sendmail: support AUTH PLAIN in addition to AUTH LOGIN

Implement the -am argument to allow choosing an AUTH method.
For now only PLAIN and LOGIN are supported, but others can be added
easily in the future.

AUTH PLAIN required adding a new variant of encode_base64() capable of
handling NUL characters in the input string; the old function is now a
wrapper for the newer one.

function                                             old     new   delta
encode_n_base64                                        -     236    +236
sendmail_main                                       1199    1380    +181
packed_usage                                       32873   32877      +4
encode_base64                                        242      36    -206
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/1 up/down: 421/-206)          Total: 215 bytes

Signed-off-by: Raffaello D. Di Napoli <rafdev@dinapo.li>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 12 insertions, 6 deletions

diff --git a/mailutils/mail.c b/mailutils/mail.c
index 7af7edd6c..2ad959f7d 100644
--- a/mailutils/mail.c
+++ b/mailutils/mail.c
@@ -109,6 +109,17 @@ static char* FAST_FUNC parse_url(char *url, char **user, char **pass)
 
 void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol)
 {
+        size_t len = len;
+        if (text) {
+                // though we do not call uuencode(NULL, NULL) explicitly
+                // still we do not want to break things suddenly
+                len = strlen(text);
+        }
+        encode_n_base64(fname, text, len, eol);
+}
+
+void FAST_FUNC encode_n_base64(char *fname, const char *text, size_t len, const char *eol)
+{
         enum {
                 SRC_BUF_SIZE = 57,  /* This *MUST* be a multiple of 3 */
                 DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
@@ -116,17 +127,12 @@ void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol)
 #define src_buf text
         char src[SRC_BUF_SIZE];
         FILE *fp = fp;
-        ssize_t len = len;
         char dst_buf[DST_BUF_SIZE + 1];
 
         if (fname) {
                 fp = (NOT_LONE_DASH(fname)) ? xfopen_for_read(fname) : (FILE *)text;
                 src_buf = src;
-        } else if (text) {
-                // though we do not call uuencode(NULL, NULL) explicitly
-                // still we do not want to break things suddenly
-                len = strlen(text);
-        } else
+        } else if (!text)
                 return;
 
         while (1) {