我想检测一个USB连接并安装其相应的分区。我尝试使用udev.i可以在/dev/bus/usb/001或/002中找到设备。但是从中我找不到它使用的分区。因此，如果添加了分区，则使用UDEV搜索块分区和安装。EG/DEV/SDA1。但这是一个临时解决方案。我想要的是使用UDEV或其他东西检测USB连接，并找到它具有哪个分区并安装它。
我的代码：
#include <libudev.h>
#include <stdio.h>
#include "dmutil.h"
#include <pthread.h>
#include <unistd.h>
/*
Thread which detects devices.
*/
void * udev_listener(void * i)
{
struct udev *udev;
udev = udev_new();
if (!udev) {
printf("Can't create udevn");
exit(1);
}
std::string mount_path_for_udev_listner = DEFAULT_MOUNT_PATH;
printf("nn **********nUdev_listner is asked to mount usb to %s ....",mount_path_for_udev_listner.c_str());
struct udev_device *dev;
struct udev_monitor *mon;
mon = udev_monitor_new_from_netlink(udev, "udev");
assert(mon != NULL);
/* int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor,const char *subsystem, const char *devtype);
filters to select messages that get delivered to a listener.
On Success it returns an integer greater than, or equal to, 0. On failure, a negative error code is returned.
*/
assert(udev_monitor_filter_add_match_subsystem_devtype(mon, "block", NULL) >=0);
udev_monitor_enable_receiving(mon);
/* Get the file descriptor (fd) for the monitor.
This fd will get passed to select() */
int fd = udev_monitor_get_fd(mon);
/* Begin polling for udev events. Events occur when devices attached to the system are added, removed, or change state.
udev_monitor_receive_device() will return a device object representing the device which changed and what type of change occured.
The select() system call is used to ensure that the call to udev_monitor_receive_device() will not block.
This section will run continuously, calling usleep() at the end of each pass. This is to use udev_monitor in a non-blocking way. */
while (1)
{
/*
int select(int nfds, fd_set *readfds, fd_set *writefds,fd_set *exceptfds, struct timeval *timeout);
select() allows a program to monitor multiple file descriptors, waiting until one or more of the file descriptors
become "ready" for some class of I/O operation.
Set up the call to select(). In this case, select() will only operate on a single file descriptor, the one associated
with our udev_monitor. Note that the timeval object is set to 0, which will cause select() to not block. */
fd_set fds;
struct timeval tv;
int ret;
FD_ZERO(&fds); //clear fds
FD_SET(fd, &fds);// Add fd to fds
/*
The timeout argument specifies the interval that select() should block waiting for a file descriptor to become ready.
This interval will be rounded up to the system clock granularity, and kernel scheduling delays mean that the
blocking interval may overrun by a small amount. If both fields of the timeval structure are zero, then select()
returns immediately. (This is useful for polling.)If timeout is NULL (no timeout), select() can block indefinitely.
*/
tv.tv_sec = 0;
tv.tv_usec = 0;
/*
nfds specifies how big the list of file descriptors is because the total number can be vast.
So, if you want to monitor file descriptors 24-31, you'd set nfds to 32.
man - nfds is the highest-numbered file descriptor in any of the three sets, plus 1.
*/
ret = select(fd+1, &fds, NULL, NULL, &tv);
/* Check if our file descriptor has received data. */
if (ret > 0 && FD_ISSET(fd, &fds)) {
printf("nselect() says there should be datan");
/* Make the call to receive the device.
select() ensured that this will not block. */
dev = udev_monitor_receive_device(mon);
if (dev) {
printf("Got Devicen");
printf(" Node: %sn", udev_device_get_devnode(dev));
printf(" Subsystem: %sn", udev_device_get_subsystem(dev));
printf(" Devtype: %sn", udev_device_get_devtype(dev));
printf(" syspath:%sn",udev_device_get_syspath(dev));
printf(" sysname:%sn",udev_device_get_sysname(dev));
printf(" devpath:%sn",udev_device_get_devpath(dev));
printf(" subsystem:%sn",udev_device_get_subsystem(dev));
printf(" Action: %sn", udev_device_get_action(dev));
std::string devtype=udev_device_get_devtype(dev);
std::string action=udev_device_get_action(dev);
std::string devnode=udev_device_get_devnode(dev);
if(devtype.compare("partition")==0 && action.compare("add") == 0)
{
printf("A new partition detected at %snTrying to mount to %s",devnode.c_str(),mount_path_for_udev_listner.c_str());
int ret = mount_disk(devnode,mount_path_for_udev_listner);
if(ret == 0)
{
printf("nSystem returns %d, Mounting successn",ret);
}
else{
printf("n*****Error no %dn",errno);
}
}
if(devtype.compare("partition")==0 && action.compare("remove") == 0)
{
printf("Partition removal detected, trying to unmount...n");
int ret=umount_disk();
if(ret==0){
printf("nSystem returns %dn",ret);
printf("unmount successfulln");
}
else{
printf("nThe partition unmounting FAILED:n ");
}
}
udev_device_unref(dev);
}
else {
printf("No Device from receive_device(). An error occured.n");
}
}
usleep(250*1000);
printf(".");
fflush(stdout);
}
pthread_exit(NULL);
}
我得到了答案。我只需要为USB设备添加一个过滤器即可。如果我获得了一个设备作为USB和Block，则可以使用该分区并安装。
assert(udev_monitor_filter_add_match_subsystem_devtype(mon, "block", NULL)>=0);
assert(udev_monitor_filter_add_match_subsystem_devtype(mon, "usb","usb-device") >=0);
我从https://askubuntu.com/questions/285539/detect-and-mount-devices
复制了此文件。 sudo lsusb 将告诉您USB设备Linux检测到了哪些。是USB存储设备安装还是被检测到的是单独的问题。 sudo lsusb -v 将提供冗长的输出，如果OS真正不识别设备，则可能比您想要的更多信息。
另外，您可以在插入USB设备之前和之后比较 /dev 中的设备列表。有很多方法可以做到。我可能只会使用：
ls -l /dev/* | wc -l
这将为您提供许多公认的设备。在插入设备之前和之后进行操作会告诉您是否在 /dev/中分配了该设备。
另一个选项是查看DMESG插入USB设备时发生的事情。 dmesg 可能会告诉您诸如设备如何失败之类的事情。
如果您无法安装的USB设备在LSUSB列表上，则可以尝试安装设备。在这一点上，很高兴知道文件系统类型。 sudo fdisk -l 将以ID的形式告诉您文件系统类型。您可能必须查找ID号。在线有很多参考文献。一旦知道设备列表，即 /dev/hda1 和文件系统类型，您可以尝试使用MAINT命令安装设备手动。
sudo mount /dev/hda1 /home/user/Desktop/whereEver
您可能必须确保将设备安装在存在的位置。如果操作系统识别文件系统，则如果文件系统不是本机文件系统类型，则MOUNT可能会工作。您可能必须指定安装的标志。
从 dmesg 中发布输出（并非全部，仅在插入USB设备时从周围出发）和 sudo lsusb。
您可以找到Linux/unix：如果尝试确定设备类型时，设备文件很有帮助。
我正在写这篇文章，假设您所有未识别的设备都是块类型设备。有很多方法可以解决此类问题和许多可能的解决方案。需要更具体的信息来提供解决方案。
也有许多GUI应用程序可以做同样的事情。您可以尝试在"磁盘实用程序"中寻找插入的硬件。
检测附件USB设备的另一种方法是DBUS或HAL（但是HAL被认为是弃用的），请参阅此方法如何检测插入的USB和Linux热插图