Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 305 insertions, 0 deletions

diff --git a/util/error.c b/util/error.c
new file mode 100644
index 000000000..b6c89d141
--- /dev/null
+++ b/util/error.c
@@ -0,0 +1,305 @@
+/*
+ * QEMU Error Objects
+ *
+ * Copyright IBM, Corp. 2011
+ * Copyright (C) 2011-2015 Red Hat, Inc.
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *  Markus Armbruster <armbru@redhat.com>,
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.  See
+ * the COPYING.LIB file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+
+struct Error
+{
+    char *msg;
+    ErrorClass err_class;
+    const char *src, *func;
+    int line;
+    GString *hint;
+};
+
+Error *error_abort;
+Error *error_fatal;
+
+static void error_handle_fatal(Error **errp, Error *err)
+{
+    if (errp == &error_abort) {
+        fprintf(stderr, "Unexpected error in %s() at %s:%d:\n",
+                err->func, err->src, err->line);
+        error_report("%s", error_get_pretty(err));
+        if (err->hint) {
+            error_printf("%s", err->hint->str);
+        }
+        abort();
+    }
+    if (errp == &error_fatal) {
+        error_report_err(err);
+        exit(1);
+    }
+}
+
+static void error_setv(Error **errp,
+                       const char *src, int line, const char *func,
+                       ErrorClass err_class, const char *fmt, va_list ap,
+                       const char *suffix)
+{
+    Error *err;
+    int saved_errno = errno;
+
+    if (errp == NULL) {
+        return;
+    }
+    assert(*errp == NULL);
+
+    err = g_malloc0(sizeof(*err));
+    err->msg = g_strdup_vprintf(fmt, ap);
+    if (suffix) {
+        char *msg = err->msg;
+        err->msg = g_strdup_printf("%s: %s", msg, suffix);
+        g_free(msg);
+    }
+    err->err_class = err_class;
+    err->src = src;
+    err->line = line;
+    err->func = func;
+
+    error_handle_fatal(errp, err);
+    *errp = err;
+
+    errno = saved_errno;
+}
+
+void error_set_internal(Error **errp,
+                        const char *src, int line, const char *func,
+                        ErrorClass err_class, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    error_setv(errp, src, line, func, err_class, fmt, ap, NULL);
+    va_end(ap);
+}
+
+void error_setg_internal(Error **errp,
+                         const char *src, int line, const char *func,
+                         const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap, NULL);
+    va_end(ap);
+}
+
+void error_setg_errno_internal(Error **errp,
+                               const char *src, int line, const char *func,
+                               int os_errno, const char *fmt, ...)
+{
+    va_list ap;
+    int saved_errno = errno;
+
+    va_start(ap, fmt);
+    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap,
+               os_errno != 0 ? strerror(os_errno) : NULL);
+    va_end(ap);
+
+    errno = saved_errno;
+}
+
+void error_setg_file_open_internal(Error **errp,
+                                   const char *src, int line, const char *func,
+                                   int os_errno, const char *filename)
+{
+    error_setg_errno_internal(errp, src, line, func, os_errno,
+                              "Could not open '%s'", filename);
+}
+
+void error_vprepend(Error *const *errp, const char *fmt, va_list ap)
+{
+    GString *newmsg;
+
+    if (!errp) {
+        return;
+    }
+
+    newmsg = g_string_new(NULL);
+    g_string_vprintf(newmsg, fmt, ap);
+    g_string_append(newmsg, (*errp)->msg);
+    g_free((*errp)->msg);
+    (*errp)->msg = g_string_free(newmsg, 0);
+}
+
+void error_prepend(Error *const *errp, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    error_vprepend(errp, fmt, ap);
+    va_end(ap);
+}
+
+void error_append_hint(Error *const *errp, const char *fmt, ...)
+{
+    va_list ap;
+    int saved_errno = errno;
+    Error *err;
+
+    if (!errp) {
+        return;
+    }
+    err = *errp;
+    assert(err && errp != &error_abort && errp != &error_fatal);
+
+    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,
+                               const char *src, int line, const char *func,
+                               int win32_err, const char *fmt, ...)
+{
+    va_list ap;
+    char *suffix = NULL;
+
+    if (errp == NULL) {
+        return;
+    }
+
+    if (win32_err != 0) {
+        suffix = g_win32_error_message(win32_err);
+    }
+
+    va_start(ap, fmt);
+    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR,
+               fmt, ap, suffix);
+    va_end(ap);
+
+    g_free(suffix);
+}
+
+#endif
+
+Error *error_copy(const Error *err)
+{
+    Error *err_new;
+
+    err_new = g_malloc0(sizeof(*err));
+    err_new->msg = g_strdup(err->msg);
+    err_new->err_class = err->err_class;
+    err_new->src = err->src;
+    err_new->line = err->line;
+    err_new->func = err->func;
+    if (err->hint) {
+        err_new->hint = g_string_new(err->hint->str);
+    }
+
+    return err_new;
+}
+
+ErrorClass error_get_class(const Error *err)
+{
+    return err->err_class;
+}
+
+const char *error_get_pretty(const Error *err)
+{
+    return err->msg;
+}
+
+void error_report_err(Error *err)
+{
+    error_report("%s", error_get_pretty(err));
+    if (err->hint) {
+        error_printf("%s", err->hint->str);
+    }
+    error_free(err);
+}
+
+void warn_report_err(Error *err)
+{
+    warn_report("%s", error_get_pretty(err));
+    if (err->hint) {
+        error_printf("%s", err->hint->str);
+    }
+    error_free(err);
+}
+
+void error_reportf_err(Error *err, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    error_vprepend(&err, fmt, ap);
+    va_end(ap);
+    error_report_err(err);
+}
+
+
+void warn_reportf_err(Error *err, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    error_vprepend(&err, fmt, ap);
+    va_end(ap);
+    warn_report_err(err);
+}
+
+void error_free(Error *err)
+{
+    if (err) {
+        g_free(err->msg);
+        if (err->hint) {
+            g_string_free(err->hint, true);
+        }
+        g_free(err);
+    }
+}
+
+void error_free_or_abort(Error **errp)
+{
+    assert(errp && *errp);
+    error_free(*errp);
+    *errp = NULL;
+}
+
+void error_propagate(Error **dst_errp, Error *local_err)
+{
+    if (!local_err) {
+        return;
+    }
+    error_handle_fatal(dst_errp, local_err);
+    if (dst_errp && !*dst_errp) {
+        *dst_errp = local_err;
+    } else {
+        error_free(local_err);
+    }
+}
+
+void error_propagate_prepend(Error **dst_errp, Error *err,
+                             const char *fmt, ...)
+{
+    va_list ap;
+
+    if (dst_errp && !*dst_errp) {
+        va_start(ap, fmt);
+        error_vprepend(&err, fmt, ap);
+        va_end(ap);
+    } /* else error is being ignored, don't bother with prepending */
+    error_propagate(dst_errp, err);
+}