Straight away let me say I have gotten around this and can now build grep. But
it toook me 2 days.
The actual bug is that `CFLAGS=` causes configure to enable gcc warnings. I
would then get multiline warnings like the one at end of this report. Because of
-Werror, the build would then stop.
I had been running configure as `CFLAGS='-g3 -ggdb' ./configure --disable-nls`.
Eventually I tried plain `./configure` which built. Tests revealed simply
`CFLAGS=-g ./configure` provokes the warnings. Now I run `CFLAGS='-g3 -ggdb'
./configure --disable-gcc-warnings --disable-nls`.
To stop other folks running into this, configure.ac needs to be fixed to not
--enable-gcc-warnings of its own accord.
Cheers ... Duncan.
========================================
All the "error" lines flagged by gcc11.2 are false alarms. This is a list of
them:
> exclude.c:691:10: error: leak of FILE 'in' [CWE-775]
> [-Werror=analyzer-file-leak]
> fts.c:1497:25: error: use of NULL 'cp' where non-null expected [CWE-476]
> [-Werror=analyzer-null-argument]
> regex_internal.c:992:17: error: dereference of possibly-NULL
> 'next_nodes.elems' [CWE-690] [-Werror=analyzer-possible-null-dereference]
> regex_internal.c:992:17: error: dereference of possibly-NULL
> '*dests_node.elems' [CWE-690] [-Werror=analyzer-possible-null-dereference]
> regex_internal.c:992:17: error: dereference of possibly-NULL
> 'union_set.elems' [CWE-690] [-Werror=analyzer-possible-null-dereference]
> regex_internal.c:992:17: error: dereference of possibly-NULL '*set.elems'
> [CWE-690] [-Werror=analyzer-possible-null-dereference]
> regex_internal.c:992:17: error: dereference of possibly-NULL '*set.elems'
> [CWE-690] [-Werror=analyzer-possible-null-dereference]
> regex_internal.c:992:17: error: dereference of possibly-NULL
> 'new_nodes.elems' [CWE-690] [-Werror=analyzer-possible-null-dereference]
> regex_internal.c:1040:7: error: use of possibly-NULL 'next_nodes.elems' where
> non-null expected [CWE-690] [-Werror=analyzer-possible-null-argument]
> regex_internal.c:1040:7: error: use of possibly-NULL '*dest.elems' where
> non-null expected [CWE-690] [-Werror=analyzer-possible-null-argument]
These are all in gnulib. The following patch eliminates all of them, but don't
apply it. The patch is to highlight code constructs that gcc can't analyse
adequately.
Should I report these to the gcc team? They tend to like simple sources with no
headers and so on - I don't know if I can find the time to do that. But maybe I
could do 1 or 2. At least it's their own source (gnu's, not gcc's).
========================================
Here's an analysis of the first alleged error. add_exclude_file() is a short
function:
> int
> add_exclude_file (void (*add_func) (struct exclude *, char const *, int),
> struct exclude *ex, char const *file_name, int options,
> char line_end)
> {
> bool use_stdin = file_name[0] == '-' && !file_name[1];
> FILE *in;
> int rc = 0;
>
> if (use_stdin)
> in = stdin;
> else if (! (in = fopen (file_name, "re")))
> return -1;
>
> rc = add_exclude_fp (call_addfn, ex, in, options, line_end, &add_func);
>
> if (!use_stdin && fclose (in) != 0)
> rc = -1;
>
> return rc;
> }
If `use_stdin` is false then `in` becomes the fd of some file. But if
`use_stdin` is false, then `in` is rigorously closed. So there can be no file
leak.
> In function 'add_exclude_file':
> exclude.c:691:10: error: leak of FILE 'in' [CWE-775]
> [-Werror=analyzer-file-leak]
> 691 | return rc;
> | ^~
> 'add_exclude_file': events 1-8
> |
> | 673 | add_exclude_file (void (*add_func) (struct exclude *, char const
> *, int),
> | | ^~~~~~~~~~~~~~~~
> | | |
> | | (1) entry to 'add_exclude_file'
> |......
> | 681 | if (use_stdin)
> | | ~
> | | |
> | | (2) following 'false' branch (when 'use_stdin == 0')...
> | 682 | in = stdin;
> | 683 | else if (! (in = fopen (file_name, "re")))
> | | ~ ~~~~~~~~~~~~~~~~~~~~~~~
> | | | |
> | | | (3) ...to here
> | | | (4) opened here
> | | (5) assuming 'in' is non-NULL
> | | (6) following 'false' branch (when 'in' is non-NULL)...
> |......
> | 686 | rc = add_exclude_fp (call_addfn, ex, in, options, line_end,
> &add_func);
> | |
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> | | |
> | | (7) ...to here
> | | (8) calling 'add_exclude_fp' from 'add_exclude_file'
> |
> +--'add_exclude_fp': event 9
> |
> | 608 | add_exclude_fp (void (*add_func) (struct exclude *, char
> const *, int, void *),
> | | ^~~~~~~~~~~~~~
> | | |
> | | (9) entry to 'add_exclude_fp'
> |
> 'add_exclude_fp': events 10-16
> |
> | 622 | while ((c = getc (fp)) != EOF)
> | | ^
> | | |
> | | (10) following 'false' branch
> (when 'c == -1')...
> |......
> | 629 | if (ferror (fp))
> | | ~~~~~~~~~~~
> | | |
> | | (11) ...to here
> |......
> | 634 | lim = buf + buf_count + ! (buf_count == 0 ||
> buf[buf_count - 1] == line_end);
> | |
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> | | |
> | | (12) following 'false' branch
> (when 'buf_count == 0')...
> | | (13) ...to here
> |......
> | 640 | for (p = buf; p < lim; p++)
> | | ~~~~~~~
> | | |
> | | (16) following 'false' branch (when 'p
> >= lim')...
> | 641 | if (*p == line_end)
> | | ~
> | | |
> | | (14) following 'true' branch...
> | 642 | {
> | 643 | char *pattern_end = p;
> | | ~~~~~~~~~~~
> | | |
> | | (15) ...to here
> |
> 'add_exclude_fp': event 17
> |
> | 661 | errno = e;
> | | ^~~~~
> | | |
> | | (17) ...to here
> |
> <------+
> |
> 'add_exclude_file': events 18-21
> |
> | 686 | rc = add_exclude_fp (call_addfn, ex, in, options, line_end,
> &add_func);
> | |
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> | | |
> | | (18) returning to 'add_exclude_file' from 'add_exclude_fp'
> | 687 |
> | 688 | if (!use_stdin && fclose (in) != 0)
> | | ~
> | | |
> | | (19) following 'false' branch...
> |......
> | 691 | return rc;
> | | ~~
> | | |
> | | (20) ...to here
> | | (21) 'in' leaks here; was opened at (4)
> |
> 13:51:11$ gcc --version
> gcc (GCC) 11.2.0
Duncan Roe (1):
Silly patch to avoid some gcc 11.2 warnings
lib/exclude.c | 9 +++++++--
lib/fts.c | 2 +-
lib/regex_internal.c | 6 +++---
3 files changed, 11 insertions(+), 6 deletions(-)
--
2.33.1
