diff --git a/microdroid/Android.bp b/microdroid/Android.bp index 8bac103a..21a6c069 100644 --- a/microdroid/Android.bp +++ b/microdroid/Android.bp @@ -104,6 +104,7 @@ android_system_image { "microdroid_plat_sepolicy.cil", "microdroid_plat_mapping_file", + "microdroid_crashdump_initrd", ], }, lib64: { diff --git a/microdroid/kdump/Android.bp b/microdroid/kdump/Android.bp index 1a8c9cce..ffbfcceb 100644 --- a/microdroid/kdump/Android.bp +++ b/microdroid/kdump/Android.bp @@ -8,3 +8,21 @@ cc_binary { srcs: ["kexec.c"], installable: false, } + +cc_binary { + name: "microdroid_crashdump", + stem: "crashdump", + srcs: ["crashdump.c"], + static_executable: true, + installable: false, +} + +android_filesystem { + name: "microdroid_crashdump_initrd", + deps: ["microdroid_crashdump"], + dirs: [ + "dev", + "proc", + ], + type: "cpio", +} diff --git a/microdroid/kdump/crashdump.c b/microdroid/kdump/crashdump.c new file mode 100644 index 00000000..a606d43b --- /dev/null +++ b/microdroid/kdump/crashdump.c @@ -0,0 +1,120 @@ +/* + * Copyright (C) 2022 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +// This program runs as init in the crash kernel. + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define DUMP_SOURCE "/proc/vmcore" +#define DUMP_TARGET "/dev/hvc3" // See virtualizationserice/crosvm.rs +#define BUF_SIZE 4096 + +#define FAIL(format, ...) \ + { \ + fprintf(stderr, format ":%s\n", ##__VA_ARGS__, strerror(errno)); \ + goto fail; \ + } + +// Why declare? __reboot() is the Bionic's system call stub for the reboot syscall. It is +// automatically generated (and is part of API), but Bionic doesn't export this in its headers. +extern int __reboot(int, int, int, void*); + +int main() { + printf("Crashdump started\n"); + + if (mount("proc", "/proc", "proc", 0, NULL) == -1) { + FAIL("Failed to mount /proc"); + } + + if (mount("devtmpfs", "/dev", "devtmpfs", 0, NULL) == -1) { + FAIL("Failed to mount /dev"); + } + + int vmcore = open(DUMP_SOURCE, O_RDONLY); + if (vmcore == -1) { + FAIL("Failed to open %s", DUMP_SOURCE); + } + + int dest = open(DUMP_TARGET, O_WRONLY); + if (dest == -1) { + FAIL("Failed to open %s", DUMP_TARGET); + } + + // We need to turn the line discipline off, otherwise the virtio-console will automatically + // append more data than what we have written because some will be recognized as a control + // sequence. + struct termios term; + if (tcgetattr(dest, &term) != 0) { + FAIL("Failed to get termios for %s", DUMP_TARGET); + } + + cfmakeraw(&term); // Always successful. Returns void. + + if (tcsetattr(dest, TCSAFLUSH, &term) != 0) { + FAIL("Failed to set terminal to the raw mode for %s", DUMP_TARGET); + } + + struct stat statbuf; + if (fstat(vmcore, &statbuf) == -1) { + FAIL("Failed to stat %s", DUMP_SOURCE); + } + printf("Size is %ld bytes\n", statbuf.st_size); + + // sendfile(2) is faster, can't be used because /proc/vmcore doesn't support splice_read + size_t dumped = 0; + char buf[BUF_SIZE]; + int progress = 0; // percentage + + // Disable buffering for better display of the progress + if (setvbuf(stdout, NULL, _IONBF, 0) != 0) { + fprintf(stderr, "Failed to disable buffering for stdout: %s\n", strerror(errno)); + // This isn't a critical error. Continue. + } + + while (dumped < statbuf.st_size) { + ssize_t read_bytes = read(vmcore, buf, BUF_SIZE); + if (read_bytes == -1) { + FAIL("Failed to read from %s", DUMP_SOURCE); + } + ssize_t written_bytes = write(dest, buf, read_bytes); + if (written_bytes == -1) { + FAIL("Failed to write to %s", DUMP_TARGET); + } + dumped += written_bytes; + int new_progress = dumped * 100 / statbuf.st_size; + if (new_progress > progress) { + progress = new_progress; + printf("."); + } + } + printf("done\n"); + + __reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_RESTART2, "kernel panic"); + // Never reach here + +fail: + printf("Crashdump failed\n"); + return 1; +}