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View the source code of a LKM

This is a discussion on View the source code of a LKM within the Linux Programming forums, part of the Platform Specific Boards category; is there a way to view a linux kernel module's source code?...

  1. #1
    Registered User Annonymous's Avatar
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    View the source code of a LKM

    is there a way to view a linux kernel module's source code?

  2. #2
    and the hat of wrongness Salem's Avatar
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    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  3. #3
    Registered User Annonymous's Avatar
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    I found the c file here ---> Index of /pub/Linux/utils/disk-management

    eject.c

    Code:
    /********************************************************************
     *
     *		L I N U X   E J E C T	C O M M A N D
     *
     *		  by Jeff Tranter (tranter@pobox.com)
     *
     ********************************************************************
     *
     * Copyright (C) 1994-2005 Jeff Tranter (tranter@pobox.com)
     *
     * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
     *
     ********************************************************************
     *
     * See the man page for a description of what this program does and what
     * the requirements to run it are.
     *
     */
    
    #include "i18n.h"
    
    #ifndef DEFAULTDEVICE
    #error DEFAULTDEVICE not set, check Makefile
    #endif
    
    #include <linux/version.h>
    /* handy macro found in 2.1 kernels, but not in older ones */
    #ifndef KERNEL_VERSION
    #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
    #endif
    
    #include <unistd.h>
    #include <stdlib.h>
    #include <stdio.h>
    #include <string.h>
    #include <fcntl.h>
    #include <limits.h>
    
    #ifdef GETOPTLONG
    #include <getopt.h>
    #endif /* GETOPTLONG */
    #include <errno.h>
    #include <regex.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <sys/ioctl.h>
    #include <sys/wait.h>
    #include <sys/mtio.h>
    #include <linux/types.h>
    #include <linux/cdrom.h>
    #if LINUX_VERSION_CODE < KERNEL_VERSION(2,1,0)
    #include <linux/ucdrom.h>
    #endif
    #include <linux/fd.h>
    #include <sys/mount.h>
    #include <scsi/scsi.h>
    #include <scsi/sg.h>
    #include <scsi/scsi_ioctl.h>
    #include <sys/time.h>
    
    /* Used by the ToggleTray() function. If ejecting the tray takes this
     * time or less, the tray was probably already ejected, so we close it
     * again.
     */
    #define TRAY_WAS_ALREADY_OPEN_USECS  200000	/* about 0.2 seconds */
    
    
    #define CLOSE(fd) if (close(fd)==-1) { \
        perror(programName); \
        exit(1); \
    }
    
    #define FCLOSE(fd) if (fclose(fd)==-1) { \
        perror(programName); \
        exit(1); \
    }
    
    /* Global Variables */
    const char *version = VERSION; /* program version */
    int a_option = 0; /* command flags and arguments */
    int c_option = 0;
    int d_option = 0;
    int f_option = 0;
    int h_option = 0;
    int n_option = 0;
    int q_option = 0;
    int r_option = 0;
    int s_option = 0;
    int t_option = 0;
    int T_option = 0;
    int v_option = 0;
    int x_option = 0;
    int p_option = 0;
    int m_option = 0;
    int a_arg = 0;
    int c_arg = 0;
    int x_arg = 0;
    char *programName; /* used in error messages */
    
    /*
     * These are the basenames of devices which can have multiple
     * partitions per device.
     */
    const char *partitionDevice[] = {
    	"hd",
    	"sd",
    	"xd",
    	"dos_hd",
    	"mfm",
    	"ad",
    	"ed",
    	"ftl",
    	"pd",
    	0};
    
    
    /* Display command usage on standard error and exit. */
    static void usage()
    {
    //    perror(_("%s: device is `%s'\n"));
    	fprintf(stderr,_(
    "Eject version %s by Jeff Tranter (tranter@pobox.com)\n"
    "Usage:\n"
    "  eject -h				-- display command usage and exit\n"
    "  eject -V				-- display program version and exit\n"
    "  eject [-vnrsfq] [<name>]		-- eject device\n"
    "  eject [-vn] -d			-- display default device\n"
    "  eject [-vn] -a on|off|1|0 [<name>]	-- turn auto-eject feature on or off\n"
    "  eject [-vn] -c <slot> [<name>]	-- switch discs on a CD-ROM changer\n"
    "  eject [-vn] -t [<name>]		-- close tray\n"
    "  eject [-vn] -T [<name>]		-- toggle tray\n"
    "  eject [-vn] -x <speed> [<name>]	-- set CD-ROM max speed\n"
    "Options:\n"
    "  -v\t-- enable verbose output\n"
    "  -n\t-- don't eject, just show device found\n"
    "  -r\t-- eject CD-ROM\n"
    "  -s\t-- eject SCSI device\n"
    "  -f\t-- eject floppy\n"
    "  -q\t-- eject tape\n"
    "  -p\t-- use /proc/mounts instead of /etc/mtab\n"
    "  -m\t-- do not unmount device even if it is mounted\n"
    )
    , version);
    #ifdef GETOPTLONG
    	fprintf(stderr,_(
    "Long options:\n"
    "  -h --help   -v --verbose	 -d --default\n"
    "  -a --auto   -c --changerslot  -t --trayclose  -x --cdspeed\n"
    "  -r --cdrom  -s --scsi	 -f --floppy\n"
    "  -q --tape   -n --noop	 -V --version\n"
    "  -p --proc   -m --no-unmount -T --traytoggle\n"));
    #endif /* GETOPTLONG */
    	fprintf(stderr,_(
    "Parameter <name> can be a device file or a mount point.\n"
    "If omitted, name defaults to `%s'.\n"
    "By default tries -r, -s, -f, and -q in order until success.\n"),
    			DEFAULTDEVICE);
      exit(1);
    }
    
    
    /* Handle command line options. */
    static void parse_args(int argc, char **argv, char **device)
    {
    	const char *flags = "a:c:x:dfhnqrstTvVpm";
    #ifdef GETOPTLONG
    	static struct option long_options[] =
    	{
    		{"help",	no_argument,	   NULL, 'h'},
    		{"verbose",	no_argument,	   NULL, 'v'},
    		{"default",	no_argument,	   NULL, 'd'},
    		{"auto",	required_argument, NULL, 'a'},
    		{"changerslot", required_argument, NULL, 'c'},
    		{"trayclose",	no_argument,	   NULL, 't'},
    		{"traytoggle",	no_argument,	   NULL, 'T'},
    		{"cdspeed",	required_argument, NULL, 'x'},
    		{"noop",	no_argument,	   NULL, 'n'},
    		{"cdrom",	no_argument,	   NULL, 'r'},
    		{"scsi",	no_argument,	   NULL, 's'},
    		{"floppy",	no_argument,	   NULL, 'f'},
    		{"tape",	no_argument,	   NULL, 'q'},
    		{"version",	no_argument,	   NULL, 'V'},
    		{"proc",	no_argument,	   NULL, 'p'},
    		{"no-unmount",	no_argument,	   NULL, 'm'},
    		{0, 0, 0, 0}
    	};
    	int option_index;
    #endif /* GETOPTLONG */
    	int c;
    
    #ifdef GETOPTLONG
    	while ((c = getopt_long(argc, argv, flags, long_options, &option_index)) != EOF) {
    #else
    	while ((c = getopt(argc, argv, flags)) != EOF) {
    #endif /* GETOPTLONG */
    		switch (c) {
    		  case 'a':
    			  a_option = 1;
    			  if (!strcmp(optarg, "0"))
    				  a_arg = 0;
    			  else if (!strcmp(optarg, "off"))
    				  a_arg = 0;
    			  else if (!strcmp(optarg, "1"))
    				  a_arg = 1;
    			  else if (!strcmp(optarg, "on"))
    				  a_arg = 1;
    			  else {
    				  fprintf(stderr, _("%s: invalid argument to --auto/-a option\n"), programName);
    				  exit(1);
    			  }
    			  break;
    		  case 'c':
    			  c_option = 1;
    			  /* atoi() returns 0 on error, so "0" must be parsed separately */
    			  if (!strcmp(optarg, "0"))
    				  c_arg = 0;
    			  else {
    				  c_arg = atoi(optarg);
    				  if (c_arg <= 0) {
    					  fprintf(stderr, _("%s: invalid argument to --changerslot/-c option\n"), programName);
    					  exit(1);
    				  }
    			  }
    			  break;
    		  case 'x':
    			  x_option = 1;
    			  if (!strcmp(optarg, "0"))
    				  x_arg = 0;
    			  else {
    				  x_arg = atoi(optarg);
    				  if (x_arg <= 0) {
    					  fprintf(stderr, _("%s: invalid argument to --cdspeed/-x option\n"), programName);
    					  exit(1);
    				  }
    			  }
    			  break;
    		  case 'd':
    			  d_option = 1;
    			  break;
    		  case 'f':
    			  f_option = 1;
    			  break;
    		  case 'h':
    			  usage();
    			  exit(0);
    			  break;
    		  case 'm':
    			  m_option = 1;
    			  break;
    		  case 'n':
    			  n_option = 1;
    			  break;
    		  case 'p':
    			  p_option = 1;
    			  break;
    		  case 'q':
    			  q_option = 1;
    			  break;
    		  case 'r':
    			  r_option = 1;
    			  break;
    		  case 's':
    			  s_option = 1;
    			  break;
    		  case 't':
    			  t_option = 1;
    			  break;
    		  case 'T':
    			  T_option = 1;
    			  break;
    		  case 'v':
    			  v_option = 1;
    			  break;
    		  case 'V':
    			  printf(_("eject version %s by Jeff Tranter (tranter@pobox.com)\n"), version);
    			  exit(0);
    			  break;
    		  case '?':
    			  exit(1);
    			  break;
    		}
    	}
    	/* check for a single additional argument */
    	if ((argc - optind) > 1) {
    		fprintf(stderr, _("%s: too many arguments\n"), programName);
    		exit(1);
    	}
    	if ((argc - optind) == 1) { /* one argument */
    		*device = strdup(argv[optind]);
    	}
    }
    
    
    /* Return 1 if file/device exists, 0 otherwise. */
    static int FileExists(const char *name)
    {
    
    	/*
    	 * access() uses the UID, not the EUID. This way a normal user
    	 * cannot find out if a file (say, /root/fubar) exists or not, even
    	 * if eject is SUID root
    	 */
    	if (access (name, F_OK) == 0) {
    		return 1;
    	}	else {
    		return 0;
    	}
    }
    
    
    /*
     * Given name, such as foo, see if any of the following exist:
     *
     * foo (if foo starts with '.' or '/')
     * /dev/foo
     * /media/foo
     * /mnt/foo
     * /dev/cdroms/foo
     * /dev/cdroms/foo0
     * /dev/dsk/foo
     * /dev/rdsk/foo
     * ./foo
     *
     * If found, return the full path. If not found, return 0.
     * Returns pointer to dynamically allocated string.
     */
    static char *FindDevice(const char *name)
    {
    	char *buf;
    
    	buf = (char *) malloc(strlen(name)+14); /* to allow for "/dev/cdroms/ + "0" + null */
    	if (buf==NULL) {
    		fprintf(stderr, _("%s: could not allocate memory\n"), programName);
    		exit(1);
    	}
    	if ((name[0] == '.') || (name[0] == '/')) {
    		strcpy(buf, name);
    		if (FileExists(buf))
    			return buf;
    	}
    
    	strcpy(buf, "/dev/");
    	strcat(buf, name);
    	if (FileExists(buf))
    		return buf;
    
    	strcpy(buf, "/media/");
    	strcat(buf, name);
    	if (FileExists(buf))
    		return buf;
    	
    	strcpy(buf, "/mnt/");
    	strcat(buf, name);
    	if (FileExists(buf))
    		return buf;
    
    	/* for devfs under Linux */
    	strcpy(buf, "/dev/cdroms/");
    	strcat(buf, name);
    	if (FileExists(buf))
    		return buf;
    
    	strcpy(buf, "/dev/cdroms/");
    	strcat(buf, name);
    	strcat(buf, "0");
    	if (FileExists(buf))
    		return buf;
    
    	/* for devfs under Solaris */
    	strcpy(buf, "/dev/rdsk/");
    	strcat(buf, name);
    	if (FileExists(buf))
    		return buf;
    
    	strcpy(buf, "/dev/dsk/");
    	strcat(buf, name);
    	if (FileExists(buf))
    		return buf;
    
    	strcpy(buf, "./");
    	strcat(buf, name);
    	if (FileExists(buf))
    		return buf;
    
    	free(buf);
    	buf = 0;
    	return 0;
    }
    
    
    /* Set or clear auto-eject mode. */
    static void AutoEject(int fd, int onOff)
    {
    	int status;
    
    	status = ioctl(fd, CDROMEJECT_SW, onOff);
    	if (status != 0) {
    		fprintf(stderr, _("%s: CD-ROM auto-eject command failed: %s\n"), programName, strerror(errno));
    		exit(1);
    	}
    }
    
    
    /*
     * Changer select. CDROM_SELECT_DISC is preferred, older kernels used
     * CDROMLOADFROMSLOT.
     */
    static void ChangerSelect(int fd, int slot)
    {
    	int status;
    
    #ifdef CDROM_SELECT_DISC
    	status = ioctl(fd, CDROM_SELECT_DISC, slot);
    	if (status < 0) {
    		fprintf(stderr, _("%s: CD-ROM select disc command failed: %s\n"), programName, strerror(errno));
    		exit(1);
    	}
    #elif defined CDROMLOADFROMSLOT
    	status = ioctl(fd, CDROMLOADFROMSLOT, slot);
    	if (status != 0) {
    		fprintf(stderr, _("%s: CD-ROM load from slot command failed: %s\n"), programName, strerror(errno));
    		exit(1);
    	}
    #else
        fprintf(stderr, _("%s: IDE/ATAPI CD-ROM changer not supported by this kernel\n"), programName);
    #endif
    }
    
    
    /*
     * Close tray. Not supported by older kernels.
     */
    static void CloseTray(int fd)
    {
    	int status;
    
    #ifdef CDROMCLOSETRAY
    	status = ioctl(fd, CDROMCLOSETRAY);
    	if (status != 0) {
    		fprintf(stderr, _("%s: CD-ROM tray close command failed: %s\n"), programName, strerror(errno));
    		exit(1);
    	}
    #else
        fprintf(stderr, _("%s: CD-ROM tray close command not supported by this kernel\n"), programName);
    #endif
    }
    
    /*
     * Toggle tray.
     *
     * Written by Benjamin Schwenk <benjaminschwenk@yahoo.de> and
     * Sybren Stuvel <sybren@thirdtower.com>
     *
     * Not supported by older kernels because it might use
     * CloseTray().
     *
     */
    static void ToggleTray(int fd)
    {
    	struct timeval time_start, time_stop;
    	int time_elapsed;
    
    #ifdef CDROMCLOSETRAY
    
    	/* Try to open the CDROM tray and measure the time therefor
    	 * needed.  In my experience the function needs less than 0.05
    	 * seconds if the tray was already open, and at least 1.5 seconds
    	 * if it was closed.  */
    	gettimeofday(&time_start, NULL);
    	
    	/* Send the CDROMEJECT command to the device. */
    	if (ioctl(fd, CDROMEJECT, 0) < 0) {
    		perror("ioctl");
    		exit(1);
    	}
    
    	/* Get the second timestamp, to measure the time needed to open
    	 * the tray.  */
    	gettimeofday(&time_stop, NULL);
    
    	time_elapsed = (time_stop.tv_sec * 1000000 + time_stop.tv_usec) -
    		(time_start.tv_sec * 1000000 + time_start.tv_usec);
    
    	/* If the tray "opened" too fast, we can be nearly sure, that it
    	 * was already open. In this case, close it now. Else the tray was
    	 * closed before. This would mean that we are done.  */
    	if (time_elapsed < TRAY_WAS_ALREADY_OPEN_USECS)
    		CloseTray(fd);
    
    #else
        fprintf(stderr, _("%s: CD-ROM tray toggle command not supported by this kernel\n"), programName);
    #endif
    	
    }
    
    /*
     * Select Speed of CD-ROM drive.
     * Thanks to Roland Krivanek (krivanek@fmph.uniba.sk)
     * http://dmpc.dbp.fmph.uniba.sk/~krivanek/cdrom_speed/
     */
    static void SelectSpeedCdrom(int fd, int speed)
    {
    	int status;
    
    #ifdef CDROM_SELECT_SPEED
    	status = ioctl(fd, CDROM_SELECT_SPEED, speed);
    	if (status != 0) {
    		fprintf(stderr, _("%s: CD-ROM select speed command failed: %s\n"), programName, strerror(errno));
    		exit(1);
    	}
    #else
        fprintf(stderr, _("%s: CD-ROM select speed command not supported by this kernel\n"), programName);
    #endif
    }
    
    
    /*
     * Eject using CDROMEJECT ioctl. Return 1 if successful, 0 otherwise.
     */
    static int EjectCdrom(int fd)
    {
    	int status;
    
    	status = ioctl(fd, CDROMEJECT);
    	return (status == 0);
    }
    
    
    /*
     * Eject using SCSI commands. Return 1 if successful, 0 otherwise.
     */
    static int EjectScsi(int fd)
    {
    	int status;
    	struct sdata {
    		int  inlen;
    		int  outlen;
    		char cmd[256];
    	} scsi_cmd;
    
    	scsi_cmd.inlen	= 0;
    	scsi_cmd.outlen = 0;
    	scsi_cmd.cmd[0] = ALLOW_MEDIUM_REMOVAL;
    	scsi_cmd.cmd[1] = 0;
    	scsi_cmd.cmd[2] = 0;
    	scsi_cmd.cmd[3] = 0;
    	scsi_cmd.cmd[4] = 0;
    	scsi_cmd.cmd[5] = 0;
    	status = ioctl(fd, SCSI_IOCTL_SEND_COMMAND, (void *)&scsi_cmd);
    	if (status != 0)
    		return 0;
    
    	scsi_cmd.inlen	= 0;
    	scsi_cmd.outlen = 0;
    	scsi_cmd.cmd[0] = START_STOP;
    	scsi_cmd.cmd[1] = 0;
    	scsi_cmd.cmd[2] = 0;
    	scsi_cmd.cmd[3] = 0;
    	scsi_cmd.cmd[4] = 1;
    	scsi_cmd.cmd[5] = 0;
    	status = ioctl(fd, SCSI_IOCTL_SEND_COMMAND, (void *)&scsi_cmd);
    	if (status != 0)
    		return 0;
    
    	scsi_cmd.inlen	= 0;
    	scsi_cmd.outlen = 0;
    	scsi_cmd.cmd[0] = START_STOP;
    	scsi_cmd.cmd[1] = 0;
    	scsi_cmd.cmd[2] = 0;
    	scsi_cmd.cmd[3] = 0;
    	scsi_cmd.cmd[4] = 2;
    	scsi_cmd.cmd[5] = 0;
    	status = ioctl(fd, SCSI_IOCTL_SEND_COMMAND, (void *)&scsi_cmd);
    	if (status != 0)
    		return 0;
    
    	/* force kernel to reread partition table when new disc inserted */
    	status = ioctl(fd, BLKRRPART);
    	return (status == 0);
    }
    
    
    /*
     * Eject using FDEJECT ioctl. Return 1 if successful, 0 otherwise.
     */
    static int EjectFloppy(int fd)
    {
    	int status;
    
    	status = ioctl(fd, FDEJECT);
    	return (status == 0);
    }
    
    
    /*
     * Eject using tape ioctl. Return 1 if successful, 0 otherwise.
     */
    static int EjectTape(int fd)
    {
    	int status;
    	struct mtop op;
    
    	op.mt_op = MTOFFL; /* rewind and eject */
    	op.mt_count = 0;   /* not used */
    	status = ioctl(fd, MTIOCTOP, &op);
    	return (status == 0);
    }
    
    
    /* Unmount a device. */
    static void Unmount(const char *fullName)
    {
    	int status;
    
    	switch (fork()) {
    	  case 0: /* child */
    		  seteuid(getuid()); /* reduce likelyhood of security holes when running setuid */
    		  if(p_option)
    			  execl("/bin/umount", "/bin/umount", fullName, "-n", NULL);
    		  else
    			  execl("/bin/umount", "/bin/umount", fullName, NULL);
    		  fprintf(stderr, _("%s: unable to exec /bin/umount of `%s': %s\n"),
    				  programName, fullName, strerror(errno));
    		  exit(1);
    		  break;
    	  case -1:
    		  fprintf(stderr, _("%s: unable to fork: %s\n"), programName, strerror(errno));
    		  break;
    	  default: /* parent */
    		  wait(&status);
    		  if (WIFEXITED(status) == 0) {
    			  fprintf(stderr, _("%s: unmount of `%s' did not exit normally\n"), programName, fullName);
    			  exit(1);
    		  }
    		  if (WEXITSTATUS(status) != 0) {
    			  fprintf(stderr, _("%s: unmount of `%s' failed\n"), programName, fullName);
    			  exit(1);
    		  }
    		  break;
    	}
    }
    
    
    /* Open a device file. */
    static int OpenDevice(const char *fullName)
    {
    	int fd = open(fullName, O_RDONLY|O_NONBLOCK);
    	if (fd == -1) {
    		fprintf(stderr, _("%s: unable to open `%s'\n"), programName, fullName);
    		exit(1);
    	}
    	return fd;
    }
    
    
    /*
     * Get major and minor device numbers for a device file name, so we
     * can check for duplicate devices.
     */
    static int GetMajorMinor(const char *name, int *maj, int *min)
    {
    	struct stat sstat;
    	*maj = *min = -1;
    	if (stat(name, &sstat) == -1)
    		return -1;
    	if (! S_ISBLK(sstat.st_mode))
    		return -1;
    	*maj = major(sstat.st_rdev);
    	*min = minor(sstat.st_rdev);
    	return 0;
    }
    
    
    /*
     * See if device has been mounted by looking in mount table.  If so, set
     * device name and mount point name, and return 1, otherwise return 0.
     */
    static int MountedDevice(const char *name, char **mountName, char **deviceName)
    {
    	FILE *fp;
    	char line[1024];
    	char s1[1024];
    	char s2[1024];
    	int rc;
    
    	int maj;
    	int min;
    
    	GetMajorMinor(name, &maj, &min);
    
    	fp = fopen((p_option ? "/proc/mounts" : "/etc/mtab"), "r");
    	if (fp == NULL)
    	{
    		fprintf(stderr, _("unable to open %s: %s\n"), (p_option ? "/proc/mounts" : "/etc/mtab"), strerror(errno));
    		exit(1);
    	}
    
    	while (fgets(line, sizeof(line), fp) != 0) {
    		rc = sscanf(line, "%1023s %1023s", s1, s2);
    		if (rc >= 2) {
    			int mtabmaj, mtabmin;
    			GetMajorMinor(s1, &mtabmaj, &mtabmin);
    			if (((strcmp(s1, name) == 0) || (strcmp(s2, name) == 0)) ||
    				((maj != -1) && (maj == mtabmaj) && (min == mtabmin))) {
    				FCLOSE(fp);
    				*deviceName = strdup(s1);
    				*mountName = strdup(s2);
    				return 1;
    			}
    		}
    	}
    	*deviceName = 0;
    	*mountName = 0;
    	FCLOSE(fp);
    	return 0;
    }
    
    
    /*
     * See if device can be mounted by looking in /etc/fstab.
     * If so, set device name and mount point name, and return 1,
     * otherwise return 0.
     */
    static int MountableDevice(const char *name, char **mountName, char **deviceName)
    {
    	FILE *fp;
    	char line[1024];
    	char s1[1024];
    	char s2[1024];
    	int rc;
    
    	fp = fopen("/etc/fstab", "r");
    	if (fp == NULL) {
    /*
     * /etc/fstab may be unreadable in some situations due to passwords in the
     * file.
     */
    /*		fprintf(stderr, _("%s: unable to open /etc/fstab: %s\n"), programName, strerror(errno));
    		exit(1);*/
    		if (v_option) {
    			printf( _("%s: unable to open /etc/fstab: %s\n"), programName, strerror(errno));
    		}
    		return -1;
    	}
    
    	while (fgets(line, sizeof(line), fp) != 0) {
    		rc = sscanf(line, "%1023s %1023s", s1, s2);
    		if (rc >= 2 && s1[0] != '#' && strcmp(s2, name) == 0) {
    			FCLOSE(fp);
    			*deviceName = strdup(s1);
    			*mountName = strdup(s2);
    			return 1;
    		}
    	}
    	FCLOSE(fp);
    	return 0;
    }
    
    
    /*
     * Step through mount table and unmount all devices that match a regular
     * expression.
     */
    static void UnmountDevices(const char *pattern)
    {
    	regex_t preg;
    	FILE *fp;
    	char s1[1024];
    	char s2[1024];
    	char line[1024];
    	int status;
    
    	if (regcomp(&preg, pattern, REG_EXTENDED)!=0) {
    		perror(programName);
    		exit(1);
    	}
    
    	fp = fopen((p_option ? "/proc/mounts" : "/etc/mtab"), "r");
    	if (fp == NULL)
    	{
    		fprintf(stderr, _("unable to open %s: %s\n"),(p_option ? "/proc/mounts" : "/etc/mtab"), strerror(errno));
    		exit(1);
    	}
    
    	while (fgets(line, sizeof(line), fp) != 0) {
    		status = sscanf(line, "%1023s %1023s", s1, s2);
    		if (status >= 2) {
    			status = regexec(&preg, s1, 0, 0, 0);
    			if (status == 0) {
    				if (v_option)
    					printf(_("%s: unmounting `%s'\n"), programName, s1);
    				Unmount(s1);
    				regfree(&preg);
    			}
    		}
    	}
    	FCLOSE(fp);
    }
    
    
    /* Check if name is a symbolic link. If so, return what it points to. */
    static char *SymLink(const char *name)
    {
    	int status;
    	char s1[PATH_MAX];
    	char s2[PATH_MAX];
    	char s4[PATH_MAX];
    	char result[PATH_MAX];
    	char *s3;
    
    	memset(s1, 0, sizeof(s1));
    	memset(s2, 0, sizeof(s2));
    	memset(s4, 0, sizeof(s4));
    	memset(result, 0, sizeof(result));
    
    	status = readlink(name, s1, sizeof(s1) - 1);
    
    	if (status == -1)
    		return 0;
    
    	s1[status] = 0;
    	if (s1[0] == '/') { /* absolute link */
    		return strdup(s1);
    	} else { /* relative link, add base name */
    		strncpy(s2, name, sizeof(s2)-1);
    		s3 = strrchr(s2, '/');
    		if (s3 != 0) {
    			s3[1] = 0;
    			snprintf(result, sizeof(result)-1, "%s%s", s2, s1);
    		}
    	}
    	realpath(result, s4);
    	return strdup(s4);
    }
    
    
    /*
     * Given a name, see if it matches a pattern for a device that can have
     * multiple partitions.  If so, return a regular expression that matches
     * partitions for that device, otherwise return 0.
     */
    static char *MultiplePartitions(const char *name)
    {
    	int i = 0;
    	int status;
    	regex_t preg;
    	char pattern[256];
    	char *result = 0;
    
    	for (i = 0; partitionDevice[i] != 0; i++) {
    		/* look for ^/dev/foo[a-z]([0-9]?[0-9])?$, e.g. /dev/hda1 */
    		strcpy(pattern, "^/dev/");
    		strcat(pattern, partitionDevice[i]);
    		strcat(pattern, "[a-z]([0-9]?[0-9])?$");
    		regcomp(&preg, pattern, REG_EXTENDED|REG_NOSUB);
    		status = regexec(&preg, name, 1, 0, 0);
    		regfree(&preg);
    		if (status == 0) {
    			result = (char *) malloc(strlen(name) + 25);
    			strcpy(result, name);
    			result[strlen(partitionDevice[i]) + 6] = 0;
    			strcat(result, "([0-9]?[0-9])?$");
    			if (v_option)
    				printf(_("%s: `%s' is a multipartition device\n"), programName, name);
    			return result;
    		}
    	}
    	if (v_option)
    		printf(_("%s: `%s' is not a multipartition device\n"), programName, name);
    	return 0;
    }
    
    
    /* handle -x option */
    void HandleXOption(char *deviceName)
    {
    	int fd; 	   /* file descriptor for device */
    	if (x_option) {
    		if (v_option)
    		{
    			if (x_arg == 0)
    				printf(_("%s: setting CD-ROM speed to auto\n"), programName);
    			else
    				printf(_("%s: setting CD-ROM speed to %dX\n"), programName, x_arg);
    		}
    		fd = OpenDevice(deviceName);
    		SelectSpeedCdrom(fd, x_arg);
    		exit(0);
    	}
    }
    
    
    /* main program */
    int main(int argc, char **argv)
    {
    	const char *defaultDevice = DEFAULTDEVICE;  /* default if no name passed by user */
    	int worked = 0;    /* set to 1 when successfully ejected */
    	char *device = 0;  /* name passed from user */
    	char *fullName;    /* expanded name */
    	char *deviceName;  /* name of device */
    	char *linkName;    /* name of device's symbolic link */
    	char *mountName;   /* name of device's mount point */
    	int fd; 	   /* file descriptor for device */
    	int mounted = 0;   /* true if device is mounted */
    	int mountable = 0; /* true if device is in /etc/fstab */
    	char *pattern;	   /* regex for device if multiple partitions */
    	int ld = 6;	   /* symbolic link max depth */
    
    	I18NCODE
    
    	/* program name is global variable used by other procedures */
    	programName = strdup(argv[0]);
    
    	/* parse the command line arguments */
    	parse_args(argc, argv, &device);
    
    
    	/* handle -d option */
    	if (d_option) {
    		printf(_("%s: default device: `%s'\n"), programName, defaultDevice);
    		exit(0);
    	}
    
    	/* if no device, use default */
    	if (device == 0) {
    		device = strdup(defaultDevice);
    		if (v_option)
    			printf(_("%s: using default device `%s'\n"), programName, device);
    	}
    
    	/* Strip any trailing slash from name in case user used bash/tcsh
    	   style filename completion (e.g. /mnt/cdrom/) */
    	if (device[strlen(device)-1] == '/')
    		device[strlen(device)-1] = 0;
    
    	if (v_option)
    		printf(_("%s: device name is `%s'\n"), programName, device);
    
    	/* figure out full device or mount point name */
    	fullName = FindDevice(device);
    	if (fullName == 0) {
    		fprintf(stderr, _("%s: unable to find or open device for: `%s'\n"), programName, device);
    		exit(1);
    	}
    	if (v_option)
    		printf(_("%s: expanded name is `%s'\n"), programName, fullName);
    
    	/* check for a symbolic link */
    	while ((linkName = SymLink(fullName)) && (ld > 0)) {
    		if (v_option)
    			printf(_("%s: `%s' is a link to `%s'\n"), programName, fullName, linkName);
    		free(fullName);
    		fullName = strdup(linkName);
    		free(linkName);
    		linkName = 0;
    		ld--;
    	}
    	/* handle max depth exceeded option */
    	if (ld <= 0) {
    		printf(_("%s: maximum symbolic link depth exceeded: `%s'\n"), programName, fullName);
    		exit(1);
    	}
    
    	/* if mount point, get device name */
    	mounted = MountedDevice(fullName, &mountName, &deviceName);
    	if (v_option) {
    		if (mounted)
    			printf(_("%s: `%s' is mounted at `%s'\n"), programName, deviceName, mountName);
    		else
    			printf(_("%s: `%s' is not mounted\n"), programName, fullName);
    	}
    	if (!mounted) {
    		deviceName = strdup(fullName);
    	}
    
    	/* if not currently mounted, see if it is a possible mount point */
    	if (!mounted) {
    		mountable = MountableDevice(fullName, &mountName, &deviceName);
    		/* if return value -1 then fstab could not be read */
    		if (v_option && mountable >= 0) {
    			if (mountable)
    				printf(_("%s: `%s' can be mounted at `%s'\n"), programName, deviceName, mountName);
    			else
    				printf(_("%s: `%s' is not a mount point\n"), programName, fullName);
    		}
    	}
    
    	/* handle -n option */
    	if (n_option) {
    		printf(_("%s: device is `%s'\n"), programName, deviceName);
    		if (v_option)
    			printf(_("%s: exiting due to -n/--noop option\n"), programName);
    		exit(0);
    	}
    
    	/* handle -a option */
    	if (a_option) {
    		if (v_option) {
    			if (a_arg)
    				printf(_("%s: enabling auto-eject mode for `%s'\n"), programName, deviceName);
    			else
    				printf(_("%s: disabling auto-eject mode for `%s'\n"), programName, deviceName);
    		}
    		fd = OpenDevice(deviceName);
    		AutoEject(fd, a_arg);
    		exit(0);
    	}
    
    	/* handle -t option */
    	if (t_option) {
    		if (v_option)
    			printf(_("%s: closing tray\n"), programName);
    		fd = OpenDevice(deviceName);
    		CloseTray(fd);
    		HandleXOption(deviceName);
    		exit(0);
    	}
    
    	/* handle -T option */
    	if (T_option) {
    		if (v_option)
    			printf(_("%s: toggling tray\n"), programName);
    		fd = OpenDevice(deviceName);
    		ToggleTray(fd);
    		HandleXOption(deviceName);
    		exit(0);
    	}
    
    	/* handle -x option only */
    	if (!c_option) HandleXOption(deviceName);
    
    	/* unmount device if mounted */
    	if ((m_option != 1) && mounted) {
    		if (v_option)
    			printf(_("%s: unmounting `%s'\n"), programName, deviceName);
    		Unmount(deviceName);
    	}
    
    	/* if it is a multipartition device, unmount any other partitions on
    	   the device */
    	pattern = MultiplePartitions(deviceName);
    	if ((m_option != 1) && (pattern != 0))
    		UnmountDevices(pattern);
    
    	/* handle -c option */
    	if (c_option) {
    		if (v_option)
    			printf(_("%s: selecting CD-ROM disc #%d\n"), programName, c_arg);
    		fd = OpenDevice(deviceName);
    		ChangerSelect(fd, c_arg);
    		HandleXOption(deviceName);
    		exit(0);
    	}
    
    	/* if user did not specify type of eject, try all four methods */
    	if ((r_option + s_option + f_option + q_option) == 0) {
    		r_option = s_option = f_option = q_option = 1;
    	}
    
    	/* open device */
    	fd = OpenDevice(deviceName);
    
    	/* try various methods of ejecting until it works */
    	if (r_option) {
    		if (v_option)
    			printf(_("%s: trying to eject `%s' using CD-ROM eject command\n"), programName, deviceName);
    		worked = EjectCdrom(fd);
    		if (v_option) {
    			if (worked)
    				printf(_("%s: CD-ROM eject command succeeded\n"), programName);
    			else
    				printf(_("%s: CD-ROM eject command failed\n"), programName);
    		}
    	}
    
    	if (s_option && !worked) {
    		if (v_option)
    			printf(_("%s: trying to eject `%s' using SCSI commands\n"), programName, deviceName);
    		worked = EjectScsi(fd);
    		if (v_option) {
    			if (worked)
    				printf(_("%s: SCSI eject succeeded\n"), programName);
    			else
    				printf(_("%s: SCSI eject failed\n"), programName);
    		}
    	}
    
    	if (f_option && !worked) {
    		if (v_option)
    			printf(_("%s: trying to eject `%s' using floppy eject command\n"), programName, deviceName);
    		worked = EjectFloppy(fd);
    		if (v_option) {
    			if (worked)
    				printf(_("%s: floppy eject command succeeded\n"), programName);
    			else
    				printf(_("%s: floppy eject command failed\n"), programName);
    		}
    	}
    
    	if (q_option && !worked) {
    		if (v_option)
    			printf(_("%s: trying to eject `%s' using tape offline command\n"), programName, deviceName);
    		worked = EjectTape(fd);
    		if (v_option) {
    			if (worked)
    				printf(_("%s: tape offline command succeeded\n"), programName);
    			else
    				printf(_("%s: tape offline command failed\n"), programName);
    		}
    	}
    
    	if (!worked) {
    		fprintf(stderr, _("%s: unable to eject, last error: %s\n"), programName, strerror(errno));
    		exit(1);
    	}
    
    	/* cleanup */
    	CLOSE(fd);
    	free(device);
    	free(deviceName);
    	free(fullName);
    	free(linkName);
    	free(mountName);
    	free(pattern);
    	exit(0);
    }
    1100 lines of code. Thats fvcking rediculous!!!!

  4. #4
    Programming Wraith GReaper's Avatar
    Join Date
    Apr 2009
    Location
    Greece
    Posts
    1,624
    Quote Originally Posted by Annonymous View Post
    1100 lines of code. Thats fvcking rediculous!!!!
    What did you expect? OS programming isnot for the faint of heart! Try it, and then judge it.

    What's really ridiculous is what you just did, posting that big bulk of code.
    rags_to_riches likes this.
    Devoted my life to programming...

  5. #5
    Registered User Annonymous's Avatar
    Join Date
    Apr 2011
    Location
    Jackson, New Jersey, United States
    Posts
    302
    What did you expect? OS programming isnot for the faint of heart! Try it, and then judge it.
    Yeah i understand it has to be top notch because it is going to be used by everyone who uses Linux. That wasnt done by one man either!

    What's really ridiculous is what you just did, posting that big bulk of code.
    Yeah i know lol and...??

  6. #6
    and the hat of wrongness Salem's Avatar
    Join Date
    Aug 2001
    Location
    The edge of the known universe
    Posts
    32,498
    So you have a program which handles a couple of dozen permutations of options in a SAFE manner (like unmounting volumes).
    50 lines per feature point is pretty good going IMO.

    As opposed to some 5-line hack hard-coded for a single device which has no regard for anyone else who might be using the device.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  7. #7
    Registered User Annonymous's Avatar
    Join Date
    Apr 2011
    Location
    Jackson, New Jersey, United States
    Posts
    302
    haha right man. Good point Salem!!

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