systemd/src/journal/journald-stream.c

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2011 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <fcntl.h>
#include <unistd.h>
#include <stddef.h>

#ifdef HAVE_SELINUX
#include <selinux/selinux.h>
#endif

#include "sd-event.h"
#include "socket-util.h"
#include "selinux-util.h"
#include "journald-server.h"
#include "journald-stream.h"
#include "journald-syslog.h"
#include "journald-kmsg.h"
#include "journald-console.h"
#include "journald-wall.h"

#define STDOUT_STREAMS_MAX 4096

typedef enum StdoutStreamState {
        STDOUT_STREAM_IDENTIFIER,
        STDOUT_STREAM_UNIT_ID,
        STDOUT_STREAM_PRIORITY,
        STDOUT_STREAM_LEVEL_PREFIX,
        STDOUT_STREAM_FORWARD_TO_SYSLOG,
        STDOUT_STREAM_FORWARD_TO_KMSG,
        STDOUT_STREAM_FORWARD_TO_CONSOLE,
        STDOUT_STREAM_RUNNING
} StdoutStreamState;

struct StdoutStream {
        Server *server;
        StdoutStreamState state;

        int fd;

        struct ucred ucred;
#ifdef HAVE_SELINUX
        security_context_t security_context;
#endif

        char *identifier;
        char *unit_id;
        int priority;
        bool level_prefix:1;
        bool forward_to_syslog:1;
        bool forward_to_kmsg:1;
        bool forward_to_console:1;

        char buffer[LINE_MAX+1];
        size_t length;

        sd_event_source *event_source;

        LIST_FIELDS(StdoutStream, stdout_stream);
};

static int stdout_stream_log(StdoutStream *s, const char *p) {
        struct iovec iovec[N_IOVEC_META_FIELDS + 5];
        int priority;
        char syslog_priority[] = "PRIORITY=\0";
        char syslog_facility[sizeof("SYSLOG_FACILITY=") + DECIMAL_STR_MAX(priority)];
        _cleanup_free_ char *message = NULL, *syslog_identifier = NULL;
        unsigned n = 0;
        char *label = NULL;
        size_t label_len = 0;

        assert(s);
        assert(p);

        if (isempty(p))
                return 0;

        priority = s->priority;

        if (s->level_prefix)
                syslog_parse_priority(&p, &priority, false);

        if (s->forward_to_syslog || s->server->forward_to_syslog)
                server_forward_syslog(s->server, syslog_fixup_facility(priority), s->identifier, p, &s->ucred, NULL);

        if (s->forward_to_kmsg || s->server->forward_to_kmsg)
                server_forward_kmsg(s->server, priority, s->identifier, p, &s->ucred);

        if (s->forward_to_console || s->server->forward_to_console)
                server_forward_console(s->server, priority, s->identifier, p, &s->ucred);

        if (s->server->forward_to_wall)
                server_forward_wall(s->server, priority, s->identifier, p, &s->ucred);

        IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=stdout");

        syslog_priority[strlen("PRIORITY=")] = '0' + LOG_PRI(priority);
        IOVEC_SET_STRING(iovec[n++], syslog_priority);

        if (priority & LOG_FACMASK) {
                snprintf(syslog_facility, sizeof(syslog_facility), "SYSLOG_FACILITY=%i", LOG_FAC(priority));
                IOVEC_SET_STRING(iovec[n++], syslog_facility);
        }

        if (s->identifier) {
                syslog_identifier = strappend("SYSLOG_IDENTIFIER=", s->identifier);
                if (syslog_identifier)
                        IOVEC_SET_STRING(iovec[n++], syslog_identifier);
        }

        message = strappend("MESSAGE=", p);
        if (message)
                IOVEC_SET_STRING(iovec[n++], message);

#ifdef HAVE_SELINUX
        if (s->security_context) {
                label = (char*) s->security_context;
                label_len = strlen((char*) s->security_context);
        }
#endif

        server_dispatch_message(s->server, iovec, n, ELEMENTSOF(iovec), &s->ucred, NULL, label, label_len, s->unit_id, priority, 0);
        return 0;
}

static int stdout_stream_line(StdoutStream *s, char *p) {
        int r;

        assert(s);
        assert(p);

        p = strstrip(p);

        switch (s->state) {

        case STDOUT_STREAM_IDENTIFIER:
                if (isempty(p))
                        s->identifier = NULL;
                else  {
                        s->identifier = strdup(p);
                        if (!s->identifier)
                                return log_oom();
                }

                s->state = STDOUT_STREAM_UNIT_ID;
                return 0;

        case STDOUT_STREAM_UNIT_ID:
                if (s->ucred.uid == 0) {
                        if (isempty(p))
                                s->unit_id = NULL;
                        else  {
                                s->unit_id = strdup(p);
                                if (!s->unit_id)
                                        return log_oom();
                        }
                }

                s->state = STDOUT_STREAM_PRIORITY;
                return 0;

        case STDOUT_STREAM_PRIORITY:
                r = safe_atoi(p, &s->priority);
                if (r < 0 || s->priority < 0 || s->priority > 999) {
                        log_warning("Failed to parse log priority line.");
                        return -EINVAL;
                }

                s->state = STDOUT_STREAM_LEVEL_PREFIX;
                return 0;

        case STDOUT_STREAM_LEVEL_PREFIX:
                r = parse_boolean(p);
                if (r < 0) {
                        log_warning("Failed to parse level prefix line.");
                        return -EINVAL;
                }

                s->level_prefix = !!r;
                s->state = STDOUT_STREAM_FORWARD_TO_SYSLOG;
                return 0;

        case STDOUT_STREAM_FORWARD_TO_SYSLOG:
                r = parse_boolean(p);
                if (r < 0) {
                        log_warning("Failed to parse forward to syslog line.");
                        return -EINVAL;
                }

                s->forward_to_syslog = !!r;
                s->state = STDOUT_STREAM_FORWARD_TO_KMSG;
                return 0;

        case STDOUT_STREAM_FORWARD_TO_KMSG:
                r = parse_boolean(p);
                if (r < 0) {
                        log_warning("Failed to parse copy to kmsg line.");
                        return -EINVAL;
                }

                s->forward_to_kmsg = !!r;
                s->state = STDOUT_STREAM_FORWARD_TO_CONSOLE;
                return 0;

        case STDOUT_STREAM_FORWARD_TO_CONSOLE:
                r = parse_boolean(p);
                if (r < 0) {
                        log_warning("Failed to parse copy to console line.");
                        return -EINVAL;
                }

                s->forward_to_console = !!r;
                s->state = STDOUT_STREAM_RUNNING;
                return 0;

        case STDOUT_STREAM_RUNNING:
                return stdout_stream_log(s, p);
        }

        assert_not_reached("Unknown stream state");
}

static int stdout_stream_scan(StdoutStream *s, bool force_flush) {
        char *p;
        size_t remaining;
        int r;

        assert(s);

        p = s->buffer;
        remaining = s->length;
        for (;;) {
                char *end;
                size_t skip;

                end = memchr(p, '\n', remaining);
                if (end)
                        skip = end - p + 1;
                else if (remaining >= sizeof(s->buffer) - 1) {
                        end = p + sizeof(s->buffer) - 1;
                        skip = remaining;
                } else
                        break;

                *end = 0;

                r = stdout_stream_line(s, p);
                if (r < 0)
                        return r;

                remaining -= skip;
                p += skip;
        }

        if (force_flush && remaining > 0) {
                p[remaining] = 0;
                r = stdout_stream_line(s, p);
                if (r < 0)
                        return r;

                p += remaining;
                remaining = 0;
        }

        if (p > s->buffer) {
                memmove(s->buffer, p, remaining);
                s->length = remaining;
        }

        return 0;
}

static int stdout_stream_process(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
        StdoutStream *s = userdata;
        ssize_t l;
        int r;

        assert(s);

        if ((revents|EPOLLIN|EPOLLHUP) != (EPOLLIN|EPOLLHUP)) {
                log_error("Got invalid event from epoll for stdout stream: %"PRIx32, revents);
                goto terminate;
        }

        l = read(s->fd, s->buffer+s->length, sizeof(s->buffer)-1-s->length);
        if (l < 0) {

                if (errno == EAGAIN)
                        return 0;

                log_warning("Failed to read from stream: %m");
                goto terminate;
        }

        if (l == 0) {
                stdout_stream_scan(s, true);
                goto terminate;
        }

        s->length += l;
        r = stdout_stream_scan(s, false);
        if (r < 0)
                goto terminate;

        return 1;

terminate:
        stdout_stream_free(s);
        return 0;
}

void stdout_stream_free(StdoutStream *s) {
        assert(s);

        if (s->server) {
                assert(s->server->n_stdout_streams > 0);
                s->server->n_stdout_streams --;
                LIST_REMOVE(stdout_stream, s->server->stdout_streams, s);
        }

        if (s->event_source) {
                sd_event_source_set_enabled(s->event_source, SD_EVENT_OFF);
                s->event_source = sd_event_source_unref(s->event_source);
        }

        safe_close(s->fd);

#ifdef HAVE_SELINUX
        if (s->security_context)
                freecon(s->security_context);
#endif

        free(s->identifier);
        free(s->unit_id);
        free(s);
}

static int stdout_stream_new(sd_event_source *es, int listen_fd, uint32_t revents, void *userdata) {
        Server *s = userdata;
        StdoutStream *stream;
        int fd, r;

        assert(s);

        if (revents != EPOLLIN) {
                log_error("Got invalid event from epoll for stdout server fd: %"PRIx32, revents);
                return -EIO;
        }

        fd = accept4(s->stdout_fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
        if (fd < 0) {
                if (errno == EAGAIN)
                        return 0;

                log_error("Failed to accept stdout connection: %m");
                return -errno;
        }

        if (s->n_stdout_streams >= STDOUT_STREAMS_MAX) {
                log_warning("Too many stdout streams, refusing connection.");
                safe_close(fd);
                return 0;
        }

        stream = new0(StdoutStream, 1);
        if (!stream) {
                safe_close(fd);
                return log_oom();
        }

        stream->fd = fd;

        r = getpeercred(fd, &stream->ucred);
        if (r < 0) {
                log_error("Failed to determine peer credentials: %m");
                goto fail;
        }

#ifdef HAVE_SELINUX
        if (use_selinux()) {
                if (getpeercon(fd, &stream->security_context) < 0 && errno != ENOPROTOOPT)
                        log_error("Failed to determine peer security context: %m");
        }
#endif

        if (shutdown(fd, SHUT_WR) < 0) {
                log_error("Failed to shutdown writing side of socket: %m");
                goto fail;
        }

        r = sd_event_add_io(s->event, &stream->event_source, fd, EPOLLIN, stdout_stream_process, stream);
        if (r < 0) {
                log_error("Failed to add stream to event loop: %s", strerror(-r));
                goto fail;
        }

        r = sd_event_source_set_priority(stream->event_source, SD_EVENT_PRIORITY_NORMAL+5);
        if (r < 0) {
                log_error("Failed to adjust stdout event source priority: %s", strerror(-r));
                goto fail;
        }

        stream->server = s;
        LIST_PREPEND(stdout_stream, s->stdout_streams, stream);
        s->n_stdout_streams ++;

        return 0;

fail:
        stdout_stream_free(stream);
        return 0;
}

int server_open_stdout_socket(Server *s) {
        int r;

        assert(s);

        if (s->stdout_fd < 0) {
                union sockaddr_union sa = {
                        .un.sun_family = AF_UNIX,
                        .un.sun_path = "/run/systemd/journal/stdout",
                };

                s->stdout_fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
                if (s->stdout_fd < 0) {
                        log_error("socket() failed: %m");
                        return -errno;
                }

                unlink(sa.un.sun_path);

                r = bind(s->stdout_fd, &sa.sa, offsetof(union sockaddr_union, un.sun_path) + strlen(sa.un.sun_path));
                if (r < 0) {
                        log_error("bind() failed: %m");
                        return -errno;
                }

                chmod(sa.un.sun_path, 0666);

                if (listen(s->stdout_fd, SOMAXCONN) < 0) {
                        log_error("listen() failed: %m");
                        return -errno;
                }
        } else
                fd_nonblock(s->stdout_fd, 1);

        r = sd_event_add_io(s->event, &s->stdout_event_source, s->stdout_fd, EPOLLIN, stdout_stream_new, s);
        if (r < 0) {
                log_error("Failed to add stdout server fd to event source: %s", strerror(-r));
                return r;
        }

        r = sd_event_source_set_priority(s->stdout_event_source, SD_EVENT_PRIORITY_NORMAL+10);
        if (r < 0) {
                log_error("Failed to adjust priority of stdout server event source: %s", strerror(-r));
                return r;
        }

        return 0;
}