Rethink and reimpliment the way RESTARTS are handled. The method I inheirited

from jmz was a hopeless kludge (sorry Jean-Marc :) and handled the problem
in the wrong way.  ftpRestart() has now gone away and ftpGet() has grown a
new parameter.

lib/libftpio/ftpio.3

@@ -36,7 +36,6 @@
 .Nm ftpPut ,
 .Nm ftpBinary ,
 .Nm ftpPassive ,
-.Nm ftpRestart ,
 .Nm ftpGetURL ,
 .Nm ftpPutURL ,
 .Nd FTPIO User library
@@ -53,15 +52,13 @@
 .Ft size_t
 .Fn ftpGetSize "FILE *fp, char *file"
 .Ft FILE *
-.Fn ftpGet "FILE *fp, char *file"
+.Fn ftpGet "FILE *fp, char *file, int *seekto"
 .Ft FILE *
 .Fn ftpPut "FILE *fp, char *file"
 .Ft int
 .Fn ftpBinary "FILE *fp, int status"
 .Ft int
 .Fn ftpPassive "FILE *fp, int status"
-.Ft int
-.Fn ftpRestart "FILE *fp, int where"
 .Ft FILE *
 .Fn ftpGetURL "char *url, char *user, char *passwd"
 .Ft FILE *
@@ -79,10 +76,8 @@ and
 fields (if passed as 0,
 .Fa ftp_port
 defaults to the standard ftp port of 21).  If it is successful, a
-standard
-.Fa stream
-descriptor is returned which should be passed to subsequent FTP
-operations. On failure, NULL is returned and
+standard stream descriptor is returned which should be passed to
+subsequent FTP operations. On failure, NULL is returned and
 .Fn ftpErrno
 will return the error code returned by the foreign server.
 .Pp
@@ -101,9 +96,17 @@ attempts to retreive the file named by the
 argument (which is assumed to be relative to the FTP server's current directory,
 see
 .Fn ftpChdir )
-and returns a new
-.Fa stream
-pointer for the file or NULL on failure.
+and returns a new stream pointer for the file or NULL on failure.  If
+.Fa seekto
+is non-NULL, the contents of the integer it points to will be used
+as a restart point for the file, that is to say that the stream
+returned will point
+.Fa *seekto
+bytes into the file gotten (this is handy for restarting failed
+transfers efficiently).  If the seek operation succeeds, the value
+of
+.Fa *seekto
+will be zero'd.
 .Pp
 .Fn ftpGetModtime
 returns the last modification time of the file named by the
@@ -137,15 +140,6 @@ sets passive mode (for firewalls) for the current server connection named by
 to boolean value
 .Fa status .
 .Pp
-.Fn ftpRestart
-requests that if the remote server supports restart operations, the offset
-in bytes specified in
-.Fa where
-should be used in the next file get operation to resume transferring from
-that location.  This is handy for restarting long get operations which have
-aborted in the middle without re-transferring wasted bytes.  Returns the
-old seek value, if any.
-.Pp
 .Fn ftpGetURL
 attempts to retreive the file named by the supplied
 .Fa URL
@@ -168,11 +162,10 @@ and can be considered equivalent to the combined
 .Fn ftpChdir
 and
 .Fn ftpPut
-operations except that no server
-.Fa stream
-is ever returned - the connection to the server closes when
-the file has been completely written.  Use the lower-level routines
-if multiple puts are required as it will be far more efficient.
+operations except that no server stream is ever returned - the connection
+to the server closes when the file has been completely written.  Use the
+lower-level routines if multiple puts are required as it will be far more
+efficient.
 .Sh BUGS
 I'm sure you can get this thing's internal state machine confused if
 you really work at it, but so far it's proven itself pretty robust in

lib/libftpio/ftpio.c

@@ -14,7 +14,7 @@
  * Turned inside out. Now returns xfers as new file ids, not as a special
  * `state' of FTP_t
  *
- * $Id: ftpio.c,v 1.1.1.1 1996/06/17 12:26:06 jkh Exp $
+ * $Id: ftpio.c,v 1.2 1996/06/17 12:42:33 jkh Exp $
  *
  */
 
@@ -57,7 +57,7 @@ static int	get_a_number(FTP_t ftp, char **q);
 static int	botch(char *func, char *botch_state);
 static int	cmd(FTP_t ftp, const char *fmt, ...);
 static int	ftp_login_session(FTP_t ftp, char *host, char *user, char *passwd, int port);
-static int	ftp_file_op(FTP_t ftp, char *operation, char *file, FILE **fp, char *mode);
+static int	ftp_file_op(FTP_t ftp, char *operation, char *file, FILE **fp, char *mode, int *seekto);
 static int	ftp_close(FTP_t ftp);
 static int	get_url_info(char *url_in, char *host_ret, int *port_ret, char *name_ret);
 
@@ -149,16 +149,6 @@ ftpErrno(FILE *fp)
     return ftp->errno;
 }
 
-int
-ftpRestart(FILE *fp, int where)
-{
-    FTP_t ftp = fcookie(fp);
-    int old = ftp->seek;
-
-    ftp->seek = where;
-    return old;
-}
-
 size_t
 ftpGetSize(FILE *fp, char *name)
 {
@@ -207,12 +197,12 @@ ftpGetModtime(FILE *fp, char *name)
 }
 
 FILE *
-ftpGet(FILE *fp, char *file)
+ftpGet(FILE *fp, char *file, int *seekto)
 {
     FILE *fp2;
     FTP_t ftp = fcookie(fp);
 
-    if (ftp_file_op(ftp, "RETR", file, &fp2, "r") == SUCCESS)
+    if (ftp_file_op(ftp, "RETR", file, &fp2, "r", seekto) == SUCCESS)
 	return fp2;
     return NULL;
 }
@@ -223,7 +213,7 @@ ftpPut(FILE *fp, char *file)
     FILE *fp2;
     FTP_t ftp = fcookie(fp);
 
-    if (ftp_file_op(ftp, "STOR", file, &fp2, "w") == SUCCESS)
+    if (ftp_file_op(ftp, "STOR", file, &fp2, "w", NULL) == SUCCESS)
 	return fp2;
     return NULL;
 }
@@ -256,7 +246,7 @@ ftpGetURL(char *url, char *user, char *passwd)
     if (get_url_info(url, host, &port, name) == SUCCESS) {
 	fp = ftpLogin(host, user, passwd, port);
 	if (fp) {
-	    fp2 = ftpGet(fp, name);
+	    fp2 = ftpGet(fp, name, NULL);
 	    fclose(fp);
 	    return fp2;
 	}
@@ -327,7 +317,6 @@ ftp_new(void)
     ftp->fd_ctrl = -1;
     ftp->con_state = init;
     ftp->errno = 0;
-    ftp->seek = 0;
     if (getenv("FTP_PASSIVE_MODE"))
 	ftp->passive = 1;
     return ftp;
@@ -557,7 +546,7 @@ ftp_login_session(FTP_t ftp, char *host, char *user, char *passwd, int port)
 }
 
 static int
-ftp_file_op(FTP_t ftp, char *operation, char *file, FILE **fp, char *mode)
+ftp_file_op(FTP_t ftp, char *operation, char *file, FILE **fp, char *mode, int *seekto)
 {
     int i,s;
     char *q;
@@ -610,15 +599,15 @@ ftp_file_op(FTP_t ftp, char *operation, char *file, FILE **fp, char *mode)
 	    (void)close(s);
 	    return FAILURE;
 	}
-	if (!strcmp(operation, "RETR") && ftp->seek) {
-	    i = cmd(ftp, "RETR %d", ftp->seek);
+	if (seekto && *seekto) {
+	    i = cmd(ftp, "RETR %d", *seekto);
 	    if (i < 0 || FTP_TIMEOUT(i)) {
 		close(s);
 		ftp->errno = i;
 		return i;
 	    }
 	    else if (i != 350)
-		ftp->seek = 0;
+		*seekto = 0;
 	}
 	i = cmd(ftp, "%s %s", operation, file);
 	if (i < 0 || i > 299) {
@@ -656,15 +645,15 @@ ftp_file_op(FTP_t ftp, char *operation, char *file, FILE **fp, char *mode)
 	    close(s);
 	    return i;
 	}
-	if (!strcmp(operation, "RETR") && ftp->seek) {
-	    i = cmd(ftp, "RETR %d", ftp->seek);
+	if (seekto && *seekto) {
+	    i = cmd(ftp, "RETR %d", *seekto);
 	    if (i < 0 || FTP_TIMEOUT(i)) {
 		close(s);
 		ftp->errno = i;
 		return i;
 	    }
 	    else if (i != 350)
-		ftp->seek = 0;
+		*seekto = 0;
 	}
 	i = cmd(ftp, "%s %s", operation, file);
 	if (i < 0 || i > 299) {

lib/libftpio/ftpio.h

@@ -20,7 +20,7 @@
  * Turned inside out. Now returns xfers as new file ids, not as a special
  * `state' of FTP_t
  *
- * $Id$
+ * $Id: ftpio.h,v 1.1.1.1 1996/06/17 12:26:06 jkh Exp $
  */
 
 /* Internal housekeeping data structure for FTP sessions */
@@ -33,7 +33,6 @@ typedef struct {
     char	*host;
     char	*file;
     int		errno;
-    int		seek;
 } *FTP_t;
 
 /* Exported routines - deal only with FILE* type */
@@ -41,11 +40,10 @@ extern FILE	*ftpLogin(char *host, char *user, char *passwd, int port);
 extern int	ftpChdir(FILE *fp, char *dir);
 extern int	ftpErrno(FILE *fp);
 extern size_t	ftpGetSize(FILE *fp, char *file);
-extern FILE	*ftpGet(FILE *fp, char *file);
+extern FILE	*ftpGet(FILE *fp, char *file, int *seekto);
 extern FILE	*ftpPut(FILE *fp, char *file);
 extern int	ftpBinary(FILE *fp, int status);
 extern int	ftpPassive(FILE *fp, int status);
-extern int	ftpRestart(FILE *fp, int where);
 extern FILE	*ftpGetURL(char *url, char *user, char *passwd);
 extern FILE	*ftpPutURL(char *url, char *user, char *passwd);
 extern time_t	ftpModtime(FILE *fp, char *s);