1 files changed, 103 insertions, 0 deletions
diff --git a/unix/os/zfprot.c b/unix/os/zfprot.c
new file mode 100644
index 00000000..edcadbbd
--- /dev/null
+++ b/unix/os/zfprot.c
@@ -0,0 +1,103 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#define	import_kernel
+#define	import_knames
+#define import_protect
+#define import_spp
+#include <iraf.h>
+
+#define	PREFIX		".."		/* hidden link for protected files */
+
+static int chk_prot (char *fname, char *link_name);
+
+
+/* ZFPROT -- Protect a file from accidental deletion.  In UNIX, this is
+ * done by making another link to the file.  If ZFPROT is directed to protect
+ * a file, and the file is already protected, the call is ignored.  Similarly,
+ * if ZFPROT is directed to remove protection, and the file is not protected,
+ * the call is ignored.
+ */
+int
+ZFPROT (
+  PKCHAR  *fname,
+  XINT	  *action, 
+  XINT    *status
+)
+{
+	register char	*p;
+	char	link_name[SZ_PATHNAME];
+	int	first;
+
+
+	/* Build up name of link file: "dir/..fname".  This is done by copying
+	 * fname to the filename buffer of the link file and truncating the
+	 * new filename after the directory prefix (if any).
+	 */
+	strcpy (link_name, (char *)fname);
+	if ((p = strrchr (link_name, '/')) != NULL) {
+	    *(p+1) = EOS;
+	    first = p - link_name + 1;		/* first char after '/' */
+	} else {
+	    *link_name = EOS;
+	    first = 0;
+	}
+
+	strcat (link_name, PREFIX);
+	strcat (link_name, &((char *)fname)[first]);
+
+	if (access ((char *)fname, 0) == ERR)
+	    return ((*status = XERR));
+
+	switch (*action) {
+	case REMOVE_PROTECTION:
+	    if (chk_prot ((char *)fname, link_name) == XNO)
+		*status = XOK;
+	    else if (unlink (link_name) == ERR)
+		*status = XERR;
+	    else 
+		*status = XOK;
+	    return (*status);
+
+	case SET_PROTECTION:
+	    *status = XOK;
+	    if (chk_prot ((char *)fname, link_name) == XNO) {
+		unlink (link_name);
+		if (link ((char *)fname, link_name) == ERR)
+		    *status = XERR;
+	    }
+	    return (*status);
+
+	default:
+	    *status = chk_prot ((char *)fname, link_name);
+	    return (*status);
+	}
+}
+
+
+/* CHK_PROT -- Determine whether or not a file is protected.
+ */
+static int
+chk_prot (char *fname, char *link_name)
+{
+	int	access();
+	struct	stat file1, file2;
+
+	if (access(link_name,0) == ERR)
+	    return (XNO);
+	else {
+	    stat (fname, &file1);
+	    stat (link_name, &file2);
+	    /* Make sure prefixed file is actually a link to original file */
+	    if (file1.st_ino == file2.st_ino && file1.st_dev == file2.st_dev)
+		return (XYES);
+	    else
+		return (XNO);
+	}
+}