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authorKaren Arutyunov <karen@codesynthesis.com>2017-05-01 16:08:43 +0300
committerKaren Arutyunov <karen@codesynthesis.com>2017-05-01 16:59:24 +0300
commit61377c582e0f2675baa5f5e6e30a35d1a4164b33 (patch)
tree11cdca992834d7f7f197f72856712fbcb3020e3d /butl/process.cxx
parent442c1a6790e52baa0c081f310d4d9e9b6f1ff638 (diff)
Add hxx extension for headers and lib prefix for library dir
Diffstat (limited to 'butl/process.cxx')
-rw-r--r--butl/process.cxx1440
1 files changed, 0 insertions, 1440 deletions
diff --git a/butl/process.cxx b/butl/process.cxx
deleted file mode 100644
index 940560c..0000000
--- a/butl/process.cxx
+++ /dev/null
@@ -1,1440 +0,0 @@
-// file : butl/process.cxx -*- C++ -*-
-// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
-// license : MIT; see accompanying LICENSE file
-
-#include <butl/process>
-
-#ifndef _WIN32
-# include <unistd.h> // execvp, fork, dup2, pipe, chdir, *_FILENO, getpid
-# include <sys/wait.h> // waitpid
-# include <sys/types.h> // _stat
-# include <sys/stat.h> // _stat(), S_IS*
-#else
-# include <butl/win32-utility>
-
-# include <psapi.h> // EnumProcessModules(), etc
-
-# include <io.h> // _get_osfhandle(), _close()
-# include <stdlib.h> // _MAX_PATH
-# include <sys/types.h> // stat
-# include <sys/stat.h> // stat(), S_IS*
-
-# ifdef _MSC_VER // Unlikely to be fixed in newer versions.
-# define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
-
-# define STDIN_FILENO 0
-# define STDOUT_FILENO 1
-# define STDERR_FILENO 2
-# endif // _MSC_VER
-
-# include <cstdlib> // getenv(), __argv[]
-
-# include <butl/small-vector>
-#endif
-
-#include <errno.h>
-
-#include <ios> // ios_base::failure
-#include <cassert>
-#include <cstddef> // size_t
-#include <cstring> // strlen(), strchr()
-#include <utility> // move()
-#include <ostream>
-
-#include <butl/utility> // casecmp()
-#include <butl/fdstream> // fdnull()
-#include <butl/process-details>
-
-#include <iostream>
-
-using namespace std;
-
-#ifdef _WIN32
-using namespace butl::win32;
-#endif
-
-namespace butl
-{
- shared_mutex process_spawn_mutex;
-
- // process
- //
- static process_path
- path_search (const char*, const dir_path&);
-
- process_path process::
- path_search (const char* f, bool init, const dir_path& fb)
- {
- process_path r (try_path_search (f, init, fb));
-
- if (r.empty ())
- throw process_error (ENOENT);
-
- return r;
- }
-
- process_path process::
- try_path_search (const char* f, bool init, const dir_path& fb)
- {
- process_path r (butl::path_search (f, fb));
-
- if (!init && !r.empty ())
- {
- path& rp (r.recall);
- r.initial = (rp.empty () ? (rp = path (f)) : rp).string ().c_str ();
- }
-
- return r;
- }
-
- void process::
- print (ostream& o, const char* const args[], size_t n)
- {
- size_t m (0);
- const char* const* p (args);
- do
- {
- if (m != 0)
- o << " |"; // Trailing space will be added inside the loop.
-
- for (m++; *p != nullptr; p++, m++)
- {
- if (p != args)
- o << ' ';
-
- // Quote if empty or contains spaces.
- //
- bool q (**p == '\0' || strchr (*p, ' ') != nullptr);
-
- if (q)
- o << '"';
-
- o << *p;
-
- if (q)
- o << '"';
- }
-
- if (m < n) // Can we examine the next element?
- {
- p++;
- m++;
- }
-
- } while (*p != nullptr);
- }
-
- process::
- process (const char* cwd,
- const process_path& pp, const char* args[],
- process& in, int out, int err)
- : process (cwd, pp, args, in.in_ofd.get (), out, err)
- {
- assert (in.in_ofd.get () != -1); // Should be a pipe.
- in.in_ofd.reset (); // Close it on our side.
- }
-
-#ifndef _WIN32
-
- static process_path
- path_search (const char* f, const dir_path& fb)
- {
- // Note that there is a similar version for Win32.
-
- typedef path::traits traits;
-
- size_t fn (strlen (f));
-
- process_path r (f, path (), path ()); // Make sure it is not empty.
- path& rp (r.recall);
- path& ep (r.effect);
-
- // Check that the file exists and has at least one executable bit set.
- // This way we get a bit closer to the "continue search on EACCES"
- // semantics (see below).
- //
- auto exists = [] (const char* f) -> bool
- {
- struct stat si;
- return (stat (f, &si) == 0 &&
- S_ISREG (si.st_mode) &&
- (si.st_mode & (S_IEXEC | S_IXGRP | S_IXOTH)) != 0);
- };
-
- auto search = [&ep, f, fn, &exists] (const char* d,
- size_t dn,
- bool norm = false) -> bool
- {
- string s (move (ep).string ()); // Reuse buffer.
-
- if (dn != 0)
- {
- s.assign (d, dn);
-
- if (!traits::is_separator (s.back ()))
- s += traits::directory_separator;
- }
-
- s.append (f, fn);
- ep = path (move (s)); // Move back into result.
-
- if (norm)
- ep.normalize ();
-
- return exists (ep.string ().c_str ());
- };
-
- // If there is a directory component in the file, then the PATH search
- // does not apply. If the path is relative, then prepend CWD. In both
- // cases make sure the file actually exists.
- //
- if (traits::find_separator (f, fn) != nullptr)
- {
- if (traits::absolute (f, fn))
- {
- if (exists (f))
- return r;
- }
- else
- {
- const string& d (traits::current_directory ());
-
- if (search (d.c_str (), d.size (), true))
- return r;
- }
-
- return process_path ();
- }
-
- // The search order is documented in exec(3). Some of the differences
- // compared to exec*p() functions:
- //
- // 1. If there no PATH, we don't default to current directory/_CS_PATH.
- // 2. We do not continue searching on EACCES from execve().
- // 3. We do not execute via default shell on ENOEXEC from execve().
- //
- for (const char* b (getenv ("PATH")), *e;
- b != nullptr;
- b = (e != nullptr ? e + 1 : e))
- {
- e = strchr (b, traits::path_separator);
-
- // Empty path (i.e., a double colon or a colon at the beginning or end
- // of PATH) means search in the current dirrectory. Silently skip
- // invalid paths.
- //
- try
- {
- if (search (b, e != nullptr ? e - b : strlen (b)))
- return r;
- }
- catch (const invalid_path&)
- {
- }
- }
-
- // If we were given a fallback, try that.
- //
- if (!fb.empty ())
- {
- if (search (fb.string ().c_str (), fb.string ().size ()))
- {
- // In this case we have to set the recall path. And we know from
- // search() implementation that it will be the same as effective.
- // Which means we can just move effective to recall.
- //
- rp.swap (ep);
-
- return r;
- }
- }
-
- // Did not find anything.
- //
- return process_path ();
- }
-
- process::
- process (const char* cwd,
- const process_path& pp, const char* args[],
- int in, int out, int err)
- {
- fdpipe out_fd;
- fdpipe in_ofd;
- fdpipe in_efd;
-
- auto fail = [] (bool child)
- {
- if (child)
- throw process_child_error (errno);
- else
- throw process_error (errno);
- };
-
- auto open_pipe = [] () -> fdpipe
- {
- try
- {
- return fdopen_pipe ();
- }
- catch (const ios_base::failure&)
- {
- // Translate to process_error.
- //
- // For old versions of g++ (as of 4.9) ios_base::failure is not derived
- // from system_error and so we cannot recover the errno value. On the
- // other hand the only possible values are EMFILE and ENFILE. Lets use
- // EMFILE as the more probable. This is a temporary code after all.
- //
- throw process_error (EMFILE);
- }
- };
-
- auto open_null = [] () -> auto_fd
- {
- try
- {
- return fdnull ();
- }
- catch (const ios_base::failure& e)
- {
- // Translate to process_error.
- //
- // For old versions of g++ (as of 4.9) ios_base::failure is not derived
- // from system_error and so we cannot recover the errno value. Lets use
- // EIO in this case. This is a temporary code after all.
- //
- const system_error* se (dynamic_cast<const system_error*> (&e));
-
- throw process_error (se != nullptr
- ? se->code ().value ()
- : EIO);
- }
- };
-
- // If we are asked to open null (-2) then open "half-pipe".
- //
- if (in == -1)
- out_fd = open_pipe ();
- else if (in == -2)
- out_fd.in = open_null ();
-
- if (out == -1)
- in_ofd = open_pipe ();
- else if (out == -2)
- in_ofd.out = open_null ();
-
- if (err == -1)
- in_efd = open_pipe ();
- else if (err == -2)
- in_efd.out = open_null ();
-
- {
- ulock l (process_spawn_mutex); // Will not be released in child.
- handle = fork ();
-
- if (handle == -1)
- fail (false);
-
- if (handle == 0)
- {
- // Child.
- //
- // Duplicate the user-supplied (fd > -1) or the created pipe descriptor
- // to the standard stream descriptor (read end for STDIN_FILENO, write
- // end otherwise). Close the pipe afterwards.
- //
- auto duplicate = [&fail] (int sd, int fd, fdpipe& pd)
- {
- if (fd == -1 || fd == -2)
- fd = (sd == STDIN_FILENO ? pd.in : pd.out).get ();
-
- assert (fd > -1);
- if (dup2 (fd, sd) == -1)
- fail (true);
-
- pd.in.reset (); // Silently close.
- pd.out.reset (); // Silently close.
- };
-
- if (in != STDIN_FILENO)
- duplicate (STDIN_FILENO, in, out_fd);
-
- // If stdout is redirected to stderr (out == 2) we need to duplicate it
- // after duplicating stderr to pickup the proper fd. Otherwise keep the
- // "natual" order of duplicate() calls, so if stderr is redirected to
- // stdout it picks up the proper fd as well.
- //
- if (out == STDERR_FILENO)
- {
- if (err != STDERR_FILENO)
- duplicate (STDERR_FILENO, err, in_efd);
-
- if (out != STDOUT_FILENO)
- duplicate (STDOUT_FILENO, out, in_ofd);
- }
- else
- {
- if (out != STDOUT_FILENO)
- duplicate (STDOUT_FILENO, out, in_ofd);
-
- if (err != STDERR_FILENO)
- duplicate (STDERR_FILENO, err, in_efd);
- }
-
- // Change current working directory if requested.
- //
- if (cwd != nullptr && *cwd != '\0' && chdir (cwd) != 0)
- fail (true);
-
- if (execv (pp.effect_string (), const_cast<char**> (&args[0])) == -1)
- fail (true);
- }
- } // Release the lock in parent.
-
- assert (handle != 0); // Shouldn't get here unless in the parent process.
-
- this->out_fd = move (out_fd.out);
- this->in_ofd = move (in_ofd.in);
- this->in_efd = move (in_efd.in);
- }
-
- bool process::
- wait (bool ie)
- {
- if (handle != 0)
- {
- int es;
- int r (waitpid (handle, &es, 0));
- handle = 0; // We have tried.
-
- if (r == -1)
- {
- // If ignore errors then just leave exit nullopt, so it has "no exit
- // information available" semantics.
- //
- if (!ie)
- throw process_error (errno);
- }
- else
- exit = process_exit (es, process_exit::as_status);
- }
-
- return exit && exit->normal () && exit->code () == 0;
- }
-
- bool process::
- try_wait ()
- {
- if (handle != 0)
- {
- int es;
- int r (waitpid (handle, &es, WNOHANG));
-
- if (r == 0) // Not exited yet.
- return false;
-
- handle = 0; // We have tried.
-
- if (r == -1)
- throw process_error (errno);
-
- exit = process_exit (es, process_exit::as_status);
- }
-
- return true;
- }
-
- process::id_type process::
- current_id ()
- {
- return getpid ();
- }
-
- // process_exit
- //
- process_exit::
- process_exit (code_type c)
- //
- // Note that such an initialization is not portable as POSIX doesn't
- // specify the bits layout for the value returned by waitpid(). However
- // for the major POSIX systems (Linux, FreeBSD, MacOS) it is the
- // following:
- //
- // [0, 7) - terminating signal
- // [7, 8) - coredump flag
- // [8, 16) - program exit code
- //
- // Also the lowest 7 bits value is used to distinguish the normal and
- // abnormal process terminations. If it is zero then the program exited
- // normally and the exit code is available.
- //
- : status (c << 8)
- {
- }
-
- // Make sure the bits layout we stick to (read above) correlates to the W*()
- // macros implementations for the current platform.
- //
- namespace details
- {
- // W* macros may require an argument to be lvalue (for example for glibc).
- //
- static const process_exit::status_type status_code (0xFF00);
-
- static_assert (WIFEXITED (status_code) &&
- WEXITSTATUS (status_code) == 0xFF &&
- !WIFSIGNALED (status_code),
- "unexpected process exit status bits layout");
- }
-
- bool process_exit::
- normal () const
- {
- return WIFEXITED (status);
- }
-
- process_exit::code_type process_exit::
- code () const
- {
- assert (normal ());
- return WEXITSTATUS (status);
- }
-
- int process_exit::
- signal () const
- {
- assert (!normal ());
-
- // WEXITSTATUS() and WIFSIGNALED() can both return false for the same
- // status, so we have neither exit code nor signal. We return zero for
- // such a case.
- //
- return WIFSIGNALED (status) ? WTERMSIG (status) : 0;
- }
-
- bool process_exit::
- core () const
- {
- assert (!normal ());
-
- // Not a POSIX macro (available on Linux, FreeBSD, MacOS).
- //
-#ifdef WCOREDUMP
- return WIFSIGNALED (status) && WCOREDUMP (status);
-#else
- return false;
-#endif
- }
-
- string process_exit::
- description () const
- {
- assert (!normal ());
-
- // It would be convenient to use strsignal() or sys_siglist[] to obtain a
- // signal name for the number, but the function is not thread-safe and the
- // array is not POSIX. So we will use the custom mapping of POSIX signals
- // (IEEE Std 1003.1-2008, 2016 Edition) to their names (as they appear in
- // glibc).
- //
- switch (signal ())
- {
- case SIGHUP: return "hangup (SIGHUP)";
- case SIGINT: return "interrupt (SIGINT)";
- case SIGQUIT: return "quit (SIGQUIT)";
- case SIGILL: return "illegal instruction (SIGILL)";
- case SIGABRT: return "aborted (SIGABRT)";
- case SIGFPE: return "floating point exception (SIGFPE)";
- case SIGKILL: return "killed (SIGKILL)";
- case SIGSEGV: return "segmentation fault (SIGSEGV)";
- case SIGPIPE: return "broken pipe (SIGPIPE)";
- case SIGALRM: return "alarm clock (SIGALRM)";
- case SIGTERM: return "terminated (SIGTERM)";
- case SIGUSR1: return "user defined signal 1 (SIGUSR1)";
- case SIGUSR2: return "user defined signal 2 (SIGUSR2)";
- case SIGCHLD: return "child exited (SIGCHLD)";
- case SIGCONT: return "continued (SIGCONT)";
- case SIGSTOP: return "stopped (process; SIGSTOP)";
- case SIGTSTP: return "stopped (typed at terminal; SIGTSTP)";
- case SIGTTIN: return "stopped (tty input; SIGTTIN)";
- case SIGTTOU: return "stopped (tty output; SIGTTOU)";
- case SIGBUS: return "bus error (SIGBUS)";
-
- // Unavailabe on MacOS 10.11.
- //
-#ifdef SIGPOLL
- case SIGPOLL: return "I/O possible (SIGPOLL)";
-#endif
-
- case SIGPROF: return "profiling timer expired (SIGPROF)";
- case SIGSYS: return "bad system call (SIGSYS)";
- case SIGTRAP: return "trace/breakpoint trap (SIGTRAP)";
- case SIGURG: return "urgent I/O condition (SIGURG)";
- case SIGVTALRM: return "virtual timer expired (SIGVTALRM)";
- case SIGXCPU: return "CPU time limit exceeded (SIGXCPU)";
- case SIGXFSZ: return "file size limit exceeded (SIGXFSZ)";
-
- case 0: return "status unknown";
- default: return "unknown signal " + to_string (signal ());
- }
- }
-
-#else // _WIN32
-
- static process_path
- path_search (const char* f, const dir_path& fb)
- {
- // Note that there is a similar version for Win32.
-
- typedef path::traits traits;
-
- size_t fn (strlen (f));
-
- // Unless there is already the .exe/.bat extension, then we will need to
- // add it.
- //
- bool ext;
- {
- const char* e (traits::find_extension (f, fn));
- ext = (e == nullptr ||
- (casecmp (e, ".exe") != 0 &&
- casecmp (e, ".bat") != 0 &&
- casecmp (e, ".cmd") != 0));
- }
-
- process_path r (f, path (), path ()); // Make sure it is not empty.
- path& rp (r.recall);
- path& ep (r.effect);
-
- // Check that the file exists. Since the executable mode is set according
- // to the file extension, we don't check for that.
- //
- auto exists = [] (const char* f) -> bool
- {
- struct _stat si;
- return _stat (f, &si) == 0 && S_ISREG (si.st_mode);
- };
-
- // Check with extensions: .exe, .cmd, and .bat.
- //
- auto exists_ext = [&exists] (string& s) -> bool
- {
- size_t i (s.size () + 1); // First extension letter.
-
- s += ".exe";
- if (exists (s.c_str ()))
- return true;
-
- s[i] = 'c'; s[i + 1] = 'm'; s[i + 2] = 'd';
- if (exists (s.c_str ()))
- return true;
-
- s[i] = 'b'; s[i + 1] = 'a'; s[i + 2] = 't';
- return exists (s.c_str ());
- };
-
- auto search = [&ep, f, fn, ext, &exists, &exists_ext] (
- const char* d, size_t dn, bool norm = false) -> bool
- {
- string s (move (ep).string ()); // Reuse buffer.
-
- if (dn != 0)
- {
- s.assign (d, dn);
-
- if (!traits::is_separator (s.back ()))
- s += traits::directory_separator;
- }
-
- s.append (f, fn);
- ep = path (move (s)); // Move back into result.
-
- if (norm)
- ep.normalize ();
-
- if (!ext)
- return exists (ep.string ().c_str ());
-
- // Try with the extensions.
- //
- s = move (ep).string ();
- bool e (exists_ext (s));
- ep = path (move (s));
- return e;
- };
-
- // If there is a directory component in the file, then the PATH search
- // does not apply. If the path is relative, then prepend CWD. In both
- // cases we may still need to append the extension and make sure the file
- // actually exists.
- //
- if (traits::find_separator (f, fn) != nullptr)
- {
- if (traits::absolute (f, fn))
- {
- bool e;
- if (!ext)
- e = exists (r.effect_string ());
- else
- {
- string s (f, fn);
- e = exists_ext (s);
- ep = path (move (s));
- }
-
- if (e)
- return r;
- }
- else
- {
- const string& d (traits::current_directory ());
-
- if (search (d.c_str (), d.size (), true)) // Appends extension.
- return r;
- }
-
- return process_path ();
- }
-
- // The search order is documented in CreateProcess(). First we look in the
- // directory of the parent executable.
- //
- {
- char d[_MAX_PATH + 1];
- DWORD n (GetModuleFileName (NULL, d, _MAX_PATH + 1));
-
- if (n == 0 || n == _MAX_PATH + 1) // Failed or truncated.
- throw process_error (last_error_msg ());
-
- const char* p (traits::rfind_separator (d, n));
- assert (p != nullptr);
-
- if (search (d, p - d + 1)) // Include trailing slash.
- {
- // In this case we have to set the recall path.
- //
- // Note that the directory we have extracted is always absolute but
- // the parent's recall path (argv[0]) might be relative. It seems,
- // ideally, we would want to use parent's argv[0] dir (if any) to form
- // the recall path. In particular, if the parent has no directory,
- // then it means it was found via the standard search (e.g., PATH) and
- // then so should the child.
- //
- // How do we get the parent's argv[0]? Luckily, here is __argv on
- // Windows.
- //
- const char* d (__argv[0]);
- size_t n (strlen (d));
- if (const char* p = traits::rfind_separator (d, n))
- {
- string s (d, p - d + 1); // Include trailing slash.
- s.append (f, fn);
- rp = path (move (s));
-
- // If recall is the same as effective, then set effective to empty.
- //
- if (rp == ep)
- ep.clear ();
- }
-
- return r;
- }
- }
-
- // Next look in the current working directory. Crazy, I know.
- //
- // The recall path is the same as initial, though it might not be a bad
- // idea to prepend .\ for clarity.
- //
- {
- const string& d (traits::current_directory ());
-
- if (search (d.c_str (), d.size ()))
- return r;
- }
-
- // Now search in PATH. Recall is unchanged.
- //
- for (const char* b (getenv ("PATH")), *e;
- b != nullptr;
- b = (e != nullptr ? e + 1 : e))
- {
- e = strchr (b, traits::path_separator);
-
- // Empty path (i.e., a double colon or a colon at the beginning or end
- // of PATH) means search in the current directory. Silently skip invalid
- // paths.
- //
- try
- {
- if (search (b, e != nullptr ? e - b : strlen (b)))
- return r;
- }
- catch (const invalid_path&)
- {
- }
- }
-
- // Finally, if we were given a fallback, try that. This case is similar to
- // searching in the parent executable's directory.
- //
- if (!fb.empty ())
- {
- // I would have been nice to preserve trailing slash (by using
- // representation() instead of string()), but that would involve a
- // copy. Oh, well, can't always win.
- //
- if (search (fb.string ().c_str (), fb.string ().size ()))
- {
- // In this case we have to set the recall path. At least here we got
- // to keep the original slash.
- //
- rp = fb;
- rp /= f;
-
- // If recall is the same as effective, then set effective to empty.
- //
- if (rp == ep)
- ep.clear ();
-
- return r;
- }
- }
-
- // Did not find anything.
- //
- return process_path ();
- }
-
- class auto_handle
- {
- public:
- explicit
- auto_handle (HANDLE h = INVALID_HANDLE_VALUE) noexcept: handle_ (h) {}
-
- auto_handle (const auto_handle&) = delete;
- auto_handle& operator= (const auto_handle&) = delete;
-
- ~auto_handle () noexcept {reset ();}
-
- HANDLE
- get () const noexcept {return handle_;}
-
- HANDLE
- release () noexcept
- {
- HANDLE r (handle_);
- handle_ = INVALID_HANDLE_VALUE;
- return r;
- }
-
- void
- reset (HANDLE h = INVALID_HANDLE_VALUE) noexcept
- {
- if (handle_ != INVALID_HANDLE_VALUE)
- {
- bool r (CloseHandle (handle_));
-
- // The valid process, thread or file handle that has no IO operations
- // being performed on it should close successfully, unless something
- // is severely damaged.
- //
- assert (r);
- }
-
- handle_ = h;
- }
-
- private:
- HANDLE handle_;
- };
-
- // Make handles inheritable. The process_spawn_mutex must be pre-acquired for
- // exclusive access. Revert handles inheritability state in destructor.
- //
- // There is a period of time when the process ctor makes file handles it
- // passes to the child to be inheritable, that otherwise are not inheritable
- // by default. During this time these handles can also be inherited by other
- // (irrelevant) child processed spawned from other threads. That can lead to
- // some unwanted consequences, such as inability to delete a file
- // corresponding to such a handle until all childs, that the handle leaked
- // into, terminate. To prevent this behavior the specific sequence of steps
- // (that involves making handles inheritable, spawning process and reverting
- // handles to non-inheritable state back) will be performed after aquiring
- // the process_spawn_mutex (that is released afterwards).
- //
- class inheritability_guard
- {
- public:
- // Require the proof that the mutex is pre-acquired for exclusive access.
- //
- inheritability_guard (const ulock&) {}
-
- ~inheritability_guard ()
- {
- for (auto h: handles_)
- inheritable (h, false); // Can't throw.
- }
-
- void
- inheritable (HANDLE h)
- {
- inheritable (h, true); // Can throw.
- handles_.push_back (h);
- }
-
- private:
- void
- inheritable (HANDLE h, bool state)
- {
- if (!SetHandleInformation (
- h, HANDLE_FLAG_INHERIT, state ? HANDLE_FLAG_INHERIT : 0))
- {
- if (state)
- throw process_error (last_error_msg ());
-
- // We should be able to successfully reset the HANDLE_FLAG_INHERIT flag
- // that we successfully set, unless something is severely damaged.
- //
- assert (false);
- }
- }
-
- private:
- small_vector<HANDLE, 3> handles_;
- };
-
- process::
- process (const char* cwd,
- const process_path& pp, const char* args[],
- int in, int out, int err)
- {
- // Figure out if this is a batch file since running them requires starting
- // cmd.exe and passing the batch file as an argument (see CreateProcess()
- // for deails).
- //
- const char* batch (nullptr);
- {
- const char* p (pp.effect_string ());
- const char* e (path::traits::find_extension (p, strlen (p)));
- if (e != nullptr && (casecmp (e, ".bat") == 0 ||
- casecmp (e, ".cmd") == 0))
- {
- batch = getenv ("COMSPEC");
-
- if (batch == nullptr)
- batch = "C:\\Windows\\System32\\cmd.exe";
- }
- }
-
- fdpipe out_fd;
- fdpipe in_ofd;
- fdpipe in_efd;
-
- auto open_pipe = [] () -> fdpipe
- {
- try
- {
- return fdopen_pipe ();
- }
- catch (const ios_base::failure&)
- {
- // Translate to process_error.
- //
- // For old versions of g++ (as of 4.9) ios_base::failure is not derived
- // from system_error and so we cannot recover the errno value. On the
- // other hand the only possible values are EMFILE and ENFILE. Lets use
- // EMFILE as the more probable. Also let's make no distinction for VC.
- // This is a temporary code after all.
- //
- throw process_error (EMFILE);
- }
- };
-
- auto fail = [](const char* m = nullptr)
- {
- throw process_error (m == nullptr ? last_error_msg () : m);
- };
-
- auto open_null = [] () -> auto_fd
- {
- // Note that we are using a faster, temporary file-based emulation of
- // NUL since we have no way of making sure the child buffers things
- // properly (and by default they seem no to).
- //
- try
- {
- return fdnull (true);
- }
- catch (const ios_base::failure& e)
- {
- // Translate to process_error.
- //
- // For old versions of g++ (as of 4.9) ios_base::failure is not derived
- // from system_error and so we cannot recover the errno value. Lets use
- // EIO in this case. This is a temporary code after all.
- //
- const system_error* se (dynamic_cast<const system_error*> (&e));
-
- throw process_error (se != nullptr
- ? se->code ().value ()
- : EIO);
- }
- };
-
- // If we are asked to open null (-2) then open "half-pipe".
- //
- if (in == -1)
- out_fd = open_pipe ();
- else if (in == -2)
- out_fd.in = open_null ();
-
- if (out == -1)
- in_ofd = open_pipe ();
- else if (out == -2)
- in_ofd.out = open_null ();
-
- if (err == -1)
- in_efd = open_pipe ();
- else if (err == -2)
- in_efd.out = open_null ();
-
- // Create the process.
- //
-
- // Serialize the arguments to string.
- //
- string cmd_line;
- {
- auto append = [&cmd_line] (const string& a)
- {
- if (!cmd_line.empty ())
- cmd_line += ' ';
-
- // On Windows we need to protect values with spaces using quotes.
- // Since there could be actual quotes in the value, we need to escape
- // them.
- //
- bool quote (a.empty () || a.find (' ') != string::npos);
-
- if (quote)
- cmd_line += '"';
-
- for (size_t i (0); i < a.size (); ++i)
- {
- if (a[i] == '"')
- cmd_line += "\\\"";
- else
- cmd_line += a[i];
- }
-
- if (quote)
- cmd_line += '"';
- };
-
- if (batch != nullptr)
- {
- append (batch);
- append ("/c");
- append (pp.effect_string ());
- }
-
- for (const char* const* p (args + (batch != nullptr ? 1 : 0));
- *p != 0;
- ++p)
- append (*p);
- }
-
- // Prepare other process information.
- //
- STARTUPINFO si;
- PROCESS_INFORMATION pi;
- memset (&si, 0, sizeof (STARTUPINFO));
- memset (&pi, 0, sizeof (PROCESS_INFORMATION));
-
- si.cb = sizeof (STARTUPINFO);
- si.dwFlags |= STARTF_USESTDHANDLES;
-
- {
- ulock l (process_spawn_mutex);
- inheritability_guard ig (l);
-
- // Resolve file descriptor to HANDLE and make sure it is inherited. Note
- // that the handle is closed either when CloseHandle() is called for it
- // or when _close() is called for the associated file descriptor. Make
- // sure that either the original file descriptor or the resulting HANDLE
- // is closed but not both of them.
- //
- auto get_osfhandle = [&fail, &ig] (int fd) -> HANDLE
- {
- HANDLE h (reinterpret_cast<HANDLE> (_get_osfhandle (fd)));
- if (h == INVALID_HANDLE_VALUE)
- fail ("unable to obtain file handle");
-
- // Make the handle inheritable by the child unless it is already
- // inheritable.
- //
- DWORD f;
- if (!GetHandleInformation (h, &f))
- fail ();
-
- // Note that the flag check is essential as SetHandleInformation()
- // fails for standard handles and their duplicates.
- //
- if ((f & HANDLE_FLAG_INHERIT) == 0)
- ig.inheritable (h);
-
- return h;
- };
-
- si.hStdInput = in == -1 || in == -2
- ? get_osfhandle (out_fd.in.get ())
- : (in == STDIN_FILENO
- ? GetStdHandle (STD_INPUT_HANDLE)
- : get_osfhandle (in));
-
- si.hStdOutput = out == -1 || out == -2
- ? get_osfhandle (in_ofd.out.get ())
- : (out == STDOUT_FILENO
- ? GetStdHandle (STD_OUTPUT_HANDLE)
- : get_osfhandle (out));
-
- si.hStdError = err == -1 || err == -2
- ? get_osfhandle (in_efd.out.get ())
- : (err == STDERR_FILENO
- ? GetStdHandle (STD_ERROR_HANDLE)
- : get_osfhandle (err));
-
- // Perform standard stream redirection if requested.
- //
- if (err == STDOUT_FILENO)
- si.hStdError = si.hStdOutput;
- else if (out == STDERR_FILENO)
- si.hStdOutput = si.hStdError;
-
- if (err == STDIN_FILENO ||
- out == STDIN_FILENO ||
- in == STDOUT_FILENO ||
- in == STDERR_FILENO)
- fail ("invalid file descriptor");
-
- // Ready for some "Fun with Windows"(TM)? Here is what's in today's
- // episode: MSYS2 (actually, Cygwin) tries to emulate POSIX fork() on
- // Win32 via some pretty heavy hackery. As a result it makes a bunch of
- // assumptions such as that the child process will have the same virtual
- // memory position as the parent and that nobody interferes in its
- // child-parent dance.
- //
- // This, however, doesn't always pan out: for reasons unknown Windows
- // sometimes decides to start the child somewhere else (or, as Cygwin
- // FAQ puts it: "sometimes Windows sets up a process environment that is
- // even more hostile to fork() than usual"). Also things like Windows
- // Defender (collectively called Big List Of Dodgy Apps/BLODA in Cygwin
- // speak) do interfere in all kinds of ways.
- //
- // We also observe another issue that seem related: if we run multiple
- // MSYS2-based applications in parallel (either from the same process
- // or from several processes), then they sometimes terminate abnormally
- // (but quietly, without printing any of the cygheap/fork diagnostics)
- // with status 0xC0000142 (STATUS_DLL_INIT_FAILED).
- //
- // Cygwin FAQ suggests the following potential solutions:
- //
- // 1. Restart the process hoping things will pan out next time around.
- //
- // 2. Eliminate/disable programs from BLODA (disabling Defender helps
- // a lot but not entirely).
- //
- // 3. Apparently switching from 32 to 64-bit should help (less chance
- // for address collisions).
- //
- // 4. Rebase all the Cygwin DLLs (this is a topic for a another episode).
- //
- // To add to this list, we also have our own remedy (which is not
- // generally applicable):
- //
- // 5. Make sure processes that you start don't need to fork. A good
- // example would be tar that runs gz/bzip2/xz. Instead, we start and
- // pipe them ourselves.
- //
- // So what's coming next is a hack that implements remedy #1: after
- // starting the process we wait a bit (50ms) and check if it has
- // terminated with STATUS_DLL_INIT_FAILED (the assumption here is that
- // if this happens, it happens quickly). We then retry starting the
- // process for up to a second.
- //
- // One way to improve this implementation would be to only do it for
- // MSYS2-based programs, for example, by checking (EnumProcessModules())
- // if the process loaded the msys-2.0.dll (not clear though if it will
- // be in the returned list if it has failed to initialize). With this
- // improvement we could then wait longer and try harder.
- //
- optional<bool> msys; // Absent if we don't know.
-
- for (size_t ret (0); ret != 5; ++ret)
- {
- if (!CreateProcess (
- batch != nullptr ? batch : pp.effect_string (),
- const_cast<char*> (cmd_line.c_str ()),
- 0, // Process security attributes.
- 0, // Primary thread security attributes.
- true, // Inherit handles.
- 0, // Creation flags.
- 0, // Use our environment.
- cwd != nullptr && *cwd != '\0' ? cwd : nullptr,
- &si,
- &pi))
- fail ();
-
- auto_handle (pi.hThread).reset (); // Close.
-
- // Detect if this is an MSYS2 process by checking if the process has
- // loaded msys-2.0.dll.
- //
- size_t wait (200);
-
- if (!msys)
- {
- // Wait a bit for the process to load its DLLs.
- //
- if (WaitForSingleObject (pi.hProcess, 50) == WAIT_TIMEOUT)
- {
- wait -= 50;
-
- DWORD mn;
- HMODULE ms[32]; // Normally it is one of the first.
-
- if (EnumProcessModules (pi.hProcess, ms, sizeof (ms), &mn))
- {
- for (DWORD i (0); !msys && i != mn / sizeof (HMODULE); ++i)
- {
- char p[_MAX_PATH + 1];
- if (GetModuleFileNameExA (pi.hProcess, ms[i], p, sizeof (p)))
- {
- size_t n (strlen (p));
- if (n >= 12 && casecmp (p + n - 12, "msys-2.0.dll") == 0)
- msys = true;
- }
- }
-
- if (!msys)
- msys = false;
- }
- // EnumProcessModules() failed (presumably because the process has
- // already exited), fall through.
- }
- // Process exited, fall through.
- }
-
- if (msys && !*msys)
- break;
-
- // Wait a bit longer and check if the process has terminated. If it is
- // still running then we assume all is good. Otherwise, retry if this
- // is the DLL initialization error.
- //
- DWORD s;
- if (WaitForSingleObject (pi.hProcess, wait) != WAIT_OBJECT_0 ||
- !GetExitCodeProcess (pi.hProcess, &s) ||
- s != STATUS_DLL_INIT_FAILED)
- break;
- }
- } // Revert handles back to non-inheritable and release the lock.
-
- // 0 has a special meaning denoting a terminated process handle.
- //
- this->handle = pi.hProcess;
- assert (this->handle != 0 && this->handle != INVALID_HANDLE_VALUE);
-
- this->out_fd = move (out_fd.out);
- this->in_ofd = move (in_ofd.in);
- this->in_efd = move (in_efd.in);
- }
-
- bool process::
- wait (bool ie)
- {
- if (handle != 0)
- {
- DWORD es;
- DWORD e (NO_ERROR);
- if (WaitForSingleObject (handle, INFINITE) != WAIT_OBJECT_0 ||
- !GetExitCodeProcess (handle, &es))
- e = GetLastError ();
-
- auto_handle h (handle); // Auto-deleter.
- handle = 0; // We have tried.
-
- if (e == NO_ERROR)
- {
- exit = process_exit ();
- exit->status = es;
- }
- else
- {
- // If ignore errors then just leave exit nullopt, so it has "no exit
- // information available" semantics.
- //
- if (!ie)
- throw process_error (error_msg (e));
- }
- }
-
- return exit && exit->normal () && exit->code () == 0;
- }
-
- bool process::
- try_wait ()
- {
- if (handle != 0)
- {
- DWORD r (WaitForSingleObject (handle, 0));
- if (r == WAIT_TIMEOUT)
- return false;
-
- DWORD es;
- DWORD e (NO_ERROR);
- if (r != WAIT_OBJECT_0 || !GetExitCodeProcess (handle, &es))
- e = GetLastError ();
-
- auto_handle h (handle);
- handle = 0; // We have tried.
-
- if (e != NO_ERROR)
- throw process_error (error_msg (e));
-
- exit = process_exit ();
- exit->status = es;
- }
-
- return true;
- }
-
- process::id_type process::
- id () const
- {
- id_type r (GetProcessId (handle));
-
- if (r == 0)
- throw process_error (last_error_msg ());
-
- return r;
- }
-
- process::id_type process::
- current_id ()
- {
- return GetCurrentProcessId ();
- }
-
- // process_exit
- //
- process_exit::
- process_exit (code_type c)
- //
- // The NTSTATUS value returned by GetExitCodeProcess() has the following
- // layout of bits:
- //
- // [ 0, 16) - program exit code or exception code
- // [16, 29) - facility
- // [29, 30) - flag indicating if the status value is customer-defined
- // [30, 31) - severity (00 -success, 01 - informational, 10 - warning,
- // 11 - error)
- //
- : status (c)
- {
- }
-
- bool process_exit::
- normal () const
- {
- // We consider status values with severities other than 0 not being
- // returned by the process and so denoting the abnormal termination.
- //
- return ((status >> 30) & 0x3) == 0;
- }
-
- process_exit::code_type process_exit::
- code () const
- {
- assert (normal ());
- return status & 0xFFFF;
- }
-
- string process_exit::
- description () const
- {
- assert (!normal ());
-
- // Error codes (or, as MSDN calls them, exception codes) are defined in
- // ntstatus.h. It is possible to obtain message descriptions for them
- // using FormatMessage() with the FORMAT_MESSAGE_FROM_HMODULE flag and the
- // handle returned by LoadLibrary("NTDLL.DLL") call. However, the returned
- // messages are pretty much useless being format strings. For example for
- // STATUS_ACCESS_VIOLATION error code the message string is "The
- // instruction at 0x%p referenced memory at 0x%p. The memory could not be
- // %s.". Also under Wine (1.9.8) it is not possible to obtain such a
- // descriptions at all for some reason.
- //
- // Let's use a custom code-to-message mapping for the most common error
- // codes, and extend it as needed.
- //
- // Note that the error code most likely will be messed up if the abnormal
- // termination of a process is intercepted with the "searching for
- // available solution" message box or debugger invocation. Also note that
- // the same failure can result in different exit codes for a process being
- // run on Windows nativelly and under Wine. For example under Wine 1.9.8 a
- // process that fails due to the stack overflow exits normally with 0
- // status but prints the "err:seh:setup_exception stack overflow ..."
- // message to stderr.
- //
- switch (status)
- {
- case STATUS_ACCESS_VIOLATION: return "access violation";
- case STATUS_DLL_INIT_FAILED: return "DLL initialization failed";
- case STATUS_INTEGER_DIVIDE_BY_ZERO: return "integer divided by zero";
-
- // VC-compiled program that calls abort() terminates with this error code
- // (0xC0000409). That differs from MinGW GCC-compiled one, that exits
- // normally with status 3 (conforms to MSDN). Under Wine (1.9.8) such a
- // program exits with status 3 for both VC and MinGW GCC. Sounds weird.
- //
- case STATUS_STACK_BUFFER_OVERRUN: return "stack buffer overrun";
- case STATUS_STACK_OVERFLOW: return "stack overflow";
-
- default:
- {
- string desc ("unknown error 0x");
-
- // Add error code hex representation (as it is defined in ntstatus.h).
- //
- // Strange enough, there is no easy way to convert a number into the
- // hex string representation (not using streams).
- //
- const char digits[] = "0123456789ABCDEF";
- bool skip (true); // Skip leading zeros.
-
- auto add = [&desc, &digits, &skip] (unsigned char d, bool force)
- {
- if (d != 0 || !skip || force)
- {
- desc += digits[d];
- skip = false;
- }
- };
-
- for (int i (sizeof (status) - 1); i >= 0 ; --i)
- {
- unsigned char c ((status >> (i * 8)) & 0xFF);
- add ((c >> 4) & 0xF, false); // Convert the high 4 bits to a digit.
- add (c & 0xF, i == 0); // Convert the low 4 bits to a digit.
- }
-
- return desc;
- }
- }
- }
-
-#endif // _WIN32
-}