Move gcrypt-util to basic/

We were including gcrypt-util.[ch] by hand in the few places where it
was used. Create a convenience library to avoid compiling the same
files multiple times.

v2:
- use a separate static library instead of mergin into libbasic

src/basic/gcrypt-util.c

@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2012 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#if HAVE_GCRYPT
+#include <gcrypt.h>
+
+#include "gcrypt-util.h"
+#include "hexdecoct.h"
+
+void initialize_libgcrypt(bool secmem) {
+        const char *p;
+        if (gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P))
+                return;
+
+        p = gcry_check_version("1.4.5");
+        assert(p);
+
+        /* Turn off "secmem". Clients which wish to make use of this
+         * feature should initialize the library manually */
+        if (!secmem)
+                gcry_control(GCRYCTL_DISABLE_SECMEM);
+        gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
+}
+
+int string_hashsum(const char *s, size_t len, int md_algorithm, char **out) {
+        gcry_md_hd_t md = NULL;
+        size_t hash_size;
+        void *hash;
+        char *enc;
+
+        initialize_libgcrypt(false);
+
+        hash_size = gcry_md_get_algo_dlen(md_algorithm);
+        assert(hash_size > 0);
+
+        gcry_md_open(&md, md_algorithm, 0);
+        if (!md)
+                return -EIO;
+
+        gcry_md_write(md, s, len);
+
+        hash = gcry_md_read(md, 0);
+        if (!hash)
+                return -EIO;
+
+        enc = hexmem(hash, hash_size);
+        if (!enc)
+                return -ENOMEM;
+
+        *out = enc;
+        return 0;
+}
+#endif

src/basic/gcrypt-util.h

@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2016 Zbigniew Jędrzejewski-Szmek
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+#if HAVE_GCRYPT
+#include <gcrypt.h>
+
+void initialize_libgcrypt(bool secmem);
+int string_hashsum(const char *s, size_t len, int md_algorithm, char **out);
+#endif
+
+static inline int string_hashsum_sha224(const char *s, size_t len, char **out) {
+#if HAVE_GCRYPT
+        return string_hashsum(s, len, GCRY_MD_SHA224, out);
+#else
+        return -EOPNOTSUPP;
+#endif
+}
+
+static inline int string_hashsum_sha256(const char *s, size_t len, char **out) {
+#if HAVE_GCRYPT
+        return string_hashsum(s, len, GCRY_MD_SHA256, out);
+#else
+        return -EOPNOTSUPP;
+#endif
+}

src/basic/meson.build

@@ -306,3 +306,13 @@ libbasic = static_library(
                         libselinux],
         c_args : ['-fvisibility=default'],
         install : false)
+
+# A convenience library that is separate from libbasic to avoid
+# unnecessary linking to libgcrypt.
+libbasic_gcrypt = static_library(
+        'basic-gcrypt',
+        'gcrypt-util.c',
+        'gcrypt-util.h',
+        include_directories : includes,
+        dependencies : [libgcrypt],
+        c_args : ['-fvisibility=default'])