ACE/examples/IPC_SAP/FIFO_SAP/FIFO-test.cpp

   1 // Purpose: This program uses ACE_FIFO wrappers to perform
   2 // interprocess communication between a parent process and a child
   3 // process.  The parents reads from an input file and writes it into
   4 // the fifo.  The child reads from the ACE_FIFO and executes the more
   5 // command.
   6
   7 #include "ace/FIFO_Recv.h"
   8 #include "ace/FIFO_Send.h"
   9 #include "ace/Log_Msg.h"
  10 #include "ace/OS_NS_sys_wait.h"
  11 #include "ace/OS_NS_unistd.h"
  12 #include "ace/OS_NS_stdlib.h"
  13 #include "ace/OS_NS_fcntl.h"
  14
  15 #define PERMS                   0666
  16 #define EXEC_NAME               "more"
  17 #define EXEC_COMMAND_ARG        "more"
  18
  19 static const ACE_TCHAR *FIFO_NAME = ACE_TEXT ("/tmp/fifo");
  20
  21 static int
  22 do_child (ACE_FIFO_Recv &fifo_reader)
  23 {
  24   // Set child's stdin to read from the fifo.
  25   if (ACE_OS::close (ACE_STDIN) == -1
  26       || ACE_OS::dup (fifo_reader.get_handle ()) == ACE_INVALID_HANDLE)
  27     return -1;
  28
  29   char *argv[2];
  30   argv[0] = const_cast<char *> (EXEC_COMMAND_ARG);
  31   argv[1] = 0;
  32
  33   if (ACE_OS::execvp (EXEC_NAME, argv) == -1)
  34     return -1;
  35   return 0;
  36 }
  37
  38 static int
  39 do_parent (const ACE_TCHAR fifo_name[],
  40            ACE_TCHAR input_filename[])
  41 {
  42   ACE_FIFO_Send fifo_sender (fifo_name, O_WRONLY | O_CREAT);
  43   ssize_t len;
  44   char buf[BUFSIZ];
  45
  46   if (fifo_sender.get_handle () == ACE_INVALID_HANDLE)
  47     return -1;
  48
  49   ACE_HANDLE inputfd =
  50     ACE_OS::open (input_filename, O_RDONLY);
  51
  52   if (inputfd == ACE_INVALID_HANDLE)
  53     return -1;
  54
  55   // Read from input file and write into input end of the fifo.
  56
  57   while ((len = ACE_OS::read (inputfd, buf, sizeof buf)) > 0)
  58     if (fifo_sender.send (buf, len) != len)
  59       return -1;
  60
  61   if (len == -1)
  62     return -1;
  63
  64   if (fifo_sender.remove () == -1)
  65     return -1;
  66   return 0;
  67 }
  68
  69 int
  70 ACE_TMAIN (int argc, ACE_TCHAR *argv[])
  71 {
  72   ACE_LOG_MSG->open (argv[0]);
  73
  74   if (argc != 2)
  75     {
  76       ACE_ERROR ((LM_ERROR,
  77                   ACE_TEXT ("usage: %n input-file\n"),
  78                   1));
  79       ACE_OS::exit (1);
  80     }
  81
  82   ACE_FIFO_Recv fifo_reader (FIFO_NAME, O_RDONLY | O_CREAT, PERMS, 0);
  83
  84   if (fifo_reader.get_handle () == ACE_INVALID_HANDLE)
  85     return -1;
  86
  87   pid_t const child_pid = ACE_OS::fork ();
  88
  89   switch (child_pid)
  90     {
  91     case -1:
  92       ACE_ERROR ((LM_ERROR,
  93                   ACE_TEXT ("%n: %p\n"),
  94                   ACE_TEXT ("fork"),
  95                   1));
  96       ACE_OS::abort ();
  97     case 0:
  98       if (do_child (fifo_reader) == -1)
  99         {
 100           ACE_ERROR ((LM_ERROR,
 101                       ACE_TEXT ("%n: %p\n"),
 102                       ACE_TEXT ("do_child"),
 103                       1));
 104           ACE_OS::abort ();
 105         }
 106       ACE_FALLTHROUGH;
 107     default:
 108       if (do_parent (FIFO_NAME, argv[1]) == -1)
 109         {
 110           ACE_ERROR ((LM_ERROR,
 111                       ACE_TEXT ("%n: %p\n"),
 112                       ACE_TEXT ("do_parent"),
 113                       1));
 114           ACE_OS::abort ();
 115         }
 116
 117       // wait for child to ACE_OS::exit.
 118       if (ACE_OS::waitpid (child_pid, (ACE_exitcode *) 0, 0) == -1)
 119         ACE_ERROR ((LM_ERROR,
 120                     ACE_TEXT ("%n: %p\n%a"),
 121                     ACE_TEXT ("waitpid"),
 122                     1));
 123     }
 124
 125   return 0;
 126 }