xen/log-guest-console.patch

Add code to support logging xen-domU console, as what xenconsoled does. Log info
will be saved in /var/log/xen/console/guest-domUname.log.

Signed-off-by: Chunyan Liu <cyliu@novell.com>
---
 hw/xen_console.c |   71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 71 insertions(+), 0 deletions(-)

Index: xen-4.2.0-testing/tools/qemu-xen-traditional-dir-remote/hw/xen_console.c
===================================================================
--- xen-4.2.0-testing.orig/tools/qemu-xen-traditional-dir-remote/hw/xen_console.c
+++ xen-4.2.0-testing/tools/qemu-xen-traditional-dir-remote/hw/xen_console.c
@@ -38,6 +38,8 @@
 #include "qemu-char.h"
 #include "xen_backend.h"
 
+static int log_guest = 0;
+
 struct buffer {
     uint8_t *data;
     size_t consumed;
@@ -54,8 +56,24 @@ struct XenConsole {
     void              *sring;
     CharDriverState   *chr;
     int               backlog;
+    int               log_fd;
 };
 
+static int write_all(int fd, const char* buf, size_t len)
+{
+    while (len) {
+        ssize_t ret = write(fd, buf, len);
+        if (ret == -1 && errno == EINTR)
+            continue;
+        if (ret < 0)
+            return -1;
+        len -= ret;
+        buf += ret;
+    }
+
+    return 0;
+}
+
 static void buffer_append(struct XenConsole *con)
 {
     struct buffer *buffer = &con->buffer;
@@ -83,6 +101,15 @@ static void buffer_append(struct XenCons
     intf->out_cons = cons;
     xen_be_send_notify(&con->xendev);
 
+    if (con->log_fd != -1) {
+        int logret;
+        logret = write_all(con->log_fd, buffer->data + buffer->size - size, size);
+        if (logret < 0) {
+            xen_be_printf(&con->xendev, 1, "Write to log failed on domain %d: %d (%s)\n",
+                      con->xendev.dom, errno, strerror(errno));
+        }
+     }
+
     if (buffer->max_capacity &&
 	buffer->size > buffer->max_capacity) {
 	/* Discard the middle of the data. */
@@ -176,6 +203,37 @@ static void xencons_send(struct XenConso
     }
 }
 
+static int create_domain_log(struct XenConsole *con)
+{
+    char *logfile;
+    char *path, *domname;
+    int fd;
+    const char *logdir = "/var/log/xen/console";
+
+    path = xs_get_domain_path(xenstore, con->xendev.dom);
+    domname = xenstore_read_str(path, "name");
+    free(path);
+    if (!domname)
+        return -1;
+
+    if (mkdir(logdir, 0755) && errno != EEXIST)
+    {
+        xen_be_printf(&con->xendev, 1,  "Directory %s does not exist and fail to create it!", logdir);
+        return -1;
+    }
+
+    if (asprintf(&logfile, "%s/guest-%s.log", logdir, domname) < 0)
+        return -1;
+    qemu_free(domname);
+
+    fd = open(logfile, O_WRONLY|O_CREAT|O_APPEND, 0644);
+    free(logfile);
+    if (fd == -1)
+        xen_be_printf(&con->xendev, 1,  "Failed to open log %s: %d (%s)", logfile, errno, strerror(errno));
+
+    return fd;
+}
+
 /* -------------------------------------------------------------------- */
 
 static int con_init(struct XenDevice *xendev)
@@ -183,6 +241,7 @@ static int con_init(struct XenDevice *xe
     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
     char *type, *dom, label[32];
     const char *output;
+    char *logenv = NULL;
 
     /* setup */
     dom = xs_get_domain_path(xenstore, con->xendev.dom);
@@ -209,6 +268,10 @@ static int con_init(struct XenDevice *xe
 	con->chr = qemu_chr_open(label, output, NULL);
 	xenstore_store_pv_console_info(con->xendev.dev, con->chr, output);
 
+    logenv = getenv("XENCONSOLED_TRACE");
+    if (logenv != NULL && strlen(logenv) == strlen("guest") && !strcmp(logenv, "guest")) {
+        log_guest = 1;
+    }
     return 0;
 }
 
@@ -246,6 +309,9 @@ static int con_initialise(struct XenDevi
 		  con->xendev.remote_port,
 		  con->xendev.local_port,
 		  con->buffer.max_capacity);
+    con->log_fd = -1;
+    if (log_guest)
+         con->log_fd = create_domain_log(con);
     return 0;
 }
 
@@ -266,6 +332,12 @@ static void con_disconnect(struct XenDev
             xc_gnttab_munmap(xendev->gnttabdev, con->sring, 1);
 	con->sring = NULL;
     }
+
+    if (con->log_fd != -1) {
+        close(con->log_fd);
+        con->log_fd = -1;
+    }
+
 }
 
 static void con_event(struct XenDevice *xendev)