#include <stdio.h>
#include <stdlib.h>
#include <sys/capability.h>

#define die(msg) \
    do { perror(msg); return EXIT_FAILURE; } while (0)

const char* usage =
"Usage: %s <textual-cap-set>\n"
"See man page for cap_to_text(3) for more information.\n";

int main(int argc, char *argv[]) {
    cap_t caps;
    char *capstring;

    if (argc != 2) {
        fprintf(stderr, usage, argv[0]);
        return EXIT_FAILURE;
    }

    if ((argv[1][0] == '-') && argv[1][1] == 'r') {
        // -r: a common setcap(1) parameter
        // to purge capability info from a file
        return EXIT_SUCCESS;
    }

    caps = cap_from_text(argv[1]);
    if (caps == NULL)
        die("cap_from_text");

    capstring = cap_to_text(caps, NULL);
    if (capstring == NULL)
        die("cap_to_text");

    printf("%s\n", capstring);

    if (cap_free(capstring) != 0 || cap_free(caps) != 0)
        die("cap_free");

    return EXIT_SUCCESS;
}