commit 25af17c5873292cff4b26eda9f17f6a6870f9a92
author Elliott Hughes <enh@google.com> Wed Oct 11 23:02:37 2023 +0000
committer Elliott Hughes <enh@google.com> Thu Oct 12 16:04:14 2023 +0000
tree 8b73d65bf6d74391e55bf2ce40c036c4f76d7890
parent f89da9b9964c3560b3073f96770a424fbab265cf

Clarify the fcntl() "that's not how F_SETFD works" error.

The first app developer (we know of) that hit this didn't understand
what it was trying to tell them.

Before:
    FORTIFY: fcntl(F_SETFD) passed non-FD_CLOEXEC flag: 0x801

After:
    FORTIFY: fcntl(F_SETFD) only supports FD_CLOEXEC but was passed 0x801

Bug: https://issuetracker.google.com/304348746
Test: treehugger
Change-Id: I8522e851d8f74c91152ebae68b083b5272d49255

libc/bionic/fcntl.cpp

diff --git a/libc/bionic/fcntl.cpp b/libc/bionic/fcntl.cpp
index 754277b..7730a15 100644
--- a/libc/bionic/fcntl.cpp
+++ b/libc/bionic/fcntl.cpp
@@ -44,7 +44,7 @@
   va_end(args);
 
   if (cmd == F_SETFD && (reinterpret_cast<uintptr_t>(arg) & ~FD_CLOEXEC) != 0) {
-    __fortify_fatal("fcntl(F_SETFD) passed non-FD_CLOEXEC flag: %p", arg);
+    __fortify_fatal("fcntl(F_SETFD) only supports FD_CLOEXEC but was passed %p", arg);
   }
 
 #if defined(__LP64__)

tests/fcntl_test.cpp

diff --git a/tests/fcntl_test.cpp b/tests/fcntl_test.cpp
index b3be18e..47f3d91 100644
--- a/tests/fcntl_test.cpp
+++ b/tests/fcntl_test.cpp
@@ -363,5 +363,5 @@
 }
 
 TEST_F(fcntl_DeathTest, fcntl_F_SETFD) {
-  EXPECT_DEATH(fcntl(0, F_SETFD, O_NONBLOCK), "non-FD_CLOEXEC");
+  EXPECT_DEATH(fcntl(0, F_SETFD, O_NONBLOCK), "only supports FD_CLOEXEC");
 }