#include <errno.h>
#include <string.h>
#include <dirent.h>
+#include <sys/poll.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
+#include <arpa/inet.h>
#include <linux/netlink.h>
+#include <linux/filter.h>
#include "libudev.h"
#include "libudev-private.h"
struct sockaddr_nl snl_peer;
struct sockaddr_un sun;
socklen_t addrlen;
+ struct udev_list_node filter_subsystem_list;
};
enum udev_monitor_netlink_group {
UDEV_MONITOR_UDEV = 2,
};
+#define UDEV_MONITOR_MAGIC 0xcafe1dea
+struct udev_monitor_netlink_header {
+ /* udev version text */
+ char version[16];
+ /*
+ * magic to protect against daemon <-> library message format mismatch
+ * used in the kernel from socket filter rules; needs to be stored in network order
+ */
+ unsigned int magic;
+ /* properties buffer */
+ unsigned short properties_off;
+ unsigned short properties_len;
+ /*
+ * crc32 of some common device properties to filter with socket filters in the client
+ * used in the kernel from socket filter rules; needs to be stored in network order
+ */
+ unsigned int filter_subsystem;
+};
+
+static struct udev_monitor *udev_monitor_new(struct udev *udev)
+{
+ struct udev_monitor *udev_monitor;
+
+ udev_monitor = calloc(1, sizeof(struct udev_monitor));
+ if (udev_monitor == NULL)
+ return NULL;
+ udev_monitor->refcount = 1;
+ udev_monitor->udev = udev;
+ udev_list_init(&udev_monitor->filter_subsystem_list);
+ return udev_monitor;
+}
+
/**
* udev_monitor_new_from_socket:
* @udev: udev library context
return NULL;
if (socket_path == NULL)
return NULL;
- udev_monitor = calloc(1, sizeof(struct udev_monitor));
+ udev_monitor = udev_monitor_new(udev);
if (udev_monitor == NULL)
return NULL;
- udev_monitor->refcount = 1;
- udev_monitor->udev = udev;
udev_monitor->sun.sun_family = AF_LOCAL;
if (socket_path[0] == '@') {
else
return NULL;
- udev_monitor = calloc(1, sizeof(struct udev_monitor));
+ udev_monitor = udev_monitor_new(udev);
if (udev_monitor == NULL)
return NULL;
- udev_monitor->refcount = 1;
- udev_monitor->udev = udev;
udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
if (udev_monitor->sock == -1) {
return udev_monitor;
}
+static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i,
+ unsigned short code, unsigned int data)
+{
+ struct sock_filter *ins = &inss[*i];
+
+ ins->code = code;
+ ins->k = data;
+ (*i)++;
+}
+
+static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i,
+ unsigned short code, unsigned int data,
+ unsigned short jt, unsigned short jf)
+{
+ struct sock_filter *ins = &inss[*i];
+
+ ins->code = code;
+ ins->jt = jt;
+ ins->jf = jf;
+ ins->k = data;
+ (*i)++;
+}
+
+static int filter_apply(struct udev_monitor *udev_monitor)
+{
+ static struct sock_filter ins[256];
+ static struct sock_fprog filter;
+ unsigned int i;
+ struct udev_list_entry *list_entry;
+ int err;
+
+ if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL)
+ return 0;
+
+ memset(ins, 0x00, sizeof(ins));
+ i = 0;
+
+ /* load magic in accu */
+ bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic));
+ /* jump if magic matches */
+ bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0);
+ /* wrong magic, drop packet */
+ bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
+
+ /* load filter_subsystem value in accu */
+ bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem));
+ /* add all subsystem match values */
+ udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) {
+ const char *subsys = udev_list_entry_get_name(list_entry);
+ unsigned int crc;
+
+ crc = util_crc32((unsigned char *)subsys, strlen(subsys));
+ /* jump if value does not match */
+ bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, crc, 0, 1);
+ /* matched, pass packet */
+ bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
+
+ if (i+1 >= ARRAY_SIZE(ins))
+ return -1;
+ }
+ /* nothing matched, drop packet */
+ bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
+
+ /* install filter */
+ filter.len = i;
+ filter.filter = ins;
+ err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));
+ return err;
+}
+
int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
{
int err;
const int on = 1;
- if (udev_monitor->sun.sun_family != 0)
+ if (udev_monitor->sun.sun_family != 0) {
err = bind(udev_monitor->sock,
(struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
- else if (udev_monitor->snl.nl_family != 0)
+ } else if (udev_monitor->snl.nl_family != 0) {
+ filter_apply(udev_monitor);
err = bind(udev_monitor->sock,
(struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
- else
+ } else {
return -EINVAL;
+ }
if (err < 0) {
err(udev_monitor->udev, "bind failed: %m\n");
return;
if (udev_monitor->sock >= 0)
close(udev_monitor->sock);
+ udev_list_cleanup_entries(udev_monitor->udev, &udev_monitor->filter_subsystem_list);
dbg(udev_monitor->udev, "monitor %p released\n", udev_monitor);
free(udev_monitor);
}
return udev_monitor->sock;
}
+static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device)
+{
+ struct udev_list_entry *list_entry;
+ int pass = 0;
+
+ if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL)
+ return 1;
+
+ udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) {
+ const char *subsys = udev_device_get_subsystem(udev_device);
+
+ if (strcmp(udev_list_entry_get_name(list_entry), subsys) == 0) {
+ pass= 1;
+ break;
+ }
+ }
+ return pass;
+}
+
/**
* udev_monitor_receive_device:
* @udev_monitor: udev monitor
struct ucred *cred;
char buf[4096];
size_t bufpos;
+ struct udev_monitor_netlink_header *nlh;
int devpath_set = 0;
int subsystem_set = 0;
int action_set = 0;
int maj = 0;
int min = 0;
+retry:
if (udev_monitor == NULL)
return NULL;
memset(buf, 0x00, sizeof(buf));
if (udev_monitor->snl.nl_family != 0) {
smsg.msg_name = &snl;
- smsg.msg_namelen = sizeof snl;
+ smsg.msg_namelen = sizeof(snl);
}
if (recvmsg(udev_monitor->sock, &smsg, 0) < 0) {
return NULL;
}
- /* skip header */
- bufpos = strlen(buf) + 1;
- if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
- info(udev_monitor->udev, "invalid message length\n");
- return NULL;
- }
+ nlh = (struct udev_monitor_netlink_header *) buf;
+ if (nlh->magic == ntohl(UDEV_MONITOR_MAGIC)) {
+ /* udev message with version magic */
+ if (nlh->properties_off < sizeof(struct udev_monitor_netlink_header))
+ return NULL;
+ if (nlh->properties_off+32U > sizeof(buf))
+ return NULL;
+ bufpos = nlh->properties_off;
+ } else {
+ /* kernel message with header */
+ bufpos = strlen(buf) + 1;
+ if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
+ info(udev_monitor->udev, "invalid message length\n");
+ return NULL;
+ }
- /* check message header */
- if (strstr(buf, "@/") == NULL) {
- info(udev_monitor->udev, "unrecognized message header\n");
- return NULL;
+ /* check message header */
+ if (strstr(buf, "@/") == NULL) {
+ info(udev_monitor->udev, "unrecognized message header\n");
+ return NULL;
+ }
}
udev_device = device_new(udev_monitor->udev);
udev_device_unref(udev_device);
return NULL;
}
+
+ /* skip device, if it does not pass the current filter */
+ if (!passes_filter(udev_monitor, udev_device)) {
+ struct pollfd pfd[1];
+ int rc;
+
+ udev_device_unref(udev_device);
+
+ /* if something is queued, get next device */
+ pfd[0].fd = udev_monitor->sock;
+ pfd[0].events = POLLIN;
+ rc = poll(pfd, 1, 0);
+ if (rc > 0)
+ goto retry;
+ return NULL;
+ }
+
if (maj > 0)
udev_device_set_devnum(udev_device, makedev(maj, min));
udev_device_set_info_loaded(udev_device);
int udev_monitor_send_device(struct udev_monitor *udev_monitor, struct udev_device *udev_device)
{
+ struct msghdr smsg;
+ struct iovec iov[2];
const char *buf;
- ssize_t len;
+ ssize_t blen;
ssize_t count;
- len = udev_device_get_properties_monitor_buf(udev_device, &buf);
- if (len < 32)
+ blen = udev_device_get_properties_monitor_buf(udev_device, &buf);
+ if (blen < 32)
return -1;
- if (udev_monitor->sun.sun_family != 0)
- count = sendto(udev_monitor->sock,
- buf, len, 0,
- (struct sockaddr *)&udev_monitor->sun,
- udev_monitor->addrlen);
- else if (udev_monitor->snl.nl_family != 0)
+
+ if (udev_monitor->sun.sun_family != 0) {
+ const char *action;
+ char header[2048];
+ size_t hlen;
+
+ /* header <action>@<devpath> */
+ action = udev_device_get_action(udev_device);
+ if (action == NULL)
+ return -EINVAL;
+ util_strlcpy(header, action, sizeof(header));
+ util_strlcat(header, "@", sizeof(header));
+ hlen = util_strlcat(header, udev_device_get_devpath(udev_device), sizeof(header))+1;
+ if (hlen >= sizeof(header))
+ return -EINVAL;
+ iov[0].iov_base = header;
+ iov[0].iov_len = hlen;
+
+ /* add properties list */
+ iov[1].iov_base = (char *)buf;
+ iov[1].iov_len = blen;
+
+ memset(&smsg, 0x00, sizeof(struct msghdr));
+ smsg.msg_iov = iov;
+ smsg.msg_iovlen = 2;
+ smsg.msg_name = &udev_monitor->sun;
+ smsg.msg_namelen = udev_monitor->addrlen;
+ } else if (udev_monitor->snl.nl_family != 0) {
+ const char *val;
+ size_t vlen;
+ struct udev_monitor_netlink_header nlh;
+
+
+ /* add versioned header */
+ memset(&nlh, 0x00, sizeof(struct udev_monitor_netlink_header));
+ util_strlcpy(nlh.version, "udev-" VERSION, sizeof(nlh.version));
+ nlh.magic = htonl(UDEV_MONITOR_MAGIC);
+ val = udev_device_get_subsystem(udev_device);
+ vlen = strlen(val);
+ nlh.filter_subsystem = htonl(util_crc32((unsigned char *)val, vlen));
+ iov[0].iov_base = &nlh;
+ iov[0].iov_len = sizeof(struct udev_monitor_netlink_header);
+
+ /* add properties list */
+ nlh.properties_off = iov[0].iov_len;
+ nlh.properties_len = blen;
+ iov[1].iov_base = (char *)buf;
+ iov[1].iov_len = blen;
+
+ memset(&smsg, 0x00, sizeof(struct msghdr));
+ smsg.msg_iov = iov;
+ smsg.msg_iovlen = 2;
/* no destination besides the muticast group, we will always get ECONNREFUSED */
- count = sendto(udev_monitor->sock,
- buf, len, 0,
- (struct sockaddr *)&udev_monitor->snl_peer,
- sizeof(struct sockaddr_nl));
- else
+ smsg.msg_name = &udev_monitor->snl_peer;
+ smsg.msg_namelen = sizeof(struct sockaddr_nl);
+ } else {
return -1;
+ }
+ count = sendmsg(udev_monitor->sock, &smsg, 0);
info(udev_monitor->udev, "passed %zi bytes to monitor %p\n", count, udev_monitor);
return count;
}
+
+int udev_monitor_filter_add_match_subsystem(struct udev_monitor *udev_monitor, const char *subsystem)
+{
+ if (udev_monitor == NULL)
+ return -EINVAL;
+ if (subsystem == NULL)
+ return 0;
+ if (udev_list_entry_add(udev_monitor->udev,
+ &udev_monitor->filter_subsystem_list, subsystem, NULL, 1, 0) == NULL)
+ return -ENOMEM;
+ return 0;
+}
~ianmdlvl / elogind.git / blobdiff