stat: work around Solaris bug with tv_nsec < 0

* doc/posix-functions/fstat.texi (fstat):
* doc/posix-functions/fstatat.texi (fstatat):
* doc/posix-functions/lstat.texi (lstat):
* doc/posix-functions/stat.texi (stat):
Mention Solaris 11 bug.
* lib/fstat.c, lib/fstatat.c, lib/lstat.c: Include stat-time.h.
* lib/fstat.c (rpl_fstat) [!WINDOWS_NATIVE]:
* lib/lstat.c (rpl_lstat):
* lib/stat.c (rpl_stat):
Normalize resulting timestamps.
* lib/fstatat.c (normal_fstatat): New function.
(rpl_fstatat): Use it.
* lib/stat-time.h: Include intprops.h, errno.h, stddef.h.
(stat_time_normalize): New function.
* m4/fstat.m4 (gl_FUNC_FSTAT):
* m4/fstatat.m4 (gl_FUNC_FSTATAT):
* m4/lstat.m4 (gl_FUNC_LSTAT):
* m4/stat.m4 (gl_FUNC_STAT):
Replace on Solaris.
* modules/fstat (Depends-on):
* modules/fstatat (Depends-on):
Add stat-time.
* modules/stat-time (Depends-on): Add errno, intprops.

1 files changed, 45 insertions, 0 deletions

diff --git a/lib/stat-time.h b/lib/stat-time.h
index 47a3bf8f21..1cf821992e 100644
--- a/lib/stat-time.h
+++ b/lib/stat-time.h
@@ -20,6 +20,10 @@
 #ifndef STAT_TIME_H
 #define STAT_TIME_H 1
 
+#include "intprops.h"
+
+#include <errno.h>
+#include <stddef.h>
 #include <sys/stat.h>
 #include <time.h>
 
@@ -202,6 +206,47 @@ get_stat_birthtime (struct stat const *st)
   return t;
 }
 
+/* If a stat-like function returned RESULT, normalize the timestamps
+   in *ST, in case this platform suffers from the Solaris 11 bug where
+   tv_nsec might be negative.  Return the adjusted RESULT, setting
+   errno to EOVERFLOW if normalization overflowed.  This function
+   is intended to be private to this .h file.  */
+_GL_STAT_TIME_INLINE int
+stat_time_normalize (int result, struct stat *st)
+{
+#if defined __sun && defined STAT_TIMESPEC
+  if (result == 0)
+    {
+      long int timespec_resolution = 1000000000;
+      short int const ts_off[] = { offsetof (struct stat, st_atim),
+                                   offsetof (struct stat, st_mtim),
+                                   offsetof (struct stat, st_ctim) };
+      int i;
+      for (i = 0; i < sizeof ts_off / sizeof *ts_off; i++)
+        {
+          struct timespec *ts = (struct timespec *) ((char *) st + ts_off[i]);
+          long int q = ts->tv_nsec / timespec_resolution;
+          long int r = ts->tv_nsec % timespec_resolution;
+          if (r < 0)
+            {
+              r += timespec_resolution;
+              q--;
+            }
+          ts->tv_nsec = r;
+          /* Overflow is possible, as Solaris 11 stat can yield
+             tv_sec == TYPE_MINIMUM (time_t) && tv_nsec == -1000000000.
+             INT_ADD_WRAPV is OK, since time_t is signed on Solaris.  */
+          if (INT_ADD_WRAPV (q, ts->tv_sec, &ts->tv_sec))
+            {
+              errno = EOVERFLOW;
+              return -1;
+            }
+        }
+    }
+#endif
+  return result;
+}
+
 #ifdef __cplusplus
 }
 #endif