Merge branch 'cr/remote-update-v'
[gitweb.git] / daemon.c
index 8dcde73200d1ddbc0dec0dbfdc2f4ff15047abd9..1cef3098d2bd2fb28e2b670ac26c41eebf37dc78 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -1,7 +1,6 @@
 #include "cache.h"
 #include "pkt-line.h"
 #include "exec_cmd.h"
-#include "interpolate.h"
 
 #include <syslog.h>
 
 static int log_syslog;
 static int verbose;
 static int reuseaddr;
-static int child_handler_pipe[2];
 
 static const char daemon_usage[] =
 "git daemon [--verbose] [--syslog] [--export-all]\n"
-"           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
-"           [--base-path=path] [--base-path-relaxed]\n"
+"           [--timeout=n] [--init-timeout=n] [--max-connections=n]\n"
+"           [--strict-paths] [--base-path=path] [--base-path-relaxed]\n"
 "           [--user-path | --user-path=path]\n"
 "           [--interpolated-path=path]\n"
 "           [--reuseaddr] [--detach] [--pid-file=file]\n"
@@ -55,61 +53,26 @@ static const char *user_path;
 static unsigned int timeout;
 static unsigned int init_timeout;
 
-/*
- * Static table for now.  Ugh.
- * Feel free to make dynamic as needed.
- */
-#define INTERP_SLOT_HOST       (0)
-#define INTERP_SLOT_CANON_HOST (1)
-#define INTERP_SLOT_IP         (2)
-#define INTERP_SLOT_PORT       (3)
-#define INTERP_SLOT_DIR                (4)
-#define INTERP_SLOT_PERCENT    (5)
-
-static struct interp interp_table[] = {
-       { "%H", 0},
-       { "%CH", 0},
-       { "%IP", 0},
-       { "%P", 0},
-       { "%D", 0},
-       { "%%", 0},
-};
-
+static char *hostname;
+static char *canon_hostname;
+static char *ip_address;
+static char *tcp_port;
 
 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) {
+               char buf[1024];
+               vsnprintf(buf, sizeof(buf), err, params);
                syslog(priority, "%s", buf);
-               return;
+       } else {
+               /*
+                * Since stderr is set to linebuffered mode, the
+                * logging of different processes will not overlap
+                */
+               fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
+               vfprintf(stderr, err, params);
+               fputc('\n', stderr);
        }
-
-       /* 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_in_full(2, buf, buflen);
 }
 
 static void logerror(const char *err, ...)
@@ -183,7 +146,7 @@ static int avoid_alias(char *p)
        }
 }
 
-static char *path_ok(struct interp *itable)
+static char *path_ok(char *directory)
 {
        static char rpath[PATH_MAX];
        static char interp_path[PATH_MAX];
@@ -191,7 +154,7 @@ static char *path_ok(struct interp *itable)
        char *path;
        char *dir;
 
-       dir = itable[INTERP_SLOT_DIR].value;
+       dir = directory;
 
        if (avoid_alias(dir)) {
                logerror("'%s': aliased", dir);
@@ -221,14 +184,27 @@ static char *path_ok(struct interp *itable)
                }
        }
        else if (interpolated_path && saw_extended_args) {
+               struct strbuf expanded_path = STRBUF_INIT;
+               struct strbuf_expand_dict_entry dict[] = {
+                       { "H", hostname },
+                       { "CH", canon_hostname },
+                       { "IP", ip_address },
+                       { "P", tcp_port },
+                       { "D", directory },
+                       { "%", "%" },
+                       { NULL }
+               };
+
                if (*dir != '/') {
                        /* Allow only absolute */
                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
                        return NULL;
                }
 
-               interpolate(interp_path, PATH_MAX, interpolated_path,
-                           interp_table, ARRAY_SIZE(interp_table));
+               strbuf_expand(&expanded_path, interpolated_path,
+                               strbuf_expand_dict_cb, &dict);
+               strlcpy(interp_path, expanded_path.buf, PATH_MAX);
+               strbuf_release(&expanded_path);
                loginfo("Interpolated dir '%s'", interp_path);
 
                dir = interp_path;
@@ -253,7 +229,7 @@ static char *path_ok(struct interp *itable)
                 * prefixing the base path
                 */
                if (base_path && base_path_relaxed && !retried_path) {
-                       dir = itable[INTERP_SLOT_DIR].value;
+                       dir = directory;
                        retried_path = 1;
                        continue;
                }
@@ -319,14 +295,12 @@ static int git_daemon_config(const char *var, const char *value, void *cb)
        return 0;
 }
 
-static int run_service(struct interp *itable, struct daemon_service *service)
+static int run_service(char *dir, struct daemon_service *service)
 {
        const char *path;
        int enabled = service->enabled;
 
-       loginfo("Request %s for '%s'",
-               service->name,
-               itable[INTERP_SLOT_DIR].value);
+       loginfo("Request %s for '%s'", service->name, dir);
 
        if (!enabled && !service->overridable) {
                logerror("'%s': service not enabled.", service->name);
@@ -334,7 +308,7 @@ static int run_service(struct interp *itable, struct daemon_service *service)
                return -1;
        }
 
-       if (!(path = path_ok(itable)))
+       if (!(path = path_ok(dir)))
                return -1;
 
        /*
@@ -433,13 +407,13 @@ static void make_service_overridable(const char *name, int ena)
 
 /*
  * Separate the "extra args" information as supplied by the client connection.
- * Any resulting data is squirreled away in the given interpolation table.
  */
-static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
+static void parse_extra_args(char *extra_args, int buflen)
 {
        char *val;
        int vallen;
        char *end = extra_args + buflen;
+       char *hp;
 
        while (extra_args < end && *extra_args) {
                saw_extended_args = 1;
@@ -453,25 +427,22 @@ static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
                                if (port) {
                                        *port = 0;
                                        port++;
-                                       interp_set_entry(table, INTERP_SLOT_PORT, port);
+                                       free(tcp_port);
+                                       tcp_port = xstrdup(port);
                                }
-                               interp_set_entry(table, INTERP_SLOT_HOST, host);
+                               free(hostname);
+                               hostname = xstrdup(host);
                        }
 
                        /* On to the next one */
                        extra_args = val + vallen;
                }
        }
-}
-
-static void fill_in_extra_table_entries(struct interp *itable)
-{
-       char *hp;
 
        /*
         * Replace literal host with lowercase-ized hostname.
         */
-       hp = interp_table[INTERP_SLOT_HOST].value;
+       hp = hostname;
        if (!hp)
                return;
        for ( ; *hp; hp++)
@@ -490,17 +461,17 @@ static void fill_in_extra_table_entries(struct interp *itable)
                memset(&hints, 0, sizeof(hints));
                hints.ai_flags = AI_CANONNAME;
 
-               gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
+               gai = getaddrinfo(hostname, 0, &hints, &ai0);
                if (!gai) {
                        for (ai = ai0; ai; ai = ai->ai_next) {
                                struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 
                                inet_ntop(AF_INET, &sin_addr->sin_addr,
                                          addrbuf, sizeof(addrbuf));
-                               interp_set_entry(interp_table,
-                                                INTERP_SLOT_CANON_HOST, ai->ai_canonname);
-                               interp_set_entry(interp_table,
-                                                INTERP_SLOT_IP, addrbuf);
+                               free(canon_hostname);
+                               canon_hostname = xstrdup(ai->ai_canonname);
+                               free(ip_address);
+                               ip_address = xstrdup(addrbuf);
                                break;
                        }
                        freeaddrinfo(ai0);
@@ -513,7 +484,7 @@ static void fill_in_extra_table_entries(struct interp *itable)
                char **ap;
                static char addrbuf[HOST_NAME_MAX + 1];
 
-               hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
+               hent = gethostbyname(hostname);
 
                ap = hent->h_addr_list;
                memset(&sa, 0, sizeof sa);
@@ -524,8 +495,10 @@ static void fill_in_extra_table_entries(struct interp *itable)
                inet_ntop(hent->h_addrtype, &sa.sin_addr,
                          addrbuf, sizeof(addrbuf));
 
-               interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
-               interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
+               free(canon_hostname);
+               canon_hostname = xstrdup(hent->h_name);
+               free(ip_address);
+               ip_address = xstrdup(addrbuf);
        }
 #endif
 }
@@ -557,6 +530,10 @@ static int execute(struct sockaddr *addr)
 #endif
                }
                loginfo("Connection from %s:%d", addrbuf, port);
+               setenv("REMOTE_ADDR", addrbuf, 1);
+       }
+       else {
+               unsetenv("REMOTE_ADDR");
        }
 
        alarm(init_timeout ? init_timeout : timeout);
@@ -573,16 +550,14 @@ static int execute(struct sockaddr *addr)
                pktlen--;
        }
 
-       /*
-        * Initialize the path interpolation table for this connection.
-        */
-       interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
-       interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
+       free(hostname);
+       free(canon_hostname);
+       free(ip_address);
+       free(tcp_port);
+       hostname = canon_hostname = ip_address = tcp_port = NULL;
 
-       if (len != pktlen) {
-           parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
-           fill_in_extra_table_entries(interp_table);
-       }
+       if (len != pktlen)
+               parse_extra_args(line + len + 1, pktlen - len - 1);
 
        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
                struct daemon_service *s = &(daemon_service[i]);
@@ -594,9 +569,7 @@ static int execute(struct sockaddr *addr)
                         * Note: The directory here is probably context sensitive,
                         * and might depend on the actual service being performed.
                         */
-                       interp_set_entry(interp_table,
-                                        INTERP_SLOT_DIR, line + namelen + 5);
-                       return run_service(interp_table, s);
+                       return run_service(line + namelen + 5, s);
                }
        }
 
@@ -604,169 +577,107 @@ static int execute(struct sockaddr *addr)
        return -1;
 }
 
+static int max_connections = 32;
 
-/*
- * We count spawned/reaped separately, just to avoid any
- * races when updating them from signals. The SIGCHLD handler
- * will only update children_reaped, and the fork logic will
- * only update children_spawned.
- *
- * MAX_CHILDREN should be a power-of-two to make the modulus
- * operation cheap. It should also be at least twice
- * the maximum number of connections we will ever allow.
- */
-#define MAX_CHILDREN 128
-
-static int max_connections = 25;
-
-/* These are updated by the signal handler */
-static volatile unsigned int children_reaped;
-static pid_t dead_child[MAX_CHILDREN];
-
-/* These are updated by the main loop */
-static unsigned int children_spawned;
-static unsigned int children_deleted;
+static unsigned int live_children;
 
 static struct child {
+       struct child *next;
        pid_t pid;
-       int addrlen;
        struct sockaddr_storage address;
-} live_child[MAX_CHILDREN];
+} *firstborn;
 
-static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
+static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 {
-       live_child[idx].pid = pid;
-       live_child[idx].addrlen = addrlen;
-       memcpy(&live_child[idx].address, addr, addrlen);
+       struct child *newborn, **cradle;
+
+       /*
+        * This must be xcalloc() -- we'll compare the whole sockaddr_storage
+        * but individual address may be shorter.
+        */
+       newborn = xcalloc(1, sizeof(*newborn));
+       live_children++;
+       newborn->pid = pid;
+       memcpy(&newborn->address, addr, addrlen);
+       for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
+               if (!memcmp(&(*cradle)->address, &newborn->address,
+                           sizeof(newborn->address)))
+                       break;
+       newborn->next = *cradle;
+       *cradle = newborn;
 }
 
-/*
- * Walk from "deleted" to "spawned", and remove child "pid".
- *
- * We move everything up by one, since the new "deleted" will
- * be one higher.
- */
-static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
+static void remove_child(pid_t pid)
 {
-       struct child n;
+       struct child **cradle, *blanket;
 
-       deleted %= MAX_CHILDREN;
-       spawned %= MAX_CHILDREN;
-       if (live_child[deleted].pid == pid) {
-               live_child[deleted].pid = -1;
-               return;
-       }
-       n = live_child[deleted];
-       for (;;) {
-               struct child m;
-               deleted = (deleted + 1) % MAX_CHILDREN;
-               if (deleted == spawned)
-                       die("could not find dead child %d\n", pid);
-               m = live_child[deleted];
-               live_child[deleted] = n;
-               if (m.pid == pid)
-                       return;
-               n = m;
-       }
+       for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
+               if (blanket->pid == pid) {
+                       *cradle = blanket->next;
+                       live_children--;
+                       free(blanket);
+                       break;
+               }
 }
 
 /*
  * This gets called if the number of connections grows
  * past "max_connections".
  *
- * We _should_ start off by searching for connections
- * from the same IP, and if there is some address wth
- * multiple connections, we should kill that first.
- *
- * As it is, we just "randomly" kill 25% of the connections,
- * and our pseudo-random generator sucks too. I have no
- * shame.
- *
- * Really, this is just a place-holder for a _real_ algorithm.
+ * We kill the newest connection from a duplicate IP.
  */
-static void kill_some_children(int signo, unsigned start, unsigned stop)
+static void kill_some_child(void)
 {
-       start %= MAX_CHILDREN;
-       stop %= MAX_CHILDREN;
-       while (start != stop) {
-               if (!(start & 3))
-                       kill(live_child[start].pid, signo);
-               start = (start + 1) % MAX_CHILDREN;
-       }
-}
-
-static void check_dead_children(void)
-{
-       unsigned spawned, reaped, deleted;
-
-       spawned = children_spawned;
-       reaped = children_reaped;
-       deleted = children_deleted;
+       const struct child *blanket, *next;
 
-       while (deleted < reaped) {
-               pid_t pid = dead_child[deleted % MAX_CHILDREN];
-               const char *dead = pid < 0 ? " (with error)" : "";
-
-               if (pid < 0)
-                       pid = -pid;
+       if (!(blanket = firstborn))
+               return;
 
-               /* XXX: Custom logging, since we don't wanna getpid() */
-               if (verbose) {
-                       if (log_syslog)
-                               syslog(LOG_INFO, "[%d] Disconnected%s",
-                                               pid, dead);
-                       else
-                               fprintf(stderr, "[%d] Disconnected%s\n",
-                                               pid, dead);
+       for (; (next = blanket->next); blanket = next)
+               if (!memcmp(&blanket->address, &next->address,
+                           sizeof(next->address))) {
+                       kill(blanket->pid, SIGTERM);
+                       break;
                }
-               remove_child(pid, deleted, spawned);
-               deleted++;
-       }
-       children_deleted = deleted;
 }
 
-static void check_max_connections(void)
+static void check_dead_children(void)
 {
-       for (;;) {
-               int active;
-               unsigned spawned, deleted;
-
-               check_dead_children();
-
-               spawned = children_spawned;
-               deleted = children_deleted;
-
-               active = spawned - deleted;
-               if (active <= max_connections)
-                       break;
-
-               /* Kill some unstarted connections with SIGTERM */
-               kill_some_children(SIGTERM, deleted, spawned);
-               if (active <= max_connections << 1)
-                       break;
+       int status;
+       pid_t pid;
 
-               /* If the SIGTERM thing isn't helping use SIGKILL */
-               kill_some_children(SIGKILL, deleted, spawned);
-               sleep(1);
+       while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
+               const char *dead = "";
+               remove_child(pid);
+               if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
+                       dead = " (with error)";
+               loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
        }
 }
 
 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 {
-       pid_t pid = fork();
+       pid_t pid;
 
-       if (pid) {
-               unsigned idx;
+       if (max_connections && live_children >= max_connections) {
+               kill_some_child();
+               sleep(1);  /* give it some time to die */
+               check_dead_children();
+               if (live_children >= max_connections) {
+                       close(incoming);
+                       logerror("Too many children, dropping connection");
+                       return;
+               }
+       }
 
+       if ((pid = fork())) {
                close(incoming);
-               if (pid < 0)
+               if (pid < 0) {
+                       logerror("Couldn't fork %s", strerror(errno));
                        return;
+               }
 
-               idx = children_spawned % MAX_CHILDREN;
-               children_spawned++;
-               add_child(idx, pid, addr, addrlen);
-
-               check_max_connections();
+               add_child(pid, addr, addrlen);
                return;
        }
 
@@ -779,21 +690,11 @@ static void handle(int incoming, struct sockaddr *addr, int addrlen)
 
 static void child_handler(int signo)
 {
-       for (;;) {
-               int status;
-               pid_t pid = waitpid(-1, &status, WNOHANG);
-
-               if (pid > 0) {
-                       unsigned reaped = children_reaped;
-                       if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
-                               pid = -pid;
-                       dead_child[reaped % MAX_CHILDREN] = pid;
-                       children_reaped = reaped + 1;
-                       write(child_handler_pipe[1], &status, 1);
-                       continue;
-               }
-               break;
-       }
+       /*
+        * Otherwise empty handler because systemcalls will get interrupted
+        * upon signal receipt
+        * SysV needs the handler to be rearmed
+        */
        signal(SIGCHLD, child_handler);
 }
 
@@ -836,7 +737,7 @@ static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
                if (sockfd < 0)
                        continue;
                if (sockfd >= FD_SETSIZE) {
-                       error("too large socket descriptor.");
+                       logerror("Socket descriptor too large");
                        close(sockfd);
                        continue;
                }
@@ -936,35 +837,28 @@ static int service_loop(int socknum, int *socklist)
        struct pollfd *pfd;
        int i;
 
-       if (pipe(child_handler_pipe) < 0)
-               die ("Could not set up pipe for child handler");
-
-       pfd = xcalloc(socknum + 1, sizeof(struct pollfd));
+       pfd = xcalloc(socknum, sizeof(struct pollfd));
 
        for (i = 0; i < socknum; i++) {
                pfd[i].fd = socklist[i];
                pfd[i].events = POLLIN;
        }
-       pfd[socknum].fd = child_handler_pipe[0];
-       pfd[socknum].events = POLLIN;
 
        signal(SIGCHLD, child_handler);
 
        for (;;) {
                int i;
 
-               if (poll(pfd, socknum + 1, -1) < 0) {
+               check_dead_children();
+
+               if (poll(pfd, socknum, -1) < 0) {
                        if (errno != EINTR) {
-                               error("poll failed, resuming: %s",
+                               logerror("Poll failed, resuming: %s",
                                      strerror(errno));
                                sleep(1);
                        }
                        continue;
                }
-               if (pfd[socknum].revents & POLLIN) {
-                       read(child_handler_pipe[0], &i, 1);
-                       check_dead_children();
-               }
 
                for (i = 0; i < socknum; i++) {
                        if (pfd[i].revents & POLLIN) {
@@ -1022,7 +916,7 @@ static void store_pid(const char *path)
        FILE *f = fopen(path, "w");
        if (!f)
                die("cannot open pid file %s: %s", path, strerror(errno));
-       if (fprintf(f, "%d\n", getpid()) < 0 || fclose(f) != 0)
+       if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
                die("failed to write pid file %s: %s", path, strerror(errno));
 }
 
@@ -1055,11 +949,6 @@ int main(int argc, char **argv)
        gid_t gid = 0;
        int i;
 
-       /* Without this we cannot rely on waitpid() to tell
-        * what happened to our children.
-        */
-       signal(SIGCHLD, SIG_DFL);
-
        for (i = 1; i < argc; i++) {
                char *arg = argv[i];
 
@@ -1105,6 +994,12 @@ int main(int argc, char **argv)
                        init_timeout = atoi(arg+15);
                        continue;
                }
+               if (!prefixcmp(arg, "--max-connections=")) {
+                       max_connections = atoi(arg+18);
+                       if (max_connections < 0)
+                               max_connections = 0;            /* unlimited */
+                       continue;
+               }
                if (!strcmp(arg, "--strict-paths")) {
                        strict_paths = 1;
                        continue;
@@ -1178,9 +1073,11 @@ int main(int argc, char **argv)
        }
 
        if (log_syslog) {
-               openlog("git-daemon", 0, LOG_DAEMON);
+               openlog("git-daemon", LOG_PID, LOG_DAEMON);
                set_die_routine(daemon_die);
-       }
+       } else
+               /* avoid splitting a message in the middle */
+               setvbuf(stderr, NULL, _IOLBF, 0);
 
        if (inetd_mode && (group_name || user_name))
                die("--user and --group are incompatible with --inetd");
@@ -1212,13 +1109,9 @@ int main(int argc, char **argv)
        if (strict_paths && (!ok_paths || !*ok_paths))
                die("option --strict-paths requires a whitelist");
 
-       if (base_path) {
-               struct stat st;
-
-               if (stat(base_path, &st) || !S_ISDIR(st.st_mode))
-                       die("base-path '%s' does not exist or "
-                           "is not a directory", base_path);
-       }
+       if (base_path && !is_directory(base_path))
+               die("base-path '%s' does not exist or is not a directory",
+                   base_path);
 
        if (inetd_mode) {
                struct sockaddr_storage ss;
@@ -1233,8 +1126,10 @@ int main(int argc, char **argv)
                return execute(peer);
        }
 
-       if (detach)
+       if (detach) {
                daemonize();
+               loginfo("Ready to rumble");
+       }
        else
                sanitize_stdfds();