tools/mpremote: Support OSError's on targets without errno.

Targets without the `errno` module enabled will not render `OSError`s
with the name of the error.  Instead they just print the numeric error
code.

Add support for such targets by explicitly recognising certain error codes.

Signed-off-by: Damien George <damien@micropython.org>

tools/mpremote/mpremote/mp_errno.py

@@ -0,0 +1,53 @@
+import errno
+
+# This table maps numeric values defined by `py/mperrno.h` to host errno code.
+MP_ERRNO_TABLE = {
+    1: errno.EPERM,
+    2: errno.ENOENT,
+    3: errno.ESRCH,
+    4: errno.EINTR,
+    5: errno.EIO,
+    6: errno.ENXIO,
+    7: errno.E2BIG,
+    8: errno.ENOEXEC,
+    9: errno.EBADF,
+    10: errno.ECHILD,
+    11: errno.EAGAIN,
+    12: errno.ENOMEM,
+    13: errno.EACCES,
+    14: errno.EFAULT,
+    15: errno.ENOTBLK,
+    16: errno.EBUSY,
+    17: errno.EEXIST,
+    18: errno.EXDEV,
+    19: errno.ENODEV,
+    20: errno.ENOTDIR,
+    21: errno.EISDIR,
+    22: errno.EINVAL,
+    23: errno.ENFILE,
+    24: errno.EMFILE,
+    25: errno.ENOTTY,
+    26: errno.ETXTBSY,
+    27: errno.EFBIG,
+    28: errno.ENOSPC,
+    29: errno.ESPIPE,
+    30: errno.EROFS,
+    31: errno.EMLINK,
+    32: errno.EPIPE,
+    33: errno.EDOM,
+    34: errno.ERANGE,
+    95: errno.EOPNOTSUPP,
+    97: errno.EAFNOSUPPORT,
+    98: errno.EADDRINUSE,
+    103: errno.ECONNABORTED,
+    104: errno.ECONNRESET,
+    105: errno.ENOBUFS,
+    106: errno.EISCONN,
+    107: errno.ENOTCONN,
+    110: errno.ETIMEDOUT,
+    111: errno.ECONNREFUSED,
+    113: errno.EHOSTUNREACH,
+    114: errno.EALREADY,
+    115: errno.EINPROGRESS,
+    125: errno.ECANCELED,
+}

tools/mpremote/mpremote/transport.py

@@ -24,8 +24,9 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
 
-import ast, errno, hashlib, os, sys
+import ast, errno, hashlib, os, re, sys
 from collections import namedtuple
+from .mp_errno import MP_ERRNO_TABLE
 
 
 def stdout_write_bytes(b):
@@ -62,6 +63,16 @@ def _convert_filesystem_error(e, info):
         ]:
             if estr in e.error_output:
                 return OSError(code, info)
+
+        # Some targets don't render OSError with the name of the errno, so in these
+        # cases support an explicit mapping of errnos to known numeric codes.
+        error_lines = e.error_output.splitlines()
+        match = re.match(r"OSError: (\d+)$", error_lines[-1])
+        if match:
+            value = int(match.group(1), 10)
+            if value in MP_ERRNO_TABLE:
+                return OSError(MP_ERRNO_TABLE[value], info)
+
     return e