of bounds
+ (overflow) and abort with the backtrace of the free. The backtrace
+ might not help to find the overflow but at least it is detected.
+ By setting SILC_MALLOC_DUMP the memory is dummped to help and see
+ what it contains.
+
+ The following environment variables can be used:
+
+ SILC_MALLOC_NO_FREE
+
+ When set to value 1, the program doesn't actually free any memory.
+ This provides more detailed information especially in case of double
+ free. If the location of the double free cannot be located, by
+ setting this variable the program will show where the memory was
+ originally allocated and freed.
+
+ SILC_MALLOC_DUMP
+
+ When set to value 1, in case of fatal error, dumps the memory location,
+ if possible. This can help see what the memory contains.
+
+ To work correctly this of course expects that code uses SILC memory
+ allocation and access routines.
+
+*/
+
#include "silcruntime.h"
#ifdef SILC_STACKTRACE
+#include <execinfo.h>
static void *st_blocks = NULL;
static unsigned long st_blocks_count = 0;
+static unsigned long st_num_malloc = 0;
static SilcBool dump = FALSE;
static SilcBool malloc_check = FALSE;
+static SilcBool no_free = FALSE;
+static SilcBool dump_mem = FALSE;
+static SilcMutex lock = NULL;
#ifdef SILC_DEBUG
#define SILC_ST_DEPTH 15
/* Memory block with stack trace */
typedef struct SilcStBlockStruct {
- unsigned int dumpped : 1; /* Block is dumpped */
- unsigned int depth : 8; /* Depth of stack trace */
- unsigned int line : 23; /* Allocation line in program */
- void *stack[SILC_ST_DEPTH]; /* Stack trace */
- const char *file; /* Allocation file in program */
- unsigned long size; /* Allocated memory size */
struct SilcStBlockStruct *next;
struct SilcStBlockStruct *prev;
+ void *stack[SILC_ST_DEPTH]; /* Stack trace */
+ const char *file; /* Allocation file in program */
+ const char *free_file; /* Free file in program */
+ SilcUInt32 size; /* Allocated memory size */
+ SilcUInt16 line; /* Allocation line in program */
+ SilcUInt16 free_line; /* Free line in program */
+ SilcUInt16 depth; /* Depth of stack trace */
+ SilcUInt16 dumpped; /* Block is dumpped */
+ SilcUInt32 bound; /* Top bound */
} *SilcStBlock;
-/* Get current frame pointer */
-#define SILC_ST_GET_FP(ret_fp) \
-do { \
- register void *cfp; \
- asm volatile ("movl %%ebp, %0" : "=r" (cfp)); \
- (ret_fp) = cfp; \
-} while(0);
-
-#define SILC_ST_GET_SIZE(size) ((size + sizeof(struct SilcStBlockStruct)))
+#define SILC_ST_TOP_BOUND 0xfeed1977
+#define SILC_ST_BOTTOM_BOUND 0x9152beef
+#define SILC_ST_GET_SIZE(size) ((size + sizeof(struct SilcStBlockStruct) + 4))
#define SILC_ST_GET_STACK(p) ((SilcStBlock)(((unsigned char *)p) - \
sizeof(struct SilcStBlockStruct)))
#define SILC_ST_GET_PTR(p) (((unsigned char *)p) + \
sizeof(struct SilcStBlockStruct))
+#define SILC_ST_GET_BOUND(p, size) (SilcUInt32 *)(((unsigned char *)p) + \
+ SILC_ST_GET_SIZE(size) - 4)
-void silc_st_stacktrace(SilcStBlock stack)
+void silc_st_abort(SilcStBlock stack, const char *file, int line,
+ char *fmt, ...)
{
- void *fp;
+ void *bt[SILC_ST_DEPTH];
+ SilcUInt32 *bound;
+ va_list va;
+ int btc;
+
+ va_start(va, fmt);
+ vfprintf(stderr, fmt, va);
+ va_end(va);
+
+ fprintf(stderr, "----- BACKTRACE -----\n%s:%d:\n", file, line);
+ btc = backtrace(bt, SILC_ST_DEPTH);
+ backtrace_symbols_fd(bt, btc, 2);
+
+ if (stack) {
+ fprintf(stderr, "----- MEMORY TRACE -----\n");
+ if (stack->free_file)
+ fprintf(stderr, "Freed at: %s:%d\n", stack->free_file,
+ stack->free_line);
+ fprintf(stderr, "Originally allocated at:\n");
+ fprintf(stderr, "%s:%d:\n", stack->file, stack->line);
+ backtrace_symbols_fd(stack->stack, stack->depth, 2);
+ fflush(stderr);
+
+ if (dump_mem) {
+ fprintf(stderr, "----- MEMORY HEADER -----\n");
+ fprintf(stderr, "Header length: %lu, total length %lu\n",
+ sizeof(struct SilcStBlockStruct), SILC_ST_GET_SIZE(stack->size));
+ silc_hexdump((void *)stack, sizeof(struct SilcStBlockStruct), stderr);
+ fflush(stderr);
+ fprintf(stderr, "Header bound is: %p\n",
+ SILC_32_TO_PTR(stack->bound));
+ if (stack->bound != SILC_ST_TOP_BOUND) {
+ fprintf(stderr, "Header bound should be: %p\n",
+ SILC_32_TO_PTR(SILC_ST_TOP_BOUND));
+ fprintf(stderr, "MEMORY IS CORRUPTED (UNDERFLOW)!\n");
+ }
+
+ fprintf(stderr, "----- USER MEMORY -----\n");
+ fprintf(stderr, "Length: %d\n", stack->size);
+ silc_hexdump(((unsigned char *)stack) +
+ sizeof(struct SilcStBlockStruct), stack->size, stderr);
+ fflush(stderr);
+
+ fprintf(stderr, "----- MEMORY FOOTER -----\n");
+ bound = SILC_ST_GET_BOUND(stack, stack->size);
+ silc_hexdump((unsigned char *)bound, 4, stderr);
+ fprintf(stderr, "Footer bound is: %p\n", SILC_32_TO_PTR(*bound));
+ if (*bound != SILC_ST_BOTTOM_BOUND) {
+ fprintf(stderr, "Footer bound should be: %p\n",
+ SILC_32_TO_PTR(SILC_ST_BOTTOM_BOUND));
+ fprintf(stderr, "MEMORY IS CORRUPTED (OVERFLOW)!\n");
+ }
+ }
+ }
+ fflush(stderr);
+
+ abort();
+}
+
+void silc_st_stacktrace(SilcStBlock stack)
+{
if (!dump) {
atexit(silc_st_dump);
dump = TRUE;
}
if (!malloc_check) {
+ const char *var;
+
+ var = silc_getenv("SILC_MALLOC_NO_FREE");
+ if (var && *var == '1')
+ no_free = TRUE;
+
+ var = silc_getenv("SILC_MALLOC_DUMP");
+ if (var && *var == '1')
+ dump_mem = TRUE;
+
/* Linux libc malloc check */
- setenv("MALLOC_CHECK_", "2", 1);
+ silc_setenv("MALLOC_CHECK_", "3");
/* NetBSD malloc check */
- setenv("MALLOC_OPTIONS", "AJ", 1);
+ silc_setenv("MALLOC_OPTIONS", "AJ");
malloc_check = TRUE;
- }
- /* Save the stack */
- SILC_ST_GET_FP(fp);
- for (stack->depth = 0; fp; stack->depth++) {
- if (stack->depth == SILC_ST_DEPTH)
- break;
-
- /* Get program pointer and frame pointer from this frame */
- stack->stack[stack->depth] = *((void **)(((unsigned char *)fp) + 4));
- fp = *((void **)fp);
+ silc_mutex_alloc(&lock);
}
+
+ /* Get backtrace */
+ stack->depth = backtrace(stack->stack, SILC_ST_DEPTH);
}
void *silc_st_malloc(size_t size, const char *file, int line)
{
SilcStBlock stack = (SilcStBlock)malloc(SILC_ST_GET_SIZE(size));
- assert(stack != NULL);
+
+ if (!stack)
+ return NULL;
stack->dumpped = 0;
stack->file = file;
+ stack->free_file = NULL;
stack->line = line;
stack->size = size;
+ stack->bound = SILC_ST_TOP_BOUND;
silc_st_stacktrace(stack);
+ silc_mutex_lock(lock);
+
stack->next = st_blocks;
stack->prev = NULL;
if (st_blocks)
((SilcStBlock)st_blocks)->prev = stack;
st_blocks = stack;
st_blocks_count++;
+ st_num_malloc++;
+
+ silc_mutex_unlock(lock);
+
+ *SILC_ST_GET_BOUND(stack, size) = SILC_ST_BOTTOM_BOUND;
return SILC_ST_GET_PTR(stack);
}
stack = SILC_ST_GET_STACK(ptr);
if (stack->size >= size) {
+ /* Must update footer when the size changes */
+ if (stack->size != size)
+ *SILC_ST_GET_BOUND(stack, size) = SILC_ST_BOTTOM_BOUND;
+
stack->size = size;
return ptr;
} else {
void silc_st_free(void *ptr, const char *file, int line)
{
- SilcStBlock stack;
+ SilcStBlock stack, s;
if (!ptr)
return;
+ /* Check for double free */
+ if (!memcmp((unsigned char *)ptr - sizeof(struct SilcStBlockStruct),
+ "\x47\x47\x47\x47", 4))
+ silc_st_abort(no_free ? ptr - sizeof(struct SilcStBlockStruct) : NULL,
+ file, line, "SILC_MALLOC: double free: %p already freed\n",
+ ptr - sizeof(struct SilcStBlockStruct));
+
stack = SILC_ST_GET_STACK(ptr);
+
+ silc_mutex_lock(lock);
+
+ /* Check if we have ever made this allocation */
+ for (s = st_blocks; s; s = s->next)
+ if (s == stack)
+ break;
+ if (s == NULL)
+ silc_st_abort(NULL, file, line,
+ "SILC_MALLOC: %p was never allocated\n", stack);
+
+ /* Check for underflow */
+ if (stack->bound != SILC_ST_TOP_BOUND)
+ silc_st_abort(stack, file, line,
+ "SILC_MALLOC: %p was written out of bounds (underflow)\n",
+ stack);
+
+ /* Check for overflow */
+ if (*SILC_ST_GET_BOUND(stack, stack->size) != SILC_ST_BOTTOM_BOUND)
+ silc_st_abort(stack, file, line,
+ "SILC_MALLOC: %p was written out of bounds (overflow)\n",
+ stack);
+
if (stack->next)
stack->next->prev = stack->prev;
if (stack->prev)
st_blocks_count--;
- memset(stack, 'F', SILC_ST_GET_SIZE(stack->size));
+ silc_mutex_unlock(lock);
+
+ stack->free_file = file;
+ stack->free_line = line;
+
+ if (no_free) {
+ memset(stack, 0x47, 8);
+ return;
+ }
+
+ memset(stack, 0x47, SILC_ST_GET_SIZE(stack->size));
+
free(stack);
}
return silc_st_memdup(string, strlen(string), file, line);
}
-/* Dumps the stack into file if there are leaks. The file can be read
- with a special stacktrace tool. */
+/* Dumps the stack into file if there are leaks. */
void silc_st_dump(void)
{
SilcStBlock stack, s;
unsigned long leaks = 0, blocks, bytes;
FILE *fp = NULL;
+ char **syms, *cp;
int i;
+ SilcMutex l;
+
+ l = lock;
+ lock = NULL;
+ silc_mutex_free(l);
for (stack = st_blocks; stack; stack = stack->next) {
bytes = blocks = 0;
fp = stderr;
}
+ /* Get symbol names */
+ syms = backtrace_symbols(stack->stack, stack->depth);
+
+ /* Find number of leaks and bytes leaked for this leak */
for (s = stack; s; s = s->next) {
if (s->file == stack->file && s->line == stack->line &&
s->depth == stack->depth &&
}
if (blocks) {
- fprintf(fp, "<stacktrace>%s:%d: #blocks=%lu, bytes=%lu\n",
+ fprintf(fp, "<leak>%s:%d: #blocks=%lu, bytes=%lu\n",
stack->file, stack->line, blocks, bytes);
- for (i = 0; i < stack->depth; i++)
- fprintf(fp, "\tpc=%p\n", stack->stack[i]);
+ for (i = 0; i < stack->depth; i++) {
+ if (syms) {
+ cp = syms[i];
+ if (strchr(cp, '('))
+ cp = strchr(cp, '(') + 1;
+ else if (strchr(cp, ' '))
+ cp = strchr(cp, ' ') + 1;
+ if (strchr(cp, ')'))
+ *strchr(cp, ')') = ' ';
+ fprintf(fp, "\t%s\n", cp);
+ } else {
+ fprintf(fp, "\tpc=%p\n", stack->stack[i]);
+ }
+ }
+ fprintf(fp, "\n");
+ free(syms);
}
}
"-----------------------------------------\n"
"-----------------------------------------\n",
leaks, st_blocks_count);
+ fprintf(stderr, "Number of allocations: %lu\n", st_num_malloc);
}
if (fp && fp != stderr)
projects / runtime.git / commitdiff