Add a minimal implementation of utimensat().

Some systems (eg older OS X) do not have utimensat, so provide minimal
implementation in compat layer.  Fixes build on at least El Capitan.

5 files changed, 144 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index c1427247e..2d1dafdee 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1812,6 +1812,7 @@ AC_CHECK_FUNCS([ \
         truncate \
         unsetenv \
         updwtmpx \
+        utimensat \
         user_from_uid \
         usleep \
         vasprintf \
diff --git a/openbsd-compat/bsd-misc.c b/openbsd-compat/bsd-misc.c
index 5d7540a70..4bae96548 100644
--- a/openbsd-compat/bsd-misc.c
+++ b/openbsd-compat/bsd-misc.c
@@ -25,6 +25,7 @@
 # include <sys/time.h>
 #endif
 
+#include <fcntl.h>
 #include <string.h>
 #include <signal.h>
 #include <stdlib.h>
@@ -117,6 +118,42 @@ int utimes(char *filename, struct timeval *tvp)
 }
 #endif
 
+#ifndef HAVE_UTIMENSAT
+/*
+ * A limited implementation of utimensat() that only implements the
+ * functionality used by OpenSSH, currently only AT_FDCWD and
+ * AT_SYMLINK_NOFOLLOW.
+ */
+int
+utimensat(int fd, const char *path, const struct timespec times[2],
+    int flag)
+{
+        struct timeval tv[2];
+        int ret, oflags = O_WRONLY;
+
+        tv[0].tv_sec = times[0].tv_sec;
+        tv[0].tv_usec = times[0].tv_nsec / 1000;
+        tv[1].tv_sec = times[1].tv_sec;
+        tv[1].tv_usec = times[1].tv_nsec / 1000;
+
+        if (fd != AT_FDCWD) {
+                errno = ENOSYS;
+                return -1;
+        }
+# ifndef HAVE_FUTIMES
+        return utimes(path, tv);
+# else
+        if (flag & AT_SYMLINK_NOFOLLOW)
+                oflags |= O_NOFOLLOW;
+        if ((fd = open(path, oflags)) == -1)
+                return -1;
+        ret = futimes(fd, tv);
+        close(fd);
+        return ret;
+# endif
+}
+#endif
+
 #ifndef HAVE_TRUNCATE
 int truncate(const char *path, off_t length)
 {
diff --git a/openbsd-compat/bsd-misc.h b/openbsd-compat/bsd-misc.h
index 52ec52853..584c2b5ef 100644
--- a/openbsd-compat/bsd-misc.h
+++ b/openbsd-compat/bsd-misc.h
@@ -64,6 +64,14 @@ struct timeval {
 int utimes(char *, struct timeval *);
 #endif /* HAVE_UTIMES */
 
+#ifndef HAVE_UTIMENSAT
+/* start with the high bits and work down to minimise risk of overlap */
+# ifndef AT_SYMLINK_NOFOLLOW
+#  define AT_SYMLINK_NOFOLLOW 0x80000000
+# endif
+int utimensat(int, const char *, const struct timespec[2], int);
+#endif
+
 #ifndef HAVE_TRUNCATE
 int truncate (const char *, off_t);
 #endif /* HAVE_TRUNCATE */
diff --git a/openbsd-compat/regress/Makefile.in b/openbsd-compat/regress/Makefile.in
index 529331be5..c5aae61e2 100644
--- a/openbsd-compat/regress/Makefile.in
+++ b/openbsd-compat/regress/Makefile.in
@@ -14,7 +14,7 @@ LIBS=@LIBS@
 LDFLAGS=@LDFLAGS@ $(LIBCOMPAT)
 
 TESTPROGS=closefromtest$(EXEEXT) snprintftest$(EXEEXT) strduptest$(EXEEXT) \
-        strtonumtest$(EXEEXT) opensslvertest$(EXEEXT)
+        strtonumtest$(EXEEXT) opensslvertest$(EXEEXT) utimensattest$(EXEEXT)
 
 all:    t-exec ${OTHERTESTS}
 
diff --git a/openbsd-compat/regress/utimensattest.c b/openbsd-compat/regress/utimensattest.c
new file mode 100644
index 000000000..a7bc7634b
--- /dev/null
+++ b/openbsd-compat/regress/utimensattest.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2019 Darren Tucker
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define TMPFILE "utimensat.tmp"
+#define TMPFILE2 "utimensat.tmp2"
+
+#ifndef AT_SYMLINK_NOFOLLOW
+# define AT_SYMLINK_NOFOLLOW 0x80000000
+#endif
+
+int utimensat(int, const char *, const struct timespec[2], int);
+
+void
+fail(char *msg, long expect, long got)
+{
+        int saved_errno = errno;
+
+        if (expect == got && got == 0)
+                fprintf(stderr, "utimensat: %s: %s\n", msg,
+                     strerror(saved_errno));
+        else
+                fprintf(stderr, "utimensat: %s: expected %ld got %ld\n",
+                     msg, expect, got);
+        exit(1);
+}
+
+int
+main(void)
+{
+        int fd;
+        struct stat sb;
+        struct timespec ts[2];
+
+        if ((fd = open(TMPFILE, O_CREAT, 0600)) == -1)
+                fail("open", 0, 0);
+        close(fd);
+
+        ts[0].tv_sec = 12345678;
+        ts[0].tv_nsec = 23456789;
+        ts[1].tv_sec = 34567890;
+        ts[1].tv_nsec = 45678901;
+        if (utimensat(AT_FDCWD, TMPFILE, ts, AT_SYMLINK_NOFOLLOW) == -1)
+                fail("utimensat", 0, 0);
+
+        if (stat(TMPFILE, &sb) == -1)
+                fail("stat", 0, 0 );
+        if (sb.st_atime != 12345678)
+                fail("st_atime", 0, 0 );
+        if (sb.st_mtime != 34567890)
+                fail("st_mtime", 0, 0 );
+#if 0
+        /*
+         * Results expected to be rounded to the nearest microsecond.
+         * Depends on timestamp precision in kernel and filesystem so
+         * disabled by default.
+         */
+        if (sb.st_atim.tv_nsec != 23456000)
+                fail("atim.tv_nsec", 23456000, sb.st_atim.tv_nsec);
+        if (sb.st_mtim.tv_nsec != 45678000)
+                fail("mtim.tv_nsec", 45678000, sb.st_mtim.tv_nsec);
+#endif
+
+        if (rename(TMPFILE, TMPFILE2) == -1)
+                fail("rename", 0, 0);
+        if (symlink(TMPFILE2, TMPFILE) == -1)
+                fail("symlink", 0, 0);
+
+        if (utimensat(AT_FDCWD, TMPFILE, ts, AT_SYMLINK_NOFOLLOW) != -1)
+                fail("utimensat followed symlink", 0, 0);
+
+        if (!(unlink(TMPFILE) == 0 && unlink(TMPFILE2) == 0))
+                fail("unlink", 0, 0);
+        exit(0);
+}