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init: mount_handler: detect main block device more reliably 

Current code is not portable beyond SCSI devices (e.g., UFS).
For example, eMMC and NVMe devices fail due to their extra postfix.

Change its logic to rewind each character until "queue" directory appears.

Test: Confirm md0p1, sda20, nvme0n1p3, mmcblk0p3 are all handled well.
Change-Id: I585ccf2d4a72f6ef8ecb203acdd72a1e32d3e749
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
This commit is contained in:
Juhyung Park 2022-02-15 19:18:46 +09:00 committed by Jaegeuk Kim
parent 852111eea4
commit 491004bbfb
1 changed files with 24 additions and 10 deletions
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34
init/mount_handler.cpp
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@ -25,6 +25,7 @@
#include <unistd.h>
#include <algorithm>
#include <filesystem>
#include <string>
#include <utility>
#include <vector>
@ -32,6 +33,7 @@
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <fs_mgr.h>
#include <fstab/fstab.h>
@ -39,6 +41,9 @@
#include "epoll.h"
using android::base::Basename;
using android::base::StringPrintf;
namespace android {
namespace init {
@ -67,21 +72,30 @@ MountHandlerEntry ParseMount(const std::string& line) {
return MountHandlerEntry(fields[0], fields[1], fields[2]);
}
// return dm-4 or dm-8 for dm-4, sda for sda25, or mmcblk0 for mmcblk0p24
std::string GetRootDisk(std::string blockdev) {
if (blockdev.find('/') != std::string::npos) return {};
std::error_code ec;
for (const auto& entry : std::filesystem::directory_iterator("/sys/block", ec)) {
const std::string path = entry.path().string();
if (std::filesystem::exists(StringPrintf("%s/%s", path.c_str(), blockdev.c_str()))) {
return Basename(path);
}
}
if (android::base::StartsWith(blockdev, "dm-")) return blockdev;
return {};
}
void SetMountProperty(const MountHandlerEntry& entry, bool add) {
static constexpr char devblock[] = "/dev/block/";
if (!android::base::StartsWith(entry.blk_device, devblock)) return;
auto target = entry.blk_device.substr(strlen(devblock));
std::string value;
if (add) {
value = entry.blk_device.substr(strlen(devblock));
if (android::base::StartsWith(value, "sd")) {
// All sd partitions inherit their queue characteristics
// from the whole device reference. Strip partition number.
auto it = std::find_if(value.begin(), value.end(), [](char c) { return isdigit(c); });
if (it != value.end()) value.erase(it, value.end());
}
auto queue = "/sys/block/" + value + "/queue";
value = GetRootDisk(target);
struct stat sb;
if (stat(queue.c_str(), &sb) || !S_ISDIR(sb.st_mode)) value = "";
if (stat(entry.mount_point.c_str(), &sb) || !S_ISDIR(sb.st_mode)) value = "";
// Clear the noise associated with loopback and APEX.
if (android::base::StartsWith(value, "loop")) value = "";
@ -98,7 +112,7 @@ void SetMountProperty(const MountHandlerEntry& entry, bool add) {
if (value.empty() && android::base::GetProperty(blk_mount_prop, "").empty()) return;
android::base::SetProperty(blk_mount_prop, value);
if (!value.empty()) {
android::base::SetProperty(dev_mount_prop, entry.blk_device.substr(strlen(devblock)));
android::base::SetProperty(dev_mount_prop, target);
} else {
android::base::SetProperty(dev_mount_prop, "");
}