From ef63833d532dd86bdba63211e6a1363cbb3ef61d Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 22 Aug 2012 03:09:44 +0200 Subject: journald: split /dev/kmsg related stuff into its own .c file --- src/journal/journald-kmsg.c | 437 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 437 insertions(+) create mode 100644 src/journal/journald-kmsg.c (limited to 'src/journal/journald-kmsg.c') diff --git a/src/journal/journald-kmsg.c b/src/journal/journald-kmsg.c new file mode 100644 index 0000000000..cc0080da19 --- /dev/null +++ b/src/journal/journald-kmsg.c @@ -0,0 +1,437 @@ +/*-*- 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 . +***/ + +#include +#include +#include +#include + +#include +#include + +#include "journald.h" +#include "journald-kmsg.h" + +void server_forward_kmsg( + Server *s, + int priority, + const char *identifier, + const char *message, + struct ucred *ucred) { + + struct iovec iovec[5]; + char header_priority[6], header_pid[16]; + int n = 0; + char *ident_buf = NULL; + + assert(s); + assert(priority >= 0); + assert(priority <= 999); + assert(message); + + if (_unlikely_(LOG_PRI(priority) > s->max_level_kmsg)) + return; + + if (_unlikely_(s->dev_kmsg_fd < 0)) + return; + + /* Never allow messages with kernel facility to be written to + * kmsg, regardless where the data comes from. */ + priority = syslog_fixup_facility(priority); + + /* First: priority field */ + snprintf(header_priority, sizeof(header_priority), "<%i>", priority); + char_array_0(header_priority); + IOVEC_SET_STRING(iovec[n++], header_priority); + + /* Second: identifier and PID */ + if (ucred) { + if (!identifier) { + get_process_comm(ucred->pid, &ident_buf); + identifier = ident_buf; + } + + snprintf(header_pid, sizeof(header_pid), "[%lu]: ", (unsigned long) ucred->pid); + char_array_0(header_pid); + + if (identifier) + IOVEC_SET_STRING(iovec[n++], identifier); + + IOVEC_SET_STRING(iovec[n++], header_pid); + } else if (identifier) { + IOVEC_SET_STRING(iovec[n++], identifier); + IOVEC_SET_STRING(iovec[n++], ": "); + } + + /* Fourth: message */ + IOVEC_SET_STRING(iovec[n++], message); + IOVEC_SET_STRING(iovec[n++], "\n"); + + if (writev(s->dev_kmsg_fd, iovec, n) < 0) + log_debug("Failed to write to /dev/kmsg for logging: %s", strerror(errno)); + + free(ident_buf); +} + +static bool is_us(const char *pid) { + pid_t t; + + assert(pid); + + if (parse_pid(pid, &t) < 0) + return false; + + return t == getpid(); +} + +static void dev_kmsg_record(Server *s, char *p, size_t l) { + struct iovec iovec[N_IOVEC_META_FIELDS + 7 + N_IOVEC_KERNEL_FIELDS + 2 + N_IOVEC_UDEV_FIELDS]; + char *message = NULL, *syslog_priority = NULL, *syslog_pid = NULL, *syslog_facility = NULL, *syslog_identifier = NULL, *source_time = NULL; + int priority, r; + unsigned n = 0, z = 0, j; + usec_t usec; + char *identifier = NULL, *pid = NULL, *e, *f, *k; + uint64_t serial; + size_t pl; + char *kernel_device = NULL; + + assert(s); + assert(p); + + if (l <= 0) + return; + + e = memchr(p, ',', l); + if (!e) + return; + *e = 0; + + r = safe_atoi(p, &priority); + if (r < 0 || priority < 0 || priority > 999) + return; + + if (s->forward_to_kmsg && (priority & LOG_FACMASK) != LOG_KERN) + return; + + l -= (e - p) + 1; + p = e + 1; + e = memchr(p, ',', l); + if (!e) + return; + *e = 0; + + r = safe_atou64(p, &serial); + if (r < 0) + return; + + if (s->kernel_seqnum) { + /* We already read this one? */ + if (serial < *s->kernel_seqnum) + return; + + /* Did we lose any? */ + if (serial > *s->kernel_seqnum) + server_driver_message(s, SD_MESSAGE_JOURNAL_MISSED, "Missed %llu kernel messages", (unsigned long long) serial - *s->kernel_seqnum - 1); + + /* Make sure we never read this one again. Note that + * we always store the next message serial we expect + * here, simply because this makes handling the first + * message with serial 0 easy. */ + *s->kernel_seqnum = serial + 1; + } + + l -= (e - p) + 1; + p = e + 1; + f = memchr(p, ';', l); + if (!f) + return; + /* Kernel 3.6 has the flags field, kernel 3.5 lacks that */ + e = memchr(p, ',', l); + if (!e || f < e) + e = f; + *e = 0; + + r = parse_usec(p, &usec); + if (r < 0) + return; + + l -= (f - p) + 1; + p = f + 1; + e = memchr(p, '\n', l); + if (!e) + return; + *e = 0; + + pl = e - p; + l -= (e - p) + 1; + k = e + 1; + + for (j = 0; l > 0 && j < N_IOVEC_KERNEL_FIELDS; j++) { + char *m; + /* Meta data fields attached */ + + if (*k != ' ') + break; + + k ++, l --; + + e = memchr(k, '\n', l); + if (!e) + return; + + *e = 0; + + m = cunescape_length_with_prefix(k, e - k, "_KERNEL_"); + if (!m) + break; + + if (startswith(m, "_KERNEL_DEVICE=")) + kernel_device = m + 15; + + IOVEC_SET_STRING(iovec[n++], m); + z++; + + l -= (e - k) + 1; + k = e + 1; + } + + if (kernel_device) { + struct udev_device *ud; + + ud = udev_device_new_from_device_id(s->udev, kernel_device); + if (ud) { + const char *g; + struct udev_list_entry *ll; + char *b; + + g = udev_device_get_devnode(ud); + if (g) { + b = strappend("_UDEV_DEVNODE=", g); + if (b) { + IOVEC_SET_STRING(iovec[n++], b); + z++; + } + } + + g = udev_device_get_sysname(ud); + if (g) { + b = strappend("_UDEV_SYSNAME=", g); + if (b) { + IOVEC_SET_STRING(iovec[n++], b); + z++; + } + } + + j = 0; + ll = udev_device_get_devlinks_list_entry(ud); + udev_list_entry_foreach(ll, ll) { + + if (j > N_IOVEC_UDEV_FIELDS) + break; + + g = udev_list_entry_get_name(ll); + b = strappend("_UDEV_DEVLINK=", g); + if (g) { + IOVEC_SET_STRING(iovec[n++], b); + z++; + } + + j++; + } + + udev_device_unref(ud); + } + } + + if (asprintf(&source_time, "_SOURCE_MONOTONIC_TIMESTAMP=%llu", + (unsigned long long) usec) >= 0) + IOVEC_SET_STRING(iovec[n++], source_time); + + IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=kernel"); + + if (asprintf(&syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK) >= 0) + IOVEC_SET_STRING(iovec[n++], syslog_priority); + + if ((priority & LOG_FACMASK) == LOG_KERN) + IOVEC_SET_STRING(iovec[n++], "SYSLOG_IDENTIFIER=kernel"); + else { + syslog_read_identifier((const char**) &p, &identifier, &pid); + + /* Avoid any messages we generated ourselves via + * log_info() and friends. */ + if (pid && is_us(pid)) + goto finish; + + if (identifier) { + syslog_identifier = strappend("SYSLOG_IDENTIFIER=", identifier); + if (syslog_identifier) + IOVEC_SET_STRING(iovec[n++], syslog_identifier); + } + + if (pid) { + syslog_pid = strappend("SYSLOG_PID=", pid); + if (syslog_pid) + IOVEC_SET_STRING(iovec[n++], syslog_pid); + } + + if (asprintf(&syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority)) >= 0) + IOVEC_SET_STRING(iovec[n++], syslog_facility); + } + + message = cunescape_length_with_prefix(p, pl, "MESSAGE="); + if (message) + IOVEC_SET_STRING(iovec[n++], message); + + server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, NULL, 0, NULL, priority); + +finish: + for (j = 0; j < z; j++) + free(iovec[j].iov_base); + + free(message); + free(syslog_priority); + free(syslog_identifier); + free(syslog_pid); + free(syslog_facility); + free(source_time); + free(identifier); + free(pid); +} + +int server_read_dev_kmsg(Server *s) { + char buffer[8192+1]; /* the kernel-side limit per record is 8K currently */ + ssize_t l; + + assert(s); + assert(s->dev_kmsg_fd >= 0); + + l = read(s->dev_kmsg_fd, buffer, sizeof(buffer) - 1); + if (l == 0) + return 0; + if (l < 0) { + /* Old kernels who don't allow reading from /dev/kmsg + * return EINVAL when we try. So handle this cleanly, + * but don' try to ever read from it again. */ + if (errno == EINVAL) { + epoll_ctl(s->epoll_fd, EPOLL_CTL_DEL, s->dev_kmsg_fd, NULL); + return 0; + } + + if (errno == EAGAIN || errno == EINTR || errno == EPIPE) + return 0; + + log_error("Failed to read from kernel: %m"); + return -errno; + } + + dev_kmsg_record(s, buffer, l); + return 1; +} + +int server_flush_dev_kmsg(Server *s) { + int r; + + assert(s); + + if (s->dev_kmsg_fd < 0) + return 0; + + if (!s->dev_kmsg_readable) + return 0; + + log_info("Flushing /dev/kmsg..."); + + for (;;) { + r = server_read_dev_kmsg(s); + if (r < 0) + return r; + + if (r == 0) + break; + } + + return 0; +} + +int server_open_dev_kmsg(Server *s) { + struct epoll_event ev; + + assert(s); + + s->dev_kmsg_fd = open("/dev/kmsg", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY); + if (s->dev_kmsg_fd < 0) { + log_warning("Failed to open /dev/kmsg, ignoring: %m"); + return 0; + } + + zero(ev); + ev.events = EPOLLIN; + ev.data.fd = s->dev_kmsg_fd; + if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->dev_kmsg_fd, &ev) < 0) { + + /* This will fail with EPERM on older kernels where + * /dev/kmsg is not readable. */ + if (errno == EPERM) + return 0; + + log_error("Failed to add /dev/kmsg fd to epoll object: %m"); + return -errno; + } + + s->dev_kmsg_readable = true; + + return 0; +} + +int server_open_kernel_seqnum(Server *s) { + int fd; + uint64_t *p; + + assert(s); + + /* We store the seqnum we last read in an mmaped file. That + * way we can just use it like a variable, but it is + * persistant and automatically flushed at reboot. */ + + fd = open("/run/systemd/journal/kernel-seqnum", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0644); + if (fd < 0) { + log_error("Failed to open /run/systemd/journal/kernel-seqnum, ignoring: %m"); + return 0; + } + + if (posix_fallocate(fd, 0, sizeof(uint64_t)) < 0) { + log_error("Failed to allocate sequential number file, ignoring: %m"); + close_nointr_nofail(fd); + return 0; + } + + p = mmap(NULL, sizeof(uint64_t), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); + if (p == MAP_FAILED) { + log_error("Failed to map sequential number file, ignoring: %m"); + close_nointr_nofail(fd); + return 0; + } + + close_nointr_nofail(fd); + s->kernel_seqnum = p; + + return 0; +} -- cgit v1.2.3-54-g00ecf