Use getpwuid(getuid()) to determine the output root under Linux

Also Fallback the default ouput root to /var/tmp if $HOME is not set
under Linux. If $HOME environment variable was not set, Bazel would
crash with a std::logic_error. Using getpwuid() make Bazel more
resilient to wrong environment.

--
MOS_MIGRATED_REVID=89292008

1 files changed, 12 insertions, 1 deletions

diff --git a/src/main/cpp/blaze_util_linux.cc b/src/main/cpp/blaze_util_linux.cc
index c5c32daafc..1ccfd232ce 100644
--- a/src/main/cpp/blaze_util_linux.cc
+++ b/src/main/cpp/blaze_util_linux.cc
@@ -16,6 +16,8 @@
 #include <string.h>  // strerror
 #include <sys/statfs.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <pwd.h>
 
 #include "blaze_exit_code.h"
 #include "blaze_util_platform.h"
@@ -28,7 +30,16 @@ namespace blaze {
 using std::string;
 
 string GetOutputRoot() {
-  return blaze_util::JoinPath(getenv("HOME"), ".cache/bazel");
+  char buf[2048];
+  struct passwd pwbuf;
+  struct passwd *pw = NULL;
+  int uid = getuid();
+  int r = getpwuid_r(uid, &pwbuf, buf, 2048, &pw);
+  if (r != -1 && pw != NULL) {
+    return blaze_util::JoinPath(pw->pw_dir, ".cache/bazel");
+  } else {
+    return "/tmp";
+  }
 }
 
 void WarnFilesystemType(const string& output_base) {