[tftp] Eliminate unnecessary variable-length stack allocation

Eliminate an unnecessary variable-length stack allocation and memory
copy by allowing TFTP option processors to modify the option string
in-place.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/net/udp/tftp.c b/src/net/udp/tftp.c
index 6ce27497c224e982fa73f0af9aaa5c205c97dad0..a0dac1ec58b8e02643bd4182b6098822aa36afa9 100644 (file)
--- a/src/net/udp/tftp.c
+++ b/src/net/udp/tftp.c
@@ -545,8 +545,7 @@ static void tftp_timer_expired ( struct retry_timer *timer, int fail ) {
  * @v value            Option value
  * @ret rc             Return status code
  */
-static int tftp_process_blksize ( struct tftp_request *tftp,
-                                 const char *value ) {
+static int tftp_process_blksize ( struct tftp_request *tftp, char *value ) {
        char *end;
 
        tftp->blksize = strtoul ( value, &end, 10 );
@@ -567,8 +566,7 @@ static int tftp_process_blksize ( struct tftp_request *tftp,
  * @v value            Option value
  * @ret rc             Return status code
  */
-static int tftp_process_tsize ( struct tftp_request *tftp,
-                               const char *value ) {
+static int tftp_process_tsize ( struct tftp_request *tftp, char *value ) {
        char *end;
 
        tftp->tsize = strtoul ( value, &end, 10 );
@@ -589,13 +587,11 @@ static int tftp_process_tsize ( struct tftp_request *tftp,
  * @v value            Option value
  * @ret rc             Return status code
  */
-static int tftp_process_multicast ( struct tftp_request *tftp,
-                                   const char *value ) {
+static int tftp_process_multicast ( struct tftp_request *tftp, char *value ) {
        union {
                struct sockaddr sa;
                struct sockaddr_in sin;
        } socket;
-       char buf[ strlen ( value ) + 1 ];
        char *addr;
        char *port;
        char *port_end;
@@ -604,8 +600,7 @@ static int tftp_process_multicast ( struct tftp_request *tftp,
        int rc;
 
        /* Split value into "addr,port,mc" fields */
-       memcpy ( buf, value, sizeof ( buf ) );
-       addr = buf;
+       addr = value;
        port = strchr ( addr, ',' );
        if ( ! port ) {
                DBGC ( tftp, "TFTP %p multicast missing port,mc\n", tftp );
@@ -662,7 +657,7 @@ struct tftp_option {
         * @v value     Option value
         * @ret rc      Return status code
         */
-       int ( * process ) ( struct tftp_request *tftp, const char *value );
+       int ( * process ) ( struct tftp_request *tftp, char *value );
 };
 
 /** Recognised TFTP options */
@@ -682,7 +677,7 @@ static struct tftp_option tftp_options[] = {
  * @ret rc             Return status code
  */
 static int tftp_process_option ( struct tftp_request *tftp,
-                                const char *name, const char *value ) {
+                                const char *name, char *value ) {
        struct tftp_option *option;
 
        for ( option = tftp_options ; option->name ; option++ ) {