Imported Upstream version 93u+upstream

1 files changed, 127 insertions, 0 deletions

diff --git a/src/lib/libcoshell/cosync.c b/src/lib/libcoshell/cosync.c
new file mode 100644
index 0000000..4439efa
--- /dev/null
+++ b/src/lib/libcoshell/cosync.c
@@ -0,0 +1,127 @@
+/***********************************************************************
+*                                                                      *
+*               This software is part of the ast package               *
+*          Copyright (c) 1990-2011 AT&T Intellectual Property          *
+*                      and is licensed under the                       *
+*                 Eclipse Public License, Version 1.0                  *
+*                    by AT&T Intellectual Property                     *
+*                                                                      *
+*                A copy of the License is available at                 *
+*          http://www.eclipse.org/org/documents/epl-v10.html           *
+*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
+*                                                                      *
+*              Information and Software Systems Research               *
+*                            AT&T Research                             *
+*                           Florham Park NJ                            *
+*                                                                      *
+*                 Glenn Fowler <gsf@research.att.com>                  *
+*                                                                      *
+***********************************************************************/
+#pragma prototyped
+/*
+ * Glenn Fowler
+ * AT&T Research
+ *
+ * sync all outstanding file operations for file opened on fd
+ * if file==0 then fd used
+ * if fd<0 then file used
+ * if mode<0 then fd not created
+ *
+ * NOTE: this is an unfortunate NFS workaround that should be done by fsync()
+ */
+
+#include "colib.h"
+
+#include <ls.h>
+
+#include "FEATURE/nfsd"
+
+int
+cosync(Coshell_t* co, const char* file, int fd, int mode)
+{
+#if defined(_cmd_nfsd)
+	if (!co || (co->flags & CO_SERVER))
+	{
+		char	tmp[PATH_MAX];
+
+		if (file && *file)
+		{
+			register const char*	s;
+			register char*		t;
+			register char*		b;
+			int			td;
+
+			/*
+			 * writing to a dir apparently flushes the
+			 * attribute cache for all entries in the dir
+			 */
+
+			s = file;
+			b = t = tmp;
+			while (t < &tmp[sizeof(tmp) - 1])
+			{
+				if (!(*t = *s++)) break;
+				if (*t++ == '/') b = t;
+			}
+			s = "..nfs..botch..";
+			t = b;
+			while (t < &tmp[sizeof(tmp) - 1] && (*t++ = *s++));
+			*t = 0;
+			if ((td = open(tmp, O_WRONLY|O_CREAT|O_TRUNC, 0)) >= 0) close(td);
+			unlink(tmp);
+			if (fd >= 0 && mode >= 0)
+			{
+				if ((td = open(file, mode)) < 0) return(-1);
+				close(fd);
+				dup2(td, fd);
+				close(td);
+			}
+		}
+#if defined(F_SETLK)
+		else
+		{
+			int		clean = 0;
+			struct flock	lock;
+
+			if (fd < 0)
+			{
+				if (!file || mode < 0 || (fd = open(file, O_RDONLY)) < 0) return(-1);
+				clean = 1;
+			}
+
+			/*
+			 * this sets the VNOCACHE flag across NFS
+			 */
+
+			lock.l_type = F_RDLCK;
+			lock.l_whence = 0;
+			lock.l_start = 0;
+			lock.l_len = 1;
+			if (!fcntl(fd, F_SETLK, &lock))
+			{
+				lock.l_type = F_UNLCK;
+				fcntl(fd, F_SETLK, &lock);
+			}
+			if (clean) close(fd);
+
+			/*
+			 * 4.1 has a bug that lets VNOCACHE linger after unlock
+			 * VNOCACHE inhibits mapping which kills exec
+			 * the double rename flushes the incore vnode (and VNOCACHE)
+			 *
+			 * this kind of stuff doesn't happen with *real* file systems
+			 */
+
+			if (file && *file)
+			{
+				strcpy(tmp, file);
+				fd = strlen(tmp) - 1;
+				tmp[fd] = (tmp[fd] == '*') ? '?' : '*';
+				if (!rename(file, tmp)) rename(tmp, file);
+			}
+		}
+#endif
+	}
+#endif
+	return(0);
+}