From 50b7b000c9171c1253c1c875f46f654c3c0e1fc8 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Thu, 10 Sep 2015 10:19:16 -0600 Subject: [PATCH] hmp: Allow for error message hints on HMP Commits 7216ae3d and d2828429 disabled some error message hints, all because a change to use modern error reporting meant that the hint would be output prior to the actual error. Fix this by making hints a first-class member of Error. For example, we are now back to the pleasant: $ qemu-system-x86_64 --nodefaults -S --vnc :0 --chardev null,id=, qemu-system-x86_64: --chardev null,id=,: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. Signed-off-by: Eric Blake Reviewed-by: Paolo Bonzini Message-Id: <1441901956-21991-1-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster --- include/qapi/error.h | 7 +++++++ qdev-monitor.c | 42 ++++++++++++++---------------------------- util/error.c | 32 ++++++++++++++++++++++++++++++++ util/qemu-option.c | 11 ++++------- 4 files changed, 57 insertions(+), 35 deletions(-) diff --git a/include/qapi/error.h b/include/qapi/error.h index 426d5eaceb..d7878c3088 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -155,6 +155,13 @@ void error_setg_win32_internal(Error **errp, */ void error_propagate(Error **dst_errp, Error *local_err); +/** + * Append a printf-style human-readable explanation to an existing error. + * May be called multiple times, and safe if @errp is NULL. + */ +void error_append_hint(Error **errp, const char *fmt, ...) + GCC_FMT_ATTR(2, 3); + /* * Convenience function to report open() failure. */ diff --git a/qdev-monitor.c b/qdev-monitor.c index f9e2d6258d..0bf7f83a1d 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -289,37 +289,35 @@ static Object *qdev_get_peripheral_anon(void) return dev; } -#if 0 /* conversion from qerror_report() to error_set() broke their use */ -static void qbus_list_bus(DeviceState *dev) +static void qbus_list_bus(DeviceState *dev, Error **errp) { BusState *child; const char *sep = " "; - error_printf("child buses at \"%s\":", - dev->id ? dev->id : object_get_typename(OBJECT(dev))); + error_append_hint(errp, "child buses at \"%s\":", + dev->id ? dev->id : object_get_typename(OBJECT(dev))); QLIST_FOREACH(child, &dev->child_bus, sibling) { - error_printf("%s\"%s\"", sep, child->name); + error_append_hint(errp, "%s\"%s\"", sep, child->name); sep = ", "; } - error_printf("\n"); } -static void qbus_list_dev(BusState *bus) +static void qbus_list_dev(BusState *bus, Error **errp) { BusChild *kid; const char *sep = " "; - error_printf("devices at \"%s\":", bus->name); + error_append_hint(errp, "devices at \"%s\":", bus->name); QTAILQ_FOREACH(kid, &bus->children, sibling) { DeviceState *dev = kid->child; - error_printf("%s\"%s\"", sep, object_get_typename(OBJECT(dev))); - if (dev->id) - error_printf("/\"%s\"", dev->id); + error_append_hint(errp, "%s\"%s\"", sep, + object_get_typename(OBJECT(dev))); + if (dev->id) { + error_append_hint(errp, "/\"%s\"", dev->id); + } sep = ", "; } - error_printf("\n"); } -#endif static BusState *qbus_find_bus(DeviceState *dev, char *elem) { @@ -461,11 +459,7 @@ static BusState *qbus_find(const char *path, Error **errp) if (!dev) { error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, "Device '%s' not found", elem); -#if 0 /* conversion from qerror_report() to error_set() broke this: */ - if (!monitor_cur_is_qmp()) { - qbus_list_dev(bus); - } -#endif + qbus_list_dev(bus, errp); return NULL; } @@ -483,11 +477,7 @@ static BusState *qbus_find(const char *path, Error **errp) if (dev->num_child_bus) { error_setg(errp, "Device '%s' has multiple child buses", elem); -#if 0 /* conversion from qerror_report() to error_set() broke this: */ - if (!monitor_cur_is_qmp()) { - qbus_list_bus(dev); - } -#endif + qbus_list_bus(dev, errp); } else { error_setg(errp, "Device '%s' has no child bus", elem); } @@ -503,11 +493,7 @@ static BusState *qbus_find(const char *path, Error **errp) bus = qbus_find_bus(dev, elem); if (!bus) { error_setg(errp, "Bus '%s' not found", elem); -#if 0 /* conversion from qerror_report() to error_set() broke this: */ - if (!monitor_cur_is_qmp()) { - qbus_list_bus(dev); - } -#endif + qbus_list_bus(dev, errp); return NULL; } } diff --git a/util/error.c b/util/error.c index cdb726ce81..9dd474f3be 100644 --- a/util/error.c +++ b/util/error.c @@ -20,6 +20,7 @@ struct Error ErrorClass err_class; const char *src, *func; int line; + GString *hint; }; Error *error_abort; @@ -115,6 +116,28 @@ void error_setg_file_open_internal(Error **errp, "Could not open '%s'", filename); } +void error_append_hint(Error **errp, const char *fmt, ...) +{ + va_list ap; + int saved_errno = errno; + Error *err; + + if (!errp) { + return; + } + err = *errp; + assert(err && errp != &error_abort); + + if (!err->hint) { + err->hint = g_string_new(NULL); + } + va_start(ap, fmt); + g_string_append_vprintf(err->hint, fmt, ap); + va_end(ap); + + errno = saved_errno; +} + #ifdef _WIN32 void error_setg_win32_internal(Error **errp, @@ -151,6 +174,9 @@ Error *error_copy(const Error *err) err_new = g_malloc0(sizeof(*err)); err_new->msg = g_strdup(err->msg); err_new->err_class = err->err_class; + if (err->hint) { + err_new->hint = g_string_new(err->hint->str); + } return err_new; } @@ -168,6 +194,9 @@ const char *error_get_pretty(Error *err) void error_report_err(Error *err) { error_report("%s", error_get_pretty(err)); + if (err->hint) { + error_printf_unless_qmp("%s\n", err->hint->str); + } error_free(err); } @@ -175,6 +204,9 @@ void error_free(Error *err) { if (err) { g_free(err->msg); + if (err->hint) { + g_string_free(err->hint, true); + } g_free(err); } } diff --git a/util/qemu-option.c b/util/qemu-option.c index b1fb57c0fc..a50eceae4a 100644 --- a/util/qemu-option.c +++ b/util/qemu-option.c @@ -205,10 +205,8 @@ void parse_option_size(const char *name, const char *value, break; default: error_setg(errp, QERR_INVALID_PARAMETER_VALUE, name, "a size"); -#if 0 /* conversion from qerror_report() to error_set() broke this: */ - error_printf_unless_qmp("You may use k, M, G or T suffixes for " - "kilobytes, megabytes, gigabytes and terabytes.\n"); -#endif + error_append_hint(errp, "You may use k, M, G or T suffixes for " + "kilobytes, megabytes, gigabytes and terabytes."); return; } } else { @@ -648,9 +646,8 @@ QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id, if (!id_wellformed(id)) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "id", "an identifier"); -#if 0 /* conversion from qerror_report() to error_set() broke this: */ - error_printf_unless_qmp("Identifiers consist of letters, digits, '-', '.', '_', starting with a letter.\n"); -#endif + error_append_hint(errp, "Identifiers consist of letters, digits, " + "'-', '.', '_', starting with a letter."); return NULL; } opts = qemu_opts_find(list, id);