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authorLennart Poettering <lennart@poettering.net>2010-01-27 23:32:50 +0100
committerLennart Poettering <lennart@poettering.net>2010-01-27 23:32:50 +0100
commit4901f972785c4cd3a2cc10a8f4b6ce4e2ab3a568 (patch)
treee574830c97e2c6ed1ba4cb0997672ffe5960c990
parentb52429d4e0de52b89c7d043164aa1ac720e9179f (diff)
implement /dev/kmsg loggin
-rw-r--r--logger.c123
1 files changed, 93 insertions, 30 deletions
diff --git a/logger.c b/logger.c
index c7c4cb83d2..cd2970002c 100644
--- a/logger.c
+++ b/logger.c
@@ -11,6 +11,7 @@
#include <sys/poll.h>
#include <sys/epoll.h>
#include <sys/un.h>
+#include <fcntl.h>
#include "util.h"
#include "log.h"
@@ -25,7 +26,8 @@
typedef struct Stream Stream;
typedef struct Server {
- int log_fd;
+ int syslog_fd;
+ int kmsg_fd;
int epoll_fd;
unsigned n_server_fd;
@@ -35,25 +37,33 @@ typedef struct Server {
} Server;
typedef enum StreamState {
+ STREAM_LOG_TARGET,
STREAM_PRIORITY,
STREAM_PROCESS,
STREAM_RUNNING
} StreamState;
+typedef enum LogTarget {
+ LOG_TARGET_SYSLOG,
+ LOG_TARGET_KMSG
+} LogTarget;
+
struct Stream {
Server *server;
StreamState state;
int fd;
+
+ LogTarget target;
int priority;
char *process;
+ pid_t pid;
+ uid_t uid;
char buffer[STREAM_BUFFER];
size_t length;
- pid_t pid;
-
LIST_FIELDS(Stream, stream);
};
@@ -66,8 +76,6 @@ struct Stream {
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];
@@ -78,37 +86,62 @@ static int stream_log(Stream *s, char *p, usec_t timestamp) {
return 0;
/*
- * The format glibc uses is:
+ * The format glibc uses to talk to the syslog daemon is:
+ *
+ * <priority>time process[pid]: msg
*
- * <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->priority);
+ snprintf(header_priority, sizeof(header_priority), "<%i>",
+ s->target == LOG_TARGET_SYSLOG ? s->priority : LOG_PRI(s->priority));
char_array_0(header_priority);
- t = (time_t) (timestamp / USEC_PER_SEC);
- if (!(tm = localtime(&t)))
- return -EINVAL;
+ if (s->target == LOG_TARGET_SYSLOG) {
+ time_t t;
+ struct tm *tm;
- if (strftime(header_time, sizeof(header_time), "%h %e %T ", tm) <= 0)
- return -EINVAL;
+ 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 (s->target == LOG_TARGET_SYSLOG) {
+ 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);
- if (sendmsg(s->server->log_fd, &msghdr, MSG_NOSIGNAL) < 0)
- return -errno;
+ 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 == LOG_TARGET_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], "\n");
+
+ if (writev(s->server->kmsg_fd, iovec, ELEMENTSOF(iovec)) < 0)
+ return -errno;
+ } else
+ assert_not_reached("Unknown log target");
return 0;
}
@@ -123,12 +156,34 @@ static int stream_line(Stream *s, char *p, usec_t timestamp) {
switch (s->state) {
+ case STREAM_LOG_TARGET:
+ if (streq(p, "syslog"))
+ s->target = LOG_TARGET_SYSLOG;
+ else if (streq(p, "kmsg")) {
+
+ if (s->server->kmsg_fd >= 0 && s->uid == 0)
+ s->target = LOG_TARGET_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)
+ 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)
+ if (s->priority < 0) {
+ log_warning("Log priority negative: %s", strerror(errno));
return -ERANGE;
+ }
s->state = STREAM_PROCESS;
return 0;
@@ -271,6 +326,7 @@ static int stream_new(Server *s, int server_fd) {
}
stream->pid = ucred.pid;
+ stream->uid = ucred.uid;
stream->server = s;
LIST_PREPEND(Stream, stream, s->streams, stream);
@@ -336,11 +392,14 @@ static void server_done(Server *s) {
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->syslog_fd >= 0)
+ assert_se(close_nointr(s->syslog_fd) == 0);
if (s->epoll_fd >= 0)
assert_se(close_nointr(s->epoll_fd) == 0);
+
+ if (s->kmsg_fd >= 0)
+ assert_se(close_nointr(s->kmsg_fd) == 0);
}
static int server_init(Server *s, unsigned n_sockets) {
@@ -357,7 +416,8 @@ static int server_init(Server *s, unsigned n_sockets) {
zero(*s);
s->n_server_fd = n_sockets;
- s->log_fd = -1;
+ s->syslog_fd = -1;
+ s->kmsg_fd = -1;
if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) {
r = -errno;
@@ -378,7 +438,7 @@ static int server_init(Server *s, unsigned n_sockets) {
}
}
- if ((s->log_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) {
+ 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;
@@ -388,12 +448,16 @@ static int server_init(Server *s, unsigned n_sockets) {
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) {
+ 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:
@@ -463,7 +527,6 @@ int main(int argc, char *argv[]) {
if (server_init(&server, n) < 0)
return 2;
-
for (;;) {
struct epoll_event event;
int n;