source: ps/trunk/source/lib/sysdep/os/unix/unix_executable_pathname.cpp

/* Copyright (C) 2014 Wildfire Games.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include "precompiled.h"

#include "lib/sysdep/sysdep.h"

#define GNU_SOURCE
#include "mocks/dlfcn.h"
#include "mocks/unistd.h"

#include <cstdio>

OsPath unix_ExecutablePathname()
{
    // Find the executable's filename
    Dl_info dl_info;
    memset(&dl_info, 0, sizeof(dl_info));
    if (!T::dladdr((void *)sys_ExecutablePathname, &dl_info) || !dl_info.dli_fname)
        return OsPath();
    const char* path = dl_info.dli_fname;

    // If this looks like an absolute path, use realpath to get the normalized
    // path (with no '.' or '..')
    if (path[0] == '/')
    {
        char resolved[PATH_MAX];
        if (!realpath(path, resolved))
            return OsPath();
        return resolved;
    }

    // If this looks like a relative path, resolve against cwd and use realpath
    if (strchr(path, '/'))
    {
        char cwd[PATH_MAX];
        if (!T::getcwd(cwd, PATH_MAX))
            return OsPath();

        char absolute[PATH_MAX];
        int ret = snprintf(absolute, PATH_MAX, "%s/%s", cwd, path);
        if (ret < 0 || ret >= PATH_MAX)
            return OsPath(); // path too long, or other error
        char resolved[PATH_MAX];
        if (!realpath(absolute, resolved))
            return OsPath();
        return resolved;
    }

    // If it's not a path at all, i.e. it's just a filename, we'd
    // probably have to search through PATH to find it.
    // That's complex and should be uncommon, so don't bother.
    return OsPath();
}