unicorn/qemu/util/error.c
Markus Armbruster 97ad660361
error: On abort, report where the error was created
This is particularly useful when we abort in error_propagate(),
because there the stack backtrace doesn't lead to where the error was
created. Looks like this:

Unexpected error in parse_block_error_action() at .../qemu/blockdev.c:322:
qemu-system-x86_64: -drive if=none,werror=foo: 'foo' invalid write error action
Aborted (core dumped)

Note: to get this example output, I monkey-patched drive_new() to pass
&error_abort to blockdev_init().

To keep the error handling boiler plate from growing even more, all
error_setFOO() become macros expanding into error_setFOO_internal()
with additional __FILE__, __LINE__, __func__ arguments. Not exactly
pretty, but it works.

The macro trickery breaks down when you take the address of an
error_setFOO(). Fortunately, we do that in just one place: qemu-ga's
Windows VSS provider and requester DLL wants to call
error_setg_win32() through a function pointer "to avoid linking glib
to the DLL". Use error_setg_win32_internal() there. The use of the
function pointer is already wrapped in a macro, so the churn isn't
bad.

Code size increases by some 35KiB for me (0.7%). Tolerable. Could be
less if we passed relative rather than absolute source file names to
the compiler, or forwent reporting __func__.

Backports commit 1e9b65bb1bad51735cab6c861c29b592dccabf0e from qemu
2018-02-17 15:23:37 -05:00

158 lines
3.4 KiB
C

/*
* QEMU Error Objects
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.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-common.h"
#include "qapi/error.h"
struct Error
{
char *msg;
ErrorClass err_class;
const char *src, *func;
int line;
};
Error *error_abort;
static void error_do_abort(Error *err)
{
fprintf(stderr, "Unexpected error in %s() at %s:%d:\n",
err->func, err->src, err->line);
// UNICORN: Commented out
// error_report_err(err);
// abort();
}
static void error_setv(Error **errp,
const char *src, int line, const char *func,
ErrorClass err_class, const char *fmt, va_list ap)
{
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);
err->err_class = err_class;
err->src = src;
err->line = line;
err->func = func;
if (errp == &error_abort) {
error_do_abort(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);
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);
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;
char *msg;
int saved_errno = errno;
if (errp == NULL) {
return;
}
va_start(ap, fmt);
error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap);
va_end(ap);
if (os_errno != 0) {
msg = (*errp)->msg;
(*errp)->msg = g_strdup_printf("%s: %s", msg, strerror(os_errno));
g_free(msg);
}
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);
}
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;
return err_new;
}
ErrorClass error_get_class(const Error *err)
{
return err->err_class;
}
const char *error_get_pretty(Error *err)
{
return err->msg;
}
void error_free(Error *err)
{
if (err) {
g_free(err->msg);
g_free(err);
}
}
void error_propagate(Error **dst_errp, Error *local_err)
{
if (local_err && dst_errp == &error_abort) {
error_do_abort(local_err);
} else if (dst_errp && !*dst_errp) {
*dst_errp = local_err;
} else if (local_err) {
error_free(local_err);
}
}