hnvram/hnvram_main.c - vendor/google/platform - Git at Google

 // Copyright 2011 Google Inc. All Rights Reserved.
 // Author: dgentry@google.com (Denny Gentry)

 #define _GNU_SOURCE
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 #include "hmx_upgrade_nvram.h"

 // Max length of data in an NVRAM field
 #define NVRAM_MAX_DATA  4096

 // Number of bytes of GPN to be represented as hex data
 #define GPN_HEX_BYTES 4

 /* To avoid modifying the HMX code, we supply dummy versions of two
  * missing routines to satisfy the linker. These are used when writing
  * the complete NVRAM partiton, which we do not need in this utility. */
 DRV_Error DRV_NANDFLASH_GetNvramHandle(int handle) {
   return DRV_ERR;
 }
 DRV_Error DRV_FLASH_Write(int offset, char *data, int nDataSize) {
   return DRV_ERR;
 }

 void usage(const char* progname) {
   printf("Usage: %s [-d | [-q|-b] -r VARNAME] [-w VARNAME=value]\n", progname);
   printf("\t-d : dump all NVRAM variables\n");
   printf("\t-r VARNAME : read VARNAME from NVRAM\n");
   printf("\t-q : quiet mode, suppress the variable name and equal sign\n");
   printf("\t-b : read VARNAME from NVRAM in raw binary format, e.g. dumping a binary key\n");
   printf("\t-w VARNAME=value : write value to VARNAME in NVRAM.\n");
 }

 // Format of data in the NVRAM
 typedef enum {
   HNVRAM_STRING,    // NUL-terminated string
   HNVRAM_MAC,       // 00:11:22:33:44:55
   HNVRAM_HMXSWVERS, // 2.15
   HNVRAM_UINT8,     // a single byte, generally 0/1 for a boolean.
   HNVRAM_GPN,       // Two formats:
                     // - 4 bytes (old format): printed as 8 digit hex.
                     // - > 4 bytes (new format): printed as NULL-terminated
                     //  string.
   HNVRAM_HEXSTRING  // hexbinary
 } hnvram_format_e;

 typedef struct hnvram_field_s {
   const char* name;
   NVRAM_FIELD_T nvram_type;  // defined in hmx_upgrade_nvram.h
   hnvram_format_e format;
 } hnvram_field_t;

 const hnvram_field_t nvram_fields[] = {
   {"SYSTEM_ID",            NVRAM_FIELD_SYSTEM_ID,            HNVRAM_STRING},
   {"MAC_ADDR",             NVRAM_FIELD_MAC_ADDR,             HNVRAM_MAC},
   {"SERIAL_NO",            NVRAM_FIELD_SERIAL_NO,            HNVRAM_STRING},
   {"LOADER_VERSION",       NVRAM_FIELD_LOADER_VERSION,       HNVRAM_HMXSWVERS},
   {"ACTIVATED_KERNEL_NUM", NVRAM_FIELD_ACTIVATED_KERNEL_NUM, HNVRAM_UINT8},
   {"MTD_TYPE_FOR_KERNEL",  NVRAM_FIELD_MTD_TYPE_FOR_KERNEL,  HNVRAM_STRING},
   {"ACTIVATED_KERNEL_NAME", NVRAM_FIELD_ACTIVATED_KERNEL_NAME, HNVRAM_STRING},
   {"EXTRA_KERNEL_OPT",     NVRAM_FIELD_EXTRA_KERNEL_OPT,     HNVRAM_STRING},
   {"PLATFORM_NAME",        NVRAM_FIELD_PLATFORM_NAME,     HNVRAM_STRING},
   {"1ST_SERIAL_NUMBER",    NVRAM_FIELD_1ST_SERIAL_NUMBER, HNVRAM_STRING},
   {"2ND_SERIAL_NUMBER",    NVRAM_FIELD_2ND_SERIAL_NUMBER, HNVRAM_STRING},
   {"GPN",                  NVRAM_FIELD_GPN,               HNVRAM_GPN},
   {"MAC_ADDR_MOCA",        NVRAM_FIELD_MAC_ADDR_MOCA,     HNVRAM_MAC},
   {"MAC_ADDR_BT",          NVRAM_FIELD_MAC_ADDR_BT,       HNVRAM_MAC},
   {"MAC_ADDR_WIFI",        NVRAM_FIELD_MAC_ADDR_WIFI,     HNVRAM_MAC},
   {"MAC_ADDR_WIFI2",       NVRAM_FIELD_MAC_ADDR_WIFI2,    HNVRAM_MAC},
   {"MAC_ADDR_WAN",         NVRAM_FIELD_MAC_ADDR_WAN,      HNVRAM_MAC},
   {"HDCP_KEY",             NVRAM_FIELD_HDCP_KEY,          HNVRAM_HEXSTRING},
   {"DTCP_KEY",             NVRAM_FIELD_DTCP_KEY,          HNVRAM_HEXSTRING},
   {"GOOGLE_SSL_PEM",       NVRAM_FIELD_GOOGLE_SSL_PEM,    HNVRAM_STRING},
   {"GOOGLE_SSL_CRT",       NVRAM_FIELD_GOOGLE_SSL_CRT,    HNVRAM_STRING},
   {"PAIRED_DISK",          NVRAM_FIELD_PAIRED_DISK,       HNVRAM_STRING},
   {"PARTITION_VER",        NVRAM_FIELD_PARTITION_VER,     HNVRAM_STRING},
   {"HW_VER",               NVRAM_FIELD_HW_VER,            HNVRAM_UINT8},
   {"UITYPE",               NVRAM_FIELD_UITYPE,            HNVRAM_STRING},
   {"LASER_CHANNEL",        NVRAM_FIELD_LASER_CHANNEL,     HNVRAM_STRING},
   {"MAC_ADDR_PON",         NVRAM_FIELD_MAC_ADDR_PON,      HNVRAM_MAC},
   {"PRODUCTION_UNIT",      NVRAM_FIELD_PRODUCTION_UNIT,   HNVRAM_STRING},
   {"BOOT_TARGET",          NVRAM_FIELD_BOOT_TARGET,       HNVRAM_STRING},
 };

 const hnvram_field_t* get_nvram_field(const char* name) {
   int nentries = sizeof(nvram_fields) / sizeof(nvram_fields[0]);
   int i;

   for (i = 0; i < nentries; ++i) {
     const hnvram_field_t* map = &nvram_fields[i];
     if (strcasecmp(name, map->name) == 0) {
       return map;
     }
   }

   return NULL;
 }


 // ------------------ READ NVRAM -----------------------------


 void format_string(const char* data, char* output, int outlen) {
   snprintf(output, outlen, "%s", data);
 }

 void format_mac(const char* data, char* output, int outlen) {
   const unsigned char* mac = (const unsigned char*) data;
   snprintf(output, outlen, "%02hx:%02hx:%02hx:%02hx:%02hx:%02hx",
            mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
 }

 void format_hmxswvers(const char* data, char* output, int outlen) {
   const unsigned char* udata = (const unsigned char*) data;
   snprintf(output, outlen, "%hhu.%hhu", udata[1], udata[0]);
 }

 void format_uint8(const char* data, char* output, int outlen) {
   const unsigned char* d = (const unsigned char*)data;
   snprintf(output, outlen, "%u", d[0]);
 }

 void format_hexstring(const char* data, int datalen, char* output, int outlen) {
   const unsigned char* d = (const unsigned char*)data;
   int i;
   if (outlen < (datalen * 2 + 1)) {
     fprintf(stderr, "%s buffer too small %d < %d",
             __FUNCTION__, outlen, (datalen * 2 + 1));
     exit(1);
   }
   for (i = 0; i < datalen; ++i) {
     snprintf(output + (i * 2), 3, "%02x", d[i]);
   }
 }

 void format_gpn(const char* data, const int data_len, char* output,
                 int outlen) {
   // Format first 4 bytes as 8 digit hex.
   if (data_len == GPN_HEX_BYTES)
     format_hexstring(data, GPN_HEX_BYTES, output, outlen);
   else
     format_string(data, output, outlen);
 }

 char* format_nvram(hnvram_format_e format, const char* data,
                    const int data_len, char* output, int outlen) {
   output[0] = '\0';
   switch(format) {
     case HNVRAM_STRING:    format_string(data, output, outlen); break;
     case HNVRAM_MAC:       format_mac(data, output, outlen); break;
     case HNVRAM_HMXSWVERS: format_hmxswvers(data, output, outlen); break;
     case HNVRAM_UINT8:     format_uint8(data, output, outlen); break;
     case HNVRAM_GPN:       format_gpn(data, data_len, output, outlen); break;
     case HNVRAM_HEXSTRING: format_hexstring(data, data_len, output, outlen);
                            break;
   }
   return output;
 }

 int read_raw_nvram(const char* name, char* output, int outlen) {
   const hnvram_field_t* field = get_nvram_field(name);
   int ret;
   if (field == NULL) {
     return -1;
   }

   if (HMX_NVRAM_GetLength(field->nvram_type, &ret) != DRV_OK) {
     return -1;
   }

   if (ret > outlen) {
     return -1;
   }

   if (HMX_NVRAM_GetField(field->nvram_type, 0, output, outlen) != DRV_OK) {
     return -1;
   }

   return ret;
 }

 char* read_nvram(const char* name, char* output, int outlen, int quiet) {
   const hnvram_field_t* field = get_nvram_field(name);
   if (field == NULL) {
     return NULL;
   }

   char data[NVRAM_MAX_DATA] = {0};
   int data_len = 0;
   if (HMX_NVRAM_GetField(field->nvram_type, 0, data, sizeof(data)) != DRV_OK ||
       HMX_NVRAM_GetLength(field->nvram_type, &data_len) != DRV_OK) {
     return NULL;
   }
   char formatbuf[NVRAM_MAX_DATA * 2];
   char* nv = format_nvram(field->format, data, data_len, formatbuf, sizeof(formatbuf));
   if (quiet) {
     snprintf(output, outlen, "%s", nv);
   } else {
     snprintf(output, outlen, "%s=%s", name, nv);
   }
   return output;
 }


 // ----------------- WRITE NVRAM -----------------------------


 unsigned char* parse_string(const char* input,
                             unsigned char* output, int* outlen) {
   int len = strlen(input);
   if (len > *outlen) {
     len = *outlen;
   }

   strncpy((char*)output, input, len);
   *outlen = len;
   return output;
 }

 unsigned char* parse_mac(const char* input,
                          unsigned char* output, int* outlen) {
   if (*outlen < 6) return NULL;

   if (sscanf(input, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx",
              &output[0], &output[1], &output[2],
              &output[3], &output[4], &output[5]) != 6) {
     return NULL;
   }
   *outlen = 6;
   return output;
 }

 unsigned char* parse_hmxswvers(const char* input,
                                unsigned char* output, int* outlen) {
   if (*outlen < 2) return NULL;

   if (sscanf(input, "%hhd.%hhd", &output[1], &output[0]) != 2) {
     return NULL;
   }
   *outlen = 2;
   return output;
 }

 unsigned char* parse_uint8(const char* input,
                            unsigned char* output, int* outlen) {
   if (*outlen < 1) return NULL;

   output[0] = input[0] - '0';
   *outlen = 1;
   return output;
 }

 int parse_hexdigit(unsigned char c) {
   switch(c) {
     case '0' ... '9': return c - '0';
     case 'a' ... 'f': return 10 + (c - 'a');
     case 'A' ... 'F': return 10 + (c - 'A');
     default: return 0xff;
   }
 }

 unsigned char* parse_hexstring(const char* input,
                                unsigned char* output, int* outlen) {
   int i, len = strlen(input) / 2;
   if (*outlen < len) {
     len = *outlen;
   }

   for (i = 0; i < len; ++i) {
     unsigned char c;
     output[i] = parse_hexdigit(input[2*i]) << 4 |
                 parse_hexdigit(input[2*i+1]);
   }

   *outlen = len;
   return output;
 }

 int is_hexstring(const char* input, int hex_len) {
   int i = 0;
   for (i = 0; i < hex_len; i++) {
     if (!isxdigit(input[i])) {
       return 0;
     }
   }
   if (input[hex_len] != '\0') {
     return 0;
   }
   return 1;
 }

 unsigned char* parse_gpn(const char* input,
                          unsigned char* output, int* outlen) {
   if (*outlen < 4) return NULL;

   // Old GPN format: 8-digit hex string
   if (is_hexstring(input, GPN_HEX_BYTES * 2)) {
     if (sscanf(input, "%02hhx%02hhx%02hhx%02hhx",
                &output[0], &output[1], &output[2], &output[3]) != GPN_HEX_BYTES) {
       return NULL;
     }
     *outlen = GPN_HEX_BYTES;
     return output;
   }

   // New GPN format: regular string
   return parse_string(input, output, outlen);
 }

 unsigned char* parse_nvram(hnvram_format_e format, const char* input,
                            unsigned char* output, int* outlen) {
   output[0] = '\0';
   switch(format) {
     case HNVRAM_STRING:
       return parse_string(input, output, outlen);
       break;
     case HNVRAM_MAC:
       return parse_mac(input, output, outlen);
       break;
     case HNVRAM_HMXSWVERS:
       return parse_hmxswvers(input, output, outlen);
       break;
     case HNVRAM_UINT8:
       return parse_uint8(input, output, outlen);
       break;
     case HNVRAM_GPN:
       return parse_gpn(input, output, outlen);
       break;
     case HNVRAM_HEXSTRING:
       return parse_hexstring(input, output, outlen);
       break;
   }
   return NULL;
 }


 int write_nvram(char* optarg) {
   char* equal = strchr(optarg, '=');
   if (equal == NULL) {
     return -1;
   }

   char* name = optarg;
   *equal = '\0';
   char* value = ++equal;

   const hnvram_field_t* field = get_nvram_field(name);
   if (field == NULL) {
     return -2;
   }

   unsigned char nvram_value[NVRAM_MAX_DATA];
   int nvram_len = sizeof(nvram_value);
   if (parse_nvram(field->format, value, nvram_value, &nvram_len) == NULL) {
     return -3;
   }

   if (HMX_NVRAM_SetField(field->nvram_type, 0,
                          nvram_value, nvram_len) != DRV_OK) {
     return -4;
   }

   return 0;
 }

 int hnvram_main(int argc, char * const argv[]) {
   DRV_Error err;

   libupgrade_verbose = 0;

   if ((err = HMX_NVRAM_Init()) != DRV_OK) {
     fprintf(stderr, "NVRAM Init failed: %d\n", err);
     exit(1);
   }

   char op = 0;     // operation
   int op_cnt = 0;  // operation
   int q_flag = 0;  // quiet: don't output name of variable.
   int b_flag = 0;  // binary: output the binary format
   char output[NVRAM_MAX_DATA];
   int c;
   while ((c = getopt(argc, argv, "dbqrw:")) != -1) {
     switch(c) {
       case 'b':
         b_flag = 1;
         break;
       case 'q':
         q_flag = 1;
         break;
       case 'w':
         {
           char* duparg = strdup(optarg);
           if (write_nvram(duparg) != 0) {
             fprintf(stderr, "Unable to write %s\n", duparg);
             free(duparg);
             exit(1);
           }
           free(duparg);
         }
         break;
       case 'r':
       case 'd':
         if (op != c) {
           ++op_cnt;
         }
         op = c;
         break;
       default:
         usage(argv[0]);
         exit(1);
     }
   }

   if (op_cnt > 1) {
     usage(argv[0]);
     exit(1);
   }

   // dump NVRAM at the end, after all writes have been done.
   switch (op) {
     case 'd':
       if (optind < argc) {
         usage(argv[0]);
         exit(1);
       }
       if ((err = HMX_NVRAM_Dir()) != DRV_OK) {
         fprintf(stderr, "Unable to dump variables, HMX_NVRAM_Dir=%d\n", err);
       }
       break;
     case 'r':
       if (optind >= argc) {
         usage(argv[0]);
         exit(1);
       }
       for (; optind < argc; ++optind) {
         if (b_flag) {
           int len = read_raw_nvram(argv[optind], output, sizeof(output));
           if (len < 0) {
             fprintf(stderr, "Unable to read %s\n", argv[optind]);
             exit(1);
           }
           fwrite(output, 1, len, stdout);
         } else {
           if (read_nvram(argv[optind], output, sizeof(output), q_flag) == NULL) {
             fprintf(stderr, "Unable to read %s\n", argv[optind]);
             exit(1);
           }
           puts(output);
         }
       }
       break;
   }

   exit(0);
 }

 #ifndef TEST_MAIN
 int main(int argc, char * const argv[]) {
   return hnvram_main(argc, argv);
 }
 #endif  // TEST_MAIN
	// Copyright 2011 Google Inc. All Rights Reserved.
	// Author: dgentry@google.com (Denny Gentry)

	#define _GNU_SOURCE
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	#include "hmx_upgrade_nvram.h"

	// Max length of data in an NVRAM field
	#define NVRAM_MAX_DATA 4096

	// Number of bytes of GPN to be represented as hex data
	#define GPN_HEX_BYTES 4

	/* To avoid modifying the HMX code, we supply dummy versions of two
	* missing routines to satisfy the linker. These are used when writing
	* the complete NVRAM partiton, which we do not need in this utility. */
	DRV_Error DRV_NANDFLASH_GetNvramHandle(int handle) {
	return DRV_ERR;
	}
	DRV_Error DRV_FLASH_Write(int offset, char *data, int nDataSize) {
	return DRV_ERR;
	}

	void usage(const char* progname) {
	printf("Usage: %s [-d \| [-q\|-b] -r VARNAME] [-w VARNAME=value]\n", progname);
	printf("\t-d : dump all NVRAM variables\n");
	printf("\t-r VARNAME : read VARNAME from NVRAM\n");
	printf("\t-q : quiet mode, suppress the variable name and equal sign\n");
	printf("\t-b : read VARNAME from NVRAM in raw binary format, e.g. dumping a binary key\n");
	printf("\t-w VARNAME=value : write value to VARNAME in NVRAM.\n");
	}

	// Format of data in the NVRAM
	typedef enum {
	HNVRAM_STRING, // NUL-terminated string
	HNVRAM_MAC, // 00:11:22:33:44:55
	HNVRAM_HMXSWVERS, // 2.15
	HNVRAM_UINT8, // a single byte, generally 0/1 for a boolean.
	HNVRAM_GPN, // Two formats:
	// - 4 bytes (old format): printed as 8 digit hex.
	// - > 4 bytes (new format): printed as NULL-terminated
	// string.
	HNVRAM_HEXSTRING // hexbinary
	} hnvram_format_e;

	typedef struct hnvram_field_s {
	const char* name;
	NVRAM_FIELD_T nvram_type; // defined in hmx_upgrade_nvram.h
	hnvram_format_e format;
	} hnvram_field_t;

	const hnvram_field_t nvram_fields[] = {
	{"SYSTEM_ID", NVRAM_FIELD_SYSTEM_ID, HNVRAM_STRING},
	{"MAC_ADDR", NVRAM_FIELD_MAC_ADDR, HNVRAM_MAC},
	{"SERIAL_NO", NVRAM_FIELD_SERIAL_NO, HNVRAM_STRING},
	{"LOADER_VERSION", NVRAM_FIELD_LOADER_VERSION, HNVRAM_HMXSWVERS},
	{"ACTIVATED_KERNEL_NUM", NVRAM_FIELD_ACTIVATED_KERNEL_NUM, HNVRAM_UINT8},
	{"MTD_TYPE_FOR_KERNEL", NVRAM_FIELD_MTD_TYPE_FOR_KERNEL, HNVRAM_STRING},
	{"ACTIVATED_KERNEL_NAME", NVRAM_FIELD_ACTIVATED_KERNEL_NAME, HNVRAM_STRING},
	{"EXTRA_KERNEL_OPT", NVRAM_FIELD_EXTRA_KERNEL_OPT, HNVRAM_STRING},
	{"PLATFORM_NAME", NVRAM_FIELD_PLATFORM_NAME, HNVRAM_STRING},
	{"1ST_SERIAL_NUMBER", NVRAM_FIELD_1ST_SERIAL_NUMBER, HNVRAM_STRING},
	{"2ND_SERIAL_NUMBER", NVRAM_FIELD_2ND_SERIAL_NUMBER, HNVRAM_STRING},
	{"GPN", NVRAM_FIELD_GPN, HNVRAM_GPN},
	{"MAC_ADDR_MOCA", NVRAM_FIELD_MAC_ADDR_MOCA, HNVRAM_MAC},
	{"MAC_ADDR_BT", NVRAM_FIELD_MAC_ADDR_BT, HNVRAM_MAC},
	{"MAC_ADDR_WIFI", NVRAM_FIELD_MAC_ADDR_WIFI, HNVRAM_MAC},
	{"MAC_ADDR_WIFI2", NVRAM_FIELD_MAC_ADDR_WIFI2, HNVRAM_MAC},
	{"MAC_ADDR_WAN", NVRAM_FIELD_MAC_ADDR_WAN, HNVRAM_MAC},
	{"HDCP_KEY", NVRAM_FIELD_HDCP_KEY, HNVRAM_HEXSTRING},
	{"DTCP_KEY", NVRAM_FIELD_DTCP_KEY, HNVRAM_HEXSTRING},
	{"GOOGLE_SSL_PEM", NVRAM_FIELD_GOOGLE_SSL_PEM, HNVRAM_STRING},
	{"GOOGLE_SSL_CRT", NVRAM_FIELD_GOOGLE_SSL_CRT, HNVRAM_STRING},
	{"PAIRED_DISK", NVRAM_FIELD_PAIRED_DISK, HNVRAM_STRING},
	{"PARTITION_VER", NVRAM_FIELD_PARTITION_VER, HNVRAM_STRING},
	{"HW_VER", NVRAM_FIELD_HW_VER, HNVRAM_UINT8},
	{"UITYPE", NVRAM_FIELD_UITYPE, HNVRAM_STRING},
	{"LASER_CHANNEL", NVRAM_FIELD_LASER_CHANNEL, HNVRAM_STRING},
	{"MAC_ADDR_PON", NVRAM_FIELD_MAC_ADDR_PON, HNVRAM_MAC},
	{"PRODUCTION_UNIT", NVRAM_FIELD_PRODUCTION_UNIT, HNVRAM_STRING},
	{"BOOT_TARGET", NVRAM_FIELD_BOOT_TARGET, HNVRAM_STRING},
	};

	const hnvram_field_t* get_nvram_field(const char* name) {
	int nentries = sizeof(nvram_fields) / sizeof(nvram_fields[0]);
	int i;

	for (i = 0; i < nentries; ++i) {
	const hnvram_field_t* map = &nvram_fields[i];
	if (strcasecmp(name, map->name) == 0) {
	return map;
	}
	}

	return NULL;
	}


	// ------------------ READ NVRAM -----------------------------


	void format_string(const char* data, char* output, int outlen) {
	snprintf(output, outlen, "%s", data);
	}

	void format_mac(const char* data, char* output, int outlen) {
	const unsigned char* mac = (const unsigned char*) data;
	snprintf(output, outlen, "%02hx:%02hx:%02hx:%02hx:%02hx:%02hx",
	mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
	}

	void format_hmxswvers(const char* data, char* output, int outlen) {
	const unsigned char* udata = (const unsigned char*) data;
	snprintf(output, outlen, "%hhu.%hhu", udata[1], udata[0]);
	}

	void format_uint8(const char* data, char* output, int outlen) {
	const unsigned char* d = (const unsigned char*)data;
	snprintf(output, outlen, "%u", d[0]);
	}

	void format_hexstring(const char* data, int datalen, char* output, int outlen) {
	const unsigned char* d = (const unsigned char*)data;
	int i;
	if (outlen < (datalen * 2 + 1)) {
	fprintf(stderr, "%s buffer too small %d < %d",
	__FUNCTION__, outlen, (datalen * 2 + 1));
	exit(1);
	}
	for (i = 0; i < datalen; ++i) {
	snprintf(output + (i * 2), 3, "%02x", d[i]);
	}
	}

	void format_gpn(const char* data, const int data_len, char* output,
	int outlen) {
	// Format first 4 bytes as 8 digit hex.
	if (data_len == GPN_HEX_BYTES)
	format_hexstring(data, GPN_HEX_BYTES, output, outlen);
	else
	format_string(data, output, outlen);
	}

	char* format_nvram(hnvram_format_e format, const char* data,
	const int data_len, char* output, int outlen) {
	output[0] = '\0';
	switch(format) {
	case HNVRAM_STRING: format_string(data, output, outlen); break;
	case HNVRAM_MAC: format_mac(data, output, outlen); break;
	case HNVRAM_HMXSWVERS: format_hmxswvers(data, output, outlen); break;
	case HNVRAM_UINT8: format_uint8(data, output, outlen); break;
	case HNVRAM_GPN: format_gpn(data, data_len, output, outlen); break;
	case HNVRAM_HEXSTRING: format_hexstring(data, data_len, output, outlen);
	break;
	}
	return output;
	}

	int read_raw_nvram(const char* name, char* output, int outlen) {
	const hnvram_field_t* field = get_nvram_field(name);
	int ret;
	if (field == NULL) {
	return -1;
	}

	if (HMX_NVRAM_GetLength(field->nvram_type, &ret) != DRV_OK) {
	return -1;
	}

	if (ret > outlen) {
	return -1;
	}

	if (HMX_NVRAM_GetField(field->nvram_type, 0, output, outlen) != DRV_OK) {
	return -1;
	}

	return ret;
	}

	char* read_nvram(const char* name, char* output, int outlen, int quiet) {
	const hnvram_field_t* field = get_nvram_field(name);
	if (field == NULL) {
	return NULL;
	}

	char data[NVRAM_MAX_DATA] = {0};
	int data_len = 0;
	if (HMX_NVRAM_GetField(field->nvram_type, 0, data, sizeof(data)) != DRV_OK \|\|
	HMX_NVRAM_GetLength(field->nvram_type, &data_len) != DRV_OK) {
	return NULL;
	}
	char formatbuf[NVRAM_MAX_DATA * 2];
	char* nv = format_nvram(field->format, data, data_len, formatbuf, sizeof(formatbuf));
	if (quiet) {
	snprintf(output, outlen, "%s", nv);
	} else {
	snprintf(output, outlen, "%s=%s", name, nv);
	}
	return output;
	}


	// ----------------- WRITE NVRAM -----------------------------


	unsigned char* parse_string(const char* input,
	unsigned char* output, int* outlen) {
	int len = strlen(input);
	if (len > *outlen) {
	len = *outlen;
	}

	strncpy((char*)output, input, len);
	*outlen = len;
	return output;
	}

	unsigned char* parse_mac(const char* input,
	unsigned char* output, int* outlen) {
	if (*outlen < 6) return NULL;

	if (sscanf(input, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx",
	&output[0], &output[1], &output[2],
	&output[3], &output[4], &output[5]) != 6) {
	return NULL;
	}
	*outlen = 6;
	return output;
	}

	unsigned char* parse_hmxswvers(const char* input,
	unsigned char* output, int* outlen) {
	if (*outlen < 2) return NULL;

	if (sscanf(input, "%hhd.%hhd", &output[1], &output[0]) != 2) {
	return NULL;
	}
	*outlen = 2;
	return output;
	}

	unsigned char* parse_uint8(const char* input,
	unsigned char* output, int* outlen) {
	if (*outlen < 1) return NULL;

	output[0] = input[0] - '0';
	*outlen = 1;
	return output;
	}

	int parse_hexdigit(unsigned char c) {
	switch(c) {
	case '0' ... '9': return c - '0';
	case 'a' ... 'f': return 10 + (c - 'a');
	case 'A' ... 'F': return 10 + (c - 'A');
	default: return 0xff;
	}
	}

	unsigned char* parse_hexstring(const char* input,
	unsigned char* output, int* outlen) {
	int i, len = strlen(input) / 2;
	if (*outlen < len) {
	len = *outlen;
	}

	for (i = 0; i < len; ++i) {
	unsigned char c;
	output[i] = parse_hexdigit(input[2*i]) << 4 \|
	parse_hexdigit(input[2*i+1]);
	}

	*outlen = len;
	return output;
	}

	int is_hexstring(const char* input, int hex_len) {
	int i = 0;
	for (i = 0; i < hex_len; i++) {
	if (!isxdigit(input[i])) {
	return 0;
	}
	}
	if (input[hex_len] != '\0') {
	return 0;
	}
	return 1;
	}

	unsigned char* parse_gpn(const char* input,
	unsigned char* output, int* outlen) {
	if (*outlen < 4) return NULL;

	// Old GPN format: 8-digit hex string
	if (is_hexstring(input, GPN_HEX_BYTES * 2)) {
	if (sscanf(input, "%02hhx%02hhx%02hhx%02hhx",
	&output[0], &output[1], &output[2], &output[3]) != GPN_HEX_BYTES) {
	return NULL;
	}
	*outlen = GPN_HEX_BYTES;
	return output;
	}

	// New GPN format: regular string
	return parse_string(input, output, outlen);
	}

	unsigned char* parse_nvram(hnvram_format_e format, const char* input,
	unsigned char* output, int* outlen) {
	output[0] = '\0';
	switch(format) {
	case HNVRAM_STRING:
	return parse_string(input, output, outlen);
	break;
	case HNVRAM_MAC:
	return parse_mac(input, output, outlen);
	break;
	case HNVRAM_HMXSWVERS:
	return parse_hmxswvers(input, output, outlen);
	break;
	case HNVRAM_UINT8:
	return parse_uint8(input, output, outlen);
	break;
	case HNVRAM_GPN:
	return parse_gpn(input, output, outlen);
	break;
	case HNVRAM_HEXSTRING:
	return parse_hexstring(input, output, outlen);
	break;
	}
	return NULL;
	}


	int write_nvram(char* optarg) {
	char* equal = strchr(optarg, '=');
	if (equal == NULL) {
	return -1;
	}

	char* name = optarg;
	*equal = '\0';
	char* value = ++equal;

	const hnvram_field_t* field = get_nvram_field(name);
	if (field == NULL) {
	return -2;
	}

	unsigned char nvram_value[NVRAM_MAX_DATA];
	int nvram_len = sizeof(nvram_value);
	if (parse_nvram(field->format, value, nvram_value, &nvram_len) == NULL) {
	return -3;
	}

	if (HMX_NVRAM_SetField(field->nvram_type, 0,
	nvram_value, nvram_len) != DRV_OK) {
	return -4;
	}

	return 0;
	}

	int hnvram_main(int argc, char * const argv[]) {
	DRV_Error err;

	libupgrade_verbose = 0;

	if ((err = HMX_NVRAM_Init()) != DRV_OK) {
	fprintf(stderr, "NVRAM Init failed: %d\n", err);
	exit(1);
	}

	char op = 0; // operation
	int op_cnt = 0; // operation
	int q_flag = 0; // quiet: don't output name of variable.
	int b_flag = 0; // binary: output the binary format
	char output[NVRAM_MAX_DATA];
	int c;
	while ((c = getopt(argc, argv, "dbqrw:")) != -1) {
	switch(c) {
	case 'b':
	b_flag = 1;
	break;
	case 'q':
	q_flag = 1;
	break;
	case 'w':
	{
	char* duparg = strdup(optarg);
	if (write_nvram(duparg) != 0) {
	fprintf(stderr, "Unable to write %s\n", duparg);
	free(duparg);
	exit(1);
	}
	free(duparg);
	}
	break;
	case 'r':
	case 'd':
	if (op != c) {
	++op_cnt;
	}
	op = c;
	break;
	default:
	usage(argv[0]);
	exit(1);
	}
	}

	if (op_cnt > 1) {
	usage(argv[0]);
	exit(1);
	}

	// dump NVRAM at the end, after all writes have been done.
	switch (op) {
	case 'd':
	if (optind < argc) {
	usage(argv[0]);
	exit(1);
	}
	if ((err = HMX_NVRAM_Dir()) != DRV_OK) {
	fprintf(stderr, "Unable to dump variables, HMX_NVRAM_Dir=%d\n", err);
	}
	break;
	case 'r':
	if (optind >= argc) {
	usage(argv[0]);
	exit(1);
	}
	for (; optind < argc; ++optind) {
	if (b_flag) {
	int len = read_raw_nvram(argv[optind], output, sizeof(output));
	if (len < 0) {
	fprintf(stderr, "Unable to read %s\n", argv[optind]);
	exit(1);
	}
	fwrite(output, 1, len, stdout);
	} else {
	if (read_nvram(argv[optind], output, sizeof(output), q_flag) == NULL) {
	fprintf(stderr, "Unable to read %s\n", argv[optind]);
	exit(1);
	}
	puts(output);
	}
	}
	break;
	}

	exit(0);
	}

	#ifndef TEST_MAIN
	int main(int argc, char * const argv[]) {
	return hnvram_main(argc, argv);
	}
	#endif // TEST_MAIN