smtp: General tidy up ready for adding NTLM support

Changed the name of variable l, in several functions, which represents
the length of strings being sent to the server, to len which is more
meaningful and consistent with other code in smtp.c and elsewhere.

Reworked smtp_authenticate() to be simpler and easier to follow.
Variables and now initialised in their definitions and if no username
and password are specified the function sets the state to SMTP_STOP and
returns immediately, rather than being part of a huge if statement.

1 files changed, 72 insertions, 71 deletions

diff --git a/lib/smtp.c b/lib/smtp.c
index 75b008ef2..6d99d36dd 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -111,7 +111,6 @@ static CURLcode smtp_doing(struct connectdata *conn,
 static CURLcode smtp_setup_connection(struct connectdata * conn);
 static CURLcode smtp_state_upgrade_tls(struct connectdata *conn);
 
-
 /*
  * SMTP protocol handler.
  */
@@ -135,7 +134,6 @@ const struct Curl_handler Curl_handler_smtp = {
   PROTOPT_CLOSEACTION               /* flags */
 };
 
-
 #ifdef USE_SSL
 /*
  * SMTPS protocol handler.
@@ -185,7 +183,6 @@ static const struct Curl_handler Curl_handler_smtp_proxy = {
   PROTOPT_NONE                          /* flags */
 };
 
-
 #ifdef USE_SSL
 /*
  * HTTP-proxyed SMTPS protocol handler.
@@ -212,7 +209,6 @@ static const struct Curl_handler Curl_handler_smtps_proxy = {
 #endif
 #endif
 
-
 /* Function that checks for an ending smtp status code at the start of the
    given string.
    As a side effect, it also flags allowed authentication mechanisms according
@@ -388,64 +384,61 @@ static CURLcode smtp_authenticate(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct smtp_conn *smtpc = &conn->proto.smtpc;
-  char * initresp;
-  const char * mech;
-  size_t l;
-  smtpstate state1;
-  smtpstate state2;
-
-  if(!conn->bits.user_passwd)
-    state(conn, SMTP_STOP);             /* End of connect phase. */
-  else {
-    initresp = (char *) NULL;
-    l = 1;
+  char *initresp = NULL;
+  const char *mech = NULL;
+  size_t len = 0;
+  smtpstate state1 = SMTP_STOP;
+  smtpstate state2 = SMTP_STOP;
+
+  /* Check we have a username and password to authenticate with and end the
+     connect phase if we don't. */
+  if(!conn->bits.user_passwd) {
+    state(conn, SMTP_STOP);
 
-    /* Check supported authentication mechanisms by decreasing order of
-       security. */
-    mech = (const char *) NULL;         /* Avoid compiler warnings. */
-    state1 = SMTP_STOP;
-    state2 = SMTP_STOP;
+    return result;
+  }
 
+  /* Check supported authentication mechanisms by decreasing order of
+     security. */
 #ifndef CURL_DISABLE_CRYPTO_AUTH
-    if(smtpc->authmechs & SMTP_AUTH_CRAM_MD5) {
-      mech = "CRAM-MD5";
-      state1 = SMTP_AUTHCRAM;
-    }
-    else
+  if(smtpc->authmechs & SMTP_AUTH_CRAM_MD5) {
+    mech = "CRAM-MD5";
+    state1 = SMTP_AUTHCRAM;
+  }
+  else
 #endif
-    if(smtpc->authmechs & SMTP_AUTH_LOGIN) {
-      mech = "LOGIN";
-      state1 = SMTP_AUTHLOGIN;
-      state2 = SMTP_AUTHPASSWD;
-      result = smtp_auth_login_user(conn, &initresp, &l);
-    }
-    else if(smtpc->authmechs & SMTP_AUTH_PLAIN) {
-      mech = "PLAIN";
-      state1 = SMTP_AUTHPLAIN;
-      state2 = SMTP_AUTH;
-      result = smtp_auth_plain_data(conn, &initresp, &l);
-    }
-    else {
-      infof(conn->data, "No known auth mechanisms supported!\n");
-      result = CURLE_LOGIN_DENIED;      /* Other mechanisms not supported. */
-    }
+  if(smtpc->authmechs & SMTP_AUTH_LOGIN) {
+    mech = "LOGIN";
+    state1 = SMTP_AUTHLOGIN;
+    state2 = SMTP_AUTHPASSWD;
+    result = smtp_auth_login_user(conn, &initresp, &len);
+  }
+  else if(smtpc->authmechs & SMTP_AUTH_PLAIN) {
+    mech = "PLAIN";
+    state1 = SMTP_AUTHPLAIN;
+    state2 = SMTP_AUTH;
+    result = smtp_auth_plain_data(conn, &initresp, &len);
+  }
+  else {
+    infof(conn->data, "No known auth mechanisms supported!\n");
+    result = CURLE_LOGIN_DENIED;      /* Other mechanisms not supported. */
+  }
 
-    if(!result) {
-      if(initresp &&
-         l + strlen(mech) <= 512 - 8) { /* AUTH <mech> ...<crlf> */
-        result = Curl_pp_sendf(&smtpc->pp, "AUTH %s %s", mech, initresp);
+  if(!result) {
+    if(initresp &&
+       strlen(mech) + len <= 512 - 8) { /* AUTH <mech> ...<crlf> */
+       result = Curl_pp_sendf(&smtpc->pp, "AUTH %s %s", mech, initresp);
 
-        if(!result)
-          state(conn, state2);
-      }
-      else {
-        result = Curl_pp_sendf(&smtpc->pp, "AUTH %s", mech);
+      if(!result)
+        state(conn, state2);
+    }
+    else {
+      result = Curl_pp_sendf(&smtpc->pp, "AUTH %s", mech);
 
-        if(!result)
-          state(conn, state1);
-      }
-      Curl_safefree(initresp);
+      if(!result)
+        state(conn, state1);
     }
+    Curl_safefree(initresp);
   }
 
   return result;
@@ -498,6 +491,7 @@ static CURLcode smtp_state_starttls_resp(struct connectdata *conn,
       }
     }
   }
+
   return result;
 }
 
@@ -565,6 +559,7 @@ static CURLcode smtp_state_helo_resp(struct connectdata *conn,
     /* end the connect phase */
     state(conn, SMTP_STOP);
   }
+
   return result;
 }
 
@@ -575,8 +570,8 @@ static CURLcode smtp_state_authplain_resp(struct connectdata *conn,
 {
   CURLcode result = CURLE_OK;
   struct SessionHandle *data = conn->data;
-  size_t l = 0;
-  char * plainauth = NULL;
+  size_t len = 0;
+  char *plainauth = NULL;
 
   (void)instate; /* no use for this yet */
 
@@ -585,7 +580,7 @@ static CURLcode smtp_state_authplain_resp(struct connectdata *conn,
     result = CURLE_LOGIN_DENIED;
   }
   else {
-    result = smtp_auth_plain_data(conn, &plainauth, &l);
+    result = smtp_auth_plain_data(conn, &plainauth, &len);
 
     if(!result) {
       if(plainauth) {
@@ -608,8 +603,8 @@ static CURLcode smtp_state_authlogin_resp(struct connectdata *conn,
 {
   CURLcode result = CURLE_OK;
   struct SessionHandle *data = conn->data;
-  size_t l = 0;
-  char * authuser = NULL;
+  size_t len = 0;
+  char *authuser = NULL;
 
   (void)instate; /* no use for this yet */
 
@@ -618,7 +613,7 @@ static CURLcode smtp_state_authlogin_resp(struct connectdata *conn,
     result = CURLE_LOGIN_DENIED;
   }
   else {
-    result = smtp_auth_login_user(conn, &authuser, &l);
+    result = smtp_auth_login_user(conn, &authuser, &len);
 
     if(!result) {
       if(authuser) {
@@ -642,7 +637,7 @@ static CURLcode smtp_state_authpasswd_resp(struct connectdata *conn,
   CURLcode result = CURLE_OK;
   struct SessionHandle *data = conn->data;
   size_t plen;
-  size_t l = 0;
+  size_t len = 0;
   char *authpasswd = NULL;
 
   (void)instate; /* no use for this yet */
@@ -657,7 +652,7 @@ static CURLcode smtp_state_authpasswd_resp(struct connectdata *conn,
     if(!plen)
       result = Curl_pp_sendf(&conn->proto.smtpc.pp, "=");
     else {
-      result = Curl_base64_encode(data, conn->passwd, plen, &authpasswd, &l);
+      result = Curl_base64_encode(data, conn->passwd, plen, &authpasswd, &len);
 
       if(!result) {
         if(authpasswd) {
@@ -686,9 +681,9 @@ static CURLcode smtp_state_authcram_resp(struct connectdata *conn,
   char * chlg64 = data->state.buffer;
   unsigned char * chlg;
   size_t chlglen;
-  size_t l = 0;
-  char * rplyb64 = NULL;
-  HMAC_context * ctxt;
+  size_t len = 0;
+  char *rplyb64 = NULL;
+  HMAC_context *ctxt;
   unsigned char digest[16];
   char reply[MAX_CURL_USER_LENGTH + 32 /* 2 * size of MD5 digest */ + 1];
 
@@ -707,13 +702,13 @@ static CURLcode smtp_state_authcram_resp(struct connectdata *conn,
   chlglen = 0;
 
   if(*chlg64 != '=') {
-    for(l = strlen(chlg64); l--;)
-      if(chlg64[l] != '\r' && chlg64[l] != '\n' && chlg64[l] != ' ' &&
-         chlg64[l] != '\t')
+    for(len = strlen(chlg64); len--;)
+      if(chlg64[len] != '\r' && chlg64[len] != '\n' && chlg64[len] != ' ' &&
+         chlg64[len] != '\t')
         break;
 
-    if(++l) {
-      chlg64[l] = '\0';
+    if(++len) {
+      chlg64[len] = '\0';
 
       result = Curl_base64_decode(chlg64, &chlg, &chlglen);
       if(result)
@@ -747,7 +742,7 @@ static CURLcode smtp_state_authcram_resp(struct connectdata *conn,
            digest[12], digest[13], digest[14], digest[15]);
 
   /* Encode it to base64 and send it. */
-  result = Curl_base64_encode(data, reply, 0, &rplyb64, &l);
+  result = Curl_base64_encode(data, reply, 0, &rplyb64, &len);
 
   if(!result) {
     if(rplyb64) {
@@ -849,6 +844,7 @@ static CURLcode smtp_rcpt_to(struct connectdata *conn)
     if(!result)
       state(conn, SMTP_RCPT);
   }
+
   return result;
 }
 
@@ -909,6 +905,7 @@ static CURLcode smtp_state_rcpt_resp(struct connectdata *conn,
 
     state(conn, SMTP_DATA);
   }
+
   return result;
 }
 
@@ -949,6 +946,7 @@ static CURLcode smtp_state_postdata_resp(struct connectdata *conn,
     result = CURLE_RECV_ERROR;
 
   state(conn, SMTP_STOP);
+
   return result;
 }
 
@@ -1046,6 +1044,7 @@ static CURLcode smtp_statemach_act(struct connectdata *conn)
       break;
     }
   }
+
   return result;
 }
 
@@ -1440,6 +1439,7 @@ static CURLcode smtp_doing(struct connectdata *conn,
 
     DEBUGF(infof(conn->data, "DO phase is complete\n"));
   }
+
   return result;
 }
 
@@ -1579,6 +1579,7 @@ CURLcode Curl_smtp_escape_eob(struct connectdata *conn, ssize_t nread)
     /* set the new amount too */
     data->req.upload_present = nread;
   }
+
   return CURLE_OK;
 }