Provide _NSIG, kernel_sigset_t, and kernel_sigaction (#51)

See the comments in gen/modules/general.h for details, but in short, the
definitions of `NSIG`, `sigset_t`, and `sigaction` provided by the Linux
headers don't match what's used by the `rt_sigaction` system call, so
define versions that do.

Author: sunfishcode

gen/modules/general.h

@@ -357,3 +357,25 @@ struct mmsghdr {
 #define MNT_EXPIRE      0x4
 #define UMOUNT_NOFOLLOW 0x8
 #define UMOUNT_UNUSED   0x80000000
+
+// Linux's public headers provide public `NSIG`, `sigset_t` and `sigaction`
+// definitions which "cater to libcs that poke about in kernel headers", but
+// they're not usable in libcs because, for example, `SYS_rt_sigaction` insists
+// that its fourth argument be the size of the kernel's internal `sigset_t`
+// type. So we define our own.
+
+#if defined(__i386__) || defined(__x86_64__) || defined(__s390x__) || defined(__arm__)
+#define _NSIG 64
+#endif
+
+typedef struct {
+    unsigned long sig[_NSIG / (sizeof(unsigned long) * __CHAR_BIT__)];
+} kernel_sigset_t;
+
+struct kernel_sigaction {
+    // Some platforms make `sa_handler` a macro, so use a different name.
+    __kernel_sighandler_t sa_handler_kernel;
+    unsigned long sa_flags;
+    __sigrestore_t sa_restorer;
+    kernel_sigset_t sa_mask;
+};

src/aarch64/general.rs

@@ -5254,3 +5254,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 1usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}

src/arm/general.rs

@@ -2614,6 +2614,7 @@ pub const MNT_DETACH: u32 = 2;
 pub const MNT_EXPIRE: u32 = 4;
 pub const UMOUNT_NOFOLLOW: u32 = 8;
 pub const UMOUNT_UNUSED: u32 = 2147483648;
+pub const _NSIG: u32 = 64;
 pub type size_t = crate::ctypes::c_uint;
 pub type ssize_t = crate::ctypes::c_int;
 pub type __s8 = crate::ctypes::c_schar;
@@ -5377,3 +5378,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 2usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}

src/mips/general.rs

@@ -5542,3 +5542,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 4usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}

src/mips64/general.rs

@@ -5467,3 +5467,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 2usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}

src/powerpc/general.rs

@@ -5463,3 +5463,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 2usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}

src/powerpc64/general.rs

@@ -5418,3 +5418,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 1usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}

src/riscv32/general.rs

@@ -5262,3 +5262,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 2usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}

src/riscv64/general.rs

@@ -5255,3 +5255,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 1usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}

src/s390x/general.rs

@@ -2572,6 +2572,7 @@ pub const MNT_DETACH: u32 = 2;
 pub const MNT_EXPIRE: u32 = 4;
 pub const UMOUNT_NOFOLLOW: u32 = 8;
 pub const UMOUNT_UNUSED: u32 = 2147483648;
+pub const _NSIG: u32 = 64;
 pub type size_t = crate::ctypes::c_ulong;
 pub type ssize_t = crate::ctypes::c_long;
 pub type __s8 = crate::ctypes::c_schar;
@@ -5295,3 +5296,16 @@ pub struct mmsghdr {
 pub msg_hdr: msghdr,
 pub msg_len: crate::ctypes::c_uint,
 }
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigset_t {
+pub sig: [crate::ctypes::c_ulong; 1usize],
+}
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct kernel_sigaction {
+pub sa_handler_kernel: __kernel_sighandler_t,
+pub sa_flags: crate::ctypes::c_ulong,
+pub sa_restorer: __sigrestore_t,
+pub sa_mask: kernel_sigset_t,
+}