For MacOS and Windows, Java prefers the user's temporary directory for
java.io.tmpdir, but not for Linux, where it is always set to /tmp. The
burden with this is that if you want to use a different temp directory,
you have to explicitly pass -Djava.io.tmpdir=... on the command line,
which can be difficult especially for unit tests or microbenchmarks in
3rd party code ran via Maven for example.
java_props_t.tmp_dir is always initialized as P_tmpdir in
GetJavaProperties (src/java.base/unix/native/libjava/java_props_md.c).
The attached patch changed the behavior to use the content of the
environment variable TMPDIR, if present. Note that this does not change
where the hsperf* folders are created.
I'm not sure why java.io.tmpdir is always /tmp in Linux as according to
the SCM history, this was always as it is (references the initial
OpenJDK commit).
I haven't found any tests that validates the content of java.io.tmpdir.
Robert
--
Robert Stupp
@snazy
# HG changeset patch
# User Robert Stupp <sn...@snazy.de>
# Date 1524398509 -7200
# Sun Apr 22 14:01:49 2018 +0200
# Branch use-TMPDIR-env-Linux
# Node ID 3f9f58a5d4049fcba8e5201e321bf71984430ce9
# Parent fcd5df7aa235ca39852b04eb589e25f156870ce4
Use TMPDIR environment variable for java.io.tmpdir on Linux
diff --git a/src/java.base/unix/native/libjava/java_props_md.c
b/src/java.base/unix/native/libjava/java_props_md.c
--- a/src/java.base/unix/native/libjava/java_props_md.c
+++ b/src/java.base/unix/native/libjava/java_props_md.c
@@ -358,7 +358,7 @@
return &sprops;
}
- /* tmp dir */
+ /* tmp dir, use the default from _PATH_VARTMP */
sprops.tmp_dir = P_tmpdir;
#ifdef MACOSX
/* darwin has a per-user temp dir */
@@ -367,6 +367,14 @@
if (pathSize > 0 && pathSize <= PATH_MAX) {
sprops.tmp_dir = tmp_path;
}
+#else
+ /* Use the temporary directory injected via the environment variable TMPDIR
+ * instead of the "hard coded" _PATH_VARTMP
+ */
+ v = getenv("TMPDIR");
+ if (v) {
+ sprops.tmp_dir = strdup(v);
+ }
#endif /* MACOSX */
/* Printing properties */
