NAME

       seccomp_precompute - Precompute the current seccomp filter

SYNOPSIS

       #include <seccomp.h>

       typedef void * scmp_filter_ctx;

       int seccomp_precompute(scmp_filter_ctx ctx);

       Link with -lseccomp.

DESCRIPTION

       Precomputes the seccomp filter for later use by seccomp_load() and similar functions.  Not only does this
       improve  performance of seccomp_load() it also ensures that the seccomp filter can be loaded in an async-
       signal-safe manner if no changes have been made to the filter since it was precomputed.

RETURN VALUE

       Returns zero on success or one of the following error codes on failure:

       -ECANCELED
              There was a system failure beyond the control of the library.

       -EFAULT
              Internal libseccomp failure.

       -EINVAL
              Invalid input, either the context or architecture token is invalid.

       -ENOMEM
              The library was unable to allocate enough memory.

       If the SCMP_FLTATR_API_SYSRAWRC filter attribute is non-zero then additional error codes may be  returned
       to  the  caller;  these  additional  error  codes  are  the negative errno values returned by the system.
       Unfortunately libseccomp can make no guarantees about these return values.

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_precompute(ctx);
            if (rc < 0)
                 goto out;

            /* ... */

            rc = seccomp_load(ctx);
            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
       https://github.com/seccomp/libseccomp.  This tool, as well as the libseccomp 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_load(3) signal-safety(7)

paul@paul-moore.com                             19 September 2022                          seccomp_precompute(3)