403 lines
21 KiB
C
Executable File
403 lines
21 KiB
C
Executable File
/*
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File: GetPID.c
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Description: This file provides a simple API to do process PID lookup based on process name.
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Author: Chad Jones
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Copyright: © Copyright 2003 Apple Computer, Inc. All rights reserved.
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Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Computer, Inc.
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("Apple") in consideration of your agreement to the following terms, and your
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use, installation, modification or redistribution of this Apple software
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constitutes acceptance of these terms. If you do not agree with these terms,
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please do not use, install, modify or redistribute this Apple software.
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In consideration of your agreement to abide by the following terms, and subject
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to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs
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copyrights in this original Apple software (the "Apple Software"), to use,
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reproduce, modify and redistribute the Apple Software, with or without
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modifications, in source and/or binary forms; provided that if you redistribute
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the Apple Software in its entirety and without modifications, you must retain
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this notice and the following text and disclaimers in all such redistributions of
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the Apple Software. Neither the name, trademarks, service marks or logos of
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Apple Computer, Inc. may be used to endorse or promote products derived from the
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Apple Software without specific prior written permission from Apple. Except as
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expressly stated in this notice, no other rights or licenses, express or implied,
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are granted by Apple herein, including but not limited to any patent rights that
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may be infringed by your derivative works or by other works in which the Apple
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Software may be incorporated.
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The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO
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WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
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WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
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COMBINATION WITH YOUR PRODUCTS.
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IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION
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OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT
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(INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN
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ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Change History (most recent first):
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*/
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#include "GetPID.h"
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#include <errno.h>
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#include <string.h>
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#include <sys/sysctl.h>
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/*****************************************************
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* GetAllPIDsForProcessName
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*****************************************************
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* Purpose: This functions purpose is to lookup a BSD
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* process PID given the BSD process name. This function may
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* potentially return multiple PIDs for a given BSD process name
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* since several processes can have the same BSD process name.
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*
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* Parameters:
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* ProcessName A constant C-string. On calling
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* GetAllPIDsForProcessName this variable holds the BSD process name
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* used to do the process lookup. Note that the process name you need
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* to pass is the name of the BSD executable process. If trying
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* to find the PID of an regular OSX application you will need to pass the
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* name of the actual BSD executable inside an application bundle (rather
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* than the bundle name itself). In any case as a user you can find the
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* BSD process name of any process (including OSX applications) by
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* typing the command "ps -axcocommand,pid" in terminal.
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*
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* ArrayOfReturnedPIDs A pointer to a pre-allocated array of pid_t.
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* On calling GetAllPIDsForProcessName this variable must be a pointer to a
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* pre-allocated array of pid_t whos length (in number of pid_t entries) is defined
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* in ArrayOfPIDsLength. On successful return from GetAllPIDsForProcessName
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* this array will hold the PIDs of all processes which have a matching process
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* name to that specified in the ProcessName input variable. The number of actual
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* PIDs entered in the array starting at index zero will be the value returned
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* in NumberOfMatchesFound. On failed return if the error is a buffer overflow
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* error then the buffer will be filled to the max with PIDs which matched.
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* Otherwise on failed return the state of the array will be undefined. Note
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* the returned PID array is not sorted and is listed in order of process encountered.
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*
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* NumberOfPossiblePIDsInArray A unsigned integer. On calling
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* GetAllPIDsForProcessName this variable will hold the number of
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* pre-allocated PID entries which are in the ArrayOfReturnedPIDs for this functions
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* use. Note this value must have a value greater than zero.
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*
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* NumberOfMatchesFound An unsigned integer. On calling GetAllPIDsForProcessName
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* this variable will point to a pre-allocated unsigned integer. On return from
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* GetAllPIDsForProcessName this variable will contain the number of PIDs contained in the
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* ArrayOfReturnedPIDs. On failed return the value of the variable will be undefined.
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*
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* SysctlError A pointer to a pre-allocated integer. On failed return, this
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* variable represents the error returned from the sysctl command. On function
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* success this variable will have a value specified by the sysctl based on the
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* error that occurred. On success the variable will have the value zero.
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* Note this variable can also be NULL in which case the variable is ignored.
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*
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* *Function Result* A integer return value.
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* See result codes listed below.
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* Result Codes:
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* 0 Success. A set of process PIDs were found and are located in
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* ArrayOfReturnedPIDs array.
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* -1 Could not find a process with a matching process name
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* (i.e. process not found).
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* -2 Invalid arguments passed.
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* -3 Unable to get the size of sysctl buffer required
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* (consult SysctlError return value for more information)
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* -4 Unable to allocate memory to store BSD process information
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* (consult SysctlError return value for more information)
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* -5 The array passed to hold the returned PIDs is not large enough
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* to hold all PIDs of process with matching names.
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*
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*****************************************************/
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int GetAllPIDsForProcessName(const char* ProcessName,
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pid_t ArrayOfReturnedPIDs[],
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const unsigned int NumberOfPossiblePIDsInArray,
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unsigned int* NumberOfMatchesFound,
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int* SysctlError)
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{
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// --- Defining local variables for this function and initializing all to zero --- //
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int mib[6] = {0,0,0,0,0,0}; //used for sysctl call.
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int SuccessfullyGotProcessInformation;
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size_t sizeOfBufferRequired = 0; //set to zero to start with.
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int error = 0;
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long NumberOfRunningProcesses = 0;
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unsigned int Counter = 0;
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struct kinfo_proc* BSDProcessInformationStructure = NULL;
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pid_t CurrentExaminedProcessPID = 0;
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char* CurrentExaminedProcessName = NULL;
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// --- Checking input arguments for validity --- //
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if (ProcessName == NULL) //need valid process name
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{
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return(kInvalidArgumentsError);
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}
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if (ArrayOfReturnedPIDs == NULL) //need an actual array
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{
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return(kInvalidArgumentsError);
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}
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if (NumberOfPossiblePIDsInArray <= 0)
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{
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//length of the array must be larger than zero.
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return(kInvalidArgumentsError);
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}
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if (NumberOfMatchesFound == NULL) //need an integer for return.
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{
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return(kInvalidArgumentsError);
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}
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//--- Setting return values to known values --- //
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//initalizing PID array so all values are zero
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memset(ArrayOfReturnedPIDs, 0, NumberOfPossiblePIDsInArray * sizeof(pid_t));
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*NumberOfMatchesFound = 0; //no matches found yet
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if (SysctlError != NULL) //only set sysctlError if it is present
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{
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*SysctlError = 0;
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}
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//--- Getting list of process information for all processes --- //
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/* Setting up the mib (Management Information Base) which is an array of integers where each
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* integer specifies how the data will be gathered. Here we are setting the MIB
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* block to lookup the information on all the BSD processes on the system. Also note that
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* every regular application has a recognized BSD process accociated with it. We pass
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* CTL_KERN, KERN_PROC, KERN_PROC_ALL to sysctl as the MIB to get back a BSD structure with
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* all BSD process information for all processes in it (including BSD process names)
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*/
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mib[0] = CTL_KERN;
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mib[1] = KERN_PROC;
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mib[2] = KERN_PROC_ALL;
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/* Here we have a loop set up where we keep calling sysctl until we finally get an unrecoverable error
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* (and we return) or we finally get a succesful result. Note with how dynamic the process list can
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* be you can expect to have a failure here and there since the process list can change between
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* getting the size of buffer required and the actually filling that buffer.
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*/
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SuccessfullyGotProcessInformation = FALSE;
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while (SuccessfullyGotProcessInformation == FALSE)
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{
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/* Now that we have the MIB for looking up process information we will pass it to sysctl to get the
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* information we want on BSD processes. However, before we do this we must know the size of the buffer to
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* allocate to accomidate the return value. We can get the size of the data to allocate also using the
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* sysctl command. In this case we call sysctl with the proper arguments but specify no return buffer
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* specified (null buffer). This is a special case which causes sysctl to return the size of buffer required.
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*
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* First Argument: The MIB which is really just an array of integers. Each integer is a constant
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* representing what information to gather from the system. Check out the man page to know what
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* constants sysctl will work with. Here of course we pass our MIB block which was passed to us.
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* Second Argument: The number of constants in the MIB (array of integers). In this case there are three.
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* Third Argument: The output buffer where the return value from sysctl will be stored. In this case
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* we don't want anything return yet since we don't yet know the size of buffer needed. Thus we will
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* pass null for the buffer to begin with.
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* Forth Argument: The size of the output buffer required. Since the buffer itself is null we can just
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* get the buffer size needed back from this call.
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* Fifth Argument: The new value we want the system data to have. Here we don't want to set any system
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* information we only want to gather it. Thus, we pass null as the buffer so sysctl knows that
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* we have no desire to set the value.
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* Sixth Argument: The length of the buffer containing new information (argument five). In this case
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* argument five was null since we didn't want to set the system value. Thus, the size of the buffer
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* is zero or NULL.
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* Return Value: a return value indicating success or failure. Actually, sysctl will either return
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* zero on no error and -1 on error. The errno UNIX variable will be set on error.
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*/
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error = sysctl(mib, 3, NULL, &sizeOfBufferRequired, NULL, NULL);
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/* If an error occurred then return the accociated error. The error itself actually is stored in the UNIX
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* errno variable. We can access the errno value using the errno global variable. We will return the
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* errno value as the sysctlError return value from this function.
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*/
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if (error != 0)
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{
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if (SysctlError != NULL)
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{
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*SysctlError = errno; //we only set this variable if the pre-allocated variable is given
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}
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return(kErrorGettingSizeOfBufferRequired);
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}
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/* Now we successful obtained the size of the buffer required for the sysctl call. This is stored in the
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* SizeOfBufferRequired variable. We will malloc a buffer of that size to hold the sysctl result.
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*/
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BSDProcessInformationStructure = (struct kinfo_proc*) malloc(sizeOfBufferRequired);
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if (BSDProcessInformationStructure == NULL)
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{
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if (SysctlError != NULL)
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{
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*SysctlError = ENOMEM; //we only set this variable if the pre-allocated variable is given
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}
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return(kUnableToAllocateMemoryForBuffer); //unrecoverable error (no memory available) so give up
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}
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/* Now we have the buffer of the correct size to hold the result we can now call sysctl
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* and get the process information.
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*
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* First Argument: The MIB for gathering information on running BSD processes. The MIB is really
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* just an array of integers. Each integer is a constant representing what information to
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* gather from the system. Check out the man page to know what constants sysctl will work with.
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* Second Argument: The number of constants in the MIB (array of integers). In this case there are three.
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* Third Argument: The output buffer where the return value from sysctl will be stored. This is the buffer
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* which we allocated specifically for this purpose.
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* Forth Argument: The size of the output buffer (argument three). In this case its the size of the
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* buffer we already allocated.
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* Fifth Argument: The buffer containing the value to set the system value to. In this case we don't
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* want to set any system information we only want to gather it. Thus, we pass null as the buffer
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* so sysctl knows that we have no desire to set the value.
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* Sixth Argument: The length of the buffer containing new information (argument five). In this case
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* argument five was null since we didn't want to set the system value. Thus, the size of the buffer
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* is zero or NULL.
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* Return Value: a return value indicating success or failure. Actually, sysctl will either return
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* zero on no error and -1 on error. The errno UNIX variable will be set on error.
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*/
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error = sysctl(mib, 3, BSDProcessInformationStructure, &sizeOfBufferRequired, NULL, NULL);
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//Here we successfully got the process information. Thus set the variable to end this sysctl calling loop
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if (error == 0)
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{
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SuccessfullyGotProcessInformation = TRUE;
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}
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else
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{
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/* failed getting process information we will try again next time around the loop. Note this is caused
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* by the fact the process list changed between getting the size of the buffer and actually filling
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* the buffer (something which will happen from time to time since the process list is dynamic).
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* Anyways, the attempted sysctl call failed. We will now begin again by freeing up the allocated
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* buffer and starting again at the beginning of the loop.
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*/
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free(BSDProcessInformationStructure);
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}
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}//end while loop
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// --- Going through process list looking for processes with matching names --- //
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/* Now that we have the BSD structure describing the running processes we will parse it for the desired
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* process name. First we will the number of running processes. We can determine
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* the number of processes running because there is a kinfo_proc structure for each process.
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*/
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NumberOfRunningProcesses = sizeOfBufferRequired / sizeof(struct kinfo_proc);
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/* Now we will go through each process description checking to see if the process name matches that
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* passed to us. The BSDProcessInformationStructure has an array of kinfo_procs. Each kinfo_proc has
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* an extern_proc accociated with it in the kp_proc attribute. Each extern_proc (kp_proc) has the process name
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* of the process accociated with it in the p_comm attribute and the PID of that process in the p_pid attibute.
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* We test the process name by compairing the process name passed to us with the value in the p_comm value.
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* Note we limit the compairison to MAXCOMLEN which is the maximum length of a BSD process name which is used
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* by the system.
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*/
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for (Counter = 0 ; Counter < NumberOfRunningProcesses ; Counter++)
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{
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//Getting PID of process we are examining
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CurrentExaminedProcessPID = BSDProcessInformationStructure[Counter].kp_proc.p_pid;
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//Getting name of process we are examining
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CurrentExaminedProcessName = BSDProcessInformationStructure[Counter].kp_proc.p_comm;
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if ((CurrentExaminedProcessPID > 0) //Valid PID
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&& ((strncmp(CurrentExaminedProcessName, ProcessName, MAXCOMLEN) == 0))) //name matches
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{
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// --- Got a match add it to the array if possible --- //
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if ((*NumberOfMatchesFound + 1) > NumberOfPossiblePIDsInArray)
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{
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//if we overran the array buffer passed we release the allocated buffer give an error.
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free(BSDProcessInformationStructure);
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return(kPIDBufferOverrunError);
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}
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//adding the value to the array.
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ArrayOfReturnedPIDs[*NumberOfMatchesFound] = CurrentExaminedProcessPID;
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//incrementing our number of matches found.
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*NumberOfMatchesFound = *NumberOfMatchesFound + 1;
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}
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}//end looking through process list
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free(BSDProcessInformationStructure); //done with allocated buffer so release.
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if (*NumberOfMatchesFound == 0)
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{
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//didn't find any matches return error.
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return(kCouldNotFindRequestedProcess);
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}
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else
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{
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//found matches return success.
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return(kSuccess);
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}
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}
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/*****************************************************
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* GetPIDForProcessName
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*****************************************************
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* Purpose: A convience call for GetAllPIDsForProcessName().
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* This function looks up a process PID given a BSD process
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* name.
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*
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* Parameters:
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* ProcessName A constant C-string. On calling
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* GetPIDForProcessName this variable holds the BSD process name
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* used to do the process lookup. Note that the process name you need
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* to pass is the name of the BSD executable process. If trying
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* to find the PID of an regular OSX application you will need to pass the
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* name of the actual BSD executable inside an application bundle (rather
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* than the bundle name itself). In any case as a user you can find the
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* BSD process name of any process (including OSX applications) by
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* typing the command "ps -axcocommand,pid" in terminal.
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*
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* *Function Result* A integer return value.
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* See result codes listed below.
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* Result Codes:
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* >0 Success. The value returned is the PID of the
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* matching process.
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* -1 Error getting PID for requested process. This error can
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* be caused by several things. One is if no such process exists.
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* Another is if more than one process has the given name. The
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* thing to do here is to call GetAllPIDsForProcessName()
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* for complete error code or to get PIDs if there are multiple
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* processes with that name.
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*****************************************************/
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int GetPIDForProcessName(const char* ProcessName)
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{
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pid_t PIDArray[1] = {0};
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int Error = 0;
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int NumberOfMatches = 0;
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/* Here we are calling the function GetAllPIDsForProcessName which wil give us the PIDs
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* of the process name we pass. Of course here we are hoping for a single PID return.
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* First Argument: The BSD process name of the process we want to lookup. In this case the
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* the process name passed to us.
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* Second Argument: A preallocated array of pid_t. This is where the PIDs of matching processes
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* will be placed on return. We pass the array we just allocated which is length one.
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* Third Argument: The number of pid_t entries located in the array of pid_t (argument 2). In this
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* case our array has one pid_t entry so pass one.
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* Forth Argument: On return this will hold the number of PIDs placed into the
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* pid_t array (array passed in argument 2).
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* Fifth Argument: Passing NULL to ignore this argument.
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* Return Value: An error indicating success (zero result) or failure (non-zero).
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*
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*/
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Error = GetAllPIDsForProcessName(ProcessName, PIDArray, 1, &NumberOfMatches, NULL);
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if ((Error == 0) && (NumberOfMatches == 1))//success!
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{
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return((int) PIDArray[0]); //return the one PID we found.
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}
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else
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{
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return(-1);
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}
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}
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