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From: Joe Greco <jgreco@solaria.sol.net>
Message-Id: <199612111636.KAA03706@solaria.sol.net>
Subject: mlocking an mmap'ped region?
To: current@freebsd.org, dyson@freebsd.org
Date: Wed, 11 Dec 96 10:35:59 CST
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The following does not seem to work on a 2.2-CURRENT box (built yesterday).
It does seem to work on SunOS.

Is it just too early to be doing programming or is there really something
preventing me from doing this?

Thanks,

... JG


#include	<stdio.h>
#include	<unistd.h>
#include	<fcntl.h>
#include	<string.h>
#include	<sys/types.h>
#include	<sys/mman.h>
#include	<sys/stat.h>

/*
 * mlock-files - read a list of files on stdin, mmap() them, mlock() them,
 * and then sleep forever.
 */





int mapper(fd)
int fd;
{
	struct stat sb;
        size_t size;
        caddr_t map;

	if (fstat(fd, &sb) < 0) {
                perror("fstat");
                close(fd);
                return(-1);
	}
	size = (size_t)sb.st_size;

        if ((int)(map = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0)) == -1) {
                perror("mmap");
                close(fd);
                return(-1);
        }
	if (mlock(map, size) < 0) {
                perror("mlock");
		fprintf(stderr, "map = %08x eof=%d\n", map, size);
                close(fd);
                return(-1);
        } else {
		fprintf(stderr, "allocated map = %08x eof=%d\n", map, size);
	}
        close(fd);
        return(0);
}





int main(int argc, char *argv[])
{
	int fd;
	char buffer[8192];

	if (argc != 1) {
		fprintf(stderr, "usage: mlock-files\n");
		exit(1);
	}
	while (! feof(stdin)) {
		fgets(buffer, sizeof(buffer), stdin);
		if (strchr(buffer, '\n')) {
			*strchr(buffer, '\n') = '\0';
		}
		if (! feof(stdin)) {
			if ((fd = open(buffer, O_RDONLY, 0755)) < 0) {
				perror(buffer);
			} else {
				mapper(fd);
			}
		}
	}
	sleep(99999999);
}
-- 
... Joe

-------------------------------------------------------------------------------
Joe Greco - Systems Administrator			      jgreco@ns.sol.net
Solaria Public Access UNIX - Milwaukee, WI			   414/342-4847