C 如何获取SD卡事件的通知?
我想检查SD卡是否存在,并接收SD卡添加/删除通知 到目前为止,我已经使用了C 如何获取SD卡事件的通知?,c,linux,udev,C,Linux,Udev,我想检查SD卡是否存在,并接收SD卡添加/删除通知 到目前为止,我已经使用了libudev,并且制作了一个监听SD卡事件的小应用程序 代码如下所示: #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <stddef.h> #include <errno.h> #include <sys/time
libudev
,并且制作了一个监听SD卡事件的小应用程序
代码如下所示:
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <errno.h>
#include <sys/time.h> //debug -> remove me
#include <libudev.h>
#define ADD_FILTER "add"
#define REMOVE_FILTER "remove"
#define SUBSYSTEM_FILTER "block"
#define ATTR_FILTER "ID_MODEL"
#define SD_ATTR_VALUE "SD_MMC"
#define ATTR_ACTIVE_SD "ID_PART_TABLE_TYPE"
static bool isDeviceSD(struct udev_device *device);
static bool isDevPresent(struct udev *device);
static void print_device(struct udev_device *device, const char *source); //for debugging -> remove me
static bool s_bSD_present;
int main()
{
struct udev *udev;
struct udev_monitor *udev_monitor = NULL;
fd_set readfds;
s_bSD_present = false;
udev = udev_new();
if (udev == NULL)
{
printf("udev_new FAILED \n");
return 1;
}
s_bSD_present = isDevPresent(udev);
if(s_bSD_present)
{
printf("+++SD is plugged in \n");
}
else
{
printf("---SD is not plugged in \n");
}
udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
if (udev_monitor == NULL) {
printf("udev_monitor_new_from_netlink FAILED \n");
return 1;
}
//add some filters
if( udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, SUBSYSTEM_FILTER, NULL) < 0 )
{
printf("udev_monitor_filter_add_match_subsystem_devtype FAILED \n");
return 1;
}
if (udev_monitor_enable_receiving(udev_monitor) < 0)
{
printf("udev_monitor_enable_receiving FAILED \n");
return 1;
}
while (1) {
printf("Polling for new data... \n");
int fdcount = 0;
FD_ZERO(&readfds);
if (udev_monitor != NULL)
{
FD_SET(udev_monitor_get_fd(udev_monitor), &readfds);
}
fdcount = select(udev_monitor_get_fd(udev_monitor)+1, &readfds, NULL, NULL, NULL);
if (fdcount < 0)
{
if (errno != EINTR)
printf("Error receiving uevent message\n");
continue;
}
if ((udev_monitor != NULL) && FD_ISSET(udev_monitor_get_fd(udev_monitor), &readfds))
{
struct udev_device *device;
device = udev_monitor_receive_device(udev_monitor);
if (device == NULL)
continue;
//check the action
const char* szAction = udev_device_get_action(device);
if( strcmp(szAction, ADD_FILTER) == 0)
{
if( !s_bSD_present && isDeviceSD(device) )
{
s_bSD_present = true;
printf("+++SD has been plugged in \n");
}
}
else if( strcmp(szAction, REMOVE_FILTER) == 0 )
{
if( s_bSD_present && isDeviceSD(device) )
{
s_bSD_present = false;
printf("---SD has been removed \n");
}
}
udev_device_unref(device);
}
}
return 0;
}
static bool isDeviceSD(struct udev_device *device)
{
bool retVal = false;
struct udev_list_entry *list_entry = 0;
struct udev_list_entry* model_entry = 0;
struct udev_list_entry* active_sd_entry = 0;
list_entry = udev_device_get_properties_list_entry(device);
model_entry = udev_list_entry_get_by_name(list_entry, ATTR_FILTER);
if( 0 != model_entry )
{
const char* szModelValue = udev_list_entry_get_value(model_entry);
active_sd_entry = udev_list_entry_get_by_name(list_entry, ATTR_ACTIVE_SD);
if(strcmp(szModelValue, SD_ATTR_VALUE) == 0 && active_sd_entry != 0)
{
printf("Device is SD \n");
retVal = true;
//print_device(device, "UDEV");
}
}
return retVal;
}
static bool isDevPresent(struct udev *device)
{
bool retVal = false;
struct udev_enumerate *enumerate;
struct udev_list_entry *devices, *dev_list_entry;
enumerate = udev_enumerate_new(device);
udev_enumerate_add_match_subsystem(enumerate, SUBSYSTEM_FILTER);
udev_enumerate_scan_devices(enumerate);
devices = udev_enumerate_get_list_entry(enumerate);
udev_list_entry_foreach(dev_list_entry, devices)
{
struct udev_device *dev;
const char* dev_path = udev_list_entry_get_name(dev_list_entry);
dev = udev_device_new_from_syspath(device, dev_path);
if( true == isDeviceSD(dev) )
{
retVal = true;
udev_device_unref(dev);
break;
}
udev_device_unref(dev);
}
udev_enumerate_unref(enumerate);
return retVal;
}
static void print_device(struct udev_device *device, const char *source)
{
struct timeval tv;
struct timezone tz;
gettimeofday(&tv, &tz);
printf("%-6s[%llu.%06u] %-8s %s (%s)\n",
source,
(unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec,
udev_device_get_action(device),
udev_device_get_devpath(device),
udev_device_get_subsystem(device));
struct udev_list_entry *list_entry;
udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(device))
printf("%s=%s\n",
udev_list_entry_get_name(list_entry),
udev_list_entry_get_value(list_entry));
printf("\n");
}
<----- change event - subsystem block - disk type disk ----->
UDEV [1339412734.522055] change /devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host11/target11:0:0/11:0:0:2/block/sdd (block)
UDEV_LOG=3
ACTION=change
DEVPATH=/devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host11/target11:0:0/11:0:0:2/block/sdd
SUBSYSTEM=block
DEVNAME=/dev/sdd
DEVTYPE=disk
SEQNUM=3168
ID_VENDOR=Generic-
ID_VENDOR_ENC=Generic-
ID_VENDOR_ID=0bda
ID_MODEL=SD_MMC
ID_MODEL_ENC=SD\x2fMMC\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20
ID_MODEL_ID=0151
ID_REVISION=1.00
ID_SERIAL=Generic-_SD_MMC_20060413092100000-0:2
ID_SERIAL_SHORT=20060413092100000
ID_TYPE=disk
ID_INSTANCE=0:2
ID_BUS=usb
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_USB_DRIVER=usb-storage
ID_PATH=pci-0000:02:03.0-usb-0:1:1.0-scsi-0:0:0:2
ID_PART_TABLE_TYPE=dos
UDISKS_PRESENTATION_NOPOLICY=0
UDISKS_PARTITION_TABLE=1
UDISKS_PARTITION_TABLE_SCHEME=mbr
UDISKS_PARTITION_TABLE_COUNT=2
MAJOR=8
MINOR=48
DEVLINKS=/dev/block/8:48 /dev/disk/by-id/usb-Generic-_SD_MMC_20060413092100000-0:2 /dev/disk/by-path/pci-0000:02:03.0-usb-0:1:1.0-scsi-0:0:0:2
<----- add event partition 1 - subsystem block - disk type partition ----->
UDEV [1339412734.719107] add /devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host11/target11:0:0/11:0:0:2/block/sdd/sdd1 (block)
UDEV_LOG=3
ACTION=add
DEVPATH=/devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host11/target11:0:0/11:0:0:2/block/sdd/sdd1
SUBSYSTEM=block
DEVNAME=/dev/sdd1
DEVTYPE=partition
SEQNUM=3169
ID_VENDOR=Generic-
ID_VENDOR_ENC=Generic-
ID_VENDOR_ID=0bda
ID_MODEL=SD_MMC
ID_MODEL_ENC=SD\x2fMMC\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20
ID_MODEL_ID=0151
ID_REVISION=1.00
ID_SERIAL=Generic-_SD_MMC_20060413092100000-0:2
ID_SERIAL_SHORT=20060413092100000
ID_TYPE=disk
ID_INSTANCE=0:2
ID_BUS=usb
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_USB_DRIVER=usb-storage
ID_PATH=pci-0000:02:03.0-usb-0:1:1.0-scsi-0:0:0:2
ID_PART_TABLE_TYPE=dos
ID_FS_UUID=6343c7b9-92a9-4d8f-bdd8-893f1190f294
ID_FS_UUID_ENC=6343c7b9-92a9-4d8f-bdd8-893f1190f294
ID_FS_VERSION=1.0
ID_FS_TYPE=ext2
ID_FS_USAGE=filesystem
UDISKS_PRESENTATION_NOPOLICY=0
UDISKS_PARTITION=1
UDISKS_PARTITION_SCHEME=mbr
UDISKS_PARTITION_NUMBER=1
UDISKS_PARTITION_TYPE=0x83
UDISKS_PARTITION_SIZE=1006919680
UDISKS_PARTITION_SLAVE=/sys/devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host11/target11:0:0/11:0:0:2/block/sdd
UDISKS_PARTITION_OFFSET=11618304
UDISKS_PARTITION_ALIGNMENT_OFFSET=0
MAJOR=8
MINOR=49
DEVLINKS=/dev/block/8:49 /dev/disk/by-id/usb-Generic-_SD_MMC_20060413092100000-0:2-part1 /dev/disk/by-path/pci-0000:02:03.0-usb-0:1:1.0-scsi-0:0:0:2-part1 /dev/disk/by-uuid/6343c7b9-92a9-4d8f-bdd8-893f1190f294
<----- add event partition 2 - subsystem block - disk type partition ----->
UDEV [1339412734.731338] add /devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host11/target11:0:0/11:0:0:2/block/sdd/sdd2 (block)
UDEV_LOG=3
ACTION=add
DEVPATH=/devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host11/target11:0:0/11:0:0:2/block/sdd/sdd2
SUBSYSTEM=block
DEVNAME=/dev/sdd2
DEVTYPE=partition
SEQNUM=3170
ID_VENDOR=Generic-
ID_VENDOR_ENC=Generic-
ID_VENDOR_ID=0bda
ID_MODEL=SD_MMC
ID_MODEL_ENC=SD\x2fMMC\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20
ID_MODEL_ID=0151
ID_REVISION=1.00
ID_SERIAL=Generic-_SD_MMC_20060413092100000-0:2
ID_SERIAL_SHORT=20060413092100000
ID_TYPE=disk
ID_INSTANCE=0:2
ID_BUS=usb
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_USB_DRIVER=usb-storage
ID_PATH=pci-0000:02:03.0-usb-0:1:1.0-scsi-0:0:0:2
ID_PART_TABLE_TYPE=dos
UDISKS_PRESENTATION_NOPOLICY=0
UDISKS_PARTITION=1
UDISKS_PARTITION_SCHEME=mbr
UDISKS_PARTITION_NUMBER=2
UDISKS_PARTITION_TYPE=0xda
UDISKS_PARTITION_SIZE=11618304
UDISKS_PARTITION_FLAGS=boot
UDISKS_PARTITION_SLAVE=/sys/devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host11/target11:0:0/11:0:0:2/block/sdd
UDISKS_PARTITION_OFFSET=1022410752
UDISKS_PARTITION_ALIGNMENT_OFFSET=0
MAJOR=8
MINOR=50
DEVLINKS=/dev/block/8:50 /dev/disk/by-id/usb-Generic-_SD_MMC_20060413092100000-0:2-part2 /dev/disk/by-path/pci-0000:02:03.0-usb-0:1:1.0-scsi-0:0:0:2-part2
从change
事件中,我无法提取有关设备是否已添加或删除的任何信息。我已尝试打开设备名称\dev\sdd
,但我没有权限,因此该选项将被取消
现在我只检查分区的action属性(add
/remove
)
这个版本的程序对于有分区的SD卡非常有效。当没有分区时,只接收change
事件
所以我的问题是:有没有办法检查媒体是否在更改
事件中添加/删除?或者是否有其他方法来检查设备是否可用(请记住分区问题)
任何关于改进设备属性迭代或获取通知方法的建议都将受到欢迎
另外,我不能使用
libusb
:)。好的。所以我让它在没有分区的SD卡PC上工作
更新的代码如下:
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <errno.h>
#include <sys/time.h> //debug -> remove me
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <libudev.h>
#define ADD_FILTER "add"
#define REMOVE_FILTER "remove"
#define SUBSYSTEM_FILTER "block"
#define DEVTYPE_FILTER "disk"
#define ATTR_FILTER "ID_MODEL"
#define SD_ATTR_VALUE "SD_MMC"
#define ATTR_ADDED_DISK "UDISKS_PARTITION_TABLE" // attribute is available for "change" event when SD card is added (n/a when removed)
static bool isDeviceSD(struct udev_device *device); //checks if device is SD card (MMC)
static bool isDevPresent(struct udev *device); //checks if device is present (SD + added)
static bool isDeviceAdded(struct udev_device *device); //checks if device is added (presence of attribute ATTR_ADDED_DISK)
static void print_device(struct udev_device *device, const char *source); //for debugging -> remove me
static bool s_bSD_present;
int main()
{
struct udev *udev;
struct udev_monitor *udev_monitor = NULL;
fd_set readfds;
s_bSD_present = false;
udev = udev_new();
if (udev == NULL)
{
printf("udev_new FAILED \n");
return 1;
}
if( isDevPresent(udev) )
{
s_bSD_present = true;
printf("+++SD is plugged in \n");
}
else
{
printf("---SD is not plugged in \n");
}
udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
if (udev_monitor == NULL) {
printf("udev_monitor_new_from_netlink FAILED \n");
return 1;
}
//add some filters
if( udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, SUBSYSTEM_FILTER, DEVTYPE_FILTER) < 0 )
{
printf("udev_monitor_filter_add_match_subsystem_devtype FAILED \n");
return 1;
}
if (udev_monitor_enable_receiving(udev_monitor) < 0)
{
printf("udev_monitor_enable_receiving FAILED \n");
return 1;
}
while (1) {
printf("Polling for new data... \n");
int fdcount = 0;
FD_ZERO(&readfds);
if (udev_monitor != NULL)
{
FD_SET(udev_monitor_get_fd(udev_monitor), &readfds);
}
fdcount = select(udev_monitor_get_fd(udev_monitor)+1, &readfds, NULL, NULL, NULL);
if (fdcount < 0)
{
if (errno != EINTR)
printf("Error receiving uevent message\n");
continue;
}
if ((udev_monitor != NULL) && FD_ISSET(udev_monitor_get_fd(udev_monitor), &readfds))
{
struct udev_device *device;
device = udev_monitor_receive_device(udev_monitor);
if (device == NULL)
continue;
//check presence
if( isDeviceSD(device) && isDeviceAdded(device) )
{
if(!s_bSD_present) //guard for double "change" events
{
s_bSD_present = true;
printf("+++SD has been plugged in \n");
}
}
else
{
if(s_bSD_present) //not needed -> just keeping consistency
{
s_bSD_present = false;
printf("---SD has been removed \n");
}
}
udev_device_unref(device);
}
}
return 0;
}
static bool isDeviceSD(struct udev_device *device)
{
bool retVal = false;
struct udev_list_entry *list_entry = 0;
struct udev_list_entry* model_entry = 0;
list_entry = udev_device_get_properties_list_entry(device);
model_entry = udev_list_entry_get_by_name(list_entry, ATTR_FILTER);
if( 0 != model_entry )
{
const char* szModelValue = udev_list_entry_get_value(model_entry);
if( strcmp( szModelValue, SD_ATTR_VALUE) == 0 )
{
//printf("Device is SD \n");
retVal = true;
//print_device(device, "UDEV");
}
}
return retVal;
}
static bool isDeviceAdded(struct udev_device *device)
{
bool retVal = false;
struct udev_list_entry *list_entry = 0;
struct udev_list_entry* added_disk_entry = 0;
list_entry = udev_device_get_properties_list_entry(device);
added_disk_entry = udev_list_entry_get_by_name(list_entry,/* "DEVNAME" */ ATTR_ADDED_DISK);
if( 0 != added_disk_entry )
{
retVal = true;
}
return retVal;
}
static bool isDevPresent(struct udev *device)
{
bool retVal = false;
struct udev_enumerate *enumerate;
struct udev_list_entry *devices, *dev_list_entry;
enumerate = udev_enumerate_new(device);
udev_enumerate_add_match_subsystem(enumerate, SUBSYSTEM_FILTER);
udev_enumerate_scan_devices(enumerate);
devices = udev_enumerate_get_list_entry(enumerate);
udev_list_entry_foreach(dev_list_entry, devices)
{
struct udev_device *dev;
const char* dev_path = udev_list_entry_get_name(dev_list_entry);
dev = udev_device_new_from_syspath(device, dev_path);
if( isDeviceSD(dev) && isDeviceAdded(dev) )
{
retVal = true;
udev_device_unref(dev);
break;
}
udev_device_unref(dev);
}
udev_enumerate_unref(enumerate);
return retVal;
}
static void print_device(struct udev_device *device, const char *source)
{
struct timeval tv;
struct timezone tz;
gettimeofday(&tv, &tz);
printf("%-6s[%llu.%06u] %-8s %s (%s)\n",
source,
(unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec,
udev_device_get_action(device),
udev_device_get_devpath(device),
udev_device_get_subsystem(device));
struct udev_list_entry *list_entry;
udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(device))
printf("%s=%s\n",
udev_list_entry_get_name(list_entry),
udev_list_entry_get_value(list_entry));
printf("\n");
}
#包括
#包括
#包括
#包括
#包括
#包括
#包括//调试->删除我
#包括
#包括
#包括
#包括
#定义添加过滤器“添加”
#定义删除过滤器“删除”
#定义子系统过滤器“块”
#定义DEVTYPE_过滤器“磁盘”
#定义属性过滤器“ID\U模型”
#定义SD\U属性值“SD\U MMC”
#定义添加的属性\u磁盘“UDISKS\u分区\u表”//属性在添加SD卡时可用于“更改”事件(删除时不适用)
静态bool isDeviceSD(结构udev_设备*设备)//检查设备是否为SD卡(MMC)
静态bool isDevPresent(结构udev*设备)//检查设备是否存在(SD+已添加)
添加了静态布尔(结构udev_设备*设备)//检查是否添加了设备(是否存在属性ATTR_added_DISK)
静态无效打印设备(结构udev设备*设备,常量字符*源)//用于调试->删除我
静态bool s_bSD_存在;
int main()
{
结构udev*udev;
结构udev_monitor*udev_monitor=NULL;
fd_设置读取FDS;
s_bSD_present=假;
udev=udev_new();
如果(udev==NULL)
{
printf(“udev_new FAILED\n”);
返回1;
}
如果(isDevPresent(udev))
{
s_bSD_present=真;
printf(“+++SD已插入\n”);
}
其他的
{
printf(“--SD未插入\n”);
}
udev_monitor=udev_monitor_new_from_netlink(udev,“udev”);
如果(udev_监视器==NULL){
printf(“udev_monitor_new_from_netlink FAILED\n”);
返回1;
}
//添加一些过滤器
如果(udev_监视器_过滤器_添加_匹配_子系统_开发类型(udev_监视器、子系统_过滤器、开发类型过滤器)<0)
{
printf(“udev_监视器_过滤器_添加_匹配_子系统_devtype失败\n”);
返回1;
}
如果(udev_监视器启用_接收(udev_监视器)<0)
{
printf(“udev\u监视器\u启用\u接收失败\n”);
返回1;
}
而(1){
printf(“轮询新数据…\n”);
int-fdcount=0;
FD_零(&readfds);
如果(udev_监视器!=NULL)
{
FD_设置(udev_监视器_获取_FD(udev_监视器)&读取FDS);
}
fdcount=select(udev_monitor\u get_fd(udev_monitor)+1,&readfds,NULL,NULL,NULL);
如果(fdcount<0)
{
如果(错误号!=EINTR)
printf(“接收uevent消息时出错\n”);
继续;
}
if((udev_监视器!=NULL)和&FD_设置(udev_监视器获取FD(udev_监视器)和&readfds))
{
结构udev_设备*设备;
设备=udev\u监视器\u接收设备(udev\u监视器);
如果(设备==NULL)
继续;
//检查是否存在
if(isDeviceSD(设备)和isDeviceAdded(设备))
{
如果(!s_bSD_present)//保护双重“更改”事件
{
s_bSD_present=真;
printf(“+++SD已插入\n”);
}
}
其他的
{
如果(s_bSD_present)//不需要->保持一致性
{
s_bSD_present=假;
printf(“--SD已被删除\n”);
}
}
udev_装置(装置);;
}
}
返回0;
}
静态bool isDeviceSD(结构udev_设备*设备)
{
bool-retVal=false;
struct udev_list_entry*list_entry=0;
struct udev_list_entry*model_entry=0;
列表项=udev设备获取属性列表项(设备);
model_entry=udev_list_entry_get_by_name(list_entry,ATTR_FILTER);
如果(0!=模型输入)
{
const char*szModelValue=udev_list_entry_get_value(model_entry);
if(strcmp(szModelValue,SD_ATTR_VALUE)==0)
{
//printf(“设备为SD\n”);
retVal=true;
//打印设备(设备“UDEV”);
}
}
返回返回;
}
添加了静态布尔(结构udev_设备*设备)
{
bool-retVal=false;
struct udev_list_entry*list_entry=0;
struct udev_list_entry*added_disk_entry=0;
列表项=udev设备获取属性列表项(设备);
添加的磁盘条目=udev\u列表条目\u按名称获取(列表条目,/*“DEVNAME”*/ATTR\u添加的磁盘);
如果(0!=已添加\u磁盘\u项)
{
retVal=true;
}
返回返回;
}
静态bool isDevPresent(结构udev*设备)
{
bool-retVal=false;
结构udev_枚举*枚举;
结构udev_列表项*设备,*开发列表项;
enumerate=udev_enumerate_new(设备);
udev_枚举子系统添加匹配子系统(枚举子系统过滤器);
udev_枚举扫描_设备(枚举);
发展