[libFuzzer] Don't prefix absolute paths in fuchsia.
The ExecuteCommand function in fuchsia used to prefix the
getOutputFile for each command run with the artifact_prefix flag if
it was available, because fuchsia components don't have a writable working
directory. However, if a file with a global path is provided, fuchsia
should honor that.
An example of this is using the global /tmp directory to store stuff.
In fuchsia it ended up being translated to data///tmp, whereas we want
to make sure it is using /tmp (which is available to components using the
isolated-temp feature).
To test this I made the change, compiled fuchsia with this toolchain and
ran a fuzzer with the -fork=1 flag (that mode makes use of the /tmp
directory). I also tested that normal fuzzing workflow was not affected
by this.
Author: charco (Marco Vanotti)
Differential Revision: https://reviews.llvm.org/D68774
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@374612 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/fuzzer/FuzzerUtilFuchsia.cpp b/lib/fuzzer/FuzzerUtilFuchsia.cpp
index 50071a7..79fd950 100644
--- a/lib/fuzzer/FuzzerUtilFuchsia.cpp
+++ b/lib/fuzzer/FuzzerUtilFuchsia.cpp
@@ -407,13 +407,14 @@
// that lacks a mutable working directory. Fortunately, when this is the case
// a mutable output directory must be specified using "-artifact_prefix=...",
// so write the log file(s) there.
+ // However, we don't want to apply this logic for absolute paths.
int FdOut = STDOUT_FILENO;
if (Cmd.hasOutputFile()) {
- std::string Path;
- if (Cmd.hasFlag("artifact_prefix"))
- Path = Cmd.getFlagValue("artifact_prefix") + "/" + Cmd.getOutputFile();
- else
- Path = Cmd.getOutputFile();
+ std::string Path = Cmd.getOutputFile();
+ bool IsAbsolutePath = Path.length() > 1 && Path[0] == '/';
+ if (!IsAbsolutePath && Cmd.hasFlag("artifact_prefix"))
+ Path = Cmd.getFlagValue("artifact_prefix") + "/" + Path;
+
FdOut = open(Path.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0);
if (FdOut == -1) {
Printf("libFuzzer: failed to open %s: %s\n", Path.c_str(),
