enhance.c

xorp源码hg

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <locale.h>

#include <unistd.h>
#include <termios.h>

#include <fcntl.h>
#include <sys/termios.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <dirent.h>

#if HAVE_SYSV_PTY
#include <stropts.h>    /* System-V stream I/O */
char *ptsname(int fd);
int grantpt(int fd);
int unlockpt(int fd);
#endif

#include "libtecla.h"

/*
 * Pseudo-terminal devices are found in the following directory.
 */
#define PTY_DEV_DIR "/dev/"

/*
 * Pseudo-terminal controller device file names start with the following
 * prefix.
 */
#define PTY_CNTRL "pty"

/*
 * Pseudo-terminal slave device file names start with the following
 * prefix.
 */
#define PTY_SLAVE "tty"

/*
 * Specify the maximum suffix length for the control and slave device
 * names.
 */
#define PTY_MAX_SUFFIX 10

/*
 * Set the maximum length of the master and slave terminal device filenames,
 * including space for a terminating '\0'.
 */
#define PTY_MAX_NAME (sizeof(PTY_DEV_DIR)-1 + \
		      (sizeof(PTY_SLAVE) > sizeof(PTY_CNTRL) ? \
		       sizeof(PTY_SLAVE) : sizeof(PTY_CNTRL))-1 \
		      + PTY_MAX_SUFFIX + 1)
/*
 * Set the maximum length of an input line.
 */
#define PTY_MAX_LINE 4096

/*
 * Set the size of the buffer used for accumulating bytes written by the
 * user's terminal to its stdout.
 */
#define PTY_MAX_READ 1000

/*
 * Set the amount of memory used to record history.
 */
#define PTY_HIST_SIZE 10000

/*
 * Set the timeout delay used to check for quickly arriving
 * sequential output from the application.
 */
#define PTY_READ_TIMEOUT 100000    /* micro-seconds */

static int pty_open_master(const char *prog, int *cntrl, char *slave_name);
static int pty_open_slave(const char *prog, char *slave_name);
static int pty_child(const char *prog, int slave, char *argv[]);
static int pty_parent(const char *prog, int cntrl);
static int pty_stop_parent(int waserr, int cntrl, GetLine *gl, char *rbuff);
static GL_FD_EVENT_FN(pty_read_from_program);
static int pty_write_to_fd(int fd, const char *string, int n);
static void pty_child_exited(int sig);
static int pty_master_readable(int fd, long usec);

/*.......................................................................
 * Run a program with enhanced terminal editing facilities.
 *
 * Usage:
 *  enhance program [args...]
 */
int main(int argc, char *argv[])
{
  int cntrl = -1;  /* The fd of the pseudo-terminal controller device */
  int slave = -1;  /* The fd of the pseudo-terminal slave device */
  pid_t pid;       /* The return value of fork() */
  int status;      /* The return statuses of the parent and child functions */
  char slave_name[PTY_MAX_NAME]; /* The filename of the slave end of the */
                                 /*  pseudo-terminal. */
  char *prog;      /* The name of the program (ie. argv[0]) */
/*
 * Check the arguments.
 */
  if(argc < 2) {
    fprintf(stderr, "Usage: %s <program> [arguments...]\n", argv[0]);
    return 1;
  };
/*
 * Get the name of the program.
 */
  prog = argv[0];
/*
 * If the user has the LC_CTYPE or LC_ALL environment variables set,
 * enable display of characters corresponding to the specified locale.
 */
  (void) setlocale(LC_CTYPE, "");
/*
 * If the program is taking its input from a pipe or a file, or
 * sending its output to something other than a terminal, run the
 * program without tecla.
 */
  if(!isatty(STDIN_FILENO) || !isatty(STDOUT_FILENO)) {
    if(execvp(argv[1], argv + 1) < 0) {
      fprintf(stderr, "%s: Unable to execute %s (%s).\n", prog, argv[1],
	      strerror(errno));
      fflush(stderr);
      _exit(1);
    };
  };
/*
 * Open the master side of a pseudo-terminal pair, and return
 * the corresponding file descriptor and the filename of the
 * slave end of the pseudo-terminal.
 */
  if(pty_open_master(prog, &cntrl, slave_name))
    return 1;
/*
 * Set up a signal handler to watch for the child process exiting.
 */
  signal(SIGCHLD, pty_child_exited);
/*
 * The above signal handler sends the parent process a SIGINT signal.
 * This signal is caught by gl_get_line(), which resets the terminal
 * settings, and if the application signal handler for this signal
 * doesn't abort the process, gl_get_line() returns NULL with errno
 * set to EINTR. Arrange to ignore the signal, so that gl_get_line()
 * returns and we have a chance to cleanup.
 */
  signal(SIGINT, SIG_IGN);
/*
 * We will read user input in one process, and run the user's program
 * in a child process.
 */
  pid = fork();
  if(pid < 0) {
    fprintf(stderr, "%s: Unable to fork child process (%s).\n", prog,
	    strerror(errno));
    return 1;
  };
/*
 * Are we the parent?
 */
  if(pid!=0) {
    status = pty_parent(prog, cntrl);
    close(cntrl);
  } else {
    close(cntrl); /* The child doesn't use the slave device */
    signal(SIGCHLD, pty_child_exited);
    if((slave = pty_open_slave(prog, slave_name)) >= 0) {
      status = pty_child(prog, slave, argv + 1);
      close(slave);
    } else {
      status = 1;
    };
  };
  return status;
}

/*.......................................................................
 * Open the master side of a pseudo-terminal pair, and return
 * the corresponding file descriptor and the filename of the
 * slave end of the pseudo-terminal.
 *
 * Input/Output:
 *  prog  const char *  The name of this program.
 *  cntrl        int *  The file descriptor of the pseudo-terminal
 *                      controller device will be assigned tp *cntrl.
 *  slave_name  char *  The file-name of the pseudo-terminal slave device
 *                      will be recorded in slave_name[], which must have
 *                      at least PTY_MAX_NAME elements.
 * Output:
 *  return       int    0 - OK.
 *                      1 - Error.
 */
static int pty_open_master(const char *prog, int *cntrl, char *slave_name)
{
  char master_name[PTY_MAX_NAME]; /* The filename of the master device */
  DIR *dir;                       /* The directory iterator */
  struct dirent *file;            /* A file in "/dev" */
/*
 * Mark the controller device as not opened yet.
 */
  *cntrl = -1;
/*
 * On systems with the Sys-V pseudo-terminal interface, we don't
 * have to search for a free master terminal. We just open /dev/ptmx,
 * and if there is a free master terminal device, we are given a file
 * descriptor connected to it.
 */
#if HAVE_SYSV_PTY
  *cntrl = open("/dev/ptmx", O_RDWR);
  if(*cntrl >= 0) {
/*
 * Get the filename of the slave side of the pseudo-terminal.
 */
    char *name = ptsname(*cntrl);
    if(name) {
      if(strlen(name)+1 > PTY_MAX_NAME) {
	fprintf(stderr, "%s: Slave pty filename too long.\n", prog);
	return 1;
      };
      strcpy(slave_name, name);
/*
 * If unable to get the slave name, discard the controller file descriptor,
 * ready to try a search instead.
 */
    } else {
      close(*cntrl);
      *cntrl = -1;
    };
  } else {
#endif
/*
 * On systems without /dev/ptmx, or if opening /dev/ptmx failed,
 * we open one master terminal after another, until one that isn't
 * in use by another program is found.
 *
 * Open the devices directory.
 */
    dir = opendir(PTY_DEV_DIR);
    if(!dir) {
      fprintf(stderr, "%s: Couldn't open %s (%s)\n", prog, PTY_DEV_DIR,
	      strerror(errno));
      return 1;
    };
/*
 * Look for pseudo-terminal controller device files in the devices
 * directory.
 */
    while(*cntrl < 0 && (file = readdir(dir))) {
      if(strncmp(file->d_name, PTY_CNTRL, sizeof(PTY_CNTRL)-1) == 0) {
/*
 * Get the common extension of the control and slave filenames.
 */
	const char *ext = file->d_name + sizeof(PTY_CNTRL)-1;
	if(strlen(ext) > PTY_MAX_SUFFIX)
	  continue;
/*
 * Attempt to open the control file.
 */
	strcpy(master_name, PTY_DEV_DIR);
	strcat(master_name, PTY_CNTRL);
	strcat(master_name, ext);
	*cntrl = open(master_name, O_RDWR);
	if(*cntrl < 0)
	  continue;
/*
 * Attempt to open the matching slave file.
 */
	strcpy(slave_name, PTY_DEV_DIR);
	strcat(slave_name, PTY_SLAVE);
	strcat(slave_name, ext);
      };
    };
    closedir(dir);
#if HAVE_SYSV_PTY
  };
#endif
/*
 * Did we fail to find a pseudo-terminal pair that we could open?
 */
  if(*cntrl < 0) {
    fprintf(stderr, "%s: Unable to find a free pseudo-terminal.\n", prog);
    return 1;
  };
/*
 * System V systems require the program that opens the master to
 * grant access to the slave side of the pseudo-terminal.
 */
#ifdef HAVE_SYSV_PTY
  if(grantpt(*cntrl) < 0 ||
     unlockpt(*cntrl) < 0) {
    fprintf(stderr, "%s: Unable to unlock terminal (%s).\n", prog,
	    strerror(errno));
    return 1;
  };
#endif
/*
 * Success.
 */
  return 0;
}

/*.......................................................................
 * Open the slave end of a pseudo-terminal.
 *
 * Input:
 *  prog   const char *  The name of this program.
 *  slave_name   char *  The filename of the slave device.
 * Output:
 *  return        int    The file descriptor of the successfully opened
 *                       slave device, or < 0 on error.
 */
static int pty_open_slave(const char *prog, char *slave_name)
{
  int fd;  /* The file descriptor of the slave device */
/*
 * Place the process in its own process group. In system-V based
 * OS's, this ensures that when the pseudo-terminal is opened, it
 * becomes the controlling terminal of the process.
 */
  if(setsid() < 0) {
    fprintf(stderr, "%s: Unable to form new process group (%s).\n", prog,
	    strerror(errno));
    return -1;
  };
/*
 * Attempt to open the specified device.
 */
  fd = open(slave_name, O_RDWR);
  if(fd < 0) {
    fprintf(stderr, "%s: Unable to open pseudo-terminal slave device (%s).\n",
	    prog, strerror(errno));
    return -1;
  };
/*
 * On system-V streams based systems, we need to push the stream modules
 * that implement pseudo-terminal and termio interfaces. At least on
 * Solaris, which pushes these automatically when a slave is opened,
 * this is redundant, so ignore errors when pushing the modules.
 */
#if HAVE_SYSV_PTY