[Xen-devel] [PATCH] xenconsoled: don't force newline with timestamps

[Cole Robinson <crobinso@xxxxxxxxxx>]

The patch below changes xenconsoled to not force a newline at the end
of buffers being sent to timestamped logs.

Previously a newline was forced after every call to write_with_timestamp.
This could result in some ugly logs when a single console line stetched
over multiple calls. This change carries some extra state to determine if
we ended the last call to write_with_timestamp on a newline, and prints
the timestamp as appropriate.

This also fixes a bug where logging hv messages was dependent on the
guest timestamp flag.

Signed-off-by: Cole Robinson <crobinso@xxxxxxxxxx>


diff -r 8848d9e07584 tools/console/daemon/io.c
--- a/tools/console/daemon/io.c Mon Feb 18 21:26:57 2008 +0000
+++ b/tools/console/daemon/io.c Tue Feb 19 10:25:23 2008 -0500
@@ -64,6 +64,8 @@ extern int log_time_guest;
 extern int log_time_guest;
 extern char *log_dir;
 
+static int log_time_hv_needts = 1;
+static int log_time_guest_needts = 1;
 static int log_hv_fd = -1;
 static evtchn_port_or_error_t log_hv_evtchn = -1;
 static int xc_handle = -1;
@@ -116,30 +118,32 @@ static int write_all(int fd, const char*
        return 0;
 }
 
-static int write_with_timestamp(int fd, const char *data, size_t sz)
+static int write_with_timestamp(int fd, const char *data, size_t sz,
+                               int *needts)
 {
-       char buf[sz+1];
        char ts[32];
        time_t now = time(NULL);
        const struct tm *tmnow = localtime(&now);
        size_t tslen = strftime(ts, sizeof(ts), "[%Y-%m-%d %H:%M:%S] ", tmnow);
+       const char *last_byte = data + sz - 1;
 
-       memcpy(buf, data, sz);
-       while (sz > 0 && buf[sz-1] == '\r')
-               sz--;               // Don't print trailing \r's
-       if (sz > 0 && buf[sz-1] != '\n')
-               buf[sz++] = '\n';   // Force ending newline
-       data = buf;
+       while (data <= last_byte) {
+               const char *nl = memchr(data, '\n', sz);
+               int found_nl = (nl != NULL);
+               if (!found_nl)
+                       nl = last_byte;
 
-       while (sz > 0) {
-               const char *nl = strchr(data, '\n') + 1;
-               size_t towrite = nl - data;
-               if (write_all(fd, ts, tslen) < 0)
+               if ((*needts && write_all(fd, ts, tslen))
+                   || write_all(fd, data, nl + 1 - data))
                        return -1;
-               if (write_all(fd, data, towrite))
-                       return -1;
-               sz -= towrite;
-               data = nl;
+
+               *needts = found_nl;
+               data = nl + 1;
+               if (found_nl) {
+                       // If we printed a newline, strip all \r following it
+                       while (data <= last_byte && *data == '\r')
+                               data++;
+               }
        }
 
        return 0;
@@ -183,7 +187,7 @@ static void buffer_append(struct domain 
        if (dom->log_fd != -1) {
                int logret;
                if (log_time_guest) {
-                       logret = write_with_timestamp(dom->log_fd, buffer->data 
+ buffer->size - size, size);
+                       logret = write_with_timestamp(dom->log_fd, buffer->data 
+ buffer->size - size, size, &log_time_guest_needts);
                } else {
                        logret = write_all(dom->log_fd, buffer->data + 
buffer->size - size, size);
         }
@@ -246,7 +250,8 @@ static int create_hv_log(void)
                      logfile, errno, strerror(errno));
        if (fd != -1 && log_time_hv) {
                if (write_with_timestamp(fd, "Logfile Opened",
-                                        strlen("Logfile Opened")) < 0) {
+                                        strlen("Logfile Opened"),
+                                        &log_time_hv_needts) < 0) {
                        dolog(LOG_ERR, "Failed to log opening timestamp "
                                       "in %s: %d (%s)", logfile, errno,
                                       strerror(errno));
@@ -289,7 +294,8 @@ static int create_domain_log(struct doma
                      logfile, errno, strerror(errno));
        if (fd != -1 && log_time_guest) {
                if (write_with_timestamp(fd, "Logfile Opened",
-                                        strlen("Logfile Opened")) < 0) {
+                                        strlen("Logfile Opened"),
+                                        &log_time_guest_needts) < 0) {
                        dolog(LOG_ERR, "Failed to log opening timestamp "
                                       "in %s: %d (%s)", logfile, errno,
                                       strerror(errno));
@@ -886,8 +892,9 @@ static void handle_hv_logs(void)
 
        if (xc_readconsolering(xc_handle, &bufptr, &size, 0, 1, &index) == 0 && 
size > 0) {
                int logret;
-               if (log_time_guest)
-                       logret = write_with_timestamp(log_hv_fd, buffer, size);
+               if (log_time_hv)
+                       logret = write_with_timestamp(log_hv_fd, buffer, size,
+                                                     &log_time_hv_needts);
                else
                        logret = write_all(log_hv_fd, buffer, size);
 

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