commit 22917f63ee9ff25f629167b4a54f7d8be37da505
author Elliott Hughes <enh@google.com> Mon Oct 01 14:21:07 2018 -0700
committer Elliott Hughes <enh@google.com> Mon Oct 01 16:17:37 2018 -0700
tree a44ac1fae0dc4cc1f405096ef6cfd6e981afd5db
parent 7208139406adbd40782ccd7554e1a21458da2b37

Make fclose/pclose distinct.

I failed to convince the compiler/linker to just refrain (via factoring out,
attribute `noinline`, or meddling with `--icf=none`), but luckily I noticed
that we should have CHECK_FP in each function for a better error message,
and the distinct error messages keep the two functions apart.

(Also add a missing CHECK_FP to `clearerr_unlocked`.)

Bug: http://b/116969207
Test: manual with a modified `crasher`
Change-Id: Ic122e90e94f7e22f486be57d3dac7137a225d682

libc/stdio/stdio.cpp

diff --git a/libc/stdio/stdio.cpp b/libc/stdio/stdio.cpp
index 71fdd27..d7b69dc 100644
--- a/libc/stdio/stdio.cpp
+++ b/libc/stdio/stdio.cpp
@@ -404,8 +404,7 @@
 }
 __strong_alias(freopen64, freopen);
 
-int fclose(FILE* fp) {
-  CHECK_FP(fp);
+static int __FILE_close(FILE* fp) {
   if (fp->_flags == 0) {
     // Already freed!
     errno = EBADF;
@@ -440,7 +439,11 @@
   fp->_flags = 0;
   return r;
 }
-__strong_alias(pclose, fclose);
+
+int fclose(FILE* fp) {
+  CHECK_FP(fp);
+  return __FILE_close(fp);
+}
 
 int fileno_unlocked(FILE* fp) {
   CHECK_FP(fp);
@@ -459,6 +462,7 @@
 }
 
 void clearerr_unlocked(FILE* fp) {
+  CHECK_FP(fp);
   return __sclearerr(fp);
 }
 
@@ -1235,6 +1239,11 @@
   return fp;
 }
 
+int pclose(FILE* fp) {
+  CHECK_FP(fp);
+  return __FILE_close(fp);
+}
+
 namespace {
 
 namespace phony {