Obtaining and printing a memory map

Use the following sample code segment to obtain and then print the contents of a memory map:

#include <stdio.h>
#include <backtrace.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

int main(int argc, char *argv[])
{
    char out[1024];

    bt_accessor_t acc;
    bt_memmap_t memmap;

    if (bt_init_accessor(&acc, BT_SELF) == -1)
    {
        fprintf( stderr, "%s:%i %s (%i)%s\n", __FUNCTION__, __LINE__,
                 "bt_init_accessor", errno, strerror(errno));
        return EXIT_FAILURE;
    }

    if (bt_load_memmap( &acc, &memmap) == -1)
    {
        fprintf( stderr, "%s:%i %s (%i)%s\n", __FUNCTION__, __LINE__,
                 "bt_load_memmap", errno, strerror(errno));
        return EXIT_FAILURE;
    }

    if (bt_sprn_memmap(&memmap, out, sizeof(out)) == -1)
    {
        fprintf( stderr, "%s:%i %s (%i)%s\n", __FUNCTION__, __LINE__,
                 "bt_sprn_memmap", errno, strerror(errno));
        return EXIT_FAILURE;
    }

    /* Make sure that the string is null-terminated. */
    out[sizeof(out) - 1] = '\0';
    puts(out);

    bt_unload_memmap( &memmap );

    if (bt_release_accessor(&acc) == -1)
    {
        fprintf( stderr, "%s:%i %s (%i)%s\n", __FUNCTION__, __LINE__,
                 "bt_release_accessor", errno, strerror(errno));
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}

Additional notes about memory:

• The formula for calculating memory used by a memory map is roughly the following:

  (16 + strlen(filename)) * num_files
    

• Some memory is temporarily allocated while the memory map is read. For example, an executable with three shared libraries loaded (assuming an average file name length of 40 characters, and excluding overhead from malloc()), would consume 224 bytes.