Re: [Qemu-devel] [RFC][PATCH 07/10] virtagent: add getdmesg RPC

[Anthony Liguori]

On 10/22/2010 01:46 PM, Michael Roth wrote:

Add RPC to view guest dmesg output.

Signed-off-by: Michael Roth<mdr...@linux.vnet.ibm.com>
---
  virtagent-daemon.c |   45 +++++++++++++++++++++++++++++++++++++++++++++
  virtagent-daemon.h |    1 +
  2 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/virtagent-daemon.c b/virtagent-daemon.c
index fad0f64..6aaa987 100644
--- a/virtagent-daemon.c
+++ b/virtagent-daemon.c
@@ -72,6 +72,48 @@ EXIT_CLOSE_BAD:
      return result;
  }

+/* getdmesg(): return dmesg output
+ * rpc return values:
+ *   - dmesg output as a string
+ */
+static xmlrpc_value *getdmesg(xmlrpc_env *env,
+                              xmlrpc_value *param,
+                              void *user_data)
+{
+    char *dmesg_buf = NULL, cmd[256];
+    char c;
+    int pos = 0;
+    xmlrpc_value *result = NULL;
+    FILE *pipe;
+
+    dmesg_buf = qemu_mallocz(VA_DMESG_LEN + 2048);
+    sprintf(cmd, "dmesg -s %d", VA_DMESG_LEN);
+
+    //pipe = popen(cmd, "r");
+    pipe = popen("dmesg -s 16000", "r");
+    if (pipe == NULL) {
+        LOG("popen failed: %s", strerror(errno));
+        xmlrpc_faultf(env, "popen failed: %s", strerror(errno));
+        goto EXIT_NOCLOSE;
+    }
+
+    while ((c = fgetc(pipe)) != EOF&&  pos<  VA_DMESG_LEN) {
+        dmesg_buf[pos] = c;
+        pos++;
+    }

fgetc seems a bit odd here.  Why not fread?

Regards,

Anthony Liguori

+    dmesg_buf[pos++] = '\0';
+    TRACE("dmesg:\n%s", dmesg_buf);
+
+    result = xmlrpc_build_value(env, "s", dmesg_buf);
+    pclose(pipe);
+EXIT_NOCLOSE:
+    if (dmesg_buf) {
+        qemu_free(dmesg_buf);
+    }
+
+    return result;
+}
+
  static int va_accept(int listen_fd) {
      struct sockaddr_in saddr;
      struct sockaddr *addr;
@@ -101,6 +143,8 @@ typedef struct RPCFunction {
  static RPCFunction guest_functions[] = {
      { .func = getfile,
        .func_name = "getfile" },
+    { .func = getdmesg,
+      .func_name = "getdmesg" },
      { NULL, NULL }
  };
  static RPCFunction host_functions[] = {
@@ -165,6 +209,7 @@ int va_server_loop(int listen_fd, bool is_host)
          XMLRPC_MEMBLOCK_FREE(char, rpc_response);
  out:
          closesocket(fd);
+        xmlrpc_env_clean(&env);
      }

      return 0;
diff --git a/virtagent-daemon.h b/virtagent-daemon.h
index bb197d0..adcbc9a 100644
--- a/virtagent-daemon.h
+++ b/virtagent-daemon.h
@@ -16,5 +16,6 @@
  #define HOST_AGENT_PATH "/tmp/virtagent-host.sock"
  #define VA_GETFILE_MAX 1<<  30
  #define VA_FILEBUF_LEN 16384
+#define VA_DMESG_LEN 16384

  int va_server_loop(int listen_fd, bool is_host);