diff options
Diffstat (limited to 'boot/user.zig')
| -rw-r--r-- | boot/user.zig | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/boot/user.zig b/boot/user.zig index 5ba6604..9bce9e9 100644 --- a/boot/user.zig +++ b/boot/user.zig @@ -8,8 +8,7 @@ const regs = @import("regs.zig"); const bridge = @import("bridge"); const Frame = regs.Frame; -// scratch for a filename copied out of the caller. one static buffer is fine, -// syscalls run one at a time (if=0) +// scratch for a filename copied out of the caller legit one static buffer is fine var name_buf: [64]u8 = undefined; fn userName(ptr: u64) []const u8 { const p: [*]const u8 = @ptrFromInt(ptr); @@ -18,9 +17,6 @@ fn userName(ptr: u64) []const u8 { return name_buf[0..i]; } -// what the syscall stub leaves on the stack: the gp regs it pushed, then the -// frame the cpu pushed on int 0x80. rax holds the syscall number in, and the -// handler writes the return value back into it (restored by the stubs pop) pub const SyscallFrame = extern struct { r15: u64, r14: u64, @@ -49,8 +45,10 @@ pub fn installSyscall() void { idt.setGate(0x80, @intFromPtr(&syscallStub), 3, 1); // ist1: big stack for vm calls } -// save gp regs, hand the frame to the zig handler, restore, iretq. the handler -// returns via syscallframe.rax (restored by the pop below), exit() never returns +// 1- save gp regs +// 2- hand the frame to the zig handler +// 3- restore +// 4- iretq export fn syscallStub() callconv(.naked) void { asm volatile (regs.PUSH_GPRS ++ \\ @@ -120,6 +118,12 @@ export fn syscallHandler(frame: *SyscallFrame) callconv(.c) void { const dst: [*]u8 = @ptrFromInt(frame.rdx); frame.rax = bridge.fsReadInto(name, frame.rsi, dst[0..len]); }, + 6 => { // fs_write(name_ptr, buf_ptr, len): returns 1 ok / 0 fail + const len = @min(frame.rdx, 64 * 1024); + const name = userName(frame.rdi); + const src: [*]const u8 = @ptrFromInt(frame.rsi); + frame.rax = if (bridge.fsStore(name, src[0..len])) 1 else 0; + }, else => serial.write("[syscall] unknown\r\n"), } } |