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Commit ebc8fe19 authored by David Anderson's avatar David Anderson
Browse files

fastboot: Add a command to get current kernel logs. 

This adds "fastboot getvar dmesg", usable only in userspace fastboot,
and only on unlocked devices. This is to debug flashing failures when
serial log access is not available.

Bug: 230269532
Test: fastboot getvar dmesg
Change-Id: Ic57881e362efe3f0687f41ab986d30b3a59dc4e4
parent cef4850d

fastboot/constants.h

+1 −0
Original line number Diff line number Diff line
@@ -79,3 +79,4 @@ 
#define FB_VAR_SECURITY_PATCH_LEVEL "security-patch-level"

#define FB_VAR_TREBLE_ENABLED "treble-enabled"

#define FB_VAR_MAX_FETCH_SIZE "max-fetch-size"

#define FB_VAR_DMESG "dmesg"

fastboot/device/commands.cpp

+54 −41
Original line number Diff line number Diff line
@@ -112,7 +112,6 @@ static void GetAllVars(FastbootDevice* device, const std::string& name, 
    }

}



bool GetVarHandler(FastbootDevice* device, const std::vector<std::string>& args) {

const std::unordered_map<std::string, VariableHandlers> kVariableMap = {

        {FB_VAR_VERSION, {GetVersion, nullptr}},

        {FB_VAR_VERSION_BOOTLOADER, {GetBootloaderVersion, nullptr}},
@@ -150,14 +149,28 @@ bool GetVarHandler(FastbootDevice* device, const std::vector<std::string>& args) 
        {FB_VAR_MAX_FETCH_SIZE, {GetMaxFetchSize, nullptr}},

};



static bool GetVarAll(FastbootDevice* device) {

    for (const auto& [name, handlers] : kVariableMap) {

        GetAllVars(device, name, handlers);

    }

    return true;

}



const std::unordered_map<std::string, std::function<bool(FastbootDevice*)>> kSpecialVars = {

        {"all", GetVarAll},

        {"dmesg", GetDmesg},

};



bool GetVarHandler(FastbootDevice* device, const std::vector<std::string>& args) {

    if (args.size() < 2) {

        return device->WriteFail("Missing argument");

    }



    // Special case: return all variables that we can.

    if (args[1] == "all") {

        for (const auto& [name, handlers] : kVariableMap) {

            GetAllVars(device, name, handlers);

    // "all" and "dmesg" are multiline and handled specially.

    auto found_special = kSpecialVars.find(args[1]);

    if (found_special != kSpecialVars.end()) {

        if (!found_special->second(device)) {

            return false;

        }

        return device->WriteOkay("");

    }

fastboot/device/variables.cpp

+36 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include "variables.h"



#include <inttypes.h>

#include <stdio.h>



#include <android-base/file.h>

#include <android-base/logging.h>
@@ -28,6 +29,7 @@ 
#include <fs_mgr.h>

#include <liblp/liblp.h>



#include "constants.h"

#include "fastboot_device.h"

#include "flashing.h"

#include "utility.h"
@@ -46,6 +48,7 @@ using ::android::hardware::fastboot::V1_0::Result; 
using ::android::hardware::fastboot::V1_0::Status;

using IBootControl1_1 = ::android::hardware::boot::V1_1::IBootControl;

using namespace android::fs_mgr;

using namespace std::string_literals;



constexpr char kFastbootProtocolVersion[] = "0.4";
@@ -518,3 +521,36 @@ bool GetMaxFetchSize(FastbootDevice* /* device */, const std::vector<std::string 
    *message = android::base::StringPrintf("0x%X", kMaxFetchSizeDefault);

    return true;

}



bool GetDmesg(FastbootDevice* device) {

    if (GetDeviceLockStatus()) {

        return device->WriteFail("Cannot use when device flashing is locked");

    }



    std::unique_ptr<FILE, decltype(&::fclose)> fp(popen("/system/bin/dmesg", "re"), ::fclose);

    if (!fp) {

        PLOG(ERROR) << "popen /system/bin/dmesg";

        return device->WriteFail("Unable to run dmesg: "s + strerror(errno));

    }



    ssize_t rv;

    size_t n = 0;

    char* str = nullptr;

    while ((rv = ::getline(&str, &n, fp.get())) > 0) {

        if (str[rv - 1] == '\n') {

            rv--;

        }

        device->WriteInfo(std::string(str, rv));

    }



    int saved_errno = errno;

    ::free(str);



    if (rv < 0 && saved_errno) {

        LOG(ERROR) << "dmesg getline: " << strerror(saved_errno);

        device->WriteFail("Unable to read dmesg: "s + strerror(saved_errno));

        return false;

    }



    return true;

}

fastboot/device/variables.h

+3 −0
Original line number Diff line number Diff line
@@ -83,6 +83,9 @@ bool GetTrebleEnabled(FastbootDevice* device, const std::vector<std::string>& ar 
bool GetMaxFetchSize(FastbootDevice* /* device */, const std::vector<std::string>& /* args */,

                     std::string* message);



// Complex cases.

bool GetDmesg(FastbootDevice* device);



// Helpers for getvar all.

std::vector<std::vector<std::string>> GetAllPartitionArgsWithSlot(FastbootDevice* device);

std::vector<std::vector<std::string>> GetAllPartitionArgsNoSlot(FastbootDevice* device);