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Merge pull request #565 from bytedance/feat-overlay
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feat overlay and devicemapper storage driver
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@yoloyyh
yoloyyh committed Dec 27, 2023
2 parents 136657e + 95ab88e commit 7ab69b6
Showing 1 changed file with 144 additions and 29 deletions.
173 changes: 144 additions & 29 deletions rasp/NSMount/main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2,45 +2,82 @@
#include <zero/cmdline.h>
#include <sys/mount.h>

int main(int argc, char *argv[]) {
INIT_CONSOLE_LOG(zero::INFO_LEVEL);
enum FSType {
Overlay,
devicemapper
};

std::string find_rootfs_overlay(const std::string& workdir) {
std::filesystem::path mountinfo_path = std::filesystem::path("/proc/mounts");
std::ifstream stream_path(mountinfo_path);

if (!stream_path.is_open()) {
LOG_ERROR("failed to open %s information[%d]", mountinfo_path.u8string().c_str(), stream_path.rdstate());
return "";
}

zero::Cmdline cmdline;
std::string line_root;
std::string rootdir;

cmdline.add<int>("pid", "target process id");
cmdline.add<std::filesystem::path>("src", "source path");
cmdline.add<std::filesystem::path>("dst", "destination path");
while (std::getline(stream_path, line_root)) {
std::vector<std::string> tokens = zero::strings::split(line_root, " ", 5);

cmdline.parse(argc, argv);
if (tokens.size() != 6)
continue;

auto pid = cmdline.get<int>("pid");
auto src = cmdline.get<std::filesystem::path>("src");
auto dst = cmdline.get<std::filesystem::path>("dst");
if (tokens[3].find(workdir) != std::string::npos) {
rootdir = tokens[1];
break;
}
}
return rootdir;
}

std::error_code ec;
std::string find_rootfs_devicemapper(const std::string& workdir) {
std::filesystem::path mountinfo_path = std::filesystem::path("/proc/mounts");
std::ifstream stream_path(mountinfo_path);

if (!std::filesystem::exists(src, ec)) {
LOG_ERROR("source path %s not exists[%s]", src.u8string().c_str(), ec.message().c_str());
return -1;
if (!stream_path.is_open()) {
LOG_ERROR("failed to open %s information[%d]", mountinfo_path.u8string().c_str(), stream_path.rdstate());
return "";
}

std::string line_root;
std::string rootdir;

while (std::getline(stream_path, line_root)) {
std::vector<std::string> tokens = zero::strings::split(line_root, " ", 5);

if (tokens.size() != 6)
continue;

if (tokens[0] == workdir) {
rootdir = tokens[1];
rootdir += "/rootfs";
break;
}
}
return rootdir;
}

std::string find_workdir_overlayfs(int pid) {
std::filesystem::path path = std::filesystem::path("/proc") / std::to_string(pid) / "mounts";
std::ifstream stream(path);

if (!stream.is_open()) {
LOG_ERROR("failed to open %s information[%d]", path.u8string().c_str(), stream.rdstate());
return -1;
return "";
}

std::string line;
std::optional<std::filesystem::path> workdir;
std::string workdir;

while (std::getline(stream, line)) {
std::vector<std::string> tokens = zero::strings::split(line, " ", 5);

if (tokens.size() != 6)
continue;

// overlay fs, from linux kernel 3.18
if (tokens[0] == "overlay" && tokens[1] == "/") {
tokens = zero::strings::split(tokens[3], ",");

Expand All @@ -55,33 +92,111 @@ int main(int argc, char *argv[]) {
break;
}
}
return workdir;
}

std::string find_workdir_devicemapper(int pid) {
std::filesystem::path path = std::filesystem::path("/proc") / std::to_string(pid) / "mounts";
std::ifstream stream(path);

if (!workdir) {
LOG_ERROR("failed to find workdir of overlay filesystem");
if (!stream.is_open()) {
LOG_ERROR("failed to open %s information[%d]", path.u8string().c_str(), stream.rdstate());
return "";
}

std::string line;
std::string workdir;

while (std::getline(stream, line)) {
std::vector<std::string> tokens = zero::strings::split(line, " ", 5);

if (tokens.size() != 6)
continue;
// devicemapper, form linux kernel 2.6.9
if (tokens[1] == "/") {
workdir = tokens[0];
break;
}
}
return workdir;
}

int main(int argc, char *argv[]) {
INIT_CONSOLE_LOG(zero::INFO_LEVEL);

zero::Cmdline cmdline;

FSType fs_type;

cmdline.add<int>("pid", "target process id");
cmdline.add<std::filesystem::path>("src", "source path");
cmdline.add<std::filesystem::path>("dst", "destination path");

cmdline.parse(argc, argv);

auto pid = cmdline.get<int>("pid");
auto src = cmdline.get<std::filesystem::path>("src");
auto dst = cmdline.get<std::filesystem::path>("dst");

std::error_code ec;

if (!std::filesystem::exists(src, ec)) {
LOG_ERROR("source path %s not exists[%s]", src.u8string().c_str(), ec.message().c_str());
return -1;
}

LOG_INFO("workdir: %s", workdir->u8string().c_str());
std::string workdir = find_workdir_overlayfs(pid);

std::filesystem::path merged = workdir->parent_path() / "merged";
if (workdir.empty()) {
workdir = find_workdir_devicemapper(pid);
if (workdir.empty()) {
LOG_ERROR("failed to find workdir of devicemapper and overlay filesystem");
return -1;
} else {
fs_type = FSType::devicemapper;
}
} else {
fs_type = FSType::Overlay;
}

LOG_INFO("workdir: %s", workdir.c_str());

std::string root_path;

if (fs_type == FSType::Overlay) {
root_path = find_rootfs_overlay(workdir);
} else {
root_path = find_rootfs_devicemapper(workdir);
}

if (root_path.empty()) {
LOG_ERROR("failed to find rootfs of overlay filesystem, workdir : %s", workdir.c_str());
return -1;
}

LOG_INFO("rootdir: %s", root_path.c_str());

std::filesystem::path merged = root_path;

if (!std::filesystem::exists(merged, ec)) {
LOG_ERROR("directory %s not exists[%s]", merged.u8string().c_str(), ec.message().c_str());
LOG_WARNING("directory %s not exists: %s", merged.u8string().c_str(), ec.message().c_str());
return -1;
}

dst = merged / dst.relative_path();

if (std::filesystem::exists(dst, ec)) {
LOG_WARNING("directory %s already exists", dst.u8string().c_str());

// when container restart, the directory is exist but empty
if (std::filesystem::exists(dst, ec) && !std::filesystem::is_empty(dst)) {
LOG_WARNING("directory %s already exists and not empty", dst.u8string().c_str());
return 0;
}

LOG_INFO("bind %s -> %s", src.u8string().c_str(), dst.u8string().c_str());

if (!std::filesystem::create_directories(dst, ec)) {
LOG_ERROR("create directory %s failed[%s]", dst.u8string().c_str(), ec.message().c_str());
return -1;
if (!std::filesystem::exists(dst)) {
if (!std::filesystem::create_directories(dst, ec)) {
LOG_ERROR("create directory %s failed[%s]", dst.u8string().c_str(), ec.message().c_str());
return -1;
}
}

if (mount(src.u8string().c_str(), dst.u8string().c_str(), "ext4", MS_BIND, nullptr) < 0) {
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