DBus在Hi3515中的移植

1.基础环境：

虚拟机：VMware Workstation8  操作系统：Ubuntu12.04  

交叉编译工具 arm-hismall-linux

以下为需要安装的库：

DBus版本：1.6.4    glib版本：2.32.4    libxml2版本：2.6.8   gettext版本：0.18

其中glib与gettext直接运行./configuire、make、make install进行安装

DBus需要libxml2动态链接库的支持，所以libxml2需要交叉编译 ./configure --host=arm-hismall-linux 、make、 make install 来安装

可能遇见的问题：

configure error: you must have either have gettext support in your C library, or use the***

编译glib时，先安装好gettext，遇到上述问题，运行ldconfig

2.交叉编译DBus

2.1 执行configure

./configure --host=arm-hismall-linux --with-xml=libxml （使用libxml解析器，如不用--with会遇到 expand.h:No such file or directory）

可能遇到的问题：

encoding.h:28:19: iconv.h: No such file or director

此种情况为glibxml2的版本太低。

libxml2.so: could not read symbols: File in wrong format

需要交叉编译libxml2库，并安装

checking for libxml-2.0 >= 2.6.0... configure: error: Explicitly requested libxml but libxml not found

其实已经安装上 libxml2 了的，这里只是一个环境变量没有设置好而已。
解决办法：

echo $PKG_CONFIG_PATH
(1)确定 /usr/local/libxml2/lib/pkgconfig 目录下有 libxml-2.0.pc
(2)export PKG_CONFIG_PATH=/usr/local/libxml2/lib/pkgconfig:$PKG_CONFIG_PATH
(3)再./configure一次，到没有出现错误就OK了。

2.2 执行make

可能遇到问题：

arm-hisi-linux/bin/ld: cannot find -lz

缺少libz库 sudo apt-get install lib64z1-dev

bus.c:694: undefined reference to `bus_set_watched_dirs'

缺少函数bus_set_watched_dirs的定义，具体可见  https://bugs.freedesktop.org/show_bug.cgi?id=33001

修改bus-1.6.4/bus/dir-watch-dnotify.c  如下为部分代码  （//add为添加部分）

#include <dbus/dbus-internals.h>
#include <dbus/dbus-list.h>
#include "dir-watch.h"     //add 
 
#define MAX_DIRS_TO_WATCH 128

/* use a static array to avoid handling OOM */
static int fds[MAX_DIRS_TO_WATCH];
static int num_fds = 0;
void bus_watch_directory(const char *dir, BusContext *context);    //add
//add function
void bus_set_watched_dirs(BusContext *context,DBusList **directories)
{
   DBusList *link=_dbus_list_get_first_link(directories);
   while(link!=NULL)
   {
     bus_watch_directory(link->data,context);
     link=_dbus_list_get_next_link(directories,link);
   }
}

修改bus-1.6.4/bus/bus.c  添加头文件

#include "dir-watch.h"

2.3 sudo make install

3. 运行dbus-daemon

以上执行完成后，可以在bus-1.6.4/bus/目录下找到dbus-daemon，即为交叉编译后的dbus应用；bus-1.6.4/tools/目录下找到dbus-launch，为启动并配置dbus-daemon的程序，编写脚本dbus_run来启动dbus-launch

#!/bin/sh
if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then
## if not found, launch a new one
eval `dbus-launch --sh-syntax --exit-with-session`
echo "D-Bus per-session daemon address is: $DBUS_SESSION_BUS_ADDRESS"
fi

将dbus-daemon、dbus-launch放到开发板上/usr/bin/目录下 将libxml2.so.2 放到/usr/lib/ 下

在开发板上运行dbus-daemon进行测试

可能遇到的问题：

# dbus-daemon --system

Failed to start message bus: Failed to open "/usr/local/etc/dbus-1/system.conf":
No such file or directory

于是我又到dbus-1.6.4/bus中找到system.conf  session.conf(针对--session参数)

# dbus-daemon --system

Failed to start message bus: Failed to open ：".....system.d" No such file or directory

于是响应目录下建了个system.d文件夹 （创建session.d 针对--session参数）

# dbus-daemon --system

Failed to start message bus: Failed to bind socket "/var/run/dbus/system_bus_soc ket

No such file or directory

在相应目录下创建system_bus_socket，结果

# dbus-daemon --system

Failed to start message bus: Failed to bind socket "/var/run/dbus/system_bus_soc ket：Address already in use

郁闷，删掉system_bus_socket，只留/var/run/dbus/

# dbus-daemon --system

Failed to start message bus:Could not get UID and GID for username "messagebus"

通过添加用户解决 adduser messagebus 密码设为dbus 也可以在/etc/passwd后添加 

messagebus:$1$$YwM2vWXS3L4EbCfJU4I7N0:500:500:Linux User,,,:/home/messagebus:/bi   //为adduser messagebus命令生成

到这一步dbus-daemon可正常运行

4.编写应用测试DBus

4.1 gcc编译

在网上找了一段代码，感觉还不错 代码贴出如下 引用地址：http://hi.baidu.com/zengzhaonong/item/5143e33eb880abfedf222173

/*
* Example low-level D-Bus code.
* Written by Matthew Johnson <dbus@matthew.ath.cx>
*
* This code has been released into the Public Domain.
* You may do whatever you like with it.
*/
#include <dbus/dbus.h>
#include <stdbool.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

/**
* Connect to the DBUS bus and send a broadcast signal
*/
void sendsignal(char* sigvalue)
{
   DBusMessage* msg;
   DBusMessageIter args;
   DBusConnection* conn;
   DBusError err;
   int ret;
   dbus_uint32_t serial = 0;

   printf("Sending signal with value %s\n", sigvalue);

   // initialise the error value
   dbus_error_init(&err);

   // connect to the DBUS system bus, and check for errors
   conn = dbus_bus_get(DBUS_BUS_SESSION, &err);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Connection Error (%s)\n", err.message);
      dbus_error_free(&err);
   }
   if (NULL == conn) {
      exit(1);
   }

   // register our name on the bus, and check for errors
   ret = dbus_bus_request_name(conn, "test.signal.source", DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Name Error (%s)\n", err.message);
      dbus_error_free(&err);
   }
   if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {
      exit(1);
   }

   // create a signal & check for errors
   msg = dbus_message_new_signal("/test/signal/Object", // object name of the signal
                                 "test.signal.Type",    // interface name of the signal
                                 "Test");               // name of the signal
   if (NULL == msg)
   {
      fprintf(stderr, "Message Null\n");
      exit(1);
   }

   // append arguments onto signal
   dbus_message_iter_init_append(msg, &args);
   if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, &sigvalue)) {
      fprintf(stderr, "Out Of Memory!\n");
      exit(1);
   }

   // send the message and flush the connection
   if (!dbus_connection_send(conn, msg, &serial)) {
      fprintf(stderr, "Out Of Memory!\n");
      exit(1);
   }
   dbus_connection_flush(conn);
  
   printf("Signal Sent\n");
  
   // free the message
   dbus_message_unref(msg);
}

/**
* Call a method on a remote object
*/
void query(char* param)
{
   DBusMessage* msg;
   DBusMessageIter args;
   DBusConnection* conn;
   DBusError err;
   DBusPendingCall* pending;
   int ret;
   bool stat;
   dbus_uint32_t level;

   printf("Calling remote method with %s\n", param);

   // initialiset the errors
   dbus_error_init(&err);

   // connect to the system bus and check for errors
   conn = dbus_bus_get(DBUS_BUS_SESSION, &err);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Connection Error (%s)\n", err.message);
      dbus_error_free(&err);
   }
   if (NULL == conn) {
      exit(1);
   }

   // request our name on the bus
   ret = dbus_bus_request_name(conn, "test.method.caller", DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Name Error (%s)\n", err.message);
      dbus_error_free(&err);
   }
   if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {
      exit(1);
   }

   // create a new method call and check for errors
   msg = dbus_message_new_method_call("test.method.server",// target for the method call
                                      "/test/method/Object", // object to call on
                                      "test.method.Type",    // interface to call on
                                      "Method");             // method name
   if (NULL == msg) {
      fprintf(stderr, "Message Null\n");
      exit(1);
   }

   // append arguments
   dbus_message_iter_init_append(msg, &args);
   if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, &param)) {
      fprintf(stderr, "Out Of Memory!\n");
      exit(1);
   }
  
   // send message and get a handle for a reply
   if (!dbus_connection_send_with_reply (conn, msg, &pending, -1)) { // -1 is default timeout
      fprintf(stderr, "Out Of Memory!\n");
      exit(1);
   }
   if (NULL == pending) {
      fprintf(stderr, "Pending Call Null\n");
      exit(1);
   }
   dbus_connection_flush(conn);
  
   printf("Request Sent\n");
  
   // free message
   dbus_message_unref(msg);
  
   // block until we recieve a reply
   dbus_pending_call_block(pending);

   // get the reply message
   msg = dbus_pending_call_steal_reply(pending);
   if (NULL == msg) {
      fprintf(stderr, "Reply Null\n");
      exit(1);
   }
   // free the pending message handle
   dbus_pending_call_unref(pending);

   // read the parameters
   if (!dbus_message_iter_init(msg, &args))
      fprintf(stderr, "Message has no arguments!\n");
   else if (DBUS_TYPE_BOOLEAN != dbus_message_iter_get_arg_type(&args))
      fprintf(stderr, "Argument is not boolean!\n");
   else
      dbus_message_iter_get_basic(&args, &stat);

   if (!dbus_message_iter_next(&args))
      fprintf(stderr, "Message has too few arguments!\n");
   else if (DBUS_TYPE_UINT32 != dbus_message_iter_get_arg_type(&args))
      fprintf(stderr, "Argument is not int!\n");
   else
      dbus_message_iter_get_basic(&args, &level);

   printf("Got Reply: %d, %d\n", stat, level);
  
   // free reply
   dbus_message_unref(msg);  
}


void reply_to_method_call(DBusMessage* msg, DBusConnection* conn)
{
   DBusMessage* reply;
   DBusMessageIter args;
   bool stat = true;
   dbus_uint32_t level = 21614;
   dbus_uint32_t serial = 0;
   char* param = "";

   // read the arguments
   if (!dbus_message_iter_init(msg, &args))
      fprintf(stderr, "Message has no arguments!\n");
   else if (DBUS_TYPE_STRING != dbus_message_iter_get_arg_type(&args))
      fprintf(stderr, "Argument is not string!\n");
   else
      dbus_message_iter_get_basic(&args, &param);

   printf("Method called with %s\n", param);

   // create a reply from the message
   reply = dbus_message_new_method_return(msg);

   // add the arguments to the reply
   dbus_message_iter_init_append(reply, &args);
   if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_BOOLEAN, &stat)) {
      fprintf(stderr, "Out Of Memory!\n");
      exit(1);
   }
   if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_UINT32, &level)) {
      fprintf(stderr, "Out Of Memory!\n");
      exit(1);
   }

   // send the reply && flush the connection
   if (!dbus_connection_send(conn, reply, &serial)) {
      fprintf(stderr, "Out Of Memory!\n");
      exit(1);
   }
   dbus_connection_flush(conn);

   // free the reply
   dbus_message_unref(reply);
}



/**
* Server that exposes a method call and waits for it to be called
*/
void listen()
{
   DBusMessage* msg;
   DBusMessage* reply;
   DBusMessageIter args;
   DBusConnection* conn;
   DBusError err;
   int ret;
   char* param;

   printf("Listening for method calls\n");

   // initialise the error
   dbus_error_init(&err);
  
   // connect to the bus and check for errors
   conn = dbus_bus_get(DBUS_BUS_SESSION, &err);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Connection Error (%s)\n", err.message);
      dbus_error_free(&err);
   }
   if (NULL == conn) {
      fprintf(stderr, "Connection Null\n");
      exit(1);
   }
  
   // request our name on the bus and check for errors
   ret = dbus_bus_request_name(conn, "test.method.server",
                               DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Name Error (%s)\n", err.message);
      dbus_error_free(&err);
   }
   if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {
      fprintf(stderr, "Not Primary Owner (%d)\n", ret);
      exit(1);
   }

   // loop, testing for new messages
   while (true) {
      // non blocking read of the next available message
      dbus_connection_read_write(conn, 0);
      msg = dbus_connection_pop_message(conn);

      // loop again if we haven't got a message
      if (NULL == msg) {
         sleep(1);
         continue;
      }
     
      // check this is a method call for the right interface & method
      if (dbus_message_is_method_call(msg, "test.method.Type", "Method"))
         reply_to_method_call(msg, conn);

      // free the message
      dbus_message_unref(msg);
   }
}



/**
* Listens for signals on the bus
*/
void receive()
{
   DBusMessage* msg;
   DBusMessageIter args;
   DBusConnection* conn;
   DBusError err;
   int ret;
   char* sigvalue;

   printf("Listening for signals\n");

   // initialise the errors
   dbus_error_init(&err);
  
   // connect to the bus and check for errors
   conn = dbus_bus_get(DBUS_BUS_SESSION, &err);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Connection Error (%s)\n", err.message);
      dbus_error_free(&err);
   }
   if (NULL == conn) {
      exit(1);
   }
  
   // request our name on the bus and check for errors
   ret = dbus_bus_request_name(conn, "test.signal.sink", DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Name Error (%s)\n", err.message);
      dbus_error_free(&err);
   }
   if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {
      exit(1);
   }

   // add a rule for which messages we want to see
   dbus_bus_add_match(conn, "type='signal',interface='test.signal.Type'", &err); // see signals from the given interface
   dbus_connection_flush(conn);
   if (dbus_error_is_set(&err)) {
      fprintf(stderr, "Match Error (%s)\n", err.message);
      exit(1);
   }
   printf("Match rule sent\n");

   // loop listening for signals being emmitted
   while (true) {

      // non blocking read of the next available message
      dbus_connection_read_write(conn, 0);
      msg = dbus_connection_pop_message(conn);

      // loop again if we haven't read a message
      if (NULL == msg) {
         sleep(1);
         continue;
      }

      // check if the message is a signal from the correct interface and with the correct name
      if (dbus_message_is_signal(msg, "test.signal.Type", "Test")) {
        
         // read the parameters
         if (!dbus_message_iter_init(msg, &args))
            fprintf(stderr, "Message Has No Parameters\n");
         else if (DBUS_TYPE_STRING != dbus_message_iter_get_arg_type(&args))
            fprintf(stderr, "Argument is not string!\n");
         else
            dbus_message_iter_get_basic(&args, &sigvalue);
        
         printf("Got Signal with value %s\n", sigvalue);
      }

      // free the message
      dbus_message_unref(msg);
   }
}



int main(int argc, char** argv)
{
   if (2 > argc) {
      printf ("Syntax: dbus-example [send|receive|listen|query] [<param>]\n");
      return 1;
   }
   char* param = "no param";
   if (3 >= argc && NULL != argv[2]) param = argv[2];
   if (0 == strcmp(argv[1], "send"))
      sendsignal(param);
   else if (0 == strcmp(argv[1], "receive"))
      receive();
   else if (0 == strcmp(argv[1], "listen"))
      listen();
   else if (0 == strcmp(argv[1], "query"))
      query(param);
   else {
      printf ("Syntax: dbus-example [send|receive|listen|query] [<param>]\n");
      return 1;
   }
   return 0;
} 

gcc编译问题：

错误1:
$ gcc test.c
test.c:8:23: 错误： dbus/dbus.h：No such file or directory
......
$
错误提示，dbus库的头文件位置不正确(如果已经安装了dbus的话)
$ sudo updatedb
$ sudo locate dbus.h (查看dbus.h的所在位置)
/usr/local/include/dbus-1.0/dbus/dbus.h
/usr/include/dbus-1.0/dbus/dbus.h
看来dbus.h的存放位置的确不正确，这可能是由于dbus-1.0的安装位置有问题，没关系，调整一下dbus的头文件位置就可以了(调整方法如下):
root@zxl:/usr/include# ln -sf dbus-1.0/dbus


错误2:
$ gcc test.c
在包含自 test.c：8 的文件中:
/usr/include/dbus/dbus.h:29:33: 错误： dbus/dbus-arch-deps.h：No such file or directory
......

依然有头文件无法正确定位的问题，从错误提示来看，该文件应该在/usr/include/dbus/目录下，可是进入该目录查看竟然没有，那就在整个系统中查找该文件。
root@zxl:/usr/include/dbus# locate dbus-arch-deps.h
/usr/local/lib/dbus-1.0/include/dbus/dbus-arch-deps.h
/usr/lib/dbus-1.0/include/dbus/dbus-arch-deps.h
将该文件复制到/usr/include/dbus目录下


错误3:
$ gcc test.c
......
test.c:(.text+0xbb6): undefined reference to `dbus_message_iter_get_basic'
test.c:(.text+0xbd4): undefined reference to `dbus_message_unref'
collect2: ld 返回 1

需要连接动态库dbus
$ cd /usr/lib
$ ls *dbus*
libdbus-1.a   libdbus-1.so.3      libdbus-glib-1.so
libdbus-1.la libdbus-1.so.3.2.0 libdbus-glib-1.so.2
libdbus-1.so libdbus-glib-1.a    libdbus-glib-1.so.2.1.0

$ gcc test.c -l dbus-1 -o dbus

gcc执行：

$ ./dbus receive
Listening for signals
Match rule sent
Got Signal with value doctorQBW　　

$ ./dbus send doctorQBW    (再开一个标签)
Sending signal with value doctorQBW
Signal Sent

4.2 交叉编译

交叉编译过程如下：

将该文件命名dbustest.c

$ arm-hismall-linux-gcc send.c

会出现 error:dbus/dbus.h：No such file or directory 即使gcc可以编译而且 dbus/dbus.h就在/usr/include中 也找不到dbus/dbus.h，没办法把bus-1.6.4/dbus目录拷贝到dbustest当前目录，

将dbustest中的 #include <dbus/dbus.h> 改为 #include "dbus/dbus.h"

将dbus.h中的 #include <dbus/xxx.h> 都改为 #include "dbus/xxx.h" 

将bus-1.6.4/dbus/.libs/libdbus-1.so拷贝到 dbustest当前目录

$ arm-hismall-linux-gcc dbustest.c -o dbustest -I./ -L ./ -ldbus-1

即可编译通过

ps:不知道怎么让交叉编译工具通过#include <dbus/xxx.h> 找到/usr/include/dbus下的头文件，若知道请留言指教

4.3 dbustest测试

将bus-1.6.4/dbus/.libs/libdbus-1.so.3拷贝到开发板/usr/lib/

在已经运行dbus-daemon进程的开发板上执行dbustest(命令同gcc测试处)

可能出现的问题：

Connection Error (Using X11 for dbus-daemon autolaunch was disabled at compile time, set your DBUS_SESSION_BUS_ADDRESS instead)

需要设置DBUS_SESSION_BUS_ADDRESS，在执行脚本dbus_run时，会显示

D-Bus per-session daemon address is: unix:path=/tmp/dbus-pebh4YY2Pp,guid=3ab7577588cdf4e7773663ae38792d8d

 设置环境变量： 

export DBUS_SESSION_BUS_ADDRESS=‘unix:path=/tmp/dbus-pebh4YY2Pp’

到此可正常运行dbustest。

 如有错误请指出，如果引用请注明出处： http://www.cnblogs.com/doctorqbw/archive/2012/08/23/2652785.html