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Commit fb6daa75 authored by Daniel Thompson's avatar Daniel Thompson Committed by Jason Wessel
Browse files

kdb: Provide forward search at more prompt 



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: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
parent ab08e464

kernel/debug/kdb/kdb_io.c

+20 −2
Original line number Diff line number Diff line
@@ -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 */

kernel/debug/kdb/kdb_main.c

+4 −3
Original line number Diff line number Diff line
@@ -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';

kernel/debug/kdb/kdb_private.h

+2 −0
Original line number Diff line number Diff line
@@ -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[];