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kdb: Provide forward search at more prompt

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Currently kdb allows the output of comamnds to be filtered using the
| grep feature. This is useful but does not permit the output emitted
shortly after a string match to be examined without wading through the
entire unfiltered output of the command. Such a feature is particularly
useful to navigate function traces because these traces often have a
useful trigger string *before* the point of interest.

This patch reuses the existing filtering logic to introduce a simple
forward search to kdb that can be triggered from the more prompt.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
This commit is contained in:
Daniel Thompson 2014-09-11 10:37:10 +01:00 committed by Jason Wessel
parent ab08e464a2
commit fb6daa7520
3 changed files with 26 additions and 5 deletions
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22
kernel/debug/kdb/kdb_io.c
View file

@ -680,6 +680,12 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
size_avail = sizeof(kdb_buffer) - len;
goto kdb_print_out;
}
if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH)
/*
* This was a interactive search (using '/' at more
* prompt) and it has completed. Clear the flag.
*/
kdb_grepping_flag = 0;
/*
* at this point the string is a full line and
* should be printed, up to the null.
@ -798,11 +804,23 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
kdb_nextline = linecount - 1;
kdb_printf("\r");
suspend_grep = 1; /* for this recursion */
} else if (buf1[0] == '/' && !kdb_grepping_flag) {
kdb_printf("\r");
kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
kdbgetenv("SEARCHPROMPT") ?: "search> ");
*strchrnul(kdb_grep_string, '\n') = '\0';
kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
suspend_grep = 1; /* for this recursion */
} else if (buf1[0] && buf1[0] != '\n') {
/* user hit something other than enter */
suspend_grep = 1; /* for this recursion */
kdb_printf("\nOnly 'q' or 'Q' are processed at more "
"prompt, input ignored\n");
if (buf1[0] != '/')
kdb_printf(
"\nOnly 'q', 'Q' or '/' are processed at "
"more prompt, input ignored\n");
else
kdb_printf("\n'/' cannot be used during | "
"grep filtering, input ignored\n");
} else if (kdb_grepping_flag) {
/* user hit enter */
suspend_grep = 1; /* for this recursion */

7
kernel/debug/kdb/kdb_main.c
View file

@ -50,8 +50,7 @@
static int kdb_cmd_enabled = CONFIG_KDB_DEFAULT_ENABLE;
module_param_named(cmd_enable, kdb_cmd_enabled, int, 0600);
#define GREP_LEN 256
char kdb_grep_string[GREP_LEN];
char kdb_grep_string[KDB_GREP_STRLEN];
int kdb_grepping_flag;
EXPORT_SYMBOL(kdb_grepping_flag);
int kdb_grep_leading;
@ -870,7 +869,7 @@ static void parse_grep(const char *str)
len = strlen(cp);
if (!len)
return;
if (len >= GREP_LEN) {
if (len >= KDB_GREP_STRLEN) {
kdb_printf("search string too long\n");
return;
}
@ -1280,6 +1279,8 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
kdb_nextline = 1;
KDB_STATE_CLEAR(SUPPRESS);
kdb_grepping_flag = 0;
/* ensure the old search does not leak into '/' commands */
kdb_grep_string[0] = '\0';
cmdbuf = cmd_cur;
*cmdbuf = '\0';

2
kernel/debug/kdb/kdb_private.h
View file

@ -196,7 +196,9 @@ extern int kdb_main_loop(kdb_reason_t, kdb_reason_t,
/* Miscellaneous functions and data areas */
extern int kdb_grepping_flag;
#define KDB_GREPPING_FLAG_SEARCH 0x8000
extern char kdb_grep_string[];
#define KDB_GREP_STRLEN 256
extern int kdb_grep_leading;
extern int kdb_grep_trailing;
extern char *kdb_cmds[];