| Message ID | 20200317151625.20797-3-vsementsov@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | error: auto propagated local_err part I | expand |
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> writes: > Script adds ERRP_AUTO_PROPAGATE macro invocation where appropriate and > does corresponding changes in code (look for details in > include/qapi/error.h) > > Usage example: > spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \ > --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff \ > --max-width 80 FILES... > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > > Cc: Eric Blake <eblake@redhat.com> > Cc: Kevin Wolf <kwolf@redhat.com> > Cc: Max Reitz <mreitz@redhat.com> > Cc: Greg Kurz <groug@kaod.org> > Cc: Christian Schoenebeck <qemu_oss@crudebyte.com> > Cc: Stefan Hajnoczi <stefanha@redhat.com> > Cc: Stefano Stabellini <sstabellini@kernel.org> > Cc: Anthony Perard <anthony.perard@citrix.com> > Cc: Paul Durrant <paul@xen.org> > Cc: "Philippe Mathieu-Daudé" <philmd@redhat.com> > Cc: Laszlo Ersek <lersek@redhat.com> > Cc: Gerd Hoffmann <kraxel@redhat.com> > Cc: Stefan Berger <stefanb@linux.ibm.com> > Cc: Markus Armbruster <armbru@redhat.com> > Cc: Michael Roth <mdroth@linux.vnet.ibm.com> > Cc: qemu-devel@nongnu.org > Cc: qemu-block@nongnu.org > Cc: xen-devel@lists.xenproject.org > > scripts/coccinelle/auto-propagated-errp.cocci | 336 ++++++++++++++++++ > include/qapi/error.h | 3 + > MAINTAINERS | 1 + > 3 files changed, 340 insertions(+) > create mode 100644 scripts/coccinelle/auto-propagated-errp.cocci > > diff --git a/scripts/coccinelle/auto-propagated-errp.cocci b/scripts/coccinelle/auto-propagated-errp.cocci > new file mode 100644 > index 0000000000..5188b07006 > --- /dev/null > +++ b/scripts/coccinelle/auto-propagated-errp.cocci > @@ -0,0 +1,336 @@ > +// Use ERRP_AUTO_PROPAGATE (see include/qapi/error.h) > +// > +// Copyright (c) 2020 Virtuozzo International GmbH. > +// > +// This program is free software; you can redistribute it and/or > +// modify it under the terms of the GNU General Public License as > +// published by the Free Software Foundation; either version 2 of the > +// License, or (at your option) any later version. > +// > +// This program is distributed in the hope that it will be useful, > +// but WITHOUT ANY WARRANTY; without even the implied warranty of > +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > +// GNU General Public License for more details. > +// > +// You should have received a copy of the GNU General Public License > +// along with this program. If not, see > +// <http://www.gnu.org/licenses/>. > +// > +// Usage example: > +// spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \ > +// --macro-file scripts/cocci-macro-file.h --in-place \ > +// --no-show-diff --max-width 80 FILES... > +// > +// Note: --max-width 80 is needed because coccinelle default is less > +// than 80, and without this parameter coccinelle may reindent some > +// lines which fit into 80 characters but not to coccinelle default, > +// which in turn produces extra patch hunks for no reason. > + > +// Switch unusual Error ** parameter names to errp > +// (this is necessary to use ERRP_AUTO_PROPAGATE). > +// > +// Disable optional_qualifier to skip functions with > +// "Error *const *errp" parameter. > +// > +// Skip functions with "assert(_errp && *_errp)" statement, because > +// that signals unusual semantics, and the parameter name may well > +// serve a purpose. (like nbd_iter_channel_error()). > +// > +// Skip util/error.c to not touch, for example, error_propagate() and > +// error_propagate_prepend(). > +@ depends on !(file in "util/error.c") disable optional_qualifier@ > +identifier fn; > +identifier _errp != errp; > +@@ > + > + fn(..., > +- Error **_errp > ++ Error **errp > + ,...) > + { > +( > + ... when != assert(_errp && *_errp) > +& > + <... > +- _errp > ++ errp > + ...> > +) > + } > + > +// Add invocation of ERRP_AUTO_PROPAGATE to errp-functions where > +// necessary > +// > +// Note, that without "when any" the final "..." does not mach > +// something matched by previous pattern, i.e. the rule will not match > +// double error_prepend in control flow like in > +// vfio_set_irq_signaling(). > +// > +// Note, "exists" says that we want apply rule even if it does not > +// match on all possible control flows (otherwise, it will not match > +// standard pattern when error_propagate() call is in if branch). > +@ disable optional_qualifier exists@ > +identifier fn, local_err; > +symbol errp; > +@@ > + > + fn(..., Error **errp, ...) > + { > ++ ERRP_AUTO_PROPAGATE(); > + ... when != ERRP_AUTO_PROPAGATE(); > +( > +( > + error_append_hint(errp, ...); > +| > + error_prepend(errp, ...); > +| > + error_vprepend(errp, ...); > +) > + ... when any > +| > + Error *local_err = NULL; > + ... > +( > + error_propagate_prepend(errp, local_err, ...); > +| > + error_propagate(errp, local_err); > +) > + ... > +) > + } > + > +// Warn when several Error * definitions are in the control flow. > +// This rule is not chained to rule1 and less restrictive, to cover more > +// functions to warn (even those we are not going to convert). > +// > +// Note, that even with one (or zero) Error * definition in the each > +// control flow we may have several (in total) Error * definitions in > +// the function. This case deserves attention too, but I don't see > +// simple way to match with help of coccinelle. > +@check1 disable optional_qualifier exists@ > +identifier fn, _errp, local_err, local_err2; > +position p1, p2; > +@@ > + > + fn(..., Error **_errp, ...) > + { > + ... > + Error *local_err = NULL;@p1 > + ... when any > + Error *local_err2 = NULL;@p2 > + ... when any > + } > + > +@ script:python @ > +fn << check1.fn; > +p1 << check1.p1; > +p2 << check1.p2; > +@@ > + > +print('Warning: function {} has several definitions of ' > + 'Error * local variable: at {}:{} and then at {}:{}'.format( > + fn, p1[0].file, p1[0].line, p2[0].file, p2[0].line)) > + > +// Warn when several propagations are in the control flow. > +@check2 disable optional_qualifier exists@ > +identifier fn, _errp; > +position p1, p2; > +@@ > + > + fn(..., Error **_errp, ...) > + { > + ... > +( > + error_propagate_prepend(_errp, ...);@p1 > +| > + error_propagate(_errp, ...);@p1 > +) > + ... > +( > + error_propagate_prepend(_errp, ...);@p2 > +| > + error_propagate(_errp, ...);@p2 > +) > + ... when any > + } > + > +@ script:python @ > +fn << check2.fn; > +p1 << check2.p1; > +p2 << check2.p2; > +@@ > + > +print('Warning: function {} propagates to errp several times in ' > + 'one control flow: at {}:{} and then at {}:{}'.format( > + fn, p1[0].file, p1[0].line, p2[0].file, p2[0].line)) > + > +// Match functions with propagation of local error to errp. > +// We want to refer these functions in several following rules, but I > +// don't know a proper way to inherit a function, not just its name > +// (to not match another functions with same name in following rules). > +// Not-proper way is as follows: rename errp parameter in functions > +// header and match it in following rules. Rename it back after all > +// transformations. > +// > +// The common case is a single definition of local_err with at most one > +// error_propagate_prepend() or error_propagate() on each control-flow > +// path. Functions with multiple definitions or propagates we want to > +// examine manually. Later rules emit warnings to guide us to them. "Later rules" is no longer correct. Suggest "Rules check1 and check2". > +// > +// Note that we match not only this "common case", but any function, > +// which has the "common cose" on at least one control-flow path. I appreciate this note. Typo: s/cose/case/ > +@rule1 disable optional_qualifier exists@ > +identifier fn, local_err; > +symbol errp; > +@@ > + > + fn(..., Error ** > +- errp > ++ ____ > + , ...) > + { > + ... > + Error *local_err = NULL; > + ... > +( > + error_propagate_prepend(errp, local_err, ...); > +| > + error_propagate(errp, local_err); > +) > + ... > + } > + > +// Convert special case with goto separately. > +// I tried merging this into the following rule the obvious way, but > +// it made Coccinelle hang on block.c > +// > +// Note interesting thing: if we don't do it here, and try to fixup > +// "out: }" things later after all transformations (the rule will be > +// the same, just without error_propagate() call), coccinelle fails to > +// match this "out: }". > +@ disable optional_qualifier@ > +identifier rule1.fn, rule1.local_err, out; > +symbol errp; > +@@ > + > + fn(..., Error ** ____, ...) > + { > + <... > +- goto out; > ++ return; > + ...> > +- out: > +- error_propagate(errp, local_err); > + } > + > +// Convert most of local_err related stuff. > +// > +// Note, that we inherit rule1.fn and rule1.local_err names, not > +// objects themselves. We may match something not related to the > +// pattern matched by rule1. For example, local_err may be defined with > +// the same name in different blocks inside one function, and in one > +// block follow the propagation pattern and in other block doesn't. > +// > +// Note also that errp-cleaning functions > +// error_free_errp > +// error_report_errp > +// error_reportf_errp > +// warn_report_errp > +// warn_reportf_errp > +// are not yet implemented. They must call corresponding Error* - > +// freeing function and then set *errp to NULL, to avoid further > +// propagation to original errp (consider ERRP_AUTO_PROPAGATE in use). > +// For example, error_free_errp may look like this: > +// > +// void error_free_errp(Error **errp) > +// { > +// error_free(*errp); > +// *errp = NULL; > +// } > +@ disable optional_qualifier exists@ > +identifier rule1.fn, rule1.local_err; > +expression list args; > +symbol errp; > +@@ > + > + fn(..., Error ** ____, ...) > + { > + <... > +( > +- Error *local_err = NULL; > +| > + > +// Convert error clearing functions > +( > +- error_free(local_err); > ++ error_free_errp(errp); > +| > +- error_report_err(local_err); > ++ error_report_errp(errp); > +| > +- error_reportf_err(local_err, args); > ++ error_reportf_errp(errp, args); > +| > +- warn_report_err(local_err); > ++ warn_report_errp(errp); > +| > +- warn_reportf_err(local_err, args); > ++ warn_reportf_errp(errp, args); > +) > +?- local_err = NULL; > + > +| > +- error_propagate_prepend(errp, local_err, args); > ++ error_prepend(errp, args); > +| > +- error_propagate(errp, local_err); > +| > +- &local_err > ++ errp > +) > + ...> > + } > + > +// Convert remaining local_err usage. For example, different kinds of > +// error checking in if conditionals. We can't merge this into > +// previous hunk, as this conflicts with other substitutions in it (at > +// least with "- local_err = NULL"). > +@ disable optional_qualifier@ > +identifier rule1.fn, rule1.local_err; > +symbol errp; > +@@ > + > + fn(..., Error ** ____, ...) > + { > + <... > +- local_err > ++ *errp > + ...> > + } > + > +// Always use the same pattern for checking error > +@ disable optional_qualifier@ > +identifier rule1.fn; > +symbol errp; > +@@ > + > + fn(..., Error ** ____, ...) > + { > + <... > +- *errp != NULL > ++ *errp > + ...> > + } > + > +// Revert temporary ___ identifier. > +@ disable optional_qualifier@ > +identifier rule1.fn; > +@@ > + > + fn(..., Error ** > +- ____ > ++ errp > + , ...) > + { > + ... > + } > diff --git a/include/qapi/error.h b/include/qapi/error.h > index 30140d9bfe..56c133520d 100644 > --- a/include/qapi/error.h > +++ b/include/qapi/error.h > @@ -214,6 +214,9 @@ > * } > * ... > * } > + * > + * For mass-conversion use script > + * scripts/coccinelle/auto-propagated-errp.cocci > */ > > #ifndef ERROR_H > diff --git a/MAINTAINERS b/MAINTAINERS > index 32867bc636..8b77127c35 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -2016,6 +2016,7 @@ F: include/qemu/error-report.h > F: qapi/error.json > F: util/error.c > F: util/qemu-error.c > +F: scripts/coccinelle/*err*.cocci > > GDB stub > M: Alex Bennée <alex.bennee@linaro.org> With the minor comment issues addressed: Reviewed-by: Markus Armbruster <armbru@redhat.com>
diff --git a/scripts/coccinelle/auto-propagated-errp.cocci b/scripts/coccinelle/auto-propagated-errp.cocci new file mode 100644 index 0000000000..5188b07006 --- /dev/null +++ b/scripts/coccinelle/auto-propagated-errp.cocci @@ -0,0 +1,336 @@ +// Use ERRP_AUTO_PROPAGATE (see include/qapi/error.h) +// +// Copyright (c) 2020 Virtuozzo International GmbH. +// +// This program is free software; you can redistribute it and/or +// modify it under the terms of the GNU General Public License as +// published by the Free Software Foundation; either version 2 of the +// License, or (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see +// <http://www.gnu.org/licenses/>. +// +// Usage example: +// spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \ +// --macro-file scripts/cocci-macro-file.h --in-place \ +// --no-show-diff --max-width 80 FILES... +// +// Note: --max-width 80 is needed because coccinelle default is less +// than 80, and without this parameter coccinelle may reindent some +// lines which fit into 80 characters but not to coccinelle default, +// which in turn produces extra patch hunks for no reason. + +// Switch unusual Error ** parameter names to errp +// (this is necessary to use ERRP_AUTO_PROPAGATE). +// +// Disable optional_qualifier to skip functions with +// "Error *const *errp" parameter. +// +// Skip functions with "assert(_errp && *_errp)" statement, because +// that signals unusual semantics, and the parameter name may well +// serve a purpose. (like nbd_iter_channel_error()). +// +// Skip util/error.c to not touch, for example, error_propagate() and +// error_propagate_prepend(). +@ depends on !(file in "util/error.c") disable optional_qualifier@ +identifier fn; +identifier _errp != errp; +@@ + + fn(..., +- Error **_errp ++ Error **errp + ,...) + { +( + ... when != assert(_errp && *_errp) +& + <... +- _errp ++ errp + ...> +) + } + +// Add invocation of ERRP_AUTO_PROPAGATE to errp-functions where +// necessary +// +// Note, that without "when any" the final "..." does not mach +// something matched by previous pattern, i.e. the rule will not match +// double error_prepend in control flow like in +// vfio_set_irq_signaling(). +// +// Note, "exists" says that we want apply rule even if it does not +// match on all possible control flows (otherwise, it will not match +// standard pattern when error_propagate() call is in if branch). +@ disable optional_qualifier exists@ +identifier fn, local_err; +symbol errp; +@@ + + fn(..., Error **errp, ...) + { ++ ERRP_AUTO_PROPAGATE(); + ... when != ERRP_AUTO_PROPAGATE(); +( +( + error_append_hint(errp, ...); +| + error_prepend(errp, ...); +| + error_vprepend(errp, ...); +) + ... when any +| + Error *local_err = NULL; + ... +( + error_propagate_prepend(errp, local_err, ...); +| + error_propagate(errp, local_err); +) + ... +) + } + +// Warn when several Error * definitions are in the control flow. +// This rule is not chained to rule1 and less restrictive, to cover more +// functions to warn (even those we are not going to convert). +// +// Note, that even with one (or zero) Error * definition in the each +// control flow we may have several (in total) Error * definitions in +// the function. This case deserves attention too, but I don't see +// simple way to match with help of coccinelle. +@check1 disable optional_qualifier exists@ +identifier fn, _errp, local_err, local_err2; +position p1, p2; +@@ + + fn(..., Error **_errp, ...) + { + ... + Error *local_err = NULL;@p1 + ... when any + Error *local_err2 = NULL;@p2 + ... when any + } + +@ script:python @ +fn << check1.fn; +p1 << check1.p1; +p2 << check1.p2; +@@ + +print('Warning: function {} has several definitions of ' + 'Error * local variable: at {}:{} and then at {}:{}'.format( + fn, p1[0].file, p1[0].line, p2[0].file, p2[0].line)) + +// Warn when several propagations are in the control flow. +@check2 disable optional_qualifier exists@ +identifier fn, _errp; +position p1, p2; +@@ + + fn(..., Error **_errp, ...) + { + ... +( + error_propagate_prepend(_errp, ...);@p1 +| + error_propagate(_errp, ...);@p1 +) + ... +( + error_propagate_prepend(_errp, ...);@p2 +| + error_propagate(_errp, ...);@p2 +) + ... when any + } + +@ script:python @ +fn << check2.fn; +p1 << check2.p1; +p2 << check2.p2; +@@ + +print('Warning: function {} propagates to errp several times in ' + 'one control flow: at {}:{} and then at {}:{}'.format( + fn, p1[0].file, p1[0].line, p2[0].file, p2[0].line)) + +// Match functions with propagation of local error to errp. +// We want to refer these functions in several following rules, but I +// don't know a proper way to inherit a function, not just its name +// (to not match another functions with same name in following rules). +// Not-proper way is as follows: rename errp parameter in functions +// header and match it in following rules. Rename it back after all +// transformations. +// +// The common case is a single definition of local_err with at most one +// error_propagate_prepend() or error_propagate() on each control-flow +// path. Functions with multiple definitions or propagates we want to +// examine manually. Later rules emit warnings to guide us to them. +// +// Note that we match not only this "common case", but any function, +// which has the "common cose" on at least one control-flow path. +@rule1 disable optional_qualifier exists@ +identifier fn, local_err; +symbol errp; +@@ + + fn(..., Error ** +- errp ++ ____ + , ...) + { + ... + Error *local_err = NULL; + ... +( + error_propagate_prepend(errp, local_err, ...); +| + error_propagate(errp, local_err); +) + ... + } + +// Convert special case with goto separately. +// I tried merging this into the following rule the obvious way, but +// it made Coccinelle hang on block.c +// +// Note interesting thing: if we don't do it here, and try to fixup +// "out: }" things later after all transformations (the rule will be +// the same, just without error_propagate() call), coccinelle fails to +// match this "out: }". +@ disable optional_qualifier@ +identifier rule1.fn, rule1.local_err, out; +symbol errp; +@@ + + fn(..., Error ** ____, ...) + { + <... +- goto out; ++ return; + ...> +- out: +- error_propagate(errp, local_err); + } + +// Convert most of local_err related stuff. +// +// Note, that we inherit rule1.fn and rule1.local_err names, not +// objects themselves. We may match something not related to the +// pattern matched by rule1. For example, local_err may be defined with +// the same name in different blocks inside one function, and in one +// block follow the propagation pattern and in other block doesn't. +// +// Note also that errp-cleaning functions +// error_free_errp +// error_report_errp +// error_reportf_errp +// warn_report_errp +// warn_reportf_errp +// are not yet implemented. They must call corresponding Error* - +// freeing function and then set *errp to NULL, to avoid further +// propagation to original errp (consider ERRP_AUTO_PROPAGATE in use). +// For example, error_free_errp may look like this: +// +// void error_free_errp(Error **errp) +// { +// error_free(*errp); +// *errp = NULL; +// } +@ disable optional_qualifier exists@ +identifier rule1.fn, rule1.local_err; +expression list args; +symbol errp; +@@ + + fn(..., Error ** ____, ...) + { + <... +( +- Error *local_err = NULL; +| + +// Convert error clearing functions +( +- error_free(local_err); ++ error_free_errp(errp); +| +- error_report_err(local_err); ++ error_report_errp(errp); +| +- error_reportf_err(local_err, args); ++ error_reportf_errp(errp, args); +| +- warn_report_err(local_err); ++ warn_report_errp(errp); +| +- warn_reportf_err(local_err, args); ++ warn_reportf_errp(errp, args); +) +?- local_err = NULL; + +| +- error_propagate_prepend(errp, local_err, args); ++ error_prepend(errp, args); +| +- error_propagate(errp, local_err); +| +- &local_err ++ errp +) + ...> + } + +// Convert remaining local_err usage. For example, different kinds of +// error checking in if conditionals. We can't merge this into +// previous hunk, as this conflicts with other substitutions in it (at +// least with "- local_err = NULL"). +@ disable optional_qualifier@ +identifier rule1.fn, rule1.local_err; +symbol errp; +@@ + + fn(..., Error ** ____, ...) + { + <... +- local_err ++ *errp + ...> + } + +// Always use the same pattern for checking error +@ disable optional_qualifier@ +identifier rule1.fn; +symbol errp; +@@ + + fn(..., Error ** ____, ...) + { + <... +- *errp != NULL ++ *errp + ...> + } + +// Revert temporary ___ identifier. +@ disable optional_qualifier@ +identifier rule1.fn; +@@ + + fn(..., Error ** +- ____ ++ errp + , ...) + { + ... + } diff --git a/include/qapi/error.h b/include/qapi/error.h index 30140d9bfe..56c133520d 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -214,6 +214,9 @@ * } * ... * } + * + * For mass-conversion use script + * scripts/coccinelle/auto-propagated-errp.cocci */ #ifndef ERROR_H diff --git a/MAINTAINERS b/MAINTAINERS index 32867bc636..8b77127c35 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2016,6 +2016,7 @@ F: include/qemu/error-report.h F: qapi/error.json F: util/error.c F: util/qemu-error.c +F: scripts/coccinelle/*err*.cocci GDB stub M: Alex Bennée <alex.bennee@linaro.org>
Script adds ERRP_AUTO_PROPAGATE macro invocation where appropriate and does corresponding changes in code (look for details in include/qapi/error.h) Usage example: spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \ --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff \ --max-width 80 FILES... Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- Cc: Eric Blake <eblake@redhat.com> Cc: Kevin Wolf <kwolf@redhat.com> Cc: Max Reitz <mreitz@redhat.com> Cc: Greg Kurz <groug@kaod.org> Cc: Christian Schoenebeck <qemu_oss@crudebyte.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Paul Durrant <paul@xen.org> Cc: "Philippe Mathieu-Daudé" <philmd@redhat.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Stefan Berger <stefanb@linux.ibm.com> Cc: Markus Armbruster <armbru@redhat.com> Cc: Michael Roth <mdroth@linux.vnet.ibm.com> Cc: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org Cc: xen-devel@lists.xenproject.org scripts/coccinelle/auto-propagated-errp.cocci | 336 ++++++++++++++++++ include/qapi/error.h | 3 + MAINTAINERS | 1 + 3 files changed, 340 insertions(+) create mode 100644 scripts/coccinelle/auto-propagated-errp.cocci