1 files changed, 65 insertions, 0 deletions
diff --git a/src/bun.js/node/syscall.zig b/src/bun.js/node/syscall.zig
index 7ad927c3a..14cee4e36 100644
--- a/src/bun.js/node/syscall.zig
+++ b/src/bun.js/node/syscall.zig
@@ -203,6 +203,7 @@ pub fn open(file_path: [:0]const u8, flags: JSC.Node.Mode, perm: JSC.Node.Mode)
 // The zig standard library marks BADF as unreachable
 // That error is not unreachable for us
 pub fn close(fd: std.os.fd_t) ?Syscall.Error {
+    log("close({d})", .{fd});
     if (comptime Environment.isMac) {
         // This avoids the EINTR problem.
         return switch (system.getErrno(system.@"close$NOCANCEL"(fd))) {
@@ -682,3 +683,67 @@ pub const Error = struct {
         return this.toSystemError().toErrorInstance(ptr);
     }
 };
+
+pub fn setPipeCapacityOnLinux(fd: JSC.Node.FileDescriptor, capacity: usize) Maybe(usize) {
+    if (comptime !Environment.isLinux) @compileError("Linux-only");
+    std.debug.assert(capacity > 0);
+
+    // In  Linux  versions  before 2.6.11, the capacity of a
+    // pipe was the same as the system page size (e.g., 4096
+    // bytes on i386).  Since Linux 2.6.11, the pipe
+    // capacity is 16 pages (i.e., 65,536 bytes in a system
+    // with a page size of 4096 bytes).  Since Linux 2.6.35,
+    // the default pipe capacity is 16 pages, but the
+    // capacity can be queried  and  set  using  the
+    // fcntl(2) F_GETPIPE_SZ and F_SETPIPE_SZ operations.
+    // See fcntl(2) for more information.
+    //:# define F_SETPIPE_SZ    1031    /* Set pipe page size array.
+    const F_SETPIPE_SZ = 1031;
+    const F_GETPIPE_SZ = 1032;
+
+    // We don't use glibc here
+    // It didn't work. Always returned 0.
+    const pipe_len = std.os.linux.fcntl(fd, F_GETPIPE_SZ, 0);
+    if (Maybe(usize).errno(pipe_len)) |err| return err;
+    if (pipe_len == 0) return Maybe(usize){ .result = 0 };
+    if (pipe_len >= capacity) return Maybe(usize){ .result = pipe_len };
+
+    const new_pipe_len = std.os.linux.fcntl(fd, F_SETPIPE_SZ, capacity);
+    if (Maybe(usize).errno(new_pipe_len)) |err| return err;
+    return Maybe(usize){ .result = new_pipe_len };
+}
+
+pub fn getMaxPipeSizeOnLinux() usize {
+    return @intCast(
+        usize,
+        bun.once(struct {
+            fn once() c_int {
+                const strings = bun.strings;
+                const default_out_size = 512 * 1024;
+                const pipe_max_size_fd = switch (JSC.Node.Syscall.open("/proc/sys/fs/pipe-max-size", std.os.O.RDONLY, 0)) {
+                    .result => |fd2| fd2,
+                    .err => |err| {
+                        log("Failed to open /proc/sys/fs/pipe-max-size: {d}\n", .{err.errno});
+                        return default_out_size;
+                    },
+                };
+                defer _ = JSC.Node.Syscall.close(pipe_max_size_fd);
+                var max_pipe_size_buf: [128]u8 = undefined;
+                const max_pipe_size = switch (JSC.Node.Syscall.read(pipe_max_size_fd, max_pipe_size_buf[0..])) {
+                    .result => |bytes_read| std.fmt.parseInt(i64, strings.trim(max_pipe_size_buf[0..bytes_read], "\n"), 10) catch |err| {
+                        log("Failed to parse /proc/sys/fs/pipe-max-size: {any}\n", .{@errorName(err)});
+                        return default_out_size;
+                    },
+                    .err => |err| {
+                        log("Failed to read /proc/sys/fs/pipe-max-size: {d}\n", .{err.errno});
+                        return default_out_size;
+                    },
+                };
+
+                // we set the absolute max to 8 MB because honestly that's a huge pipe
+                // my current linux machine only goes up to 1 MB, so that's very unlikely to be hit
+                return @minimum(@truncate(c_int, max_pipe_size -| 32), 1024 * 1024 * 8);
+            }
+        }.once, c_int),
+    );
+}