add c++ version of the firmware utilities

reboot_mode.cc

+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// NOTE: this file is translated from reboot_mode.py
+//
+// A script to manipulate ChromeOS CMOS reboot Field.
+//
+// A few bits in a byte in CMOS (called RDB, short for 'Reboot Data Byte'
+// hereafter) are dedicated to information exchange between Linux and BIOS.
+//
+// The CMOS contents are available through /dev/nvrom. The location of RDB is
+// reported by BIOS through ACPI. The few bits in RDB operated on by this script
+// are defined in the all_mode_fields dictionary below along with their
+// functions.
+//
+// When invoked without parameters this script prints values of the fields. When
+// invoked with any of the bit field names as parameter(s), the script sets the
+// bit(s) as required.
+//
+// Additional parameters allow to specify alternative ACPI and NVRAM files for
+// testing.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <sys/param.h>
+#include <stdint.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <getopt.h>
+
+#include <string>
+#include <algorithm>
+#include <vector>
+#include <map>
+
+#define DEFAULT_ACPI_FILE       "/sys/devices/platform/chromeos_acpi/CHNV"
+#define DEFAULT_NVRAM_FILE      "/dev/nvram"
+
+///////////////////////////////////////////////////////////////////////
+// Utilities for quick python-C translation
+
+using std::string;
+
+// Works like throwing an exception - directly exit here.
+static void RebootModeError(const char *message, ...) {
+  va_list args;
+  va_start(args, message);
+  vfprintf(stderr, message, args);
+  fprintf(stderr, "\n");
+  va_end(args);
+  exit(1);
+}
+
+// return a string which is upper case of input parameter.
+static string str_to_upper(const string str) {
+  string newstr = str;
+  std::transform(str.begin(), str.end(), newstr.begin(), toupper);
+  return newstr;
+}
+
+///////////////////////////////////////////////////////////////////////
+
+typedef std::map<string, uint8_t> RDB_BitField;
+
+struct RebootModeConfig {
+  // file path
+  string acpi_file;
+  string nvram_file;
+
+  // Offset of RDB in NVRAM
+  int rdb_offset;
+
+  // NVRAM contents read on startup
+  uint8_t rdb_value;
+
+  // A dictionary of fields to be updated as requested by the command line
+  // parameters
+  RDB_BitField fields_to_set;
+
+  // All bitfields in RDB this script provides access to. Field names prepended
+  // by `--' become this script's command line options
+  RDB_BitField all_mode_fields;
+
+  // write constructure here to ease python translation
+  RebootModeConfig() {
+    acpi_file = DEFAULT_ACPI_FILE;
+    nvram_file = DEFAULT_NVRAM_FILE;
+    rdb_offset = 0;
+    all_mode_fields["recovery"] = 0x80;
+    all_mode_fields["debug_reset"] = 0x40;
+    all_mode_fields["try_firmware_b"] = 0x20;
+  }
+} cfg;  // this is a special global object to ease python translation.
+
+// Process bit field name command line parameter.
+//
+// Verifies that the value is in range (0 or 1) and adds the appropriate
+// element to fields_to_set dictionary. Should the same field specified in the
+// command line more than once, only the last value will be used.
+//
+// Raises:
+//   RebootModeError in case the parameter value is out of range.
+void OptionHandler(const char *opt_str, const char *value_str) {
+  const char *key = opt_str;
+  int value = atoi(value_str);
+
+  if (!value && *value_str != '0')
+    RebootModeError("--%s needs numeric argument value", key);
+
+  if (value < 0 || value > 1)
+    RebootModeError("--%s should be either 0 or 1", key);
+
+  if (cfg.all_mode_fields.find(key) == cfg.all_mode_fields.end())
+    RebootModeError("INTERNAL ERROR: UNKNOWN FIELD: %s", key);
+
+  cfg.fields_to_set[key] = value;
+}
+
+void GetRDBOffset() {
+  const char *acpi_file = cfg.acpi_file.c_str();
+
+  FILE *f = fopen(acpi_file, "rb");
+  if (!f) {
+    perror(acpi_file);
+    RebootModeError("Cannot read acpi_file: %s", acpi_file);
+  }
+
+  char buffer[PATH_MAX];  // this should be large enough
+  if (fgets(buffer, sizeof(buffer), f) == NULL) {
+    perror(acpi_file);
+    RebootModeError("Trying to read %s but failed.", acpi_file);
+  }
+
+  cfg.rdb_offset = atoi(buffer);
+  if (!cfg.rdb_offset && *buffer != '0') {  // consider this as error
+    RebootModeError("%s contents are corrupted", acpi_file);
+  }
+}
+
+void ReadNvram() {
+  FILE *f = fopen(cfg.nvram_file.c_str(), "rb");
+  if (!f) {
+    if (errno == 2)
+      RebootModeError("%s does not exist. Is nvram module installed?",
+                      cfg.nvram_file.c_str());
+    if (errno == 13)
+      RebootModeError("Access to %s denied. Are you root?",
+                      cfg.nvram_file.c_str());
+    // all other error
+    perror(cfg.nvram_file.c_str());
+  }
+
+  if (fseek(f, cfg.rdb_offset, SEEK_SET) == -1 ||
+      fread(&cfg.rdb_value, 1, 1, f) != 1) {
+    perror(cfg.nvram_file.c_str());
+    RebootModeError("Failed reading mode byte from %s", cfg.nvram_file.c_str());
+  }
+  fclose(f);
+}
+
+void PrintCurrentMode() {
+  printf("Current reboot mode settings:\n");
+  for (RDB_BitField::iterator i = cfg.all_mode_fields.begin();
+       i != cfg.all_mode_fields.end();
+       ++i) {
+    printf("%-15s: %d\n", i->first.c_str(),
+           (cfg.rdb_value & i->second) ? 1 : 0);
+  }
+}
+
+void SetNewMode() {
+  uint8_t new_mode = 0;
+  uint8_t updated_bits_mask = 0;
+
+  for (RDB_BitField::iterator i = cfg.fields_to_set.begin();
+       i != cfg.fields_to_set.end();
+       ++i) {
+    string opt = i->first;
+    uint8_t value = i->second;
+    assert(cfg.all_mode_fields.find(opt) != cfg.all_mode_fields.end());
+
+    uint8_t mask = cfg.all_mode_fields[opt];
+    if (value)
+      new_mode |= mask;
+
+    updated_bits_mask |= mask;
+  }
+
+  if ((cfg.rdb_value & updated_bits_mask) == new_mode) {
+    printf("No update required\n");
+    return;
+  }
+
+  FILE *f = fopen(cfg.nvram_file.c_str(), "rb+");
+  fseek(f, cfg.rdb_offset, SEEK_SET);
+  new_mode |= (cfg.rdb_value & ~updated_bits_mask);
+  if (fwrite(&new_mode, 1, 1, f) != 1) {
+    RebootModeError("Failed writing mode byte to %s", cfg.nvram_file.c_str());
+  }
+  fclose(f);
+}
+
+const char *__name__;
+
+void usage_help_exit(int err) {
+  printf("Usage: %s [options]\n"
+         "\n"
+         "Options:\n"
+         "  -h, --help\t\tshow this help message and exit\n"
+         "  --acpi_file=ACPI_FILE\n"
+         "  --nvram_file=NVRAM_FILE\n"
+         , __name__);
+
+  // list all possible fields
+  for (RDB_BitField::iterator i = cfg.all_mode_fields.begin();
+       i != cfg.all_mode_fields.end();
+       ++i) {
+    printf("  --%s=%s\n",
+           i->first.c_str(),
+           str_to_upper(i->first).c_str());
+  }
+  exit(err);
+}
+
+int main(int argc, char *argv[]) {
+  __name__ = argv[0];
+
+  struct option optv = {0};
+  std::vector<struct option> longopts;
+  int max_field_index = 0;
+
+  optv.has_arg = 0;
+  optv.val = 0;
+  optv.name = "help";           // value = 0
+  longopts.push_back(optv);
+  optv.has_arg = 1;
+
+  optv.val++;
+  optv.name = "acpi_file";      // value = 1
+  longopts.push_back(optv);
+  optv.val++;
+  optv.name = "nvram_file";     // value = 2
+  longopts.push_back(optv);
+
+  // add all known RDB fields
+  for (RDB_BitField::iterator i = cfg.all_mode_fields.begin();
+       i != cfg.all_mode_fields.end();
+       ++i) {
+    optv.name = i->first.c_str();
+    optv.val++;
+    longopts.push_back(optv);
+  }
+  max_field_index = optv.val;
+
+  // add a zero for closing options
+  optv.name = NULL;
+  optv.val = optv.has_arg = 0;
+  longopts.push_back(optv);
+
+  int optc;
+  while ((optc = getopt_long(argc, argv, "h", &longopts.front(), NULL)) != -1) {
+    switch (optc) {
+      case 1:
+        cfg.acpi_file = optarg;
+        break;
+
+      case 2:
+        cfg.nvram_file = optarg;
+        break;
+
+      default:
+        // RDB fields?
+        // printf("optc: %d %s %s\n", optc, longopts[optc].name, optarg);
+        if (optc > 0 && optc <= max_field_index)
+          OptionHandler(longopts[optc].name, optarg);
+        else
+          usage_help_exit(1);
+        break;
+    }
+  }
+
+  // currently no other non-dashed arguments allowed.
+  if (optind != argc)
+    usage_help_exit(1);
+
+  GetRDBOffset();
+  ReadNvram();
+
+  if (!cfg.fields_to_set.empty()) {
+    SetNewMode();
+  } else {
+    PrintCurrentMode();
+  }
+  return 0;
+}