[PATCH] Provide access to git_dir through get_git_dir().
[git.git] / daemon.c
index 3219615..fe46d3e 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -3,15 +3,80 @@
 #include <signal.h>
 #include <sys/wait.h>
 #include <sys/socket.h>
+#include <sys/time.h>
+#include <netdb.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
+#include <syslog.h>
+
+static int log_syslog;
+static int verbose;
+
+static const char daemon_usage[] = "git-daemon [--verbose] [--syslog] [--inetd | --port=n]";
+
+
+static void logreport(int priority, const char *err, va_list params)
+{
+       /* We should do a single write so that it is atomic and output
+        * of several processes do not get intermingled. */
+       char buf[1024];
+       int buflen;
+       int maxlen, msglen;
+
+       /* sizeof(buf) should be big enough for "[pid] \n" */
+       buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
+
+       maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
+       msglen = vsnprintf(buf + buflen, maxlen, err, params);
+
+       if (log_syslog) {
+               syslog(priority, "%s", buf);
+               return;
+       }
+
+       /* maxlen counted our own LF but also counts space given to
+        * vsnprintf for the terminating NUL.  We want to make sure that
+        * we have space for our own LF and NUL after the "meat" of the
+        * message, so truncate it at maxlen - 1.
+        */
+       if (msglen > maxlen - 1)
+               msglen = maxlen - 1;
+       else if (msglen < 0)
+               msglen = 0; /* Protect against weird return values. */
+       buflen += msglen;
+
+       buf[buflen++] = '\n';
+       buf[buflen] = '\0';
+
+       write(2, buf, buflen);
+}
+
+void logerror(const char *err, ...)
+{
+       va_list params;
+       va_start(params, err);
+       logreport(LOG_ERR, err, params);
+       va_end(params);
+}
+
+void loginfo(const char *err, ...)
+{
+       va_list params;
+       if (!verbose)
+               return;
+       va_start(params, err);
+       logreport(LOG_INFO, err, params);
+       va_end(params);
+}
 
-static const char daemon_usage[] = "git-daemon [--inetd | --port=n]";
 
 static int upload(char *dir, int dirlen)
 {
-       if (chdir(dir) < 0)
+       loginfo("Request for '%s'", dir);
+       if (chdir(dir) < 0) {
+               logerror("Cannot chdir('%s'): %s", dir, strerror(errno));
                return -1;
+       }
        chdir(".git");
 
        /*
@@ -23,8 +88,16 @@ static int upload(char *dir, int dirlen)
         */
        if (access("git-daemon-export-ok", F_OK) ||
            access("objects/00", X_OK) ||
-           access("HEAD", R_OK))
+           access("HEAD", R_OK)) {
+               logerror("Not a valid gitd-enabled repository: '%s'", dir);
                return -1;
+       }
+
+       /*
+        * We'll ignore SIGTERM from now on, we have a
+        * good client.
+        */
+       signal(SIGTERM, SIG_IGN);
 
        /* git-upload-pack only ever reads stuff, so this is safe */
        execlp("git-upload-pack", "git-upload-pack", ".", NULL);
@@ -44,7 +117,7 @@ static int execute(void)
        if (!strncmp("git-upload-pack /", line, 17))
                return upload(line + 16, len - 16);
 
-       fprintf(stderr, "got bad connection '%s'\n", line);
+       logerror("Protocol error: '%s'", line);
        return -1;
 }
 
@@ -65,23 +138,23 @@ static int max_connections = 25;
 
 /* These are updated by the signal handler */
 static volatile unsigned int children_reaped = 0;
-pid_t dead_child[MAX_CHILDREN];
+static pid_t dead_child[MAX_CHILDREN];
 
 /* These are updated by the main loop */
 static unsigned int children_spawned = 0;
 static unsigned int children_deleted = 0;
 
-struct child {
+static struct child {
        pid_t pid;
        int addrlen;
-       struct sockaddr_in address;
+       struct sockaddr_storage address;
 } live_child[MAX_CHILDREN];
 
-static void add_child(int idx, pid_t pid, struct sockaddr_in *addr, int addrlen)
+static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
 {
        live_child[idx].pid = pid;
        live_child[idx].addrlen = addrlen;
-       live_child[idx].address = *addr;
+       memcpy(&live_child[idx].address, addr, addrlen);
 }
 
 /*
@@ -128,33 +201,24 @@ static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
  *
  * Really, this is just a place-holder for a _real_ algorithm.
  */
-static void kill_some_children(int connections, unsigned start, unsigned stop)
+static void kill_some_children(int signo, unsigned start, unsigned stop)
 {
        start %= MAX_CHILDREN;
        stop %= MAX_CHILDREN;
        while (start != stop) {
                if (!(start & 3))
-                       kill(live_child[start].pid, SIGTERM);
+                       kill(live_child[start].pid, signo);
                start = (start + 1) % MAX_CHILDREN;
        }
 }
 
-static void handle(int incoming, struct sockaddr_in *addr, int addrlen)
+static void check_max_connections(void)
 {
-       pid_t pid = fork();
-
-       if (pid) {
+       for (;;) {
                int active;
                unsigned spawned, reaped, deleted;
 
-               close(incoming);
-               if (pid < 0)
-                       return;
-
                spawned = children_spawned;
-               add_child(spawned % MAX_CHILDREN, pid, addr, addrlen);
-               children_spawned = ++spawned;
-
                reaped = children_reaped;
                deleted = children_deleted;
 
@@ -166,33 +230,85 @@ static void handle(int incoming, struct sockaddr_in *addr, int addrlen)
                children_deleted = deleted;
 
                active = spawned - deleted;
-               if (active > max_connections) {
-                       kill_some_children(active, deleted, spawned);
+               if (active <= max_connections)
+                       break;
 
-                       /* Wait to make sure they're gone */
-                       while (spawned - children_reaped > max_connections)
-                               sleep(1);
-               }
-                       
+               /* Kill some unstarted connections with SIGTERM */
+               kill_some_children(SIGTERM, deleted, spawned);
+               if (active <= max_connections << 1)
+                       break;
+
+               /* If the SIGTERM thing isn't helping use SIGKILL */
+               kill_some_children(SIGKILL, deleted, spawned);
+               sleep(1);
+       }
+}
+
+static void handle(int incoming, struct sockaddr *addr, int addrlen)
+{
+       pid_t pid = fork();
+       char addrbuf[256] = "";
+       int port = -1;
 
+       if (pid) {
+               unsigned idx;
+
+               close(incoming);
+               if (pid < 0)
+                       return;
+
+               idx = children_spawned % MAX_CHILDREN;
+               children_spawned++;
+               add_child(idx, pid, addr, addrlen);
+
+               check_max_connections();
                return;
        }
 
        dup2(incoming, 0);
        dup2(incoming, 1);
        close(incoming);
+
+       if (addr->sa_family == AF_INET) {
+               struct sockaddr_in *sin_addr = (void *) addr;
+               inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
+               port = sin_addr->sin_port;
+
+       } else if (addr->sa_family == AF_INET6) {
+               struct sockaddr_in6 *sin6_addr = (void *) addr;
+
+               char *buf = addrbuf;
+               *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
+               inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
+               strcat(buf, "]");
+
+               port = sin6_addr->sin6_port;
+       }
+       loginfo("Connection from %s:%d", addrbuf, port);
+
        exit(execute());
 }
 
 static void child_handler(int signo)
 {
        for (;;) {
-               pid_t pid = waitpid(-1, NULL, WNOHANG);
+               int status;
+               pid_t pid = waitpid(-1, &status, WNOHANG);
 
                if (pid > 0) {
                        unsigned reaped = children_reaped;
                        dead_child[reaped % MAX_CHILDREN] = pid;
                        children_reaped = reaped + 1;
+                       /* XXX: Custom logging, since we don't wanna getpid() */
+                       if (verbose) {
+                               char *dead = "";
+                               if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
+                                       dead = " (with error)";
+                               if (log_syslog)
+                                       syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
+                               else
+                                       fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
+                       }
                        continue;
                }
                break;
@@ -201,37 +317,109 @@ static void child_handler(int signo)
 
 static int serve(int port)
 {
-       int sockfd;
-       struct sockaddr_in addr;
+       struct addrinfo hints, *ai0, *ai;
+       int gai;
+       int socknum = 0, *socklist = NULL;
+       int maxfd = -1;
+       fd_set fds_init, fds;
+       char pbuf[NI_MAXSERV];
 
        signal(SIGCHLD, child_handler);
-       sockfd = socket(PF_INET, SOCK_STREAM, IPPROTO_IP);
-       if (sockfd < 0)
-               die("unable to open socket (%s)", strerror(errno));
-       memset(&addr, 0, sizeof(addr));
-       addr.sin_port = htons(port);
-       addr.sin_family = AF_INET;
-       if (bind(sockfd, (void *)&addr, sizeof(addr)) < 0)
-               die("unable to bind to port %d (%s)", port, strerror(errno));
-       if (listen(sockfd, 5) < 0)
-               die("unable to listen to port %d (%s)", port, strerror(errno));
+
+       sprintf(pbuf, "%d", port);
+       memset(&hints, 0, sizeof(hints));
+       hints.ai_family = AF_UNSPEC;
+       hints.ai_socktype = SOCK_STREAM;
+       hints.ai_protocol = IPPROTO_TCP;
+       hints.ai_flags = AI_PASSIVE;
+
+       gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
+       if (gai)
+               die("getaddrinfo() failed: %s\n", gai_strerror(gai));
+
+       FD_ZERO(&fds_init);
+
+       for (ai = ai0; ai; ai = ai->ai_next) {
+               int sockfd;
+               int *newlist;
+
+               sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+               if (sockfd < 0)
+                       continue;
+               if (sockfd >= FD_SETSIZE) {
+                       error("too large socket descriptor.");
+                       close(sockfd);
+                       continue;
+               }
+
+#ifdef IPV6_V6ONLY
+               if (ai->ai_family == AF_INET6) {
+                       int on = 1;
+                       setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
+                                  &on, sizeof(on));
+                       /* Note: error is not fatal */
+               }
+#endif
+
+               if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
+                       close(sockfd);
+                       continue;       /* not fatal */
+               }
+               if (listen(sockfd, 5) < 0) {
+                       close(sockfd);
+                       continue;       /* not fatal */
+               }
+
+               newlist = realloc(socklist, sizeof(int) * (socknum + 1));
+               if (!newlist)
+                       die("memory allocation failed: %s", strerror(errno));
+
+               socklist = newlist;
+               socklist[socknum++] = sockfd;
+
+               FD_SET(sockfd, &fds_init);
+               if (maxfd < sockfd)
+                       maxfd = sockfd;
+       }
+
+       freeaddrinfo(ai0);
+
+       if (socknum == 0)
+               die("unable to allocate any listen sockets on port %u", port);
 
        for (;;) {
-               struct sockaddr_in in;
-               socklen_t addrlen = sizeof(in);
-               int incoming = accept(sockfd, (void *)&in, &addrlen);
-
-               if (incoming < 0) {
-                       switch (errno) {
-                       case EAGAIN:
-                       case EINTR:
-                       case ECONNABORTED:
-                               continue;
-                       default:
-                               die("accept returned %s", strerror(errno));
+               int i;
+               fds = fds_init;
+               
+               if (select(maxfd + 1, &fds, NULL, NULL, NULL) < 0) {
+                       if (errno != EINTR) {
+                               error("select failed, resuming: %s",
+                                     strerror(errno));
+                               sleep(1);
+                       }
+                       continue;
+               }
+
+               for (i = 0; i < socknum; i++) {
+                       int sockfd = socklist[i];
+
+                       if (FD_ISSET(sockfd, &fds)) {
+                               struct sockaddr_storage ss;
+                               int sslen = sizeof(ss);
+                               int incoming = accept(sockfd, (struct sockaddr *)&ss, &sslen);
+                               if (incoming < 0) {
+                                       switch (errno) {
+                                       case EAGAIN:
+                                       case EINTR:
+                                       case ECONNABORTED:
+                                               continue;
+                                       default:
+                                               die("accept returned %s", strerror(errno));
+                                       }
+                               }
+                               handle(incoming, (struct sockaddr *)&ss, sslen);
                        }
                }
-               handle(incoming, &in, addrlen);
        }
 }
 
@@ -258,12 +446,23 @@ int main(int argc, char **argv)
                        inetd_mode = 1;
                        continue;
                }
+               if (!strcmp(arg, "--verbose")) {
+                       verbose = 1;
+                       continue;
+               }
+               if (!strcmp(arg, "--syslog")) {
+                       log_syslog = 1;
+                       openlog("git-daemon", 0, LOG_DAEMON);
+                       continue;
+               }
 
                usage(daemon_usage);
        }
 
-       if (inetd_mode)
+       if (inetd_mode) {
+               fclose(stderr); //FIXME: workaround
                return execute();
+       }
 
        return serve(port);
 }