games/gog: Add Freedom Planet version 1.21.5

A game that I had laying around since quite a while but I was too lazy
to patch properly, since the game expects its data files as well as its
save files in the current working directory.

While I did patch the game via an LD_PRELOAD wrapper of fopen it also
feels kinda rendundant with code we have in preloaders of other games.

So in the long term we might want to implement something a bit more
generic, but for now the game works and config and saves are properly
placed in XDG_CONFIG_HOME and XDG_DATA_HOME.

Signed-off-by: aszlig <aszlig@nix.build>

2 files changed, 118 insertions, 0 deletions

diff --git a/pkgs/games/gog/default.nix b/pkgs/games/gog/default.nix
index aa672b4f..723392b7 100644
--- a/pkgs/games/gog/default.nix
+++ b/pkgs/games/gog/default.nix
@@ -15,6 +15,7 @@ let
     crosscode = callPackage ./crosscode.nix {};
     dungeons3 = callPackage ./dungeons3.nix {};
     epistory = callPackage ./epistory.nix { };
+    freedom-planet = callPackage ./freedom-planet.nix {};
     homm3 = callPackage ./homm3 {};
     kingdoms-and-castles = callPackage ./kingdoms-and-castles.nix {};
     overload = callPackage ./overload.nix {};
diff --git a/pkgs/games/gog/freedom-planet.nix b/pkgs/games/gog/freedom-planet.nix
new file mode 100644
index 00000000..05a9b869
--- /dev/null
+++ b/pkgs/games/gog/freedom-planet.nix
@@ -0,0 +1,117 @@
+{ stdenv, buildGame, fetchGog, writeText, SDL2, libudev }:
+
+buildGame rec {
+  name = "freedom-planet-${version}";
+  version = "1.21.5";
+
+  src = fetchGog {
+    productId = 1207667013;
+    downloadName = "en3installer0";
+    sha256 = "1rsa2bswzvc4a8crpzhcw3vjan0f9avk7g1gyqibnyppib63i42w";
+  };
+
+  binDir = "bin${if stdenv.is64bit then "64" else "32"}";
+  buildInputs = [ SDL2 ];
+  runtimeDependencies = [ libudev ];
+
+  buildPhase = ''
+    cc -Werror -Wall -std=gnu11 -shared "$preloader" -o preload.so -fPIC \
+      -DDATA_DIR="\"$out/share/freedom-planet\""
+    patchelf \
+      --add-needed "$out/libexec/freedom-planet/libpreload.so" \
+      "$binDir/Chowdren"
+  '';
+
+  preloader = writeText "freedom-planet-preloader.c" ''
+    #define _GNU_SOURCE
+    #include <dlfcn.h>
+    #include <stdio.h>
+    #include <stdlib.h>
+    #include <string.h>
+
+    static char *mkDataPath(const char *path)
+    {
+      size_t pathlen;
+      char *buf;
+
+      pathlen = strlen(path);
+      buf = malloc(pathlen + sizeof(DATA_DIR));
+      if (buf == NULL) return NULL;
+
+      memcpy(buf, DATA_DIR, sizeof(DATA_DIR) - 1);
+      memcpy(buf + sizeof(DATA_DIR) - 1, path, pathlen + 1);
+
+      return buf;
+    }
+
+    static char *mkSavePath(const char *path)
+    {
+      char *env;
+      char *buf;
+
+      if ((env = getenv("XDG_DATA_HOME")) != NULL) {
+        if (asprintf(&buf, "%s/freedom-planet%s", env, path + 1) == -1)
+          return NULL;
+      } else if ((env = getenv("HOME")) != NULL) {
+        if (asprintf(&buf, "%s/.local/share/freedom-planet%s", env,
+                     path + 1) == -1)
+          return NULL;
+      }
+
+      return buf;
+    }
+
+    static char *mkCfgPath(const char *path)
+    {
+      char *env;
+      char *buf;
+
+      if ((env = getenv("XDG_CONFIG_HOME")) != NULL) {
+        if (asprintf(&buf, "%s/freedom-planet%s", env, path + 1) == -1)
+          return NULL;
+      } else if ((env = getenv("HOME")) != NULL) {
+        if (asprintf(&buf, "%s/.config/freedom-planet%s", env, path + 1) == -1)
+          return NULL;
+      }
+
+      return buf;
+    }
+
+    FILE *fopen(const char *path, const char *mode) {
+      FILE *ret;
+      char *buf;
+
+      static FILE *(*_fopen) (const char *, const char *) = NULL;
+      if (_fopen == NULL) _fopen = dlsym(RTLD_NEXT, "fopen");
+
+      if (strncmp(path, "./Assets.dat", 13) == 0) {
+        buf = mkDataPath(path + 1);
+      } else if (strncmp(path, "./Data/", 7) == 0) {
+        buf = mkDataPath(path + 6);
+      } else if (strncmp(path, "./records.dat", 14) == 0 ||
+                 strncmp(path, "./file", 6) == 0 ||
+                 strncmp(path, "./save", 6) == 0) {
+        buf = mkSavePath(path);
+      } else if (strncmp(path, "./control_", 10) == 0) {
+        buf = mkCfgPath(path);
+      } else {
+        return _fopen(path, mode);
+      }
+      if (buf == NULL) return NULL;
+      ret = fopen(buf, mode);
+      free(buf);
+      return ret;
+    }
+  '';
+
+  installPhase = ''
+    install -m 0644 -vD Assets.dat "$out/share/freedom-planet/Assets.dat"
+    install -vD "$binDir/Chowdren" "$out/bin/freedom-planet"
+    install -vD preload.so "$out/libexec/freedom-planet/libpreload.so"
+    cp -rt "$out/share/freedom-planet" Data/BGM Data/font.bmp Data/voices
+  '';
+
+  sandbox.paths.required = [
+    "$XDG_DATA_HOME/freedom-planet" "$XDG_CONFIG_HOME/freedom-planet"
+  ];
+}