/* SPDX-License-Identifier: BSD-3-Clause */

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

#include "tools/fapi/tss2_template.h"

/* Context struct used to store passed commandline parameters */
static struct cxt {
    size_t  numBytes;
    char   *filename;
    bool    overwrite;
    bool    hex;
} ctx;

/* Parse commandline parameters */
static bool on_option(char key, char *value) {
    switch (key) {
    case 'n': {
        /*N.B. In theory size_t can be unsigned long, which is more than
         * uint32, in practice this will never happen */
        uint32_t i;
        if (!tpm2_util_string_to_uint32 (value, &i) || i == 0) {
            fprintf (stderr, "%s cannot be converted to a positive integer or "\
                "is larger than 2**32 - 1\n", value);
            return false;
        }
        ctx.numBytes = i; /* cast from uint32 to size_t */
        }
        break;
    case 'f':
        ctx.overwrite = true;
        break;
    case 'o':
        ctx.filename = value;
        break;
    case 0:
        ctx.hex = true;
        break;
    }
    return true;
}

/* Define possible commandline parameters */
static bool tss2_tool_onstart(tpm2_options **opts) {
    struct option topts[] = {
        {"numBytes", required_argument, NULL, 'n'},
        {"force"    , no_argument      , NULL, 'f'},
        /* output file */
        {"data"   , required_argument, NULL, 'o'},
        {"hex",          no_argument,       NULL,  0}
    };
    return (*opts = tpm2_options_new ("fn:o:", ARRAY_LEN(topts), topts,
                                      on_option, NULL, 0)) != NULL;
}

/* Execute specific tool */
static int tss2_tool_onrun (FAPI_CONTEXT *fctx) {
    /* Check availability of required parameters */
    if (!ctx.filename) {
        fprintf (stderr, "No filename for data was provided, use --data\n");
        return -1;
    }
    if (!ctx.numBytes) {
        fprintf (stderr, "No amount of bytes was provided, use --numBytes\n");
        return -1;
    }

    /* Execute FAPI command with passed arguments */
    uint8_t *data;
    TSS2_RC r = Fapi_GetRandom (fctx, ctx.numBytes, &data);
    if (r != TSS2_RC_SUCCESS) {
        LOG_PERR ("Fapi_GetRandom", r);
        return 1;
    }

    if (ctx.hex) {
        char* str = malloc (ctx.numBytes*2 + 1);
        if (!str) {
            Fapi_Free (data);
            LOG_ERR ("malloc(2) failed: %m\n");
            return 1;
        }
        for (size_t i = 0; i<ctx.numBytes; i++) {
            sprintf(str+i*2,"%02x",data[i]);
        }
        /* Write returned data to file(s) */
        r = open_write_and_close (ctx.filename, ctx.overwrite, str, strlen(str));
        free(str);
    }
    else {
        /* Write returned data to file(s) */
        r = open_write_and_close (ctx.filename, ctx.overwrite, data,
            ctx.numBytes);
    }
    if (r) {
        Fapi_Free (data);
        return 1;
    }

    Fapi_Free (data);
    return 0;
}

TSS2_TOOL_REGISTER("getrandom", tss2_tool_onstart, tss2_tool_onrun, NULL)