wxtest.c

#include <stdio.h>
#include <string.h>

#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>

// Alternatively, /dev/shm/test, /var/tmp/test, /home/username/test, /home/.local/share/appname/test, etc.
static const char *const path = "/tmp/test";
static const char code[] = "\xeb\x1e\x5e\x48\x31\xc0\xb0\x01\x48\x89\xc7\x48\x89\xfa\x48\x83\xc2\x0e\x0f\x05\x48\x31\xc0\x48\x83\xc0\x3c\x48\x31\xff\x0f\x05\xe8\xdd\xff\xff\xff\x48\x65\x6c\x6c\x6f\x2c\x20\x77\x6f\x72\x6c\x64\x21\x0a";

int main(void) {
    size_t len = 4096;
    int fd = open("/tmp/test", O_RDWR|O_CREAT, 0700);
    if (fd == -1) {
        perror("shm_open");
        return 1;
    }
    if (ftruncate(fd, len) == -1) {
        perror("ftruncate");
        return 1;
    }
    void *rw = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
    if (rw == MAP_FAILED) {
        perror("mmap");
        return 1;
    }

    void *rx = mmap(NULL, len, PROT_READ|PROT_EXEC, MAP_SHARED, fd, 0);
    if (rx == MAP_FAILED) {
        perror("mmap");
        return 1;
    }

    memcpy(rw, code, sizeof(code));
    (*(void(*)()) rx)();

    close(fd);
    if (unlink("/tmp/test") == -1) {
        perror("unlink");
        return 1;
    }
}