Introduce upoke function

This will be needed to implement fault injection on those architectures
that lack PTRACE_SETREGSET/PTRACE_SETREGS support.

* defs.h (upoke): New prototype.
* upoke.c: New file.
* Makefile.am (libstrace_a_SOURCES): Add it.

1 files changed, 40 insertions, 0 deletions

diff --git a/upoke.c b/upoke.c
new file mode 100644
index 000000000..e22c1eed9
--- /dev/null
+++ b/upoke.c
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "defs.h"
+#include "ptrace.h"
+
+int
+upoke(int pid, long off, long val)
+{
+	if (ptrace(PTRACE_POKEUSER, (pid_t) pid, (void *) off, (void *) val)) {
+		if (errno != ESRCH)
+			perror_msg("upoke: PTRACE_POKEUSER pid:%d @%#lx)", pid, off);
+		return -1;
+	}
+	return 0;
+}