ipc_pipe.c File Reference

#include "ipc_pipe.h"
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

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Macros
#define	IPC_MAX_BUFFER   4096

Functions
int	ipc_pipe_send (struct ipc_pipe_context *context, const char *msg, int len)
	sends given msg via the given context. Do not use this method directly, use ipc_send of ipc.h instead.
char *	ipc_pipe_retrieve (struct ipc_pipe_context *context)
	retrieves message from the given context. Do not use this method directly, use ipc_retrieve of ipc.h instead.
int	ipc_pipe_close (struct ipc_pipe_context *context)
	closes given context. Do not use this method directly, use ipc_close of ipc.h instead.
int	ipc_pipe_destroy (struct ipc_pipe_context *context)
	destroys given context. Do not use this method directly, use ipc_destroy of ipc.h instead.
struct ipc_pipe_context *	ipc_init_pipe (void)
	initializes a new context. Do not use this method directly, use ipc_init of ipc.h instead.

Macro Definition Documentation

IPC_MAX_BUFFER

#define IPC_MAX_BUFFER   4096

Definition at line 17 of file ipc_pipe.c.

Referenced by ipc_pipe_retrieve().

Function Documentation

ipc_init_pipe()

struct ipc_pipe_context * ipc_init_pipe

(

void

)

initializes a new context. Do not use this method directly, use ipc_init of ipc.h instead.

Returns

a heap allocated ipc_pipe_context or NULL on failure.

Definition at line 132 of file ipc_pipe.c.

{
  struct ipc_pipe_context *pc = NULL;
  if ((pc = calloc (1, sizeof (*pc))) == NULL)
    goto error;
  if (pipe (pc->fd) == -1)
    {
      goto error;
    }
  return pc;
error:
  if (pc != NULL)
    free (pc);
  return NULL;
}

References ipc_pipe_context::fd, and free().

Referenced by ipc_init().

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ipc_pipe_close()

int ipc_pipe_close

(

struct ipc_pipe_context *

context

)

closes given context. Do not use this method directly, use ipc_close of ipc.h instead.

Parameters

context

the ipc_pipe_context to be closed.

Returns

0 on success, -1 on failure.

Definition at line 85 of file ipc_pipe.c.

{
  int rc = 0;
  if (context == NULL)
    {
      rc = -1;
      goto exit;
    }
  if ((rc = close (context->fd[0])) < 0)
    goto exit;
  if ((rc = close (context->fd[1])) < 0)
    goto exit;
exit:
  return rc;
}

References ipc_pipe_context::fd.

Referenced by ipc_close(), and ipc_pipe_destroy().

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ipc_pipe_destroy()

int ipc_pipe_destroy

(

struct ipc_pipe_context *

context

)

destroys given context. Do not use this method directly, use ipc_destroy of ipc.h instead.

Parameters

context

the ipc_pipe_context to be destroyed.

Returns

0 on success, -1 on failure.

Definition at line 110 of file ipc_pipe.c.

{
  int rc = 0;
  if (context == NULL)
    {
      rc = -1;
      goto exit;
    }
  if ((rc = ipc_pipe_close (context)) < 0)
    goto exit;
  free (context);
exit:
  return rc;
}

References free(), and ipc_pipe_close().

Referenced by ipc_destroy().

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ipc_pipe_retrieve()

char * ipc_pipe_retrieve

(

struct ipc_pipe_context *

context

)

retrieves message from the given context. Do not use this method directly, use ipc_retrieve of ipc.h instead.

Parameters

context

the ipc_pipe_context to be used; must be previously initialized via ipc_pipe_init.

Returns

a heap allocated char array or NULL on failure.

Definition at line 50 of file ipc_pipe.c.

{
  char *result = NULL;
  int rfd, pf;
  rfd = context->fd[0];
  pf = fcntl (rfd, F_GETFL, 0);
  if (pf < 0 && errno != EBADF)
    // fd is closed or invalid; we assume closed
    return NULL;
  fcntl (rfd, F_SETFL, pf | O_NONBLOCK);
  if ((result = calloc (1, IPC_MAX_BUFFER)) == NULL)
    return NULL;
 
  if (read (rfd, result, IPC_MAX_BUFFER) > 0)
    {
      return result;
    }
  else
    {
      free (result);
      // if temporary unavailable or not a closed descriptor don't
      // print an error.
      return NULL;
    }
}

References ipc_pipe_context::fd, free(), and IPC_MAX_BUFFER.

Referenced by ipc_retrieve().

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ipc_pipe_send()

int ipc_pipe_send	(	struct ipc_pipe_context *	context,
		const char *	msg,
		int	len )

sends given msg via the given context. Do not use this method directly, use ipc_send of ipc.h instead.

Parameters

context	the ipc_pipe_context to be used; must be previously initialized via ipc_pipe_init.
msg	the message to send
len	the length of msg

Returns

bytes written, 1 on write error

Definition at line 32 of file ipc_pipe.c.

{
  int wfd, wr;
  wfd = context->fd[1];
  wr = write (wfd, msg, len);
  return wr;
}

References ipc_pipe_context::fd, and len.

Referenced by ipc_send().

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