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* [Bug c/99196] New: GCC analyzer doesn't know that error (code != 0, ...) exits the program
@ 2021-02-22 10:32 rjones at redhat dot com
2021-02-22 15:22 ` [Bug analyzer/99196] " msebor at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: rjones at redhat dot com @ 2021-02-22 10:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99196
Bug ID: 99196
Summary: GCC analyzer doesn't know that error (code != 0, ...)
exits the program
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: rjones at redhat dot com
Target Milestone: ---
https://github.com/libguestfs/libguestfs/blob/f19fd566f6387ce7e4d82409528c9dde374d25e0/daemon/tar.c#L108
tar.c: In function 'read_error_file':
tar.c:113:11: error: use of NULL 'str' where non-null expected [CWE-476]
[-Werror=analyzer-null-argument]
113 | len = strlen (str);
| ^~~~~~~~~~~~
'read_error_file': events 1-7
|
| 109 | if (str == NULL) {
| | ^
| | |
| | (1) following 'true' branch (when 'str' is NULL)...
| 110 | str = strdup ("(no error)");
| | ~~~ ~~~~~~~~~~~~~~~~~~~~~
| | | |
| | | (3) allocated here
| | (2) ...to here
| 111 | if (str == NULL)
| | ~
| | |
| | (4) assuming 'str' is NULL
| | (5) following 'true' branch (when 'str' is NULL)...
| 112 | error (EXIT_FAILURE, errno, "strdup"); /* XXX */
| | ~~~~~
| | |
| | (6) ...to here
| 113 | len = strlen (str);
| | ~~~~~~~~~~~~
| | |
| | (7) argument 1 ('str') NULL where non-null expected
|
In file included from ../gnulib/lib/string.h:41,
from tar.c:23:
/usr/include/string.h:391:15: note: argument 1 of 'strlen' must be non-null
391 | extern size_t strlen (const char *__s)
| ^~~~~~
cc1: all warnings being treated as errors
In the original code if str == NULL, error (EXIT_FAILURE, ...) is
called which exits the program. Therefore strlen (NULL) cannot
be called so the warning is bogus.
https://www.man7.org/linux/man-pages/man3/error.3.html
"If status has a nonzero value, then error() calls exit(3) to
terminate the program using the given value as the exit status."
gcc-11.0.0-0.19.fc35.x86_64
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/99196] GCC analyzer doesn't know that error (code != 0, ...) exits the program
2021-02-22 10:32 [Bug c/99196] New: GCC analyzer doesn't know that error (code != 0, ...) exits the program rjones at redhat dot com
@ 2021-02-22 15:22 ` msebor at gcc dot gnu.org
2021-02-22 16:53 ` dmalcolm at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: msebor at gcc dot gnu.org @ 2021-02-22 15:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99196
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |msebor at gcc dot gnu.org
Component|c |analyzer
Assignee|unassigned at gcc dot gnu.org |dmalcolm at gcc dot gnu.org
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Reassigning to analyzer.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/99196] GCC analyzer doesn't know that error (code != 0, ...) exits the program
2021-02-22 10:32 [Bug c/99196] New: GCC analyzer doesn't know that error (code != 0, ...) exits the program rjones at redhat dot com
2021-02-22 15:22 ` [Bug analyzer/99196] " msebor at gcc dot gnu.org
@ 2021-02-22 16:53 ` dmalcolm at gcc dot gnu.org
2021-02-22 17:18 ` rjones at redhat dot com
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2021-02-22 16:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99196
David Malcolm <dmalcolm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-02-22
Status|UNCONFIRMED |ASSIGNED
Ever confirmed|0 |1
--- Comment #2 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Thanks for filing this; confirmed. I'm working on a fix.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/99196] GCC analyzer doesn't know that error (code != 0, ...) exits the program
2021-02-22 10:32 [Bug c/99196] New: GCC analyzer doesn't know that error (code != 0, ...) exits the program rjones at redhat dot com
2021-02-22 15:22 ` [Bug analyzer/99196] " msebor at gcc dot gnu.org
2021-02-22 16:53 ` dmalcolm at gcc dot gnu.org
@ 2021-02-22 17:18 ` rjones at redhat dot com
2021-02-22 23:47 ` cvs-commit at gcc dot gnu.org
2021-02-22 23:48 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rjones at redhat dot com @ 2021-02-22 17:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99196
--- Comment #3 from Richard W.M. Jones <rjones at redhat dot com> ---
Note if errcode == 0 then error does NOT exit :-)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/99196] GCC analyzer doesn't know that error (code != 0, ...) exits the program
2021-02-22 10:32 [Bug c/99196] New: GCC analyzer doesn't know that error (code != 0, ...) exits the program rjones at redhat dot com
` (2 preceding siblings ...)
2021-02-22 17:18 ` rjones at redhat dot com
@ 2021-02-22 23:47 ` cvs-commit at gcc dot gnu.org
2021-02-22 23:48 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-02-22 23:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99196
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Malcolm <dmalcolm@gcc.gnu.org>:
https://gcc.gnu.org/g:5ee4ba031dd9fc60bf2494ca30f46c0acaa34805
commit r11-7333-g5ee4ba031dd9fc60bf2494ca30f46c0acaa34805
Author: David Malcolm <dmalcolm@redhat.com>
Date: Mon Feb 22 18:46:05 2021 -0500
analyzer: handle error/error_at_line [PR99196]
PR analyzer/99196 describes a false positive from -fanalyzer due to
the analyzer not "knowing" that calls to GNU libc's error(3) with a
nonzero status terminate the process and thus don't return.
This patch fixes the false positive by special-casing "error" and
"error_at_line".
gcc/analyzer/ChangeLog:
PR analyzer/99196
* engine.cc (exploded_node::on_stmt): Provide terminate_path
flag as a way for on_call_pre to terminate the current analysis
path.
* region-model-impl-calls.cc (call_details::num_args): New.
(region_model::impl_call_error): New.
* region-model.cc (region_model::on_call_pre): Add param
"out_terminate_path". Handle "error" and "error_at_line".
* region-model.h (call_details::num_args): New decl.
(region_model::on_call_pre): Add param "out_terminate_path".
(region_model::impl_call_error): New decl.
gcc/testsuite/ChangeLog:
PR analyzer/99196
* gcc.dg/analyzer/error-1.c: New test.
* gcc.dg/analyzer/error-2.c: New test.
* gcc.dg/analyzer/error-3.c: New test.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/99196] GCC analyzer doesn't know that error (code != 0, ...) exits the program
2021-02-22 10:32 [Bug c/99196] New: GCC analyzer doesn't know that error (code != 0, ...) exits the program rjones at redhat dot com
` (3 preceding siblings ...)
2021-02-22 23:47 ` cvs-commit at gcc dot gnu.org
@ 2021-02-22 23:48 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2021-02-22 23:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99196
David Malcolm <dmalcolm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #5 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Should be fixed by the above commit
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-02-22 10:32 [Bug c/99196] New: GCC analyzer doesn't know that error (code != 0, ...) exits the program rjones at redhat dot com
2021-02-22 15:22 ` [Bug analyzer/99196] " msebor at gcc dot gnu.org
2021-02-22 16:53 ` dmalcolm at gcc dot gnu.org
2021-02-22 17:18 ` rjones at redhat dot com
2021-02-22 23:47 ` cvs-commit at gcc dot gnu.org
2021-02-22 23:48 ` dmalcolm at gcc dot gnu.org
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