apphandler: Implement Get/Set System Info Parameter

Implement Get System Info Parameter using the parameter storage code to
back the string-type parameters. Supports up to 255 chunks (known as
"sets" in the spec) for those parameters. Currently, iterated reads by
chunk of a string parameter will repeatedly invoke that parameter's
callback, which can result in chunks being incoherent with each other if
the string changes between invocations. This is noted in a TODO comment.

Stub out Set System Info Parameter. Full implementation for that is
pending support for read-only flags in the parameter storage code.

Change-Id: If0a9d807725ccf1f1f62e931010024841575469c
Signed-off-by: Xo Wang <xow@google.com>
Signed-off-by: Patrick Venture <venture@google.com>

3 files changed, 193 insertions, 8 deletions

diff --git a/apphandler.cpp b/apphandler.cpp
index 3abac14..7f16b1f 100644
--- a/apphandler.cpp
+++ b/apphandler.cpp
@@ -1,5 +1,14 @@
 #include "apphandler.h"
 
+#include "app/channel.hpp"
+#include "app/watchdog.hpp"
+#include "ipmid.hpp"
+#include "nlohmann/json.hpp"
+#include "sys_info_param.hpp"
+#include "transporthandler.hpp"
+#include "types.hpp"
+#include "utils.hpp"
+
 #include <arpa/inet.h>
 #include <mapper.h>
 #include <stdint.h>
@@ -21,20 +30,15 @@ namespace filesystem = std::experimental::filesystem;
 #error filesystem not available
 #endif
 
-#include "app/channel.hpp"
-#include "app/watchdog.hpp"
-#include "ipmid.hpp"
-#include "nlohmann/json.hpp"
-#include "transporthandler.hpp"
-#include "types.hpp"
-#include "utils.hpp"
-
+#include <algorithm>
 #include <array>
 #include <cstddef>
 #include <fstream>
+#include <memory>
 #include <phosphor-logging/elog-errors.hpp>
 #include <phosphor-logging/log.hpp>
 #include <string>
+#include <tuple>
 #include <vector>
 #include <xyz/openbmc_project/Common/error.hpp>
 #include <xyz/openbmc_project/Software/Activation/server.hpp>
@@ -629,6 +633,166 @@ ipmi_ret_t ipmi_app_get_sys_guid(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
     return rc;
 }
 
+static std::unique_ptr<SysInfoParamStore> sysInfoParamStore;
+
+struct IpmiSysInfoResp
+{
+    uint8_t paramRevision;
+    uint8_t setSelector;
+    union
+    {
+        struct
+        {
+            uint8_t encoding;
+            uint8_t stringLen;
+            uint8_t stringData0[14];
+        } __attribute__((packed));
+        uint8_t stringDataN[16];
+        uint8_t byteData;
+    };
+} __attribute__((packed));
+
+/**
+ * Split a string into (up to) 16-byte chunks as expected in response for get
+ * system info parameter.
+ *
+ * @param[in] fullString: Input string to be split
+ * @param[in] chunkIndex: Index of the chunk to be written out
+ * @param[in,out] chunk: Output data buffer; must have 14 byte capacity if
+ *          chunk_index = 0 and 16-byte capacity otherwise
+ * @return the number of bytes written into the output buffer, or -EINVAL for
+ * invalid arguments.
+ */
+static int splitStringParam(const std::string& fullString, int chunkIndex,
+                            uint8_t* chunk)
+{
+    constexpr int maxChunk = 255;
+    constexpr int smallChunk = 14;
+    constexpr int chunkSize = 16;
+    if (chunkIndex > maxChunk || chunk == nullptr)
+    {
+        return -EINVAL;
+    }
+    try
+    {
+        std::string output;
+        if (chunkIndex == 0)
+        {
+            // Output must have 14 byte capacity.
+            output = fullString.substr(0, smallChunk);
+        }
+        else
+        {
+            // Output must have 16 byte capacity.
+            output = fullString.substr((chunkIndex * chunkSize) - 2, chunkSize);
+        }
+
+        std::memcpy(chunk, output.c_str(), output.length());
+        return output.length();
+    }
+    catch (const std::out_of_range& e)
+    {
+        // The position was beyond the end.
+        return -EINVAL;
+    }
+}
+
+/**
+ * Packs the Get Sys Info Request Item into the response.
+ *
+ * @param[in] paramString - the parameter.
+ * @param[in] setSelector - the selector
+ * @param[in,out] resp - the System info response.
+ * @return The number of bytes packed or failure from splitStringParam().
+ */
+static int packGetSysInfoResp(const std::string& paramString,
+                              uint8_t setSelector, IpmiSysInfoResp* resp)
+{
+    uint8_t* dataBuffer = resp->stringDataN;
+    resp->setSelector = setSelector;
+    if (resp->setSelector == 0) // First chunk has only 14 bytes.
+    {
+        resp->encoding = 0;
+        resp->stringLen = paramString.length();
+        dataBuffer = resp->stringData0;
+    }
+    return splitStringParam(paramString, resp->setSelector, dataBuffer);
+}
+
+ipmi_ret_t ipmi_app_get_system_info(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
+                                    ipmi_request_t request,
+                                    ipmi_response_t response,
+                                    ipmi_data_len_t dataLen,
+                                    ipmi_context_t context)
+{
+    IpmiSysInfoResp resp = {};
+    size_t respLen = 0;
+    uint8_t* const reqData = static_cast<uint8_t*>(request);
+    std::string paramString;
+    bool found;
+    std::tuple<bool, std::string> ret;
+    constexpr int minRequestSize = 4;
+    constexpr int paramSelector = 1;
+    constexpr uint8_t revisionOnly = 0x80;
+    const uint8_t paramRequested = reqData[paramSelector];
+    int rc;
+
+    if (*dataLen < minRequestSize)
+    {
+        return IPMI_CC_REQ_DATA_LEN_INVALID;
+    }
+
+    *dataLen = 0; // default to 0.
+
+    // Parameters revision as of IPMI spec v2.0 rev. 1.1 (Feb 11, 2014 E6)
+    resp.paramRevision = 0x11;
+    if (reqData[0] & revisionOnly) // Get parameter revision only
+    {
+        respLen = 1;
+        goto writeResponse;
+    }
+
+    // The "Set In Progress" parameter can be used for rollback of parameter
+    // data and is not implemented.
+    if (paramRequested == 0)
+    {
+        resp.byteData = 0;
+        respLen = 2;
+        goto writeResponse;
+    }
+
+    if (sysInfoParamStore == nullptr)
+    {
+        sysInfoParamStore = std::make_unique<SysInfoParamStore>();
+    }
+
+    // Parameters other than Set In Progress are assumed to be strings.
+    ret = sysInfoParamStore->lookup(paramRequested);
+    found = std::get<0>(ret);
+    paramString = std::get<1>(ret);
+    if (!found)
+    {
+        return IPMI_CC_SYSTEM_INFO_PARAMETER_NOT_SUPPORTED;
+    }
+    // TODO: Cache each parameter across multiple calls, until the whole string
+    // has been read out. Otherwise, it's possible for a parameter to change
+    // between requests for its chunks, returning chunks incoherent with each
+    // other. For now, the parameter store is simply required to have only
+    // idempotent callbacks.
+    rc = packGetSysInfoResp(paramString, reqData[2], &resp);
+    if (rc == -EINVAL)
+    {
+        return IPMI_CC_RESPONSE_ERROR;
+    }
+
+    respLen = sizeof(resp); // Write entire string data chunk in response.
+
+writeResponse:
+    std::memcpy(response, &resp, sizeof(resp));
+    *dataLen = respLen;
+    return IPMI_CC_OK;
+}
+
 void register_netfn_app_functions()
 {
     // <Get BT Interface Capabilities>
@@ -686,5 +850,9 @@ void register_netfn_app_functions()
     // <Set Channel Access Command>
     ipmi_register_callback(NETFUN_APP, IPMI_CMD_SET_CHAN_ACCESS, NULL,
                            ipmi_set_channel_access, PRIVILEGE_ADMIN);
+
+    // <Get System Info Command>
+    ipmi_register_callback(NETFUN_APP, IPMI_CMD_GET_SYSTEM_INFO, NULL,
+                           ipmi_app_get_system_info, PRIVILEGE_USER);
     return;
 }
diff --git a/apphandler.h b/apphandler.h
index db2d07c..cbfafb2 100644
--- a/apphandler.h
+++ b/apphandler.h
@@ -20,6 +20,21 @@ enum ipmi_netfn_app_cmds
     IPMI_CMD_GET_CHANNEL_ACCESS = 0x41,
     IPMI_CMD_GET_CHAN_INFO = 0x42,
     IPMI_CMD_GET_CHAN_CIPHER_SUITES = 0x54,
+    IPMI_CMD_SET_SYSTEM_INFO = 0x58,
+    IPMI_CMD_GET_SYSTEM_INFO = 0x59,
+};
+
+enum ipmi_app_sysinfo_params
+{
+    IPMI_SYSINFO_SET_STATE = 0x00,
+    IPMI_SYSINFO_SYSTEM_FW_VERSION = 0x01,
+    IPMI_SYSINFO_SYSTEM_NAME = 0x02,
+    IPMI_SYSINFO_PRIMARY_OS_NAME = 0x03,
+    IPMI_SYSINFO_OS_NAME = 0x04,
+    IPMI_SYSINFO_OS_VERSION = 0x05,
+    IPMI_SYSINFO_BMC_URL = 0x06,
+    IPMI_SYSINFO_OS_HYP_URL = 0x07,
+    IPMI_SYSINFO_OEM_START = 0xC0, // Start of range of OEM parameters
 };
 
 #endif
diff --git a/host-ipmid/ipmid-api.h b/host-ipmid/ipmid-api.h
index a085270..820776a 100644
--- a/host-ipmid/ipmid-api.h
+++ b/host-ipmid/ipmid-api.h
@@ -114,6 +114,8 @@ enum ipmi_return_codes
     IPMI_CC_OK = 0x00,
     IPMI_DCMI_CC_NO_ACTIVE_POWER_LIMIT = 0x80,
     IPMI_WDOG_CC_NOT_INIT = 0x80,
+    IPMI_CC_SYSTEM_INFO_PARAMETER_NOT_SUPPORTED = 0x80,
+    IPMI_CC_SYSTEM_INFO_PARAMETER_SET_READ_ONLY = 0x82,
     IPMI_CC_BUSY = 0xC0,
     IPMI_CC_INVALID = 0xC1,
     IPMI_CC_INVALID_RESERVATION_ID = 0xC5,