libseccomp/doc/man/man3/seccomp_export_bpf.3

   1 .TH "seccomp_export_bpf" 3 "25 July 2012" "paul@paul-moore.com" "libseccomp Documentation"
   2 .\" //////////////////////////////////////////////////////////////////////////
   3 .SH NAME
   4 .\" //////////////////////////////////////////////////////////////////////////
   5 seccomp_export_bpf, seccomp_export_pfc \- Export the seccomp filter
   6 .\" //////////////////////////////////////////////////////////////////////////
   7 .SH SYNOPSIS
   8 .\" //////////////////////////////////////////////////////////////////////////
   9 .nf
  10 .B #include <seccomp.h>
  11 .sp
  12 .B typedef void * scmp_filter_ctx;
  13 .sp
  14 .BI "int seccomp_export_bpf(const scmp_filter_ctx " ctx ", int " fd ");"
  15 .BI "int seccomp_export_pfc(const scmp_filter_ctx " ctx ", int " fd ");"
  16 .sp
  17 Link with \fI\-lseccomp\fP.
  18 .fi
  19 .\" //////////////////////////////////////////////////////////////////////////
  20 .SH DESCRIPTION
  21 .\" //////////////////////////////////////////////////////////////////////////
  22 .P
  23 The
  24 .BR seccomp_export_bpf ()
  25 and
  26 .BR seccomp_export_pfc ()
  27 functions generate and output the current seccomp filter in either BPF (Berkley
  28 Packet Filter) or PFC (Pseudo Filter Code).  The output of
  29 .BR seccomp_export_bpf ()
  30 is suitable for loading into the kernel, while the output of
  31 .BR seccomp_export_pfc ()
  32 is human readable and is intended primarily as a debugging tool for developers
  33 using libseccomp.  Both functions write the filter to the
  34 .I fd
  35 file descriptor.
  36 .P
  37 The filter context
  38 .I ctx
  39 is the value returned by the call to
  40 .BR seccomp_init (3).
  41 .P
  42 While the two output formats are guaranteed to be functionally equivalent for
  43 the given seccomp filter configuration, the filter instructions, and their
  44 ordering, are not guaranteed to be the same in both the BPF and PFC formats.
  45 .\" //////////////////////////////////////////////////////////////////////////
  46 .SH RETURN VALUE
  47 .\" //////////////////////////////////////////////////////////////////////////
  48 Returns zero on success, negative errno values on failure.
  49 .\" //////////////////////////////////////////////////////////////////////////
  50 .SH EXAMPLES
  51 .\" //////////////////////////////////////////////////////////////////////////
  52 .nf
  53 #include <seccomp.h>
  54
  55 int main(int argc, char *argv[])
  56 {
  57         int rc = \-1;
  58         scmp_filter_ctx ctx;
  59         int filter_fd;
  60
  61         ctx = seccomp_init(SCMP_ACT_KILL);
  62         if (ctx == NULL)
  63                 goto out;
  64
  65         /* ... */
  66
  67         filter_fd = open("/tmp/seccomp_filter.bpf", O_WRONLY);
  68         if (filter_fd == \-1) {
  69                 rc = \-errno;
  70                 goto out;
  71         }
  72
  73         rc = seccomp_export_bpf(ctx, filter_fd);
  74         if (rc < 0) {
  75                 close(filter_fd);
  76                 goto out;
  77         }
  78         close(filter_fd);
  79
  80         /* ... */
  81
  82 out:
  83         seccomp_release(ctx);
  84         return \-rc;
  85 }
  86 .fi
  87 .\" //////////////////////////////////////////////////////////////////////////
  88 .SH NOTES
  89 .\" //////////////////////////////////////////////////////////////////////////
  90 .P
  91 While the seccomp filter can be generated independent of the kernel, kernel
  92 support is required to load and enforce the seccomp filter generated by
  93 libseccomp.
  94 .P
  95 The libseccomp project site, with more information and the source code
  96 repository, can be found at https://github.com/seccomp/libseccomp.  This tool,
  97 as well as the libseccomp library, is currently under development, please
  98 report any bugs at the project site or directly to the author.
  99 .\" //////////////////////////////////////////////////////////////////////////
 100 .SH AUTHOR
 101 .\" //////////////////////////////////////////////////////////////////////////
 102 Paul Moore <paul@paul-moore.com>
 103 .\" //////////////////////////////////////////////////////////////////////////
 104 .SH SEE ALSO
 105 .\" //////////////////////////////////////////////////////////////////////////
 106 .BR seccomp_init (3),
 107 .BR seccomp_release (3)
 108