Merge pull request #6455 from libgit2/ethomson/sysdir

Support the notion of a home directory separately from global configuration directory

10 files changed, 408 insertions, 384 deletions

diff --git a/src/libgit2/attrcache.c b/src/libgit2/attrcache.c
index b16d95c3c..405944ed1 100644
--- a/src/libgit2/attrcache.c
+++ b/src/libgit2/attrcache.c
@@ -300,7 +300,7 @@ static int attr_cache__lookup_path(
 
 		/* expand leading ~/ as needed */
 		if (cfgval && cfgval[0] == '~' && cfgval[1] == '/') {
-			if (! (error = git_sysdir_expand_global_file(&buf, &cfgval[2])))
+			if (! (error = git_sysdir_expand_homedir_file(&buf, &cfgval[2])))
 				*out = git_str_detach(&buf);
 		} else if (cfgval) {
 			*out = git__strdup(cfgval);
diff --git a/src/libgit2/config.c b/src/libgit2/config.c
index 5c366e221..6d15a8db6 100644
--- a/src/libgit2/config.c
+++ b/src/libgit2/config.c
@@ -860,7 +860,7 @@ static int git_config__parse_path(git_str *out, const char *value)
 			return -1;
 		}
 
-		return git_sysdir_expand_global_file(out, value[1] ? &value[2] : NULL);
+		return git_sysdir_expand_homedir_file(out, value[1] ? &value[2] : NULL);
 	}
 
 	return git_str_sets(out, value);
diff --git a/src/libgit2/config_file.c b/src/libgit2/config_file.c
index 66fcb8ae2..932ca7601 100644
--- a/src/libgit2/config_file.c
+++ b/src/libgit2/config_file.c
@@ -528,7 +528,7 @@ static int included_path(git_str *out, const char *dir, const char *path)
 {
 	/* From the user's home */
 	if (path[0] == '~' && path[1] == '/')
-		return git_sysdir_expand_global_file(out, &path[1]);
+		return git_sysdir_expand_homedir_file(out, &path[1]);
 
 	return git_fs_path_join_unrooted(out, path, dir, NULL);
 }
@@ -616,7 +616,7 @@ static int do_match_gitdir(
 		git_fs_path_dirname_r(&pattern, cfg_file);
 		git_str_joinpath(&pattern, pattern.ptr, condition + 2);
 	} else if (condition[0] == '~' && git_fs_path_is_dirsep(condition[1]))
-		git_sysdir_expand_global_file(&pattern, condition + 1);
+		git_sysdir_expand_homedir_file(&pattern, condition + 1);
 	else if (!git_fs_path_is_absolute(condition))
 		git_str_joinpath(&pattern, "**", condition);
 	else
diff --git a/src/libgit2/libgit2.c b/src/libgit2/libgit2.c
index 2fda0722e..f225122e5 100644
--- a/src/libgit2/libgit2.c
+++ b/src/libgit2/libgit2.c
@@ -414,6 +414,25 @@ int git_libgit2_opts(int key, ...)
 		git_repository__validate_ownership = (va_arg(ap, int) != 0);
 		break;
 
+	case GIT_OPT_GET_HOMEDIR:
+		{
+			git_buf *out = va_arg(ap, git_buf *);
+			git_str str = GIT_STR_INIT;
+			const git_str *tmp;
+
+			if ((error = git_buf_tostr(&str, out)) < 0 ||
+			    (error = git_sysdir_get(&tmp, GIT_SYSDIR_HOME)) < 0 ||
+			    (error = git_str_put(&str, tmp->ptr, tmp->size)) < 0)
+				break;
+
+			error = git_buf_fromstr(out, &str);
+		}
+		break;
+
+	case GIT_OPT_SET_HOMEDIR:
+		error = git_sysdir_set(GIT_SYSDIR_HOME, va_arg(ap, const char *));
+		break;
+
 	default:
 		git_error_set(GIT_ERROR_INVALID, "invalid option key");
 		error = -1;
diff --git a/src/libgit2/sysdir.c b/src/libgit2/sysdir.c
index 450cb509b..7838a6789 100644
--- a/src/libgit2/sysdir.c
+++ b/src/libgit2/sysdir.c
@@ -12,16 +12,262 @@
 #include "fs_path.h"
 #include <ctype.h>
 #if GIT_WIN32
-#include "win32/findfile.h"
+# include "fs_path.h"
+# include "win32/path_w32.h"
+# include "win32/utf-conv.h"
 #else
-#include <unistd.h>
-#include <pwd.h>
+# include <unistd.h>
+# include <pwd.h>
 #endif
 
+#ifdef GIT_WIN32
+# define REG_GITFORWINDOWS_KEY       L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"
+# define REG_GITFORWINDOWS_KEY_WOW64 L"SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"
+
+static int expand_win32_path(git_win32_path dest, const wchar_t *src)
+{
+	DWORD len = ExpandEnvironmentStringsW(src, dest, GIT_WIN_PATH_UTF16);
+
+	if (!len || len > GIT_WIN_PATH_UTF16)
+		return -1;
+
+	return 0;
+}
+
+static int win32_path_to_utf8(git_str *dest, const wchar_t *src)
+{
+	git_win32_utf8_path utf8_path;
+
+	if (git_win32_path_to_utf8(utf8_path, src) < 0) {
+		git_error_set(GIT_ERROR_OS, "unable to convert path to UTF-8");
+		return -1;
+	}
+
+	/* Convert backslashes to forward slashes */
+	git_fs_path_mkposix(utf8_path);
+
+	return git_str_sets(dest, utf8_path);
+}
+
+static git_win32_path mock_registry;
+static bool mock_registry_set;
+
+extern int git_win32__set_registry_system_dir(const wchar_t *mock_sysdir)
+{
+	if (!mock_sysdir) {
+		mock_registry[0] = L'\0';
+		mock_registry_set = false;
+	} else {
+		size_t len = wcslen(mock_sysdir);
+
+		if (len > GIT_WIN_PATH_MAX) {
+			git_error_set(GIT_ERROR_INVALID, "mock path too long");
+			return -1;
+		}
+
+		wcscpy(mock_registry, mock_sysdir);
+		mock_registry_set = true;
+	}
+
+	return 0;
+}
+
+static int lookup_registry_key(
+	git_win32_path out,
+	const HKEY hive,
+	const wchar_t* key,
+	const wchar_t *value)
+{
+	HKEY hkey;
+	DWORD type, size;
+	int error = GIT_ENOTFOUND;
+
+	/*
+	 * Registry data may not be NUL terminated, provide room to do
+	 * it ourselves.
+	 */
+	size = (DWORD)((sizeof(git_win32_path) - 1) * sizeof(wchar_t));
+
+	if (RegOpenKeyExW(hive, key, 0, KEY_READ, &hkey) != 0)
+		return GIT_ENOTFOUND;
+
+	if (RegQueryValueExW(hkey, value, NULL, &type, (LPBYTE)out, &size) == 0 &&
+	    type == REG_SZ &&
+	    size > 0 &&
+	    size < sizeof(git_win32_path)) {
+		size_t wsize = size / sizeof(wchar_t);
+		size_t len = wsize - 1;
+
+		if (out[wsize - 1] != L'\0') {
+			len = wsize;
+			out[wsize] = L'\0';
+		}
+
+		if (out[len - 1] == L'\\')
+			out[len - 1] = L'\0';
+
+		if (_waccess(out, F_OK) == 0)
+			error = 0;
+	}
+
+	RegCloseKey(hkey);
+	return error;
+}
+
+static int find_sysdir_in_registry(git_win32_path out)
+{
+	if (mock_registry_set) {
+		if (mock_registry[0] == L'\0')
+			return GIT_ENOTFOUND;
+
+		wcscpy(out, mock_registry);
+		return 0;
+	}
+
+	if (lookup_registry_key(out, HKEY_CURRENT_USER, REG_GITFORWINDOWS_KEY, L"InstallLocation") == 0 ||
+	    lookup_registry_key(out, HKEY_CURRENT_USER, REG_GITFORWINDOWS_KEY_WOW64, L"InstallLocation") == 0 ||
+	    lookup_registry_key(out, HKEY_LOCAL_MACHINE, REG_GITFORWINDOWS_KEY, L"InstallLocation") == 0 ||
+	    lookup_registry_key(out, HKEY_LOCAL_MACHINE, REG_GITFORWINDOWS_KEY_WOW64, L"InstallLocation") == 0)
+		return 0;
+
+    return GIT_ENOTFOUND;
+}
+
+static int find_sysdir_in_path(git_win32_path out)
+{
+	size_t out_len;
+
+	if (git_win32_path_find_executable(out, L"git.exe") < 0 &&
+	    git_win32_path_find_executable(out, L"git.cmd") < 0)
+		return GIT_ENOTFOUND;
+
+	out_len = wcslen(out);
+
+	/* Trim the file name */
+	if (out_len <= CONST_STRLEN(L"git.exe"))
+		return GIT_ENOTFOUND;
+
+	out_len -= CONST_STRLEN(L"git.exe");
+
+	if (out_len && out[out_len - 1] == L'\\')
+		out_len--;
+
+	/*
+	 * Git for Windows usually places the command in a 'bin' or
+	 * 'cmd' directory, trim that.
+	 */
+	if (out_len >= CONST_STRLEN(L"\\bin") &&
+	    wcsncmp(&out[out_len - CONST_STRLEN(L"\\bin")], L"\\bin", CONST_STRLEN(L"\\bin")) == 0)
+		out_len -= CONST_STRLEN(L"\\bin");
+	else if (out_len >= CONST_STRLEN(L"\\cmd") &&
+	         wcsncmp(&out[out_len - CONST_STRLEN(L"\\cmd")], L"\\cmd", CONST_STRLEN(L"\\cmd")) == 0)
+		out_len -= CONST_STRLEN(L"\\cmd");
+
+	if (!out_len)
+		return GIT_ENOTFOUND;
+
+	out[out_len] = L'\0';
+	return 0;
+}
+
+static int find_win32_dirs(
+    git_str *out,
+    const wchar_t* tmpl[])
+{
+	git_win32_path path16;
+	git_str buf = GIT_STR_INIT;
+
+	git_str_clear(out);
+
+	for (; *tmpl != NULL; tmpl++) {
+		if (!expand_win32_path(path16, *tmpl) &&
+		    path16[0] != L'%' &&
+		    !_waccess(path16, F_OK)) {
+			win32_path_to_utf8(&buf, path16);
+
+			if (buf.size)
+				git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);
+		}
+	}
+
+	git_str_dispose(&buf);
+
+	return (git_str_oom(out) ? -1 : 0);
+}
+
+static int append_subdir(git_str *out, git_str *path, const char *subdir)
+{
+	static const char* architecture_roots[] = {
+		"",
+		"mingw64",
+		"mingw32",
+		NULL
+	};
+	const char **root;
+	size_t orig_path_len = path->size;
+
+	for (root = architecture_roots; *root; root++) {
+		if ((*root[0] && git_str_joinpath(path, path->ptr, *root) < 0) ||
+		    git_str_joinpath(path, path->ptr, subdir) < 0)
+			return -1;
+
+		if (git_fs_path_exists(path->ptr) &&
+		    git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, path->ptr) < 0)
+			return -1;
+
+		git_str_truncate(path, orig_path_len);
+	}
+
+	return 0;
+}
+
+int git_win32__find_system_dirs(git_str *out, const char *subdir)
+{
+	git_win32_path pathdir, regdir;
+	git_str path8 = GIT_STR_INIT;
+	bool has_pathdir, has_regdir;
+	int error;
+
+	has_pathdir = (find_sysdir_in_path(pathdir) == 0);
+	has_regdir = (find_sysdir_in_registry(regdir) == 0);
+
+	if (!has_pathdir && !has_regdir)
+		return 0;
+
+	/*
+	 * Usually the git in the path is the same git in the registry,
+	 * in this case there's no need to duplicate the paths.
+	 */
+	if (has_pathdir && has_regdir && wcscmp(pathdir, regdir) == 0)
+		has_regdir = false;
+
+	if (has_pathdir) {
+		if ((error = win32_path_to_utf8(&path8, pathdir)) < 0 ||
+		    (error = append_subdir(out, &path8, subdir)) < 0)
+			goto done;
+	}
+
+	if (has_regdir) {
+		if ((error = win32_path_to_utf8(&path8, regdir)) < 0 ||
+		    (error = append_subdir(out, &path8, subdir)) < 0)
+			goto done;
+	}
+
+done:
+    git_str_dispose(&path8);
+    return error;
+}
+#endif /* WIN32 */
+
 static int git_sysdir_guess_programdata_dirs(git_str *out)
 {
 #ifdef GIT_WIN32
-	return git_win32__find_programdata_dirs(out);
+	static const wchar_t *programdata_tmpls[2] = {
+		L"%PROGRAMDATA%\\Git",
+		NULL,
+	};
+
+	return find_win32_dirs(out, programdata_tmpls);
 #else
 	git_str_clear(out);
 	return 0;
@@ -75,10 +321,17 @@ out:
 }
 #endif
 
-static int git_sysdir_guess_global_dirs(git_str *out)
+static int git_sysdir_guess_home_dirs(git_str *out)
 {
 #ifdef GIT_WIN32
-	return git_win32__find_global_dirs(out);
+	static const wchar_t *global_tmpls[4] = {
+		L"%HOME%\\",
+		L"%HOMEDRIVE%%HOMEPATH%\\",
+		L"%USERPROFILE%\\",
+		NULL,
+	};
+
+	return find_win32_dirs(out, global_tmpls);
 #else
 	int error;
 	uid_t uid, euid;
@@ -114,10 +367,25 @@ static int git_sysdir_guess_global_dirs(git_str *out)
 #endif
 }
 
+static int git_sysdir_guess_global_dirs(git_str *out)
+{
+	return git_sysdir_guess_home_dirs(out);
+}
+
 static int git_sysdir_guess_xdg_dirs(git_str *out)
 {
 #ifdef GIT_WIN32
-	return git_win32__find_xdg_dirs(out);
+	static const wchar_t *global_tmpls[7] = {
+		L"%XDG_CONFIG_HOME%\\git",
+		L"%APPDATA%\\git",
+		L"%LOCALAPPDATA%\\git",
+		L"%HOME%\\.config\\git",
+		L"%HOMEDRIVE%%HOMEPATH%\\.config\\git",
+		L"%USERPROFILE%\\.config\\git",
+		NULL,
+	};
+
+	return find_win32_dirs(out, global_tmpls);
 #else
 	git_str env = GIT_STR_INIT;
 	int error;
@@ -171,6 +439,7 @@ static struct git_sysdir__dir git_sysdir__dirs[] = {
 	{ GIT_STR_INIT, git_sysdir_guess_xdg_dirs },
 	{ GIT_STR_INIT, git_sysdir_guess_programdata_dirs },
 	{ GIT_STR_INIT, git_sysdir_guess_template_dirs },
+	{ GIT_STR_INIT, git_sysdir_guess_home_dirs }
 };
 
 static void git_sysdir_global_shutdown(void)
@@ -350,6 +619,12 @@ int git_sysdir_find_template_dir(git_str *path)
 		path, NULL, GIT_SYSDIR_TEMPLATE, "template");
 }
 
+int git_sysdir_find_homedir(git_str *path)
+{
+	return git_sysdir_find_in_dirlist(
+		path, NULL, GIT_SYSDIR_HOME, "home directory");
+}
+
 int git_sysdir_expand_global_file(git_str *path, const char *filename)
 {
 	int error;
@@ -361,3 +636,15 @@ int git_sysdir_expand_global_file(git_str *path, const char *filename)
 
 	return error;
 }
+
+int git_sysdir_expand_homedir_file(git_str *path, const char *filename)
+{
+	int error;
+
+	if ((error = git_sysdir_find_homedir(path)) == 0) {
+		if (filename)
+			error = git_str_joinpath(path, path->ptr, filename);
+	}
+
+	return error;
+}
diff --git a/src/libgit2/sysdir.h b/src/libgit2/sysdir.h
index 568f27940..1d15bbf43 100644
--- a/src/libgit2/sysdir.h
+++ b/src/libgit2/sysdir.h
@@ -57,10 +57,22 @@ extern int git_sysdir_find_programdata_file(git_str *path, const char *filename)
 extern int git_sysdir_find_template_dir(git_str *path);
 
 /**
- * Expand the name of a "global" file (i.e. one in a user's home
- * directory).  Unlike `find_global_file` (above), this makes no
- * attempt to check for the existence of the file, and is useful if
- * you want the full path regardless of existence.
+ * Find the home directory. On Windows, this will look at the `HOME`,
+ * `HOMEPATH`, and `USERPROFILE` environment variables (in that order)
+ * and return the first path that is set and exists. On other systems,
+ * this will simply return the contents of the `HOME` environment variable.
+ *
+ * @param path buffer to write the full path into
+ * @return 0 if found, GIT_ENOTFOUND if not found, or -1 on other OS error
+ */
+extern int git_sysdir_find_homedir(git_str *path);
+
+/**
+ * Expand the name of a "global" file -- by default inside the user's
+ * home directory, but can be overridden by the user configuration.
+ * Unlike `find_global_file` (above), this makes no attempt to check
+ * for the existence of the file, and is useful if you want the full
+ * path regardless of existence.
  *
  * @param path buffer to write the full path into
  * @param filename name of file in the home directory
@@ -68,13 +80,25 @@ extern int git_sysdir_find_template_dir(git_str *path);
  */
 extern int git_sysdir_expand_global_file(git_str *path, const char *filename);
 
+/**
+ * Expand the name of a file in the user's home directory. This
+ * function makes no attempt to check for the existence of the file,
+ * and is useful if you want the full path regardless of existence.
+ *
+ * @param path buffer to write the full path into
+ * @param filename name of file in the home directory
+ * @return 0 on success or -1 on error
+ */
+extern int git_sysdir_expand_homedir_file(git_str *path, const char *filename);
+
 typedef enum {
-	GIT_SYSDIR_SYSTEM = 0,
-	GIT_SYSDIR_GLOBAL = 1,
-	GIT_SYSDIR_XDG    = 2,
+	GIT_SYSDIR_SYSTEM      = 0,
+	GIT_SYSDIR_GLOBAL      = 1,
+	GIT_SYSDIR_XDG         = 2,
 	GIT_SYSDIR_PROGRAMDATA = 3,
-	GIT_SYSDIR_TEMPLATE = 4,
-	GIT_SYSDIR__MAX   = 5
+	GIT_SYSDIR_TEMPLATE    = 4,
+	GIT_SYSDIR_HOME        = 5,
+	GIT_SYSDIR__MAX        = 6
 } git_sysdir_t;
 
 /**
@@ -110,4 +134,10 @@ extern int git_sysdir_set(git_sysdir_t which, const char *paths);
  */
 extern int git_sysdir_reset(void);
 
+/** Sets the registry system dir to a mock; for testing.  */
+extern int git_win32__set_registry_system_dir(const wchar_t *mock_sysdir);
+
+/** Find the given system dir; for testing. */
+extern int git_win32__find_system_dirs(git_str *out, const char *subdir);
+
 #endif
diff --git a/src/libgit2/transports/ssh.c b/src/libgit2/transports/ssh.c
index 85e779744..e90ab07e8 100644
--- a/src/libgit2/transports/ssh.c
+++ b/src/libgit2/transports/ssh.c
@@ -16,6 +16,7 @@
 #include "netops.h"
 #include "smart.h"
 #include "streams/socket.h"
+#include "sysdir.h"
 
 #include "git2/credential.h"
 #include "git2/sys/credential.h"
@@ -421,7 +422,8 @@ static int request_creds(git_credential **out, ssh_subtransport *t, const char *
 	return 0;
 }
 
-#define KNOWN_HOSTS_FILE ".ssh/known_hosts"
+#define SSH_DIR          ".ssh"
+#define KNOWN_HOSTS_FILE "known_hosts"
 
 /*
  * Load the known_hosts file.
@@ -430,16 +432,14 @@ static int request_creds(git_credential **out, ssh_subtransport *t, const char *
  */
 static int load_known_hosts(LIBSSH2_KNOWNHOSTS **hosts, LIBSSH2_SESSION *session)
 {
-	git_str path = GIT_STR_INIT, home = GIT_STR_INIT;
+	git_str path = GIT_STR_INIT, sshdir = GIT_STR_INIT;
 	LIBSSH2_KNOWNHOSTS *known_hosts = NULL;
 	int error;
 
 	GIT_ASSERT_ARG(hosts);
 
-	if ((error = git__getenv(&home, "HOME")) < 0)
-		return error;
-
-	if ((error = git_str_joinpath(&path, git_str_cstr(&home), KNOWN_HOSTS_FILE)) < 0)
+	if ((error = git_sysdir_expand_homedir_file(&sshdir, SSH_DIR)) < 0 ||
+	    (error = git_str_joinpath(&path, git_str_cstr(&sshdir), KNOWN_HOSTS_FILE)) < 0)
 		goto out;
 
 	if ((known_hosts = libssh2_knownhost_init(session)) == NULL) {
@@ -461,34 +461,32 @@ static int load_known_hosts(LIBSSH2_KNOWNHOSTS **hosts, LIBSSH2_SESSION *session
 out:
 	*hosts = known_hosts;
 
-	git_str_clear(&home);
-	git_str_clear(&path);
+	git_str_dispose(&sshdir);
+	git_str_dispose(&path);
 
 	return error;
 }
 
-static const char *hostkey_type_to_string(int type)
+static void add_hostkey_pref_if_avail(
+	LIBSSH2_KNOWNHOSTS *known_hosts,
+	const char *hostname,
+	int port,
+	git_str *prefs,
+	int type,
+	const char *type_name)
 {
-	switch (type) {
-	case LIBSSH2_KNOWNHOST_KEY_SSHRSA:
-		return "ssh-rsa";
-	case LIBSSH2_KNOWNHOST_KEY_SSHDSS:
-		return "ssh-dss";
-#ifdef LIBSSH2_KNOWNHOST_KEY_ECDSA_256
-	case LIBSSH2_KNOWNHOST_KEY_ECDSA_256:
-		return "ecdsa-sha2-nistp256";
-	case LIBSSH2_KNOWNHOST_KEY_ECDSA_384:
-		return "ecdsa-sha2-nistp384";
-	case LIBSSH2_KNOWNHOST_KEY_ECDSA_521:
-		return "ecdsa-sha2-nistp521";
-#endif
-#ifdef LIBSSH2_KNOWNHOST_KEY_ED25519
-	case LIBSSH2_KNOWNHOST_KEY_ED25519:
-		return "ssh-ed25519";
-#endif
-	}
+	struct libssh2_knownhost *host = NULL;
+	const char key = '\0';
+	int mask = LIBSSH2_KNOWNHOST_TYPE_PLAIN | LIBSSH2_KNOWNHOST_KEYENC_RAW | type;
+	int error;
 
-	return NULL;
+	error = libssh2_knownhost_checkp(known_hosts, hostname, port, &key, 1, mask, &host);
+	if (error == LIBSSH2_KNOWNHOST_CHECK_MISMATCH) {
+		if (git_str_len(prefs) > 0) {
+			git_str_putc(prefs, ',');
+		}
+		git_str_puts(prefs, type_name);
+	}
 }
 
 /*
@@ -496,27 +494,27 @@ static const char *hostkey_type_to_string(int type)
  * look it up with a nonsense key and using that mismatch to figure out what key
  * we do have stored for the host.
  *
- * Returns the string to pass to libssh2_session_method_pref or NULL if we were
- * unable to find anything or an error happened.
+ * Populates prefs with the string to pass to libssh2_session_method_pref.
  */
-static const char *find_hostkey_preference(LIBSSH2_KNOWNHOSTS *known_hosts, const char *hostname, int port)
+static void find_hostkey_preference(
+	LIBSSH2_KNOWNHOSTS *known_hosts,
+	const char *hostname,
+	int port,
+	git_str *prefs)
 {
-	struct libssh2_knownhost *host = NULL;
-	/* Specify no key type so we don't filter on that */
-	int type = LIBSSH2_KNOWNHOST_TYPE_PLAIN | LIBSSH2_KNOWNHOST_KEYENC_RAW;
-	const char key = '\0';
-	int error;
-
 	/*
-	 * In case of mismatch, we can find the type of key from known_hosts in
-	 * the returned host's information as it means that an entry was found
-	 * but our nonsense key obviously didn't match.
+	 * The order here is important as it indicates the priority of what will
+	 * be preferred.
 	 */
-	error = libssh2_knownhost_checkp(known_hosts, hostname, port, &key, 1, type, &host);
-	if (error == LIBSSH2_KNOWNHOST_CHECK_MISMATCH)
-		return hostkey_type_to_string(host->typemask & LIBSSH2_KNOWNHOST_KEY_MASK);
-
-	return NULL;
+#ifdef LIBSSH2_KNOWNHOST_KEY_ED25519
+	add_hostkey_pref_if_avail(known_hosts, hostname, port, prefs, LIBSSH2_KNOWNHOST_KEY_ED25519, "ssh-ed25519");
+#endif
+#ifdef LIBSSH2_KNOWNHOST_KEY_ECDSA_256
+	add_hostkey_pref_if_avail(known_hosts, hostname, port, prefs, LIBSSH2_KNOWNHOST_KEY_ECDSA_256, "ecdsa-sha2-nistp256");
+	add_hostkey_pref_if_avail(known_hosts, hostname, port, prefs, LIBSSH2_KNOWNHOST_KEY_ECDSA_384, "ecdsa-sha2-nistp384");
+	add_hostkey_pref_if_avail(known_hosts, hostname, port, prefs, LIBSSH2_KNOWNHOST_KEY_ECDSA_521, "ecdsa-sha2-nistp521");
+#endif
+	add_hostkey_pref_if_avail(known_hosts, hostname, port, prefs, LIBSSH2_KNOWNHOST_KEY_SSHRSA, "ssh-rsa");
 }
 
 static int _git_ssh_session_create(
@@ -526,11 +524,11 @@ static int _git_ssh_session_create(
 	int port,
 	git_stream *io)
 {
-	int rc = 0;
+	git_socket_stream *socket = GIT_CONTAINER_OF(io, git_socket_stream, parent);
 	LIBSSH2_SESSION *s;
 	LIBSSH2_KNOWNHOSTS *known_hosts;
-	git_socket_stream *socket = GIT_CONTAINER_OF(io, git_socket_stream, parent);
-	const char *keytype = NULL;
+	git_str prefs = GIT_STR_INIT;
+	int rc = 0;
 
 	GIT_ASSERT_ARG(session);
 	GIT_ASSERT_ARG(hosts);
@@ -547,16 +545,17 @@ static int _git_ssh_session_create(
 		return -1;
 	}
 
-	if ((keytype = find_hostkey_preference(known_hosts, hostname, port)) != NULL) {
+	find_hostkey_preference(known_hosts, hostname, port, &prefs);
+	if (git_str_len(&prefs) > 0) {
 		do {
-			rc = libssh2_session_method_pref(s, LIBSSH2_METHOD_HOSTKEY, keytype);
+			rc = libssh2_session_method_pref(s, LIBSSH2_METHOD_HOSTKEY, git_str_cstr(&prefs));
 		} while (LIBSSH2_ERROR_EAGAIN == rc || LIBSSH2_ERROR_TIMEOUT == rc);
 		if (rc != LIBSSH2_ERROR_NONE) {
 			ssh_error(s, "failed to set hostkey preference");
 			goto on_error;
 		}
 	}
-
+	git_str_dispose(&prefs);
 
 	do {
 		rc = libssh2_session_handshake(s, socket->s);
@@ -753,7 +752,7 @@ static int check_certificate(
 		if (error == GIT_PASSTHROUGH) {
 			error = git_error_state_restore(&previous_error);
 		} else if (error < 0 && !git_error_last()) {
-			git_error_set(GIT_ERROR_NET, "user canceled hostkey check");
+			git_error_set(GIT_ERROR_NET, "unknown remote host key");
 		}
 
 		git_error_state_free(&previous_error);
@@ -1009,7 +1008,7 @@ static int list_auth_methods(int *out, LIBSSH2_SESSION *session, const char *use
 
 	/* either error, or the remote accepts NONE auth, which is bizarre, let's punt */
 	if (list == NULL && !libssh2_userauth_authenticated(session)) {
-		ssh_error(session, "Failed to retrieve list of SSH authentication methods");
+		ssh_error(session, "remote rejected authentication");
 		return GIT_EAUTH;
 	}
 
diff --git a/src/util/futils.c b/src/util/futils.c
index cb872de09..084f1cd28 100644
--- a/src/util/futils.c
+++ b/src/util/futils.c
@@ -13,9 +13,6 @@
 #include "rand.h"
 
 #include <ctype.h>
-#if GIT_WIN32
-#include "win32/findfile.h"
-#endif
 
 #define GIT_FILEMODE_DEFAULT 0100666
 
diff --git a/src/util/win32/findfile.c b/src/util/win32/findfile.c
deleted file mode 100644
index 725a90167..000000000
--- a/src/util/win32/findfile.c
+++ /dev/null
@@ -1,286 +0,0 @@
-/*
- * Copyright (C) the libgit2 contributors. All rights reserved.
- *
- * This file is part of libgit2, distributed under the GNU GPL v2 with
- * a Linking Exception. For full terms see the included COPYING file.
- */
-
-#include "findfile.h"
-
-#include "path_w32.h"
-#include "utf-conv.h"
-#include "fs_path.h"
-
-#define REG_GITFORWINDOWS_KEY       L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"
-#define REG_GITFORWINDOWS_KEY_WOW64 L"SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"
-
-static int git_win32__expand_path(git_win32_path dest, const wchar_t *src)
-{
-	DWORD len = ExpandEnvironmentStringsW(src, dest, GIT_WIN_PATH_UTF16);
-
-	if (!len || len > GIT_WIN_PATH_UTF16)
-		return -1;
-
-	return 0;
-}
-
-static int win32_path_to_8(git_str *dest, const wchar_t *src)
-{
-	git_win32_utf8_path utf8_path;
-
-	if (git_win32_path_to_utf8(utf8_path, src) < 0) {
-		git_error_set(GIT_ERROR_OS, "unable to convert path to UTF-8");
-		return -1;
-	}
-
-	/* Convert backslashes to forward slashes */
-	git_fs_path_mkposix(utf8_path);
-
-	return git_str_sets(dest, utf8_path);
-}
-
-static git_win32_path mock_registry;
-static bool mock_registry_set;
-
-extern int git_win32__set_registry_system_dir(const wchar_t *mock_sysdir)
-{
-	if (!mock_sysdir) {
-		mock_registry[0] = L'\0';
-		mock_registry_set = false;
-	} else {
-		size_t len = wcslen(mock_sysdir);
-
-		if (len > GIT_WIN_PATH_MAX) {
-			git_error_set(GIT_ERROR_INVALID, "mock path too long");
-			return -1;
-		}
-
-		wcscpy(mock_registry, mock_sysdir);
-		mock_registry_set = true;
-	}
-
-	return 0;
-}
-
-static int lookup_registry_key(
-	git_win32_path out,
-	const HKEY hive,
-	const wchar_t* key,
-	const wchar_t *value)
-{
-	HKEY hkey;
-	DWORD type, size;
-	int error = GIT_ENOTFOUND;
-
-	/*
-	 * Registry data may not be NUL terminated, provide room to do
-	 * it ourselves.
-	 */
-	size = (DWORD)((sizeof(git_win32_path) - 1) * sizeof(wchar_t));
-
-	if (RegOpenKeyExW(hive, key, 0, KEY_READ, &hkey) != 0)
-		return GIT_ENOTFOUND;
-
-	if (RegQueryValueExW(hkey, value, NULL, &type, (LPBYTE)out, &size) == 0 &&
-	    type == REG_SZ &&
-	    size > 0 &&
-	    size < sizeof(git_win32_path)) {
-		size_t wsize = size / sizeof(wchar_t);
-		size_t len = wsize - 1;
-
-		if (out[wsize - 1] != L'\0') {
-			len = wsize;
-			out[wsize] = L'\0';
-		}
-
-		if (out[len - 1] == L'\\')
-			out[len - 1] = L'\0';
-
-		if (_waccess(out, F_OK) == 0)
-			error = 0;
-	}
-
-	RegCloseKey(hkey);
-	return error;
-}
-
-static int find_sysdir_in_registry(git_win32_path out)
-{
-	if (mock_registry_set) {
-		if (mock_registry[0] == L'\0')
-			return GIT_ENOTFOUND;
-
-		wcscpy(out, mock_registry);
-		return 0;
-	}
-
-	if (lookup_registry_key(out, HKEY_CURRENT_USER, REG_GITFORWINDOWS_KEY, L"InstallLocation") == 0 ||
-	    lookup_registry_key(out, HKEY_CURRENT_USER, REG_GITFORWINDOWS_KEY_WOW64, L"InstallLocation") == 0 ||
-	    lookup_registry_key(out, HKEY_LOCAL_MACHINE, REG_GITFORWINDOWS_KEY, L"InstallLocation") == 0 ||
-	    lookup_registry_key(out, HKEY_LOCAL_MACHINE, REG_GITFORWINDOWS_KEY_WOW64, L"InstallLocation") == 0)
-		return 0;
-
-    return GIT_ENOTFOUND;
-}
-
-static int find_sysdir_in_path(git_win32_path out)
-{
-	size_t out_len;
-
-	if (git_win32_path_find_executable(out, L"git.exe") < 0 &&
-	    git_win32_path_find_executable(out, L"git.cmd") < 0)
-		return GIT_ENOTFOUND;
-
-	out_len = wcslen(out);
-
-	/* Trim the file name */
-	if (out_len <= CONST_STRLEN(L"git.exe"))
-		return GIT_ENOTFOUND;
-
-	out_len -= CONST_STRLEN(L"git.exe");
-
-	if (out_len && out[out_len - 1] == L'\\')
-		out_len--;
-
-	/*
-	 * Git for Windows usually places the command in a 'bin' or
-	 * 'cmd' directory, trim that.
-	 */
-	if (out_len >= CONST_STRLEN(L"\\bin") &&
-	    wcsncmp(&out[out_len - CONST_STRLEN(L"\\bin")], L"\\bin", CONST_STRLEN(L"\\bin")) == 0)
-		out_len -= CONST_STRLEN(L"\\bin");
-	else if (out_len >= CONST_STRLEN(L"\\cmd") &&
-	         wcsncmp(&out[out_len - CONST_STRLEN(L"\\cmd")], L"\\cmd", CONST_STRLEN(L"\\cmd")) == 0)
-		out_len -= CONST_STRLEN(L"\\cmd");
-
-	if (!out_len)
-		return GIT_ENOTFOUND;
-
-	out[out_len] = L'\0';
-	return 0;
-}
-
-static int win32_find_existing_dirs(
-    git_str* out,
-    const wchar_t* tmpl[])
-{
-	git_win32_path path16;
-	git_str buf = GIT_STR_INIT;
-
-	git_str_clear(out);
-
-	for (; *tmpl != NULL; tmpl++) {
-		if (!git_win32__expand_path(path16, *tmpl) &&
-		    path16[0] != L'%' &&
-		    !_waccess(path16, F_OK)) {
-			win32_path_to_8(&buf, path16);
-
-			if (buf.size)
-				git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);
-		}
-	}
-
-	git_str_dispose(&buf);
-
-	return (git_str_oom(out) ? -1 : 0);
-}
-
-static int append_subdir(git_str *out, git_str *path, const char *subdir)
-{
-	static const char* architecture_roots[] = {
-		"",
-		"mingw64",
-		"mingw32",
-		NULL
-	};
-	const char **root;
-	size_t orig_path_len = path->size;
-
-	for (root = architecture_roots; *root; root++) {
-		if ((*root[0] && git_str_joinpath(path, path->ptr, *root) < 0) ||
-		    git_str_joinpath(path, path->ptr, subdir) < 0)
-			return -1;
-
-		if (git_fs_path_exists(path->ptr) &&
-		    git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, path->ptr) < 0)
-			return -1;
-
-		git_str_truncate(path, orig_path_len);
-	}
-
-	return 0;
-}
-
-int git_win32__find_system_dirs(git_str *out, const char *subdir)
-{
-	git_win32_path pathdir, regdir;
-	git_str path8 = GIT_STR_INIT;
-	bool has_pathdir, has_regdir;
-	int error;
-
-	has_pathdir = (find_sysdir_in_path(pathdir) == 0);
-	has_regdir = (find_sysdir_in_registry(regdir) == 0);
-
-	if (!has_pathdir && !has_regdir)
-		return 0;
-
-	/*
-	 * Usually the git in the path is the same git in the registry,
-	 * in this case there's no need to duplicate the paths.
-	 */
-	if (has_pathdir && has_regdir && wcscmp(pathdir, regdir) == 0)
-		has_regdir = false;
-
-	if (has_pathdir) {
-		if ((error = win32_path_to_8(&path8, pathdir)) < 0 ||
-		    (error = append_subdir(out, &path8, subdir)) < 0)
-			goto done;
-	}
-
-	if (has_regdir) {
-		if ((error = win32_path_to_8(&path8, regdir)) < 0 ||
-		    (error = append_subdir(out, &path8, subdir)) < 0)
-			goto done;
-	}
-
-done:
-    git_str_dispose(&path8);
-    return error;
-}
-
-int git_win32__find_global_dirs(git_str *out)
-{
-	static const wchar_t *global_tmpls[4] = {
-		L"%HOME%\\",
-		L"%HOMEDRIVE%%HOMEPATH%\\",
-		L"%USERPROFILE%\\",
-		NULL,
-	};
-
-	return win32_find_existing_dirs(out, global_tmpls);
-}
-
-int git_win32__find_xdg_dirs(git_str *out)
-{
-	static const wchar_t *global_tmpls[7] = {
-		L"%XDG_CONFIG_HOME%\\git",
-		L"%APPDATA%\\git",
-		L"%LOCALAPPDATA%\\git",
-		L"%HOME%\\.config\\git",
-		L"%HOMEDRIVE%%HOMEPATH%\\.config\\git",
-		L"%USERPROFILE%\\.config\\git",
-		NULL,
-	};
-
-	return win32_find_existing_dirs(out, global_tmpls);
-}
-
-int git_win32__find_programdata_dirs(git_str *out)
-{
-	static const wchar_t *programdata_tmpls[2] = {
-		L"%PROGRAMDATA%\\Git",
-		NULL,
-	};
-
-	return win32_find_existing_dirs(out, programdata_tmpls);
-}
diff --git a/src/util/win32/findfile.h b/src/util/win32/findfile.h
deleted file mode 100644
index 7b191d1fe..000000000
--- a/src/util/win32/findfile.h
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Copyright (C) the libgit2 contributors. All rights reserved.
- *
- * This file is part of libgit2, distributed under the GNU GPL v2 with
- * a Linking Exception. For full terms see the included COPYING file.
- */
-
-#ifndef INCLUDE_win32_findfile_h__
-#define INCLUDE_win32_findfile_h__
-
-#include "git2_util.h"
-
-/** Sets the mock registry root for Git for Windows for testing. */
-extern int git_win32__set_registry_system_dir(const wchar_t *mock_sysdir);
-
-extern int git_win32__find_system_dirs(git_str *out, const char *subpath);
-extern int git_win32__find_global_dirs(git_str *out);
-extern int git_win32__find_xdg_dirs(git_str *out);
-extern int git_win32__find_programdata_dirs(git_str *out);
-
-#endif
-