[PATCH 7/7] kvmtool: 9p: refactor rel_to_abs()

["G. Campana" <gcampana+kvm@xxxxxxxxxxxxx>]

---
 virtio/9p.c | 50 +++++++++++++++++++++++++-------------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/virtio/9p.c b/virtio/9p.c
index 5b2d261..3259b79 100644
--- a/virtio/9p.c
+++ b/virtio/9p.c
@@ -91,18 +91,6 @@ static struct p9_fid *get_fid(struct p9_dev *p9dev, int fid)
 	return new;
 }
 
-static int rel_to_abs(struct p9_dev *p9dev, const char *path, char *abs_path,
-		      size_t size)
-{
-	int ret;
-
-	ret = snprintf(abs_path, size, "%s/%s", p9dev->root_dir, path);
-	if (ret >= (int)size)
-		return -1;
-
-	return 0;
-}
-
 static void stat2qid(struct stat *st, struct p9_qid *qid)
 {
 	*qid = (struct p9_qid) {
@@ -266,6 +254,28 @@ static int get_full_path(char *full_path, size_t size, struct p9_fid *fid,
 	return 0;
 }
 
+static int stat_rel(struct p9_dev *p9dev, const char *path, struct stat *st)
+{
+	int ret;
+	char full_path[PATH_MAX];
+
+	ret = snprintf(full_path, sizeof(full_path), "%s/%s", p9dev->root_dir, path);
+	if (ret >= (int)sizeof(full_path)) {
+		errno = ENAMETOOLONG;
+		return -1;
+	}
+
+	if (path_is_illegal(full_path)) {
+		errno = EACCES;
+		return -1;
+	}
+
+	if (lstat(full_path, st) != 0)
+		return -1;
+
+	return 0;
+}
+
 static void virtio_p9_open(struct p9_dev *p9dev,
 			   struct p9_pdu *pdu, u32 *outlen)
 {
@@ -440,7 +450,6 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
 		for (i = 0; i < nwname; i++) {
 			struct stat st;
 			char tmp[PATH_MAX] = {0};
-			char full_path[PATH_MAX];
 			char *str;
 			int ret;
 
@@ -455,12 +464,7 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
 
 			free(str);
 
-			if (rel_to_abs(p9dev, tmp, full_path, sizeof(full_path)) != 0) {
-				errno = ENAMETOOLONG;
-				goto err_out;
-			}
-
-			if (lstat(full_path, &st) < 0)
+			if (stat_rel(p9dev, tmp, &st) != 0)
 				goto err_out;
 
 			stat2qid(&st, &wqid);
@@ -614,7 +618,6 @@ static void virtio_p9_readdir(struct p9_dev *p9dev,
 	struct stat st;
 	struct p9_fid *fid;
 	struct dirent *dent;
-	char full_path[PATH_MAX];
 	u64 offset, old_offset;
 
 	rcount = 0;
@@ -645,11 +648,8 @@ static void virtio_p9_readdir(struct p9_dev *p9dev,
 			break;
 		}
 		old_offset = dent->d_off;
-		if (rel_to_abs(p9dev, dent->d_name, full_path, sizeof(full_path)) != 0) {
-			errno = ENAMETOOLONG;
-			goto err_out;
-		}
-		lstat(full_path, &st);
+		if (stat_rel(p9dev, dent->d_name, &st) != 0)
+			memset(&st, -1, sizeof(st));
 		stat2qid(&st, &qid);
 		read = pdu->write_offset;
 		virtio_p9_pdu_writef(pdu, "Qqbs", &qid, dent->d_off,
-- 
2.7.4

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