eject

eject

关注
发信
关注(28)粉丝(399)

从 C 代码中弹出 Cd rom 时出现输入/输出错误

本文介绍了从 C 代码中弹出 Cd rom 时出现输入/输出错误的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我的 CD-Rom 在 Ubuntu 14.10 上有问题.我正在尝试运行这段代码，它写入 ioctl: Input/output error 并且 open() 返回数字 3.哪里应该是错误?我的 CDROM PATH 对吗?当我在终端写eject "dev/cdrom"时，它被弹出了.

I Have problems with my CD-Rom on Ubuntu 14.10. I`m trying to run this piece of code, and it writes ioctl: Input/output error and open() returns number 3. Where should be an mistake? is my CDROM PATH right? When I wrote eject "dev/cdrom" in terminal, it is ejected.

/* eject.c
** Copyright Paul Dwerryhouse, 1997-2004
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <linux/cdrom.h>

#define CDDEVICE "/dev/cdrom"           /* CDROM device */

int main(int argc,char **argv)
{
   int cdrom;                           /* CDROM device file descriptor */

   /* Open the CDROM device. The linux/cdrom.h header file specifies that
   ** it must be given the O_NONBLOCK flag when opening. My tests showed
   ** that if this isn't done, this program will not work.
   */
   if ((cdrom = open(CDDEVICE,O_RDONLY | O_NONBLOCK)) < 0) {
        perror("open");
        exit(1);
   }

   /* Use ioctl to send the CDROMEJECT command to the device
   */
   if (ioctl(cdrom,CDROMEJECT,0)<0) {
        perror("ioctl");
        exit(1);
   }

   close(cdrom);
}

这是strace输出.

Here is strace output.

execve("./frca", ["./frca"], [/* 76 vars */]) = 0
brk(0)                                  = 0x2015000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4240016000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=136133, ...}) = 0
mmap(NULL, 136133, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f423fff4000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\37\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1845024, ...}) = 0
mmap(NULL, 3953344, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f423fa30000
mprotect(0x7f423fbeb000, 2097152, PROT_NONE) = 0
mmap(0x7f423fdeb000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1bb000) = 0x7f423fdeb000
mmap(0x7f423fdf1000, 17088, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f423fdf1000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f423fff3000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f423fff1000
arch_prctl(ARCH_SET_FS, 0x7f423fff1740) = 0
mprotect(0x7f423fdeb000, 16384, PROT_READ) = 0
mprotect(0x600000, 4096, PROT_READ)     = 0
mprotect(0x7f4240018000, 4096, PROT_READ) = 0
munmap(0x7f423fff4000, 136133)          = 0
open("/dev/cdrom", O_RDONLY|O_NONBLOCK) = 3
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4240015000
write(1, "3\n", 23
)                      = 2
ioctl(3, CDROMEJECT, 0)                 = -1 EIO (Input/output error)
dup(2)                                  = 4
fcntl(4, F_GETFL)                       = 0x8002 (flags O_RDWR|O_LARGEFILE)
brk(0)                                  = 0x2015000
brk(0x2036000)                          = 0x2036000
fstat(4, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4240014000
lseek(4, 0, SEEK_CUR)                   = -1 ESPIPE (Illegal seek)
write(4, "ioctl: Input/output error\n", 26ioctl: Input/output error
) = 26
close(4)                                = 0
munmap(0x7f4240014000, 4096)            = 0
exit_group(1)                           = ?
+++ exited with 1 +++

系统弹出:

bo@bo-ThinkPad-Edge-E530:~$ strace eject
execve("/usr/bin/eject", ["eject"], [/* 75 vars */]) = 0
brk(0)                                  = 0x7f3dbd946000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3dbd094000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=136133, ...}) = 0
mmap(NULL, 136133, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f3dbd072000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\37\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1845024, ...}) = 0
mmap(NULL, 3953344, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f3dbcaae000
mprotect(0x7f3dbcc69000, 2097152, PROT_NONE) = 0
mmap(0x7f3dbce69000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1bb000) = 0x7f3dbce69000
mmap(0x7f3dbce6f000, 17088, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f3dbce6f000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3dbd071000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3dbd06f000
arch_prctl(ARCH_SET_FS, 0x7f3dbd06f740) = 0
mprotect(0x7f3dbce69000, 16384, PROT_READ) = 0
mprotect(0x7f3dbd29f000, 4096, PROT_READ) = 0
mprotect(0x7f3dbd096000, 4096, PROT_READ) = 0
munmap(0x7f3dbd072000, 136133)          = 0
brk(0)                                  = 0x7f3dbd946000
brk(0x7f3dbd967000)                     = 0x7f3dbd967000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=4427728, ...}) = 0
mmap(NULL, 4427728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f3dbc675000
close(3)                                = 0
access("/dev/cdrom", F_OK)              = 0
readlink("/dev/cdrom", "sr0", 4095)     = 3
lstat("/dev", {st_mode=S_IFDIR|0755, st_size=4300, ...}) = 0
lstat("/dev/sr0", {st_mode=S_IFBLK|0660, st_rdev=makedev(11, 0), ...}) = 0
readlink("/dev/sr0", 0x7fff014d9428, 4095) = -1 EINVAL (Invalid argument)
stat("/dev/sr0", {st_mode=S_IFBLK|0660, st_rdev=makedev(11, 0), ...}) = 0
open("/etc/mtab", O_RDONLY)             = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=911, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3dbd093000
read(3, "/dev/sda5 / ext4 rw,errors=remou"..., 4096) = 911
stat("/dev/sda5", {st_mode=S_IFBLK|0660, st_rdev=makedev(8, 5), ...}) = 0
stat("proc", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("sysfs", 0x7fff014dc740)           = -1 ENOENT (No such file or directory)
stat("none", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("none", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("none", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("none", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("udev", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("devpts", 0x7fff014dc740)          = -1 ENOENT (No such file or directory)
stat("tmpfs", 0x7fff014dc740)           = -1 ENOENT (No such file or directory)
stat("none", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("none", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("none", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("none", 0x7fff014dc740)            = -1 ENOENT (No such file or directory)
stat("/dev/sda6", {st_mode=S_IFBLK|0660, st_rdev=makedev(8, 6), ...}) = 0
stat("binfmt_misc", 0x7fff014dc740)     = -1 ENOENT (No such file or directory)
stat("systemd", 0x7fff014dc740)         = -1 ENOENT (No such file or directory)
stat("gvfsd-fuse", 0x7fff014dc740)      = -1 ENOENT (No such file or directory)
read(3, "", 4096)                       = 0
close(3)                                = 0
munmap(0x7f3dbd093000, 4096)            = 0
open("/etc/fstab", O_RDONLY)            = 3
fstat(3, {st_mode=S_IFREG|0664, st_size=595, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3dbd093000
read(3, "# /etc/fstab: static file system"..., 4096) = 595
read(3, "", 4096)                       = 0
close(3)                                = 0
munmap(0x7f3dbd093000, 4096)            = 0
stat("/dev/sr0", {st_mode=S_IFBLK|0660, st_rdev=makedev(11, 0), ...}) = 0
open("/usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=26258, ...}) = 0
mmap(NULL, 26258, PROT_READ, MAP_SHARED, 3, 0) = 0x7f3dbd08d000
close(3)                                = 0
geteuid()                               = 1000
open("/dev/sr0", O_RDWR|O_NONBLOCK)     = 3
ioctl(3, CDROMEJECT, 0x7f3dbd9490e0)    = -1 EIO (Input/output error)
ioctl(3, SG_GET_VERSION_NUM, 0x7fff014dd4b8) = 0
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[1e, 00, 00, 00, 00, 00], mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=10000, flags=0, status=00, masked_status=00, sb[0]=[], host_status=0, driver_status=0, resid=0, duration=16, info=0}) = 0
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[1b, 00, 00, 00, 01, 00], mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=10000, flags=0, status=00, masked_status=00, sb[0]=[], host_status=0, driver_status=0, resid=0, duration=856, info=0}) = 0
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[1b, 00, 00, 00, 02, 00], mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=10000, flags=0, status=02, masked_status=01, sb[18]=[70, 00, 05, 00, 00, 00, 00, 0a, 00, 00, 00, 00, 53, 02, 00, 00, 00, 00], host_status=0, driver_status=0x8, resid=0, duration=4, info=0x1}) = 0
ioctl(3, FDEJECT, 0x7fff014dd4c8)       = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(3, MGSL_IOCGPARAMS or MMTIMER_GETRES or MTIOCTOP or SNDCTL_MIDI_MPUMODE, 0x7fff014dd4c8) = -1 ENOTTY (Inappropriate ioctl for device)
open("/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=2570, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3dbd08c000
read(4, "# Locale name alias data base.\n#"..., 4096) = 2570
read(4, "", 4096)                       = 0
close(4)                                = 0
munmap(0x7f3dbd08c000, 4096)            = 0
open("/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US/LC_MESSAGES/eject.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/eject.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en_US/LC_MESSAGES/eject.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en/LC_MESSAGES/eject.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, "eject: unable to eject, last err"..., 67eject: unable to eject, last error: Inappropriate ioctl for device
) = 67
exit_group(1)                           = ?
+++ exited with 1 +++

推荐答案

出于某种原因，您的 cdrom 拒绝了 CDROMEJECT ioctl 但它接受用于弹出托盘的 sg(SCSI 通用)命令.

For some reason, your cdrom rejects the CDROMEJECT ioctl but it does accept the sg (SCSI Generic) commands designed to eject the tray.

open("/dev/sr0", O_RDWR|O_NONBLOCK)     = 3
ioctl(3, CDROMEJECT, 0x7f3dbd9490e0)    = -1 EIO (Input/output error)
ioctl(3, SG_GET_VERSION_NUM, 0x7fff014dd4b8) = 0
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[1e, 00, 00, 00, 00, 00], mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=10000, flags=0, status=00, masked_status=00, sb[0]=[], host_status=0, driver_status=0, resid=0, duration=16, info=0}) = 0
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[1b, 00, 00, 00, 01, 00], mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=10000, flags=0, status=00, masked_status=00, sb[0]=[], host_status=0, driver_status=0, resid=0, duration=856, info=0}) = 0
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[1b, 00, 00, 00, 02, 00], mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=10000, flags=0, status=02, masked_status=01, sb[18]=[70, 00, 05, 00, 00, 00, 00, 0a, 00, 00, 00, 00, 53, 02, 00, 00, 00, 00], host_status=0, driver_status=0x8, resid=0, duration=4, info=0x1}) = 0
ioctl(3, FDEJECT, 0x7fff014dd4c8)       = -1 ENOTTY (Inappropriate ioctl for device)

ioctl(3, SG_IO, ..."命令序列执行以下操作:

The "ioctl(3, SG_IO, ..." sequence of commands do the following:

  • ALLOW_MEDIUM_REMOVAL
  • START_STOP 带有效载荷 1
  • START_STOP 带有效载荷 2
  • ALLOW_MEDIUM_REMOVAL
  • START_STOP with payload 1
  • START_STOP with payload 2

参考文献:

https://github.com/karelzak/util-linux/blob/master/sys-utils/eject.c#L590http://git.buildroot.net/busybox/plain/miscutils/eject.c?h=1_17_stablehttps://github.com/dylex/android_external_busybox/blob/master/miscutils/eject.c#L35

这篇关于从 C 代码中弹出 Cd rom 时出现输入/输出错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！

05-22 22:21
Powered by LMLPHP ©2024 eject 0.048242