I don't see a check of the return value of the open() call.  Could it be -1 (invalid)?

On Mon, 3 Jul 2006 17:52:08 -0400 (EDT)
Kristaps Johnson <kristaps@gradient-enterprises.com> wrote:

> 
> Hello all!
> 
> I wonder if somebody can help me with a strange error I receive under 
> systrace on NetBSD.  I've included a sample programme below with 
> error-checking stripped in non-applicable areas.  The "sys/systrace.h" 
> header file is current from CVS. Overall system NetBSD 3.0, GENERIC.  I'm 
> trying to port sysjail (sysjail.bsd.lv) to NetBSD and this is keeping me 
> hard up.  Suggestions?
> 
> Note that this works fine with the OpenBSD systrace (3.9), which adds to 
> the mystification.
> 
> The "strange error" is EINVAL: Invalid argument.
> 
> The below is run as "./a.out 5123", where 5123 is a process doing things (I 
> have a script looping echo -n '.').
> 
> 
> #include <sys/ioctl.h>
> #include <sys/param.h>
> #include <sys/types.h>
> #include <sys/wait.h>
> #ifdef __NetBSD__
> # include <sys/systrace.h>
> #elif __OpenBSD__
> # include <dev/systrace.h>
> #endif
> 
> #include <err.h>
> #include <errno.h>
> #include <fcntl.h>
> #include <poll.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <unistd.h>
> 
> int
> main(int argc, const char *argv[])
> {
>          struct str_message msg;
>          struct systrace_policy pol;
>          struct pollfd pfd;
>          int fd, ofd;
>          pid_t cpid;
> 
>          cpid = atoi(argv[1]);
> 
>          ofd = open("/dev/systrace", O_RDWR | O_NONBLOCK, 0);
> #ifdef __OpenBSD__
>          ioctl(ofd, STRIOCCLONE, &fd);
>          close(ofd);
> #elif __NetBSD__
>          fd = ofd;
> #endif
>          fcntl(fd, F_SETFD, FD_CLOEXEC);
> 
>          memset(&pol, 0, sizeof(pol));
>          pol.strp_op = SYSTR_POLICY_NEW;
>          pol.strp_num = -1;
>          pol.strp_maxents = 512;
> 
>          ioctl(fd, STRIOCPOLICY, &pol);
>          ioctl(fd, STRIOCATTACH, &cpid);
> 
>          memset(&pfd, 0, sizeof(pfd));
>          pfd.fd = fd;
>          pfd.events = POLLIN;
> 
>          poll(&pfd, 1, -1);
> 
>          /* RETURNS AN ERROR:
>           * read: /dev/systrace: Invalid argument */
>          if (read(fd, &msg, sizeof(struct str_message))
>                          != sizeof(struct str_message)) {
>                  err(1, "read: /dev/systrace");
>          }
> 
>          return(0);
> }
> 
>