Redline/source/GetPID.c
maride 02061d74c2 Original 1.0.5 code
(as received from Jonas Echterhoff)
2016-04-02 14:43:55 +02:00

403 lines
21 KiB
C
Executable File

/*
File: GetPID.c
Description: This file provides a simple API to do process PID lookup based on process name.
Author: Chad Jones
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*/
#include "GetPID.h"
#include <errno.h>
#include <string.h>
#include <sys/sysctl.h>
/*****************************************************
* GetAllPIDsForProcessName
*****************************************************
* Purpose: This functions purpose is to lookup a BSD
* process PID given the BSD process name. This function may
* potentially return multiple PIDs for a given BSD process name
* since several processes can have the same BSD process name.
*
* Parameters:
* ProcessName A constant C-string. On calling
* GetAllPIDsForProcessName this variable holds the BSD process name
* used to do the process lookup. Note that the process name you need
* to pass is the name of the BSD executable process. If trying
* to find the PID of an regular OSX application you will need to pass the
* name of the actual BSD executable inside an application bundle (rather
* than the bundle name itself). In any case as a user you can find the
* BSD process name of any process (including OSX applications) by
* typing the command "ps -axcocommand,pid" in terminal.
*
* ArrayOfReturnedPIDs A pointer to a pre-allocated array of pid_t.
* On calling GetAllPIDsForProcessName this variable must be a pointer to a
* pre-allocated array of pid_t whos length (in number of pid_t entries) is defined
* in ArrayOfPIDsLength. On successful return from GetAllPIDsForProcessName
* this array will hold the PIDs of all processes which have a matching process
* name to that specified in the ProcessName input variable. The number of actual
* PIDs entered in the array starting at index zero will be the value returned
* in NumberOfMatchesFound. On failed return if the error is a buffer overflow
* error then the buffer will be filled to the max with PIDs which matched.
* Otherwise on failed return the state of the array will be undefined. Note
* the returned PID array is not sorted and is listed in order of process encountered.
*
* NumberOfPossiblePIDsInArray A unsigned integer. On calling
* GetAllPIDsForProcessName this variable will hold the number of
* pre-allocated PID entries which are in the ArrayOfReturnedPIDs for this functions
* use. Note this value must have a value greater than zero.
*
* NumberOfMatchesFound An unsigned integer. On calling GetAllPIDsForProcessName
* this variable will point to a pre-allocated unsigned integer. On return from
* GetAllPIDsForProcessName this variable will contain the number of PIDs contained in the
* ArrayOfReturnedPIDs. On failed return the value of the variable will be undefined.
*
* SysctlError A pointer to a pre-allocated integer. On failed return, this
* variable represents the error returned from the sysctl command. On function
* success this variable will have a value specified by the sysctl based on the
* error that occurred. On success the variable will have the value zero.
* Note this variable can also be NULL in which case the variable is ignored.
*
* *Function Result* A integer return value.
* See result codes listed below.
* Result Codes:
* 0 Success. A set of process PIDs were found and are located in
* ArrayOfReturnedPIDs array.
* -1 Could not find a process with a matching process name
* (i.e. process not found).
* -2 Invalid arguments passed.
* -3 Unable to get the size of sysctl buffer required
* (consult SysctlError return value for more information)
* -4 Unable to allocate memory to store BSD process information
* (consult SysctlError return value for more information)
* -5 The array passed to hold the returned PIDs is not large enough
* to hold all PIDs of process with matching names.
*
*****************************************************/
int GetAllPIDsForProcessName(const char* ProcessName,
pid_t ArrayOfReturnedPIDs[],
const unsigned int NumberOfPossiblePIDsInArray,
unsigned int* NumberOfMatchesFound,
int* SysctlError)
{
// --- Defining local variables for this function and initializing all to zero --- //
int mib[6] = {0,0,0,0,0,0}; //used for sysctl call.
int SuccessfullyGotProcessInformation;
size_t sizeOfBufferRequired = 0; //set to zero to start with.
int error = 0;
long NumberOfRunningProcesses = 0;
unsigned int Counter = 0;
struct kinfo_proc* BSDProcessInformationStructure = NULL;
pid_t CurrentExaminedProcessPID = 0;
char* CurrentExaminedProcessName = NULL;
// --- Checking input arguments for validity --- //
if (ProcessName == NULL) //need valid process name
{
return(kInvalidArgumentsError);
}
if (ArrayOfReturnedPIDs == NULL) //need an actual array
{
return(kInvalidArgumentsError);
}
if (NumberOfPossiblePIDsInArray <= 0)
{
//length of the array must be larger than zero.
return(kInvalidArgumentsError);
}
if (NumberOfMatchesFound == NULL) //need an integer for return.
{
return(kInvalidArgumentsError);
}
//--- Setting return values to known values --- //
//initalizing PID array so all values are zero
memset(ArrayOfReturnedPIDs, 0, NumberOfPossiblePIDsInArray * sizeof(pid_t));
*NumberOfMatchesFound = 0; //no matches found yet
if (SysctlError != NULL) //only set sysctlError if it is present
{
*SysctlError = 0;
}
//--- Getting list of process information for all processes --- //
/* Setting up the mib (Management Information Base) which is an array of integers where each
* integer specifies how the data will be gathered. Here we are setting the MIB
* block to lookup the information on all the BSD processes on the system. Also note that
* every regular application has a recognized BSD process accociated with it. We pass
* CTL_KERN, KERN_PROC, KERN_PROC_ALL to sysctl as the MIB to get back a BSD structure with
* all BSD process information for all processes in it (including BSD process names)
*/
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_ALL;
/* Here we have a loop set up where we keep calling sysctl until we finally get an unrecoverable error
* (and we return) or we finally get a succesful result. Note with how dynamic the process list can
* be you can expect to have a failure here and there since the process list can change between
* getting the size of buffer required and the actually filling that buffer.
*/
SuccessfullyGotProcessInformation = FALSE;
while (SuccessfullyGotProcessInformation == FALSE)
{
/* Now that we have the MIB for looking up process information we will pass it to sysctl to get the
* information we want on BSD processes. However, before we do this we must know the size of the buffer to
* allocate to accomidate the return value. We can get the size of the data to allocate also using the
* sysctl command. In this case we call sysctl with the proper arguments but specify no return buffer
* specified (null buffer). This is a special case which causes sysctl to return the size of buffer required.
*
* First Argument: The MIB which is really just an array of integers. Each integer is a constant
* representing what information to gather from the system. Check out the man page to know what
* constants sysctl will work with. Here of course we pass our MIB block which was passed to us.
* Second Argument: The number of constants in the MIB (array of integers). In this case there are three.
* Third Argument: The output buffer where the return value from sysctl will be stored. In this case
* we don't want anything return yet since we don't yet know the size of buffer needed. Thus we will
* pass null for the buffer to begin with.
* Forth Argument: The size of the output buffer required. Since the buffer itself is null we can just
* get the buffer size needed back from this call.
* Fifth Argument: The new value we want the system data to have. Here we don't want to set any system
* information we only want to gather it. Thus, we pass null as the buffer so sysctl knows that
* we have no desire to set the value.
* Sixth Argument: The length of the buffer containing new information (argument five). In this case
* argument five was null since we didn't want to set the system value. Thus, the size of the buffer
* is zero or NULL.
* Return Value: a return value indicating success or failure. Actually, sysctl will either return
* zero on no error and -1 on error. The errno UNIX variable will be set on error.
*/
error = sysctl(mib, 3, NULL, &sizeOfBufferRequired, NULL, NULL);
/* If an error occurred then return the accociated error. The error itself actually is stored in the UNIX
* errno variable. We can access the errno value using the errno global variable. We will return the
* errno value as the sysctlError return value from this function.
*/
if (error != 0)
{
if (SysctlError != NULL)
{
*SysctlError = errno; //we only set this variable if the pre-allocated variable is given
}
return(kErrorGettingSizeOfBufferRequired);
}
/* Now we successful obtained the size of the buffer required for the sysctl call. This is stored in the
* SizeOfBufferRequired variable. We will malloc a buffer of that size to hold the sysctl result.
*/
BSDProcessInformationStructure = (struct kinfo_proc*) malloc(sizeOfBufferRequired);
if (BSDProcessInformationStructure == NULL)
{
if (SysctlError != NULL)
{
*SysctlError = ENOMEM; //we only set this variable if the pre-allocated variable is given
}
return(kUnableToAllocateMemoryForBuffer); //unrecoverable error (no memory available) so give up
}
/* Now we have the buffer of the correct size to hold the result we can now call sysctl
* and get the process information.
*
* First Argument: The MIB for gathering information on running BSD processes. The MIB is really
* just an array of integers. Each integer is a constant representing what information to
* gather from the system. Check out the man page to know what constants sysctl will work with.
* Second Argument: The number of constants in the MIB (array of integers). In this case there are three.
* Third Argument: The output buffer where the return value from sysctl will be stored. This is the buffer
* which we allocated specifically for this purpose.
* Forth Argument: The size of the output buffer (argument three). In this case its the size of the
* buffer we already allocated.
* Fifth Argument: The buffer containing the value to set the system value to. In this case we don't
* want to set any system information we only want to gather it. Thus, we pass null as the buffer
* so sysctl knows that we have no desire to set the value.
* Sixth Argument: The length of the buffer containing new information (argument five). In this case
* argument five was null since we didn't want to set the system value. Thus, the size of the buffer
* is zero or NULL.
* Return Value: a return value indicating success or failure. Actually, sysctl will either return
* zero on no error and -1 on error. The errno UNIX variable will be set on error.
*/
error = sysctl(mib, 3, BSDProcessInformationStructure, &sizeOfBufferRequired, NULL, NULL);
//Here we successfully got the process information. Thus set the variable to end this sysctl calling loop
if (error == 0)
{
SuccessfullyGotProcessInformation = TRUE;
}
else
{
/* failed getting process information we will try again next time around the loop. Note this is caused
* by the fact the process list changed between getting the size of the buffer and actually filling
* the buffer (something which will happen from time to time since the process list is dynamic).
* Anyways, the attempted sysctl call failed. We will now begin again by freeing up the allocated
* buffer and starting again at the beginning of the loop.
*/
free(BSDProcessInformationStructure);
}
}//end while loop
// --- Going through process list looking for processes with matching names --- //
/* Now that we have the BSD structure describing the running processes we will parse it for the desired
* process name. First we will the number of running processes. We can determine
* the number of processes running because there is a kinfo_proc structure for each process.
*/
NumberOfRunningProcesses = sizeOfBufferRequired / sizeof(struct kinfo_proc);
/* Now we will go through each process description checking to see if the process name matches that
* passed to us. The BSDProcessInformationStructure has an array of kinfo_procs. Each kinfo_proc has
* an extern_proc accociated with it in the kp_proc attribute. Each extern_proc (kp_proc) has the process name
* of the process accociated with it in the p_comm attribute and the PID of that process in the p_pid attibute.
* We test the process name by compairing the process name passed to us with the value in the p_comm value.
* Note we limit the compairison to MAXCOMLEN which is the maximum length of a BSD process name which is used
* by the system.
*/
for (Counter = 0 ; Counter < NumberOfRunningProcesses ; Counter++)
{
//Getting PID of process we are examining
CurrentExaminedProcessPID = BSDProcessInformationStructure[Counter].kp_proc.p_pid;
//Getting name of process we are examining
CurrentExaminedProcessName = BSDProcessInformationStructure[Counter].kp_proc.p_comm;
if ((CurrentExaminedProcessPID > 0) //Valid PID
&& ((strncmp(CurrentExaminedProcessName, ProcessName, MAXCOMLEN) == 0))) //name matches
{
// --- Got a match add it to the array if possible --- //
if ((*NumberOfMatchesFound + 1) > NumberOfPossiblePIDsInArray)
{
//if we overran the array buffer passed we release the allocated buffer give an error.
free(BSDProcessInformationStructure);
return(kPIDBufferOverrunError);
}
//adding the value to the array.
ArrayOfReturnedPIDs[*NumberOfMatchesFound] = CurrentExaminedProcessPID;
//incrementing our number of matches found.
*NumberOfMatchesFound = *NumberOfMatchesFound + 1;
}
}//end looking through process list
free(BSDProcessInformationStructure); //done with allocated buffer so release.
if (*NumberOfMatchesFound == 0)
{
//didn't find any matches return error.
return(kCouldNotFindRequestedProcess);
}
else
{
//found matches return success.
return(kSuccess);
}
}
/*****************************************************
* GetPIDForProcessName
*****************************************************
* Purpose: A convience call for GetAllPIDsForProcessName().
* This function looks up a process PID given a BSD process
* name.
*
* Parameters:
* ProcessName A constant C-string. On calling
* GetPIDForProcessName this variable holds the BSD process name
* used to do the process lookup. Note that the process name you need
* to pass is the name of the BSD executable process. If trying
* to find the PID of an regular OSX application you will need to pass the
* name of the actual BSD executable inside an application bundle (rather
* than the bundle name itself). In any case as a user you can find the
* BSD process name of any process (including OSX applications) by
* typing the command "ps -axcocommand,pid" in terminal.
*
* *Function Result* A integer return value.
* See result codes listed below.
* Result Codes:
* >0 Success. The value returned is the PID of the
* matching process.
* -1 Error getting PID for requested process. This error can
* be caused by several things. One is if no such process exists.
* Another is if more than one process has the given name. The
* thing to do here is to call GetAllPIDsForProcessName()
* for complete error code or to get PIDs if there are multiple
* processes with that name.
*****************************************************/
int GetPIDForProcessName(const char* ProcessName)
{
pid_t PIDArray[1] = {0};
int Error = 0;
int NumberOfMatches = 0;
/* Here we are calling the function GetAllPIDsForProcessName which wil give us the PIDs
* of the process name we pass. Of course here we are hoping for a single PID return.
* First Argument: The BSD process name of the process we want to lookup. In this case the
* the process name passed to us.
* Second Argument: A preallocated array of pid_t. This is where the PIDs of matching processes
* will be placed on return. We pass the array we just allocated which is length one.
* Third Argument: The number of pid_t entries located in the array of pid_t (argument 2). In this
* case our array has one pid_t entry so pass one.
* Forth Argument: On return this will hold the number of PIDs placed into the
* pid_t array (array passed in argument 2).
* Fifth Argument: Passing NULL to ignore this argument.
* Return Value: An error indicating success (zero result) or failure (non-zero).
*
*/
Error = GetAllPIDsForProcessName(ProcessName, PIDArray, 1, &NumberOfMatches, NULL);
if ((Error == 0) && (NumberOfMatches == 1))//success!
{
return((int) PIDArray[0]); //return the one PID we found.
}
else
{
return(-1);
}
}