seccomp_export_pfc(3) [centos man page]

seccomp_export_bpf(3)					     libseccomp Documentation					     seccomp_export_bpf(3)

NAME

       seccomp_export_bpf, seccomp_export_pfc - Export the seccomp filter

SYNOPSIS

       #include <seccomp.h>

       typedef void * scmp_filter_ctx;

       int seccomp_export_bpf(const scmp_filter_ctx ctx, int fd);
       int seccomp_export_pfc(const scmp_filter_ctx ctx, int fd);

       Link with -lseccomp.

DESCRIPTION

       The  seccomp_export_bpf()  and  seccomp_export_pfc() functions generate and output the current seccomp filter in either BPF (Berkley Packet
       Filter) or PFC (Pseudo Filter Code).  The output of seccomp_export_bpf() is suitable for loading into the kernel, while the output of  sec-
       comp_export_pfc()  is  human  readable and is intended primarily as a debugging tool for developers using libseccomp.  Both functions write
       the filter to the fd file descriptor.

       The filter context ctx is the value returned by the call to seccomp_init(3).

       While the two output formats are guaranteed to be functionally equivalent for the given seccomp filter configuration, the  filter  instruc-
       tions, and their ordering, are not guaranteed to be the same in both the BPF and PFC formats.

RETURN VALUE

       Returns zero on success, negative errno values on failure.

EXAMPLES

       #include <seccomp.h>

       int main(int argc, char *argv[])
       {
	    int rc = -1;
	    scmp_filter_ctx ctx;
	    int filter_fd;

	    ctx = seccomp_init(SCMP_ACT_KILL);
	    if (ctx == NULL)
		 goto out;

	    /* ... */

	    filter_fd = open("/tmp/seccomp_filter.bpf", O_WRONLY);
	    if (filter_fd == -1) {
		 rc = -errno;
		 goto out;
	    }

	    rc = seccomp_export_bpf(ctx, filter_fd);
	    if (rc < 0) {
		 close(filter_fd);
		 goto out;
	    }
	    close(filter_fd);

	    /* ... */

       out:
	    seccomp_release(ctx);
	    return -rc;
       }

NOTES

       While the seccomp filter can be generated independent of the kernel, kernel support is required to load and enforce the seccomp filter gen-
       erated by libseccomp.

       The libseccomp project site, with more information and the source code repository, can be found at http://libseccomp.sf.net.  This  library
       is currently under development, please report any bugs at the project site or directly to the author.

AUTHOR

       Paul Moore <paul@paul-moore.com>

SEE ALSO

       seccomp_init(3), seccomp_release(3)

paul@paul-moore.com						   25 July 2012 					     seccomp_export_bpf(3)

seccomp_init(3) 					     libseccomp Documentation						   seccomp_init(3)

NAME

       seccomp_init, seccomp_reset - Initialize the seccomp filter state

SYNOPSIS

       #include <seccomp.h>

       typedef void * scmp_filter_ctx;

       scmp_filter_ctx seccomp_init(uint32_t def_action);
       int seccomp_reset(scmp_filter_ctx ctx, uint32_t def_action);

       Link with -lseccomp.

DESCRIPTION

       The  seccomp_init()  and  seccomp_reset()  functions  (re)initialize  the  internal seccomp filter state, prepares it for use, and sets the
       default action based on the def_action parameter.  The seccomp_init() function must be called before any other libseccomp functions as  the
       rest  of  the  library API will fail if the filter context is not initialized properly.	The seccomp_reset() function releases the existing
       filter context state before reinitializing it and can only be called after a call to seccomp_init() has succeeded.

       When the caller is finished configuring the seccomp filter and has loaded it into the kernel, the caller should call seccomp_release(3)	to
       release all of the filter context state.

       Valid def_action values are as follows:

       SCMP_ACT_KILL
	      The process will be killed by the kernel when it calls a syscall that does not match any of the configured seccomp filter rules.

       SCMP_ACT_TRAP
	      The process will throw a SIGSYS signal when it calls a syscall that does not match any of the configured seccomp filter rules.

       SCMP_ACT_ERRNO(uint16_t errno)
	      The  process  will  receive a return value of errno when it calls a syscall that does not match any of the configured seccomp filter
	      rules.

       SCMP_ACT_TRACE(uint16_t msg_num)
	      If the process is being traced and the tracing process specified the PTRACE_O_TRACESECCOMP option in  the  call  to  ptrace(2),  the
	      tracing  process	will  be  notified,  via  PTRACE_EVENT_SECCOMP	,  and	the  value  provided in msg_num can be retrieved using the
	      PTRACE_GETEVENTMSG option.

       SCMP_ACT_ALLOW
	      The seccomp filter will have no effect on the process calling the syscall if it does not match any of the configured seccomp  filter
	      rules.

RETURN VALUE

       The  seccomp_init()  function  returns a filter context on success, NULL on failure.  The seccomp_reset() function returns zero on success,
       negative errno values on failure.

EXAMPLES

       #include <seccomp.h>

       int main(int argc, char *argv[])
       {
	    int rc = -1;
	    scmp_filter_ctx ctx;

	    ctx = seccomp_init(SCMP_ACT_KILL);
	    if (ctx == NULL)
		 goto out;

	    /* ... */

	    rc = seccomp_reset(ctx, SCMP_ACT_KILL);
	    if (rc < 0)
		 goto out;

	    /* ... */

       out:
	    seccomp_release(ctx);
	    return -rc;
       }

NOTES

       While the seccomp filter can be generated independent of the kernel, kernel support is required to load and enforce the seccomp filter gen-
       erated by libseccomp.

       The  libseccomp project site, with more information and the source code repository, can be found at http://libseccomp.sf.net.  This library
       is currently under development, please report any bugs at the project site or directly to the author.

AUTHOR

       Paul Moore <paul@paul-moore.com>

SEE ALSO

       seccomp_release(3)

paul@paul-moore.com						   25 July 2012 						   seccomp_init(3)