There is exactly one flock in mesa and it caused mesa not to build
on windows when shader cache was enabled.
It should be possible to revert 9f8dc3bf03ec825bae7041858dda6ca2e9a34363
"utils: build sha1/disk cache only with Android/Autoconf" currently
guarding the offending code with ENABLE_SHADER_CACHE
This would allow shader cache to work on windows I think.
I dont have a test system with windows though.
This builds on linux and is tested with Deus Ex:MD and Metro 2033 Redux
both with cold shader cache.
Really
Fixes: d1efa09d342bff3e5def2978a0bef748d74f9c82
CC: Tapani Pälli <tapani.pa...@intel.com>
CC: "Marek Olšák" <mar...@gmail.com>
CC: Emil Velikov <emil.l.veli...@gmail.com>
CC: Timothy Arceri <tarc...@itsqueeze.com>
CC: Samuel Pitoiset <samuel.pitoi...@gmail.com>
---
This enables the patch
[PATCH 1/3] mesa/main/shaderapi: Use generate_sha1() unconditionally
src/util/disk_cache.c | 48 +++++++++++++++++++++++++++++++++++-------------
1 file changed, 35 insertions(+), 13 deletions(-)
diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
index 4a762eff20..ca47bb15fb 100644
--- a/src/util/disk_cache.c
+++ b/src/util/disk_cache.c
@@ -28,7 +28,6 @@
#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>
@@ -848,6 +847,29 @@ struct cache_entry_file_data {
uint32_t uncompressed_size;
};
+static char *
+generate_random_string(int length) {
+ static const char a[] = "0123456789abcdef";
+
+ if (length > 16)
+ return NULL;
+
+ char buf[16];
+ char *rndstr;
+
+ for (int i = 0; i < length - 1; ++i) {
+ // assign a random element from the lookup table
+ buf[i] = a[rand() % (sizeof(a) - 1)];
+ }
+
+ buf[length - 1] = 0;
+
+ if (asprintf(&rndstr, "%s", buf) == -1)
+ return NULL;
+
+ return rndstr;
+}
+
static void
cache_put(void *job, int thread_index)
{
@@ -855,7 +877,7 @@ cache_put(void *job, int thread_index)
int fd = -1, fd_final = -1, err, ret;
unsigned i = 0;
- char *filename = NULL, *filename_tmp = NULL;
+ char *filename = NULL, *filename_tmp = NULL, *random = NULL;
struct disk_cache_put_job *dc_job = (struct disk_cache_put_job *) job;
filename = get_cache_file(dc_job->cache, dc_job->key);
@@ -873,7 +895,16 @@ cache_put(void *job, int thread_index)
* final destination filename, (to prevent any readers from seeing
* a partially written file).
*/
- if (asprintf(&filename_tmp, "%s.tmp", filename) == -1)
+
+ /* This next part used to be an flock(), which would prevent windows systems
+ * to build. 4 hex characters should be enough to prevent filename race
+ * conditions for now.
+ */
+ random = generate_random_string(4);
+ if (random == NULL)
+ goto done;
+
+ if (asprintf(&filename_tmp, "%s_%s.tmp", filename, random) == -1)
goto done;
fd = open(filename_tmp, O_WRONLY | O_CLOEXEC | O_CREAT, 0644);
@@ -890,16 +921,7 @@ cache_put(void *job, int thread_index)
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.
- */
- err = flock(fd, LOCK_EX | LOCK_NB);
- if (err == -1)
- goto done;
-
- /* Now that we have the lock on the open temporary file, we can
+ /* Now that we have 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,
--
2.14.1
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