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[[!tag open_issue_glibc]]
# IRC, freenode, #hurd, 2011-12-14
<pinotree> hm, interesting mmap bug
<youpi> ?
<pinotree> youpi: http://paste.debian.net/149252/
#include <sys/types.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
void die(int x, const char *s)
{
perror(s);
exit(x);
}
static const char s_file[] = "foo-mmaptest";
int main()
{
int fd;
void *p;
fd = creat(s_file, 0777);
if (fd < 0) die(1, "creat");
errno = 0;
p = mmap(NULL, 1, PROT_READ, MAP_SHARED, fd, 0);
printf("> %p vs %p, %d (%s)\n", p, MAP_FAILED, errno, strerror(errno));
unlink(s_file);
return (p != MAP_FAILED);
}
<pinotree> on linux it returns 0 and fails with EACCESS (as it seems it
should, by reading the mmap posix docs), on hurd it returns 1 and the
mmap succeeds
<pinotree> (taken from llvm's configure)
<youpi> why should it? file size extension ?
<pinotree> creat creates a o_wronly file, while the mmap specifies only
read protection
<youpi> oh, craet is always wo
<youpi> I didn't know that
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