eject.c

在linux下多媒体开发实例linux下多媒体开发

/*
 *		L I N U X   E J E C T   C O M M A N D
 *
 * Copyright (C) 1994-96 Jeff Tranter ([e-mail])
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 ********************************************************************
 *
 * See the man page for a description of what this program does and what
 * the requirements to run it are.
 * 
 * It was developed using:
 * - Linux kernel 1.1.72
 * - gcc 2.5.8
 * - Panasonic CR-562-B CD-ROM drive
 * 
 * Jeff Tranter ([e-mail])
 */

#include <stdlib.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/mount.h>
#include <linux/cdrom.h>

/* set the default device here */
char default_device[255];

/* default options */
int f_option = 0;  /* force eject even if mounted */
int d_option = 0;  /* display default device */
int n_option = 0;  /* display nicknames */
int a_option = 0;  /* auto-eject */
int a_arg = 0;     /* argument to -a option */
int v_option = 0;  /* verbose mode */
int u_option = 0;  /* unmount first */
char device[256];  /* device name */

typedef struct {
  char *name;
  char *device;
} nickname_t;

/* table of device nicknames */
nickname_t nickname[] = { 
  { "cdrom",  "/dev/cdrom" },
  { "sbpcd" , "/dev/sbpcd" },
  { "sbpcd0", "/dev/sbpcd0" },
  { "sbpcd1", "/dev/sbpcd1" },
  { "sbpcd2", "/dev/sbpcd2" },
  { "sbpcd3", "/dev/sbpcd3" },
  { "cdu31a", "/dev/cdu31a" },
  { "cdu535", "/dev/cdu535" },
  { "mcd",    "/dev/mcd" },
  { "lmscd",  "/dev/lmscd" },
  { "scd0",   "/dev/scd0" },
  { "scd1",   "/dev/scd1" },
  { "cd0",    "/dev/cd0" },
  { "cd1",    "/dev/cd1" },
  { "sr0",    "/dev/sr0" },
  { "sr1",    "/dev/sr1" },
  { "sra",    "/dev/sra" },
  { "srb",    "/dev/srb" },
  /* next entry indicates end of table */
  { 0, 0 }
};

/* display command usage on standard error and exit */
void usage()
{
  fprintf(stderr,
	  "eject [-f][-u][-v]                 -- eject default device\n"
	  "eject [-f][-u][-v] <nickname>      -- eject device by nickname\n"
	  "eject [-f][-u][-v] <device-name>   -- eject device by device name\n"
	  "eject -d                           -- display default device\n"
	  "eject -n                           -- display device nicknames\n"
	  "eject -a [on|off|1|0] [-v]         -- turn auto-eject feature on or off\n"
	  "\n"
	  "Options:\n"
	  "    -f  force eject even if device is mounted.\n"
	  "    -u  unmount before forcing an eject.\n"
	  "    -v  enables verbose output.\n"
	  );
  exit(1);
}

/* handle command line options */
void parse_args(int argc, char **argv)
{
  const char     *flags = "fdna:uv";
  int             c;

  while ((c = getopt(argc, argv, flags)) != EOF) {
    switch (c) {
    case 'f':
      f_option = 1;
      break;
    case 'd':
      d_option = 1;
      break;
    case 'n':
      n_option = 1;
      break;
    case 'a':
      a_option = 1;
      /* make some poor guesses at what means on and off */
      if (!strcmp(optarg, "0"))
	a_arg = 0;
      else if (!strcmp(optarg, "off"))
	a_arg = 0;
      else if (!strcmp(optarg, "aus"))
	a_arg = 0;
      else if (!strcmp(optarg, "ferme"))
	a_arg = 0;
      else if (!strcmp(optarg, "1"))
	a_arg = 1;
      else if (!strcmp(optarg, "on"))
	a_arg = 1;
      else if (!strcmp(optarg, "auf"))
	a_arg = 1;
      else if (!strcmp(optarg, "allumee"))
	a_arg = 1;
      else
	usage();
      break;
    case 'u':
      u_option = 1;
      break;
    case 'v':
      v_option = 1;
      break;
    case '?':
      usage();
      break;
    }
  }

  /* check for a single additional argument */
  if ((argc - optind) > 1)
    usage(); /* too many arguments */
  
  if ((argc - optind) == 1)
    strcpy(device, argv[optind]); /* one argument */
}

int main(int argc, char **argv)
{
  int fd;           /* file descriptor for CD-ROM device */
  int status;       /* return status for system calls */
  int i;            /* loop counter */
  char s[255];      /* for error messages */
  char s1[256] = { 0 }; /* for reading /etc/mtab */
  char s2[256];     /* "   "       "         */
  char dummy[256];  /* "   "       "         */
  char umount_cmd[256] = "/bin/umount "; /* umount command string */
  char *s3;         /* general purpose */
  FILE *fp;         /* for reading /etc/mtab */

  /* get default device from $CDROM environment variable; if not set then use compiled in default */
  s3 = getenv("CDROM");
  if (s3 != NULL)
    strcpy(default_device, s3);
  else
    strcpy(default_device, "/dev/cdrom");
  
  /* make default device the default */
  strcpy(device, default_device);
  
  /* parse the command line arguments */
  parse_args(argc, argv);
  
  /* handle -d option */
  if (d_option) {
    printf("eject: default device is `%s'\n", default_device);
    exit(0);
  }

  /* handle -n option */  
  if (n_option) {
    printf("eject: device nicknames:\n");
    printf("Nickname  Device\n");
    printf("--------  ----------\n");
    for (i = 0 ; nickname[i].name != 0 ; i++)
      printf("%-8s  %-8s\n", nickname[i].name, nickname[i].device);
    exit(0);
  }

  if (v_option)
    printf("eject: device name is `%s'\n", device);

  /* check if device is a nickname */
  for (i = 0 ; nickname[i].name != 0 ; i++)
    if (!strcmp(device, nickname[i].name)) {
      if (v_option)
	printf("eject: `%s' is a nickname for `%s'\n", device, nickname[i].device);
      strcpy(device, nickname[i].device);
      break;
    }

  /* check if device is a symbolic link. If so, find out what it points to */
  status = readlink(device, s1, sizeof(s1));
  if (status != -1) {
    if (s1[0] == '/') {
      /* absolute link */
      strcpy(s2, s1);
    } else {
      /* a relative link */
      strcpy(s2, device);
      s3 = strrchr(s2, '/');
      if (s3 != 0) {
	s3[1] = 0;
	strcat(s2, s1);
      }
    }
    if (v_option)
      printf("eject: `%s' is a link to `%s'\n", device, s2);
    strcpy(device, s2);
  }

  /* open device */  
  fd = open(device, O_RDONLY);
  if (fd < 0) {
    sprintf(s, "eject: open failed for `%s'", device);
    perror(s);
    exit(1);
  }

  /* handle auto-eject option */
  if (a_option) {
#ifdef CDROMEJECT_SW
    if (v_option)
      if (a_arg)
	printf("eject: enabling auto-eject mode\n");
      else
	printf("eject: disabling auto-eject mode\n");
    status = ioctl(fd, CDROMEJECT_SW, a_arg);
    if (status != 0) {
      sprintf(s, "eject: CDROMEJECT_SW ioctl failed for `%s'", device);
      perror(s);
      exit(1);
    }
#else
    printf("eject: auto-eject not supported by kernel\n");
#endif
    exit(0);
  }
  
  /* see if device has been mounted by looking in /etc/mtab */
  fp = fopen("/etc/mtab", "r");
  while (!feof(fp)) {
    fscanf(fp, "%s %s %s %s %s %s", s1, s2, dummy, dummy, dummy, dummy);
    if (!strcmp(s1, device)) {
      if (!f_option) {
	printf("eject: `%s' is mounted at `%s', not ejected\n", s1, s2);
	exit(1);
      } else {
	if (v_option)
	  printf("eject: `%s' is mounted at `%s'\n", s1, s2);
	if (u_option) {
	  if (v_option)
	    printf("eject: trying to unmount `%s'\n", s1);
	  strcat(umount_cmd, s1);      /* setup umount command */
	  status = system(umount_cmd); /* do it */
	  if ((status == -1) || (status == 127)) {
	    sprintf(s, "eject: unmount of `%s' failed", s1);
	    perror(s);
	  }
	}
      }
      break;
    }
  }
  fclose(fp);
  
  /* eject */  
  status = ioctl(fd, CDROMEJECT);
  if (status != 0) {
    sprintf(s, "eject: CDROMEJECT ioctl failed for `%s'", device);
    perror(s);
    exit(1);
  }
  
  /* close device */
  status = close(fd);
  if (status != 0) {
    sprintf(s, "eject: close failed for `%s'", device);
    perror(s);
    exit(1);
  }
  
  exit(0);
}