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[PATCH v2 2/2] check-ignore.c, dir.c: fix segfault with '.' argument from repo root

From
Adam Spiers <git@adamspiers.org>
Date
Feb 19, 2013, 19:21 UTC
Message-ID
<1361301696-11307-1-git-send-email-git@adamspiers.org>
In-Reply-To
<CAOkDyE9VVuFn6B=Fe4XHxGCEW0MFgndx1X0+9hO36Soxb37YQw@mail.gmail.com>

Fix a corner case where check-ignore would segfault when run with the '.' argument from the top level of a repository, due to prefix_path() converting '.' into the empty string. It doesn't make much sense to call check-ignore from the top level with '.' as a parameter, since the top-level directory would never typically be ignored, but of course it should not segfault in this case. The existing code attempted to check for this case but failed due to using the wrong variable. Instead we move the check to last_exclude_matching_path(), in case other callers present or future have a similar issue.

Signed-off-by: Adam Spiers <git@adamspiers.org>
---
 builtin/check-ignore.c | 2 +-
 dir.c                  | 8 ++++++++
 t/t0008-ignores.sh     | 5 +++++
 3 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/builtin/check-ignore.c b/builtin/check-ignore.c
index 709535c..0240f99 100644
--- a/builtin/check-ignore.c
+++ b/builtin/check-ignore.c
@@ -89,7 +89,7 @@ static int check_ignore(const char *prefix, const char **pathspec)
 					? strlen(prefix) : 0, path);
 		full_path = check_path_for_gitlink(full_path);
 		die_if_path_beyond_symlink(full_path, prefix);
-		if (!seen[i] && path[0]) {
+		if (!seen[i]) {
 			exclude = last_exclude_matching_path(&check, full_path,
 							     -1, &dtype);
 			if (exclude) {
diff --git a/dir.c b/dir.c
index 57394e4..1ae0b90 100644
--- a/dir.c
+++ b/dir.c
@@ -828,6 +828,14 @@ struct exclude *last_exclude_matching_path(struct path_exclude_check *check,
 	struct exclude *exclude;
 
 	/*
+	 * name could be the empty string, e.g. if check-ignore was
+	 * invoked from the top level with '.', prefix_path() will
+	 * convert it into "".
+	 */
+	if (!*name)
+		return NULL;
+
+	/*
 	 * we allow the caller to pass namelen as an optimization; it
 	 * must match the length of the name, as we eventually call
 	 * is_excluded() on the whole name string.
diff --git a/t/t0008-ignores.sh b/t/t0008-ignores.sh
index ebe7c70..9c1bde1 100755
--- a/t/t0008-ignores.sh
+++ b/t/t0008-ignores.sh
@@ -138,6 +138,7 @@ test_expect_success 'setup' '
 	cat <<-\EOF >.gitignore &&
 		one
 		ignored-*
+		top-level-dir/
 	EOF
 	for dir in . a
 	do
@@ -177,6 +178,10 @@ test_expect_success 'setup' '
 #
 # test invalid inputs
 
+test_expect_success_multi '. corner-case' '' '
+	test_check_ignore . 1
+'
+
 test_expect_success_multi 'empty command line' '' '
 	test_check_ignore "" 128 &&
 	stderr_contains "fatal: no path specified"
-- 
1.8.2.rc0.18.g543d1e4
Previous: Adam SpiersNext: Junio C Hamano
Message 7 of 27 in “[BUG] git-check-ignore: Segmentation fault”
  1. Zoltan KlingerFeb 19, 2013
  2. Adam SpiersFeb 19, 2013
  3. 1/2 t0008: document test_expect_success_multiAdam Spiers, Feb 19, 2013
  4. 2/2 check-ignore.c: fix segfault with '.' argument from repo rootAdam Spiers, Feb 19, 2013
  5. Junio C HamanoFeb 19, 2013
  6. Adam SpiersFeb 19, 2013
  7. 2/2 check-ignore.c, dir.c: fix segfault with '.' argument from repo rootAdam Spiers, Feb 19, 2013
  8. Junio C HamanoFeb 19, 2013
  9. Junio C HamanoFeb 19, 2013
  10. Adam SpiersFeb 20, 2013
  11. Junio C HamanoFeb 20, 2013
  12. Adam SpiersFeb 20, 2013
  13. Adam SpiersFeb 20, 2013
  14. Re* [PATCH 2/2] check-ignore.c: fix segfault with '.' argument from repo rootJunio C Hamano, Feb 19, 2013
  15. Adam SpiersFeb 20, 2013
  16. Junio C HamanoFeb 20, 2013
  17. Adam SpiersFeb 20, 2013
  18. Junio C HamanoFeb 21, 2013
  19. 1/2 format-patch: rename "no_inline" fieldJunio C Hamano, Feb 21, 2013
  20. 2/2 format-patch: --inline-singleJunio C Hamano, Feb 21, 2013
  21. Jeff KingFeb 21, 2013
  22. Junio C HamanoFeb 21, 2013
  23. Junio C HamanoFeb 21, 2013
  24. Adam SpiersFeb 22, 2013
  25. Junio C HamanoFeb 22, 2013
  26. Jeff KingFeb 22, 2013
  27. Junio C HamanoFeb 19, 2013

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