Fix temporary directory computation on linux (pr25147)

Summary:
On linux, the environment variables for temp directories that lldb checks for are generally not
defined, and the temp directory computation failed. This caused expression evaluation to fall
back to creating "/tmp/lldb-*.expr" debugging files instead of the usual
"$TMP/lldb/pid/lldb-*.expr". Crucially, these files were not cleaned up on lldb exit, which
caused clutter in the /tmp folder, especially on long-running machines (e.g. builtbots). This
commit fixes lldb to use llvm::sys::path::system_temp_directory, which does the same environment
variable dance, but (!) also falls back to the P_tmpdir macro, which is how the temp directory is
defined on linux.

Since the linux temp path computation now succeeds, I needed to also modify Android path
computation to check for actual directory existence, rather then checking whether the operation
failed.

Reviewers: clayborg, tberghammer

Subscribers: tberghammer, lldb-commits, danalbert, srhines, emaste

Differential Revision: http://reviews.llvm.org/D13772

llvm-svn: 250502

1 files changed, 9 insertions, 6 deletions

diff --git a/lldb/source/Host/android/HostInfoAndroid.cpp b/lldb/source/Host/android/HostInfoAndroid.cpp
index a5695f686a3..3fa50ec8ddf 100644
--- a/lldb/source/Host/android/HostInfoAndroid.cpp
+++ b/lldb/source/Host/android/HostInfoAndroid.cpp
@@ -91,11 +91,14 @@ HostInfoAndroid::ResolveLibraryPath(const std::string& module_path, const ArchSp
 bool
 HostInfoAndroid::ComputeTempFileBaseDirectory(FileSpec &file_spec)
 {
-    if (HostInfoLinux::ComputeTempFileBaseDirectory(file_spec))
-        return true;
+    bool success = HostInfoLinux::ComputeTempFileBaseDirectory(file_spec);
 
-    // If the default mechanism for computing the temp directory failed then
-    // fall back to /data/local/tmp
-    file_spec = FileSpec("/data/local/tmp", false);
-    return true;
+    // On Android, there is no path which is guaranteed to be writable. If the user has not
+    // provided a path via an environment variable, the generic algorithm will deduce /tmp, which
+    // is plain wrong. In that case we have an invalid directory, we substitute the path with
+    // /data/local/tmp, which is correct at least in some cases (i.e., when running as shell user).
+    if (!success || !file_spec.Exists())
+        file_spec = FileSpec("/data/local/tmp", false);
+
+    return file_spec.Exists();
 }