text: /*
   * 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
  
  #include <ctype.h>
  #include <ftw.h>
  #include <string.h>
  #include <stdlib.h>
  #include <stdio.h>
  #include <sys/file.h>
  #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>
  #include "zlib.h"
  
  #ifdef HAVE_ZSTD
  #include "zstd.h"
  #endif
  
  #include "util/crc32.h"
  #include "util/debug.h"
  #include "util/rand_xor.h"
  #include "util/u_atomic.h"
  #include "util/u_queue.h"
  #include "util/mesa-sha1.h"
  #include "util/ralloc.h"
  #include "main/compiler.h"
  #include "main/errors.h"
  
  #include "disk_cache.h"
  
  /* Number of bits to mask off from a cache key to get an index. */
  #define CACHE_INDEX_KEY_BITS 16
  
  /* Mask for computing an index from a key. */
  #define CACHE_INDEX_KEY_MASK ((1 << CACHE_INDEX_KEY_BITS) - 1)
  
  /* The number of keys that can be stored in the index. */
  #define CACHE_INDEX_MAX_KEYS (1 << CACHE_INDEX_KEY_BITS)
  
  /* The cache version should be bumped whenever a change is made to the
   * structure of cache entries or the index. This will give any 3rd party
   * applications reading the cache entries a chance to adjust to the changes.
   *
   * - The cache version is checked internally when reading a cache entry. If we
   *   ever have a mismatch we are in big trouble as this means we had a cache
   *   collision. In case of such an event please check the skys for giant
   *   asteroids and that the entire Mesa team hasn't been eaten by wolves.
   *
   * - There is no strict requirement that cache versions be backwards
   *   compatible but effort should be taken to limit disruption where possible.
   */
  #define CACHE_VERSION 1
  
  /* 3 is the recomended level, with 22 as the absolute maximum */
  #define ZSTD_COMPRESSION_LEVEL 3
  
  struct disk_cache {
     /* The path to the cache directory. */
     char *path;
     bool path_init_failed;
  
     /* Thread queue for compressing and writing cache entries to disk */
     struct util_queue cache_queue;
  
     /* Seed for rand, which is used to pick a random directory */
     uint64_t seed_xorshift128plus[2];
  
     /* A pointer to the mmapped index file within the cache directory. */
     uint8_t *index_mmap;
     size_t index_mmap_size;
  
     /* Pointer to total size of all objects in cache (within index_mmap) */
     uint64_t *size;
  
     /* Pointer to stored keys, (within index_mmap). */
     uint8_t *stored_keys;
  
     /* Maximum size of all cached objects (in bytes). */
     uint64_t max_size;
  
     /* Driver cache keys. */
     uint8_t *driver_keys_blob;
     size_t driver_keys_blob_size;
  
     disk_cache_put_cb blob_put_cb;
     disk_cache_get_cb blob_get_cb;
  };
  
  struct disk_cache_put_job {
     struct util_queue_fence fence;
  
     struct disk_cache *cache;
  
     cache_key key;
  
     /* Copy of cache data to be compressed and written. */
     void *data;
  
     /* Size of data to be compressed and written. */
     size_t size;
  
     struct cache_item_metadata cache_item_metadata;
  };
  
  /* 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;
  }
  
  #define DRV_KEY_CPY(_dst, _src, _src_size) \
  do {                                       \
     memcpy(_dst, _src, _src_size);          \
     _dst += _src_size;                      \
  } while (0);
  
  struct disk_cache *
  disk_cache_create(const char *gpu_name, const char *driver_id,
                    uint64_t driver_flags)
  {
     void *local;
     struct disk_cache *cache = NULL;
     char *path, *max_size_str;
     uint64_t max_size;
     int fd = -1;
     struct stat sb;
     size_t size;
  
     uint8_t cache_version = CACHE_VERSION;
     size_t cv_size = sizeof(cache_version);
  
     /* If running as a users other than the real user disable cache */
     if (geteuid() != getuid())
        return NULL;
  
     /* A ralloc context for transient data during this invocation. */
     local = ralloc_context(NULL);
     if (local == NULL)
        goto fail;
  
     /* At user request, disable shader cache entirely. */
     if (env_var_as_boolean("MESA_GLSL_CACHE_DISABLE", false))
        goto fail;
  
     cache = rzalloc(NULL, struct disk_cache);
     if (cache == NULL)
        goto fail;
  
     /* Assume failure. */
     cache->path_init_failed = true;
  
     /* 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
      */
     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;
  
     path = ralloc_asprintf(local, "%s/index", cache->path);
     if (path == NULL)
        goto path_fail;
  
     fd = open(path, O_RDWR | O_CREAT | O_CLOEXEC, 0644);
     if (fd == -1)
        goto path_fail;
  
     if (fstat(fd, &sb) == -1)
        goto path_fail;
  
     /* Force the index file to be the expected size. */
     size = sizeof(*cache->size) + CACHE_INDEX_MAX_KEYS * CACHE_KEY_SIZE;
     if (sb.st_size != size) {
        if (ftruncate(fd, size) == -1)
           goto path_fail;
     }
  
     /* We map this shared so that other processes see updates that we
      * make.
      *
      * Note: We do use atomic addition to ensure that multiple
      * processes don't scramble the cache size recorded in the
      * index. But we don't use any locking to prevent multiple
      * processes from updating the same entry simultaneously. The idea
      * is that if either result lands entirely in the index, then
      * that's equivalent to a well-ordered write followed by an
      * eviction and a write. On the other hand, if the simultaneous
      * writes result in a corrupt entry, that's not really any
      * different than both entries being evicted, (since within the
      * guarantees of the cryptographic hash, a corrupt entry is
      * unlikely to ever match a real cache key).
      */
     cache->index_mmap = mmap(NULL, size, PROT_READ | PROT_WRITE,
                              MAP_SHARED, fd, 0);
     if (cache->index_mmap == MAP_FAILED)
        goto path_fail;
     cache->index_mmap_size = size;
  
     cache->size = (uint64_t *) cache->index_mmap;
     cache->stored_keys = cache->index_mmap + sizeof(uint64_t);
  
     max_size = 0;
  
     max_size_str = getenv("MESA_GLSL_CACHE_MAX_SIZE");
     if (max_size_str) {
        char *end;
        max_size = strtoul(max_size_str, &end, 10);
        if (end == max_size_str) {
           max_size = 0;
        } else {
           switch (*end) {
           case 'K':
           case 'k':
              max_size *= 1024;
              break;
           case 'M':
           case 'm':
              max_size *= 1024*1024;
              break;
           case '\0':
           case 'G':
           case 'g':
           default:
              max_size *= 1024*1024*1024;
              break;
           }
        }
     }
  
     /* Default to 1GB for maximum cache size. */
     if (max_size == 0) {
        max_size = 1024*1024*1024;
     }
  
     cache->max_size = max_size;
  
     /* 4 threads were chosen below because just about all modern CPUs currently
      * available that run Mesa have *at least* 4 cores. For these CPUs allowing
      * more threads can result in the queue being processed faster, thus
      * avoiding excessive memory use due to a backlog of cache entrys building
      * up in the queue. Since we set the UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY
      * flag this should have little negative impact on low core systems.
      *
      * The queue will resize automatically when it's full, so adding new jobs
      * doesn't stall.
      */
     util_queue_init(&cache->cache_queue, "disk$", 32, 4,
                     UTIL_QUEUE_INIT_RESIZE_IF_FULL |
                     UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY |
                     UTIL_QUEUE_INIT_SET_FULL_THREAD_AFFINITY);
  
     cache->path_init_failed = false;
  
   path_fail:
  
     if (fd != -1)
        close(fd);
  
     cache->driver_keys_blob_size = cv_size;
  
     /* Create driver id keys */
     size_t id_size = strlen(driver_id) + 1;
     size_t gpu_name_size = strlen(gpu_name) + 1;
     cache->driver_keys_blob_size += id_size;
     cache->driver_keys_blob_size += gpu_name_size;
  
     /* We sometimes store entire structs that contains a pointers in the cache,
      * use pointer size as a key to avoid hard to debug issues.
      */
     uint8_t ptr_size = sizeof(void *);
     size_t ptr_size_size = sizeof(ptr_size);
     cache->driver_keys_blob_size += ptr_size_size;
  
     size_t driver_flags_size = sizeof(driver_flags);
     cache->driver_keys_blob_size += driver_flags_size;
  
     cache->driver_keys_blob =
        ralloc_size(cache, cache->driver_keys_blob_size);
     if (!cache->driver_keys_blob)
        goto fail;
  
     uint8_t *drv_key_blob = cache->driver_keys_blob;
     DRV_KEY_CPY(drv_key_blob, &cache_version, cv_size)
     DRV_KEY_CPY(drv_key_blob, driver_id, id_size)
     DRV_KEY_CPY(drv_key_blob, gpu_name, gpu_name_size)
     DRV_KEY_CPY(drv_key_blob, &ptr_size, ptr_size_size)
     DRV_KEY_CPY(drv_key_blob, &driver_flags, driver_flags_size)
  
     /* Seed our rand function */
     s_rand_xorshift128plus(cache->seed_xorshift128plus, true);
  
     ralloc_free(local);
  
     return cache;
  
   fail:
     if (cache)
        ralloc_free(cache);
     ralloc_free(local);
  
     return NULL;
  }
  
  void
  disk_cache_destroy(struct disk_cache *cache)
  {
     if (cache && !cache->path_init_failed) {
        util_queue_finish(&cache->cache_queue);
        util_queue_destroy(&cache->cache_queue);
        munmap(cache->index_mmap, cache->index_mmap_size);
     }
  
     ralloc_free(cache);
  }
  
  /* Return a filename within the cache's directory corresponding to 'key'. The
   * returned filename is ralloced with 'cache' as the parent context.
   *
   * Returns NULL if out of memory.
   */
  static char *
  get_cache_file(struct disk_cache *cache, const cache_key key)
  {
     char buf[41];
     char *filename;
  
     if (cache->path_init_failed)
        return NULL;
  
     _mesa_sha1_format(buf, key);
     if (asprintf(&filename, "%s/%c%c/%s", cache->path, buf[0],
                  buf[1], buf + 2) == -1)
        return NULL;
  
     return filename;
  }
  
  /* Create the directory that will be needed for the cache file for \key.
   *
   * Obviously, the implementation here must closely match
   * _get_cache_file above.
  */
  static void
  make_cache_file_directory(struct disk_cache *cache, const cache_key key)
  {
     char *dir;
     char buf[41];
  
     _mesa_sha1_format(buf, key);
     if (asprintf(&dir, "%s/%c%c", cache->path, buf[0], buf[1]) == -1)
        return;
  
     mkdir_if_needed(dir);
     free(dir);
  }
  
  /* Given a directory path and predicate function, find the entry with
   * the oldest access time in that directory for which the predicate
   * returns true.
   *
   * Returns: A malloc'ed string for the path to the chosen file, (or
   * NULL on any error). The caller should free the string when
   * finished.
   */
  static char *
  choose_lru_file_matching(const char *dir_path,
                           bool (*predicate)(const char *dir_path,
                                             const struct stat *,
                                             const char *, const size_t))
  {
     DIR *dir;
     struct dirent *entry;
     char *filename;
     char *lru_name = NULL;
     time_t lru_atime = 0;
  
     dir = opendir(dir_path);
     if (dir == NULL)
        return NULL;
  
     while (1) {
        entry = readdir(dir);
        if (entry == NULL)
           break;
  
        struct stat sb;
        if (fstatat(dirfd(dir), entry->d_name, &sb, 0) == 0) {
           if (!lru_atime || (sb.st_atime < lru_atime)) {
              size_t len = strlen(entry->d_name);
  
              if (!predicate(dir_path, &sb, entry->d_name, len))
                 continue;
  
              char *tmp = realloc(lru_name, len + 1);
              if (tmp) {
                 lru_name = tmp;
                 memcpy(lru_name, entry->d_name, len + 1);
                 lru_atime = sb.st_atime;
              }
           }
        }
     }
  
     if (lru_name == NULL) {
        closedir(dir);
        return NULL;
     }
  
     if (asprintf(&filename, "%s/%s", dir_path, lru_name) < 0)
        filename = NULL;
  
     free(lru_name);
     closedir(dir);
  
     return filename;
  }
  
  /* Is entry a regular file, and not having a name with a trailing
   * ".tmp"
   */
  static bool
  is_regular_non_tmp_file(const char *path, const struct stat *sb,
                          const char *d_name, const size_t len)
  {
     if (!S_ISREG(sb->st_mode))
        return false;
  
     if (len >= 4 && strcmp(&d_name[len-4], ".tmp") == 0)
        return false;
  
     return true;
  }
  
  /* Returns the size of the deleted file, (or 0 on any error). */
  static size_t
  unlink_lru_file_from_directory(const char *path)
  {
     struct stat sb;
     char *filename;
  
     filename = choose_lru_file_matching(path, is_regular_non_tmp_file);
     if (filename == NULL)
        return 0;
  
     if (stat(filename, &sb) == -1) {
        free (filename);
        return 0;
     }
  
     unlink(filename);
     free (filename);
  
     return sb.st_blocks * 512;
  }
  
  /* Is entry a directory with a two-character name, (and not the
   * special name of ".."). We also return false if the dir is empty.
   */
  static bool
  is_two_character_sub_directory(const char *path, const struct stat *sb,
                                 const char *d_name, const size_t len)
  {
     if (!S_ISDIR(sb->st_mode))
        return false;
  
     if (len != 2)
        return false;
  
     if (strcmp(d_name, "..") == 0)
        return false;
  
     char *subdir;
     if (asprintf(&subdir, "%s/%s", path, d_name) == -1)
        return false;
     DIR *dir = opendir(subdir);
     free(subdir);
  
     if (dir == NULL)
       return false;
  
     unsigned subdir_entries = 0;
     struct dirent *d;
     while ((d = readdir(dir)) != NULL) {
        if(++subdir_entries > 2)
           break;
     }
     closedir(dir);
  
     /* If dir only contains '.' and '..' it must be empty */
     if (subdir_entries <= 2)
        return false;
  
     return true;
  }
  
  static void
  evict_lru_item(struct disk_cache *cache)
  {
     char *dir_path;
  
     /* With a reasonably-sized, full cache, (and with keys generated
      * from a cryptographic hash), we can choose two random hex digits
      * and reasonably expect the directory to exist with a file in it.
      * Provides pseudo-LRU eviction to reduce checking all cache files.
      */
     uint64_t rand64 = rand_xorshift128plus(cache->seed_xorshift128plus);
     if (asprintf(&dir_path, "%s/%02" PRIx64 , cache->path, rand64 & 0xff) < 0)
        return;
  
     size_t size = unlink_lru_file_from_directory(dir_path);
  
     free(dir_path);
  
     if (size) {
        p_atomic_add(cache->size, - (uint64_t)size);
        return;
     }
  
     /* In the case where the random choice of directory didn't find
      * something, we choose the least recently accessed from the
      * existing directories.
      *
      * Really, the only reason this code exists is to allow the unit
      * tests to work, (which use an artificially-small cache to be able
      * to force a single cached item to be evicted).
      */
     dir_path = choose_lru_file_matching(cache->path,
                                         is_two_character_sub_directory);
     if (dir_path == NULL)
        return;
  
     size = unlink_lru_file_from_directory(dir_path);
  
     free(dir_path);
  
     if (size)
        p_atomic_add(cache->size, - (uint64_t)size);
  }
  
  void
  disk_cache_remove(struct disk_cache *cache, const cache_key key)
  {
     struct stat sb;
  
     char *filename = get_cache_file(cache, key);
     if (filename == NULL) {
        return;
     }
  
     if (stat(filename, &sb) == -1) {
        free(filename);
        return;
     }
  
     unlink(filename);
     free(filename);
  
     if (sb.st_blocks)
        p_atomic_add(cache->size, - (uint64_t)sb.st_blocks * 512);
  }
  
  static ssize_t
  read_all(int fd, void *buf, size_t count)
  {
     char *in = buf;
     ssize_t read_ret;
     size_t done;
  
     for (done = 0; done < count; done += read_ret) {
        read_ret = read(fd, in + done, count - done);
        if (read_ret == -1 || read_ret == 0)
           return -1;
     }
     return done;
  }
  
  static ssize_t
  write_all(int fd, const void *buf, size_t count)
  {
     const char *out = buf;
     ssize_t written;
     size_t done;
  
     for (done = 0; done < count; done += written) {
        written = write(fd, out + done, count - done);
        if (written == -1)
           return -1;
     }
     return done;
  }
  
  /* From the zlib docs:
   *    "If the memory is available, buffers sizes on the order of 128K or 256K
   *    bytes should be used."
   */
  #define BUFSIZE 256 * 1024
  
  /**
   * Compresses cache entry in memory and writes it to disk. Returns the size
   * of the data written to disk.
   */
  static size_t
  deflate_and_write_to_disk(const void *in_data, size_t in_data_size, int dest,
                            const char *filename)
  {
  #ifdef HAVE_ZSTD
     /* from the zstd docs (https://facebook.github.io/zstd/zstd_manual.html):
      * compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
      */
     size_t out_size = ZSTD_compressBound(in_data_size);
     void * out = malloc(out_size);
  
     size_t ret = ZSTD_compress(out, out_size, in_data, in_data_size,
                                ZSTD_COMPRESSION_LEVEL);
     if (ZSTD_isError(ret)) {
        free(out);
        return 0;
     }
     ssize_t written = write_all(dest, out, ret);
     if (written == -1) {
        free(out);
        return 0;
     }
     free(out);
     return ret;
  #else
     unsigned char *out;
  
     /* allocate deflate state */
     z_stream strm;
     strm.zalloc = Z_NULL;
     strm.zfree = Z_NULL;
     strm.opaque = Z_NULL;
     strm.next_in = (uint8_t *) in_data;
     strm.avail_in = in_data_size;
  
     int ret = deflateInit(&strm, Z_BEST_COMPRESSION);
     if (ret != Z_OK)
         return 0;
  
     /* compress until end of in_data */
     size_t compressed_size = 0;
     int flush;
  
     out = malloc(BUFSIZE * sizeof(unsigned char));
     if (out == NULL)
        return 0;
  
     do {
        int remaining = in_data_size - BUFSIZE;
        flush = remaining > 0 ? Z_NO_FLUSH : Z_FINISH;
        in_data_size -= BUFSIZE;
  
        /* Run deflate() on input until the output buffer is not full (which
         * means there is no more data to deflate).
         */
        do {
           strm.avail_out = BUFSIZE;
           strm.next_out = out;
  
           ret = deflate(&strm, flush);    /* no bad return value */
           assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
  
           size_t have = BUFSIZE - strm.avail_out;
           compressed_size += have;
  
           ssize_t written = write_all(dest, out, have);
           if (written == -1) {
              (void)deflateEnd(&strm);
              free(out);
              return 0;
           }
        } while (strm.avail_out == 0);
  
        /* all input should be used */
        assert(strm.avail_in == 0);
  
     } while (flush != Z_FINISH);
  
     /* stream should be complete */
     assert(ret == Z_STREAM_END);
  
     /* clean up and return */
     (void)deflateEnd(&strm);
     free(out);
     return compressed_size;
  # endif
  }
  
  static struct disk_cache_put_job *
  create_put_job(struct disk_cache *cache, const cache_key key,
                 const void *data, size_t size,
                 struct cache_item_metadata *cache_item_metadata)
  {
     struct disk_cache_put_job *dc_job = (struct disk_cache_put_job *)
        malloc(sizeof(struct disk_cache_put_job) + size);
  
     if (dc_job) {
        dc_job->cache = cache;
        memcpy(dc_job->key, key, sizeof(cache_key));
        dc_job->data = dc_job + 1;
        memcpy(dc_job->data, data, size);
        dc_job->size = size;
  
        /* Copy the cache item metadata */
        if (cache_item_metadata) {
           dc_job->cache_item_metadata.type = cache_item_metadata->type;
           if (cache_item_metadata->type == CACHE_ITEM_TYPE_GLSL) {
              dc_job->cache_item_metadata.num_keys =
                 cache_item_metadata->num_keys;
              dc_job->cache_item_metadata.keys = (cache_key *)
                 malloc(cache_item_metadata->num_keys * sizeof(cache_key));
  
              if (!dc_job->cache_item_metadata.keys)
                 goto fail;
  
              memcpy(dc_job->cache_item_metadata.keys,
                     cache_item_metadata->keys,
                     sizeof(cache_key) * cache_item_metadata->num_keys);
           }
        } else {
           dc_job->cache_item_metadata.type = CACHE_ITEM_TYPE_UNKNOWN;
           dc_job->cache_item_metadata.keys = NULL;
        }
     }
  
     return dc_job;
  
  fail:
     free(dc_job);
  
     return NULL;
  }
  
  static void
  destroy_put_job(void *job, int thread_index)
  {
     if (job) {
        struct disk_cache_put_job *dc_job = (struct disk_cache_put_job *) job;
        free(dc_job->cache_item_metadata.keys);
  
        free(job);
     }
  }
  
  struct cache_entry_file_data {
     uint32_t crc32;
     uint32_t uncompressed_size;
  };
  
  static void
  cache_put(void *job, int thread_index)
  {
     assert(job);
  
     int fd = -1, fd_final = -1, err, ret;
     unsigned i = 0;
     char *filename = NULL, *filename_tmp = NULL;
     struct disk_cache_put_job *dc_job = (struct disk_cache_put_job *) job;
  
     filename = get_cache_file(dc_job->cache, dc_job->key);
     if (filename == NULL)
        goto done;
  
     /* If the cache is too large, evict something else first. */
     while (*dc_job->cache->size + dc_job->size > dc_job->cache->max_size &&
            i < 8) {
        evict_lru_item(dc_job->cache);
        i++;
     }
  
     /* Write to a temporary file to allow for an atomic rename to the
      * final destination filename, (to prevent any readers from seeing
      * a partially written file).
      */
     if (asprintf(&filename_tmp, "%s.tmp", filename) == -1)
        goto done;
  
     fd = open(filename_tmp, O_WRONLY | O_CLOEXEC | O_CREAT, 0644);
  
     /* Make the two-character subdirectory within the cache as needed. */
     if (fd == -1) {
        if (errno != ENOENT)
           goto done;
  
        make_cache_file_directory(dc_job->cache, dc_job->key);
  
        fd = open(filename_tmp, O_WRONLY | O_CLOEXEC | O_CREAT, 0644);
        if (fd == -1)
           goto done;
     }
  
     /* With the temporary file open, we take an exclusive flock on
      * it. If the flock fails, then another process still has the file
      * open with the flock held. So just let that file be responsible
      * for writing the file.
      */
  #ifdef HAVE_FLOCK
     err = flock(fd, LOCK_EX | LOCK_NB);
  #else
     struct flock lock = {
        .l_start = 0,
        .l_len = 0, /* entire file */
        .l_type = F_WRLCK,
        .l_whence = SEEK_SET
     };
     err = fcntl(fd, F_SETLK, &lock);
  #endif
     if (err == -1)
        goto done;
  
     /* Now that we have the lock on the open temporary file, we can
      * check to see if the destination file already exists. If so,
      * another process won the race between when we saw that the file
      * didn't exist and now. In this case, we don't do anything more,
      * (to ensure the size accounting of the cache doesn't get off).
      */
     fd_final = open(filename, O_RDONLY | O_CLOEXEC);
     if (fd_final != -1) {
        unlink(filename_tmp);
        goto done;
     }
  
     /* OK, we're now on the hook to write out a file that we know is
      * not in the cache, and is also not being written out to the cache
      * by some other process.
      */
  
     /* Write the driver_keys_blob, this can be used find information about the
      * mesa version that produced the entry or deal with hash collisions,
      * should that ever become a real problem.
      */
     ret = write_all(fd, dc_job->cache->driver_keys_blob,
                     dc_job->cache->driver_keys_blob_size);
     if (ret == -1) {
        unlink(filename_tmp);
        goto done;
     }
  
     /* Write the cache item metadata. This data can be used to deal with
      * hash collisions, as well as providing useful information to 3rd party
      * tools reading the cache files.
      */
     ret = write_all(fd, &dc_job->cache_item_metadata.type,
                     sizeof(uint32_t));
     if (ret == -1) {
        unlink(filename_tmp);
        goto done;
     }
  
     if (dc_job->cache_item_metadata.type == CACHE_ITEM_TYPE_GLSL) {
        ret = write_all(fd, &dc_job->cache_item_metadata.num_keys,
                        sizeof(uint32_t));
        if (ret == -1) {
           unlink(filename_tmp);
           goto done;
        }
  
        ret = write_all(fd, dc_job->cache_item_metadata.keys[0],
                        dc_job->cache_item_metadata.num_keys *
                        sizeof(cache_key));
        if (ret == -1) {
           unlink(filename_tmp);
           goto done;
        }
     }
  
     /* Create CRC of the data. We will read this when restoring the cache and
      * use it to check for corruption.
      */
     struct cache_entry_file_data cf_data;
     cf_data.crc32 = util_hash_crc32(dc_job->data, dc_job->size);
     cf_data.uncompressed_size = dc_job->size;
  
     size_t cf_data_size = sizeof(cf_data);
     ret = write_all(fd, &cf_data, cf_data_size);
     if (ret == -1) {
        unlink(filename_tmp);
        goto done;
     }
  
     /* Now, finally, write out the contents to the temporary file, then
      * rename them atomically to the destination filename, and also
      * perform an atomic increment of the total cache size.
      */
     size_t file_size = deflate_and_write_to_disk(dc_job->data, dc_job->size,
                                                  fd, filename_tmp);
     if (file_size == 0) {
        unlink(filename_tmp);
        goto done;
     }
     ret = rename(filename_tmp, filename);
     if (ret == -1) {
        unlink(filename_tmp);
        goto done;
     }
  
     struct stat sb;
     if (stat(filename, &sb) == -1) {
        /* Something went wrong remove the file */
        unlink(filename);
        goto done;
     }
  
     p_atomic_add(dc_job->cache->size, sb.st_blocks * 512);
  
   done:
     if (fd_final != -1)
        close(fd_final);
     /* This close finally releases the flock, (now that the final file
      * has been renamed into place and the size has been added).
      */
     if (fd != -1)
        close(fd);
     free(filename_tmp);
     free(filename);
  }
  
  void
  disk_cache_put(struct disk_cache *cache, const cache_key key,
                 const void *data, size_t size,
                 struct cache_item_metadata *cache_item_metadata)
  {
     if (cache->blob_put_cb) {
        cache->blob_put_cb(key, CACHE_KEY_SIZE, data, size);
        return;
     }
  
     if (cache->path_init_failed)
        return;
  
     struct disk_cache_put_job *dc_job =
        create_put_job(cache, key, data, size, cache_item_metadata);
  
     if (dc_job) {
        util_queue_fence_init(&dc_job->fence);
        util_queue_add_job(&cache->cache_queue, dc_job, &dc_job->fence,
                           cache_put, destroy_put_job, dc_job->size);
     }
  }
  
  /**
   * Decompresses cache entry, returns true if successful.
   */
  static bool
  inflate_cache_data(uint8_t *in_data, size_t in_data_size,
                     uint8_t *out_data, size_t out_data_size)
  {
  #ifdef HAVE_ZSTD
     size_t ret = ZSTD_decompress(out_data, out_data_size, in_data, in_data_size);
     return !ZSTD_isError(ret);
  #else
     z_stream strm;
  
     /* allocate inflate state */
     strm.zalloc = Z_NULL;
     strm.zfree = Z_NULL;
     strm.opaque = Z_NULL;
     strm.next_in = in_data;
     strm.avail_in = in_data_size;
     strm.next_out = out_data;
     strm.avail_out = out_data_size;
  
     int ret = inflateInit(&strm);
     if (ret != Z_OK)
        return false;
  
     ret = inflate(&strm, Z_NO_FLUSH);
     assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
  
     /* Unless there was an error we should have decompressed everything in one
      * go as we know the uncompressed file size.
      */
     if (ret != Z_STREAM_END) {
        (void)inflateEnd(&strm);
        return false;
     }
     assert(strm.avail_out == 0);
  
     /* clean up and return */
     (void)inflateEnd(&strm);
     return true;
  #endif
  }
  
  void *
  disk_cache_get(struct disk_cache *cache, const cache_key key, size_t *size)
  {
     int fd = -1, ret;
     struct stat sb;
     char *filename = NULL;
     uint8_t *data = NULL;
     uint8_t *uncompressed_data = NULL;
     uint8_t *file_header = NULL;
  
     if (size)
        *size = 0;
  
     if (cache->blob_get_cb) {
        /* This is what Android EGL defines as the maxValueSize in egl_cache_t
         * class implementation.
         */
        const signed long max_blob_size = 64 * 1024;
        void *blob = malloc(max_blob_size);
        if (!blob)
           return NULL;
  
        signed long bytes =
           cache->blob_get_cb(key, CACHE_KEY_SIZE, blob, max_blob_size);
  
        if (!bytes) {
           free(blob);
           return NULL;
        }
  
        if (size)
           *size = bytes;
        return blob;
     }
  
     filename = get_cache_file(cache, key);
     if (filename == NULL)
        goto fail;
  
     fd = open(filename, O_RDONLY | O_CLOEXEC);
     if (fd == -1)
        goto fail;
  
     if (fstat(fd, &sb) == -1)
        goto fail;
  
     data = malloc(sb.st_size);
     if (data == NULL)
        goto fail;
  
     size_t ck_size = cache->driver_keys_blob_size;
     file_header = malloc(ck_size);
     if (!file_header)
        goto fail;
  
     if (sb.st_size < ck_size)
        goto fail;
  
     ret = read_all(fd, file_header, ck_size);
     if (ret == -1)
        goto fail;
  
     /* Check for extremely unlikely hash collisions */
     if (memcmp(cache->driver_keys_blob, file_header, ck_size) != 0) {
        assert(!"Mesa cache keys mismatch!");
        goto fail;
     }
  
     size_t cache_item_md_size = sizeof(uint32_t);
     uint32_t md_type;
     ret = read_all(fd, &md_type, cache_item_md_size);
     if (ret == -1)
        goto fail;
  
     if (md_type == CACHE_ITEM_TYPE_GLSL) {
        uint32_t num_keys;
        cache_item_md_size += sizeof(uint32_t);
        ret = read_all(fd, &num_keys, sizeof(uint32_t));
        if (ret == -1)
           goto fail;
  
        /* The cache item metadata is currently just used for distributing
         * precompiled shaders, they are not used by Mesa so just skip them for
         * now.
         * TODO: pass the metadata back to the caller and do some basic
         * validation.
         */
        cache_item_md_size += num_keys * sizeof(cache_key);
        ret = lseek(fd, num_keys * sizeof(cache_key), SEEK_CUR);
        if (ret == -1)
           goto fail;
     }
  
     /* Load the CRC that was created when the file was written. */
     struct cache_entry_file_data cf_data;
     size_t cf_data_size = sizeof(cf_data);
     ret = read_all(fd, &cf_data, cf_data_size);
     if (ret == -1)
        goto fail;
  
     /* Load the actual cache data. */
     size_t cache_data_size =
        sb.st_size - cf_data_size - ck_size - cache_item_md_size;
     ret = read_all(fd, data, cache_data_size);
     if (ret == -1)
        goto fail;
  
     /* Uncompress the cache data */
     uncompressed_data = malloc(cf_data.uncompressed_size);
     if (!inflate_cache_data(data, cache_data_size, uncompressed_data,
                             cf_data.uncompressed_size))
        goto fail;
  
     /* Check the data for corruption */
     if (cf_data.crc32 != util_hash_crc32(uncompressed_data,
                                          cf_data.uncompressed_size))
        goto fail;
  
     free(data);
     free(filename);
     free(file_header);
     close(fd);
  
     if (size)
        *size = cf_data.uncompressed_size;
  
     return uncompressed_data;
  
   fail:
     if (data)
        free(data);
     if (uncompressed_data)
        free(uncompressed_data);
     if (filename)
        free(filename);
     if (file_header)
        free(file_header);
     if (fd != -1)
        close(fd);
  
     return NULL;
  }
  
  void
  disk_cache_put_key(struct disk_cache *cache, const cache_key key)
  {
     const uint32_t *key_chunk = (const uint32_t *) key;
     int i = CPU_TO_LE32(*key_chunk) & CACHE_INDEX_KEY_MASK;
     unsigned char *entry;
  
     if (cache->blob_put_cb) {
        cache->blob_put_cb(key, CACHE_KEY_SIZE, key_chunk, sizeof(uint32_t));
        return;
     }
  
     if (cache->path_init_failed)
        return;
  
     entry = &cache->stored_keys[i * CACHE_KEY_SIZE];
  
     memcpy(entry, key, CACHE_KEY_SIZE);
  }
  
  /* This function lets us test whether a given key was previously
   * stored in the cache with disk_cache_put_key(). The implement is
   * efficient by not using syscalls or hitting the disk. It's not
   * race-free, but the races are benign. If we race with someone else
   * calling disk_cache_put_key, then that's just an extra cache miss and an
   * extra recompile.
   */
  bool
  disk_cache_has_key(struct disk_cache *cache, const cache_key key)
  {
     const uint32_t *key_chunk = (const uint32_t *) key;
     int i = CPU_TO_LE32(*key_chunk) & CACHE_INDEX_KEY_MASK;
     unsigned char *entry;
  
     if (cache->blob_get_cb) {
        uint32_t blob;
        return cache->blob_get_cb(key, CACHE_KEY_SIZE, &blob, sizeof(uint32_t));
     }
  
     if (cache->path_init_failed)
        return false;
  
     entry = &cache->stored_keys[i * CACHE_KEY_SIZE];
  
     return memcmp(entry, key, CACHE_KEY_SIZE) == 0;
  }
  
  void
  disk_cache_compute_key(struct disk_cache *cache, const void *data, size_t size,
                         cache_key key)
  {
     struct mesa_sha1 ctx;
  
     _mesa_sha1_init(&ctx);
     _mesa_sha1_update(&ctx, cache->driver_keys_blob,
                       cache->driver_keys_blob_size);
     _mesa_sha1_update(&ctx, data, size);
     _mesa_sha1_final(&ctx, key);
  }
  
  void
  disk_cache_set_callbacks(struct disk_cache *cache, disk_cache_put_cb put,
                           disk_cache_get_cb get)
  {
     cache->blob_put_cb = put;
     cache->blob_get_cb = get;
  }
  
  #endif /* ENABLE_SHADER_CACHE */
  