[libc-commits] [libc] [libc] Fix readlink tests on 32-bit systems (PR #97850)

[Mikhail R. Gadelha via libc-commits]

https://github.com/mikhailramalho created https://github.com/llvm/llvm-project/pull/97850

Use sizeof in a string literal instead of a CString so we get the right size when creating the buf array.

We also now use strlen(FILENAME) to get the string lenght when calling readlink and readlinkat.

>From 66113a16bb712bf451bdc1d1939604bd3fc84ce6 Mon Sep 17 00:00:00 2001
From: "Mikhail R. Gadelha" <mikhail at igalia.com>
Date: Fri, 5 Jul 2024 14:37:42 -0300
Subject: [PATCH] [libc] Fix readlink tests on 32-bit systems

Use sizeof in a string literal instead of a CString so we get the right
size when creating the buf array.

We also now use strlen(FILENAME) to get the string lenght when calling
readlink and readlinkat.
---
 libc/test/src/unistd/CMakeLists.txt      |  2 ++
 libc/test/src/unistd/readlink_test.cpp   | 11 +++++++----
 libc/test/src/unistd/readlinkat_test.cpp | 15 +++++++++------
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/libc/test/src/unistd/CMakeLists.txt b/libc/test/src/unistd/CMakeLists.txt
index de3e8d9ccbb62..b311bbf59bbca 100644
--- a/libc/test/src/unistd/CMakeLists.txt
+++ b/libc/test/src/unistd/CMakeLists.txt
@@ -262,6 +262,7 @@ add_libc_unittest(
     libc.include.unistd
     libc.src.errno.errno
     libc.src.unistd.readlink
+    libc.src.string.strlen
     libc.src.unistd.symlink
     libc.src.unistd.unlink
     libc.src.__support.CPP.string_view
@@ -279,6 +280,7 @@ add_libc_unittest(
     libc.include.unistd
     libc.src.errno.errno
     libc.src.unistd.readlinkat
+    libc.src.string.strlen
     libc.src.unistd.symlink
     libc.src.unistd.unlink
     libc.src.__support.CPP.string_view
diff --git a/libc/test/src/unistd/readlink_test.cpp b/libc/test/src/unistd/readlink_test.cpp
index 20f3951349118..cd2a36ed86b11 100644
--- a/libc/test/src/unistd/readlink_test.cpp
+++ b/libc/test/src/unistd/readlink_test.cpp
@@ -8,6 +8,7 @@
 
 #include "src/__support/CPP/string_view.h"
 #include "src/errno/libc_errno.h"
+#include "src/string/strlen.h"
 #include "src/unistd/readlink.h"
 #include "src/unistd/symlink.h"
 #include "src/unistd/unlink.h"
@@ -30,8 +31,9 @@ TEST(LlvmLibcReadlinkTest, CreateAndUnlink) {
   //   3. Cleanup the symlink created in step #1.
   ASSERT_THAT(LIBC_NAMESPACE::symlink(LINK_VAL, LINK), Succeeds(0));
 
-  char buf[sizeof(LINK_VAL)];
-  ssize_t len = LIBC_NAMESPACE::readlink(LINK, buf, sizeof(buf));
+  char buf[sizeof(FILENAME)];
+  ssize_t len =
+      LIBC_NAMESPACE::readlink(LINK, buf, LIBC_NAMESPACE::strlen(FILENAME));
   ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(cpp::string_view(buf, len), cpp::string_view(LINK_VAL));
 
@@ -40,7 +42,8 @@ TEST(LlvmLibcReadlinkTest, CreateAndUnlink) {
 
 TEST(LlvmLibcReadlinkTest, ReadlinkInNonExistentPath) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
-  char buf[8];
-  ASSERT_THAT(LIBC_NAMESPACE::readlink("non-existent-link", buf, sizeof(buf)),
+  constexpr auto len = 8;
+  char buf[len];
+  ASSERT_THAT(LIBC_NAMESPACE::readlink("non-existent-link", buf, len),
               Fails(ENOENT));
 }
diff --git a/libc/test/src/unistd/readlinkat_test.cpp b/libc/test/src/unistd/readlinkat_test.cpp
index 39d81d9ba544a..33c6c8968b143 100644
--- a/libc/test/src/unistd/readlinkat_test.cpp
+++ b/libc/test/src/unistd/readlinkat_test.cpp
@@ -8,6 +8,7 @@
 
 #include "src/__support/CPP/string_view.h"
 #include "src/errno/libc_errno.h"
+#include "src/string/strlen.h"
 #include "src/unistd/readlinkat.h"
 #include "src/unistd/symlink.h"
 #include "src/unistd/unlink.h"
@@ -32,8 +33,9 @@ TEST(LlvmLibcReadlinkatTest, CreateAndUnlink) {
   //   3. Cleanup the symlink created in step #1.
   ASSERT_THAT(LIBC_NAMESPACE::symlink(LINK_VAL, LINK), Succeeds(0));
 
-  char buf[sizeof(LINK_VAL)];
-  ssize_t len = LIBC_NAMESPACE::readlinkat(AT_FDCWD, LINK, buf, sizeof(buf));
+  char buf[sizeof(FILENAME)];
+  ssize_t len = LIBC_NAMESPACE::readlinkat(AT_FDCWD, LINK, buf,
+                                           LIBC_NAMESPACE::strlen(FILENAME));
   ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(cpp::string_view(buf, len), cpp::string_view(LINK_VAL));
 
@@ -42,8 +44,9 @@ TEST(LlvmLibcReadlinkatTest, CreateAndUnlink) {
 
 TEST(LlvmLibcReadlinkatTest, ReadlinkInNonExistentPath) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
-  char buf[8];
-  ASSERT_THAT(LIBC_NAMESPACE::readlinkat(AT_FDCWD, "non-existent-link", buf,
-                                         sizeof(buf)),
-              Fails(ENOENT));
+  constexpr auto len = 8;
+  char buf[len];
+  ASSERT_THAT(
+      LIBC_NAMESPACE::readlinkat(AT_FDCWD, "non-existent-link", buf, len),
+      Fails(ENOENT));
 }