diff options
| -rw-r--r-- | Documentation/git-daemon.txt | 9 | ||||
| -rw-r--r-- | daemon.c | 213 |
2 files changed, 82 insertions, 140 deletions
diff --git a/Documentation/git-daemon.txt b/Documentation/git-daemon.txt index 4ba4b75c1..b08a08cd9 100644 --- a/Documentation/git-daemon.txt +++ b/Documentation/git-daemon.txt @@ -9,8 +9,9 @@ SYNOPSIS -------- [verse] 'git daemon' [--verbose] [--syslog] [--export-all] - [--timeout=n] [--init-timeout=n] [--strict-paths] - [--base-path=path] [--user-path | --user-path=path] + [--timeout=n] [--init-timeout=n] [--max-connections=n] + [--strict-paths] [--base-path=path] [--base-path-relaxed] + [--user-path | --user-path=path] [--interpolated-path=pathtemplate] [--reuseaddr] [--detach] [--pid-file=file] [--enable=service] [--disable=service] @@ -99,6 +100,10 @@ OPTIONS it takes for the server to process the sub-request and time spent waiting for next client's request. +--max-connections:: + Maximum number of concurrent clients, defaults to 32. Set it to + zero for no limit. + --syslog:: Log to syslog instead of stderr. Note that this option does not imply --verbose, thus by default only error conditions will be logged. @@ -19,8 +19,8 @@ static int reuseaddr; 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" @@ -584,40 +584,35 @@ 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; + newborn = xcalloc(1, sizeof *newborn); + if (newborn) { + struct child **cradle; + + 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; + } + else + logerror("Out of memory spawning new child"); } /* @@ -626,142 +621,78 @@ static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen) * 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; - - 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; - continue; - } - break; - } - - spawned = children_spawned; - reaped = children_reaped; - deleted = children_deleted; - - while (deleted < reaped) { - pid_t pid = dead_child[deleted % MAX_CHILDREN]; - const char *dead = pid < 0 ? " (with error)" : ""; + const struct child *blanket; - if (pid < 0) - pid = -pid; + if ((blanket = firstborn)) { + const struct child *next; - /* 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); - } - remove_child(pid, deleted, spawned); - deleted++; + for (; (next = blanket->next); blanket = next) + if (!memcmp(&blanket->address, &next->address, + sizeof next->address)) { + kill(blanket->pid, SIGTERM); + break; + } } - 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("[%d] Disconnected%s", (int)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; } @@ -1077,6 +1008,12 @@ 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; |