From 722f625af09df89a0e8d3b2a2a966e6fcf8b4f48 Mon Sep 17 00:00:00 2001
From: Guo Wenxue <guowenxue@gmail.com>
Date: Wed, 05 Dec 2018 23:01:17 +0800
Subject: [PATCH] Add IPC fifo sample code
---
ch6_ipc/fifo_chat.c | 148 +++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 148 insertions(+), 0 deletions(-)
diff --git a/ch6_ipc/fifo_chat.c b/ch6_ipc/fifo_chat.c
new file mode 100644
index 0000000..ec1c3c4
--- /dev/null
+++ b/ch6_ipc/fifo_chat.c
@@ -0,0 +1,148 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <libgen.h>
+#include <stdlib.h>
+
+#define FIFO_FILE1 ".fifo_chat1"
+#define FIFO_FILE2 ".fifo_chat2"
+
+int g_stop = 0;
+
+void sig_pipe(int signum)
+{
+ if(SIGPIPE == signum)
+ {
+ printf("get pipe broken signal and let programe exit\n");
+ g_stop = 1;
+ }
+}
+
+int main(int argc, char **argv)
+{
+ int fdr_fifo;
+ int fdw_fifo;
+ int rv;
+ fd_set rdset;
+ char buf[1024];
+ int mode = 0;
+ char *rd_fifo = NULL;
+ char *wr_fifo = NULL;
+
+ if( argc != 2 )
+ {
+ printf("Usage: %s [0/1]\n", basename(argv[0]));
+ printf("This chat program need run twice, 1st time run with [0] and 2nd time with [1]\n");
+ return -1;
+ }
+
+ mode = atoi(argv[1]);
+
+ if( 0 == mode )
+ {
+ rd_fifo = FIFO_FILE1;
+ wr_fifo = FIFO_FILE2;
+ }
+ else
+ {
+ rd_fifo = FIFO_FILE2;
+ wr_fifo = FIFO_FILE1;
+ }
+
+ if( access(FIFO_FILE1 , F_OK) )
+ {
+ printf("FIFO file \"%s\" not exist and create it now\n", FIFO_FILE1);
+ mkfifo(FIFO_FILE1, 0666);
+ }
+
+ if( access(FIFO_FILE2 , F_OK) )
+ {
+ printf("FIFO file \"%s\" not exist and create it now\n", FIFO_FILE2);
+ mkfifo(FIFO_FILE2, 0666);
+ }
+
+ signal(SIGPIPE, sig_pipe);
+
+ if( 0 == mode )
+ {
+ printf("start open '%s' for read and it will blocked untill write endpoint opened...\n", rd_fifo);
+ if( (fdr_fifo=open(rd_fifo, O_RDONLY)) < 0 )
+ {
+ printf("Open fifo[%s] for chat read endpoint failure: %s\n", rd_fifo, strerror(errno));
+ return -1;
+ }
+
+ printf("start open '%s' for write...\n", wr_fifo);
+ if( (fdw_fifo=open(wr_fifo, O_WRONLY)) < 0 )
+ {
+ printf("Open fifo[%s] for chat write endpoint failure: %s\n", wr_fifo, strerror(errno));
+ return -1;
+ }
+ }
+ else
+ {
+ printf("start open '%s' for write and it will blocked untill read endpoint opened...\n", wr_fifo);
+ if( (fdw_fifo=open(wr_fifo, O_WRONLY)) < 0 )
+ {
+ printf("Open fifo[%s] for chat write endpoint failure: %s\n", wr_fifo, strerror(errno));
+ return -1;
+ }
+
+ printf("start open '%s' for read...\n", rd_fifo);
+ if( (fdr_fifo=open(rd_fifo, O_RDONLY)) < 0 )
+ {
+ printf("Open fifo[%s] for chat read endpoint failure: %s\n", rd_fifo, strerror(errno));
+ return -1;
+ }
+ }
+
+ printf("start chating with another program now, please input message now: \n");
+ while( !g_stop )
+ {
+ FD_ZERO(&rdset);
+ FD_SET(STDIN_FILENO, &rdset);
+ FD_SET(fdr_fifo, &rdset);
+
+ rv = select(fdr_fifo+1, &rdset, NULL, NULL, NULL);
+ if( rv <= 0 )
+ {
+ printf("Select get timeout or error: %s\n", strerror(errno));
+ continue;
+ }
+
+ /* get data arrive from FIFO */
+ if( FD_ISSET(fdr_fifo, &rdset) )
+ {
+ memset(buf, 0, sizeof(buf));
+ rv=read(fdr_fifo, buf, sizeof(buf));
+ if( rv < 0)
+ {
+ printf("read data from FIFO get errorr: %s\n", strerror(errno));
+ break;
+ }
+ else if( 0==rv )
+ {
+ printf("Another side of FIFO get closed and program will exit now\n");
+ break;
+ }
+
+ printf("<-- %s", buf);
+ }
+
+ if( FD_ISSET(STDIN_FILENO, &rdset) )
+ {
+ memset(buf, 0, sizeof(buf));
+ fgets(buf, sizeof(buf), stdin);
+ write(fdw_fifo, buf, strlen(buf));
+ }
+ }
+}
+
+
+
+
--
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