[PATCH 2/2] Load modules from $libdir/pkcs11

[Kalev Lember]

So far we have only supported full paths to the pkcs11 modules in config
files. This change adds relative path support, so that for modules
installed under the standard $libdir/pkcs11, the config file won't have
to spell out the full path.
---
 configure.ac            |    9 +++++++
 p11-kit/modules.c       |   59 ++++++++++++++++++++++++++++++++++++++++++++--
 p11-kit/p11-kit-1.pc.in |    1 +
 3 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index 9111cf1..71b9f58 100644
--- a/configure.ac
+++ b/configure.ac
@@ -59,21 +59,29 @@ AC_ARG_WITH([pkcs11-config-dir],
             [pkcs11_config_dir=$withval],
             [pkcs11_config_dir=$sysconfdir/pkcs11])
 
+AC_ARG_WITH([pkcs11-modules-dir],
+            [AS_HELP_STRING([--with-pkcs11-modules-dir], [Change PKCS#11 system modules directory])],
+            [pkcs11_modules_dir=$withval],
+            [pkcs11_modules_dir=$libdir/pkcs11])
+
 # We expand these so we have concrete paths
 p11_system_dir=$(eval echo $pkcs11_config_dir)
 p11_system_conf=$(eval echo $p11_system_dir/pkcs11.conf)
 p11_system_modules_config_dir=$(eval echo $p11_system_dir/modules)
+p11_system_modules_dir=$(eval echo $pkcs11_modules_dir)
 p11_user_conf="~/.pkcs11/pkcs11.conf"
 p11_user_modules_config_dir="~/.pkcs11/modules"
 
 AC_DEFINE_UNQUOTED(P11_SYSTEM_CONF, "$p11_system_conf", [System configuration file])
 AC_DEFINE_UNQUOTED(P11_SYSTEM_MODULES_CONFIG_DIR, "$p11_system_modules_config_dir", [System modules configuration dir])
+AC_DEFINE_UNQUOTED(P11_SYSTEM_MODULES_DIR, "$p11_system_modules_dir", [System modules dir])
 AC_DEFINE_UNQUOTED(P11_USER_CONF, "$p11_user_conf", [User configuration file])
 AC_DEFINE_UNQUOTED(P11_USER_MODULES_CONFIG_DIR, "$p11_user_modules_config_dir", [User modules configuration dir])
 
 AC_SUBST(p11_system_dir)
 AC_SUBST(p11_system_conf)
 AC_SUBST(p11_system_modules_config_dir)
+AC_SUBST(p11_system_modules_dir)
 AC_SUBST(p11_user_conf)
 AC_SUBST(p11_user_modules_config_dir)
 
@@ -192,4 +200,5 @@ AC_MSG_NOTICE([build options:
     User Global Config:              $p11_user_conf
     System Module Config Directory:  $p11_system_modules_config_dir
     User Module Config Directory:    $p11_user_modules_config_dir
+    System Module Directory:         $p11_system_modules_dir
 ])
diff --git a/p11-kit/modules.c b/p11-kit/modules.c
index 4cfb4cb..5ff5e6f 100644
--- a/p11-kit/modules.c
+++ b/p11-kit/modules.c
@@ -244,6 +244,35 @@ alloc_module_unlocked (void)
 	return mod;
 }
 
+static int
+is_relative_path (const char *path)
+{
+	assert (path);
+
+	return (*path != '/');
+}
+
+static char*
+build_path (const char *dir, const char *filename)
+{
+	char *path;
+	int len;
+
+	assert (dir);
+	assert (filename);
+
+	len = snprintf (NULL, 0, "%s/%s", dir, filename) + 1;
+	if (len <= 0 || len > PATH_MAX)
+		return NULL;
+
+	if (!(path = malloc (len)))
+		return NULL;
+
+	sprintf (path, "%s/%s", dir, filename);
+
+	return path;
+}
+
 static CK_RV
 dlopen_and_get_function_list (Module *mod, const char *path)
 {
@@ -312,11 +341,25 @@ load_module_from_file_unlocked (const char *path, Module **result)
 	return CKR_OK;
 }
 
+static char*
+expand_module_path (const char *filename)
+{
+	char *path;
+
+	if (is_relative_path (filename))
+		path = build_path (P11_SYSTEM_MODULES_DIR, filename);
+	else
+		path = strdup (filename);
+
+	return path;
+}
+
 static CK_RV
 take_config_and_load_module_unlocked (char **name, hashmap **config)
 {
 	Module *mod, *prev;
-	const char *path;
+	const char *module_filename;
+	char *path;
 	CK_RV rv;
 
 	assert (name);
@@ -324,12 +367,22 @@ take_config_and_load_module_unlocked (char **name, hashmap **config)
 	assert (config);
 	assert (*config);
 
-	path = hash_get (*config, "module");
-	if (path == NULL) {
+	module_filename = hash_get (*config, "module");
+	if (module_filename == NULL) {
 		debug ("no module path for module, skipping: %s", *name);
 		return CKR_OK;
 	}
 
+	path = expand_module_path (module_filename);
+	if (!path)
+		return CKR_HOST_MEMORY;
+
+	/* The hash map will take ownership of the variable */
+	if (!hash_set (*config, "module", path)) {
+		free (path);
+		return CKR_HOST_MEMORY;
+	}
+
 	mod = alloc_module_unlocked ();
 	if (!mod)
 		return CKR_HOST_MEMORY;
diff --git a/p11-kit/p11-kit-1.pc.in b/p11-kit/p11-kit-1.pc.in
index dac411a..8eda9c0 100644
--- a/p11-kit/p11-kit-1.pc.in
+++ b/p11-kit/p11-kit-1.pc.in
@@ -7,6 +7,7 @@ datadir=@datadir@
 sysconfdir=@sysconfdir@
 p11_system_conf=@p11_system_conf@
 p11_system_modules_config_dir=@p11_system_modules_config_dir@
+p11_system_modules_dir=@p11_system_modules_dir@
 p11_user_conf=@p11_user_conf@
 p11_user_modules_config_dir=@p11_user_modules_config_dir@
 proxy_module=@libdir@/p11-kit-proxy.so
-- 
1.7.6.2