#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;
+}
flags |= FD_CLOEXEC;
fcntl(fd, F_SETFD, flags);
}
+
+unsigned int util_crc32(const unsigned char *buf, size_t len)
+{
+ unsigned int crc;
+ const unsigned char *end;
+ static const unsigned int crc32_table[256] = {
+ 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
+ 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
+ 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
+ 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+ 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
+ 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+ 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
+ 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+ 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
+ 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
+ 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
+ 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+ 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
+ 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
+ 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
+ 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+ 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
+ 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+ 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
+ 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+ 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
+ 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
+ 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
+ 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+ 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
+ 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
+ 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
+ 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+ 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
+ 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+ 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
+ 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+ 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
+ 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
+ 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
+ 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+ 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
+ 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
+ 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
+ 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+ 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
+ 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+ 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
+ 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+ 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
+ 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
+ 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
+ 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+ 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
+ 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
+ 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
+ 0x2d02ef8d
+ };
+
+ crc = 0xffffffff;
+ for (end = buf + len; buf < end; ++buf)
+ crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8);
+ return ~crc;
+}
projects / systemd / commitdiff