Resolve "log_fd interacting with vfork/execve and syscall intercept in java" (cc74fc83) · Commits · hpc / gekkofs

CHANGELOG.md

+2 −0

Original line number	Diff line number	Diff line
		@@ -34,6 +34,8 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
		- Directories shows . and .. to support scandir ([!248](https://storage.bsc.es/gitlab/hpc/gekkofs/-/merge_requests/248))
		- updated fmt, spdlog and pytest versions ([!249](https://storage.bsc.es/gitlab/hpc/gekkofs/-/merge_requests/249))
		- Updated Docker images for 0.9.5 ([!238](https://storage.bsc.es/gitlab/hpc/gekkofs/-/merge_requests/238))
		- Logging uses a higher FD limit ([!259](https://storage.bsc.es/gitlab/hpc/gekkofs/-/merge_requests/259))
		- Avoid throwing runtime error if the fd is invalid (may happen on destruction)

		### Fixed
		- Dup3 is supported if O_CLOEXEC is not used (i.e. hexdump) ([!228](https://storage.bsc.es/gitlab/hpc/gekkofs/-/merge_requests/228))

include/client/logging.hpp

+4 −9

Original line number	Diff line number	Diff line
		@@ -168,22 +168,17 @@ log_buffer(std::FILE* fp, Buffer&& buffer) {
		template <typename Buffer>
		static inline void
		log_buffer(int fd, Buffer&& buffer) {

		if(fd < 0) {
		throw std::runtime_error("Invalid file descriptor");
		}

		if(fd > 0) {
		::syscall_no_intercept(SYS_write, fd, buffer.data(), buffer.size());
		}
		}

		static inline void
		log_buffer(int fd, const void* buffer, std::size_t length) {
		if(fd < 0) {
		throw std::runtime_error("Invalid file descriptor");
		}

		if(fd > 0) {
		::syscall_no_intercept(SYS_write, fd, buffer, length);
		}
		}

		/**
		* @brief convert a time_t to a tm

include/client/syscalls/args.hpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -517,7 +517,7 @@ format_clone3_args_arg_to(FmtBuffer& buffer, const printable_arg& parg) {
		format_flag_set(buffer, ca->flags, flag_names);

		fmt::format_to(std::back_inserter(buffer), "\|", "signal");
		format_signum_arg_to(buffer, {"", ca->exit_signal});
		format_signum_arg_to(buffer, {"", static_cast<int>(ca->exit_signal)});

		fmt::format_to(std::back_inserter(buffer), ",{}={}", "pidfd", (void*)ca->pidfd);
		fmt::format_to(std::back_inserter(buffer), ",{}={}", "child_tid", (void*)ca->child_tid);

src/client/gkfs_libc.cpp

+2 −1

Original line number	Diff line number	Diff line
		@@ -110,6 +110,7 @@ static ResultEntry* results = nullptr;
		#ifdef GKFS_TRACE
		#define DEBUG_INFO(...) \
		do { \
		if(CTX->interception_enabled()) \
		LOG(DEBUG, __VA_ARGS__); \
		} while(0)
		#else

src/client/logging.cpp

+60 −1

Original line number	Diff line number	Diff line
		@@ -43,6 +43,7 @@
		#include <regex>
		#include <filesystem>
		#include <ctime>
		#include <sys/resource.h>

		#ifdef GKFS_ENABLE_LOGGING

		@@ -336,9 +337,67 @@ logger::logger(const std::string& opts, const std::string& path,
		path);
		return;
		}
		// Pseudo protect fd to a higher fd with dup2

		struct rlimit rlim;
		if(getrlimit(RLIMIT_NOFILE, &rlim) == -1) {
		perror("GekkoFS Log: getrlimit(RLIMIT_NOFILE) failed");
		log_fd_ = fd;
		fprintf(stderr,
		"GekkoFS Log: Using original FD %d due to getrlimit error.\n",
		log_fd_);
		return; // Or error
		}

		int target_fd = -1;
		if(rlim.rlim_cur >
		25000) { // It shouldn't be too high, if not we have memory issues
		target_fd = 24000;
		} else if(rlim.rlim_cur > 3) { // If limit is small, pick the highest
		// possible that's not 0,1,2
		target_fd = rlim.rlim_cur - 1;
		} else {
		fprintf(stderr,
		"GekkoFS Log: RLIMIT_NOFILE is too small (%llu) to pick a high FD. Using original FD %d.\n",
		(unsigned long long) rlim.rlim_cur, fd);
		log_fd_ = fd;

		return;
		}

		// Check if target_fd is already the original_fd
		if(target_fd == fd) {
		log_fd_ = fd;
		} else {
		// Duplicate original_fd to target_fd.
		// dup2 will close target_fd if it's already open.
		if(dup2(fd, target_fd) == -1) {
		fprintf(stderr, "GekkoFS Log: dup2 error for : %d.\n",
		target_fd);
		perror("GekkoFS Log: dup2 failed");
		// Failed to move to high FD, try to use original_fd or error
		// out
		close(fd); // Close the one we opened
		return;
		}
		// Now that original_fd is duplicated to target_fd, we can close
		// original_fd. All writes should go to target_fd.
		if(close(fd) == -1) {
		perror("GekkoFS Log: Failed to close original_fd after dup2");
		}
		log_fd_ = target_fd;
		}

		flags = fcntl(log_fd_, F_GETFD);
		if(flags == -1) {
		perror("GekkoFS Log: fcntl(F_GETFD) failed on new log FD");
		} else {
		if(fcntl(log_fd_, F_SETFD, flags \| FD_CLOEXEC) == -1) {
		perror("GekkoFS Log: fcntl failed on new log FD");
		}
		}
		}


		#ifdef GKFS_ENABLE_LOGGING
		const auto log_hermes_message =