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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "firmware_handler.h"
     18 
     19 #include <fcntl.h>
     20 #include <sys/sendfile.h>
     21 #include <sys/wait.h>
     22 #include <unistd.h>
     23 
     24 #include <string>
     25 #include <thread>
     26 
     27 #include <android-base/chrono_utils.h>
     28 #include <android-base/file.h>
     29 #include <android-base/logging.h>
     30 #include <android-base/unique_fd.h>
     31 
     32 using android::base::Timer;
     33 using android::base::unique_fd;
     34 using android::base::WriteFully;
     35 
     36 namespace android {
     37 namespace init {
     38 
     39 static void LoadFirmware(const Uevent& uevent, const std::string& root, int fw_fd, size_t fw_size,
     40                          int loading_fd, int data_fd) {
     41     // Start transfer.
     42     WriteFully(loading_fd, "1", 1);
     43 
     44     // Copy the firmware.
     45     int rc = sendfile(data_fd, fw_fd, nullptr, fw_size);
     46     if (rc == -1) {
     47         PLOG(ERROR) << "firmware: sendfile failed { '" << root << "', '" << uevent.firmware
     48                     << "' }";
     49     }
     50 
     51     // Tell the firmware whether to abort or commit.
     52     const char* response = (rc != -1) ? "0" : "-1";
     53     WriteFully(loading_fd, response, strlen(response));
     54 }
     55 
     56 static bool IsBooting() {
     57     return access("/dev/.booting", F_OK) == 0;
     58 }
     59 
     60 static void ProcessFirmwareEvent(const Uevent& uevent) {
     61     int booting = IsBooting();
     62 
     63     LOG(INFO) << "firmware: loading '" << uevent.firmware << "' for '" << uevent.path << "'";
     64 
     65     std::string root = "/sys" + uevent.path;
     66     std::string loading = root + "/loading";
     67     std::string data = root + "/data";
     68 
     69     unique_fd loading_fd(open(loading.c_str(), O_WRONLY | O_CLOEXEC));
     70     if (loading_fd == -1) {
     71         PLOG(ERROR) << "couldn't open firmware loading fd for " << uevent.firmware;
     72         return;
     73     }
     74 
     75     unique_fd data_fd(open(data.c_str(), O_WRONLY | O_CLOEXEC));
     76     if (data_fd == -1) {
     77         PLOG(ERROR) << "couldn't open firmware data fd for " << uevent.firmware;
     78         return;
     79     }
     80 
     81     static const char* firmware_dirs[] = {"/etc/firmware/", "/odm/firmware/",
     82                                           "/vendor/firmware/", "/firmware/image/"};
     83 
     84 try_loading_again:
     85     for (size_t i = 0; i < arraysize(firmware_dirs); i++) {
     86         std::string file = firmware_dirs[i] + uevent.firmware;
     87         unique_fd fw_fd(open(file.c_str(), O_RDONLY | O_CLOEXEC));
     88         struct stat sb;
     89         if (fw_fd != -1 && fstat(fw_fd, &sb) != -1) {
     90             LoadFirmware(uevent, root, fw_fd, sb.st_size, loading_fd, data_fd);
     91             return;
     92         }
     93     }
     94 
     95     if (booting) {
     96         // If we're not fully booted, we may be missing
     97         // filesystems needed for firmware, wait and retry.
     98         std::this_thread::sleep_for(100ms);
     99         booting = IsBooting();
    100         goto try_loading_again;
    101     }
    102 
    103     LOG(ERROR) << "firmware: could not find firmware for " << uevent.firmware;
    104 
    105     // Write "-1" as our response to the kernel's firmware request, since we have nothing for it.
    106     write(loading_fd, "-1", 2);
    107 }
    108 
    109 void HandleFirmwareEvent(const Uevent& uevent) {
    110     if (uevent.subsystem != "firmware" || uevent.action != "add") return;
    111 
    112     // Loading the firmware in a child means we can do that in parallel...
    113     auto pid = fork();
    114     if (pid == -1) {
    115         PLOG(ERROR) << "could not fork to process firmware event for " << uevent.firmware;
    116     }
    117     if (pid == 0) {
    118         Timer t;
    119         ProcessFirmwareEvent(uevent);
    120         LOG(INFO) << "loading " << uevent.path << " took " << t;
    121         _exit(EXIT_SUCCESS);
    122     }
    123 }
    124 
    125 }  // namespace init
    126 }  // namespace android
    127