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 generated 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)