[cpp] view plain copy 如何操作伪终端： 伪终端的使用是成对出现的，分为master 和 slaver 主设备：/dev/ptmx （i850上的主设备名） 从设备：动态生成：/dev/pts/0.......x 功能：写入主设备的信息，可以从从设备上读出；写入从设备的信息，可以从主设备读出。用以实现对串口的多路复用。 以下是测试代码 Ubuntu 下的编译方法： gcc -Wall ptyhost.c -o ptyhost -util /lib/libutil-2.9.so # include <stdio.h> # include <stdlib.h> # include <string.h> # include <unistd.h> # include <sys/types.h> # include <linux/limits.h> # include <pty.h> /* for openpty and forkpty */ #include <utmp.h> /* for login_tty */ #include <time.h> # include <pty.h> /* for openpty and forkpty */ #include <utmp.h> /* for login_tty */ int main(int argc, char *argv[]) { int rtnVal=0; int mpty, spty, c=0, dev=0; char *pName=NULL; char ptyBuff[100] = {'/0'}; char sptyname[20] = {'/0'}; rtnVal = openpty(&mpty, &spty, sptyname, NULL, NULL);/＊该函数遍历系统中的伪终端匹配对，如果能找到一组未使用的，则返回1，否则返回－1，成功返回时mpty会带出匹配对中主设备的文件描述符，spty会带出从设备的文件描述符，第三个实参如果不空的话，它会带出从设备的路径名！后边两个参数是在设置终端属性，一般是不要的，据说伪终端对属性设置是忽略的＊/ // Check if Pseudo-Term pair was created if(rtnVal != -1) { pName = ptsname(mpty);//get slave device name, the arg is the master device printf("Name of slave side is <%s> fd = %d/n", pName, spty); strcpy(sptyname, pName); printf("my sptyname is %s/n",sptyname); //test write to mpty and read from spty************* char temp[50] = {"hell/nworld ! i have write to mpty!"}; char temp2[100] = {'/0'}; c = write(mpty,temp,5); if(c <=0) printf("ERROR : can not write to mpty/n"); sleep(3); printf("write %d charactors to mpty success/n",c); sleep(3); printf("try to read from spty/n"); sleep(3); c = read(spty,temp2,5); if(c <=0) printf("ERROR : can not read from mpty/n"); printf("read from spty %d charactors success/n",c); printf("/n>>>>> %s <<<<</n/n___________________/n",temp2); //************************************************** // Go into loop and read what is sent to Slave side of pair while(1) { c = read(mpty, ptyBuff, 100); if(c > 0) { printf("###-<%d>/n", c); printf("buff:__|%s",ptyBuff); } } } else { printf("PseudoTerm, creation failed.../n"); } return rtnVal; } http://blog.163.com/coder_jack@126 伪终端的操作： 以下是源码，来自/fsl_myandroid_r6/external/qemu/vl.c line 2545 r7里面都已经没有了！真快呀！哈哈 /* Once Solaris has openpty(), this is going to be removed. */ int openpty(int *amaster, int *aslave, char *name, struct termios *termp, struct winsize *winp) { const char *slave; int mfd = -1, sfd = -1; *amaster = *aslave = -1; mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY); if (mfd < 0) goto err; if (grantpt(mfd) == -1 || unlockpt(mfd) == -1) goto err; if ((slave = ptsname(mfd)) == NULL) goto err; if ((sfd = open(slave, O_RDONLY | O_NOCTTY)) == -1) goto err; if (ioctl(sfd, I_PUSH, "ptem") == -1 || (termp != NULL && tcgetattr(sfd, termp) < 0)) goto err; if (amaster) *amaster = mfd; if (aslave) *aslave = sfd; if (winp) ioctl(sfd, TIOCSWINSZ, winp); return 0; err: if (sfd != -1) close(sfd); close(mfd); return -1; } http://blog.163.com/coder_jack@126
