src/filesystem/unix/SDL_sysfilesystem.c
author Sam Lantinga <slouken@libsdl.org>
Sat, 02 Jan 2016 10:10:34 -0800
changeset 9998 f67cf37e9cd4
parent 9619 b94b6d0bff0f
child 10061 698a7d8626b9
permissions -rw-r--r--
Updated copyright to 2016
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 #include "../../SDL_internal.h"
    22 
    23 #ifdef SDL_FILESYSTEM_UNIX
    24 
    25 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
    26 /* System dependent filesystem routines                                */
    27 
    28 #include <errno.h>
    29 #include <stdio.h>
    30 #include <unistd.h>
    31 #include <stdlib.h>
    32 #include <sys/stat.h>
    33 #include <sys/types.h>
    34 #include <limits.h>
    35 
    36 #ifdef __FREEBSD__
    37 #include <sys/sysctl.h>
    38 #endif
    39 
    40 #include "SDL_error.h"
    41 #include "SDL_stdinc.h"
    42 #include "SDL_filesystem.h"
    43 
    44 static char *
    45 readSymLink(const char *path)
    46 {
    47     char *retval = NULL;
    48     ssize_t len = 64;
    49     ssize_t rc = -1;
    50 
    51     while (1)
    52     {
    53         char *ptr = (char *) SDL_realloc(retval, (size_t) len);
    54         if (ptr == NULL) {
    55             SDL_OutOfMemory();
    56             break;
    57         }
    58 
    59         retval = ptr;
    60 
    61         rc = readlink(path, retval, len);
    62         if (rc == -1) {
    63             break;  /* not a symlink, i/o error, etc. */
    64         } else if (rc < len) {
    65             retval[rc] = '\0';  /* readlink doesn't null-terminate. */
    66             return retval;  /* we're good to go. */
    67         }
    68 
    69         len *= 2;  /* grow buffer, try again. */
    70     }
    71 
    72     SDL_free(retval);
    73     return NULL;
    74 }
    75 
    76 
    77 char *
    78 SDL_GetBasePath(void)
    79 {
    80     char *retval = NULL;
    81 
    82 #if defined(__FREEBSD__)
    83     char fullpath[PATH_MAX];
    84     size_t buflen = sizeof (fullpath);
    85     const int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1 };
    86     if (sysctl(mib, SDL_arraysize(mib), fullpath, &buflen, NULL, 0) != -1) {
    87         retval = SDL_strdup(fullpath);
    88         if (!retval) {
    89             SDL_OutOfMemory();
    90             return NULL;
    91         }
    92     }
    93 #elif defined(__SOLARIS__)
    94     const char *path = getexecname();
    95     if ((path != NULL) && (path[0] == '/')) { /* must be absolute path... */
    96         retval = SDL_strdup(path);
    97         if (!retval) {
    98             SDL_OutOfMemory();
    99             return NULL;
   100         }
   101     }
   102 #endif
   103 
   104     /* is a Linux-style /proc filesystem available? */
   105     if (!retval && (access("/proc", F_OK) == 0)) {
   106 #if defined(__FREEBSD__)
   107         retval = readSymLink("/proc/curproc/file");
   108 #elif defined(__NETBSD__)
   109         retval = readSymLink("/proc/curproc/exe");
   110 #else
   111         retval = readSymLink("/proc/self/exe");  /* linux. */
   112 #endif
   113         if (retval == NULL) {
   114             /* older kernels don't have /proc/self ... try PID version... */
   115             char path[64];
   116             const int rc = (int) SDL_snprintf(path, sizeof(path),
   117                                               "/proc/%llu/exe",
   118                                               (unsigned long long) getpid());
   119             if ( (rc > 0) && (rc < sizeof(path)) ) {
   120                 retval = readSymLink(path);
   121             }
   122         }
   123     }
   124 
   125     /* If we had access to argv[0] here, we could check it for a path,
   126         or troll through $PATH looking for it, too. */
   127 
   128     if (retval != NULL) { /* chop off filename. */
   129         char *ptr = SDL_strrchr(retval, '/');
   130         if (ptr != NULL) {
   131             *(ptr+1) = '\0';
   132         } else {  /* shouldn't happen, but just in case... */
   133             SDL_free(retval);
   134             retval = NULL;
   135         }
   136     }
   137 
   138     if (retval != NULL) {
   139         /* try to shrink buffer... */
   140         char *ptr = (char *) SDL_realloc(retval, strlen(retval) + 1);
   141         if (ptr != NULL)
   142             retval = ptr;  /* oh well if it failed. */
   143     }
   144 
   145     return retval;
   146 }
   147 
   148 char *
   149 SDL_GetPrefPath(const char *org, const char *app)
   150 {
   151     /*
   152      * We use XDG's base directory spec, even if you're not on Linux.
   153      *  This isn't strictly correct, but the results are relatively sane
   154      *  in any case.
   155      *
   156      * http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
   157      */
   158     const char *envr = SDL_getenv("XDG_DATA_HOME");
   159     const char *append;
   160     char *retval = NULL;
   161     char *ptr = NULL;
   162     size_t len = 0;
   163 
   164     if (!envr) {
   165         /* You end up with "$HOME/.local/share/Game Name 2" */
   166         envr = SDL_getenv("HOME");
   167         if (!envr) {
   168             /* we could take heroic measures with /etc/passwd, but oh well. */
   169             SDL_SetError("neither XDG_DATA_HOME nor HOME environment is set");
   170             return NULL;
   171         }
   172         append = "/.local/share/";
   173     } else {
   174         append = "/";
   175     }
   176 
   177     len = SDL_strlen(envr);
   178     if (envr[len - 1] == '/')
   179         append += 1;
   180 
   181     len += SDL_strlen(append) + SDL_strlen(org) + SDL_strlen(app) + 3;
   182     retval = (char *) SDL_malloc(len);
   183     if (!retval) {
   184         SDL_OutOfMemory();
   185         return NULL;
   186     }
   187 
   188     SDL_snprintf(retval, len, "%s%s%s/%s/", envr, append, org, app);
   189 
   190     for (ptr = retval+1; *ptr; ptr++) {
   191         if (*ptr == '/') {
   192             *ptr = '\0';
   193             if (mkdir(retval, 0700) != 0 && errno != EEXIST)
   194                 goto error;
   195             *ptr = '/';
   196         }
   197     }
   198     if (mkdir(retval, 0700) != 0 && errno != EEXIST) {
   199 error:
   200         SDL_SetError("Couldn't create directory '%s': '%s'", retval, strerror(errno));
   201         SDL_free(retval);
   202         return NULL;
   203     }
   204 
   205     return retval;
   206 }
   207 
   208 #endif /* SDL_FILESYSTEM_UNIX */
   209 
   210 /* vi: set ts=4 sw=4 expandtab: */