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