Add exe querying routines

Makefile.am

@@ -26,6 +26,8 @@ UTIL_FILES   =		\
     endian.hpp		\
     except.cpp  	\
     except.hpp  	\
+    exe.cpp		\
+    exe.hpp		\
     extent.cpp		\
     extent.hpp		\
     fixed.cpp		\

exe.cpp

@@ -0,0 +1,62 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim 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 General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2010-2012 Danny Robson <danny@nerdcruft.net>
+ */
+
+
+#include "exe.hpp"
+
+#include "platform.hpp"
+
+#ifdef PLATFORM_LINUX
+
+#include "types.hpp"
+#include "except.hpp"
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <unistd.h>
+#include <stdexcept>
+#include <vector>
+
+boost::filesystem::path
+util::image_path (void) {
+        static const char PROC_SELF[] = "/proc/self/exe";
+
+        // We can't use lstat to check the size of the link in proc, as Linux
+        // will return 0 for most entries under proc. Instead we've got to
+        // iterate for a correct size.
+        
+        std::vector<char> resolved (256);
+
+retry:
+        const auto written = readlink (PROC_SELF, resolved.data (), resolved.size ());
+        if (written < 0)
+            errno_error::throw_code ();
+
+        if (sign_cast<size_t> (written) == resolved.size ()) {
+            resolved.resize (resolved.size () * 2);
+            goto retry;
+        }
+
+        return boost::filesystem::path (resolved.data (), resolved.data () + written);
+}
+
+#else
+    #error "Unknown platform"
+#endif

exe.hpp

@@ -0,0 +1,29 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim 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 General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2010-2012 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef __UTIL_EXE_HPP
+#define __UTIL_EXE_HPP
+
+#include <boost/filesystem/path.hpp>
+
+namespace util {
+    boost::filesystem::path image_path (void);
+}
+
+#endif