Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 39cc3e70 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

bootstat: allow kernel_panic,sysrq to propagate subreason 

Allow for a daemon to write to last kmsg to propagate a detailed
subreason to kernel_panic,sysrq actions.  A minor refactor moves
common code into a helper function getSubreason for retrieval and
bit error correction operations.

A sysrq crash generally produces a kernel-provided message:
    SysRq : Trigger a crash
which is used to generate a canonical boot reason kernel_panic,sysrq.
A user daemon could write to /dev/kmsg just prior to the sysrq with
    SysRq : Trigger a crash : '<subreason>'
to change the canonical boot reason to kernel_panic,sysrq,<subreason>.

Administration added pending kBootReasonMap entries present in TRON.

Test: manual echo into /dev/kmsg and /proc/sysrq-trigger and check
Test: boot_reason_test.sh
Bug: 33808187
Bug: 63736262
Change-Id: Ibf5432737e5a3449ebe40a8c6cf2d3e912ed6bbc
parent 855d2058

bootstat/bootstat.cpp

+56 −35
Original line number Diff line number Diff line
@@ -291,6 +291,10 @@ const std::map<std::string, int32_t> kBootReasonMap = { 
    {"software_master", 147},

    {"cold,charger", 148},

    {"cold,rtc", 149},

    {"cold,rtc,2sec", 150},

    {"reboot,tool", 151},

    {"reboot,wdt", 152},

    {"reboot,unknown", 153},

};



// Converts a string value representing the reason the system booted to an
@@ -467,6 +471,8 @@ class pstoreConsole { 
    }

    return std::string::npos;

  }



  operator const std::string&() const { return console; }

};



// If bit error match to needle, correct it.
@@ -503,12 +509,60 @@ bool correctForBitErrorOrUnderline(std::string& reason, const std::string& needl 
  return corrected;

}



// Converts a string value representing the reason the system booted to a

// string complying with Android system standard reason.

void transformReason(std::string& reason) {

  std::transform(reason.begin(), reason.end(), reason.begin(), ::tolower);

  std::transform(reason.begin(), reason.end(), reason.begin(),

                 [](char c) { return ::isblank(c) ? '_' : c; });

  std::transform(reason.begin(), reason.end(), reason.begin(),

                 [](char c) { return ::isprint(c) ? c : '?'; });

}



// Pull out and correct quoted (') subreason, pos just beyond first quote.

// Check subreasons for reboot,<subreason> and kernel_panic,sysrq,<subreason>

std::string getSubreason(const std::string& content, size_t pos) {

  static constexpr size_t max_reason_length = 256;



  std::string subReason(content.substr(pos, max_reason_length));

  // Correct against any known strings that Bit Error Match

  for (const auto& s : knownReasons) {

    correctForBitErrorOrUnderline(subReason, s);

  }

  for (const auto& m : kBootReasonMap) {

    if (m.first.length() <= strlen("cold")) continue;  // too short?

    if (correctForBitErrorOrUnderline(subReason, m.first + "'")) continue;

    if (m.first.length() <= strlen("reboot,cold")) continue;  // short?

    if (android::base::StartsWith(m.first, "reboot,")) {

      correctForBitErrorOrUnderline(subReason, m.first.substr(strlen("reboot,")) + "'");

    } else if (android::base::StartsWith(m.first, "kernel_panic,sysrq,")) {

      correctForBitErrorOrUnderline(subReason, m.first.substr(strlen("kernel_panic,sysrq,")) + "'");

    }

  }

  for (pos = 0; pos < subReason.length(); ++pos) {

    char c = subReason[pos];

    // #, &, %, / are common single bit error for ' that we can block

    if (!::isprint(c) || (c == '\'') || (c == '#') || (c == '&') || (c == '%') || (c == '/')) {

      subReason.erase(pos);

      break;

    }

  }

  transformReason(subReason);

  return subReason;

}



bool addKernelPanicSubReason(const pstoreConsole& console, std::string& ret) {

  // Check for kernel panic types to refine information

  if ((console.rfind("SysRq : Trigger a crash") != std::string::npos) ||

      (console.rfind("PC is at sysrq_handle_crash+") != std::string::npos)) {

    // Can not happen, except on userdebug, during testing/debugging.

    ret = "kernel_panic,sysrq";

    // Invented for Android to allow daemons that specifically trigger sysrq

    // to communicate more accurate boot subreasons via last console messages.

    static constexpr char sysrqSubreason[] = "SysRq : Trigger a crash : '";

    auto pos = console.rfind(sysrqSubreason);

    if (pos != std::string::npos) {

      ret += "," + getSubreason(console, pos + strlen(sysrqSubreason));

    }

    return true;

  }

  if (console.rfind("Unable to handle kernel NULL pointer dereference at virtual address") !=
@@ -527,24 +581,12 @@ bool addKernelPanicSubReason(const std::string& content, std::string& ret) { 
  return addKernelPanicSubReason(pstoreConsole(content), ret);

}



// Converts a string value representing the reason the system booted to a

// string complying with Android system standard reason.

void transformReason(std::string& reason) {

  std::transform(reason.begin(), reason.end(), reason.begin(), ::tolower);

  std::transform(reason.begin(), reason.end(), reason.begin(),

                 [](char c) { return ::isblank(c) ? '_' : c; });

  std::transform(reason.begin(), reason.end(), reason.begin(),

                 [](char c) { return ::isprint(c) ? c : '?'; });

}



const char system_reboot_reason_property[] = "sys.boot.reason";

const char last_reboot_reason_property[] = LAST_REBOOT_REASON_PROPERTY;

const char bootloader_reboot_reason_property[] = "ro.boot.bootreason";



// Scrub, Sanitize, Standardize and Enhance the boot reason string supplied.

std::string BootReasonStrToReason(const std::string& boot_reason) {

  static const size_t max_reason_length = 256;



  std::string ret(GetProperty(system_reboot_reason_property));

  std::string reason(boot_reason);

  // If sys.boot.reason == ro.boot.bootreason, let's re-evaluate
@@ -647,28 +689,7 @@ std::string BootReasonStrToReason(const std::string& boot_reason) { 
      static const char cmd[] = "reboot: Restarting system with command '";

      size_t pos = console.rfind(cmd);

      if (pos != std::string::npos) {

        pos += strlen(cmd);

        std::string subReason(content.substr(pos, max_reason_length));

        // Correct against any known strings that Bit Error Match

        for (const auto& s : knownReasons) {

          correctForBitErrorOrUnderline(subReason, s);

        }

        for (const auto& m : kBootReasonMap) {

          if (m.first.length() <= strlen("cold")) continue;  // too short?

          if (correctForBitErrorOrUnderline(subReason, m.first + "'")) continue;

          if (m.first.length() <= strlen("reboot,cold")) continue;  // short?

          if (!android::base::StartsWith(m.first, "reboot,")) continue;

          correctForBitErrorOrUnderline(subReason, m.first.substr(strlen("reboot,")) + "'");

        }

        for (pos = 0; pos < subReason.length(); ++pos) {

          char c = subReason[pos];

          // #, &, %, / are common single bit error for ' that we can block

          if (!::isprint(c) || (c == '\'') || (c == '#') || (c == '&') || (c == '%') || (c == '/')) {

            subReason.erase(pos);

            break;

          }

        }

        transformReason(subReason);

        std::string subReason(getSubreason(content, pos + strlen(cmd)));

        if (subReason != "") {  // Will not land "reboot" as that is too blunt.

          if (isKernelRebootReason(subReason)) {

            ret = "reboot," + subReason;  // User space can't talk kernel reasons.