diff options
Diffstat (limited to 'logger.c')
| -rw-r--r-- | logger.c | 496 |
1 files changed, 496 insertions, 0 deletions
diff --git a/logger.c b/logger.c new file mode 100644 index 0000000000..c7c4cb83d2 --- /dev/null +++ b/logger.c @@ -0,0 +1,496 @@ +/*-*- Mode: C; c-basic-offset: 8 -*-*/ + +#include <sys/socket.h> +#include <sys/types.h> +#include <assert.h> +#include <time.h> +#include <string.h> +#include <stdio.h> +#include <errno.h> +#include <unistd.h> +#include <sys/poll.h> +#include <sys/epoll.h> +#include <sys/un.h> + +#include "util.h" +#include "log.h" +#include "list.h" + +#define STREAM_BUFFER 2048 +#define STREAMS_MAX 256 +#define SERVER_FD_START 3 +#define SERVER_FD_MAX 16 +#define TIMEOUT ((int) (10*MSEC_PER_SEC)) + +typedef struct Stream Stream; + +typedef struct Server { + int log_fd; + int epoll_fd; + + unsigned n_server_fd; + + LIST_HEAD(Stream, streams); + unsigned n_streams; +} Server; + +typedef enum StreamState { + STREAM_PRIORITY, + STREAM_PROCESS, + STREAM_RUNNING +} StreamState; + +struct Stream { + Server *server; + + StreamState state; + + int fd; + int priority; + char *process; + + char buffer[STREAM_BUFFER]; + size_t length; + + pid_t pid; + + LIST_FIELDS(Stream, stream); +}; + +#define IOVEC_SET_STRING(iovec, s) \ + do { \ + (iovec).iov_base = s; \ + (iovec).iov_len = strlen(s); \ + } while(false); + +static int stream_log(Stream *s, char *p, usec_t timestamp) { + + char header_priority[16], header_time[64], header_pid[16]; + time_t t; + struct tm *tm; + struct msghdr msghdr; + struct iovec iovec[5]; + + assert(s); + assert(p); + + if (*p == 0) + return 0; + + /* + * The format glibc uses is: + * + * <priority>time process[pid]: msg + */ + + snprintf(header_priority, sizeof(header_priority), "<%i>", s->priority); + char_array_0(header_priority); + + t = (time_t) (timestamp / USEC_PER_SEC); + if (!(tm = localtime(&t))) + return -EINVAL; + + if (strftime(header_time, sizeof(header_time), "%h %e %T ", tm) <= 0) + return -EINVAL; + + snprintf(header_pid, sizeof(header_pid), "[%llu]: ", (unsigned long long) s->pid); + char_array_0(header_pid); + + zero(iovec); + IOVEC_SET_STRING(iovec[0], header_priority); + IOVEC_SET_STRING(iovec[1], header_time); + IOVEC_SET_STRING(iovec[2], s->process); + IOVEC_SET_STRING(iovec[3], header_pid); + IOVEC_SET_STRING(iovec[4], p); + + zero(msghdr); + msghdr.msg_iov = iovec; + msghdr.msg_iovlen = ELEMENTSOF(iovec); + + if (sendmsg(s->server->log_fd, &msghdr, MSG_NOSIGNAL) < 0) + return -errno; + + return 0; +} + +static int stream_line(Stream *s, char *p, usec_t timestamp) { + int r; + + assert(s); + assert(p); + + p = strstrip(p); + + switch (s->state) { + + case STREAM_PRIORITY: + if ((r = safe_atoi(p, &s->priority)) < 0) + return r; + + if (s->priority < 0) + return -ERANGE; + + s->state = STREAM_PROCESS; + return 0; + + case STREAM_PROCESS: + if (!(s->process = strdup(p))) + return -ENOMEM; + + s->state = STREAM_RUNNING; + return 0; + + case STREAM_RUNNING: + return stream_log(s, p, timestamp); + } + + assert_not_reached("Unknown stream state"); +} + +static int stream_scan(Stream *s, usec_t timestamp) { + char *p; + size_t remaining; + int r = 0; + + assert(s); + + p = s->buffer; + remaining = s->length; + for (;;) { + char *newline; + + if (!(newline = memchr(p, '\n', remaining))) + break; + + *newline = 0; + + if ((r = stream_line(s, p, timestamp)) >= 0) { + remaining -= newline-p+1; + p = newline+1; + } + } + + if (p > s->buffer) { + memmove(s->buffer, p, remaining); + s->length = remaining; + } + + return r; +} + +static int stream_process(Stream *s, usec_t timestamp) { + ssize_t l; + int r; + assert(s); + + if ((l = read(s->fd, s->buffer+s->length, STREAM_BUFFER-s->length)) < 0) { + + if (errno == EAGAIN) + return 0; + + log_warning("Failed to read from stream: %s", strerror(errno)); + return -1; + } + + + if (l == 0) + return 0; + + s->length += l; + r = stream_scan(s, timestamp); + + if (r < 0) + return r; + + return 1; +} + +static void stream_free(Stream *s) { + assert(s); + + if (s->server) { + assert(s->server->n_streams > 0); + s->server->n_streams--; + LIST_REMOVE(Stream, stream, s->server->streams, s); + + } + + if (s->fd >= 0) { + if (s->server) + epoll_ctl(s->server->epoll_fd, EPOLL_CTL_DEL, s->fd, NULL); + + assert_se(close_nointr(s->fd) == 0); + } + + free(s->process); + free(s); +} + +static int stream_new(Server *s, int server_fd) { + Stream *stream; + int fd; + struct ucred ucred; + socklen_t len = sizeof(ucred); + struct epoll_event ev; + int r; + + assert(s); + + if ((fd = accept4(server_fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC)) < 0) + return -errno; + + if (s->n_streams >= STREAMS_MAX) { + log_warning("Too many connections, refusing connection."); + assert_se(close_nointr(fd) == 0); + return 0; + } + + if (!(stream = new0(Stream, 1))) { + assert_se(close_nointr(fd) == 0); + return -ENOMEM; + } + + stream->fd = fd; + + if (getsockopt(stream->fd, SOL_SOCKET, SO_PEERCRED, &ucred, &len) < 0) { + r = -errno; + goto fail; + } + + if (shutdown(fd, SHUT_WR) < 0) { + r = -errno; + goto fail; + } + + zero(ev); + ev.data.ptr = stream; + ev.events = POLLIN; + if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) { + r = -errno; + goto fail; + } + + stream->pid = ucred.pid; + + stream->server = s; + LIST_PREPEND(Stream, stream, s->streams, stream); + s->n_streams ++; + + return 0; + +fail: + stream_free(stream); + return r; +} + +static int verify_environment(unsigned *n_sockets) { + unsigned long long pid; + const char *e; + int r; + unsigned ns; + + assert_se(n_sockets); + + if (!(e = getenv("LISTEN_PID"))) { + log_error("Missing $LISTEN_PID environment variable."); + return -ENOENT; + } + + if ((r = safe_atollu(e, &pid)) < 0) { + log_error("Failed to parse $LISTEN_PID: %s", strerror(-r)); + return r; + } + + if (pid != (unsigned long long) getpid()) { + log_error("Socket nor for me."); + return -ENOENT; + } + + if (!(e = getenv("LISTEN_FDS"))) { + log_error("Missing $LISTEN_FDS environment variable."); + return -ENOENT; + } + + if ((r = safe_atou(e, &ns)) < 0) { + log_error("Failed to parse $LISTEN_FDS: %s", strerror(-r)); + return -E2BIG; + } + + if (ns <= 0 || ns > SERVER_FD_MAX) { + log_error("Wrong number of file descriptors passed: %s", e); + return -E2BIG; + } + + *n_sockets = ns; + + return 0; +} + +static void server_done(Server *s) { + unsigned i; + assert(s); + + while (s->streams) + stream_free(s->streams); + + for (i = 0; i < s->n_server_fd; i++) + assert_se(close_nointr(SERVER_FD_START+i) == 0); + + if (s->log_fd >= 0) + assert_se(close_nointr(s->log_fd) == 0); + + if (s->epoll_fd >= 0) + assert_se(close_nointr(s->epoll_fd) == 0); +} + +static int server_init(Server *s, unsigned n_sockets) { + int r; + unsigned i; + union { + struct sockaddr sa; + struct sockaddr_un un; + } sa; + + assert(s); + assert(n_sockets > 0); + + zero(*s); + + s->n_server_fd = n_sockets; + s->log_fd = -1; + + if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) { + r = -errno; + log_error("Failed to create epoll object: %s", strerror(errno)); + goto fail; + } + + for (i = 0; i < n_sockets; i++) { + struct epoll_event ev; + + zero(ev); + ev.events = POLLIN; + ev.data.ptr = UINT_TO_PTR(SERVER_FD_START+i); + if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, SERVER_FD_START+i, &ev) < 0) { + r = -errno; + log_error("Failed to add server fd to epoll object: %s", strerror(errno)); + goto fail; + } + } + + if ((s->log_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) { + r = -errno; + log_error("Failed to create log fd: %s", strerror(errno)); + goto fail; + } + + zero(sa); + sa.un.sun_family = AF_UNIX; + strncpy(sa.un.sun_path, "/dev/log", sizeof(sa.un.sun_path)); + + if (connect(s->log_fd, &sa.sa, sizeof(sa)) < 0) { + r = -errno; + log_error("Failed to connect log socket to /dev/log: %s", strerror(errno)); + goto fail; + } + + return 0; + +fail: + server_done(s); + return r; +} + +static int process_event(Server *s, struct epoll_event *ev) { + int r; + + assert(s); + + /* Yes, this is a bit ugly, we assume that that valid pointers + * are > SERVER_FD_START+SERVER_FD_MAX. Which is certainly + * true on Linux (and probably most other OSes, too, since the + * first 4k usually are part of a seperate null pointer + * dereference page. */ + + if (PTR_TO_UINT(ev->data.ptr) >= SERVER_FD_START && + PTR_TO_UINT(ev->data.ptr) < SERVER_FD_START+s->n_server_fd) { + + if (ev->events != POLLIN) { + log_info("Got invalid event from epoll. (1)"); + return -EIO; + } + + if ((r = stream_new(s, PTR_TO_UINT(ev->data.ptr))) < 0) { + log_info("Failed to accept new connection: %s", strerror(-r)); + return r; + } + + } else { + usec_t timestamp; + Stream *stream = ev->data.ptr; + + timestamp = now(CLOCK_REALTIME); + + if (!(ev->events & POLLIN)) { + log_info("Got invalid event from epoll. (3)"); + stream_free(stream); + return 0; + } + + if ((r = stream_process(stream, timestamp)) <= 0) { + + if (r < 0) + log_info("Got error on stream: %s", strerror(-r)); + + stream_free(stream); + return 0; + } + } + + return 0; +} + +int main(int argc, char *argv[]) { + Server server; + int r = 3; + unsigned n; + + log_info("systemd-logger running as pid %llu", (unsigned long long) getpid()); + + if (verify_environment(&n) < 0) + return 1; + + if (server_init(&server, n) < 0) + return 2; + + + for (;;) { + struct epoll_event event; + int n; + + if ((n = epoll_wait(server.epoll_fd, + &event, 1, + server.n_streams <= 0 ? TIMEOUT : -1)) < 0) { + + if (errno == EINTR) + continue; + + log_error("epoll_wait() failed: %s", strerror(errno)); + goto fail; + } + + if (n <= 0) + break; + + if ((r = process_event(&server, &event)) < 0) + goto fail; + } + r = 0; + +fail: + server_done(&server); + + log_info("systemd-logger stopped as pid %llu", (unsigned long long) getpid()); + + return r; +} |