uuid.c

#include <stdio.h>
#include <stdint.h>
#include <openssl/rand.h>
#include <errno.h>
#include <lua.h>
#include <lauxlib.h>
#include <lualib.h> 


/** @brief Generate a Version 4 UUID according to RFC-4122
 *
 * Uses the openssl RAND_bytes function to generate a
 * Version 4 UUID.
 *
 * @param buffer A buffer that is at least 38 bytes long.
 * @retval 1 on success, 0 otherwise.
 */
int uuid_v4_gen(char *buffer) {
    union {
        struct {
            uint32_t time_low;
            uint16_t time_mid;
            uint16_t time_hi_and_version;
            uint8_t  clk_seq_hi_res;
            uint8_t  clk_seq_low;
            uint8_t  node[6];
        };
	uint8_t __rnd[16];
    } uuid;

    int rc = RAND_bytes(uuid.__rnd, sizeof(uuid));

    // Refer Section 4.2 of RFC-4122
    // https://tools.ietf.org/html/rfc4122#section-4.2
    uuid.clk_seq_hi_res = (uint8_t) ((uuid.clk_seq_hi_res & 0x3F) | 0x80);
    uuid.time_hi_and_version = (uint16_t) ((uuid.time_hi_and_version & 0x0FFF) | 0x4000);
    snprintf(buffer, 38, "%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
    uuid.time_low, uuid.time_mid, uuid.time_hi_and_version,
    uuid.clk_seq_hi_res, uuid.clk_seq_low,
    uuid.node[0], uuid.node[1], uuid.node[2],
    uuid.node[3], uuid.node[4], uuid.node[5]);

    return rc;
}

static int getuuid (lua_State *L) {

    // Get the number of stack arguments
    //arguments = lua_gettop(L);	

    char uuidv4[38];

    int rc = uuid_v4_gen(uuidv4);

    //if(rc == 1)
     //	printf("%s\n", uuidv4);
    //else
    //printf("Not enough random bytes for PRNG");
    //return 0;

    if(rc == 0) {

    }
    // Push the result onto the stack
    lua_pushstring(L, uuidv4);
    //free(uuidv4);
    // Return the number of return values
    return(1);

}

LUALIB_API int luaopen_uuid(lua_State *L) {
    lua_register(L, "uuid", getuuid);
    return 0;
}