diff --git a/src/common/run_command.cpp b/src/common/run_command.cpp index 67608b985f..16fece02f0 100644 --- a/src/common/run_command.cpp +++ b/src/common/run_command.cpp @@ -24,7 +24,7 @@ UniValue RunCommandParseJSON(const std::string& str_command, const std::string& if (str_command.empty()) return UniValue::VNULL; - auto c = sp::Popen(str_command, sp::input{sp::PIPE}, sp::output{sp::PIPE}, sp::error{sp::PIPE}); + auto c = sp::Popen(str_command, sp::input{sp::PIPE}, sp::output{sp::PIPE}, sp::error{sp::PIPE}, sp::close_fds{true}); if (!str_std_in.empty()) { c.send(str_std_in); } diff --git a/src/util/subprocess.h b/src/util/subprocess.h index 3449fa3b1b..91a51466c5 100644 --- a/src/util/subprocess.h +++ b/src/util/subprocess.h @@ -36,6 +36,8 @@ Documentation for C++ subprocessing library. #ifndef BITCOIN_UTIL_SUBPROCESS_H #define BITCOIN_UTIL_SUBPROCESS_H +#include +#include #include #include @@ -520,6 +522,20 @@ namespace util * ------------------------------- */ +/*! + * Option to close all file descriptors + * when the child process is spawned. + * The close fd list does not include + * input/output/error if they are explicitly + * set as part of the Popen arguments. + * + * Default value is false. + */ +struct close_fds { + explicit close_fds(bool c): close_all(c) {} + bool close_all = false; +}; + /*! * Base class for all arguments involving string value. */ @@ -717,6 +733,7 @@ struct ArgumentDeducer void set_option(input&& inp); void set_option(output&& out); void set_option(error&& err); + void set_option(close_fds&& cfds); private: Popen* popen_ = nullptr; @@ -1004,6 +1021,8 @@ private: std::future cleanup_future_; #endif + bool close_fds_ = false; + std::string exe_name_; // Command in string format @@ -1233,6 +1252,10 @@ namespace detail { if (err.rd_ch_ != -1) popen_->stream_.err_read_ = err.rd_ch_; } + inline void ArgumentDeducer::set_option(close_fds&& cfds) { + popen_->close_fds_ = cfds.close_all; + } + inline void Child::execute_child() { #ifndef __USING_WINDOWS__ @@ -1279,6 +1302,25 @@ namespace detail { if (stream.err_write_ != -1 && stream.err_write_ > 2) close(stream.err_write_); + // Close all the inherited fd's except the error write pipe + if (parent_->close_fds_) { + try { + std::vector fds_to_close; + for (const auto& it : fs::directory_iterator("/proc/self/fd")) { + int64_t fd; + if (!ParseInt64(it.path().filename().native(), &fd)) continue; + if (fd <= 2) continue; // leave std{in,out,err} alone + if (fd == err_wr_pipe_) continue; + fds_to_close.push_back(fd); + } + for (const int fd : fds_to_close) { + close(fd); + } + } catch (...) { + // TODO: maybe log this - but we're in a child process, so maybe non-trivial! + } + } + // Replace the current image with the executable sys_ret = execvp(parent_->exe_name_.c_str(), parent_->cargv_.data());