chiark / gitweb /
[PATCH] use numeric owner/group as default values to avoid parsing userdb
[elogind.git] / udevsend.c
index b26c744..5fe0f45 100644 (file)
 #include <sys/socket.h>
 #include <sys/wait.h>
 #include <sys/un.h>
+#include <time.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>
 #include <string.h>
 #include <unistd.h>
-#include <time.h>
 #include <linux/stddef.h>
 
 #include "udev.h"
 #include "udevd.h"
 #include "logging.h"
 
-unsigned char logname[42];
-
-int log_ok(void)
-{
-       return 1;
-}
+/* global variables */
+static int sock = -1;
 
-static inline char *get_action(void)
+#ifdef LOG
+void log_message (int level, const char *format, ...)
 {
-       char *action;
+       va_list args;
 
-       action = getenv("ACTION");
-       return action;
-}
-
-static inline char *get_devpath(void)
-{
-       char *devpath;
-
-       devpath = getenv("DEVPATH");
-       return devpath;
-}
-
-static inline char *get_seqnum(void)
-{
-       char *seqnum;
-
-       seqnum = getenv("SEQNUM");
-       return seqnum;
-}
-
-static int build_hotplugmsg(struct hotplug_msg *msg, char *action,
-                           char *devpath, char *subsystem, int seqnum)
-{
-       memset(msg, 0x00, sizeof(*msg));
-       strfieldcpy(msg->magic, UDEV_MAGIC);
-       msg->seqnum = seqnum;
-       strncpy(msg->action, action, 8);
-       strncpy(msg->devpath, devpath, 128);
-       strncpy(msg->subsystem, subsystem, 16);
-       return sizeof(struct hotplug_msg);
+       va_start(args, format);
+       vsyslog(level, format, args);
+       va_end(args);
 }
+#endif
 
 static int start_daemon(void)
 {
        pid_t pid;
        pid_t child_pid;
+       char *const argv[] = { "udevd", NULL };
+       char *const envp[] = { NULL };
 
        pid = fork();
        switch (pid) {
@@ -95,12 +68,11 @@ static int start_daemon(void)
                child_pid = fork();
                switch (child_pid) {
                case 0:
-                       /* daemon */
-                       setsid();
-                       chdir("/");
-                       execl(UDEVD_BIN, "udevd", NULL);
+                       /* daemon with empty environment */
+                       close(sock);
+                       execve(UDEVD_BIN, argv, envp);
                        dbg("exec of daemon failed");
-                       exit(1);
+                       _exit(1);
                case -1:
                        dbg("fork of daemon failed");
                        return -1;
@@ -112,133 +84,137 @@ static int start_daemon(void)
                dbg("fork of helper failed");
                return -1;
        default:
-               wait(NULL);
+               waitpid(pid, NULL, 0);
        }
        return 0;
 }
 
-int main(int argc, char* argv[])
+static void run_udev(const char *subsystem)
 {
-       struct hotplug_msg msg;
-       char *action;
-       char *devpath;
-       char *subsystem;
-       char *seqnum;
-       int seq;
-       int retval = 1;
-       int size;
+       char *const argv[] = { "udev", (char *)subsystem, NULL };
+       pid_t pid;
+
+       pid = fork();
+       switch (pid) {
+       case 0:
+               /* child */
+               execv(UDEV_BIN, argv);
+               dbg("exec of child failed");
+               _exit(1);
+               break;
+       case -1:
+               dbg("fork of child failed");
+               break;
+       default:
+               waitpid(pid, NULL, 0);
+       }
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+       static struct udevsend_msg usend_msg;
+       int usend_msg_len;
+       int i;
        int loop;
-       struct timespec tspec;
-       int sock;
        struct sockaddr_un saddr;
        socklen_t addrlen;
+       int bufpos = 0;
+       int retval = 1;
        int started_daemon = 0;
-       struct iovec iov;
-       struct msghdr smsg;
-       char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
-       struct cmsghdr *cmsg;
-       struct ucred *cred;
-       
-
+       const char *subsystem = NULL;
 
-#ifdef DEBUG
-       init_logging("udevsend");
-#endif
-
-       subsystem = argv[1];
-       if (subsystem == NULL) {
-               dbg("no subsystem");
-               goto exit;
-       }
-
-       devpath = get_devpath();
-       if (devpath == NULL) {
-               dbg("no devpath");
-               goto exit;
-       }
-
-       action = get_action();
-       if (action == NULL) {
-               dbg("no action");
-               goto exit;
-       }
-
-       seqnum = get_seqnum();
-       if (seqnum == NULL)
-               seq = -1;
-       else
-               seq = atoi(seqnum);
+       logging_init("udevsend");
+       dbg("version %s", UDEV_VERSION);
 
        sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
        if (sock == -1) {
                dbg("error getting socket");
-               goto exit;
+               goto fallback;
        }
 
-       memset(&saddr, 0x00, sizeof(saddr));
+       memset(&saddr, 0x00, sizeof(struct sockaddr_un));
        saddr.sun_family = AF_LOCAL;
        /* use abstract namespace for socket path */
        strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
        addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 
-       size = build_hotplugmsg(&msg, action, devpath, subsystem, seq);
-
-       /* prepare message with credentials to authenticate ourself */
-       iov.iov_base = &msg;
-       iov.iov_len = size;
-
-       smsg.msg_name = &saddr;
-       smsg.msg_namelen = addrlen;
-       smsg.msg_iov = &iov;
-       smsg.msg_iovlen = 1;
-       smsg.msg_control = cred_msg;
-       smsg.msg_controllen = CMSG_LEN(sizeof(struct ucred));;
-       smsg.msg_flags = 0;
-
-       cmsg = CMSG_FIRSTHDR(&smsg);
-       cmsg->cmsg_level = SOL_SOCKET;
-       cmsg->cmsg_type = SCM_CREDENTIALS;
-       cmsg->cmsg_len = sizeof(cred_msg);
-       cred = (struct ucred *) CMSG_DATA(cmsg);
-       cred->uid = getuid();
-       cred->gid = getgid();
-       cred->pid = getpid();
-       cred->pid = getpid();
+       memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
+       strcpy(usend_msg.magic, UDEV_MAGIC);
+
+       /* copy all keys to send buffer */
+       for (i = 0; envp[i]; i++) {
+               const char *key;
+               int keylen;
+
+               key = envp[i];
+               keylen = strlen(key);
+
+               /* prevent loops in the scripts we execute */
+               if (strncmp(key, "UDEVD_EVENT=", 12) == 0) {
+                       dbg("seems that the event source is not the kernel, just exit");
+                       goto exit;
+               }
+
+               if (bufpos + keylen >= HOTPLUG_BUFFER_SIZE-1) {
+                       dbg("environment buffer too small, probably not called by the kernel");
+                       continue;
+               }
+
+               /* remember the SUBSYSTEM */
+               if (strncmp(key, "SUBSYSTEM=", 10) == 0)
+                       subsystem = &key[10];
+
+               dbg("add '%s' to env[%i] buffer", key, i);
+               strcpy(&usend_msg.envbuf[bufpos], key);
+               bufpos += keylen + 1;
+       }
+       /* older kernels passed the SUBSYSTEM only as the first argument */
+       if (!subsystem && argc == 2) {
+               bufpos += sprintf(&usend_msg.envbuf[bufpos], "SUBSYSTEM=%s", argv[1]) + 1;
+               dbg("add 'SUBSYSTEM=%s' to env[%i] buffer from argv", argv[1], i);
+       }
+
+       usend_msg_len = offsetof(struct udevsend_msg, envbuf) + bufpos;
+       dbg("usend_msg_len=%i", usend_msg_len);
 
        /* If we can't send, try to start daemon and resend message */
-       loop = UDEVSEND_CONNECT_RETRY;
-       while (loop--) {
-               retval = sendmsg(sock, &smsg, 0);
+       loop = SEND_WAIT_MAX_SECONDS * SEND_WAIT_LOOP_PER_SECOND;
+       while (--loop) {
+               retval = sendto(sock, &usend_msg, usend_msg_len, 0, (struct sockaddr *)&saddr, addrlen);
                if (retval != -1) {
                        retval = 0;
-                       goto close_and_exit;
+                       goto exit;
                }
-               
+
                if (errno != ECONNREFUSED) {
-                       dbg("error sending message");
-                       goto close_and_exit;
+                       dbg("error sending message (%s)", strerror(errno));
+                       goto fallback;
                }
-               
+
                if (!started_daemon) {
-                       dbg("connect failed, try starting daemon...");
+                       dbg("try to start udevd daemon");
                        retval = start_daemon();
                        if (retval) {
                                dbg("error starting daemon");
-                               goto exit;
+                               goto fallback;
                        }
-                       
-                       dbg("daemon started");
+                       dbg("udevd daemon started");
                        started_daemon = 1;
                } else {
-                       dbg("retry to connect %d", UDEVSEND_CONNECT_RETRY - loop);
-                       tspec.tv_sec = 0;
-                       tspec.tv_nsec = 100000000;  /* 100 millisec */
-                       nanosleep(&tspec, NULL);
+                       dbg("retry to connect %d", SEND_WAIT_MAX_SECONDS * SEND_WAIT_LOOP_PER_SECOND - loop);
+                       usleep(1000 * 1000 / SEND_WAIT_LOOP_PER_SECOND);
                }
        }
-       
-close_and_exit:
-       close(sock);
+
+fallback:
+       info("unable to connect to event daemon, try to call udev directly");
+       run_udev(subsystem);
+
 exit:
+       if (sock != -1)
+               close(sock);
+
+       logging_close();
+
        return retval;
 }