KProcess Class Reference
#include <kprocess.h>
Inheritance diagram for KProcess:

Detailed Description
Child process invocation, monitoring and control.
General usage and features:
This class allows a KDE application to start child processes without having to worry about UN*X signal handling issues and zombie process reaping.
- See also:
- KProcIO
- DontCare -- The child process is invoked and both the child process and the parent process continue concurrently.
- NotifyOnExit -- The child process is invoked and both the child and the parent process run concurrently.
Be aware: When the KProcess object gets destructed, the child process will be killed if it is still running! This means in particular, that it usually makes no sense to use a KProcess on the stack with NotifyOnExit.
- OwnGroup -- like NotifyOnExit, but the child process is started in an own process group (and an own session, FWIW). The behavior of kill() changes to killing the whole process group - this makes this mode useful for implementing primitive job management. It can be used to work around broken wrapper scripts that don't propagate signals to the "real" program. However, use this with care, as you disturb the shell's job management if your program is started from the command line.
- Block -- The child process starts and the parent process is suspended until the child process exits. (Really not recommended for programs with a GUI.) In this mode the parent can read the child's output, but can't send it any input.
Furthermore it is possible to supply command-line arguments to the process in a clean fashion (no null-terminated stringlists and such...)
A small usage example:
KProcess *proc = new KProcess; *proc << "my_executable"; *proc << "These" << "are" << "the" << "command" << "line" << "args"; QApplication::connect(proc, SIGNAL(processExited(KProcess *)), pointer_to_my_object, SLOT(my_objects_slot(KProcess *))); proc->start();
This will start "my_executable" with the commandline arguments "These"...
When the child process exits, the slot will be invoked.
Communication with the child process:
KProcess supports communication with the child process through stdin/stdout/stderr.
The following functions are provided for getting data from the child process or sending data to the child's stdin (For more information, have a look at the documentation of each function):
- writeStdin() -- Transmit data to the child process' stdin. When all data was sent, the signal wroteStdin() is emitted.
- When data arrives at stdout or stderr, the signal receivedStdout() resp. receivedStderr() is emitted.
- You can shut down individual communication channels with closeStdin(), closeStdout(), and closeStderr(), resp.
- Author:
- Christian Czezatke e9025461@student.tuwien.ac.at
Definition at line 124 of file kprocess.h.
Public Types | |
enum | Communication { NoCommunication = 0, Stdin = 1, Stdout = 2, Stderr = 4, AllOutput = 6, All = 7, NoRead = 8, CTtyOnly = NoRead, MergedStderr = 16 } |
enum | RunMode { DontCare, NotifyOnExit, Block, OwnGroup } |
enum | { PrioLowest = 20, PrioLow = 10, PrioLower = 5, PrioNormal = 0, PrioHigher = -5, PrioHigh = -10, PrioHighest = -19 } |
Signals | |
void | processExited (KProcess *proc) |
void | receivedStdout (KProcess *proc, char *buffer, int buflen) |
void | receivedStdout (int fd, int &len) |
void | receivedStderr (KProcess *proc, char *buffer, int buflen) |
void | wroteStdin (KProcess *proc) |
Public Member Functions | |
KProcess (QObject *parent, const char *name=0) | |
KProcess () | |
virtual | ~KProcess () |
bool | setExecutable (const QString &proc) KDE_DEPRECATED |
KProcess & | operator<< (const QString &arg) |
KProcess & | operator<< (const char *arg) |
KProcess & | operator<< (const QCString &arg) |
KProcess & | operator<< (const QStringList &args) |
void | clearArguments () |
virtual bool | start (RunMode runmode=NotifyOnExit, Communication comm=NoCommunication) |
virtual bool | kill (int signo=SIGTERM) |
bool | isRunning () const |
pid_t | pid () const |
KDE_DEPRECATED pid_t | getPid () const |
void | suspend () |
void | resume () |
bool | wait (int timeout=-1) |
bool | normalExit () const |
bool | signalled () const |
bool | coreDumped () const |
int | exitStatus () const |
int | exitSignal () const |
bool | writeStdin (const char *buffer, int buflen) |
bool | closeStdin () |
bool | closeStdout () |
bool | closeStderr () |
bool | closePty () |
void | closeAll () |
const QValueList< QCString > & | args () |
void | setRunPrivileged (bool keepPrivileges) |
bool | runPrivileged () const |
void | setEnvironment (const QString &name, const QString &value) |
void | setWorkingDirectory (const QString &dir) |
void | setUseShell (bool useShell, const char *shell=0) |
void | detach () |
void | setUsePty (Communication comm, bool addUtmp) |
KPty * | pty () const |
bool | setPriority (int prio) |
Static Public Member Functions | |
static QString | quote (const QString &arg) |
Protected Slots | |
void | slotChildOutput (int fdno) |
void | slotChildError (int fdno) |
void | slotSendData (int dummy) |
Protected Member Functions | |
void | setupEnvironment () |
virtual int | setupCommunication (Communication comm) |
virtual int | commSetupDoneP () |
virtual int | commSetupDoneC () |
virtual void | processHasExited (int state) |
virtual void | commClose () |
void | setBinaryExecutable (const char *filename) |
int | childOutput (int fdno) |
int | childError (int fdno) |
virtual void | virtual_hook (int id, void *data) |
Protected Attributes | |
QValueList< QCString > | arguments |
RunMode | run_mode |
bool | runs |
pid_t | pid_ |
int | status |
bool | keepPrivs |
int | out [2] |
int | in [2] |
int | err [2] |
QSocketNotifier * | innot |
QSocketNotifier * | outnot |
QSocketNotifier * | errnot |
Communication | communication |
const char * | input_data |
int | input_sent |
int | input_total |
Friends | |
class | KProcessController |
Member Enumeration Documentation
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More or less intuitive constants for use with setPriority().
Definition at line 565 of file kprocess.h. |
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Modes in which the communication channel can be opened.
If communication for more than one channel is required, the values have to be or'ed together, for example to get communication with stdout as well as with stdin, you would specify
If
If Definition at line 151 of file kprocess.h. |
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Run-modes for a child process.
Definition at line 163 of file kprocess.h. |
Constructor & Destructor Documentation
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Constructor.
Definition at line 120 of file kprocess.cpp. |
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Constructor.
Definition at line 145 of file kprocess.cpp. |
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Destructor:.
If the process is running when the destructor for this class is called, the child process is killed with a SIGKILL, but only if the run mode is not of type Definition at line 225 of file kprocess.cpp. |
Member Function Documentation
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Lets you see what your arguments are for debugging.
Definition at line 464 of file kprocess.h. |
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Called by slotChildError() this function copies data arriving from the child process' stderr to the respective buffer and emits the signal receivedStderr().
Definition at line 859 of file kprocess.cpp. |
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Called by slotChildOutput() this function copies data arriving from the child process' stdout to the respective buffer and emits the signal receivedStdout().
Definition at line 836 of file kprocess.cpp. |
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Clear a command line argument list that has been set by using operator<<.
Definition at line 293 of file kprocess.cpp. |
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Close stdin, stdout, stderr and the pty. This is the same that calling all close* functions in a row:
Definition at line 717 of file kprocess.cpp. |
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Deletes the optional utmp entry and closes the pty. Make sure to shut down any communication links that are using the pty before calling this function.
Definition at line 702 of file kprocess.cpp. |
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Shuts down the Stderr communication link. If no pty is used, any further attempts by the child to write to its stderr file descriptor will cause it to receive a SIGPIPE.
Definition at line 688 of file kprocess.cpp. |
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Shuts down the Stdin communication link. If no pty is used, this causes "EOF" to be indicated on the child's stdin file descriptor.
Definition at line 660 of file kprocess.cpp. |
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Shuts down the Stdout communication link. If no pty is used, any further attempts by the child to write to its stdout file descriptor will cause it to receive a SIGPIPE.
Definition at line 674 of file kprocess.cpp. |
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Cleans up the communication links to the child after it has exited. This function should act upon the values of pid() and runs. See the kprocess.cpp source for details.
Definition at line 1037 of file kprocess.cpp. |
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Called right after a (successful) fork(), but before an exec() on the child process' side. It usually duplicates the in[0], out[1] and err[1] file handles to the respective standard I/O handles. Definition at line 987 of file kprocess.cpp. |
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Called right after a (successful) fork() on the parent side. This function will usually do some communications cleanup, like closing in[0], out[1] and out[1]. Furthermore, it must also create the QSocketNotifiers innot, outnot and errnot and connect their Qt signals to the respective KProcess slots. For a more detailed explanation, it is best to have a look at the default implementation in kprocess.cpp. Definition at line 942 of file kprocess.cpp. |
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Checks whether a killed process dumped core.
Definition at line 606 of file kprocess.cpp. |
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Detaches KProcess from child process. All communication is closed. No exit notification is emitted any more for the child process. Deleting the KProcess will no longer kill the child process. Note that the current process remains the parent process of the child process. Definition at line 240 of file kprocess.cpp. |
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Returns the signal the process was killed by.
Definition at line 622 of file kprocess.cpp. |
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Returns the exit status of the process.
Definition at line 616 of file kprocess.cpp. |
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Definition at line 317 of file kprocess.h. |
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Checks whether the process is running.
Definition at line 504 of file kprocess.cpp. |
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Stop the process (by sending it a signal).
Definition at line 493 of file kprocess.cpp. |
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Checks whether the process exited cleanly.
Definition at line 594 of file kprocess.cpp. |
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Sets the executable and the command line argument list for this process, in a single method call, or add a list of arguments.
Definition at line 268 of file kprocess.cpp. |
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Similar to previous method, takes a QCString, supposed to be in locale 8 bit already.
Definition at line 276 of file kprocess.cpp. |
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Similar to previous method, takes a char *, supposed to be in locale 8 bit already.
Definition at line 281 of file kprocess.cpp. |
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Sets the executable and the command line argument list for this process. For example, doing an "ls -l /usr/local/bin" can be achieved by: KProcess p; ... p << "ls" << "-l" << "/usr/local/bin"
Definition at line 287 of file kprocess.cpp. |
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Returns the process id of the process. If it is called after the process has exited, it returns the process id of the last child process that was created by this instance of KProcess. Calling it before any child process has been started by this KProcess instance causes pid() to return 0.
Definition at line 511 of file kprocess.cpp. |
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Emitted after the process has terminated when the process was run in the
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Immediately called after a successfully started process in NotifyOnExit mode has exited. This function normally calls commClose() and emits the processExited() signal.
Definition at line 821 of file kprocess.cpp. |
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Obtains the pty object used by this process. The return value is valid only after setUsePty() was used with a non-zero argument. The pty is open only while the process is running.
Definition at line 803 of file kprocess.cpp. |
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This function can be used to quote an argument string such that the shell processes it properly. This is e. g. necessary for user-provided file names which may contain spaces or quotes. It also prevents expansion of wild cards and environment variables.
Reimplemented in KShellProcess. Definition at line 809 of file kprocess.cpp. |
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Emitted, when output from the child process has been received on stderr. To actually get this signal, the Stderr communication link has to be turned on in start().
You should copy the information contained in
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Emitted when output from the child process has been received on stdout. To actually get this signal, the Stdout communication link has to be turned on in start() and the NoRead flag must have been passed. You will need to explicitly call resume() after your call to start() to begin processing data from the child process' stdout. This is to ensure that this signal is not emitted when no one is connected to it, otherwise this signal will not be emitted.
The data still has to be read from file descriptor
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Emitted, when output from the child process has been received on stdout. To actually get this signal, the Stdout communication link has to be turned on in start().
buffer to your private data structures before returning from the slot. Example: QString myBuf = QString::fromLatin1(buffer, buflen); |
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Resume processing of data from stdout of the child process.
Definition at line 654 of file kprocess.cpp. |
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Returns whether the started process will drop any setuid/setgid privileges or whether it will keep them.
Definition at line 204 of file kprocess.cpp. |
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Specify the actual executable that should be started (first argument to execve) Normally the the first argument is the executable but you can override that with this function.
Definition at line 250 of file kprocess.cpp. |
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Adds the variable This function must be called before starting the process.
Definition at line 171 of file kprocess.cpp. |
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Sets the executable to be started with this KProcess object. Returns false if the process is currently running (in that case the executable remains unchanged).
Definition at line 255 of file kprocess.cpp. |
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Sets the scheduling priority of the process.
Definition at line 210 of file kprocess.cpp. |
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Controls whether the started process should drop any setuid/setgid privileges or whether it should keep them. Note that this function is mostly a dummy, as the KDE libraries currently refuse to run with setuid/setgid privileges. The default is false: drop privileges
Definition at line 198 of file kprocess.cpp. |
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This function is called from start() right before a fork() takes place.
According to the This function should return 1 if setting the needed communication channels was successful. The default implementation is to create UNIX STREAM sockets for the communication, but you could reimplement this function to establish a TCP/IP communication for network communication, for example. Definition at line 874 of file kprocess.cpp. |
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Sets up the environment according to the data passed via setEnvironment().
Definition at line 183 of file kprocess.cpp. |
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Specify whether to create a pty (pseudo-terminal) for running the command. This function should be called before starting the process.
Definition at line 790 of file kprocess.cpp. |
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Specify whether to start the command via a shell or directly.
The default is to start the command directly. If When using a shell, the caller should make sure that all filenames etc. are properly quoted when passed as argument.
Definition at line 765 of file kprocess.cpp. |
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Changes the current working directory (CWD) of the process to be started. This function must be called before starting the process.
Definition at line 177 of file kprocess.cpp. |
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Checks whether the process was killed by a signal.
Definition at line 600 of file kprocess.cpp. |
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This slot gets activated when data from the child's stderr arrives. It usually calls childError().
Definition at line 738 of file kprocess.cpp. |
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This slot gets activated when data from the child's stdout arrives. It usually calls childOutput().
Definition at line 731 of file kprocess.cpp. |
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Called when another bulk of data can be sent to the child's stdin. If there is no more data to be sent to stdin currently available, this function must disable the QSocketNotifier innot.
Definition at line 745 of file kprocess.cpp. |
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Starts the process. For a detailed description of the various run modes and communication semantics, have a look at the general description of the KProcess class. Note that if you use setUsePty( Stdout | Stderr, <bool> ), you cannot use Stdout | Stderr here - instead, use Stdout only to receive the mixed output. The following problems could cause this function to return false:
Definition at line 298 of file kprocess.cpp. |
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Suspend processing of data from stdout of the child process.
Definition at line 648 of file kprocess.cpp. |
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Suspend execution of the current thread until the child process dies or the timeout hits. This function is not recommended for programs with a GUI.
Definition at line 528 of file kprocess.cpp. |
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Transmit data to the child process' stdin. This function may return false in the following cases:
buffer or call writeStdin() again until either a wroteStdin() signal indicates that the data has been sent or a processExited() signal shows that the child process is no longer alive.If all the data has been sent to the client, the signal wroteStdin() will be emitted.
Definition at line 628 of file kprocess.cpp. |
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Emitted after all the data that has been specified by a prior call to writeStdin() has actually been written to the child process.
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Friends And Related Function Documentation
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KProcessController is a friend of KProcess because it has to have access to various data members.
Definition at line 877 of file kprocess.h. |
Member Data Documentation
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The list of the process' command line arguments. The first entry in this list is the executable itself. Definition at line 688 of file kprocess.h. |
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Lists the communication links that are activated for the child process. Should not be modified from derived classes. Definition at line 844 of file kprocess.h. |
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The socket descriptors for stderr.
Definition at line 825 of file kprocess.h. |
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The socket notifier for err[0].
Definition at line 838 of file kprocess.h. |
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The socket descriptors for stdin.
Definition at line 821 of file kprocess.h. |
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The socket notifier for in[1].
Definition at line 830 of file kprocess.h. |
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The buffer holding the data that has to be sent to the child.
Definition at line 863 of file kprocess.h. |
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The number of bytes already transmitted.
Definition at line 867 of file kprocess.h. |
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The total length of input_data.
Definition at line 871 of file kprocess.h. |
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If false, the child process' effective uid & gid will be reset to the real values.
Definition at line 726 of file kprocess.h. |
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The socket descriptors for stdout.
Definition at line 817 of file kprocess.h. |
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The socket notifier for out[0].
Definition at line 834 of file kprocess.h. |
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The PID of the currently running process. You should not modify this data member in derived classes. Please use pid() instead of directly accessing this member since it will probably be made private in later versions of KProcess. Definition at line 709 of file kprocess.h. |
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How to run the process (Block, NotifyOnExit, DontCare). You should not modify this data member directly from derived classes. Definition at line 693 of file kprocess.h. |
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true if the process is currently running. You should not modify this data member directly from derived classes. Please use isRunning() for reading the value of this data member since it will probably be made private in later versions of KProcess. Definition at line 700 of file kprocess.h. |
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The process' exit status as returned by waitpid(). You should not modify the value of this data member from derived classes. You should rather use exitStatus() than accessing this data member directly since it will probably be made private in further versions of KProcess. Definition at line 718 of file kprocess.h. |
The documentation for this class was generated from the following files: