src/filesystem/unix/SDL_sysfilesystem.c
author Ryan C. Gordon <icculus@icculus.org>
Tue, 20 Aug 2013 19:57:11 -0400
changeset 7667 be1cc6f55840
child 7668 66da4242ce53
permissions -rw-r--r--
Added SDL_GetBasePath() and SDL_GetPrefPath() in new filesystem module.
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/*
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  Simple DirectMedia Layer
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  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
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  This software is provided 'as-is', without any express or implied
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  warranty.  In no event will the authors be held liable for any damages
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  arising from the use of this software.
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  Permission is granted to anyone to use this software for any purpose,
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  including commercial applications, and to alter it and redistribute it
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  freely, subject to the following restrictions:
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  1. The origin of this software must not be misrepresented; you must not
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     claim that you wrote the original software. If you use this software
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     in a product, an acknowledgment in the product documentation would be
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     appreciated but is not required.
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  2. Altered source versions must be plainly marked as such, and must not be
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     misrepresented as being the original software.
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  3. This notice may not be removed or altered from any source distribution.
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*/
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#include "SDL_config.h"
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#ifdef SDL_FILESYSTEM_UNIX
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/* System dependent filesystem routines                                */
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#include <unistd.h>
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#include "SDL_error.h"
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#include "SDL_stdinc.h"
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#include "SDL_filesystem.h"
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static char *readSymLink(const char *path)
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{
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    char *retval = NULL;
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    ssize_t len = 64;
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    ssize_t rc = -1;
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    while (1)
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    {
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        char *ptr = (char *) SDL_realloc(retval, (size_t) len);
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        if (ptr == NULL) {
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            SDL_OutOfMemory();
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            break;
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        }
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        retval = ptr;
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        rc = readlink(path, retval, len);
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        if (rc == -1) {
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            break;  /* not a symlink, i/o error, etc. */
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        } else if (rc < len) {
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            retval[rc] = '\0';  /* readlink doesn't null-terminate. */
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            return retval;  /* we're good to go. */
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        }
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        len *= 2;  /* grow buffer, try again. */
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    }
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    if (retval != NULL) {
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        SDL_free(retval);
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    }
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    return NULL;
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}
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char *
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SDL_GetBasePath(void)
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{
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    char *retval = NULL;
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    /* is a Linux-style /proc filesystem available? */
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    if (access("/proc", F_OK) {
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        retval = readSymLink("/proc/self/exe");
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        if (retval == NULL) {
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            /* older kernels don't have /proc/self ... try PID version... */
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            char path[64];
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            const int rc = (int) SDL_snprintf(path, sizeof(path),
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                                              "/proc/%llu/exe",
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                                              (unsigned long long) getpid());
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            if ( (rc > 0) && (rc < sizeof(path)) ) {
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                retval = readSymLink(path);
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            }
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        }
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    }
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    /* If we had access to argv[0] here, we could check it for a path,
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        or troll through $PATH looking for it, too. */
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    if (retval != NULL) { /* chop off filename. */
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        char *ptr = SDL_strrchr(retval, '/');
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        if (ptr != NULL) {
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            *(ptr+1) = '\0';
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        } else {  /* shouldn't happen, but just in case... */
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            SDL_free(retval);
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            retval = NULL;
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        }
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    }
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    if (retval != NULL) {
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        /* try to shrink buffer... */
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        char *ptr = (char *) SDL_realloc(retval, strlen(retval) + 1);
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        if (ptr != NULL)
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            retval = ptr;  /* oh well if it failed. */
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    }
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    return retval;
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}
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char *
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SDL_GetPrefPath(const char *org, const char *app)
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{
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    /*
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     * We use XDG's base directory spec, even if you're not on Linux.
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     *  This isn't strictly correct, but the results are relatively sane
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     *  in any case.
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     *
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     * http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
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     */
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    const char *envr = SDL_getenv("XDG_DATA_HOME");
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    const char *append = "/";
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    char *retval = NULL;
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    char *ptr = NULL;
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    size_t len = 0;
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    if (!envr) {
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        /* You end up with "$HOME/.local/share/Game Name 2" */
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        envr = SDL_getenv("HOME");
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        if (!envr) {
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            /* we could take heroic measures with /etc/passwd, but oh well. */
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            SDL_SetError("neither XDG_DATA_HOME nor HOME environment is set");
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            return NULL;
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        }
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        append = ".local/share/";
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    } /* if */
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    len = SDL_strlen(envr) + SDL_strlen(append) + SDL_strlen(app) + 2;
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    retval = (char *) SDL_malloc(len);
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    if (!retval) {
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        SDL_OutOfMemory();
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        return NULL;
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    }
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    SDL_snprintf(retval, len, "%s%s%s/", envr, append, app);
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    for (ptr = retval+1; *ptr; ptr++) {
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        if (*ptr == '/') {
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            *ptr = '\0';
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            mkdir(retval, 0700);
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            *ptr = '/';
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        }
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    }
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    mkdir(retval, 0700);
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    return retval;
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}
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#endif /* SDL_FILESYSTEM_UNIX */
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