From 7364b73e80d21b4671d696da8b05e451659f46e4 Mon Sep 17 00:00:00 2001
From: mssalvatore <mike.s.salvatore@gmail.com>
Date: Mon, 8 Apr 2019 16:50:10 -0400
Subject: Gracefully handle multiple spaces in ssh_command option (#169)

When using the "ssh_command" option, commands with multiple spaces in a
row will not be properly parsed. Example:

Properly parsed:
    ssh_command = "ssh -o IdentityFile=~/.ssh/id_rsa"

Improperly parsed:
    ssh_command = "ssh -o      IdentityFile=~/.ssh/id_rsa"

This commit changes the ssh_command parsing logic so that both of the
above examples are considered valid and properly handled.

Fixes: #114.
---
 ChangeLog.rst |  1 +
 sshfs.c       | 78 +++++++++++++++++++++++++++++++++++++----------------------
 2 files changed, 50 insertions(+), 29 deletions(-)

diff --git a/ChangeLog.rst b/ChangeLog.rst
index 7e88754..c5468b4 100644
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -2,6 +2,7 @@ Unreleased Changes
 ------------------
 
 * Fixed "-o idmap=user" to map both UID and GID on all OSs.
+* Fixed improper handling of sequential spaces spaces in "ssh_command" option
 
 Release 3.5.1 (2018-12-22)
 --------------------------
diff --git a/sshfs.c b/sshfs.c
index 6919515..06a1ef3 100644
--- a/sshfs.c
+++ b/sshfs.c
@@ -3596,40 +3596,60 @@ static int read_password(void)
 	return 0;
 }
 
+// Behaves similarly to strtok(), but allows for the ' ' delimiter to be escaped
+// by '\ '.
+static char *tokenize_on_space(char *str)
+{
+	static char *pos = NULL;
+	char *start = NULL;
+
+	if (str)
+		pos = str;
+
+	if (!pos)
+		return NULL;
+
+	// trim any leading spaces
+	while (*pos == ' ')
+		pos++;
+
+	start = pos;
+
+	while (pos && *pos != '\0') {
+		// break on space, but not on '\ '
+		if (*pos == ' ' && *(pos - 1) != '\\') {
+			break;
+		}
+		pos++;
+	}
+
+	if (*pos == '\0') {
+		pos = NULL;
+	}
+	else {
+		*pos = '\0';
+		pos++;
+	}
+
+	return start;
+}
+
 static void set_ssh_command(void)
 {
-	char *s;
-	char *d;
+	char *token = NULL;
 	int i = 0;
-	int end = 0;
-
-	d = sshfs.ssh_command;
-	s = sshfs.ssh_command;
-	while (!end) {
-		switch (*s) {
-		case '\0':
-			end = 1;
-		case ' ':
-			*d = '\0';
-			if (i == 0) {
-				replace_arg(&sshfs.ssh_args.argv[0],
-					    sshfs.ssh_command);
-			} else {
-				if (fuse_opt_insert_arg(&sshfs.ssh_args, i,
-						sshfs.ssh_command) == -1)
-					_exit(1);
-			}
-			i++;
-			d = sshfs.ssh_command;
-			break;
 
-		case '\\':
-			if (s[1])
-				s++;
-		default:
-			*d++ = *s;
+	token = tokenize_on_space(sshfs.ssh_command);
+	while (token != NULL) {
+		if (i == 0) {
+			replace_arg(&sshfs.ssh_args.argv[0], token);
+		} else {
+			if (fuse_opt_insert_arg(&sshfs.ssh_args, i, token) == -1)
+				_exit(1);
 		}
-		s++;
+		i++;
+
+		token = tokenize_on_space(NULL);
 	}
 }
 
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