[PATCH v2 10/15] scripts/oss-fuzz: Add wrapper program for generic fuzzer

[Alexander Bulekov]

On oss-fuzz we need some sort of wrapper to specify command-line
arguments or environment variables. When we had a similar problem with
other targets that I fixed with
05509c8e6d ("fuzz: select fuzz target using executable name")
by selecting the fuzz target based on the executable's name. In the
future should probably commit to one approach (wrapper binary or
argv0-based target selection).

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
---
 scripts/oss-fuzz/target.c | 40 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 scripts/oss-fuzz/target.c

diff --git a/scripts/oss-fuzz/target.c b/scripts/oss-fuzz/target.c
new file mode 100644
index 0000000000..4a7257412a
--- /dev/null
+++ b/scripts/oss-fuzz/target.c
@@ -0,0 +1,40 @@
+/*
+ * Copyright Red Hat Inc., 2020
+ *
+ * Authors:
+ *  Alexander Bulekov   <alxndr@bu.edu>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <libgen.h>
+#include <string.h>
+#include <unistd.h>
+
+
+/* Required for oss-fuzz to consider the binary a target. */
+static const char *magic __attribute__((used)) = "LLVMFuzzerTestOneInput";
+static const char args[] = {QEMU_FUZZ_ARGS, 0x00};
+static const char objects[] = {QEMU_FUZZ_OBJECTS, 0x00};
+
+int main(int argc, char *argv[])
+{
+    char path[PATH_MAX] = {0};
+    char *dir = dirname(argv[0]);
+    strncpy(path, dir, PATH_MAX);
+    strcat(path, "/deps/qemu-fuzz-i386-target-general-fuzz");
+
+    setenv("QEMU_FUZZ_ARGS", args, 0);
+    setenv("QEMU_FUZZ_OBJECTS", objects, 0);
+
+    argv[0] = path;
+    int ret = execvp(path, argv);
+    if (ret) {
+        perror("execv");
+    }
+    return ret;
+}
-- 
2.27.0