Clean entire arg block when setting process name.

When Android processes fork from Zygote, we rewrite the command line
with a new name, eg. "system_server".  When we do this, we should
fill the entire block with zeros to remove corrupted argument
information that may otherwise remain in the /proc/<pid>/cmdline buffer
and be seen in tools and stack dumps.

Fixed an issue where VM options could be overwritten after setting
the nice name if the name was too long.

Bug: 17474152
Change-Id: Ie6cf9ed7752a04300a340e26cd6812bb35c59e1b

1 files changed, 1 insertions, 22 deletions

diff --git a/core/jni/AndroidRuntime.cpp b/core/jni/AndroidRuntime.cpp
index a63258c..1573106 100644
--- a/core/jni/AndroidRuntime.cpp
+++ b/core/jni/AndroidRuntime.cpp
@@ -271,6 +271,7 @@ AndroidRuntime::~AndroidRuntime()
 }
 
 void AndroidRuntime::setArgv0(const char* argv0) {
+    memset(mArgBlockStart, 0, mArgBlockLength);
     strlcpy(mArgBlockStart, argv0, mArgBlockLength);
 }
 
@@ -345,28 +346,6 @@ static bool runtime_isSensitiveThread() {
     return state && state->getStrictModePolicy() != 0;
 }
 
-
-/**
- * Add VM arguments to the to-be-executed VM
- * Stops at first non '-' argument (also stops at an argument of '--')
- * Returns the number of args consumed
- */
-int AndroidRuntime::addVmArguments(int argc, const char* const argv[])
-{
-    int i;
-
-    for (i = 0; i<argc; i++) {
-        if (argv[i][0] != '-') {
-            return i;
-        }
-        if (argv[i][1] == '-' && argv[i][2] == 0) {
-            return i+1;
-        }
-        addOption(argv[i]);
-    }
-    return i;
-}
-
 static int hasDir(const char* dir)
 {
     struct stat s;