From ec782f684297be63fc6df61e3706f7db9d7879b9 Mon Sep 17 00:00:00 2001
From: Hood Chatham <roberthoodchatham@gmail.com>
Date: Fri, 8 Nov 2024 10:51:46 +0100
Subject: [PATCH 1/2] Make seek work on `/dev/null`

Seeking `/dev/null` should work and do nothing instead of returning `EPIPE`.
This fixes it.
---
 src/library_fs.js                 |  1 +
 test/other/test_seek_dev_null.c   | 21 +++++++++++++++++++++
 test/other/test_seek_dev_null.out |  2 ++
 test/test_other.py                |  3 +++
 4 files changed, 27 insertions(+)
 create mode 100644 test/other/test_seek_dev_null.c
 create mode 100644 test/other/test_seek_dev_null.out

diff --git a/src/library_fs.js b/src/library_fs.js
index d24cdbf1c7500..886efa61f4c45 100644
--- a/src/library_fs.js
+++ b/src/library_fs.js
@@ -1347,6 +1347,7 @@ FS.staticInit();
       FS.registerDevice(FS.makedev(1, 3), {
         read: () => 0,
         write: (stream, buffer, offset, length, pos) => length,
+        llseek: () => 0,
       });
       FS.mkdev('/dev/null', FS.makedev(1, 3));
       // setup /dev/tty and /dev/tty1
diff --git a/test/other/test_seek_dev_null.c b/test/other/test_seek_dev_null.c
new file mode 100644
index 0000000000000..a72872a17718d
--- /dev/null
+++ b/test/other/test_seek_dev_null.c
@@ -0,0 +1,21 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+#include <stdio.h>
+
+int main() {
+    int fd = open("/dev/null", O_WRONLY);
+    printf("fd: %d\n", fd);
+    if (fd == -1) {
+        printf("open failed: %s\n", strerror(errno));
+        return 1;
+    }
+    int res = lseek(fd, 10, SEEK_CUR);
+    printf("res: %d\n", res);
+    if (res == -1) {
+        printf("lseek failed: %s\n", strerror(errno));
+        return 1;
+    }
+    return 0;
+}
diff --git a/test/other/test_seek_dev_null.out b/test/other/test_seek_dev_null.out
new file mode 100644
index 0000000000000..c9882bbf2b2c4
--- /dev/null
+++ b/test/other/test_seek_dev_null.out
@@ -0,0 +1,2 @@
+fd: 3
+res: 0
diff --git a/test/test_other.py b/test/test_other.py
index 594651b6cb33c..2079fd8d44f2b 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -15329,3 +15329,6 @@ def test_fp16(self, opts):
 
   def test_embool(self):
     self.do_other_test('test_embool.c')
+
+  def test_seek_dev_null(self):
+    self.do_other_test('test_seek_dev_null.c')

From 20b1a3275dcb0754e2be287dbc6ef12c34e8bd23 Mon Sep 17 00:00:00 2001
From: Hood Chatham <roberthoodchatham@gmail.com>
Date: Thu, 14 Nov 2024 12:06:28 +0100
Subject: [PATCH 2/2] Add test to test_files.c

---
 test/other/test_seek_dev_null.c   | 21 ---------------------
 test/other/test_seek_dev_null.out |  2 --
 test/test_files.c                 |  2 ++
 test/test_files.out               |  1 +
 test/test_other.py                |  3 ---
 5 files changed, 3 insertions(+), 26 deletions(-)
 delete mode 100644 test/other/test_seek_dev_null.c
 delete mode 100644 test/other/test_seek_dev_null.out

diff --git a/test/other/test_seek_dev_null.c b/test/other/test_seek_dev_null.c
deleted file mode 100644
index a72872a17718d..0000000000000
--- a/test/other/test_seek_dev_null.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include <unistd.h>
-#include <fcntl.h>
-#include <string.h>
-#include <errno.h>
-#include <stdio.h>
-
-int main() {
-    int fd = open("/dev/null", O_WRONLY);
-    printf("fd: %d\n", fd);
-    if (fd == -1) {
-        printf("open failed: %s\n", strerror(errno));
-        return 1;
-    }
-    int res = lseek(fd, 10, SEEK_CUR);
-    printf("res: %d\n", res);
-    if (res == -1) {
-        printf("lseek failed: %s\n", strerror(errno));
-        return 1;
-    }
-    return 0;
-}
diff --git a/test/other/test_seek_dev_null.out b/test/other/test_seek_dev_null.out
deleted file mode 100644
index c9882bbf2b2c4..0000000000000
--- a/test/other/test_seek_dev_null.out
+++ /dev/null
@@ -1,2 +0,0 @@
-fd: 3
-res: 0
diff --git a/test/test_files.c b/test/test_files.c
index 57c8a4c3a12d2..13d4e7ba95574 100644
--- a/test/test_files.c
+++ b/test/test_files.c
@@ -162,6 +162,8 @@ void test_tempfiles() {
   char data[5] = { 10, 30, 20, 11, 88 };
   FILE *n = fopen("/dev/null", "w");
   printf("5 bytes to dev/null: %zu\n", fwrite(data, 1, 5, n));
+  int res = fseek(n, 10, SEEK_CUR);
+  printf("seek /dev/null: %d\n", res);
   fclose(n);
 
   // Test file creation with O_TRUNC (regression test for #16784)
diff --git a/test/test_files.out b/test/test_files.out
index d8a72d702b275..7b32cdb1c8a38 100644
--- a/test/test_files.out
+++ b/test/test_files.out
@@ -12,4 +12,5 @@ seeked=ata.
 seeked=ta.
 fscanfed: 10 - hello
 5 bytes to dev/null: 5
+seek /dev/null: 0
 ok.
diff --git a/test/test_other.py b/test/test_other.py
index 2079fd8d44f2b..594651b6cb33c 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -15329,6 +15329,3 @@ def test_fp16(self, opts):
 
   def test_embool(self):
     self.do_other_test('test_embool.c')
-
-  def test_seek_dev_null(self):
-    self.do_other_test('test_seek_dev_null.c')