OpenSSL Library - 讀取 X509 certificate 的資訊

typedef enum {
    OK,
    ERROR_UNKNOWN,
    ERROR_ALLOCATE_MEMORY_IS_FAILED,
    ERROR_X509_IS_INVALID,
    ERROR_X509_IS_EXPIRED,
    ERROR_CA_FILE_IS_NOT_FOUND
} State;

typedef enum {
    DER,
    PEM
} Inform;

#define TRUE 1
#define FALSE 0
typedef unsigned char boolean;

boolean show_X509_info(
    const char *cert_filepath, 
    Inform inform,
    X509 **out_x509,
    State *state);

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/x509.h>
#include "show-x509-info.h"

boolean show_X509_info(
    const char *cert_filepath, 
    Inform inform,
    X509 **out_x509,
    State *state)
{
    boolean rc = FALSE;
    FILE *fp = NULL;
    X509 *x509data = NULL;
    
    X509_free(*out_x509);

    fp = fopen(cert_filepath, "r");
    if (fp == NULL) {
        *state = ERROR_CA_FILE_IS_NOT_FOUND;
        return FALSE;
    }

    if (inform == DER) {
        d2i_X509_fp(fp, &x509data);
    }
    else {
        PEM_read_X509(fp, &x509data, NULL, NULL);
    }
    fclose(fp);
    if (x509data == NULL) {
	    *state = ERROR_X509_IS_INVALID;
	    return FALSE;
    }

    char issuer_name[1024];
    char subject_name[1024];
    char now_timez[16]; // YYYYMMDDhhmmss: 15, yyMMDDhhmmss: 13
    time_t t;
    struct tm tm;

    X509_NAME_oneline(X509_get_issuer_name(x509data), issuer_name, 
                    sizeof(issuer_name));
    X509_NAME_oneline(X509_get_subject_name(x509data), subject_name, 
                    sizeof(subject_name));

    printf("Issuer  name: %s\n", issuer_name);
    printf("Subject name: %s\n", subject_name);
    printf("Validity from: %s\n", x509data->cert_info->validity->notBefore->data);
    printf("Validity till: %s\n", x509data->cert_info->validity->notAfter->data);
    // x509data->cert_info->validity->notBefore->length
    
    if (strcmp(issuer_name, subject_name) != 0) {
        *state = ERROR_X509_IS_INVALID;
        goto end_func;
    }
    
    t = time(NULL);
    if (localtime_r(&t, &tm) == NULL) {
	    *state = ERROR_ALLOCATE_MEMORY_IS_FAILED;
        goto end_func;
    }

    strftime(now_timez, sizeof(now_timez), "%y%m%d%H%M%SZ", &tm);
    // notBefore < now_timez < notAfter
    //     0     <   n       < 0
    if ((0 < strcmp(now_timez, x509data->cert_info->validity->notBefore->data))
      && (strcmp(now_timez, x509data->cert_info->validity->notAfter->data) <0) )
    {
        rc = TRUE;
    }
    else
    {
	    *state = ERROR_X509_IS_EXPIRED;
        rc = FALSE;
    }

  end_func:
    *out_x509 = x509data;
    return rc;
}

// gcc -lssl  -o x509-cert-info x509-cert-info.c show-x509-info.c
#include <stdio.h>
#include <stdlib.h>
#include <openssl/x509.h>
#include "show-x509-info.h"

int main(int argc, char *args[])
{
    char *cert_filepath = NULL;
    State state = ERROR_UNKNOWN;
    X509 *x509 = NULL;
    int inform = DER;

    if (argc < 2) {
        printf("Show X509 certificate's information.\n");
        printf("Usage: %s <cert_filepath> [format]\n", args[0]);
        printf("Format: DER or PEM, Default format is DER.\n");
        printf("Return status:\n");
        printf("\t0: ok.\n");
        printf("\t1: UNKNOWN.\n");
        printf("\t2: ALLOCATE_MEMORY_IS_FAILED.\n");
        printf("\t3: X509_IS_INVALID.\n");
        printf("\t4: X509_IS_EXPIRED.\n");
        printf("\t5: CA_FILE_IS_NOT_FOUND.\n");
        return 255;
    }
    
    cert_filepath = args[1];
    
    if (argc >= 3) {
        if (args[2][0] == 'P' || args[2][0] == 'p')
            inform = PEM;
    }

    printf("Information of %s:\n", cert_filepath);
    if (!show_X509_info(cert_filepath, inform, &x509, &state)) {
        switch (state)
        {
        case ERROR_ALLOCATE_MEMORY_IS_FAILED:
            puts("ERROR: ALLOCATE_MEMORY_IS_FAILED\n");
            break;
        case ERROR_X509_IS_INVALID:
            puts("ERROR: X509_IS_INVALID\n");
            break;
        case ERROR_X509_IS_EXPIRED:
            puts("ERROR: X509_IS_EXPIRED\n");
            break;
        case ERROR_CA_FILE_IS_NOT_FOUND:
            puts("ERROR: CA_FILE_IS_NOT_FOUND\n");
            break;
        default:
            puts("ERROR: UNKNOWN\n");
            break;
        }
        return state;
    }

    return 0;
}