Refuse to patch read-only files

* src/patch.c (main): Refuse to patch read-only files, or at least warn
when patching such files with --force or --batch.
* patch.man: Document the changed behavior.
* tests/read-only-files: Split read-only file test case off from
tests/remember-backup-files.
* tests/Makefile.am: Add new test case.

6 files changed, 73 insertions, 30 deletions

diff --git a/ChangeLog b/ChangeLog
index 5b709bc..ee6cc15 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2009-05-02  Andreas Gruenbacher  <agruen@suse.de>
+
+	* src/patch.c (main): Refuse to patch read-only files, or at least warn
+	when patching such files with --force or --batch.
+	* patch.man: Document the changed behavior.
+	* tests/read-only-files: Split read-only file test case off from
+	tests/remember-backup-files.
+	* tests/Makefile.am: Add new test case.
+
 2009-04-29  Andreas Gruenbacher  <agruen@suse.de>
 
 	* src/patch.c (main): Support git diffs which copy or rename files.
diff --git a/patch.man b/patch.man
index 87fe124..02e6b90 100644
--- a/patch.man
+++ b/patch.man
@@ -356,8 +356,8 @@ removes a file, it also attempts to remove any empty ancestor directories.
 \fB\-f\fP  or  \fB\*=force\fP
 Assume that the user knows exactly what he or she is doing, and do not
 ask any questions.  Skip patches whose headers
-do not say which file is to be patched; patch files even though they have the
-wrong version for the
+do not say which file is to be patched; patch files even though they are
+read-only or have the wrong version for the
 .B Prereq:\&
 line in the patch; and assume that
 patches are not reversed even if they look like they are.
diff --git a/src/patch.c b/src/patch.c
index be76f68..1d42d90 100644
--- a/src/patch.c
+++ b/src/patch.c
@@ -229,7 +229,19 @@ main (int argc, char **argv)
 	  skip_rest_of_patch = true;
 	  somefailed = true;
 	}
-
+	if (! inerrno && ! S_ISLNK (instat.st_mode)
+	    && access (inname, W_OK) != 0)
+	  {
+	    say ("File %s is read-only; ", quotearg (inname));
+	    if (force || batch)
+	      say ("trying to patch anyway\n");
+	    else
+	      {
+		say ("refusing to patch\n");
+		skip_rest_of_patch = true;
+		somefailed = true;
+	      }
+	  }
 	/* initialize the patched file */
 	if (! skip_rest_of_patch && ! outfile)
 	  {
@@ -382,7 +394,6 @@ main (int argc, char **argv)
       if (! skip_rest_of_patch && ! outfile) {
 	  bool backup = make_backups
 			|| (backup_if_mismatch && (mismatch | failed));
-
 	  if (outstate.zero_output
 	      && (remove_empty_files
 		  || (pch_says_nonexistent (! reverse) == 2
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3498cc1..39af751 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -37,6 +37,7 @@ TESTS = \
 	preserve-c-function-names \
 	preserve-mode-and-timestamp \
 	quoted-filenames \
+	read-only-files \
 	reject-format \
 	remember-backup-files \
 	remember-reject-files \
diff --git a/tests/read-only-files b/tests/read-only-files
new file mode 100644
index 0000000..816baab
--- /dev/null
+++ b/tests/read-only-files
@@ -0,0 +1,48 @@
+# Copyright (C) 2009 Free Software Foundation, Inc.
+#
+# Copying and distribution of this file, with or without modification,
+# in any medium, are permitted without royalty provided the copyright
+# notice and this notice are preserved.
+
+# Patching read-only files
+
+. $srcdir/test-lib.sh
+
+require_cat
+use_local_patch
+use_tmpdir
+
+# ==============================================================
+
+cat > f.diff <<EOF
+--- f.orig
++++ f
+@@ -1 +1 @@
+-one
++two
+--- f.orig
++++ f
+@@ -1 +1 @@
+-two
++three
+EOF
+
+echo one > f
+chmod a=r f
+
+check 'patch -p0 < f.diff || echo "Status: $?"' <<EOF
+File f is read-only; refusing to patch
+1 out of 1 hunk ignored -- saving rejects to file f.rej
+File f is read-only; refusing to patch
+1 out of 1 hunk ignored -- saving rejects to file f.rej
+Status: 1
+EOF
+
+rm -f f.rej
+
+check 'patch -f -p0 < f.diff || echo "Status: $?"' <<EOF
+File f is read-only; trying to patch anyway
+patching file f
+File f is read-only; trying to patch anyway
+patching file f
+EOF
diff --git a/tests/remember-backup-files b/tests/remember-backup-files
index 86aafa3..b475d2f 100644
--- a/tests/remember-backup-files
+++ b/tests/remember-backup-files
@@ -82,29 +82,3 @@ EOF
 check 'cat g.orig' <<EOF
 one
 EOF
-
-# ==============================================================
-
-# This test case failed with a permission denied error with a
-# previous version of the remember-backup-files patch.
-
-cat > f.diff <<EOF
---- f.orig
-+++ f
-@@ -1 +1 @@
--one
-+two
---- f.orig
-+++ f
-@@ -1 +1 @@
--two
-+three
-EOF
-
-echo one > f
-chmod a=r f
-
-check 'patch -p0 < f.diff' <<EOF
-patching file f
-patching file f
-EOF