diff options
Diffstat (limited to 'sys/ddb/db_capture.c')
| -rw-r--r-- | sys/ddb/db_capture.c | 58 |
1 files changed, 55 insertions, 3 deletions
diff --git a/sys/ddb/db_capture.c b/sys/ddb/db_capture.c index 4e6dd7c..bbc7925 100644 --- a/sys/ddb/db_capture.c +++ b/sys/ddb/db_capture.c @@ -57,11 +57,13 @@ static MALLOC_DEFINE(M_DB_CAPTURE, "db_capture", "DDB capture buffer"); #define DB_CAPTURE_DEFAULTBUFSIZE 48*1024 #define DB_CAPTURE_MAXBUFSIZE 512*1024 +#define DB_CAPTURE_FILENAME "ddb.txt" /* Captured DDB output. */ static char *db_capture_buf; static u_int db_capture_bufsize = DB_CAPTURE_DEFAULTBUFSIZE; static u_int db_capture_maxbufsize = DB_CAPTURE_MAXBUFSIZE; /* Read-only. */ static u_int db_capture_bufoff; /* Next location to write in buffer. */ +static u_int db_capture_bufpadding; /* Amount of zero padding. */ static int db_capture_inpager; /* Suspend capture in pager. */ static int db_capture_inprogress; /* DDB capture currently in progress. */ @@ -79,6 +81,14 @@ SYSCTL_UINT(_debug_ddb_capture, OID_AUTO, maxbufsize, CTLFLAG_RD, "Maximum value for debug.ddb.capture.bufsize"); /* + * Various compile-time assertions: defaults must be even multiples of + * textdump block size. We also perform run-time checking of + * user-configurable values. + */ +CTASSERT(DB_CAPTURE_DEFAULTBUFSIZE % TEXTDUMP_BLOCKSIZE == 0); +CTASSERT(DB_CAPTURE_MAXBUFSIZE % TEXTDUMP_BLOCKSIZE == 0); + +/* * Boot-time allocation of the DDB capture buffer, if any. */ static void @@ -86,9 +96,9 @@ db_capture_sysinit(__unused void *dummy) { TUNABLE_INT_FETCH("debug.ddb.capture.bufsize", &db_capture_bufsize); + db_capture_bufsize = roundup(db_capture_bufsize, TEXTDUMP_BLOCKSIZE); if (db_capture_bufsize > DB_CAPTURE_MAXBUFSIZE) db_capture_bufsize = DB_CAPTURE_MAXBUFSIZE; - if (db_capture_bufsize != 0) db_capture_buf = malloc(db_capture_bufsize, M_DB_CAPTURE, M_WAITOK); @@ -110,9 +120,9 @@ sysctl_debug_ddb_capture_bufsize(SYSCTL_HANDLER_ARGS) error = sysctl_handle_int(oidp, &size, 0, req); if (error || req->newptr == NULL) return (error); + size = roundup(size, TEXTDUMP_BLOCKSIZE); if (size > DB_CAPTURE_MAXBUFSIZE) return (EINVAL); - sx_xlock(&db_capture_sx); if (size != 0) { /* @@ -216,6 +226,23 @@ db_capture_exitpager(void) } /* + * Zero out any bytes left in the last block of the DDB capture buffer. This + * is run shortly before writing the blocks to disk, rather than when output + * capture is stopped, in order to avoid injecting nul's into the middle of + * output. + */ +static void +db_capture_zeropad(void) +{ + u_int len; + + len = min(TEXTDUMP_BLOCKSIZE, (db_capture_bufsize - + db_capture_bufoff) % TEXTDUMP_BLOCKSIZE); + bzero(db_capture_buf + db_capture_bufoff, len); + db_capture_bufpadding = len; +} + +/* * Reset capture state, which flushes buffers. */ static void @@ -224,6 +251,7 @@ db_capture_reset(void) db_capture_inprogress = 0; db_capture_bufoff = 0; + db_capture_bufpadding = 0; } /* @@ -242,7 +270,9 @@ db_capture_start(void) } /* - * Terminate DDB output capture. + * Terminate DDB output capture--real work is deferred to db_capture_dump, + * which executes outside of the DDB context. We don't zero pad here because + * capture may be started again before the dump takes place. */ static void db_capture_stop(void) @@ -255,6 +285,28 @@ db_capture_stop(void) db_capture_inprogress = 0; } +/* + * Dump DDB(4) captured output (and resets capture buffers). + */ +void +db_capture_dump(struct dumperinfo *di) +{ + u_int offset; + + if (db_capture_bufoff == 0) + return; + + db_capture_zeropad(); + textdump_mkustar(textdump_block_buffer, DB_CAPTURE_FILENAME, + db_capture_bufoff); + (void)textdump_writenextblock(di, textdump_block_buffer); + for (offset = 0; offset < db_capture_bufoff + db_capture_bufpadding; + offset += TEXTDUMP_BLOCKSIZE) + (void)textdump_writenextblock(di, db_capture_buf + offset); + db_capture_bufoff = 0; + db_capture_bufpadding = 0; +} + /*- * DDB(4) command to manage capture: * |
