First attempt at a Unix port of Plink. Seems to basically work;

doesn't yet use the SSH agent, no way to specify arbitrary config
options, no manpage yet, couple of other fiddly things need doing,
but it makes SSH connections and doesn't fall over horribly so I say
it's a good start. Now to run it under valgrind...

[originally from svn r2165]

unix/uxstore.c

@@ -6,9 +6,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
-#include <gtk/gtk.h>
-#include <gdk/gdkx.h>
-#include <X11/Xlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include "putty.h"
 #include "storage.h"
 #include "tree234.h"
@@ -46,8 +47,6 @@ void close_settings_w(void *handle)
  * immediately work out.
  */
 
-static Display *display;
-
 struct xrm_string {
     char *key;
     char *value;
@@ -104,17 +103,13 @@ char *get_setting(char *key)
 	if (ret)
 	    return ret->value;
     }
-    return XGetDefault(display, app_name, key);
+    return x_get_default(key);
 }
 
 void *open_settings_r(char *sessionname)
 {
     static int thing_to_return_an_arbitrary_non_null_pointer_to;
-    display = GDK_DISPLAY();
-    if (!display)
-	return NULL;
-    else
-	return &thing_to_return_an_arbitrary_non_null_pointer_to;
+    return &thing_to_return_an_arbitrary_non_null_pointer_to;
 }
 
 char *read_setting_s(void *handle, char *key, char *buffer, int buflen)
@@ -160,13 +155,144 @@ void enum_settings_finish(void *handle)
 {
 }
 
+enum {
+    INDEX_DIR, INDEX_HOSTKEYS
+};
+
+static void make_filename(char *filename, int index)
+{
+    char *home;
+    int len;
+    home = getenv("HOME");
+    strncpy(filename, home, FILENAME_MAX);
+    len = strlen(filename);
+    strncpy(filename + len,
+	    index == INDEX_DIR ? "/.putty" :
+	    index == INDEX_HOSTKEYS ? "/.putty/sshhostkeys" :
+	    "/.putty/ERROR", FILENAME_MAX - len);
+    filename[FILENAME_MAX-1] = '\0';
+}
+
+/*
+ * Read an entire line of text from a file. Return a buffer
+ * malloced to be as big as necessary (caller must free).
+ */
+static char *fgetline(FILE *fp)
+{
+    char *ret = smalloc(512);
+    int size = 512, len = 0;
+    while (fgets(ret + len, size - len, fp)) {
+	len += strlen(ret + len);
+	if (ret[len-1] == '\n')
+	    break;		       /* got a newline, we're done */
+	size = len + 512;
+	ret = srealloc(ret, size);
+    }
+    if (len == 0) {		       /* first fgets returned NULL */
+	sfree(ret);
+	return NULL;
+    }
+    ret[len] = '\0';
+    return ret;
+}
+
+/*
+ * Lines in the host keys file are of the form
+ * 
+ *   type@port:hostname keydata
+ * 
+ * e.g.
+ * 
+ *   rsa@22:foovax.example.org 0x23,0x293487364395345345....2343
+ */
 int verify_host_key(char *hostname, int port, char *keytype, char *key)
 {
-    return 1;			       /* key does not exist in registry */
+    FILE *fp;
+    char filename[FILENAME_MAX];
+    char *line;
+    int ret;
+
+    make_filename(filename, INDEX_HOSTKEYS);
+    fp = fopen(filename, "r");
+    if (!fp)
+	return 1;		       /* key does not exist */
+
+    ret = 1;
+    while ( (line = fgetline(fp)) ) {
+	int i;
+	char *p = line;
+	char porttext[20];
+
+	line[strcspn(line, "\n")] = '\0';   /* strip trailing newline */
+
+	i = strlen(keytype);
+	if (strncmp(p, keytype, i))
+	    goto done;
+	p += i;
+
+	if (*p != '@')
+	    goto done;
+	p++;
+
+	sprintf(porttext, "%d", port);
+	i = strlen(porttext);
+	if (strncmp(p, porttext, i))
+	    goto done;
+	p += i;
+
+	if (*p != ':')
+	    goto done;
+	p++;
+
+	i = strlen(hostname);
+	if (strncmp(p, hostname, i))
+	    goto done;
+	p += i;
+
+	if (*p != ' ')
+	    goto done;
+	p++;
+
+	/*
+	 * Found the key. Now just work out whether it's the right
+	 * one or not.
+	 */
+	if (!strcmp(p, key))
+	    ret = 0;		       /* key matched OK */
+	else
+	    ret = 2;		       /* key mismatch */
+
+	done:
+	sfree(line);
+	if (ret != 1)
+	    break;
+    }
+
+    return ret;
 }
 
 void store_host_key(char *hostname, int port, char *keytype, char *key)
 {
+    FILE *fp;
+    int fd;
+    char filename[FILENAME_MAX];
+
+    make_filename(filename, INDEX_HOSTKEYS);
+    fd = open(filename, O_CREAT | O_APPEND | O_RDWR, 0600);
+    if (fd < 0) {
+	char dir[FILENAME_MAX];
+
+	make_filename(dir, INDEX_DIR);
+	mkdir(dir, 0700);
+	fd = open(filename, O_CREAT | O_APPEND | O_RDWR, 0600);
+    }
+    if (fd < 0) {
+	perror(filename);
+	exit(1);
+    }
+    fp = fdopen(fd, "a");
+    fprintf(fp, "%s@%d:%s %s\n", keytype, port, hostname, key);
+    fclose(fp);
 }
 
 void read_random_seed(noise_consumer_t consumer)