[Qemu-devel] [PATCH v2 0/3] Clean up non-blocking error reporting

[Qemu-devel] [PATCH v2 0/3] Clean up non-blocking error reporting

[minyard]

This version makes the error message reporting more sane and
adds a error_vreport() to make that easier.

It also cleans up the bool handling.

This depends on the previos non-blocking socket changes, which
should hopefully be in qemu soon.

[Qemu-devel] [PATCH 1/3] qemu-error: Add error_vreport()

[minyard]

From: Corey Minyard <cminyard@mvista.com>

Needed to nicely print socket error reports.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
 include/qemu/error-report.h |  1 +
 util/qemu-error.c           | 23 ++++++++++++++++++-----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
index 000eae3..7ab2355 100644
--- a/include/qemu/error-report.h
+++ b/include/qemu/error-report.h
@@ -38,6 +38,7 @@ void error_vprintf(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
 void error_printf(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 void error_printf_unless_qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 void error_set_progname(const char *argv0);
+void error_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
 void error_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 const char *error_get_progname(void);
 extern bool enable_timestamp_msg;
diff --git a/util/qemu-error.c b/util/qemu-error.c
index 7b167fd..9bba5f5 100644
--- a/util/qemu-error.c
+++ b/util/qemu-error.c
@@ -199,14 +199,13 @@ static void error_print_loc(void)
 bool enable_timestamp_msg;
 /*
  * Print an error message to current monitor if we have one, else to stderr.
- * Format arguments like sprintf().  The result should not contain
+ * Format arguments like vsprintf().  The result should not contain
  * newlines.
  * Prepend the current location and append a newline.
  * It's wrong to call this in a QMP monitor.  Use qerror_report() there.
  */
-void error_report(const char *fmt, ...)
+void error_vreport(const char *fmt, va_list ap)
 {
-    va_list ap;
     GTimeVal tv;
     gchar *timestr;
 
@@ -218,8 +217,22 @@ void error_report(const char *fmt, ...)
     }
 
     error_print_loc();
-    va_start(ap, fmt);
     error_vprintf(fmt, ap);
-    va_end(ap);
     error_printf("\n");
 }
+
+/*
+ * Print an error message to current monitor if we have one, else to stderr.
+ * Format arguments like sprintf().  The result should not contain
+ * newlines.
+ * Prepend the current location and append a newline.
+ * It's wrong to call this in a QMP monitor.  Use qerror_report() there.
+ */
+void error_report(const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    error_vreport(fmt, ap);
+    va_end(ap);
+}
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH 1/3] qemu-error: Add error_vreport()

[Eric Blake]

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On 10/08/2014 06:11 AM, minyard@acm.org wrote:
> From: Corey Minyard <cminyard@mvista.com>
> 
> Needed to nicely print socket error reports.
> 
> Signed-off-by: Corey Minyard <cminyard@mvista.com>
> ---
>  include/qemu/error-report.h |  1 +
>  util/qemu-error.c           | 23 ++++++++++++++++++-----
>  2 files changed, 19 insertions(+), 5 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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[Qemu-devel] [PATCH 2/3] qemu-char: Fix reconnect socket error reporting

[minyard]

From: Corey Minyard <cminyard@mvista.com>

If reconnect was set, errors wouldn't always be reported.
Fix that and also only report a connect error once until a
connection has been made.

The primary purpose of this is to tell the user that a
connection failed so they can know they need to figure out
what went wrong.  So we don't want to spew too much
out here, just enough so they know.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
 qemu-char.c | 57 ++++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 42 insertions(+), 15 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 62af0ef..83ff458 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2509,6 +2509,7 @@ typedef struct {
 
     guint reconnect_timer;
     int64_t reconnect_time;
+    bool connect_err_reported;
 } TCPCharDriver;
 
 static gboolean socket_reconnect_timeout(gpointer opaque);
@@ -2521,6 +2522,24 @@ static void qemu_chr_socket_restart_timer(CharDriverState *chr)
                                                socket_reconnect_timeout, chr);
 }
 
+static void check_report_connect_error(CharDriverState *chr,
+                                       const char *fmt, ...) GCC_FMT_ATTR(2, 3);
+
+static void check_report_connect_error(CharDriverState *chr,
+                                       const char *fmt, ...)
+{
+    TCPCharDriver *s = chr->opaque;
+
+    if (!s->connect_err_reported) {
+        va_list ap;
+        va_start(ap, fmt);
+        error_vreport(fmt, ap);
+        va_end(ap);
+        s->connect_err_reported = true;
+    }
+    qemu_chr_socket_restart_timer(chr);
+}
+
 static gboolean tcp_chr_accept(GIOChannel *chan, GIOCondition cond, void *opaque);
 
 #ifndef _WIN32
@@ -3045,12 +3064,15 @@ static void qemu_chr_finish_socket_connection(CharDriverState *chr, int fd)
 static void qemu_chr_socket_connected(int fd, void *opaque)
 {
     CharDriverState *chr = opaque;
+    TCPCharDriver *s = chr->opaque;
 
     if (fd < 0) {
-        qemu_chr_socket_restart_timer(chr);
+        check_report_connect_error(chr, "Unable to connect to socket %s",
+                                   chr->label);
         return;
     }
 
+    s->connect_err_reported = false;
     qemu_chr_finish_socket_connection(chr, fd);
 }
 
@@ -4066,11 +4088,21 @@ static CharDriverState *qmp_chardev_open_parallel(ChardevHostdev *parallel,
 
 #endif /* WIN32 */
 
+static void socket_try_connect(CharDriverState *chr)
+{
+    Error *err = NULL;
+
+    if (!qemu_chr_open_socket_fd(chr, &err)) {
+        check_report_connect_error(chr,
+                                   "Unable to start connect to socket %s: %s",
+                                   chr->label, error_get_pretty(err));
+    }
+}
+
 static gboolean socket_reconnect_timeout(gpointer opaque)
 {
     CharDriverState *chr = opaque;
     TCPCharDriver *s = chr->opaque;
-    Error *err;
 
     s->reconnect_timer = 0;
 
@@ -4078,10 +4110,7 @@ static gboolean socket_reconnect_timeout(gpointer opaque)
         return false;
     }
 
-    if (!qemu_chr_open_socket_fd(chr, &err)) {
-        error_report("Unable to connect to char device %s\n", chr->label);
-        qemu_chr_socket_restart_timer(chr);
-    }
+    socket_try_connect(chr);
 
     return false;
 }
@@ -4133,15 +4162,13 @@ static CharDriverState *qmp_chardev_open_socket(ChardevSocket *sock,
         s->reconnect_time = reconnect;
     }
 
-    if (!qemu_chr_open_socket_fd(chr, errp)) {
-        if (s->reconnect_time) {
-            qemu_chr_socket_restart_timer(chr);
-        } else {
-            g_free(s);
-            g_free(chr->filename);
-            g_free(chr);
-            return NULL;
-        }
+    if (s->reconnect_time) {
+        socket_try_connect(chr);
+    } else if (!qemu_chr_open_socket_fd(chr, errp)) {
+        g_free(s);
+        g_free(chr->filename);
+        g_free(chr);
+        return NULL;
     }
 
     if (is_listen && is_waitconnect) {
-- 
1.8.3.1

[Qemu-devel] [PATCH 3/3] qemu-sockets: Add error to non-blocking connect handler

[minyard]

From: Corey Minyard <cminyard@mvista.com>

An error value here would be quite handy and more consistent
with the rest of the code.

Corey Minyard <cminyard@mvista.com>
---
 include/qemu/sockets.h |  2 +-
 migration-tcp.c        |  4 ++--
 migration-unix.c       |  4 ++--
 qemu-char.c            |  6 +++---
 util/qemu-sockets.c    | 19 ++++++++++++++-----
 5 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
index fdbb196..f47dae6 100644
--- a/include/qemu/sockets.h
+++ b/include/qemu/sockets.h
@@ -47,7 +47,7 @@ int recv_all(int fd, void *buf, int len1, bool single_read);
 /* callback function for nonblocking connect
  * valid fd on success, negative error code on failure
  */
-typedef void NonBlockingConnectHandler(int fd, void *opaque);
+typedef void NonBlockingConnectHandler(int fd, Error *errp, void *opaque);
 
 InetSocketAddress *inet_parse(const char *str, Error **errp);
 int inet_listen_opts(QemuOpts *opts, int port_offset, Error **errp);
diff --git a/migration-tcp.c b/migration-tcp.c
index 2e34517..91c9cf3 100644
--- a/migration-tcp.c
+++ b/migration-tcp.c
@@ -33,12 +33,12 @@
     do { } while (0)
 #endif
 
-static void tcp_wait_for_connect(int fd, void *opaque)
+static void tcp_wait_for_connect(int fd, Error *err, void *opaque)
 {
     MigrationState *s = opaque;
 
     if (fd < 0) {
-        DPRINTF("migrate connect error\n");
+        DPRINTF("migrate connect error: %s\n", error_get_pretty(err));
         s->file = NULL;
         migrate_fd_error(s);
     } else {
diff --git a/migration-unix.c b/migration-unix.c
index 0a5f8a1..1cdadfb 100644
--- a/migration-unix.c
+++ b/migration-unix.c
@@ -33,12 +33,12 @@
     do { } while (0)
 #endif
 
-static void unix_wait_for_connect(int fd, void *opaque)
+static void unix_wait_for_connect(int fd, Error *err, void *opaque)
 {
     MigrationState *s = opaque;
 
     if (fd < 0) {
-        DPRINTF("migrate connect error\n");
+        DPRINTF("migrate connect error: %s\n", error_get_pretty(err));
         s->file = NULL;
         migrate_fd_error(s);
     } else {
diff --git a/qemu-char.c b/qemu-char.c
index 83ff458..8f3af06 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3061,14 +3061,14 @@ static void qemu_chr_finish_socket_connection(CharDriverState *chr, int fd)
     }
 }
 
-static void qemu_chr_socket_connected(int fd, void *opaque)
+static void qemu_chr_socket_connected(int fd, Error *err, void *opaque)
 {
     CharDriverState *chr = opaque;
     TCPCharDriver *s = chr->opaque;
 
     if (fd < 0) {
-        check_report_connect_error(chr, "Unable to connect to socket %s",
-                                   chr->label);
+        check_report_connect_error(chr, "Unable to connect to socket %s: %s",
+                                   chr->label, error_get_pretty(err));
         return;
     }
 
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index 1eef590..e6a9644 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -234,6 +234,7 @@ static void wait_for_connect(void *opaque)
     int val = 0, rc = 0;
     socklen_t valsize = sizeof(val);
     bool in_progress;
+    Error *err = NULL;
 
     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 
@@ -248,6 +249,7 @@ static void wait_for_connect(void *opaque)
 
     /* connect error */
     if (rc < 0) {
+        error_setg_errno(&err, errno, "Error connecting to socket");
         closesocket(s->fd);
         s->fd = rc;
     }
@@ -257,9 +259,14 @@ static void wait_for_connect(void *opaque)
         while (s->current_addr->ai_next != NULL && s->fd < 0) {
             s->current_addr = s->current_addr->ai_next;
             s->fd = inet_connect_addr(s->current_addr, &in_progress, s, NULL);
+            if (s->fd < 0) {
+                error_free(err);
+                err = NULL;
+                error_setg_errno(&err, errno, "Unable to start socket connect");
+            }
             /* connect in progress */
             if (in_progress) {
-                return;
+                goto out;
             }
         }
 
@@ -267,9 +274,11 @@ static void wait_for_connect(void *opaque)
     }
 
     if (s->callback) {
-        s->callback(s->fd, s->opaque);
+        s->callback(s->fd, err, s->opaque);
     }
     g_free(s);
+out:
+    error_free(err);
 }
 
 static int inet_connect_addr(struct addrinfo *addr, bool *in_progress,
@@ -401,7 +410,7 @@ int inet_connect_opts(QemuOpts *opts, Error **errp,
         return sock;
     } else {
         if (callback) {
-            callback(sock, opaque);
+            callback(sock, NULL, opaque);
         }
     }
     g_free(connect_state);
@@ -769,7 +778,7 @@ int unix_connect_opts(QemuOpts *opts, Error **errp,
     } else if (rc >= 0) {
         /* non blocking socket immediate success, call callback */
         if (callback != NULL) {
-            callback(sock, opaque);
+            callback(sock, NULL, opaque);
         }
     }
 
@@ -919,7 +928,7 @@ int socket_connect(SocketAddress *addr, Error **errp,
         fd = monitor_get_fd(cur_mon, addr->fd->str, errp);
         if (fd >= 0 && callback) {
             qemu_set_nonblock(fd);
-            callback(fd, opaque);
+            callback(fd, NULL, opaque);
         }
         break;
 
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH 3/3] qemu-sockets: Add error to non-blocking connect handler

[Paolo Bonzini]

Il 08/10/2014 14:11, minyard@acm.org ha scritto:
> From: Corey Minyard <cminyard@mvista.com>
> 
> An error value here would be quite handy and more consistent
> with the rest of the code.
> 
> Corey Minyard <cminyard@mvista.com>
> ---
>  include/qemu/sockets.h |  2 +-
>  migration-tcp.c        |  4 ++--
>  migration-unix.c       |  4 ++--
>  qemu-char.c            |  6 +++---
>  util/qemu-sockets.c    | 19 ++++++++++++++-----
>  5 files changed, 22 insertions(+), 13 deletions(-)
> 
> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
> index fdbb196..f47dae6 100644
> --- a/include/qemu/sockets.h
> +++ b/include/qemu/sockets.h
> @@ -47,7 +47,7 @@ int recv_all(int fd, void *buf, int len1, bool single_read);
>  /* callback function for nonblocking connect
>   * valid fd on success, negative error code on failure
>   */
> -typedef void NonBlockingConnectHandler(int fd, void *opaque);
> +typedef void NonBlockingConnectHandler(int fd, Error *errp, void *opaque);
>  
>  InetSocketAddress *inet_parse(const char *str, Error **errp);
>  int inet_listen_opts(QemuOpts *opts, int port_offset, Error **errp);
> diff --git a/migration-tcp.c b/migration-tcp.c
> index 2e34517..91c9cf3 100644
> --- a/migration-tcp.c
> +++ b/migration-tcp.c
> @@ -33,12 +33,12 @@
>      do { } while (0)
>  #endif
>  
> -static void tcp_wait_for_connect(int fd, void *opaque)
> +static void tcp_wait_for_connect(int fd, Error *err, void *opaque)
>  {
>      MigrationState *s = opaque;
>  
>      if (fd < 0) {
> -        DPRINTF("migrate connect error\n");
> +        DPRINTF("migrate connect error: %s\n", error_get_pretty(err));
>          s->file = NULL;
>          migrate_fd_error(s);
>      } else {
> diff --git a/migration-unix.c b/migration-unix.c
> index 0a5f8a1..1cdadfb 100644
> --- a/migration-unix.c
> +++ b/migration-unix.c
> @@ -33,12 +33,12 @@
>      do { } while (0)
>  #endif
>  
> -static void unix_wait_for_connect(int fd, void *opaque)
> +static void unix_wait_for_connect(int fd, Error *err, void *opaque)
>  {
>      MigrationState *s = opaque;
>  
>      if (fd < 0) {
> -        DPRINTF("migrate connect error\n");
> +        DPRINTF("migrate connect error: %s\n", error_get_pretty(err));
>          s->file = NULL;
>          migrate_fd_error(s);
>      } else {
> diff --git a/qemu-char.c b/qemu-char.c
> index 83ff458..8f3af06 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -3061,14 +3061,14 @@ static void qemu_chr_finish_socket_connection(CharDriverState *chr, int fd)
>      }
>  }
>  
> -static void qemu_chr_socket_connected(int fd, void *opaque)
> +static void qemu_chr_socket_connected(int fd, Error *err, void *opaque)
>  {
>      CharDriverState *chr = opaque;
>      TCPCharDriver *s = chr->opaque;
>  
>      if (fd < 0) {
> -        check_report_connect_error(chr, "Unable to connect to socket %s",
> -                                   chr->label);
> +        check_report_connect_error(chr, "Unable to connect to socket %s: %s",
> +                                   chr->label, error_get_pretty(err));
>          return;
>      }
>  
> diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
> index 1eef590..e6a9644 100644
> --- a/util/qemu-sockets.c
> +++ b/util/qemu-sockets.c
> @@ -234,6 +234,7 @@ static void wait_for_connect(void *opaque)
>      int val = 0, rc = 0;
>      socklen_t valsize = sizeof(val);
>      bool in_progress;
> +    Error *err = NULL;
>  
>      qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
>  
> @@ -248,6 +249,7 @@ static void wait_for_connect(void *opaque)
>  
>      /* connect error */
>      if (rc < 0) {
> +        error_setg_errno(&err, errno, "Error connecting to socket");
>          closesocket(s->fd);
>          s->fd = rc;
>      }

This is missing above this hunk:

diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index e6a9644..a76bb3c 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -245,6 +245,7 @@ static void wait_for_connect(void *opaque)
     /* update rc to contain error */
     if (!rc && val) {
         rc = -1;
+        errno = val;
     }

     /* connect error */

> @@ -257,9 +259,14 @@ static void wait_for_connect(void *opaque)
>          while (s->current_addr->ai_next != NULL && s->fd < 0) {
>              s->current_addr = s->current_addr->ai_next;
>              s->fd = inet_connect_addr(s->current_addr, &in_progress, s, NULL);
> +            if (s->fd < 0) {
> +                error_free(err);
> +                err = NULL;
> +                error_setg_errno(&err, errno, "Unable to start socket connect");
> +            }
>              /* connect in progress */
>              if (in_progress) {
> -                return;
> +                goto out;
>              }
>          }
>  
> @@ -267,9 +274,11 @@ static void wait_for_connect(void *opaque)
>      }
>  
>      if (s->callback) {
> -        s->callback(s->fd, s->opaque);
> +        s->callback(s->fd, err, s->opaque);
>      }
>      g_free(s);
> +out:
> +    error_free(err);
>  }
>  
>  static int inet_connect_addr(struct addrinfo *addr, bool *in_progress,
> @@ -401,7 +410,7 @@ int inet_connect_opts(QemuOpts *opts, Error **errp,
>          return sock;
>      } else {
>          if (callback) {
> -            callback(sock, opaque);
> +            callback(sock, NULL, opaque);
>          }
>      }
>      g_free(connect_state);
> @@ -769,7 +778,7 @@ int unix_connect_opts(QemuOpts *opts, Error **errp,
>      } else if (rc >= 0) {
>          /* non blocking socket immediate success, call callback */
>          if (callback != NULL) {
> -            callback(sock, opaque);
> +            callback(sock, NULL, opaque);
>          }
>      }
>  
> @@ -919,7 +928,7 @@ int socket_connect(SocketAddress *addr, Error **errp,
>          fd = monitor_get_fd(cur_mon, addr->fd->str, errp);
>          if (fd >= 0 && callback) {
>              qemu_set_nonblock(fd);
> -            callback(fd, opaque);
> +            callback(fd, NULL, opaque);
>          }
>          break;
>  
> 

Re: [Qemu-devel] [PATCH 3/3] qemu-sockets: Add error to non-blocking connect handler

[Corey Minyard]

On 10/09/2014 05:07 AM, Paolo Bonzini wrote:
>> +        error_setg_errno(&err, errno, "Error connecting to socket");
>> >          closesocket(s->fd);
>> >          s->fd = rc;
>> >      }
> This is missing above this hunk:
>
> diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
> index e6a9644..a76bb3c 100644
> --- a/util/qemu-sockets.c
> +++ b/util/qemu-sockets.c
> @@ -245,6 +245,7 @@ static void wait_for_connect(void *opaque)
>      /* update rc to contain error */
>      if (!rc && val) {
>          rc = -1;
> +        errno = val;
>      }
>
>      /* connect error */
>

Yes, it is.  I see that everything went in, thanks for your work on this.

Now on to IPMI...

-corey

Re: [Qemu-devel] [PATCH v2 0/3] Clean up non-blocking error reporting

[Paolo Bonzini]

Il 08/10/2014 14:11, minyard@acm.org ha scritto:
> This version makes the error message reporting more sane and
> adds a error_vreport() to make that easier.
> 
> It also cleans up the bool handling.
> 
> This depends on the previos non-blocking socket changes, which
> should hopefully be in qemu soon.

Looks good, but let's unify the error message like this:

+static void check_report_connect_error(CharDriverState *chr,
+                                       Error *err)
+{
+    TCPCharDriver *s = chr->opaque;
+
+    if (!s->connect_err_reported) {
+        error_report("Unable to connect character device %s: %s",
+                     chr->label, error_get_pretty(err));
+        s->connect_err_reported = true;
+    }
+    qemu_chr_socket_restart_timer(chr);
+}
+

This is an error on connecting the character device to the backend.  The
error on the socket is already detailed after the colon, thanks to your
patch 2.

I'll send a pull request today or tomorrow.

Thanks,

Paolo