Fixed issue with trailing dots in file paths

Paths such as the following were causing issues:
/tea/hottea/.
/tea/hottea/..

Unfortunately the existing structure for path lookup didn't make it very
easy to introduce proper handling in this case without duplicating the
entire skip logic for paths. So the lfs_dir_find function had to be
restructured a bit.

One odd side-effect of this is that now lfs_dir_find includes the
initial fetch operation. This kinda breaks the fetch -> op pattern of
the dir functions, but does come with a nice code size reduction.

lfs.c

@@ -305,7 +305,6 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
         }
 
         // check if we have looked at all blocks since last ack
-        //if (lfs->free.i == lfs->free.ack - lfs->free.off) {
         if (lfs->free.ack == 0) {
             LFS_WARN("No more free space %d", lfs->free.i + lfs->free.off);
             return LFS_ERR_NOSPC;
@@ -784,26 +783,19 @@ static int lfs_dir_find(lfs_t *lfs, lfs_dir_t *dir,
         lfs_entry_t *entry, const char **path) {
     const char *pathname = *path;
     size_t pathlen;
+    entry->d.type = LFS_TYPE_DIR;
+    entry->d.elen = sizeof(entry->d) - 4;
+    entry->d.alen = 0;
+    entry->d.nlen = 0;
+    entry->d.u.dir[0] = lfs->root[0];
+    entry->d.u.dir[1] = lfs->root[1];
 
     while (true) {
-    nextname:
+nextname:
         // skip slashes
         pathname += strspn(pathname, "/");
         pathlen = strcspn(pathname, "/");
 
-        // special case for root dir
-        if (pathname[0] == '\0') {
-            *entry = (lfs_entry_t){
-                .d.type = LFS_TYPE_DIR,
-                .d.elen = sizeof(entry->d) - 4,
-                .d.alen = 0,
-                .d.nlen = 0,
-                .d.u.dir[0] = lfs->root[0],
-                .d.u.dir[1] = lfs->root[1],
-            };
-            return 0;
-        }
-
         // skip '.' and root '..'
         if ((pathlen == 1 && memcmp(pathname, ".", 1) == 0) ||
             (pathlen == 2 && memcmp(pathname, "..", 2) == 0)) {
@@ -835,10 +827,25 @@ static int lfs_dir_find(lfs_t *lfs, lfs_dir_t *dir,
             suffix += sufflen;
         }
 
+        // found path
+        if (pathname[0] == '\0') {
+            return 0;
+        }
+
         // update what we've found
         *path = pathname;
 
-        // find path
+        // continue on if we hit a directory
+        if (entry->d.type != LFS_TYPE_DIR) {
+            return LFS_ERR_NOTDIR;
+        }
+
+        int err = lfs_dir_fetch(lfs, dir, entry->d.u.dir);
+        if (err) {
+            return err;
+        }
+
+        // find entry matching name
         while (true) {
             int err = lfs_dir_next(lfs, dir, entry);
             if (err) {
@@ -874,21 +881,8 @@ static int lfs_dir_find(lfs_t *lfs, lfs_dir_t *dir,
             entry->d.type &= ~0x80;
         }
 
+        // to next name
         pathname += pathlen;
-        pathname += strspn(pathname, "/");
-        if (pathname[0] == '\0') {
-            return 0;
-        }
-
-        // continue on if we hit a directory
-        if (entry->d.type != LFS_TYPE_DIR) {
-            return LFS_ERR_NOTDIR;
-        }
-
-        int err = lfs_dir_fetch(lfs, dir, entry->d.u.dir);
-        if (err) {
-            return err;
-        }
     }
 }
 
@@ -905,13 +899,8 @@ int lfs_mkdir(lfs_t *lfs, const char *path) {
 
     // fetch parent directory
     lfs_dir_t cwd;
-    int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, &cwd, &entry, &path);
+    int err = lfs_dir_find(lfs, &cwd, &entry, &path);
     if (err != LFS_ERR_NOENT || strchr(path, '/') != NULL) {
         return err ? err : LFS_ERR_EXIST;
     }
@@ -955,13 +944,8 @@ int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path) {
     dir->pair[0] = lfs->root[0];
     dir->pair[1] = lfs->root[1];
 
-    int err = lfs_dir_fetch(lfs, dir, dir->pair);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, dir, &entry, &path);
+    int err = lfs_dir_find(lfs, dir, &entry, &path);
     if (err) {
         return err;
     } else if (entry.d.type != LFS_TYPE_DIR) {
@@ -1303,13 +1287,8 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
 
     // allocate entry for file if it doesn't exist
     lfs_dir_t cwd;
-    int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, &cwd, &entry, &path);
+    int err = lfs_dir_find(lfs, &cwd, &entry, &path);
     if (err && (err != LFS_ERR_NOENT || strchr(path, '/') != NULL)) {
         return err;
     }
@@ -1815,13 +1794,8 @@ lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file) {
 /// General fs operations ///
 int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
     lfs_dir_t cwd;
-    int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, &cwd, &entry, &path);
+    int err = lfs_dir_find(lfs, &cwd, &entry, &path);
     if (err) {
         return err;
     }
@@ -1856,13 +1830,8 @@ int lfs_remove(lfs_t *lfs, const char *path) {
     }
 
     lfs_dir_t cwd;
-    int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, &cwd, &entry, &path);
+    int err = lfs_dir_find(lfs, &cwd, &entry, &path);
     if (err) {
         return err;
     }
@@ -1917,24 +1886,14 @@ int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
 
     // find old entry
     lfs_dir_t oldcwd;
-    int err = lfs_dir_fetch(lfs, &oldcwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t oldentry;
-    err = lfs_dir_find(lfs, &oldcwd, &oldentry, &oldpath);
+    int err = lfs_dir_find(lfs, &oldcwd, &oldentry, &oldpath);
     if (err) {
         return err;
     }
 
     // allocate new entry
     lfs_dir_t newcwd;
-    err = lfs_dir_fetch(lfs, &newcwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t preventry;
     err = lfs_dir_find(lfs, &newcwd, &preventry, &newpath);
     if (err && (err != LFS_ERR_NOENT || strchr(newpath, '/') != NULL)) {

tests/test_alloc.sh

@@ -110,35 +110,10 @@ lfs_alloc_singleproc multiprocreuse
 lfs_verify multiprocreuse
 lfs_verify singleprocreuse
 
+echo "--- Cleanup ---"
 lfs_remove multiprocreuse
 lfs_remove singleprocreuse
 
-echo "--- Lookahead overflow test ---"
-lfs_mkdir overflow
-for name in bacon eggs pancakes
-do
-tests/test.py << TEST
-    lfs_mount(&lfs, &cfg) => 0;
-
-//    // setup lookahead to almost overflow
-//    lfs.free.begin = ((lfs_size_t)-1) - 2*$SIZE;
-//    lfs.free.size = 0;
-//    lfs.free.off = 0;
-
-    lfs_file_open(&lfs, &file[0], "overflow/$name",
-            LFS_O_WRONLY | LFS_O_CREAT | LFS_O_APPEND) => 0;
-    size = strlen("$name");
-    memcpy(buffer, "$name", size);
-    for (int i = 0; i < $SIZE; i++) {
-        lfs_file_write(&lfs, &file[0], buffer, size) => size;
-    }
-    lfs_file_close(&lfs, &file[0]) => 0;
-    lfs_unmount(&lfs) => 0;
-TEST
-done
-lfs_verify overflow
-lfs_remove overflow
-
 echo "--- Exhaustion test ---"
 tests/test.py << TEST
     lfs_mount(&lfs, &cfg) => 0;
@@ -393,6 +368,7 @@ echo "--- Outdated lookahead and split dir test ---"
 rm -rf blocks
 tests/test.py << TEST
     lfs_format(&lfs, &cfg) => 0;
+
     lfs_mount(&lfs, &cfg) => 0;
 
     // fill completely with two files
@@ -448,8 +424,5 @@ tests/test.py << TEST
     lfs_unmount(&lfs) => 0;
 TEST
 
-
-
-
 echo "--- Results ---"
 tests/stats.py

tests/test_paths.sh

@@ -90,6 +90,22 @@ tests/test.py << TEST
     lfs_unmount(&lfs) => 0;
 TEST
 
+echo "--- Trailing dot path tests ---"
+tests/test.py << TEST
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_stat(&lfs, "tea/hottea/", &info) => 0;
+    strcmp(info.name, "hottea") => 0;
+    lfs_stat(&lfs, "tea/hottea/.", &info) => 0;
+    strcmp(info.name, "hottea") => 0;
+    lfs_stat(&lfs, "tea/hottea/./.", &info) => 0;
+    strcmp(info.name, "hottea") => 0;
+    lfs_stat(&lfs, "tea/hottea/..", &info) => 0;
+    strcmp(info.name, "tea") => 0;
+    lfs_stat(&lfs, "tea/hottea/../.", &info) => 0;
+    strcmp(info.name, "tea") => 0;
+    lfs_unmount(&lfs) => 0;
+TEST
+
 echo "--- Root dot dot path tests ---"
 tests/test.py << TEST
     lfs_mount(&lfs, &cfg) => 0;