[Sanitizer] Fix MIPS64 kernel_stat_to_stat()

[mstojanovic]

Summary

This patch takles with two issues:

1. Output stat st_[a|m|c]time fields were holding wrong values. st_[a|m|c]time fields should have contained value of seconds and instead we were filling them with st_[a|m|c]time_nsec fields which hold nanoseconds.

2. Build fails for MIPS64 if SANITIZER_ANDROID. Recently <sys/stat.h> from bionic introduced st_[a|m|c]time_nsec macros for compatibility with old NDKs and those clashed with the field names of the <asm/stat.h> kernel_stat structure.

To fix both issues and make sure sanitizer builds on all platforms
we must un-define all compatibility macros and access the fields
directly when copying the 'time' fields.

Patch submitted by: Miodrag Dinic <[e-mail]>

[sdardis]

lib/sanitizer_common/sanitizer_linux.cc

251–252

What environments define these macros for 'struct stat'?

[miodrag.dinic]

lib/sanitizer_common/sanitizer_linux.cc

251–252

Hi Simon,

sorry for a late response.

These should be coming from glibc:
__USE_XOPEN2K8 : https://github.com/lattera/glibc/blob/master/include/features.h#L261

__USE_MISC : https://github.com/lattera/glibc/blob/master/include/features.h#L305

These guards were introduced a while ago in mips/bits/stat.h :
https://sourceware.org/ml/glibc-cvs/2009-q4/msg00168.html

This is the current state in glibc:
https://github.com/lattera/glibc/blob/master/sysdeps/unix/sysv/linux/bits/stat.h

[sdardis]

llvm-commits should have been added to the subscribers list.

[sdardis]

LGTM.

lib/sanitizer_common/sanitizer_linux.cc

static void stat64_to_stat(struct stat64 *in, struct stat *out) {
   out->st_blocks = in->st_blocks;
   out->st_atime = in->st_atime;
   out->st_mtime = in->st_mtime;
   out->st_ctime = in->st_ctime;
 }
 #endif
 
 #if defined(__mips64)
+// Undefine compatibility macros from <sys/stat.h>
+// so that they would not clash with the kernel_stat
+// st_[a|m|c]time fields
+#undef st_atime
+#undef st_mtime
+#undef st_ctime
+#if defined(SANITIZER_ANDROID)
+// Bionic sys/stat.h defines additional macros
+// for compatibility with the old NDKs and
+// they clash with the kernel_stat structure
+// st_[a|m|c]time_nsec fields.
+#undef st_atime_nsec
+#undef st_mtime_nsec
+#undef st_ctime_nsec
+#endif
 static void kernel_stat_to_stat(struct kernel_stat *in, struct stat *out) {
   internal_memset(out, 0, sizeof(*out));
   out->st_dev = in->st_dev;
   out->st_ino = in->st_ino;
   out->st_mode = in->st_mode;
   out->st_nlink = in->st_nlink;
   out->st_uid = in->st_uid;
   out->st_gid = in->st_gid;
   out->st_rdev = in->st_rdev;
   out->st_size = in->st_size;
   out->st_blksize = in->st_blksize;
   out->st_blocks = in->st_blocks;
-  out->st_atime = in->st_atime_nsec;
-  out->st_mtime = in->st_mtime_nsec;
-  out->st_ctime = in->st_ctime_nsec;
+#if defined(__USE_MISC)     || \
+    defined(__USE_XOPEN2K8) || \
+    defined(SANITIZER_ANDROID)
+  out->st_atim.tv_sec = in->st_atime;
+  out->st_atim.tv_nsec = in->st_atime_nsec;
+  out->st_mtim.tv_sec = in->st_mtime;
+  out->st_mtim.tv_nsec = in->st_mtime_nsec;
+  out->st_ctim.tv_sec = in->st_ctime;
+  out->st_ctim.tv_nsec = in->st_ctime_nsec;
+#else
+  out->st_atime = in->st_atime;
+  out->st_atimensec = in->st_atime_nsec;
+  out->st_mtime = in->st_mtime;
+  out->st_mtimensec = in->st_mtime_nsec;
+  out->st_ctime = in->st_ctime;
+  out->st_atimensec = in->st_ctime_nsec;
+#endif
 }
 #endif
 
 uptr internal_stat(const char *path, void *buf) {
 #if SANITIZER_FREEBSD
   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path,
                           (uptr)buf, 0);
 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS