GetBSDProcessList.h

#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/sysctl.h>

typedef struct kinfo_proc kinfo_proc;
const int max_processes = 1024;

/*
 * From https://blog.csdn.net/shark0001/article/details/5943376
 */

/*
static int GetBSDProcessList(kinfo_proc **procList, size_t *procCount);

int main (int argc, const char * argv[]) {
	// insert code here...

	kinfo_proc *        results;// = malloc(sizeof(kinfo_proc*)*max_processes);
	size_t procCount=0;
	GetBSDProcessList(&results, &procCount);
	kinfo_proc* current_process = results;
	for (int i=0; i<procCount && i<max_processes; i++)
	{
		//kinfo_proc* process_info = results[i];
		if(current_process->kp_proc.p_pid){
			printf("process id:%d", current_process->kp_proc.p_pid);
		}
		if (current_process->kp_proc.p_comm) {
			printf("/tname:%s", current_process->kp_proc.p_comm);
		}
		printf("/n");
		current_process += 1;
	}
	free(results);
	results = NULL;
	return 0;
}
*/


static int GetBSDProcessList(kinfo_proc **procList, size_t *procCount)
// Returns a list of all BSD processes on the system.  This routine
// allocates the list and puts it in *procList and a count of the
// number of entries in *procCount.  You are responsible for freeing
// this list (use "free" from System framework).
// On success, the function returns 0.
// On error, the function returns a BSD errno value.
{
	int                 err;
	kinfo_proc *        result;
	bool                done;
	static const int    name[] = { CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0 };
	// Declaring name as const requires us to cast it when passing it to
	// sysctl because the prototype doesn't include the const modifier.
	size_t              length;
	assert( procList != NULL);
	assert(*procList == NULL);
	assert(procCount != NULL);
	*procCount = 0;
	// We start by calling sysctl with result == NULL and length == 0.
	// That will succeed, and set length to the appropriate length.
	// We then allocate a buffer of that size and call sysctl again
	// with that buffer.  If that succeeds, we're done.  If that fails
	// with ENOMEM, we have to throw away our buffer and loop.  Note
	// that the loop causes use to call sysctl with NULL again; this
	// is necessary because the ENOMEM failure case sets length to
	// the amount of data returned, not the amount of data that
	// could have been returned.
	result = NULL;
	done = false;
	do {
		assert(result == NULL);
		// Call sysctl with a NULL buffer.
		length = 0;
		err = sysctl( (int *) name, (sizeof(name) / sizeof(*name)) - 1,
      NULL, &length,
      NULL, 0);
		if (err == -1) {
			err = errno;
		}
		// Allocate an appropriately sized buffer based on the results
		// from the previous call.
		if (err == 0) {
			result = (kinfo_proc *)malloc(length);
			if (result == NULL) {
				err = ENOMEM;
			}
		}
		// Call sysctl again with the new buffer.  If we get an ENOMEM
		// error, toss away our buffer and start again.
		if (err == 0) {
			err = sysctl( (int *) name, (sizeof(name) / sizeof(*name)) - 1,
        result, &length,
        NULL, 0);
			if (err == -1) {
				err = errno;
			}
			if (err == 0) {
				done = true;
			} else if (err == ENOMEM) {
				assert(result != NULL);
				free(result);
				result = NULL;
				err = 0;
			}
		}
	} while (err == 0 && ! done);
	// Clean up and establish post conditions.
	if (err != 0 && result != NULL) {
		free(result);
		result = NULL;
	}
	*procList = result;
	if (err == 0) {
		*procCount = length / sizeof(kinfo_proc);
	}
	assert( (err == 0) == (*procList != NULL) );
	return err;
}