example C program to read and parse certificate

malloc.c

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <stdint.h>
#include <sys/mman.h>
#include <openssl/ssl.h>
#include <malloc.h>
#include <unistd.h>

#define ngx_align_ptr(p, a) \
        (u_char *) (((uintptr_t) (p) + ((uintptr_t) a - 1)) & ~((uintptr_t) a - 1))

ngx_http_lua_limit_data_segment(void) {
        if (sbrk(0) < (void *) 0x40000000LL) {
                mmap(ngx_align_ptr(sbrk(0), getpagesize()), 1, PROT_READ,
                                MAP_FIXED|MAP_PRIVATE|MAP_ANON, -1, 0);
        }
}

void read_cert() {
        const char ca_bundlestr[] = "/etc/ssl/certs/ca-certificates.crt";

        BIO               *outbio = NULL;
        int ret;

        SSL_CTX *ctx;

        outbio  = BIO_new_fp(stdout, BIO_NOCLOSE);

        SSL_library_init();
        SSL_load_error_strings();
        OpenSSL_add_all_algorithms();

        ctx = SSL_CTX_new(SSLv23_method());

        SSL_CTX_set_mode(ctx, SSL_MODE_RELEASE_BUFFERS);
        SSL_CTX_set_mode(ctx, SSL_MODE_NO_AUTO_CHAIN);
        SSL_CTX_set_read_ahead(ctx, 1);

        ret = SSL_CTX_load_verify_locations(ctx, ca_bundlestr, NULL);
        if (ret == 0)
                BIO_printf(outbio, "SSL_CTX_load_verify_locations failed");

        BIO_free_all(outbio);
        SSL_CTX_free(ctx);
}


int main() {
        ngx_http_lua_limit_data_segment();
        int i = 0;
        for (i = 0; i < 5000; i++) {
                read_cert();
                //malloc_trim(0);
        }
        malloc_stats();
        usleep(1000 * 60);
}