mirror of
https://github.com/systemd/systemd.git
synced 2025-03-19 22:50:17 +03:00
udevd: listen for netlink events
After the first valid netlink-event all event with a serial number received on the udevsend socket will be ignored. Signed-off-by: Kay Sievers <kay.sievers@suse.de>
This commit is contained in:
Kay Sievers
parent
5e65ab9a19
commit
88f4b6485e
10
udev.c
10
udev.c
@ -54,8 +54,10 @@ void log_message(int priority, const char *format, ...)
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}
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#endif
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/* decide if we should manage the whole hotplug event
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* for now look if the kernel calls udevsend instead of /sbin/hotplug
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/* Decide if we should manage the whole uevent, including multiplexing
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* of the hotplug directories.
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* For now look if the kernel calls udevsend instead of /sbin/hotplug,
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* or the uevent-helper in /proc/sys/kernel/hotplug is empty.
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*/
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static int manage_hotplug_event(void) {
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char helper[256];
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@ -70,13 +72,15 @@ static int manage_hotplug_event(void) {
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if (fd < 0)
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return 0;
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len = read(fd, helper, 256);
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len = read(fd, helper, sizeof(helper)-1);
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close(fd);
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if (len < 0)
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return 0;
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helper[len] = '\0';
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if (helper[0] == '\0' || helper[0] == '\n')
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return 1;
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if (strstr(helper, "udevsend"))
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return 1;
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196
udevd.c
196
udevd.c
@ -38,6 +38,7 @@
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#include <sys/un.h>
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#include <sys/sysinfo.h>
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#include <sys/stat.h>
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#include <linux/netlink.h>
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#include "list.h"
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#include "udev_libc_wrapper.h"
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@ -49,6 +50,7 @@
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/* global variables*/
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static int udevsendsock;
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static int ueventsock;
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static pid_t sid;
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static int pipefds[2];
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@ -126,7 +128,8 @@ static void msg_queue_insert(struct hotplug_msg *msg)
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break;
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if (loop_msg->seqnum == msg->seqnum) {
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info("ignoring duplicate message seq %llu", msg->seqnum);
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dbg("ignoring duplicate message seq %llu", msg->seqnum);
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free(msg);
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return;
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}
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}
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@ -154,6 +157,8 @@ static void execute_udev(struct hotplug_msg *msg)
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switch (pid) {
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case 0:
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/* child */
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if (ueventsock != -1)
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close(ueventsock);
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close(udevsendsock);
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logging_close();
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@ -416,13 +421,60 @@ recheck:
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}
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}
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static struct hotplug_msg *get_msg_from_envbuf(const char *buf, int buf_size)
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{
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int bufpos;
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int i;
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struct hotplug_msg *msg;
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msg = malloc(sizeof(struct hotplug_msg) + buf_size);
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if (msg == NULL)
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return NULL;
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memset(msg, 0x00, sizeof(struct hotplug_msg) + buf_size);
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/* copy environment buffer and reconstruct envp */
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memcpy(msg->envbuf, buf, buf_size);
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bufpos = 0;
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for (i = 0; (bufpos < buf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) {
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int keylen;
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char *key;
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key = &msg->envbuf[bufpos];
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keylen = strlen(key);
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msg->envp[i] = key;
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bufpos += keylen + 1;
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dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
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/* remember some keys for further processing */
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if (strncmp(key, "ACTION=", 7) == 0)
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msg->action = &key[7];
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if (strncmp(key, "DEVPATH=", 8) == 0)
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msg->devpath = &key[8];
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if (strncmp(key, "SUBSYSTEM=", 10) == 0)
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msg->subsystem = &key[10];
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if (strncmp(key, "SEQNUM=", 7) == 0)
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msg->seqnum = strtoull(&key[7], NULL, 10);
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if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
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msg->physdevpath = &key[12];
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if (strncmp(key, "TIMEOUT=", 8) == 0)
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msg->timeout = strtoull(&key[8], NULL, 10);
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}
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msg->envp[i++] = "UDEVD_EVENT=1";
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msg->envp[i] = NULL;
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return msg;
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}
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/* receive the udevsend message and do some sanity checks */
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static struct hotplug_msg *get_udevsend_msg(void)
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{
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static struct udevsend_msg usend_msg;
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struct hotplug_msg *msg;
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int bufpos;
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int i;
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ssize_t size;
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struct msghdr smsg;
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struct cmsghdr *cmsg;
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@ -467,46 +519,60 @@ static struct hotplug_msg *get_udevsend_msg(void)
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envbuf_size = size - offsetof(struct udevsend_msg, envbuf);
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dbg("envbuf_size=%i", envbuf_size);
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msg = malloc(sizeof(struct hotplug_msg) + envbuf_size);
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msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
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if (msg == NULL)
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return NULL;
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memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size);
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return msg;
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}
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/* copy environment buffer and reconstruct envp */
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memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size);
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bufpos = 0;
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for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) {
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int keylen;
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char *key;
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/* receive the kernel user event message and do some sanity checks */
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static struct hotplug_msg *get_uevent_msg(void)
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{
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struct hotplug_msg *msg;
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int bufpos;
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ssize_t size;
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static char buffer[HOTPLUG_BUFFER_SIZE + 512];
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char *pos;
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key = &msg->envbuf[bufpos];
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keylen = strlen(key);
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msg->envp[i] = key;
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bufpos += keylen + 1;
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dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
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/* remember some keys for further processing */
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if (strncmp(key, "ACTION=", 7) == 0)
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msg->action = &key[7];
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if (strncmp(key, "DEVPATH=", 8) == 0)
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msg->devpath = &key[8];
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if (strncmp(key, "SUBSYSTEM=", 10) == 0)
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msg->subsystem = &key[10];
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if (strncmp(key, "SEQNUM=", 7) == 0)
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msg->seqnum = strtoull(&key[7], NULL, 10);
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if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
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msg->physdevpath = &key[12];
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if (strncmp(key, "TIMEOUT=", 8) == 0)
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msg->timeout = strtoull(&key[8], NULL, 10);
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size = recv(ueventsock, &buffer, sizeof(buffer), 0);
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if (size < 0) {
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if (errno != EINTR)
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dbg("unable to receive udevsend message");
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return NULL;
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}
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if ((size_t)size > sizeof(buffer)-1)
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size = sizeof(buffer)-1;
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buffer[size] = '\0';
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dbg("uevent_size=%i", size);
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/* start of event payload */
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bufpos = strlen(buffer)+1;
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msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
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if (msg == NULL)
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return NULL;
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/* validate message */
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pos = strchr(buffer, '@');
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if (pos == NULL) {
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dbg("invalid uevent '%s'", buffer);
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free(msg);
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return NULL;
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}
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pos[0] = '\0';
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if (msg->action == NULL) {
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dbg("no ACTION in payload found, skip event '%s'", buffer);
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free(msg);
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return NULL;
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}
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if (strcmp(msg->action, buffer) != 0) {
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dbg("ACTION in payload does not match uevent, skip event '%s'", buffer);
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free(msg);
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return NULL;
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}
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msg->envp[i++] = "UDEVD_EVENT=1";
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msg->envp[i] = NULL;
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return msg;
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}
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@ -622,6 +688,34 @@ static int init_udevsend_socket(void)
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return 0;
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}
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static int init_uevent_socket(void)
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{
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struct sockaddr_nl snl;
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int retval;
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memset(&snl, 0x00, sizeof(struct sockaddr_nl));
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snl.nl_family = AF_NETLINK;
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snl.nl_pid = getpid();
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snl.nl_groups = 0xffffffff;
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ueventsock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
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if (ueventsock == -1) {
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dbg("error getting socket, %s", strerror(errno));
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return -1;
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}
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retval = bind(ueventsock, (struct sockaddr *) &snl,
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sizeof(struct sockaddr_nl));
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if (retval < 0) {
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dbg("bind failed, %s", strerror(errno));
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close(ueventsock);
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ueventsock = -1;
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return -1;
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}
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return 0;
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}
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int main(int argc, char *argv[], char *envp[])
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{
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struct sysinfo info;
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@ -631,6 +725,7 @@ int main(int argc, char *argv[], char *envp[])
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struct sigaction act;
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fd_set readfds;
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const char *udevd_expected_seqnum;
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int uevent_active = 0;
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logging_init("udevd");
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udev_init_config();
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@ -716,6 +811,10 @@ int main(int argc, char *argv[], char *envp[])
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sigaction(SIGALRM, &act, NULL);
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sigaction(SIGCHLD, &act, NULL);
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if (init_uevent_socket() < 0) {
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dbg("uevent socket not available");
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}
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if (init_udevsend_socket() < 0) {
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if (errno == EADDRINUSE)
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dbg("another udevd running, exit");
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@ -745,6 +844,8 @@ int main(int argc, char *argv[], char *envp[])
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FD_ZERO(&readfds);
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FD_SET(udevsendsock, &readfds);
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if (ueventsock != -1)
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FD_SET(ueventsock, &readfds);
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FD_SET(pipefds[0], &readfds);
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maxsockplus = udevsendsock+1;
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while (1) {
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@ -761,8 +862,27 @@ int main(int argc, char *argv[], char *envp[])
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if (FD_ISSET(udevsendsock, &workreadfds)) {
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msg = get_udevsend_msg();
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if (msg)
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if (msg) {
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/* discard kernel messages if netlink is active */
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if (uevent_active && msg->seqnum != 0) {
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dbg("skip kernel udevsend message, netlink is active");
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free(msg);
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continue;
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}
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msg_queue_insert(msg);
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}
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}
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if (FD_ISSET(ueventsock, &workreadfds)) {
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msg = get_uevent_msg();
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if (msg) {
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msg_queue_insert(msg);
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/* disable udevsend with first netlink message */
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if (!uevent_active) {
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info("netlink message received, disable kernel udevsend messages");
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uevent_active = 1;
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}
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}
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}
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if (FD_ISSET(pipefds[0], &workreadfds))
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