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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLES | NOTES | AUTHOR | SEE ALSO | COLOPHON |
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seccomp_init(3) libseccomp Documentation seccomp_init(3)
seccomp_init, seccomp_reset - Initialize the seccomp filter state
#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.
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. If seccomp_reset() is called with a NULL filter, it
resets the library's global task state, including any notification
file descriptors retrieved by seccomp_notify_fd(3). Normally this
is not needed, but it may be required to continue using the
library after a fork() or clone() call to ensure the API level and
user notification state is properly reset.
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 thread will be terminated by the kernel with SIGSYS
when it calls a syscall that does not match any of the
configured seccomp filter rules. The thread will not be
able to catch the signal.
SCMP_ACT_KILL_PROCESS
The entire process will be terminated by the kernel with
SIGSYS when it calls a syscall that does not match any of
the configured seccomp filter rules.
SCMP_ACT_TRAP
The thread will be sent a SIGSYS signal when it calls a
syscall that does not match any of the configured seccomp
filter rules. It may catch this and change its behavior
accordingly. When using SA_SIGINFO with sigaction(2),
si_code will be set to SYS_SECCOMP, si_syscall will be set
to the syscall that failed the rules, and si_arch will be
set to the AUDIT_ARCH for the active ABI.
SCMP_ACT_ERRNO(uint16_t errno)
The thread 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 thread 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_LOG
The seccomp filter will have no effect on the thread
calling the syscall if it does not match any of the
configured seccomp filter rules but the syscall will be
logged.
SCMP_ACT_ALLOW
The seccomp filter will have no effect on the thread
calling the syscall if it does not match any of the
configured seccomp filter rules.
The seccomp_init() function returns a filter context on success,
NULL on failure. The seccomp_reset() function returns zero on
success or one of the following error codes on failure:
-EINVAL
Invalid input, either the context or action is invalid.
-ENOMEM
The library was unable to allocate enough memory.
#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;
}
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.
Paul Moore <[email protected]>
seccomp_release(3)
This page is part of the libseccomp (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 is not part of the original manual page), send a mail to
[email protected]
[email protected] 30 May 2020 seccomp_init(3)
Pages that refer to this page: seccomp(2), seccomp_arch_add(3), seccomp_attr_set(3), seccomp_export_bpf(3), seccomp_load(3), seccomp_merge(3), seccomp_release(3), seccomp_rule_add(3), seccomp_transaction_start(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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