disk_cache: move cache dir generation into OS specific helper file

This will make windows support easier to add in future. To avoid code
churn this temporarily duplicates the mkdir_if_needed() function, we
will delete the duplicate in a following patch.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6197>

src/util/disk_cache.c

@@ -32,9 +32,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/mman.h>
-#include <unistd.h>
 #include <fcntl.h>
-#include <pwd.h>
 #include <errno.h>
 #include <dirent.h>
 #include <inttypes.h>
@@ -54,6 +52,7 @@
 #include "util/compiler.h"
 
 #include "disk_cache.h"
+#include "disk_cache_os.h"
 
 /* Number of bits to mask off from a cache key to get an index. */
 #define CACHE_INDEX_KEY_BITS 16
@@ -162,33 +161,6 @@ mkdir_if_needed(const char *path)
    return -1;
 }
 
-/* Concatenate an existing path and a new name to form a new path.  If the new
- * path does not exist as a directory, create it then return the resulting
- * name of the new path (ralloc'ed off of 'ctx').
- *
- * Returns NULL on any error, such as:
- *
- *      <path> does not exist or is not a directory
- *      <path>/<name> exists but is not a directory
- *      <path>/<name> cannot be created as a directory
- */
-static char *
-concatenate_and_mkdir(void *ctx, const char *path, const char *name)
-{
-   char *new_path;
-   struct stat sb;
-
-   if (stat(path, &sb) != 0 || ! S_ISDIR(sb.st_mode))
-      return NULL;
-
-   new_path = ralloc_asprintf(ctx, "%s/%s", path, name);
-
-   if (mkdir_if_needed(new_path) == 0)
-      return new_path;
-   else
-      return NULL;
-}
-
 #define DRV_KEY_CPY(_dst, _src, _src_size) \
 do {                                       \
    memcpy(_dst, _src, _src_size);          \
@@ -201,7 +173,7 @@ disk_cache_create(const char *gpu_name, const char *driver_id,
 {
    void *local;
    struct disk_cache *cache = NULL;
-   char *path, *max_size_str;
+   char *max_size_str;
    uint64_t max_size;
    int fd = -1;
    struct stat sb;
@@ -230,70 +202,10 @@ disk_cache_create(const char *gpu_name, const char *driver_id,
    /* Assume failure. */
    cache->path_init_failed = true;
 
-   /* Determine path for cache based on the first defined name as follows:
+   char *path = disk_cache_generate_cache_dir(local);
-    *
+   if (!path)
-    *   $MESA_GLSL_CACHE_DIR
-    *   $XDG_CACHE_HOME/mesa_shader_cache
-    *   <pwd.pw_dir>/.cache/mesa_shader_cache
-    */
-   path = getenv("MESA_GLSL_CACHE_DIR");
-   if (path) {
-      if (mkdir_if_needed(path) == -1)
       goto path_fail;
 
-      path = concatenate_and_mkdir(local, path, CACHE_DIR_NAME);
-      if (path == NULL)
-         goto path_fail;
-   }
-
-   if (path == NULL) {
-      char *xdg_cache_home = getenv("XDG_CACHE_HOME");
-
-      if (xdg_cache_home) {
-         if (mkdir_if_needed(xdg_cache_home) == -1)
-            goto path_fail;
-
-         path = concatenate_and_mkdir(local, xdg_cache_home, CACHE_DIR_NAME);
-         if (path == NULL)
-            goto path_fail;
-      }
-   }
-
-   if (path == NULL) {
-      char *buf;
-      size_t buf_size;
-      struct passwd pwd, *result;
-
-      buf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
-      if (buf_size == -1)
-         buf_size = 512;
-
-      /* Loop until buf_size is large enough to query the directory */
-      while (1) {
-         buf = ralloc_size(local, buf_size);
-
-         getpwuid_r(getuid(), &pwd, buf, buf_size, &result);
-         if (result)
-            break;
-
-         if (errno == ERANGE) {
-            ralloc_free(buf);
-            buf = NULL;
-            buf_size *= 2;
-         } else {
-            goto path_fail;
-         }
-      }
-
-      path = concatenate_and_mkdir(local, pwd.pw_dir, ".cache");
-      if (path == NULL)
-         goto path_fail;
-
-      path = concatenate_and_mkdir(local, path, CACHE_DIR_NAME);
-      if (path == NULL)
-         goto path_fail;
-   }
-
    cache->path = ralloc_strdup(cache, path);
    if (cache->path == NULL)
       goto path_fail;

src/util/disk_cache_os.c

@@ -0,0 +1,176 @@
+/*
+ * Copyright © 2014 Intel Corporation
+ *
+ * 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 (including the next
+ * paragraph) 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.
+ */
+
+#ifdef ENABLE_SHADER_CACHE
+
+#if DETECT_OS_WINDOWS
+/* TODO: implement disk cache support on windows */
+
+#else
+
+#include <errno.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "util/disk_cache.h"
+#include "util/disk_cache_os.h"
+#include "util/ralloc.h"
+
+/* Create a directory named 'path' if it does not already exist.
+ *
+ * Returns: 0 if path already exists as a directory or if created.
+ *         -1 in all other cases.
+ */
+static int
+mkdir_if_needed(const char *path)
+{
+   struct stat sb;
+
+   /* If the path exists already, then our work is done if it's a
+    * directory, but it's an error if it is not.
+    */
+   if (stat(path, &sb) == 0) {
+      if (S_ISDIR(sb.st_mode)) {
+         return 0;
+      } else {
+         fprintf(stderr, "Cannot use %s for shader cache (not a directory)"
+                         "---disabling.\n", path);
+         return -1;
+      }
+   }
+
+   int ret = mkdir(path, 0755);
+   if (ret == 0 || (ret == -1 && errno == EEXIST))
+     return 0;
+
+   fprintf(stderr, "Failed to create %s for shader cache (%s)---disabling.\n",
+           path, strerror(errno));
+
+   return -1;
+}
+
+/* Concatenate an existing path and a new name to form a new path.  If the new
+ * path does not exist as a directory, create it then return the resulting
+ * name of the new path (ralloc'ed off of 'ctx').
+ *
+ * Returns NULL on any error, such as:
+ *
+ *      <path> does not exist or is not a directory
+ *      <path>/<name> exists but is not a directory
+ *      <path>/<name> cannot be created as a directory
+ */
+static char *
+concatenate_and_mkdir(void *ctx, const char *path, const char *name)
+{
+   char *new_path;
+   struct stat sb;
+
+   if (stat(path, &sb) != 0 || ! S_ISDIR(sb.st_mode))
+      return NULL;
+
+   new_path = ralloc_asprintf(ctx, "%s/%s", path, name);
+
+   if (mkdir_if_needed(new_path) == 0)
+      return new_path;
+   else
+      return NULL;
+}
+
+/* Determine path for cache based on the first defined name as follows:
+ *
+ *   $MESA_GLSL_CACHE_DIR
+ *   $XDG_CACHE_HOME/mesa_shader_cache
+ *   <pwd.pw_dir>/.cache/mesa_shader_cache
+ */
+char *
+disk_cache_generate_cache_dir(void *mem_ctx)
+{
+   char *path = getenv("MESA_GLSL_CACHE_DIR");
+   if (path) {
+      if (mkdir_if_needed(path) == -1)
+         return NULL;
+
+      path = concatenate_and_mkdir(mem_ctx, path, CACHE_DIR_NAME);
+      if (!path)
+         return NULL;
+   }
+
+   if (path == NULL) {
+      char *xdg_cache_home = getenv("XDG_CACHE_HOME");
+
+      if (xdg_cache_home) {
+         if (mkdir_if_needed(xdg_cache_home) == -1)
+            return NULL;
+
+         path = concatenate_and_mkdir(mem_ctx, xdg_cache_home, CACHE_DIR_NAME);
+         if (!path)
+            return NULL;
+      }
+   }
+
+   if (!path) {
+      char *buf;
+      size_t buf_size;
+      struct passwd pwd, *result;
+
+      buf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
+      if (buf_size == -1)
+         buf_size = 512;
+
+      /* Loop until buf_size is large enough to query the directory */
+      while (1) {
+         buf = ralloc_size(mem_ctx, buf_size);
+
+         getpwuid_r(getuid(), &pwd, buf, buf_size, &result);
+         if (result)
+            break;
+
+         if (errno == ERANGE) {
+            ralloc_free(buf);
+            buf = NULL;
+            buf_size *= 2;
+         } else {
+            return NULL;
+         }
+      }
+
+      path = concatenate_and_mkdir(mem_ctx, pwd.pw_dir, ".cache");
+      if (!path)
+         return NULL;
+
+      path = concatenate_and_mkdir(mem_ctx, path, CACHE_DIR_NAME);
+      if (!path)
+         return NULL;
+   }
+
+   return path;
+}
+#endif
+
+#endif /* ENABLE_SHADER_CACHE */

src/util/disk_cache_os.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright © 2014 Intel Corporation
+ *
+ * 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 (including the next
+ * paragraph) 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.
+ */
+
+#ifndef DISK_CACHE_OS_H
+#define DISK_CACHE_OS_H
+
+#if DETECT_OS_WINDOWS
+
+/* TODO: implement disk cache support on windows */
+
+#else
+
+char *
+disk_cache_generate_cache_dir(void *mem_ctx);
+
+#endif
+
+#endif /* DISK_CACHE_OS_H */

src/util/meson.build

@@ -41,6 +41,8 @@ files_mesa_util = files(
   'debug.h',
   'disk_cache.c',
   'disk_cache.h',
+  'disk_cache_os.c',
+  'disk_cache_os.h',
   'double.c',
   'double.h',
   'enum_operators.h',