misc: Cache user home directory in session

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

include/libssh/misc.h

@@ -43,7 +43,7 @@ extern "C" {
 
 /* in misc.c */
 /* gets the user home dir. */
-char *ssh_get_user_home_dir(void);
+char *ssh_get_user_home_dir(ssh_session session);
 char *ssh_get_local_username(void);
 int ssh_file_readaccess_ok(const char *file);
 int ssh_dir_writeable(const char *path);

include/libssh/session.h

@@ -253,6 +253,7 @@ struct ssh_session_struct {
         char *username;
         char *host;
         char *bindaddr; /* bind the client to an ip addr */
+        char *homedir;
         char *sshdir;
         char *knownhosts;
         char *global_knownhosts;

src/misc.c

@@ -108,7 +108,7 @@
  */
 
 #ifdef _WIN32
-char *ssh_get_user_home_dir(void)
+static char *ssh_get_user_home_dir_internal(void)
 {
     char tmp[PATH_MAX] = {0};
     char *szPath = NULL;
@@ -298,7 +298,7 @@ int ssh_is_ipaddr(const char *str)
 #define NSS_BUFLEN_PASSWD 4096
 #endif /* NSS_BUFLEN_PASSWD */
 
-char *ssh_get_user_home_dir(void)
+static char *ssh_get_user_home_dir_internal(void)
 {
     char *szPath = NULL;
     struct passwd pwd;
@@ -313,7 +313,6 @@ char *ssh_get_user_home_dir(void)
             return NULL;
         }
         snprintf(buf, sizeof(buf), "%s", szPath);
-
         return strdup(buf);
     }
 
@@ -428,6 +427,29 @@ int ssh_is_ipaddr(const char *str)
 
 #endif /* _WIN32 */
 
+char *ssh_get_user_home_dir(ssh_session session)
+{
+    char *szPath = NULL;
+
+    /* If used previously, reuse cached value */
+    if (session != NULL && session->opts.homedir != NULL) {
+        return strdup(session->opts.homedir);
+    }
+
+    szPath = ssh_get_user_home_dir_internal();
+    if (szPath == NULL) {
+        return NULL;
+    }
+
+    if (session != NULL) {
+        /* cache it:
+         * failure is not fatal -- at worst we will just not cache it */
+        session->opts.homedir = strdup(szPath);
+    }
+
+    return szPath;
+}
+
 char *ssh_lowercase(const char* str)
 {
     char *new = NULL, *p = NULL;
@@ -1189,7 +1211,7 @@ char *ssh_path_expand_tilde(const char *d)
     } else {
         ld = strlen(d);
         p = (char *) d;
-        h = ssh_get_user_home_dir();
+        h = ssh_get_user_home_dir(NULL);
     }
     if (h == NULL) {
         return NULL;

src/session.c

@@ -405,6 +405,7 @@ void ssh_free(ssh_session session)
   SAFE_FREE(session->opts.bindaddr);
   SAFE_FREE(session->opts.username);
   SAFE_FREE(session->opts.host);
+  SAFE_FREE(session->opts.homedir);
   SAFE_FREE(session->opts.sshdir);
   SAFE_FREE(session->opts.knownhosts);
   SAFE_FREE(session->opts.global_knownhosts);

tests/unittests/torture_misc.c

@@ -52,7 +52,7 @@ static void torture_get_user_home_dir(void **state) {
 
     (void) state;
 
-    user = ssh_get_user_home_dir();
+    user = ssh_get_user_home_dir(NULL);
     assert_non_null(user);
 #ifndef _WIN32
     assert_string_equal(user, pwd->pw_dir);