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/*
* mmaptest.c
*
* Test some simple cases of mmap()
*/
#include <sys/mman.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <stdint.h>
#include <fcntl.h>
static void make_test_file(int fd)
{
unsigned long v;
FILE *f = fdopen(fd, "wb");
for (v = 0; v < 262144; v += sizeof(v))
_fwrite(&v, sizeof(v), f);
}
int main(int argc, char *argv[])
{
void *foo;
char *test_file = (argc > 1) ? argv[1] : "/tmp/mmaptest.tmp";
int rv, fd;
/* Important case, this is how we get memory for malloc() */
errno = 0;
foo = mmap(NULL, 65536, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
printf("mmap() returned %p, errno = %d\n", foo, errno);
if (foo == MAP_FAILED)
return 1;
rv = munmap(foo, 65536);
printf("munmap() returned %d, errno = %d\n", rv, errno);
if (rv)
return 1;
/* Create test file */
fd = open(test_file, O_RDWR | O_CREAT | O_TRUNC, 0666);
if (fd < 0) {
perror(test_file);
return 1;
}
make_test_file(fd);
/* Map test file */
foo = mmap(NULL, 65536, PROT_READ, MAP_SHARED, fd, 131072);
printf("mmap() returned %p, errno = %d\n", foo, errno);
if (foo == MAP_FAILED)
return 1;
if (*(unsigned long *)foo != 131072) {
printf("mmap() with offset returned the wrong offset %ld!\n",
*(unsigned long *)foo);
return 1;
}
if (munmap(foo, 65536)) {
printf("munmap() returned nonzero, errno = %d\n", errno);
return 1;
}
close(fd);
unlink(test_file);
return 0;
}
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