google-ipmi-sys: initial commit: OEM IPMI handler

This implements a set of OEM IPMI commands built as sub-commands under
one OEM IPMI command registered in the Google OEM Namespace.

Change-Id: I65ff6f35838b501ac6ac67f7765bbc474b808660
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/psu.cpp b/psu.cpp
new file mode 100644
index 0000000..1a4d556
--- /dev/null
+++ b/psu.cpp
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "psu.hpp"
+
+#include "main.hpp"
+
+#include <cstdint>
+#include <fstream>
+#include <phosphor-logging/log.hpp>
+#include <sdbusplus/bus.hpp>
+
+namespace google
+{
+namespace ipmi
+{
+
+using namespace phosphor::logging;
+
+struct PsuResetRequest
+{
+    uint8_t subcommand;
+    // Delay in seconds.
+    uint32_t delay;
+} __attribute__((packed));
+
+static constexpr auto TIME_DELAY_FILENAME = "/run/psu_timedelay";
+static constexpr auto SYSTEMD_SERVICE = "org.freedesktop.systemd1";
+static constexpr auto SYSTEMD_ROOT = "/org/freedesktop/systemd1";
+static constexpr auto SYSTEMD_INTERFACE = "org.freedesktop.systemd1.Manager";
+static constexpr auto PSU_HARDRESET_TARGET = "gbmc-psu-hardreset.target";
+
+ipmi_ret_t PsuHardReset(const uint8_t* reqBuf, uint8_t* replyBuf,
+                        size_t* dataLen)
+{
+    if ((*dataLen) < sizeof(struct PsuResetRequest))
+    {
+        fprintf(stderr, "Invalid command length: %lu\n", (*dataLen));
+        return IPMI_CC_INVALID;
+    }
+
+    struct PsuResetRequest request;
+    memcpy(&request, &reqBuf[0], sizeof(struct PsuResetRequest));
+
+    std::ofstream ofs;
+    ofs.open(TIME_DELAY_FILENAME, std::ofstream::out);
+    if (!ofs.good())
+    {
+        fprintf(stderr, "Unable to open file for output.\n");
+        return IPMI_CC_INVALID;
+    }
+
+    ofs << "PSU_HARDRESET_DELAY=" << request.delay << std::endl;
+    if (ofs.fail())
+    {
+        fprintf(stderr, "Write failed\n");
+        ofs.close();
+        return IPMI_CC_INVALID;
+    }
+
+    // Write succeeded, please continue.
+    ofs.flush();
+    ofs.close();
+
+    auto bus = sdbusplus::bus::new_default();
+    auto method = bus.new_method_call(SYSTEMD_SERVICE, SYSTEMD_ROOT,
+                                      SYSTEMD_INTERFACE, "StartUnit");
+
+    method.append(PSU_HARDRESET_TARGET);
+    method.append("replace");
+
+    try
+    {
+        bus.call_noreply(method);
+    }
+    catch (const sdbusplus::exception::SdBusError& ex)
+    {
+        log<level::ERR>("Failed to call PSU hard reset");
+        return IPMI_CC_INVALID;
+    }
+
+    replyBuf[0] = SysPsuHardReset;
+    (*dataLen) = sizeof(uint8_t);
+
+    return IPMI_CC_OK;
+}
+
+} // namespace ipmi
+} // namespace google