- handle case where _SC_GETPW_R_SIZE_MAX hint is too small

snapper/AppUtil.cc

@@ -324,6 +324,29 @@ namespace snapper
     }
 
 
+    bool
+    get_uid_dir(uid_t uid, string& dir)
+    {
+	struct passwd pwd;
+	struct passwd* result;
+
+	vector<char> buf(sysconf(_SC_GETPW_R_SIZE_MAX, 1024));
+
+	int e;
+	while ((e = getpwuid_r(uid, &pwd, buf.data(), buf.size(), &result)) == ERANGE)
+	    buf.resize(2 * buf.size());
+
+	if (e != 0 || result == NULL)
+	    return false;
+
+	memset(pwd.pw_passwd, 0, strlen(pwd.pw_passwd));
+
+	dir = pwd.pw_dir;
+
+	return true;
+    }
+
+
     bool
     get_user_uid(const char* username, uid_t& uid)
     {

snapper/AppUtil.h

@@ -90,9 +90,27 @@ namespace snapper
     string datetime(time_t time, bool utc, bool classic);
     time_t scan_datetime(const string& str, bool utc);
 
+    /**
+     * For the user with uid get the username (passwd.pw_name) and the gid
+     * (passwd.pw_gid).
+     */
     bool get_uid_username_gid(uid_t uid, string& username, gid_t& gid);
+
+    /**
+     * For the user with uid get the home directory (passwd.pw_dir).
+     */
+    bool get_uid_dir(uid_t uid, string& dir);
+
+    /*
+     * For the user with username get the uid (passwd.pw_uid).
+     */
     bool get_user_uid(const char* username, uid_t& uid);
+
+    /*
+     * For the group with groupname get the gid (group.gr_gid).
+     */
     bool get_group_gid(const char* groupname, gid_t& gid);
+
     vector<gid_t> getgrouplist(const char* username, gid_t gid);
 
 

snapper/Logger.cc

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) [2004-2013] Novell, Inc.
- * Copyright (c) 2018 SUSE LLC
+ * Copyright (c) [2018-2020] SUSE LLC
  *
  * All Rights Reserved.
  *
@@ -158,17 +158,11 @@ namespace snapper
 
 	if (geteuid())
 	{
-	    struct passwd pwd;
-	    struct passwd* result;
+	    string dir;
 
-	    long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
-	    char buf[bufsize];
-
-	    if (getpwuid_r(geteuid(), &pwd, buf, bufsize, &result) == 0 && result == &pwd)
+	    if (get_uid_dir(geteuid(), dir))
 	    {
-		memset(pwd.pw_passwd, 0, strlen(pwd.pw_passwd));
-
-		logger_data->filename = string(pwd.pw_dir) + "/.snapper.log";
+		logger_data->filename = dir + "/.snapper.log";
 	    }
 	}
 

testsuite-real/ug-tests.cc

@@ -23,6 +23,11 @@ test1()
     cout << "username:" << username << endl;
     cout << "gid:" << gid << endl;
 
+    string dir;
+    if (!get_uid_dir(uid, dir))
+	cerr << "failed to get dir" << endl;
+    cout << "dir:" << dir << endl;
+
     vector<gid_t> gids = getgrouplist(username.c_str(), gid);
     cout << "gids:";
     for (gid_t gid : gids)