LXR busybox/util-linux/eject.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * eject implementation for busybox
   4 *
   5 * Copyright (C) 2004  Peter Willis <psyphreak@phreaker.net>
   6 * Copyright (C) 2005  Tito Ragusa <farmatito@tiscali.it>
   7 *
   8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9 */
  10
  11/*
  12 * This is a simple hack of eject based on something Erik posted in #uclibc.
  13 * Most of the dirty work blatantly ripped off from cat.c =)
  14 */
  15//config:config EJECT
  16//config:       bool "eject (4 kb)"
  17//config:       default y
  18//config:       select PLATFORM_LINUX
  19//config:       help
  20//config:       Used to eject cdroms. (defaults to /dev/cdrom)
  21//config:
  22//config:config FEATURE_EJECT_SCSI
  23//config:       bool "SCSI support"
  24//config:       default y
  25//config:       depends on EJECT
  26//config:       help
  27//config:       Add the -s option to eject, this allows to eject SCSI-Devices and
  28//config:       usb-storage devices.
  29
  30//applet:IF_EJECT(APPLET(eject, BB_DIR_USR_BIN, BB_SUID_DROP))
  31
  32//kbuild:lib-$(CONFIG_EJECT) += eject.o
  33
  34//usage:#define eject_trivial_usage
  35//usage:       "[-t] [-T] [DEVICE]"
  36//usage:#define eject_full_usage "\n\n"
  37//usage:       "Eject DEVICE or default /dev/cdrom\n"
  38//usage:        IF_FEATURE_EJECT_SCSI(
  39//usage:     "\n        -s      SCSI device"
  40//usage:        )
  41//usage:     "\n        -t      Close tray"
  42//usage:     "\n        -T      Open/close tray (toggle)"
  43
  44#include <sys/mount.h>
  45#include "libbb.h"
  46#if ENABLE_FEATURE_EJECT_SCSI
  47/* Must be after libbb.h: they need size_t */
  48# include "fix_u32.h"
  49# include <scsi/sg.h>
  50# include <scsi/scsi.h>
  51#endif
  52
  53#define dev_fd 3
  54
  55/* Code taken from the original eject (http://eject.sourceforge.net/),
  56 * refactored it a bit for busybox (ne-bb@nicoerfurth.de) */
  57
  58#if ENABLE_FEATURE_EJECT_SCSI
  59static void eject_scsi(const char *dev)
  60{
  61        static const char sg_commands[3][6] ALIGN1 = {
  62                { ALLOW_MEDIUM_REMOVAL, 0, 0, 0, 0, 0 },
  63                { START_STOP, 0, 0, 0, 1, 0 },
  64                { START_STOP, 0, 0, 0, 2, 0 }
  65        };
  66
  67        unsigned i;
  68        unsigned char sense_buffer[32];
  69        unsigned char inqBuff[2];
  70        sg_io_hdr_t io_hdr;
  71
  72        if ((ioctl(dev_fd, SG_GET_VERSION_NUM, &i) < 0) || (i < 30000))
  73                bb_error_msg_and_die("not a sg device or old sg driver");
  74
  75        memset(&io_hdr, 0, sizeof(sg_io_hdr_t));
  76        io_hdr.interface_id = 'S';
  77        io_hdr.cmd_len = 6;
  78        io_hdr.mx_sb_len = sizeof(sense_buffer);
  79        io_hdr.dxfer_direction = SG_DXFER_NONE;
  80        /* io_hdr.dxfer_len = 0; */
  81        io_hdr.dxferp = inqBuff;
  82        io_hdr.sbp = sense_buffer;
  83        io_hdr.timeout = 2000;
  84
  85        for (i = 0; i < 3; i++) {
  86                io_hdr.cmdp = (void *)sg_commands[i];
  87                ioctl_or_perror_and_die(dev_fd, SG_IO, (void *)&io_hdr, "%s", dev);
  88        }
  89
  90        /* force kernel to reread partition table when new disc is inserted */
  91        ioctl(dev_fd, BLKRRPART);
  92}
  93#else
  94# define eject_scsi(dev) ((void)0)
  95#endif
  96
  97/* various defines swiped from linux/cdrom.h */
  98#define CDROMCLOSETRAY            0x5319  /* pendant of CDROMEJECT  */
  99#define CDROMEJECT                0x5309  /* Ejects the cdrom media */
 100#define CDROM_DRIVE_STATUS        0x5326  /* Get tray position, etc. */
 101/* drive status possibilities returned by CDROM_DRIVE_STATUS ioctl */
 102#define CDS_TRAY_OPEN        2
 103
 104#define FLAG_CLOSE  1
 105#define FLAG_SMART  2
 106#define FLAG_SCSI   4
 107
 108static void eject_cdrom(unsigned flags, const char *dev)
 109{
 110        int cmd = CDROMEJECT;
 111
 112        if (flags & FLAG_CLOSE
 113         || ((flags & FLAG_SMART) && ioctl(dev_fd, CDROM_DRIVE_STATUS) == CDS_TRAY_OPEN)
 114        ) {
 115                cmd = CDROMCLOSETRAY;
 116        }
 117
 118        ioctl_or_perror_and_die(dev_fd, cmd, NULL, "%s", dev);
 119}
 120
 121int eject_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 122int eject_main(int argc UNUSED_PARAM, char **argv)
 123{
 124        unsigned flags;
 125        const char *device;
 126
 127        flags = getopt32(argv, "^" "tT"IF_FEATURE_EJECT_SCSI("s")
 128                        "\0" "?1:t--T:T--t"
 129        );
 130        device = argv[optind] ? argv[optind] : "/dev/cdrom";
 131
 132        /* We used to do "umount <device>" here, but it was buggy
 133           if something was mounted OVER cdrom and
 134           if cdrom is mounted many times.
 135
 136           This works equally well (or better):
 137           #!/bin/sh
 138           umount /dev/cdrom
 139           eject /dev/cdrom
 140        */
 141
 142        xmove_fd(xopen_nonblocking(device), dev_fd);
 143
 144        if (ENABLE_FEATURE_EJECT_SCSI && (flags & FLAG_SCSI))
 145                eject_scsi(device);
 146        else
 147                eject_cdrom(flags, device);
 148
 149        if (ENABLE_FEATURE_CLEAN_UP)
 150                close(dev_fd);
 151
 152        return EXIT_SUCCESS;
 153}
 154