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The first `sys##name` is definition of the syscall handler function with the given name - `sys_system_call_name`. The `__SC_DECL` macro takes the `__VA_ARGS__` and combines call input parameter system type and the parameter name, because the macro definition is unable to determine the parameter types. And the `__MAP` macro applyes `__SC_DECL` macro to the `__VA_ARGS__` arguments. The other functions that are generated by the `__SYSCALL_DEFINEx` macro are need to protect from the [CVE-2009-0029](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-0029) and we will not dive into details about this here. Ok, as result of the `SYSCALL_DEFINE3` macro, we will have:
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The first `sys##name` is definition of the syscall handler function with the given name - `sys_system_call_name`. The `__SC_DECL` macro takes the `__VA_ARGS__` and combines call input parameter system type and the parameter name, because the macro definition is unable to determine the parameter types. And the `__MAP` macro applyes `__SC_DECL` macro to the `__VA_ARGS__` arguments. The other functions that are generated by the `__SYSCALL_DEFINEx` macro are need to protect from the [CVE-2009-0029](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-0029) and we will not dive into details about this here. Ok, as result of the `SYSCALL_DEFINE3` macro, we will have:
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Now we know a little about the system call's definition and we can go back to the implementation of the `write` system call. Let's look on the implementation of this system call again:
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Now we know a little about the system call's definition and we can go back to the implementation of the `write` system call. Let's look on the implementation of this system call again:
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