# seccomp_export_bpf

## 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_**);**
           **int seccomp_export_bpf_mem(const scmp_filter_ctx** _ctx_**, void ***_buf_**, size_t ***_len_**);**
    
           Link with _-lseccomp_.
    


## DESCRIPTION



           The **seccomp_export_bpf**() and **seccomp_export_pfc**() functions
           generate and output the current seccomp filter in either BPF
           (Berkeley Packet Filter) or PFC (Pseudo Filter Code).  The output
           of **seccomp_export_bpf**() is suitable for loading into the kernel,
           while the output of **seccomp_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
           instructions, and their ordering, are not guaranteed to be the
           same in both the BPF and PFC formats.
    
           The **seccomp_export_bpf_mem**() function is largely the same as
           **seccomp_export_bpf**(), but instead of writing to a file descriptor,
           the program will be written to the _buf_ pointer provided by the
           caller.  The _len_ argument must be initialized with the size of the
           _buf_ buffer.  If the program was valid, _len_ will be updated with
           its size in bytes.  If _buf_ was too small to hold the program, _len_
           can be consulted to determine the required size.  Passing a NULL
           _buf_ may also be used to query the required size ahead of time.
    


## RETURN VALUE



           Return 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.
    
           **-ERANGE**
                  The provided buffer was too small.
    
           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;
                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 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.
    


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