202 lines
6.6 KiB
C++
202 lines
6.6 KiB
C++
/*
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Copyright (C) 2010 Paul Davis
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Author: Robin Gareus <robin@gareus.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef __ardour_system_exec_h__
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#define __ardour_system_exec_h__
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#ifndef STDIN_FILENO
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#define STDIN_FILENO 0
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#endif
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#ifndef STDOUT_FILENO
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#define STDOUT_FILENO 1
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#endif
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#ifndef STDERR_FILENO
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#define STDERR_FILENO 2
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#endif
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#include <string>
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#include <pthread.h>
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#include <signal.h>
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#ifdef NOPBD /* outside ardour */
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#include <sigc++/bind.h>
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#include <sigc++/signal.h>
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#else
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#include <pbd/signals.h>
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#endif
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/** @class: SystemExec
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* @brief execute an external command
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*
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* This class allows launche an external command-line application
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* opening a full-duplex connection to its standard I/O.
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*
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* In Ardour context it is used to launch xjadeo and ffmpeg.
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*
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* The \ref write_to_stdin function provides for injecting data into STDIN
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* of the child-application while output of the program to STDOUT/STDERR is
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* forwarded using the \ref ReadStdout signal.
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* \ref Terminated is sent if the child application exits.
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*
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*/
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class SystemExec
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{
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public:
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/** prepare execution of a program with 'execve'
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*
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* This function takes over the existing environment variable and provides
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* an easy way to speciy command-line arguments for the new process.
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*
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* Note: The argument parser does not interpret quotation-marks and splits
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* arugments on whitespace. The argument string can be empty.
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* The alternative constructor below allows to specify quoted parameters
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* incl. whitespace.
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*
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* @param c program pathname that identifies the new process image file.
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* @param a string of commandline-arguments to be passed to the new program.
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*/
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SystemExec (std::string c, std::string a = "");
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/** similar to \ref SystemExec but allows to specify custom arguments
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*
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* @param c program pathname that identifies the new process image file.
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* @param a array of argument strings passed to the new program as 'argv'.
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* it must be terminated by a null pointer (see the 'evecve'
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* POSIX-C documentation for more information)
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* The array must be dynamically allocated using malloc or strdup.
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* Unless they're NULL, the array itself and each of its content
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* memory is freed() in the destructor.
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*
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*/
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SystemExec (std::string c, char ** a);
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virtual ~SystemExec ();
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/** fork and execute the given program
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*
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* @param stderr_mode select what to do with program's standard error
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* output:
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* '0': keep STDERR; mix it with parent-process' STDERR
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* '1': ignore STDERR of child-program
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* '2': merge STDERR into STDOUT and send it with the
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* ReadStdout signal.
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* @return If the process is already running or was launched successfully
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* the function returns zero (0). A negative number indicates an error.
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*/
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int start (int stderr_mode = 1);
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/** kill running child-process
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*
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* if a child process exists trt to shut it down by closing its STDIN.
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* if the program dies not react try SIGTERM and eventually SIGKILL
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*/
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void terminate ();
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/** check if the child programm is (still) running.
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*
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* This function calls waitpid(WNOHANG) to check the state of the
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* child-process.
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* @return true if the program is (still) running.
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*/
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bool is_running ();
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/** call the waitpid system-call with the pid of the child-program
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*
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* Basically what \ref terminate uses internally.
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*
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* This function is only useful if you want to control application
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* termination yourself (eg timeouts or progress-dialog).
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* @param option flags - see waitpid manual
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* @return status info from waitpid call (not waitpid's return value)
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* or -1 if the child-program is not running.
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*/
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int wait (int options=0);
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/** closes both STDIN and STDOUT connections to/from
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* the child-program.
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* With the output-interposer thread gone, the program
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* should terminate.
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* used by \ref terminate()
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*/
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void close_stdin ();
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/** write into child-program's STDIN
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* @param d data to write
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* @param len length of data to write, if it is 0 (zero), d.length() is
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* used to determine the number of bytes to transmit.
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* @return number of bytes written.
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*/
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int write_to_stdin (std::string d, size_t len=0);
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/** The ReadStdout signal is emitted when the application writes to STDOUT.
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* it passes the written data and its length in bytes as arguments to the bound
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* slot(s).
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*/
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#ifdef NOPBD /* outside ardour */
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sigc::signal<void, std::string,size_t> ReadStdout;
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#else
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PBD::Signal2<void, std::string,size_t> ReadStdout;
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#endif
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/** The Terminated signal is emitted when application terminates. */
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#ifdef NOPBD /* outside ardour */
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sigc::signal<void> Terminated;
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#else
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PBD::Signal0<void> Terminated;
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#endif
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/** interposer to emit signal for writes to STDOUT/ERR.
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*
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* Thread that reads the stdout of the forked
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* process and signal-sends it to the main thread.
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* It also emits the Terminated() signal once
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* the the forked process closes it's stdout.
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*
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* Note: it's actually 'private' function but used
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* by the internal pthread, which only has a pointer
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* to this instance and thus can only access public fn.
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*/
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void output_interposer ();
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protected:
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std::string cmd; ///< path to command - set when creating the class
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int nicelevel; ///< process nice level - defaults to 0
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void make_argp(std::string);
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void make_envp();
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char **argp;
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char **envp;
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private:
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#ifdef __WIN32__
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PROCESS_INFORMATION *pid;
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HANDLE stdinP[2];
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HANDLE stdoutP[2];
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HANDLE stderrP[2];
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char *w_args;
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void make_wargs(char **);
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#else
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pid_t pid;
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#endif
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pthread_mutex_t write_lock;
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int fdin; ///< file-descriptor for writing to child's STDIN. This variable is identical to pin[1] but also used as status check if the stdin pipe is open: <0 means closed.
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int pok[2];
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int pin[2];
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int pout[2];
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pthread_t thread_id_tt;
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bool thread_active;
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};
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#endif /* __ardour_system_exec_h__ */
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