dup and close file descriptors (#5341)

* track one shot fds

* dup fd

* skip for rearm on mac

* dup if fd

* cleanup

* force unregister on close

* deinitForceUnregister

* test

* add prompts

---------

Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>

2 files changed, 41 insertions, 35 deletions

diff --git a/src/bun.js/base.zig b/src/bun.js/base.zig
index a6df36c4f..26d5d74c3 100644
--- a/src/bun.js/base.zig
+++ b/src/bun.js/base.zig
@@ -1787,12 +1787,19 @@ pub const FilePoll = struct {
 
     pub fn deinit(this: *FilePoll) void {
         var vm = JSC.VirtualMachine.get();
-        this.deinitWithVM(vm);
+        var loop = vm.event_loop_handle.?;
+        this.deinitPossiblyDefer(vm, loop, vm.rareData().filePolls(vm), false);
+    }
+
+    pub fn deinitForceUnregister(this: *FilePoll) void {
+        var vm = JSC.VirtualMachine.get();
+        var loop = vm.event_loop_handle.?;
+        this.deinitPossiblyDefer(vm, loop, vm.rareData().filePolls(vm), true);
     }
 
-    fn deinitPossiblyDefer(this: *FilePoll, vm: *JSC.VirtualMachine, loop: *uws.Loop, polls: *JSC.FilePoll.Store) void {
+    fn deinitPossiblyDefer(this: *FilePoll, vm: *JSC.VirtualMachine, loop: *uws.Loop, polls: *JSC.FilePoll.Store, force_unregister: bool) void {
         if (this.isRegistered()) {
-            _ = this.unregister(loop);
+            _ = this.unregister(loop, force_unregister);
         }
 
         this.owner = Deactivated.owner;
@@ -1804,7 +1811,7 @@ pub const FilePoll = struct {
 
     pub fn deinitWithVM(this: *FilePoll, vm: *JSC.VirtualMachine) void {
         var loop = vm.event_loop_handle.?;
-        this.deinitPossiblyDefer(vm, loop, vm.rareData().filePolls(vm));
+        this.deinitPossiblyDefer(vm, loop, vm.rareData().filePolls(vm), false);
     }
 
     pub fn isRegistered(this: *const FilePoll) bool {
@@ -2168,10 +2175,12 @@ pub const FilePoll = struct {
 
             var event = linux.epoll_event{ .events = flags, .data = .{ .u64 = @intFromPtr(Pollable.init(this).ptr()) } };
 
+            var op: u32 = if (this.isRegistered() or this.flags.contains(.needs_rearm)) linux.EPOLL.CTL_MOD else linux.EPOLL.CTL_ADD;
+
             const ctl = linux.epoll_ctl(
                 watcher_fd,
-                if (this.isRegistered() or this.flags.contains(.needs_rearm)) linux.EPOLL.CTL_MOD else linux.EPOLL.CTL_ADD,
-                @as(std.os.fd_t, @intCast(fd)),
+                op,
+                @intCast(fd),
                 &event,
             );
             this.flags.insert(.was_ever_registered);
@@ -2285,11 +2294,11 @@ pub const FilePoll = struct {
 
     const invalid_fd = bun.invalid_fd;
 
-    pub fn unregister(this: *FilePoll, loop: *uws.Loop) JSC.Maybe(void) {
-        return this.unregisterWithFd(loop, this.fd);
+    pub fn unregister(this: *FilePoll, loop: *uws.Loop, force_unregister: bool) JSC.Maybe(void) {
+        return this.unregisterWithFd(loop, this.fd, force_unregister);
     }
 
-    pub fn unregisterWithFd(this: *FilePoll, loop: *uws.Loop, fd: bun.UFileDescriptor) JSC.Maybe(void) {
+    pub fn unregisterWithFd(this: *FilePoll, loop: *uws.Loop, fd: bun.UFileDescriptor, force_unregister: bool) JSC.Maybe(void) {
         if (!(this.flags.contains(.poll_readable) or this.flags.contains(.poll_writable) or this.flags.contains(.poll_process) or this.flags.contains(.poll_machport))) {
             // no-op
             return JSC.Maybe(void).success;
@@ -2310,7 +2319,7 @@ pub const FilePoll = struct {
             return JSC.Maybe(void).success;
         };
 
-        if (this.flags.contains(.needs_rearm)) {
+        if (this.flags.contains(.needs_rearm) and !force_unregister) {
             log("unregister: {s} ({d}) skipped due to needs_rearm", .{ @tagName(flag), fd });
             this.flags.remove(.poll_process);
             this.flags.remove(.poll_readable);
@@ -2325,7 +2334,7 @@ pub const FilePoll = struct {
             const ctl = linux.epoll_ctl(
                 watcher_fd,
                 linux.EPOLL.CTL_DEL,
-                @as(std.os.fd_t, @intCast(fd)),
+                @intCast(fd),
                 null,
             );
 
diff --git a/src/bun.js/webcore/streams.zig b/src/bun.js/webcore/streams.zig
index a578313d7..b96721e6e 100644
--- a/src/bun.js/webcore/streams.zig
+++ b/src/bun.js/webcore/streams.zig
@@ -3788,7 +3788,6 @@ pub const FIFO = struct {
     },
     signal: JSC.WebCore.Signal = .{},
     is_first_read: bool = true,
-    auto_close: bool = true,
     has_adjusted_pipe_size_on_linux: bool = false,
     drained: bool = true,
 
@@ -3807,7 +3806,12 @@ pub const FIFO = struct {
     pub fn close(this: *FIFO) void {
         if (this.poll_ref) |poll| {
             this.poll_ref = null;
-            poll.deinit();
+            if (comptime Environment.isLinux) {
+                // force target fd to be removed from epoll
+                poll.deinitForceUnregister();
+            } else {
+                poll.deinit();
+            }
         }
 
         const fd = this.fd;
@@ -3815,8 +3819,7 @@ pub const FIFO = struct {
         defer if (signal_close) this.signal.close(null);
         if (signal_close) {
             this.fd = bun.invalid_fd;
-            if (this.auto_close)
-                _ = bun.sys.close(fd);
+            _ = bun.sys.close(fd);
         }
 
         this.to_read = null;
@@ -4198,10 +4201,15 @@ pub const File = struct {
         file: *Blob.FileStore,
     ) StreamStart {
         var file_buf: [std.fs.MAX_PATH_BYTES]u8 = undefined;
-        var auto_close = file.pathlike == .path;
 
-        var fd = if (!auto_close)
-            file.pathlike.fd
+        var fd = if (file.pathlike != .path)
+            // We will always need to close the file descriptor.
+            switch (Syscall.dup(@intCast(file.pathlike.fd))) {
+                .result => |_fd| _fd,
+                .err => |err| {
+                    return .{ .err = err.withPath(file.pathlike.path.slice()) };
+                },
+            }
         else switch (Syscall.open(file.pathlike.path.sliceZ(&file_buf), std.os.O.RDONLY | std.os.O.NONBLOCK | std.os.O.CLOEXEC, 0)) {
             .result => |_fd| _fd,
             .err => |err| {
@@ -4218,7 +4226,7 @@ pub const File = struct {
             }
         }
 
-        if (!auto_close and !(file.is_atty orelse false)) {
+        if (file.pathlike != .path and !(file.is_atty orelse false)) {
             if (comptime Environment.isWindows) {
                 bun.todo(@src(), {});
             } else {
@@ -4229,7 +4237,6 @@ pub const File = struct {
                         // if we do not, clone the descriptor and set non-blocking
                         // it is important for us to clone it so we don't cause Weird Things to happen
                         if ((flags & std.os.O.NONBLOCK) == 0) {
-                            auto_close = true;
                             fd = switch (Syscall.fcntl(fd, std.os.F.DUPFD, 0)) {
                                 .result => |_fd| @as(@TypeOf(fd), @intCast(_fd)),
                                 .err => |err| return .{ .err = err },
@@ -4249,24 +4256,18 @@ pub const File = struct {
             const stat: bun.Stat = switch (Syscall.fstat(fd)) {
                 .result => |result| result,
                 .err => |err| {
-                    if (auto_close) {
-                        _ = Syscall.close(fd);
-                    }
+                    _ = Syscall.close(fd);
                     return .{ .err = err };
                 },
             };
 
             if (std.os.S.ISDIR(stat.mode)) {
-                if (auto_close) {
-                    _ = Syscall.close(fd);
-                }
+                _ = Syscall.close(fd);
                 return .{ .err = Syscall.Error.fromCode(.ISDIR, .fstat) };
             }
 
             if (std.os.S.ISSOCK(stat.mode)) {
-                if (auto_close) {
-                    _ = Syscall.close(fd);
-                }
+                _ = Syscall.close(fd);
                 return .{ .err = Syscall.Error.fromCode(.INVAL, .fstat) };
             }
 
@@ -4292,9 +4293,7 @@ pub const File = struct {
             file.max_size = this.remaining_bytes;
 
             if (this.remaining_bytes == 0) {
-                if (auto_close) {
-                    _ = Syscall.close(fd);
-                }
+                _ = Syscall.close(fd);
 
                 return .{ .empty = {} };
             }
@@ -4303,7 +4302,6 @@ pub const File = struct {
         }
 
         this.fd = fd;
-        this.auto_close = auto_close;
 
         return StreamStart{ .ready = {} };
     }
@@ -4725,7 +4723,6 @@ pub const FileReader = struct {
                             .readable = .{
                                 .FIFO = .{
                                     .fd = readable_file.fd,
-                                    .auto_close = readable_file.auto_close,
                                     .drained = this.buffered_data.len == 0,
                                 },
                             },
@@ -4885,7 +4882,7 @@ pub fn NewReadyWatcher(
             const fd = @as(c_int, @intCast(fd_));
             std.debug.assert(@as(c_int, @intCast(this.poll_ref.?.fd)) == fd);
             std.debug.assert(
-                this.poll_ref.?.unregister(JSC.VirtualMachine.get().event_loop_handle.?) == .result,
+                this.poll_ref.?.unregister(JSC.VirtualMachine.get().event_loop_handle.?, false) == .result,
             );
         }