upstream: add a -X option to both scp(1) and sftp(1) to allow

control over some SFTP protocol knobs: the copy buffer length and
the number of inflight requests, both of which are used during
upload/download.

Previously these could be controlled in sftp(1) using the -b/-R options.
This makes them available in both SFTP protocol clients using the same
option character sequence.

ok dtucker@

OpenBSD-Commit-ID: 27502bffc589776f5da1f31df8cb51abe9a15f1c

scp.1

@@ -8,9 +8,9 @@
 .\"
 .\" Created: Sun May  7 00:14:37 1995 ylo
 .\"
-.\" $OpenBSD: scp.1,v 1.110 2022/09/19 21:39:16 djm Exp $
+.\" $OpenBSD: scp.1,v 1.111 2022/12/16 03:40:03 djm Exp $
 .\"
-.Dd $Mdocdate: September 19 2022 $
+.Dd $Mdocdate: December 16 2022 $
 .Dt SCP 1
 .Os
 .Sh NAME
@@ -28,6 +28,7 @@
 .Op Fl o Ar ssh_option
 .Op Fl P Ar port
 .Op Fl S Ar program
+.Op Fl X Ar sftp_option
 .Ar source ... target
 .Sh DESCRIPTION
 .Nm
@@ -278,6 +279,19 @@ and
 to print debugging messages about their progress.
 This is helpful in
 debugging connection, authentication, and configuration problems.
+.It Fl X Ar sftp_option
+Specify an option that controls aspects of SFTP protocol behaviour.
+The valid options are:
+.Bl -tag -width Ds
+.It Cm nrequests Ns = Ns Ar value
+Controls how many concurrent SFTP read or write requests may be in progress
+at any point in time during a download or upload.
+By default 64 requests may be active concurrently.
+.It Cm buffer Ns = Ns Ar value
+Controls the maximum buffer size for a single SFTP read/write operation used
+during download or upload.
+By default a 32KB buffer is used.
+.El
 .El
 .Sh EXIT STATUS
 .Ex -std scp

scp.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: scp.c,v 1.249 2022/10/24 21:51:55 djm Exp $ */
+/* $OpenBSD: scp.c,v 1.250 2022/12/16 03:40:03 djm Exp $ */
 /*
  * scp - secure remote copy.  This is basically patched BSD rcp which
  * uses ssh to do the data transfer (instead of using rcmd).
@@ -106,6 +106,9 @@
 #include <libgen.h>
 #endif
 #include <limits.h>
+#ifdef HAVE_UTIL_H
+# include <util.h>
+#endif
 #include <locale.h>
 #include <pwd.h>
 #include <signal.h>
@@ -176,6 +179,10 @@ char *ssh_program = _PATH_SSH_PROGRAM;
 pid_t do_cmd_pid = -1;
 pid_t do_cmd_pid2 = -1;
 
+/* SFTP copy parameters */
+size_t sftp_copy_buflen;
+size_t sftp_nrequests;
+
 /* Needed for sftp */
 volatile sig_atomic_t interrupted = 0;
 
@@ -444,13 +451,14 @@ void throughlocal_sftp(struct sftp_conn *, struct sftp_conn *,
 int
 main(int argc, char **argv)
 {
-	int ch, fflag, tflag, status, n;
+	int ch, fflag, tflag, status, r, n;
 	char **newargv, *argv0;
 	const char *errstr;
 	extern char *optarg;
 	extern int optind;
 	enum scp_mode_e mode = MODE_SFTP;
 	char *sftp_direct = NULL;
+	long long llv;
 
 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 	sanitise_stdfd();
@@ -480,7 +488,7 @@ main(int argc, char **argv)
 
 	fflag = Tflag = tflag = 0;
 	while ((ch = getopt(argc, argv,
-	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:")) != -1) {
+	    "12346ABCTdfOpqRrstvD:F:J:M:P:S:c:i:l:o:X:")) != -1) {
 		switch (ch) {
 		/* User-visible flags. */
 		case '1':
@@ -561,6 +569,31 @@ main(int argc, char **argv)
 			addargs(&remote_remote_args, "-q");
 			showprogress = 0;
 			break;
+		case 'X':
+			/* Please keep in sync with sftp.c -X */
+			if (strncmp(optarg, "buffer=", 7) == 0) {
+				r = scan_scaled(optarg + 7, &llv);
+				if (r == 0 && (llv <= 0 || llv > 256 * 1024)) {
+					r = -1;
+					errno = EINVAL;
+				}
+				if (r == -1) {
+					fatal("Invalid buffer size \"%s\": %s",
+					     optarg + 7, strerror(errno));
+				}
+				sftp_copy_buflen = (size_t)llv;
+			} else if (strncmp(optarg, "nrequests=", 10) == 0) {
+				llv = strtonum(optarg + 10, 1, 256 * 1024,
+				    &errstr);
+				if (errstr != NULL) {
+					fatal("Invalid number of requests "
+					    "\"%s\": %s", optarg + 10, errstr);
+				}
+				sftp_nrequests = (size_t)llv;
+			} else {
+				fatal("Invalid -X option");
+			}
+			break;
 
 		/* Server options. */
 		case 'd':
@@ -972,7 +1005,8 @@ do_sftp_connect(char *host, char *user, int port, char *sftp_direct,
 		    reminp, remoutp, pidp) < 0)
 			return NULL;
 	}
-	return do_init(*reminp, *remoutp, 32768, 64, limit_kbps);
+	return do_init(*reminp, *remoutp,
+	    sftp_copy_buflen, sftp_nrequests, limit_kbps);
 }
 
 void

sftp-client.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.c,v 1.165 2022/09/19 10:43:12 djm Exp $ */
+/* $OpenBSD: sftp-client.c,v 1.166 2022/12/16 03:40:03 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -68,10 +68,10 @@
 extern volatile sig_atomic_t interrupted;
 extern int showprogress;
 
-/* Default size of buffer for up/download */
+/* Default size of buffer for up/download (fix sftp.1 scp.1 if changed) */
 #define DEFAULT_COPY_BUFLEN	32768
 
-/* Default number of concurrent outstanding requests */
+/* Default number of concurrent xfer requests (fix sftp.1 scp.1 if changed) */
 #define DEFAULT_NUM_REQUESTS	64
 
 /* Minimum amount of data to read at a time */

sftp.1

@@ -1,4 +1,4 @@
-.\" $OpenBSD: sftp.1,v 1.142 2022/09/19 21:39:16 djm Exp $
+.\" $OpenBSD: sftp.1,v 1.143 2022/12/16 03:40:03 djm Exp $
 .\"
 .\" Copyright (c) 2001 Damien Miller.  All rights reserved.
 .\"
@@ -22,7 +22,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: September 19 2022 $
+.Dd $Mdocdate: December 16 2022 $
 .Dt SFTP 1
 .Os
 .Sh NAME
@@ -44,6 +44,7 @@
 .Op Fl R Ar num_requests
 .Op Fl S Ar program
 .Op Fl s Ar subsystem | sftp_server
+.Op Fl X Ar sftp_option
 .Ar destination
 .Sh DESCRIPTION
 .Nm
@@ -320,6 +321,19 @@ does not have an sftp subsystem configured.
 .It Fl v
 Raise logging level.
 This option is also passed to ssh.
+.It Fl X Ar sftp_option
+Specify an option that controls aspects of SFTP protocol behaviour.
+The valid options are:
+.Bl -tag -width Ds
+.It Cm nrequests Ns = Ns Ar value
+Controls how many concurrent SFTP read or write requests may be in progress
+at any point in time during a download or upload.
+By default 64 requests may be active concurrently.
+.It Cm buffer Ns = Ns Ar value
+Controls the maximum buffer size for a single SFTP read/write operation used
+during download or upload.
+By default a 32KB buffer is used.
+.El
 .El
 .Sh INTERACTIVE COMMANDS
 Once in interactive mode,

sftp.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp.c,v 1.222 2022/09/19 10:46:00 djm Exp $ */
+/* $OpenBSD: sftp.c,v 1.223 2022/12/16 03:40:03 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -2431,7 +2431,7 @@ main(int argc, char **argv)
 	struct sftp_conn *conn;
 	size_t copy_buffer_len = 0;
 	size_t num_requests = 0;
-	long long limit_kbps = 0;
+	long long llv, limit_kbps = 0;
 
 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 	sanitise_stdfd();
@@ -2449,7 +2449,7 @@ main(int argc, char **argv)
 	infile = stdin;
 
 	while ((ch = getopt(argc, argv,
-	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:")) != -1) {
+	    "1246AafhNpqrvCc:D:i:l:o:s:S:b:B:F:J:P:R:X:")) != -1) {
 		switch (ch) {
 		/* Passed through to ssh(1) */
 		case 'A':
@@ -2546,6 +2546,31 @@ main(int argc, char **argv)
 			ssh_program = optarg;
 			replacearg(&args, 0, "%s", ssh_program);
 			break;
+		case 'X':
+			/* Please keep in sync with ssh.c -X */
+			if (strncmp(optarg, "buffer=", 7) == 0) {
+				r = scan_scaled(optarg + 7, &llv);
+				if (r == 0 && (llv <= 0 || llv > 256 * 1024)) {
+					r = -1;
+					errno = EINVAL;
+				}
+				if (r == -1) {
+					fatal("Invalid buffer size \"%s\": %s",
+					     optarg + 7, strerror(errno));
+				}
+				copy_buffer_len = (size_t)llv;
+			} else if (strncmp(optarg, "nrequests=", 10) == 0) {
+				llv = strtonum(optarg + 10, 1, 256 * 1024,
+				    &errstr);
+				if (errstr != NULL) {
+					fatal("Invalid number of requests "
+					    "\"%s\": %s", optarg + 10, errstr);
+				}
+				num_requests = (size_t)llv;
+			} else {
+				fatal("Invalid -X option");
+			}
+			break;
 		case 'h':
 		default:
 			usage();