Paste: sysctl works in c

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

typedef struct kinfo_proc kinfo_proc;

static void hex_dump(void *data, int size);


static void hex_dump(void *data, int size)
{
    /* dumps size bytes of *data to stdout. Looks like:
     * [0000] 75 6E 6B 6E 6F 77 6E 20
     *                  30 FF 00 00 00 00 39 00 unknown 0.....9.
     * (in a single line of course)
     */

    unsigned char *p = data;
    unsigned char c;
    int n;
    char bytestr[4] = {0};
    char addrstr[10] = {0};
    char hexstr[ 16*3 + 5] = {0};
    char charstr[16*1 + 5] = {0};
    for(n=1;n<=size;n++) {
        if (n%16 == 1) {
            /* store address for this line */
            snprintf(addrstr, sizeof(addrstr), "%.4x",
               ((unsigned int)p-(unsigned int)data) );
        }
            
        c = *p;
        if (isalnum(c) == 0) {
            c = '.';
        }

        /* store hex str (for left side) */
        snprintf(bytestr, sizeof(bytestr), "%02X ", *p);
        strncat(hexstr, bytestr, sizeof(hexstr)-strlen(hexstr)-1);

        /* store char str (for right side) */
        snprintf(bytestr, sizeof(bytestr), "%c", c);
        strncat(charstr, bytestr, sizeof(charstr)-strlen(charstr)-1);

        if(n%16 == 0) { 
            /* line completed */
            printf("[%4.4s]   %-50.50s  %s\n", addrstr, hexstr, charstr);
            hexstr[0] = 0;
            charstr[0] = 0;
        } else if(n%8 == 0) {
            /* half line: add whitespaces */
            strncat(hexstr, "  ", sizeof(hexstr)-strlen(hexstr)-1);
            strncat(charstr, " ", sizeof(charstr)-strlen(charstr)-1);
        }
        p++; /* next byte */
    }

    if (strlen(hexstr) > 0) {
        /* print rest of buffer if not empty */
        printf("[%4.4s]   %-50.50s  %s\n", addrstr, hexstr, charstr);
    }
}

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 = 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;
}

static int GetBSDProcessList2(void **procList, size_t *procCount)
{
    int                 err;
    kinfo_proc *        result;
    bool                done;
    static const int    name[] = { CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0 };
    size_t              length;

    *procCount = 0;

    result = NULL;
    done = false;
    do {

        length = 0;
        err = sysctl( (int *) name, (sizeof(name) / sizeof(*name)) - 1,
                      NULL, &length,
                      NULL, 0);
        if (err == -1) {
            err = errno;
        }

        if (err == 0) {
            result = malloc(length);
            if (result == NULL) {
                err = ENOMEM;
            }
        }

        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);

    if (err != 0 && result != NULL) {
        free(result);
        result = NULL;
    }
    *procList = result;
    if (err == 0) {
        *procCount = length;
    }

    return err;
}

int main()
{
    kinfo_proc *list;
    size_t count = 0;
    void *list2;
    size_t count2 = 0;
	int i;

    list = (kinfo_proc *)malloc(sizeof(kinfo_proc));

	for(i=0; i < 100; i++)
	{
    	int err = GetBSDProcessList2(&list2, &count2);

		if(err == EFAULT)
			printf("efault!!!!!!!!\n");
		//else if(err == 0)
			//hex_dump(list2, count2);
	}

	
	//printf("sizeof extern_proc = %d\n", (int)sizeof(struct extern_proc));
	//printf("sizeof _pcred = %d\n", (int)sizeof(struct _pcred));
	//printf("sizeof _ucred = %d\n", (int)sizeof(struct _ucred));
	//printf("sizeof eproc = %d\n", (int)sizeof(struct eproc));
	printf("sizeof kinfo_proc = %d\n", (int)sizeof(struct kinfo_proc));
	return 0;
}