PATCH: pws-18: zftp system type detection

[Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>]

I discovered that some FTP servers, in particular the one currently in use
at sunsite.ic.ac.uk, don't let you send a SYST command until you're logged
in: this is sort of implied by RFC959, but most servers let you do it
anyway.  If you saw an unexpected '530 Not logged in' or '530 Please log in
with USER and PASS' or something such while opening a connection, that was
probably what was causing it.

The reply to the SYST command is what sets the $ZFTP_SYSTEM parameter and
turns the transfer type into image if the remote system is UNIX.  I can't
see any harm in moving the test unconditionally down to after login, but
I'm sure you'll let me know.  (You can always run `zftp quote SYST' and
look at $ZFTP_REPLY, if you want to see what happens; remember you can turn
off all these extra commands by putting a D for Dumb in $ZFTP_PREFS,
i.e. you probably want ZFTP_PREFS=PSD.  This will confuse the zf*
functions.  Yes, I know no-one cares.)

(Isn't it interesting we sometimes write `login' as a one-word verb, but
never say `loginned'?  Is the German eingelogged or eingelogt or even
eingeloggt, or maybe einlogiert or einloggiert?  Does the
Rechtschreibreform have something to say about this?)

--- Src/Modules/zftp.c.stat	Fri May 14 11:06:42 1999
+++ Src/Modules/zftp.c	Sat May 15 16:49:28 1999
@@ -250,25 +250,26 @@
  * --- we don't try to track it because it's too complicated.
  */
 enum {
-    ZFST_ASCI = 0x00,		/* type for next transfer is ASCII */
-    ZFST_IMAG = 0x01,		/* type for next transfer is image */
+    ZFST_ASCI = 0x0000,		/* type for next transfer is ASCII */
+    ZFST_IMAG = 0x0001,		/* type for next transfer is image */
 
-    ZFST_TMSK = 0x01,		/* mask for type flags */
-    ZFST_TBIT = 0x01,		/* number of bits in type flags */
+    ZFST_TMSK = 0x0001,		/* mask for type flags */
+    ZFST_TBIT = 0x0001,		/* number of bits in type flags */
 
-    ZFST_CASC = 0x00,		/* current type is ASCII - default */
-    ZFST_CIMA = 0x02,		/* current type is image */
+    ZFST_CASC = 0x0000,		/* current type is ASCII - default */
+    ZFST_CIMA = 0x0002,		/* current type is image */
 
-    ZFST_STRE = 0x00,		/* stream mode - default */
-    ZFST_BLOC = 0x04,		/* block mode */
-
-    ZFST_MMSK = 0x04,		/* mask for mode flags */
-
-    ZFST_LOGI = 0x08,		/* user logged in */
-    ZFST_NOPS = 0x10,		/* server doesn't understand PASV */
-    ZFST_NOSZ = 0x20,		/* server doesn't send `(XXXX bytes)' reply */
-    ZFST_TRSZ = 0x40,		/* tried getting 'size' from reply */
-    ZFST_CLOS = 0x80		/* connection closed */
+    ZFST_STRE = 0x0000,		/* stream mode - default */
+    ZFST_BLOC = 0x0004,		/* block mode */
+
+    ZFST_MMSK = 0x0004,		/* mask for mode flags */
+
+    ZFST_LOGI = 0x0008,		/* user logged in */
+    ZFST_SYST = 0x0010,		/* done system type check */
+    ZFST_NOPS = 0x0020,		/* server doesn't understand PASV */
+    ZFST_NOSZ = 0x0040,		/* server doesn't send `(XXXX bytes)' reply */
+    ZFST_TRSZ = 0x0080,		/* tried getting 'size' from reply */
+    ZFST_CLOS = 0x0100		/* connection closed */
 };
 #define ZFST_TYPE(x) (x & ZFST_TMSK)
 /*
@@ -1599,7 +1600,7 @@
     struct protoent *zprotop;
     struct servent *zservp;
     struct hostent *zhostp = NULL;
-    char **addrp, tbuf[2] = "X", *fname;
+    char **addrp, *fname;
     int err, len, tmout;
 
     if (!*args) {
@@ -1803,32 +1804,11 @@
 #endif
     unlink(fname);
 
-    /* now find out what system we're connected to */
-    if (!(zfprefs & ZFPF_DUMB) && zfsendcmd("SYST\r\n") == 2) {
-	char *ptr = lastmsg, *eptr, *systype;
-	for (eptr = ptr; *eptr; eptr++)
-	    ;
-	systype = ztrduppfx(ptr, eptr-ptr);
-	if (!strncmp(systype, "UNIX Type: L8", 13)) {
-	    /*
-	     * Use binary for transfers.  This simple test saves much
-	     * hassle for all concerned, particularly me.
-	     */
-	    zfstatus |= ZFST_IMAG;
-	    zfis_unix = 1;
-	}
-	/*
-	 * we could set zfis_unix based just on the UNIX part,
-	 * but I don't really know the consequences of that.
-	 */
-	zfsetparam("ZFTP_SYSTEM", systype, ZFPM_READONLY);
-    } else if (zcfd == -1) {
+    if (zcfd == -1) {
 	/* final paranoid check */
 	return 1;
     }
 	
-    tbuf[0] = (ZFST_TYPE(zfstatus) == ZFST_ASCI) ? 'A' : 'I';
-    zfsetparam("ZFTP_TYPE", ztrdup(tbuf), ZFPM_READONLY);
     zfsetparam("ZFTP_MODE", ztrdup("S"), ZFPM_READONLY);
     /* if remaining arguments, use them to log in. */
     if (zcfd > -1 && *++args)
@@ -1965,7 +1945,7 @@
 zftp_login(char *name, char **args, int flags)
 {
     char *ucmd, *passwd = NULL, *acct = NULL;
-    char *user;
+    char *user, tbuf[2] = "X";
     int stopit;
 
     if ((zfstatus & ZFST_LOGI) && zfsendcmd("REIN\r\n") >= 4)
@@ -2044,6 +2024,36 @@
     zfsetparam("ZFTP_USER", ztrdup(user), ZFPM_READONLY);
     if (acct)
 	zfsetparam("ZFTP_ACCOUNT", ztrdup(acct), ZFPM_READONLY);
+
+    /*
+     * Now find out what system we're connected to. Some systems
+     * won't let us do this until we're logged in; it's fairly safe
+     * to delay it here for all systems.
+     */
+    if (!(zfprefs & ZFPF_DUMB) && !(zfstatus & ZFST_SYST)) {
+	if (zfsendcmd("SYST\r\n") == 2) {
+	    char *ptr = lastmsg, *eptr, *systype;
+	    for (eptr = ptr; *eptr; eptr++)
+		;
+	    systype = ztrduppfx(ptr, eptr-ptr);
+	    if (!strncmp(systype, "UNIX Type: L8", 13)) {
+		/*
+		 * Use binary for transfers.  This simple test saves much
+		 * hassle for all concerned, particularly me.
+		 */
+		zfstatus |= ZFST_IMAG;
+		zfis_unix = 1;
+	    }
+	    /*
+	     * we could set zfis_unix based just on the UNIX part,
+	     * but I don't really know the consequences of that.
+	     */
+	    zfsetparam("ZFTP_SYSTEM", systype, ZFPM_READONLY);
+	}
+	zfstatus |= ZFST_SYST;
+    }
+    tbuf[0] = (ZFST_TYPE(zfstatus) == ZFST_ASCI) ? 'A' : 'I';
+    zfsetparam("ZFTP_TYPE", ztrdup(tbuf), ZFPM_READONLY);
 
     /*
      * Get the directory.  This is possibly an unnecessary overhead, of

-- 
Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarroti 2, 56127 Pisa, Italy