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seccomp_export_bpf(3) — Linux manual page

seccomp_export_bpf(3)    libseccomp Documentationseccomp_export_bpf(3)

NAME        top

       seccomp_export_bpf, seccomp_export_pfc - Export the seccomp filter

SYNOPSIS        top

#include <seccomp.h>typedef void * scmp_filter_ctx;int seccomp_export_bpf(const scmp_filter_ctxctx, intfd);int seccomp_export_pfc(const scmp_filter_ctxctx, intfd);int seccomp_export_bpf_mem(const scmp_filter_ctxctx, void *buf, size_t *len);       Link with-lseccomp.

DESCRIPTION        top

       Theseccomp_export_bpf() andseccomp_export_pfc() functions       generate and output the current seccomp filter in either BPF       (Berkeley Packet Filter) or PFC (Pseudo Filter Code).  The output       ofseccomp_export_bpf() is suitable for loading into the kernel,       while the output ofseccomp_export_pfc() is human readable and is       intended primarily as a debugging tool for developers using       libseccomp.  Both functions write the filter to thefd file       descriptor.       The filter contextctx is the value returned by the call toseccomp_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.       Theseccomp_export_bpf_mem() function is largely the same asseccomp_export_bpf(), but instead of writing to a file descriptor,       the program will be written to thebuf pointer provided by the       caller.  Thelen argument must be initialized with the size of thebuf buffer.  If the program was valid,len will be updated with       its size in bytes.  Ifbuf was too small to hold the program,len       can be consulted to determine the required size.  Passing a NULLbuf may also be used to query the required size ahead of time.

RETURN VALUE        top

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

EXAMPLES        top

       #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        top

       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 athttps://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        top

       Paul Moore <paul@paul-moore.com>

SEE ALSO        top

seccomp_init(3),seccomp_release(3)

COLOPHON        top

       This page is part of thelibseccomp (high-level API to the Linux       Kernel's seccomp filter) project.  Information about the project       can be found at ⟨https://github.com/seccomp/libseccomp⟩.  If you       have a bug report for this manual page, see       ⟨https://groups.google.com/d/forum/libseccomp⟩.  This page was       obtained from the project's upstream Git repository       ⟨https://github.com/seccomp/libseccomp⟩ on 2025-08-11.  (At that       time, the date of the most recent commit that was found in the       repository was 2025-05-09.)  If you discover any rendering       problems in this HTML version of the page, or you believe there is       a better or more up-to-date source for the page, or you have       corrections or improvements to the information in this COLOPHON       (which isnot part of the original manual page), send a mail to       man-pages@man7.orgpaul@paul-moore.com            30 May 2020seccomp_export_bpf(3)

Pages that refer to this page:seccomp(2)

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