Sync with 2.42.2

* maint-2.42: (39 commits)
  Git 2.42.2
  Git 2.41.1
  Git 2.40.2
  Git 2.39.4
  fsck: warn about symlink pointing inside a gitdir
  core.hooksPath: add some protection while cloning
  init.templateDir: consider this config setting protected
  clone: prevent hooks from running during a clone
  Add a helper function to compare file contents
  init: refactor the template directory discovery into its own function
  find_hook(): refactor the `STRIP_EXTENSION` logic
  clone: when symbolic links collide with directories, keep the latter
  entry: report more colliding paths
  t5510: verify that D/F confusion cannot lead to an RCE
  submodule: require the submodule path to contain directories only
  clone_submodule: avoid using `access()` on directories
  submodules: submodule paths must not contain symlinks
  clone: prevent clashing git dirs when cloning submodule in parallel
  t7423: add tests for symlinked submodule directories
  has_dir_name(): do not get confused by characters < '/'
  ...

1 files changed, 61 insertions, 0 deletions

diff --git a/copy.c b/copy.c
index 23d84c6c1d..3df156f6ce 100644
--- a/copy.c
+++ b/copy.c
@@ -1,6 +1,9 @@
 #include "git-compat-util.h"
 #include "copy.h"
 #include "path.h"
+#include "gettext.h"
+#include "strbuf.h"
+#include "abspath.h"
 
 int copy_fd(int ifd, int ofd)
 {
@@ -67,3 +70,61 @@ int copy_file_with_time(const char *dst, const char *src, int mode)
 		return copy_times(dst, src);
 	return status;
 }
+
+static int do_symlinks_match(const char *path1, const char *path2)
+{
+	struct strbuf buf1 = STRBUF_INIT, buf2 = STRBUF_INIT;
+	int ret = 0;
+
+	if (!strbuf_readlink(&buf1, path1, 0) &&
+	    !strbuf_readlink(&buf2, path2, 0))
+		ret = !strcmp(buf1.buf, buf2.buf);
+
+	strbuf_release(&buf1);
+	strbuf_release(&buf2);
+	return ret;
+}
+
+int do_files_match(const char *path1, const char *path2)
+{
+	struct stat st1, st2;
+	int fd1 = -1, fd2 = -1, ret = 1;
+	char buf1[8192], buf2[8192];
+
+	if ((fd1 = open_nofollow(path1, O_RDONLY)) < 0 ||
+	    fstat(fd1, &st1) || !S_ISREG(st1.st_mode)) {
+		if (fd1 < 0 && errno == ELOOP)
+			/* maybe this is a symbolic link? */
+			return do_symlinks_match(path1, path2);
+		ret = 0;
+	} else if ((fd2 = open_nofollow(path2, O_RDONLY)) < 0 ||
+		   fstat(fd2, &st2) || !S_ISREG(st2.st_mode)) {
+		ret = 0;
+	}
+
+	if (ret)
+		/* to match, neither must be executable, or both */
+		ret = !(st1.st_mode & 0111) == !(st2.st_mode & 0111);
+
+	if (ret)
+		ret = st1.st_size == st2.st_size;
+
+	while (ret) {
+		ssize_t len1 = read_in_full(fd1, buf1, sizeof(buf1));
+		ssize_t len2 = read_in_full(fd2, buf2, sizeof(buf2));
+
+		if (len1 < 0 || len2 < 0 || len1 != len2)
+			ret = 0; /* read error or different file size */
+		else if (!len1) /* len2 is also 0; hit EOF on both */
+			break; /* ret is still true */
+		else
+			ret = !memcmp(buf1, buf2, len1);
+	}
+
+	if (fd1 >= 0)
+		close(fd1);
+	if (fd2 >= 0)
+		close(fd2);
+
+	return ret;
+}