Changeset be3ad87 in code for logger.c

Timestamp:

Mar 7, 2014, 2:14:54 PM (11 years ago)

Author:

Mike Belopuhov <mike@…>

Branches:

master

Children:

e13307d

Parents:

460786f

Message:

Rewrite logger_dispatch to use bufferevents to simplify error processing

This also ensures that we're dealing with partial messages correctly and
don't get out of sync with the main process.

File:

• logger.c (modified) (4 diffs)

logger.c

@@ -37 +37 @@
 #include "icbd.h"
 
-void logger_dispatch(int, short, void *);
+void logger_ioerr(struct bufferevent *, short, void *);
+void logger_dispatch(struct bufferevent *, void *);
 FILE *logger_open(char *);
 void logger_tick(void);
@@ -65 +66 @@
 logger_init(void)
 {
-        static struct event ev;
+        struct bufferevent *bev;
         struct passwd *pw;
         int pipes[2];
@@ -117 +118 @@
 
         /* event for message processing */
-        event_set(&ev, pipes[1], EV_READ | EV_PERSIST, logger_dispatch, NULL);
-        if (event_add(&ev, NULL) < 0) {
-                syslog(LOG_ERR, "event_add: %m");
-                exit (EX_UNAVAILABLE);
+        if ((bev = bufferevent_new(pipes[1], logger_dispatch, NULL,
+            logger_ioerr, NULL)) == NULL) {
+                syslog(LOG_ERR, "bufferevent_new: %m");
+                exit(EX_UNAVAILABLE);
+        }
+        if (bufferevent_enable(bev, EV_READ)) {
+                syslog(LOG_ERR, "bufferevent_enable: %m");
+                bufferevent_free(bev);
+                exit(EX_UNAVAILABLE);
         }
 
@@ -129 +135 @@
 
 void
-logger_dispatch(int fd, short event, void *arg __attribute__((unused)))
-{
-        char buf[ICB_MSGSIZE];
-        struct icbd_logentry e;
-        struct iovec iov[2];
+logger_ioerr(struct bufferevent *bev __attribute__((__unused__)), short what,
+    void *arg __attribute__((__unused__)))
+{
+        const char *cause = NULL;
+
+        if (what & EVBUFFER_TIMEOUT)
+                cause = "timeout";
+        else if (what & EVBUFFER_EOF)
+                cause = "eof";
+        else if (what & EVBUFFER_ERROR)
+                cause = what & EVBUFFER_READ ? "read" : "write";
+        syslog(LOG_ERR, "logger_ioerr: %s", cause ? cause : "unknown");
+        exit(EX_IOERR);
+}
+
+void
+logger_dispatch(struct bufferevent *bev, void *arg __attribute__((unused)))
+{
+        struct icbd_logentry *e;
+        static char buf[sizeof *e + ICB_MSGSIZE];
+        static size_t nread = 0;
         FILE *fp = NULL;
+        size_t res;
+        char *m;
         int i;
 
-        if (event != EV_READ)
-                return;
-
-        bzero(&e, sizeof e);
-        iov[0].iov_base = &e;
-        iov[0].iov_len = sizeof e;
-
-        iov[1].iov_base = buf;
-        iov[1].iov_len = sizeof buf;
-
-        if (readv(fd, iov, 2) < (ssize_t)sizeof e) {
-                syslog(LOG_ERR, "logger read: %m");
-                exit(EX_DATAERR);
-        }
-
-        /* XXX */
-        if (iov[1].iov_len < e.length) {
-                syslog(LOG_ERR, "logger read %lu out of %lu",
-                    iov[1].iov_len, e.length);
-        }
-
-        for (i = 0; i < nlogfiles; i++)
-                if (strcmp(logfiles[i].group, e.group) == 0)
-                        fp = logfiles[i].fp;
-        if (!fp && (fp = logger_open(e.group)) == NULL)
-                return;
-        if (strlen(e.nick) == 0)
-                fprintf(fp, "[%s] %s\n", line_ts, buf);
-        else
-                fprintf(fp, "[%s] <%s> %s\n", line_ts, e.nick, buf);
+        e = (struct icbd_logentry *)buf;
+        m = buf + sizeof *e;
+
+        while (EVBUFFER_LENGTH(EVBUFFER_INPUT(bev)) > 0) {
+                if (nread == 0) {
+                        bzero(e, sizeof *e);
+                        /* read the log entry header */
+                        res = bufferevent_read(bev, &buf[0], sizeof *e);
+                        nread += res;
+                        if (nread < sizeof *e)
+                                return;
+                }
+                /* see if we got the whole header */
+                if (nread < sizeof *e) {
+                        /* finish reading */
+                        res = bufferevent_read(bev, &buf[nread],
+                            sizeof *e - nread);
+                        nread += res;
+                        if (nread < sizeof *e)
+                                return;
+                }
+                /* fetch the message */
+                res = bufferevent_read(bev, &buf[nread],
+                    MIN(e->length, ICB_MSGSIZE));
+                nread += res;
+#ifdef DEBUG
+                {
+                        printf("logger read %lu out of %lu:\n", res, e->length);
+                        for (i = 0; i < (int)res; i++)
+                                printf(" %02x", (unsigned char)m[i]);
+                        printf("\n");
+                }
+#endif
+                if (nread < e->length)
+                        return;
+                /* terminate the buffer */
+                m[MIN(nread - sizeof *e, ICB_MSGSIZE)] = '\0';
+                /* find the appropriate log file */
+                for (i = 0; i < nlogfiles; i++)
+                        if (strcmp(logfiles[i].group, e->group) == 0)
+                                fp = logfiles[i].fp;
+                if (!fp && (fp = logger_open(e->group)) == NULL)
+                        return;
+                if (strlen(e->nick) == 0)
+                        fprintf(fp, "[%s] %s\n", line_ts, m);
+                else
+                        fprintf(fp, "[%s] <%s> %s\n", line_ts, e->nick, m);
+                /* get ready for the next message */
+                nread = 0;
+        }
 }