fs: fat: document path transformation
The FAT driver converts zephyr paths like /SD:/foo into ELM-FATFS paths
like SD:/foo. Document this behaviour by extracting it into a separate
function (and adding a sanity check).
Signed-off-by: Armin Brauns <armin.brauns@embedded-solutions.at>
diff --git a/subsys/fs/fat_fs.c b/subsys/fs/fat_fs.c
index ffd20c3..c7fef42 100644
--- a/subsys/fs/fat_fs.c
+++ b/subsys/fs/fat_fs.c
@@ -64,6 +64,17 @@
return -EIO;
}
+/* Converts a zephyr path like /SD:/foo into a path digestible by FATFS by stripping the
+ * leading slash, i.e. SD:/foo.
+ */
+static const char *translate_path(const char *path)
+{
+ /* this is guaranteed by the fs subsystem */
+ __ASSERT_NO_MSG(path[0] == '/');
+
+ return &path[1];
+}
+
static uint8_t translate_flags(fs_mode_t flags)
{
uint8_t fat_mode = 0;
@@ -97,7 +108,7 @@
fs_mode = translate_flags(mode);
- res = f_open(zfp->filep, &file_name[1], fs_mode);
+ res = f_open(zfp->filep, translate_path(file_name), fs_mode);
if (res != FR_OK) {
k_mem_slab_free(&fatfs_filep_pool, &ptr);
@@ -125,7 +136,7 @@
int res = -ENOTSUP;
#if !defined(CONFIG_FS_FATFS_READ_ONLY)
- res = f_unlink(&path[1]);
+ res = f_unlink(translate_path(path));
res = translate_error(res);
#endif
@@ -142,14 +153,14 @@
FILINFO fno;
/* Check if 'to' path exists; remove it if it does */
- res = f_stat(&to[1], &fno);
+ res = f_stat(translate_path(to), &fno);
if (FR_OK == res) {
- res = f_unlink(&to[1]);
+ res = f_unlink(translate_path(to));
if (FR_OK != res)
return translate_error(res);
}
- res = f_rename(&from[1], &to[1]);
+ res = f_rename(translate_path(from), translate_path(to));
res = translate_error(res);
#endif
@@ -301,7 +312,7 @@
int res = -ENOTSUP;
#if !defined(CONFIG_FS_FATFS_READ_ONLY)
- res = f_mkdir(&path[1]);
+ res = f_mkdir(translate_path(path));
res = translate_error(res);
#endif
@@ -320,7 +331,7 @@
return -ENOMEM;
}
- res = f_opendir(zdp->dirp, &path[1]);
+ res = f_opendir(zdp->dirp, translate_path(path));
if (res != FR_OK) {
k_mem_slab_free(&fatfs_dirp_pool, &ptr);
@@ -366,7 +377,7 @@
FRESULT res;
FILINFO fno;
- res = f_stat(&path[1], &fno);
+ res = f_stat(translate_path(path), &fno);
if (res == FR_OK) {
entry->type = ((fno.fattrib & AM_DIR) ?
FS_DIR_ENTRY_DIR : FS_DIR_ENTRY_FILE);
@@ -385,7 +396,7 @@
FATFS *fs;
DWORD f_bfree = 0;
- res = f_getfree(&mountp->mnt_point[1], &f_bfree, &fs);
+ res = f_getfree(translate_path(mountp->mnt_point), &f_bfree, &fs);
if (res != FR_OK) {
return -EIO;
}
@@ -414,7 +425,7 @@
{
FRESULT res;
- res = f_mount((FATFS *)mountp->fs_data, &mountp->mnt_point[1], 1);
+ res = f_mount((FATFS *)mountp->fs_data, translate_path(mountp->mnt_point), 1);
#if defined(CONFIG_FS_FATFS_MOUNT_MKFS)
if (res == FR_NO_FILESYSTEM &&
@@ -433,10 +444,10 @@
.au_size = 0 /* Auto calculate cluster size */
};
- res = f_mkfs(&mountp->mnt_point[1], &mkfs_opt, work, sizeof(work));
+ res = f_mkfs(translate_path(mountp->mnt_point), &mkfs_opt, work, sizeof(work));
if (res == FR_OK) {
res = f_mount((FATFS *)mountp->fs_data,
- &mountp->mnt_point[1], 1);
+ translate_path(mountp->mnt_point), 1);
}
}
#endif /* CONFIG_FS_FATFS_MOUNT_MKFS */
@@ -453,7 +464,7 @@
{
FRESULT res;
- res = f_mount(NULL, &mountp->mnt_point[1], 0);
+ res = f_mount(NULL, translate_path(mountp->mnt_point), 0);
return translate_error(res);
}
