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SYSCALL_HELPER_REGISTER(9) FreeBSD Kernel Developer's Manual
NAME syscall_helper_register, syscall_helper_unregister - kernel syscall registration routines
SYNOPSIS #include <sys/sysent.h>
int syscall_helper_register(struct syscall_helper_data *sd, int flags);
int syscall_helper_unregister(struct syscall_helper_data *sd);
INITIALIZER MACROS struct syscall_helper_data SYSCALL_INIT_HELPER(syscallname);
struct syscall_helper_data SYSCALL_INIT_HELPER_F(syscallname, int flags);
COMPATIBILITY INITIALIZER MACROS struct syscall_helper_data SYSCALL_INIT_HELPER_COMPAT(syscallname);
struct syscall_helper_data SYSCALL_INIT_HELPER_COMPAT_F(syscallname, int flags);
DESCRIPTION The syscall_helper_register() registers a system call. This function takes the structure struct syscall_helper_data sd, which specifies the parameters for syscall registration:
struct syscall_helper_data { struct sysent new_sysent; struct sysent old_sysent; int syscall_no; int registered; };
The only valid flag for the flags argument to syscall_helper_register() is SY_THR_STATIC. This flag prevents the syscall from being unregistered.
Before use, the structure must be initialized with one of the SYSCALL_INIT_HELPER*() macros. In new code, syscall implementation functions shall be named sys_syscallname() and the regular macros shall be used.
For legacy syscall functions named without "sys_" prefixes, the "COMPAT" versions of the macros may be used.
The only valid flag for the flags argument to the "F" variants of the initializer macros is SYF_CAPENABLED. This flag indicates that the syscall is allowed in capability mode.
The syscall_helper_unregister() unregisters a system call. This function takes the same structure struct syscall_helper_data sd that was
ERRORS The syscall_helper_register() call will fail and the syscall will not be registered if:
[EINVAL] The flags argument contained a value other than SY_THR_STATIC.
[EINVAL] The specified syscall number, sd.syscall_no (SYS_syscallname), was outside of the valid range of system call numbers (zero through SYS_MAXSYSCALL).
[ENFILE] The system call table does not have any available slots.
[EEXIST] The specified syscall number, sd.syscall_no (SYS_syscallname), was already in use.
SEE ALSO SYSCALL_MODULE(9)
FreeBSD 14.0-RELEASE-p11 February 10, 2018 FreeBSD 14.0-RELEASE-p11