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Berkley Packet Filter Question
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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)
