aboutsummaryrefslogtreecommitdiff
path: root/lib/tftp.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/tftp.c')
-rw-r--r--lib/tftp.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/tftp.c b/lib/tftp.c
index e9d17ee1d..f2cd3fb01 100644
--- a/lib/tftp.c
+++ b/lib/tftp.c
@@ -529,6 +529,25 @@ CURLcode Curl_tftp_connect(struct connectdata *conn, bool *done)
tftp_state_data_t *state;
int rc;
+ /*
+ * The TFTP code is not portable because it sends C structs directly over
+ * the wire. Since C gives compiler writers a wide latitude in padding and
+ * aligning structs, this fails on many architectures (e.g. ARM).
+ *
+ * The only portable way to fix this is to copy each struct item into a
+ * flat buffer and send the flat buffer instead of the struct. The
+ * alternative, trying to get the compiler to eliminate padding bytes
+ * within the struct, is a nightmare to maintain (each compiler does it
+ * differently), and is still not guaranteed to work because some
+ * architectures can't handle the resulting alignment.
+ *
+ * This check can be removed once the code has been fixed.
+ */
+ if(sizeof(struct tftp_packet) != 516) {
+ failf(conn->data, "tftp not supported on this architecture");
+ return CURLE_FAILED_INIT;
+ }
+
if((state = conn->proto.tftp = calloc(sizeof(tftp_state_data_t), 1))==NULL) {
return CURLE_OUT_OF_MEMORY;
}