Add libgcrypt, check for it and perform global initialization

INSTALL

@@ -31,6 +31,7 @@ General libraries:
  - libevent 1.4+
  - libavl
  - MiniXML
+ - gcrypt 1.2.0+
  - libflac (optional - FLAC support)
  - taglib (optional - Musepack support)
  - libplist 0.16+ (optional - iTunes XML support)

configure.in

@@ -86,6 +86,8 @@ AC_CHECK_HEADER(antlr3.h, , AC_MSG_ERROR([antlr3.h not found]))
 AC_CHECK_LIB([antlr3c], [antlr3BaseRecognizerNew], [ANTLR3C_LIBS="-lantlr3c"], AC_MSG_ERROR([ANTLR3 C runtime (libantlr3c) not found]))
 AC_SUBST(ANTLR3C_LIBS)
 
+AM_PATH_LIBGCRYPT([], , AC_MSG_ERROR([libgcrypt not found]))
+
 if test x$use_flac = xtrue; then
 	PKG_CHECK_MODULES(FLAC, [ flac ])
 fi

src/Makefile.am

@@ -25,10 +25,10 @@ ANTLR_SOURCES = \
 
 ANTLR_PRODUCTS =
 
-forked_daapd_CPPFLAGS = -D_GNU_SOURCE @AVAHI_CFLAGS@ @SQLITE3_CFLAGS@ @FFMPEG_CFLAGS@ @CONFUSE_CFLAGS@ @TAGLIB_CFLAGS@ @MINIXML_CFLAGS@ @LIBPLIST_CFLAGS@ \
+forked_daapd_CPPFLAGS = -D_GNU_SOURCE @AVAHI_CFLAGS@ @SQLITE3_CFLAGS@ @FFMPEG_CFLAGS@ @CONFUSE_CFLAGS@ @TAGLIB_CFLAGS@ @MINIXML_CFLAGS@ @LIBPLIST_CFLAGS@ @LIBGCRYPT_CFLAGS@ \
 	-DDATADIR="\"$(pkgdatadir)\"" -DCONFDIR="\"$(sysconfdir)\"" -DSTATEDIR="\"$(localstatedir)\""
 
-forked_daapd_LDADD = @AVAHI_LIBS@ @SQLITE3_LIBS@ @FFMPEG_LIBS@ @CONFUSE_LIBS@ @FLAC_LIBS@ @TAGLIB_LIBS@ @LIBEVENT_LIBS@ @LIBAVL_LIBS@ @MINIXML_LIBS@ @ANTLR3C_LIBS@ @LIBPLIST_LIBS@
+forked_daapd_LDADD = @AVAHI_LIBS@ @SQLITE3_LIBS@ @FFMPEG_LIBS@ @CONFUSE_LIBS@ @FLAC_LIBS@ @TAGLIB_LIBS@ @LIBEVENT_LIBS@ @LIBAVL_LIBS@ @MINIXML_LIBS@ @ANTLR3C_LIBS@ @LIBPLIST_LIBS@ @LIBGCRYPT_LIBS@
 forked_daapd_SOURCES = main.c \
 	db.c db.h \
 	logger.c logger.h \

src/main.c

@@ -51,6 +51,9 @@
 #include <event.h>
 #include <libavformat/avformat.h>
 
+#include <gcrypt.h>
+GCRY_THREAD_OPTION_PTHREAD_IMPL;
+
 #include "conffile.h"
 #include "db.h"
 #include "logger.h"
@@ -425,6 +428,7 @@ main(int argc, char **argv)
   char *logfile;
   char *ffid;
   char *pidfile;
+  const char *gcry_version;
   sigset_t sigs;
   int sigfd;
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
@@ -552,6 +556,26 @@ main(int argc, char **argv)
   /* Initialize ffmpeg */
   av_register_all();
 
+  /* Initialize libgcrypt */
+  gcry_control(GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);
+
+  gcry_version = gcry_check_version(GCRYPT_VERSION);
+  if (!gcry_version)
+    {
+      DPRINTF(E_FATAL, L_MAIN, "libgcrypt version mismatch\n");
+
+      goto gcrypt_init_fail;
+    }
+
+  /* We aren't handling anything sensitive, so give up on secure
+   * memory, which is a scarce system resource.
+   */
+  gcry_control(GCRYCTL_DISABLE_SECMEM, 0);
+
+  gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
+
+  DPRINTF(E_DBG, L_MAIN, "Initialized with gcrypt %s\n", gcry_version);
+
   /* Block signals for all threads except the main one */
   sigemptyset(&sigs);
   sigaddset(&sigs, SIGINT);
@@ -743,6 +767,7 @@ main(int argc, char **argv)
 	}
     }
 
+ gcrypt_init_fail:
  signal_block_fail:
   DPRINTF(E_LOG, L_MAIN, "Exiting.\n");
   conffile_unload();