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Diffstat (limited to 'utils/process/child.cpp')
| -rw-r--r-- | utils/process/child.cpp | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/utils/process/child.cpp b/utils/process/child.cpp new file mode 100644 index 000000000000..fef09ccaad3b --- /dev/null +++ b/utils/process/child.cpp @@ -0,0 +1,385 @@ +// Copyright 2010 The Kyua Authors. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in the +// documentation and/or other materials provided with the distribution. +// * Neither the name of Google Inc. nor the names of its contributors +// may be used to endorse or promote products derived from this software +// without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "utils/process/child.ipp" + +extern "C" { +#include <sys/stat.h> +#include <sys/wait.h> + +#include <fcntl.h> +#include <signal.h> +#include <unistd.h> +} + +#include <cerrno> +#include <iostream> +#include <memory> + +#include "utils/defs.hpp" +#include "utils/format/macros.hpp" +#include "utils/fs/path.hpp" +#include "utils/logging/macros.hpp" +#include "utils/noncopyable.hpp" +#include "utils/process/exceptions.hpp" +#include "utils/process/fdstream.hpp" +#include "utils/process/operations.hpp" +#include "utils/process/system.hpp" +#include "utils/process/status.hpp" +#include "utils/sanity.hpp" +#include "utils/signals/interrupts.hpp" + + +namespace utils { +namespace process { + + +/// Private implementation fields for child objects. +struct child::impl : utils::noncopyable { + /// The process identifier. + pid_t _pid; + + /// The input stream for the process' stdout and stderr. May be NULL. + std::auto_ptr< process::ifdstream > _output; + + /// Initializes private implementation data. + /// + /// \param pid The process identifier. + /// \param output The input stream. Grabs ownership of the pointer. + impl(const pid_t pid, process::ifdstream* output) : + _pid(pid), _output(output) {} +}; + + +} // namespace process +} // namespace utils + + +namespace fs = utils::fs; +namespace process = utils::process; +namespace signals = utils::signals; + + +namespace { + + +/// Exception-based version of dup(2). +/// +/// \param old_fd The file descriptor to duplicate. +/// \param new_fd The file descriptor to use as the duplicate. This is +/// closed if it was open before the copy happens. +/// +/// \throw process::system_error If the call to dup2(2) fails. +static void +safe_dup(const int old_fd, const int new_fd) +{ + if (process::detail::syscall_dup2(old_fd, new_fd) == -1) { + const int original_errno = errno; + throw process::system_error(F("dup2(%s, %s) failed") % old_fd % new_fd, + original_errno); + } +} + + +/// Exception-based version of open(2) to open (or create) a file for append. +/// +/// \param filename The file to open in append mode. +/// +/// \return The file descriptor for the opened or created file. +/// +/// \throw process::system_error If the call to open(2) fails. +static int +open_for_append(const fs::path& filename) +{ + const int fd = process::detail::syscall_open( + filename.c_str(), O_CREAT | O_WRONLY | O_APPEND, + S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH); + if (fd == -1) { + const int original_errno = errno; + throw process::system_error(F("Failed to create %s because open(2) " + "failed") % filename, original_errno); + } + return fd; +} + + +/// Logs the execution of another program. +/// +/// \param program The binary to execute. +/// \param args The arguments to pass to the binary, without the program name. +static void +log_exec(const fs::path& program, const process::args_vector& args) +{ + std::string plain_command = program.str(); + for (process::args_vector::const_iterator iter = args.begin(); + iter != args.end(); ++iter) + plain_command += F(" %s") % *iter; + LD(F("Executing %s") % plain_command); +} + + +} // anonymous namespace + + +/// Prints out a fatal error and aborts. +void +utils::process::detail::report_error_and_abort(void) +{ + std::cerr << "Caught unknown exception\n"; + std::abort(); +} + + +/// Prints out a fatal error and aborts. +/// +/// \param error The error to display. +void +utils::process::detail::report_error_and_abort(const std::runtime_error& error) +{ + std::cerr << "Caught runtime_error: " << error.what() << '\n'; + std::abort(); +} + + +/// Creates a new child. +/// +/// \param implptr A dynamically-allocated impl object with the contents of the +/// new child. +process::child::child(impl *implptr) : + _pimpl(implptr) +{ +} + + +/// Destructor for child. +process::child::~child(void) +{ +} + + +/// Helper function for fork(). +/// +/// Please note: if you update this function to change the return type or to +/// raise different errors, do not forget to update fork() accordingly. +/// +/// \return In the case of the parent, a new child object returned as a +/// dynamically-allocated object because children classes are unique and thus +/// noncopyable. In the case of the child, a NULL pointer. +/// +/// \throw process::system_error If the calls to pipe(2) or fork(2) fail. +std::auto_ptr< process::child > +process::child::fork_capture_aux(void) +{ + std::cout.flush(); + std::cerr.flush(); + + int fds[2]; + if (detail::syscall_pipe(fds) == -1) + throw process::system_error("pipe(2) failed", errno); + + std::auto_ptr< signals::interrupts_inhibiter > inhibiter( + new signals::interrupts_inhibiter); + pid_t pid = detail::syscall_fork(); + if (pid == -1) { + inhibiter.reset(NULL); // Unblock signals. + ::close(fds[0]); + ::close(fds[1]); + throw process::system_error("fork(2) failed", errno); + } else if (pid == 0) { + inhibiter.reset(NULL); // Unblock signals. + ::setsid(); + + try { + ::close(fds[0]); + safe_dup(fds[1], STDOUT_FILENO); + safe_dup(fds[1], STDERR_FILENO); + ::close(fds[1]); + } catch (const system_error& e) { + std::cerr << F("Failed to set up subprocess: %s\n") % e.what(); + std::abort(); + } + return std::auto_ptr< process::child >(NULL); + } else { + ::close(fds[1]); + LD(F("Spawned process %s: stdout and stderr inherited") % pid); + signals::add_pid_to_kill(pid); + inhibiter.reset(NULL); // Unblock signals. + return std::auto_ptr< process::child >( + new process::child(new impl(pid, new process::ifdstream(fds[0])))); + } +} + + +/// Helper function for fork(). +/// +/// Please note: if you update this function to change the return type or to +/// raise different errors, do not forget to update fork() accordingly. +/// +/// \param stdout_file The name of the file in which to store the stdout. +/// If this has the magic value /dev/stdout, then the parent's stdout is +/// reused without applying any redirection. +/// \param stderr_file The name of the file in which to store the stderr. +/// If this has the magic value /dev/stderr, then the parent's stderr is +/// reused without applying any redirection. +/// +/// \return In the case of the parent, a new child object returned as a +/// dynamically-allocated object because children classes are unique and thus +/// noncopyable. In the case of the child, a NULL pointer. +/// +/// \throw process::system_error If the call to fork(2) fails. +std::auto_ptr< process::child > +process::child::fork_files_aux(const fs::path& stdout_file, + const fs::path& stderr_file) +{ + std::cout.flush(); + std::cerr.flush(); + + std::auto_ptr< signals::interrupts_inhibiter > inhibiter( + new signals::interrupts_inhibiter); + pid_t pid = detail::syscall_fork(); + if (pid == -1) { + inhibiter.reset(NULL); // Unblock signals. + throw process::system_error("fork(2) failed", errno); + } else if (pid == 0) { + inhibiter.reset(NULL); // Unblock signals. + ::setsid(); + + try { + if (stdout_file != fs::path("/dev/stdout")) { + const int stdout_fd = open_for_append(stdout_file); + safe_dup(stdout_fd, STDOUT_FILENO); + ::close(stdout_fd); + } + if (stderr_file != fs::path("/dev/stderr")) { + const int stderr_fd = open_for_append(stderr_file); + safe_dup(stderr_fd, STDERR_FILENO); + ::close(stderr_fd); + } + } catch (const system_error& e) { + std::cerr << F("Failed to set up subprocess: %s\n") % e.what(); + std::abort(); + } + return std::auto_ptr< process::child >(NULL); + } else { + LD(F("Spawned process %s: stdout=%s, stderr=%s") % pid % stdout_file % + stderr_file); + signals::add_pid_to_kill(pid); + inhibiter.reset(NULL); // Unblock signals. + return std::auto_ptr< process::child >( + new process::child(new impl(pid, NULL))); + } +} + + +/// Spawns a new binary and multiplexes and captures its stdout and stderr. +/// +/// If the subprocess cannot be completely set up for any reason, it attempts to +/// dump an error message to its stderr channel and it then calls std::abort(). +/// +/// \param program The binary to execute. +/// \param args The arguments to pass to the binary, without the program name. +/// +/// \return A new child object, returned as a dynamically-allocated object +/// because children classes are unique and thus noncopyable. +/// +/// \throw process::system_error If the process cannot be spawned due to a +/// system call error. +std::auto_ptr< process::child > +process::child::spawn_capture(const fs::path& program, const args_vector& args) +{ + std::auto_ptr< child > child = fork_capture_aux(); + if (child.get() == NULL) + exec(program, args); + log_exec(program, args); + return child; +} + + +/// Spawns a new binary and redirects its stdout and stderr to files. +/// +/// If the subprocess cannot be completely set up for any reason, it attempts to +/// dump an error message to its stderr channel and it then calls std::abort(). +/// +/// \param program The binary to execute. +/// \param args The arguments to pass to the binary, without the program name. +/// \param stdout_file The name of the file in which to store the stdout. +/// \param stderr_file The name of the file in which to store the stderr. +/// +/// \return A new child object, returned as a dynamically-allocated object +/// because children classes are unique and thus noncopyable. +/// +/// \throw process::system_error If the process cannot be spawned due to a +/// system call error. +std::auto_ptr< process::child > +process::child::spawn_files(const fs::path& program, + const args_vector& args, + const fs::path& stdout_file, + const fs::path& stderr_file) +{ + std::auto_ptr< child > child = fork_files_aux(stdout_file, stderr_file); + if (child.get() == NULL) + exec(program, args); + log_exec(program, args); + return child; +} + + +/// Returns the process identifier of this child. +/// +/// \return A process identifier. +int +process::child::pid(void) const +{ + return _pimpl->_pid; +} + + +/// Gets the input stream corresponding to the stdout and stderr of the child. +/// +/// \pre The child must have been started by fork_capture(). +/// +/// \return A reference to the input stream connected to the output of the test +/// case. +std::istream& +process::child::output(void) +{ + PRE(_pimpl->_output.get() != NULL); + return *_pimpl->_output; +} + + +/// Blocks to wait for completion. +/// +/// \return The termination status of the child process. +/// +/// \throw process::system_error If the call to waitpid(2) fails. +process::status +process::child::wait(void) +{ + return process::wait(_pimpl->_pid); +} |