Every child starts with its signals at their defaults and none blocked

Shells, command panes, language servers, the link opener and the v9fs mount inherited the editor's signal mask (the tty's blocked SIGWINCH) and anything it ignored (a SIGHUP nohup ignored), since only handlers reset at exec. Each fork now resets every disposition and clears the mask before its exec (resetChildSignals); std's spawn for selection pipes runs with the mask cleared across it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/linux/v9fs.zig b/src/linux/v9fs.zig
index 4e18660d..5e031bfe 100644
--- a/src/linux/v9fs.zig
+++ b/src/linux/v9fs.zig
@@ -118,6 +118,16 @@ fn launch(arena: std.mem.Allocator, args: []const [:0]const u8) !u8 {
     const pid = fork();
     if (pid < 0) return error.ForkFailed;
     if (pid == 0) {
+        // host_io's resetChildSignals, here in its own module: every signal
+        // back to its default and none blocked before the exec.
+        const default: std.posix.Sigaction = .{ .handler = .{ .handler = std.posix.SIG.DFL }, .mask = std.posix.sigemptyset(), .flags = 0 };
+        var sig: u8 = 1;
+        while (sig < 65) : (sig += 1) {
+            if (sig == @intFromEnum(std.posix.SIG.KILL) or sig == @intFromEnum(std.posix.SIG.STOP)) continue;
+            _ = std.c.sigaction(@enumFromInt(sig), &default, null);
+        }
+        const none = std.posix.sigemptyset();
+        std.posix.sigprocmask(std.posix.SIG.SETMASK, &none, null);
         _ = execvp("sudo", argv.ptr);
         _exit(127);
     }