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kern/misc: Allow selective disabling of debug facility names

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Sometimes you only know which debug logging facility names you want to
turn off, not necessarily all the ones you want enabled. This patch allows
the debug string to contain facility names in the $debug variable which are
prefixed with a "-" to disable debug log messages for that conditional. Say
you want all debug logging on except for btrfs and scripting, then do:
"set debug=all,-btrfs,-scripting"

Note, that only the last occurrence of the facility name with or without a
leading "-" is considered. So simply appending ",-facilityname" to the
$debug variable will disable that conditional. To illustrate, the command
"set debug=all,-btrfs,-scripting,btrfs" will enable btrfs.

Also, add documentation explaining this new behavior.

Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Glenn Washburn 2022-01-01 23:02:59 -06:00 committed by Daniel Kiper
parent 980cffdbb0
commit fcf2594ca1
2 changed files with 47 additions and 7 deletions
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13
docs/grub.texi
View File

@ -3388,9 +3388,16 @@ processed by commands @command{configfile} (@pxref{configfile}) or @command{norm
@subsection debug
This variable may be set to enable debugging output from various components
of GRUB. The value is a list of debug facility names separated by
whitespace or @samp{,}, or @samp{all} to enable all available debugging
output. The facility names are the first argument to grub_dprintf. Consult
of GRUB. The value is an ordered list of debug facility names separated by
whitespace or @samp{,}. If the special facility named @samp{all} is present
then debugging output of all facility names is enabled at the start of
processing the value of this variable. A facility's debug output can then be
disabled by prefixing its name with a @samp{-}. The last occurence facility
name with or without a leading @samp{-} takes precendent over any previous
occurence. This allows the easy enabling or disabling of facilities by
appending a @samp{,} and then the facility name with or without the leading
@samp{-}, which will preserve the state of the rest of the facilities.
The facility names are the first argument to grub_dprintf. Consult the
source for more details.

41
grub-core/kern/misc.c
View File

@ -162,16 +162,49 @@ __attribute__ ((alias("grub_printf")));
int
grub_debug_enabled (const char * condition)
{
const char *debug;
const char *debug, *found;
grub_size_t clen;
int ret = 0;
debug = grub_env_get ("debug");
if (!debug)
return 0;
if (grub_strword (debug, "all") || grub_strword (debug, condition))
return 1;
if (grub_strword (debug, "all"))
{
if (debug[3] == '\0')
return 1;
ret = 1;
}
return 0;
clen = grub_strlen (condition);
found = debug-1;
while(1)
{
found = grub_strstr (found+1, condition);
if (found == NULL)
break;
/* Found condition is not a whole word, so ignore it. */
if (*(found + clen) != '\0' && *(found + clen) != ','
&& !grub_isspace (*(found + clen)))
continue;
/*
* If found condition is at the start of debug or the start is on a word
* boundary, then enable debug. Else if found condition is prefixed with
* '-' and the start is on a word boundary, then disable debug. If none
* of these cases, ignore.
*/
if (found == debug || *(found - 1) == ',' || grub_isspace (*(found - 1)))
ret = 1;
else if (*(found - 1) == '-' && ((found == debug + 1) || (*(found - 2) == ','
|| grub_isspace (*(found - 2)))))
ret = 0;
}
return ret;
}
void