From fb6daa7520f9d17a97e84a3d5a947819e0313f28 Mon Sep 17 00:00:00 2001 From: Daniel Thompson Date: Thu, 11 Sep 2014 10:37:10 +0100 Subject: [PATCH] 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: Daniel Thompson Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_io.c | 22 ++++++++++++++++++++-- kernel/debug/kdb/kdb_main.c | 7 ++++--- kernel/debug/kdb/kdb_private.h | 2 ++ 3 files changed, 26 insertions(+), 5 deletions(-) diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index a550afb99ebe..ca13e6215537 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -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 @@ kdb_printit: 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 */ diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 420418360b81..4121345498e0 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -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'; diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index eaacd1693954..da93894db7ba 100644 --- a/kernel/debug/kdb/kdb_private.h +++ b/kernel/debug/kdb/kdb_private.h @@ -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[];