From 1e9b65bb1bad51735cab6c861c29b592dccabf0e Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Fri, 19 Jun 2015 19:21:59 +0200 Subject: 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__. Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Acked-by: Laszlo Ersek --- qga/vss-win32.c | 2 +- qga/vss-win32/requester.cpp | 5 +++-- qga/vss-win32/requester.h | 6 ++++-- 3 files changed, 8 insertions(+), 5 deletions(-) (limited to 'qga') diff --git a/qga/vss-win32.c b/qga/vss-win32.c index d75d7bbf09..2142b4964d 100644 --- a/qga/vss-win32.c +++ b/qga/vss-win32.c @@ -150,7 +150,7 @@ void qga_vss_fsfreeze(int *nr_volume, Error **errp, bool freeze) const char *func_name = freeze ? "requester_freeze" : "requester_thaw"; QGAVSSRequesterFunc func; ErrorSet errset = { - .error_setg_win32 = error_setg_win32, + .error_setg_win32 = error_setg_win32_internal, .errp = errp, }; diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp index aae0d5f2bf..9b3e310971 100644 --- a/qga/vss-win32/requester.cpp +++ b/qga/vss-win32/requester.cpp @@ -23,8 +23,9 @@ /* Call QueryStatus every 10 ms while waiting for frozen event */ #define VSS_TIMEOUT_EVENT_MSEC 10 -#define err_set(e, err, fmt, ...) \ - ((e)->error_setg_win32((e)->errp, err, fmt, ## __VA_ARGS__)) +#define err_set(e, err, fmt, ...) \ + ((e)->error_setg_win32((e)->errp, __FILE__, __LINE__, __func__, \ + err, fmt, ## __VA_ARGS__)) /* Bad idea, works only when (e)->errp != NULL: */ #define err_is_set(e) ((e)->errp && *(e)->errp) /* To lift this restriction, error_propagate(), like we do in QEMU code */ diff --git a/qga/vss-win32/requester.h b/qga/vss-win32/requester.h index 34be5c1d11..c3093cf4b6 100644 --- a/qga/vss-win32/requester.h +++ b/qga/vss-win32/requester.h @@ -23,8 +23,10 @@ extern "C" { struct Error; /* Callback to set Error; used to avoid linking glib to the DLL */ -typedef void (*ErrorSetFunc)(struct Error **errp, int win32_err, - const char *fmt, ...) GCC_FMT_ATTR(3, 4); +typedef void (*ErrorSetFunc)(struct Error **errp, + const char *src, int line, const char *func, + int win32_err, const char *fmt, ...) + GCC_FMT_ATTR(6, 7); typedef struct ErrorSet { ErrorSetFunc error_setg_win32; struct Error **errp; /* restriction: must not be null */ -- cgit v1.2.3