I have written a c milter for my mail server.
I need to profile my milter daemon on linux. I have used memprof
before , but cant seem to get memprof installed on my Centos 4.4 box.
Which tool do you folks use for profiling.
I just want to see is my daemon process has any memory leaks and where
are they.
The comp.lang.c answer is to use wrappers for the memory allocation
functions that log allocations and deallocations.
Then you can go through the allocation log, and any allocations that don't
get deallocated are probably leaks (though for a long-running process
some of them will be one-time allocations that shouldn't get deallocated).
So you could use something like this:
--------
/*mymalloc.h*/
/*WARNING!! Not compiled or tested, for explanatory purposes only*/
#ifndef H_MYMALLOC
#define H_MYMALLOC
#ifdef MYMALLOC_DEBUG
#include <stddef.h>
void *mymalloc(size_t sz,int line,const char *file);
void *myrealloc(void *p,size_t sz,int line,const char *file);
void myfree(void *p,int line,const char *file);
#define MALLOC(sz) mymalloc(sz,__LINE__,__FILE__)
#define REALLOC(p,sz) myrealloc(p,sz,__LINE__,__FILE__)
#define FREE(p) myfree(p,__LINE__,__FILE__)
#else
#include <stdlib.h>
#define MALLOC malloc
#define REALLOC realloc
#define FREE free
#endif
--------
/*mymalloc.c*/
/*WARNING!! Not compiled or tested, for explanatory purposes only*/
#include <stdio.h>
#include <stdlib.h>
#include "mymalloc.h"
#define LOGFILE "malloc-log"
void *mymalloc(size_t sz,int line,const char *file)
{
void *ptr=malloc(sz);
FILE *out=fopen(LOGFILE,"a");
if(out)
{
fprintf(out,"malloc(%s:%d): requested %lu bytes, malloc returned %p\n",
file,line,(unsigned long)sz,ptr);
fclose(out);
}
return ptr;
}
void *myrealloc(void *oldptr,size_t sz,int line,const char *file)
{
void *newptr;
FILE *out=fopen(LOGFILE,"a");
if(out)
{
fprintf(out,"realloc(%s:%d): old pointer %p, requested %lu bytes, ",
file,line,oldptr,(unsigned long)sz);
}
newptr=realloc(oldptr,sz);
if(out)
{
fprintf(out,"realloc returned %p\n");
fclose(out);
}
return newptr;
}
void *myfree(void *ptr,int line,const char *file)
{
FILE *out=fopen(LOGFILE,"a");
if(out)
{
fprintf(out,"free(%s:%d): freeing %p\n",file,line,ptr);
fclose(out);
}
free(ptr);
}
--------
Replace all of your calls to malloc, realloc, and free with the MALLOC,
REALLOC, and FREE macros, and for your leak-testing build define
MYMALLOC_DEBUG and include mymalloc.c in the build.
Most automated memory profilers will (I expect) do something like this
with a built-in analysis instead of writing a log file and then doing
the analysis offline (which using these wrappers you'll have to either
do by hand or build a tool to do).
dave
Both milters and memory usage profiling are off-topic here,