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authorFlorian Weimer <fweimer@redhat.com>2019-06-14 16:28:41 +0200
committerFlorian Weimer <fweimer@redhat.com>2019-06-14 16:28:41 +0200
commit48c3c1238925410b4e777dc94e2fde4cc9132d44 (patch)
tree47fe7ff3defaf090e7b6a37302bc1797613b0c59
parent8d141877e07cc594e9fefc3795b8ba729288093c (diff)
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Linux: Fix __glibc_has_include use for <sys/stat.h> and statx
The identifier linux is used as a predefined macro, so the actually
used path is 1/stat.h or 1/stat64.h.  Using the quote-based version
triggers a file lookup for /usr/include/bits/linux/stat.h (or whatever
directory is used to store bits/statx.h), but since bits/ is pretty
much reserved by glibc, this appears to be acceptable.

This is related to GCC PR 80005: incorrect macro expansion of the
argument of __has_include.

Suggested by Zack Weinberg.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
-rw-r--r--ChangeLog5
-rw-r--r--sysdeps/unix/sysv/linux/bits/statx.h7
2 files changed, 10 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index 4aae5e74f7..efd86e05ed 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2019-06-14  Florian Weimer  <fweimer@redhat.com>
 
+	* sysdeps/unix/sysv/linux/bits/statx.h: Use string literal in
+	argument to __glibc_has_include to inhibit macro expansion.
+
+2019-06-14  Florian Weimer  <fweimer@redhat.com>
+
 	* misc/sys/cdefs.h (__glibc_has_include): Do not use a
 	function-like macro, so that __has_include can inhibit expansion
 	of its argument.
diff --git a/sysdeps/unix/sysv/linux/bits/statx.h b/sysdeps/unix/sysv/linux/bits/statx.h
index d36f44efc6..206878723f 100644
--- a/sysdeps/unix/sysv/linux/bits/statx.h
+++ b/sysdeps/unix/sysv/linux/bits/statx.h
@@ -23,8 +23,11 @@
 #endif
 
 /* Use the Linux kernel header if available.  */
-#if __glibc_has_include (<linux/stat.h>)
-# include <linux/stat.h>
+
+/* Use "" to work around incorrect macro expansion of the
+   __has_include argument (GCC PR 80005).  */
+#if __glibc_has_include ("linux/stat.h")
+# include "linux/stat.h"
 # ifdef STATX_TYPE
 #  define __statx_timestamp_defined 1
 #  define __statx_defined 1