reset signal handlers in Bun.spawn (#4405)

* see if this fixes it

* We don't need this

* Remove extra flag

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

3 files changed, 53 insertions, 8 deletions

diff --git a/src/bun.js/api/bun/spawn.zig b/src/bun.js/api/bun/spawn.zig
index e5678ec44..8a8ec3fff 100644
--- a/src/bun.js/api/bun/spawn.zig
+++ b/src/bun.js/api/bun/spawn.zig
@@ -75,6 +75,14 @@ pub const PosixSpawn = struct {
                 else => |err| return unexpectedErrno(err),
             }
         }
+
+        pub fn resetSignals(this: *Attr) !void {
+            if (posix_spawnattr_reset_signals(&this.attr) != 0) {
+                return error.SystemResources;
+            }
+        }
+
+        extern fn posix_spawnattr_reset_signals(attr: *system.posix_spawnattr_t) c_int;
     };
 
     pub const Actions = struct {
diff --git a/src/bun.js/api/bun/subprocess.zig b/src/bun.js/api/bun/subprocess.zig
index 2ee94a222..c3244131d 100644
--- a/src/bun.js/api/bun/subprocess.zig
+++ b/src/bun.js/api/bun/subprocess.zig
@@ -1070,6 +1070,7 @@ pub const Subprocess = struct {
         var PATH = jsc_vm.bundler.env.get("PATH") orelse "";
         var argv: std.ArrayListUnmanaged(?[*:0]const u8) = undefined;
         var cmd_value = JSValue.zero;
+        var detached: bool = false;
         var args = args_;
         {
             if (args.isEmptyOrUndefinedOrNull()) {
@@ -1243,6 +1244,12 @@ pub const Subprocess = struct {
                         }
                     }
                 }
+
+                if (args.get(globalThis, "detached")) |detached_val| {
+                    if (detached_val.isBoolean()) {
+                        detached = detached_val.toBoolean();
+                    }
+                }
             }
         }
 
@@ -1251,17 +1258,29 @@ pub const Subprocess = struct {
             return .zero;
         };
 
+        var flags: i32 = bun.C.POSIX_SPAWN_SETSIGDEF | bun.C.POSIX_SPAWN_SETSIGMASK;
+
+        if (comptime Environment.isMac) {
+            flags |= bun.C.POSIX_SPAWN_CLOEXEC_DEFAULT;
+        }
+
+        if (detached) {
+            flags |= bun.C.POSIX_SPAWN_SETSID;
+        }
+
         defer attr.deinit();
         var actions = PosixSpawn.Actions.init() catch |err| return globalThis.handleError(err, "in posix_spawn");
         if (comptime Environment.isMac) {
-            attr.set(
-                bun.C.POSIX_SPAWN_CLOEXEC_DEFAULT | bun.C.POSIX_SPAWN_SETSIGDEF | bun.C.POSIX_SPAWN_SETSIGMASK,
-            ) catch |err| return globalThis.handleError(err, "in posix_spawn");
+            attr.set(@intCast(flags)) catch |err| return globalThis.handleError(err, "in posix_spawn");
         } else if (comptime Environment.isLinux) {
-            attr.set(
-                bun.C.linux.POSIX_SPAWN.SETSIGDEF | bun.C.linux.POSIX_SPAWN.SETSIGMASK,
-            ) catch |err| return globalThis.handleError(err, "in posix_spawn");
+            attr.set(@intCast(flags)) catch |err| return globalThis.handleError(err, "in posix_spawn");
         }
+
+        attr.resetSignals() catch {
+            globalThis.throw("Failed to reset signals in posix_spawn", .{});
+            return .zero;
+        };
+
         defer actions.deinit();
 
         if (!override_env and env_array.items.len == 0) {
@@ -1344,14 +1363,14 @@ pub const Subprocess = struct {
             const kernel = @import("../../../analytics.zig").GenerateHeader.GeneratePlatform.kernelVersion();
 
             // pidfd_nonblock only supported in 5.10+
-            const flags: u32 = if (!is_sync and kernel.orderWithoutTag(.{ .major = 5, .minor = 10, .patch = 0 }).compare(.gte))
+            const pidfd_flags: u32 = if (!is_sync and kernel.orderWithoutTag(.{ .major = 5, .minor = 10, .patch = 0 }).compare(.gte))
                 std.os.O.NONBLOCK
             else
                 0;
 
             const fd = std.os.linux.pidfd_open(
                 pid,
-                flags,
+                pidfd_flags,
             );
 
             switch (std.os.linux.getErrno(fd)) {
diff --git a/src/bun.js/bindings/spawn.cpp b/src/bun.js/bindings/spawn.cpp
new file mode 100644
index 000000000..531941f8a
--- /dev/null
+++ b/src/bun.js/bindings/spawn.cpp
@@ -0,0 +1,18 @@
+#include <spawn.h>
+#include <signal.h>
+
+extern "C" int posix_spawnattr_reset_signals(posix_spawnattr_t* attr)
+{
+    sigset_t signal_set;
+    sigfillset(&signal_set);
+    if (posix_spawnattr_setsigdefault(attr, &signal_set) != 0) {
+        return 1;
+    }
+
+    sigemptyset(&signal_set);
+    if (posix_spawnattr_setsigmask(attr, &signal_set) != 0) {
+        return 1;
+    }
+
+    return 0;
+}