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

qemu/aarch64.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_aarch64
 #define error_get_class error_get_class_aarch64
 #define error_get_pretty error_get_pretty_aarch64
-#define error_setg_file_open error_setg_file_open_aarch64
+#define error_setg_file_open_internal error_setg_file_open_internal_aarch64
 #define estimateDiv128To64 estimateDiv128To64_aarch64
 #define estimateSqrt32 estimateSqrt32_aarch64
 #define excnames excnames_aarch64

qemu/aarch64eb.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_aarch64eb
 #define error_get_class error_get_class_aarch64eb
 #define error_get_pretty error_get_pretty_aarch64eb
-#define error_setg_file_open error_setg_file_open_aarch64eb
+#define error_setg_file_open_internal error_setg_file_open_internal_aarch64eb
 #define estimateDiv128To64 estimateDiv128To64_aarch64eb
 #define estimateSqrt32 estimateSqrt32_aarch64eb
 #define excnames excnames_aarch64eb

qemu/arm.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_arm
 #define error_get_class error_get_class_arm
 #define error_get_pretty error_get_pretty_arm
-#define error_setg_file_open error_setg_file_open_arm
+#define error_setg_file_open_internal error_setg_file_open_internal_arm
 #define estimateDiv128To64 estimateDiv128To64_arm
 #define estimateSqrt32 estimateSqrt32_arm
 #define excnames excnames_arm

qemu/armeb.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_armeb
 #define error_get_class error_get_class_armeb
 #define error_get_pretty error_get_pretty_armeb
-#define error_setg_file_open error_setg_file_open_armeb
+#define error_setg_file_open_internal error_setg_file_open_internal_armeb
 #define estimateDiv128To64 estimateDiv128To64_armeb
 #define estimateSqrt32 estimateSqrt32_armeb
 #define excnames excnames_armeb

qemu/header_gen.py

@@ -397,7 +397,7 @@ symbols = (
     'error_exit',
     'error_get_class',
     'error_get_pretty',
-    'error_setg_file_open',
+    'error_setg_file_open_internal',
     'estimateDiv128To64',
     'estimateSqrt32',
     'excnames',

qemu/include/qapi/error.h

@@ -112,16 +112,27 @@ void error_set_errno(Error **errp, int os_error, ErrorClass err_class,
  * The new error's class is ERROR_CLASS_GENERIC_ERROR, and its
  * human-readable error message is made from printf-style @fmt, ...
  */
-void error_setg(Error **errp, const char *fmt, ...)
-    GCC_FMT_ATTR(2, 3);
+#define error_setg(errp, fmt, ...)                              \
+    error_setg_internal((errp), __FILE__, __LINE__, __func__,   \
+                        (fmt), ## __VA_ARGS__)
+void error_setg_internal(Error **errp,
+                         const char *src, int line, const char *func,
+                         const char *fmt, ...)
+    GCC_FMT_ATTR(5, 6);
 
 /*
  * Just like error_setg(), with @os_error info added to the message.
  * If @os_error is non-zero, ": " + strerror(os_error) is appended to
  * the human-readable error message.
  */
-void error_setg_errno(Error **errp, int os_error, const char *fmt, ...)
-    GCC_FMT_ATTR(3, 4);
+#define error_setg_errno(errp, os_error, fmt, ...)                      \
+    error_setg_errno_internal((errp), __FILE__, __LINE__, __func__,     \
+                              (os_error), (fmt), ## __VA_ARGS__)
+void error_setg_errno_internal(Error **errp,
+                               const char *fname, int line, const char *func,
+                               int os_error, const char *fmt, ...)
+    GCC_FMT_ATTR(6, 7);
+
 
 /*
  * Propagate error object (if any) from @local_err to @dst_errp.
@@ -141,7 +152,12 @@ void error_propagate(Error **dst_errp, Error *local_err);
 /**
  * Convenience function to report open() failure.
  */
-void error_setg_file_open(Error **errp, int os_errno, const char *filename);
+#define error_setg_file_open(errp, os_errno, filename)                  \
+    error_setg_file_open_internal((errp), __FILE__, __LINE__, __func__, \
+                                  (os_errno), (filename))
+void error_setg_file_open_internal(Error **errp,
+                                   const char *src, int line, const char *func,
+                                   int os_errno, const char *filename);
 
 /**
  * Return an exact copy of @err.
@@ -159,8 +175,13 @@ void error_free(Error *err);
  * Note: use of error classes other than ERROR_CLASS_GENERIC_ERROR is
  * strongly discouraged.
  */
-void error_set(Error **errp, ErrorClass err_class, const char *fmt, ...)
-    GCC_FMT_ATTR(3, 4);
+#define error_set(errp, err_class, fmt, ...)                    \
+    error_set_internal((errp), __FILE__, __LINE__, __func__,    \
+                       (err_class), (fmt), ## __VA_ARGS__)
+void error_set_internal(Error **errp,
+                        const char *src, int line, const char *func,
+                        ErrorClass err_class, const char *fmt, ...)
+    GCC_FMT_ATTR(6, 7);
 
 /*
  * Pass to error_setg() & friends to abort() on error.

qemu/m68k.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_m68k
 #define error_get_class error_get_class_m68k
 #define error_get_pretty error_get_pretty_m68k
-#define error_setg_file_open error_setg_file_open_m68k
+#define error_setg_file_open_internal error_setg_file_open_internal_m68k
 #define estimateDiv128To64 estimateDiv128To64_m68k
 #define estimateSqrt32 estimateSqrt32_m68k
 #define excnames excnames_m68k

qemu/mips.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_mips
 #define error_get_class error_get_class_mips
 #define error_get_pretty error_get_pretty_mips
-#define error_setg_file_open error_setg_file_open_mips
+#define error_setg_file_open_internal error_setg_file_open_internal_mips
 #define estimateDiv128To64 estimateDiv128To64_mips
 #define estimateSqrt32 estimateSqrt32_mips
 #define excnames excnames_mips

qemu/mips64.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_mips64
 #define error_get_class error_get_class_mips64
 #define error_get_pretty error_get_pretty_mips64
-#define error_setg_file_open error_setg_file_open_mips64
+#define error_setg_file_open_internal error_setg_file_open_internal_mips64
 #define estimateDiv128To64 estimateDiv128To64_mips64
 #define estimateSqrt32 estimateSqrt32_mips64
 #define excnames excnames_mips64

qemu/mips64el.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_mips64el
 #define error_get_class error_get_class_mips64el
 #define error_get_pretty error_get_pretty_mips64el
-#define error_setg_file_open error_setg_file_open_mips64el
+#define error_setg_file_open_internal error_setg_file_open_internal_mips64el
 #define estimateDiv128To64 estimateDiv128To64_mips64el
 #define estimateSqrt32 estimateSqrt32_mips64el
 #define excnames excnames_mips64el

qemu/mipsel.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_mipsel
 #define error_get_class error_get_class_mipsel
 #define error_get_pretty error_get_pretty_mipsel
-#define error_setg_file_open error_setg_file_open_mipsel
+#define error_setg_file_open_internal error_setg_file_open_internal_mipsel
 #define estimateDiv128To64 estimateDiv128To64_mipsel
 #define estimateSqrt32 estimateSqrt32_mipsel
 #define excnames excnames_mipsel

qemu/powerpc.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_powerpc
 #define error_get_class error_get_class_powerpc
 #define error_get_pretty error_get_pretty_powerpc
-#define error_setg_file_open error_setg_file_open_powerpc
+#define error_setg_file_open_internal error_setg_file_open_internal_powerpc
 #define estimateDiv128To64 estimateDiv128To64_powerpc
 #define estimateSqrt32 estimateSqrt32_powerpc
 #define excnames excnames_powerpc

qemu/sparc.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_sparc
 #define error_get_class error_get_class_sparc
 #define error_get_pretty error_get_pretty_sparc
-#define error_setg_file_open error_setg_file_open_sparc
+#define error_setg_file_open_internal error_setg_file_open_internal_sparc
 #define estimateDiv128To64 estimateDiv128To64_sparc
 #define estimateSqrt32 estimateSqrt32_sparc
 #define excnames excnames_sparc

qemu/sparc64.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_sparc64
 #define error_get_class error_get_class_sparc64
 #define error_get_pretty error_get_pretty_sparc64
-#define error_setg_file_open error_setg_file_open_sparc64
+#define error_setg_file_open_internal error_setg_file_open_internal_sparc64
 #define estimateDiv128To64 estimateDiv128To64_sparc64
 #define estimateSqrt32 estimateSqrt32_sparc64
 #define excnames excnames_sparc64

qemu/util/error.c

@@ -17,12 +17,24 @@ struct Error
 {
     char *msg;
     ErrorClass err_class;
+    const char *src, *func;
+    int line;
 };
 
 Error *error_abort;
 
-static void error_setv(Error **errp, ErrorClass err_class,
-                       const char *fmt, va_list ap)
+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;
@@ -36,9 +48,12 @@ static void error_setv(Error **errp, ErrorClass err_class,
 
     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) {
-        // abort();
+        error_do_abort(err);
     }
 
     *errp = err;
@@ -46,25 +61,31 @@ static void error_setv(Error **errp, ErrorClass err_class,
     errno = saved_errno;
 }
 
-void error_set(Error **errp, ErrorClass err_class, const char *fmt, ...)
+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, err_class, fmt, ap);
+    error_setv(errp, src, line, func, err_class, fmt, ap);
     va_end(ap);
 }
 
-void error_setg(Error **errp, const char *fmt, ...)
+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, ERROR_CLASS_GENERIC_ERROR, fmt, ap);
+    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap);
     va_end(ap);
 }
 
-void error_setg_errno(Error **errp, int os_errno, const char *fmt, ...)
+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;
@@ -75,7 +96,7 @@ void error_setg_errno(Error **errp, int os_errno, const char *fmt, ...)
     }
 
     va_start(ap, fmt);
-    error_setv(errp, ERROR_CLASS_GENERIC_ERROR, fmt, ap);
+    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap);
     va_end(ap);
 
     if (os_errno != 0) {
@@ -87,9 +108,12 @@ void error_setg_errno(Error **errp, int os_errno, const char *fmt, ...)
     errno = saved_errno;
 }
 
-void error_setg_file_open(Error **errp, int os_errno, const char *filename)
+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(errp, os_errno, "Could not open '%s'", filename);
+    error_setg_errno_internal(errp, src, line, func, os_errno,
+                              "Could not open '%s'", filename);
 }
 
 Error *error_copy(const Error *err)
@@ -124,7 +148,7 @@ void error_free(Error *err)
 void error_propagate(Error **dst_errp, Error *local_err)
 {
     if (local_err && dst_errp == &error_abort) {
-        // abort();
+        error_do_abort(local_err);
     } else if (dst_errp && !*dst_errp) {
         *dst_errp = local_err;
     } else if (local_err) {

qemu/x86_64.h

@@ -391,7 +391,7 @@
 #define error_exit error_exit_x86_64
 #define error_get_class error_get_class_x86_64
 #define error_get_pretty error_get_pretty_x86_64
-#define error_setg_file_open error_setg_file_open_x86_64
+#define error_setg_file_open_internal error_setg_file_open_internal_x86_64
 #define estimateDiv128To64 estimateDiv128To64_x86_64
 #define estimateSqrt32 estimateSqrt32_x86_64
 #define excnames excnames_x86_64