When a process is killed by a signal that generates a core dump, the kernel writes the dump to a file named core (or core.PID depending on /proc/sys/kernel/core_pattern). RLIMIT_CORE limits the maximum size of this file.

• If RLIMIT_CORE is 0: no core dump file is created at all.
• If the dump would exceed the soft limit, the dump file is truncated at that size and the kernel stops writing.
• If RLIMIT_FSIZE (the file size limit) is smaller than RLIMIT_CORE, the core dump is limited to RLIMIT_FSIZE bytes instead.

Why disable core dumps (set to 0)?

• Core files can be enormous (gigabytes for large processes) and fill up disk space.
• End users generally do not know what to do with core files.
• Security: a core dump contains the process’s entire memory, which could include passwords, encryption keys, or sensitive user data. Disabling core dumps prevents this data from being written to disk.

#include 
#include <sys/resource.h>
#include 
#include 

int main(void)
{
    struct rlimit rl;

    /* Disable core dumps for security */
    rl.rlim_cur = 0;
    rl.rlim_max = 0;
    if (setrlimit(RLIMIT_CORE, &rl) == -1) {
        perror("setrlimit"); exit(1);
    }
    printf("Core dumps disabled\n");

    /* Re-enable core dumps up to 10 MB */
    rl.rlim_cur = 10 * 1024 * 1024;   /* 10 MB soft */
    rl.rlim_max = RLIM_INFINITY;       /* hard: unlimited (root only) */
    /* Note: raising hard limit requires root. For demo, set both to 10 MB */
    rl.rlim_max = 10 * 1024 * 1024;
    if (setrlimit(RLIMIT_CORE, &rl) == -1) {
        perror("setrlimit"); exit(1);
    }
    printf("Core dumps enabled, max 10 MB\n");

    /* Check current value */
    getrlimit(RLIMIT_CORE, &rl);
    printf("Core limit: soft=%lld hard=%lld\n",
           (long long)rl.rlim_cur, (long long)rl.rlim_max);

    /* Cause a crash to generate a core dump */
    /* raise(SIGSEGV); -- uncomment to test */

    return 0;
}
/* Shell equivalent: ulimit -c 0       (disable)
                     ulimit -c 10240   (10 MB, in KB) */