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-rw-r--r--src/logger.c565
1 files changed, 565 insertions, 0 deletions
diff --git a/src/logger.c b/src/logger.c
new file mode 100644
index 0000000000..f81d2c5c8a
--- /dev/null
+++ b/src/logger.c
@@ -0,0 +1,565 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#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 <fcntl.h>
+
+#include "util.h"
+#include "log.h"
+#include "list.h"
+#include "sd-daemon.h"
+
+#define STREAM_BUFFER 2048
+#define STREAMS_MAX 256
+#define SERVER_FD_MAX 16
+#define TIMEOUT ((int) (10*MSEC_PER_SEC))
+
+typedef struct Stream Stream;
+
+typedef struct Server {
+ int syslog_fd;
+ int kmsg_fd;
+ int epoll_fd;
+
+ unsigned n_server_fd;
+
+ LIST_HEAD(Stream, streams);
+ unsigned n_streams;
+} Server;
+
+typedef enum StreamTarget {
+ STREAM_SYSLOG,
+ STREAM_KMSG
+} StreamTarget;
+
+typedef enum StreamState {
+ STREAM_TARGET,
+ STREAM_PRIORITY,
+ STREAM_PROCESS,
+ STREAM_PREFIX,
+ STREAM_RUNNING
+} StreamState;
+
+struct Stream {
+ Server *server;
+
+ StreamState state;
+
+ int fd;
+
+ LogTarget target;
+ int priority;
+ char *process;
+ pid_t pid;
+ uid_t uid;
+
+ bool prefix;
+
+ char buffer[STREAM_BUFFER];
+ size_t length;
+
+ LIST_FIELDS(Stream, stream);
+};
+
+static int stream_log(Stream *s, char *p, usec_t timestamp) {
+
+ char header_priority[16], header_time[64], header_pid[16];
+ struct iovec iovec[5];
+ int priority;
+
+ assert(s);
+ assert(p);
+
+ priority = s->priority;
+
+ if (s->prefix &&
+ p[0] == '<' &&
+ p[1] >= '0' && p[1] <= '7' &&
+ p[2] == '>') {
+
+ /* Detected priority prefix */
+ priority = LOG_MAKEPRI(LOG_FAC(priority), (p[1] - '0'));
+
+ p += 3;
+ }
+
+ if (*p == 0)
+ return 0;
+
+ /*
+ * The format glibc uses to talk to the syslog daemon is:
+ *
+ * <priority>time process[pid]: msg
+ *
+ * The format the kernel uses is:
+ *
+ * <priority>msg\n
+ *
+ * We extend the latter to include the process name and pid.
+ */
+
+ snprintf(header_priority, sizeof(header_priority), "<%i>",
+ s->target == STREAM_SYSLOG ? priority : LOG_PRI(priority));
+ char_array_0(header_priority);
+
+ if (s->target == STREAM_SYSLOG) {
+ time_t t;
+ struct tm *tm;
+
+ 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);
+
+ if (s->target == STREAM_SYSLOG) {
+ struct msghdr msghdr;
+
+ 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->syslog_fd, &msghdr, MSG_NOSIGNAL) < 0)
+ return -errno;
+
+ } else if (s->target == STREAM_KMSG) {
+ IOVEC_SET_STRING(iovec[1], s->process);
+ IOVEC_SET_STRING(iovec[2], header_pid);
+ IOVEC_SET_STRING(iovec[3], p);
+ IOVEC_SET_STRING(iovec[4], (char*) "\n");
+
+ if (writev(s->server->kmsg_fd, iovec, ELEMENTSOF(iovec)) < 0)
+ return -errno;
+ } else
+ assert_not_reached("Unknown log target");
+
+ 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_TARGET:
+ if (streq(p, "syslog"))
+ s->target = STREAM_SYSLOG;
+ else if (streq(p, "kmsg")) {
+
+ if (s->server->kmsg_fd >= 0 && s->uid == 0)
+ s->target = STREAM_KMSG;
+ else {
+ log_warning("/dev/kmsg logging not available.");
+ return -EPERM;
+ }
+ } else {
+ log_warning("Failed to parse log target line.");
+ return -EBADMSG;
+ }
+ s->state = STREAM_PRIORITY;
+ return 0;
+
+ case STREAM_PRIORITY:
+ if ((r = safe_atoi(p, &s->priority)) < 0) {
+ log_warning("Failed to parse log priority line: %s", strerror(errno));
+ return r;
+ }
+
+ if (s->priority < 0) {
+ log_warning("Log priority negative: %s", strerror(errno));
+ return -ERANGE;
+ }
+
+ s->state = STREAM_PROCESS;
+ return 0;
+
+ case STREAM_PROCESS:
+ if (!(s->process = strdup(p)))
+ return -ENOMEM;
+
+ s->state = STREAM_PREFIX;
+ return 0;
+
+ case STREAM_PREFIX:
+
+ if ((r = parse_boolean(p)) < 0)
+ return r;
+
+ s->prefix = r;
+ 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);
+
+ close_nointr_nofail(s->fd);
+ }
+
+ 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.");
+ close_nointr_nofail(fd);
+ return 0;
+ }
+
+ if (!(stream = new0(Stream, 1))) {
+ close_nointr_nofail(fd);
+ 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 = EPOLLIN;
+ if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ stream->pid = ucred.pid;
+ stream->uid = ucred.uid;
+
+ stream->server = s;
+ LIST_PREPEND(Stream, stream, s->streams, stream);
+ s->n_streams ++;
+
+ return 0;
+
+fail:
+ stream_free(stream);
+ return r;
+}
+
+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++)
+ close_nointr_nofail(SD_LISTEN_FDS_START+i);
+
+ if (s->syslog_fd >= 0)
+ close_nointr_nofail(s->syslog_fd);
+
+ if (s->epoll_fd >= 0)
+ close_nointr_nofail(s->epoll_fd);
+
+ if (s->kmsg_fd >= 0)
+ close_nointr_nofail(s->kmsg_fd);
+}
+
+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->syslog_fd = -1;
+ s->kmsg_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 = EPOLLIN;
+ ev.data.ptr = UINT_TO_PTR(SD_LISTEN_FDS_START+i);
+ if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, SD_LISTEN_FDS_START+i, &ev) < 0) {
+ r = -errno;
+ log_error("Failed to add server fd to epoll object: %s", strerror(errno));
+ goto fail;
+ }
+ }
+
+ if ((s->syslog_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->syslog_fd, &sa.sa, sizeof(sa)) < 0) {
+ r = -errno;
+ log_error("Failed to connect log socket to /dev/log: %s", strerror(errno));
+ goto fail;
+ }
+
+ /* /dev/kmsg logging is strictly optional */
+ if ((s->kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC)) < 0)
+ log_debug("Failed to open /dev/kmsg for logging, disabling kernel log buffer support: %s", strerror(errno));
+
+ 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 > SD_LISTEN_FDS_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) >= SD_LISTEN_FDS_START &&
+ PTR_TO_UINT(ev->data.ptr) < SD_LISTEN_FDS_START+s->n_server_fd) {
+
+ if (ev->events != EPOLLIN) {
+ 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 & EPOLLIN)) {
+ log_info("Got invalid event from epoll. (2)");
+ 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, n;
+
+ log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
+ log_parse_environment();
+
+ log_info("systemd-logger running as pid %llu", (unsigned long long) getpid());
+
+ if ((n = sd_listen_fds(true)) < 0) {
+ log_error("Failed to read listening file descriptors from environment: %s", strerror(-r));
+ return 1;
+ }
+
+ if (n <= 0 || n > SERVER_FD_MAX) {
+ log_error("No or too many file descriptors passed.");
+ return 2;
+ }
+
+ if (server_init(&server, (unsigned) n) < 0)
+ return 3;
+
+ for (;;) {
+ struct epoll_event event;
+ int k;
+
+ if ((k = 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 (k <= 0)
+ break;
+
+ if ((k = 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;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-10 08:38:11 +0000