projects / linux-seccomp.git / blame
| Commit | Line | Data |
|---|---|---|
| 8befd5cc MG |
1 | .TH "seccomp_syscall_priority" 3 "25 July 2012" "paul@paul-moore.com" "libseccomp Documentation" |
| 2 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 3 | .SH NAME | |
| 4 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 5 | seccomp_syscall_priority \- Prioritize syscalls in the seccomp filter | |
| 6 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 7 | .SH SYNOPSIS | |
| 8 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 9 | .nf | |
| 10 | .B #include <seccomp.h> | |
| 11 | .sp | |
| 12 | .B typedef void * scmp_filter_ctx; | |
| 13 | .sp | |
| 14 | .BI "int SCMP_SYS(" syscall_name ");" | |
| 15 | .sp | |
| 16 | .BI "int seccomp_syscall_priority(scmp_filter_ctx " ctx "," | |
| 17 | .BI " int " syscall ", uint8_t " priority ");" | |
| 18 | .sp | |
| 19 | Link with \fI\-lseccomp\fP. | |
| 20 | .fi | |
| 21 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 22 | .SH DESCRIPTION | |
| 23 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 24 | .P | |
| 25 | The | |
| 26 | .BR seccomp_syscall_priority () | |
| 27 | function provides a priority hint to the seccomp filter generator in libseccomp | |
| 28 | such that higher priority syscalls are placed earlier in the seccomp filter code | |
| 29 | so that they incur less overhead at the expense of lower priority syscalls. A | |
| 30 | syscall's priority can be set regardless of if any rules currently exist for | |
| 31 | that syscall; the library will remember the priority and it will be assigned to | |
| 32 | the syscall if and when a rule for that syscall is created. | |
| 33 | .P | |
| 34 | While it is possible to specify the | |
| 35 | .I syscall | |
| 36 | value directly using the standard | |
| 37 | .B __NR_syscall | |
| 38 | values, in order to ensure proper operation across multiple architectures it | |
| 39 | is highly recommended to use the | |
| 40 | .BR SCMP_SYS () | |
| 41 | macro instead. See the EXAMPLES section below. | |
| 42 | .P | |
| 43 | The | |
| 44 | .I priority | |
| 45 | parameter takes an 8-bit value ranging from 0 \- 255; a higher value represents | |
| 46 | a higher priority. | |
| 47 | .P | |
| 48 | The filter context | |
| 49 | .I ctx | |
| 50 | is the value returned by the call to | |
| 51 | .BR seccomp_init (). | |
| 52 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 53 | .SH RETURN VALUE | |
| 54 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 55 | The | |
| 56 | .BR seccomp_syscall_priority () | |
| 57 | function returns zero on success, negative errno values on failure. The | |
| 58 | .BR SCMP_SYS () | |
| 59 | macro returns a value suitable for use as the | |
| 60 | .I syscall | |
| 61 | value in | |
| 62 | .BR seccomp_syscall_priority (). | |
| 63 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 64 | .SH EXAMPLES | |
| 65 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 66 | .nf | |
| 67 | #include <seccomp.h> | |
| 68 | ||
| 69 | int main(int argc, char *argv[]) | |
| 70 | { | |
| 71 | int rc = \-1; | |
| 72 | scmp_filter_ctx ctx; | |
| 73 | ||
| 74 | ctx = seccomp_init(SCMP_ACT_KILL); | |
| 75 | if (ctx == NULL) | |
| 76 | goto out; | |
| 77 | ||
| 78 | /* ... */ | |
| 79 | ||
| 80 | rc = seccomp_syscall_priority(ctx, SCMP_SYS(read), 200); | |
| 81 | if (rc < 0) | |
| 82 | goto out; | |
| 83 | ||
| 84 | /* ... */ | |
| 85 | ||
| 86 | out: | |
| 87 | seccomp_release(ctx); | |
| 88 | return \-rc; | |
| 89 | } | |
| 90 | .fi | |
| 91 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 92 | .SH NOTES | |
| 93 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 94 | .P | |
| 95 | While the seccomp filter can be generated independent of the kernel, kernel | |
| 96 | support is required to load and enforce the seccomp filter generated by | |
| 97 | libseccomp. | |
| 98 | .P | |
| 99 | The libseccomp project site, with more information and the source code | |
| 100 | repository, can be found at https://github.com/seccomp/libseccomp. This tool, | |
| 101 | as well as the libseccomp library, is currently under development, please | |
| 102 | report any bugs at the project site or directly to the author. | |
| 103 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 104 | .SH AUTHOR | |
| 105 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 106 | Paul Moore <paul@paul-moore.com> | |
| 107 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 108 | .SH SEE ALSO | |
| 109 | .\" ////////////////////////////////////////////////////////////////////////// | |
| 110 | .BR seccomp_rule_add (3), | |
| 111 | .BR seccomp_rule_add_exact (3) |