don't warn twice about the same invalid file name

* src/pch.c (name_is_valid): Don't warn about the same name twice.
* tests/bad-filenames (emit_patch): Exercise the new code.

3 files changed, 40 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index defc7be..046df0e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-02-17  Jim Meyering  <meyering@redhat.com>
+	and Andreas Gruenbacher <agruen@linbit.com>
+
+	don't warn twice about the same invalid file name
+	* src/pch.c (name_is_valid): Don't warn about the same name twice.
+	* tests/bad-filenames (emit_patch): Exercise the new code.
+
 2011-02-16  Andreas Gruenbacher <agruen@linbit.com>
 
 	* src/pch.c (name_is_valid): New function.
diff --git a/src/pch.c b/src/pch.c
index 41c15b6..1fd3848 100644
--- a/src/pch.c
+++ b/src/pch.c
@@ -379,11 +379,18 @@ skip_hex_digits (char const *str)
 static bool
 name_is_valid (char const *name)
 {
-  const char *n = name;
+  static char const *bad[2];
+  char const *n;
+
+  if (bad[0] && ! strcmp (bad[0], name))
+    return false;
+  if (bad[1] && ! strcmp (bad[1], name))
+    return false;
 
   if (IS_ABSOLUTE_FILE_NAME (name))
     {
       say ("Ignoring potentially dangerous file name %s\n", quotearg (name));
+      bad[!! bad[0]] = name;
       return false;
     }
   for (n = name; *n; )
@@ -391,6 +398,7 @@ name_is_valid (char const *name)
       if (*n == '.' && *++n == '.' && ( ! *++n || ISSLASH (*n)))
         {
 	  say ("Ignoring potentially dangerous file name %s\n", quotearg (name));
+	  bad[!! bad[0]] = name;
 	  return false;
 	}
       while (*n && ! ISSLASH (*n))
diff --git a/tests/bad-filenames b/tests/bad-filenames
index 0bc23eb..e1b9e92 100644
--- a/tests/bad-filenames
+++ b/tests/bad-filenames
@@ -114,3 +114,27 @@ echo 1 > g
 check 'patch -f -p1 --dry-run < d.diff || echo status: $?' <<EOF
 patching file g
 EOF
+
+mkdir d
+cd d
+cat > d.diff <<EOF
+--- ../h
++++ ../h
+@@ -0,0 +1 @@
++x
+EOF
+
+touch ../h
+check 'patch -f -p0 < d.diff || echo status: $?' <<EOF
+Ignoring potentially dangerous file name ../h
+can't find file to patch at input line 3
+Perhaps you used the wrong -p or --strip option?
+The text leading up to this was:
+--------------------------
+|--- ../h
+|+++ ../h
+--------------------------
+No file to patch.  Skipping patch.
+1 out of 1 hunk ignored
+status: 1
+EOF