net/tipc/dbg.c

   1 /*
   2  * net/tipc/dbg.c: TIPC print buffer routines for debuggign
   3  *
   4  * Copyright (c) 1996-2006, Ericsson AB
   5  * Copyright (c) 2005, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "config.h"
  39 #include "dbg.h"
  40
  41 #define MAX_STRING 512
  42
  43 static char print_string[MAX_STRING];
  44 static spinlock_t print_lock = SPIN_LOCK_UNLOCKED;
  45
  46 static struct print_buf cons_buf = { NULL, 0, NULL, NULL };
  47 struct print_buf *TIPC_CONS = &cons_buf;
  48
  49 static struct print_buf log_buf = { NULL, 0, NULL, NULL };
  50 struct print_buf *TIPC_LOG = &log_buf;
  51
  52
  53 #define FORMAT(PTR,LEN,FMT) \
  54 {\
  55        va_list args;\
  56        va_start(args, FMT);\
  57        LEN = vsprintf(PTR, FMT, args);\
  58        va_end(args);\
  59        *(PTR + LEN) = '\0';\
  60 }
  61
  62 /*
  63  * Locking policy when using print buffers.
  64  *
  65  * 1) Routines of the form printbuf_XXX() rely on the caller to prevent
  66  *    simultaneous use of the print buffer(s) being manipulated.
  67  * 2) tipc_printf() uses 'print_lock' to prevent simultaneous use of
  68  *    'print_string' and to protect its print buffer(s).
  69  * 3) TIPC_TEE() uses 'print_lock' to protect its print buffer(s).
  70  * 4) Routines of the form log_XXX() uses 'print_lock' to protect TIPC_LOG.
  71  */
  72
  73 /**
  74  * tipc_printbuf_init - initialize print buffer to empty
  75  */
  76
  77 void tipc_printbuf_init(struct print_buf *pb, char *raw, u32 sz)
  78 {
  79         if (!pb || !raw || (sz < (MAX_STRING + 1)))
  80                 return;
  81
  82         pb->crs = pb->buf = raw;
  83         pb->size = sz;
  84         pb->next = 0;
  85         pb->buf[0] = 0;
  86         pb->buf[sz-1] = ~0;
  87 }
  88
  89 /**
  90  * tipc_printbuf_reset - reinitialize print buffer to empty state
  91  */
  92
  93 void tipc_printbuf_reset(struct print_buf *pb)
  94 {
  95         if (pb && pb->buf)
  96                 tipc_printbuf_init(pb, pb->buf, pb->size);
  97 }
  98
  99 /**
 100  * tipc_printbuf_empty - test if print buffer is in empty state
 101  */
 102
 103 int tipc_printbuf_empty(struct print_buf *pb)
 104 {
 105         return (!pb || !pb->buf || (pb->crs == pb->buf));
 106 }
 107
 108 /**
 109  * tipc_printbuf_validate - check for print buffer overflow
 110  *
 111  * Verifies that a print buffer has captured all data written to it.
 112  * If data has been lost, linearize buffer and prepend an error message
 113  *
 114  * Returns length of print buffer data string (including trailing NULL)
 115  */
 116
 117 int tipc_printbuf_validate(struct print_buf *pb)
 118 {
 119         char *err = "             *** PRINT BUFFER WRAPPED AROUND ***\n";
 120         char *cp_buf;
 121         struct print_buf cb;
 122
 123         if (!pb || !pb->buf)
 124                 return 0;
 125
 126         if (pb->buf[pb->size - 1] == '\0') {
 127                 cp_buf = kmalloc(pb->size, GFP_ATOMIC);
 128                 if (cp_buf != NULL){
 129                         tipc_printbuf_init(&cb, cp_buf, pb->size);
 130                         tipc_printbuf_move(&cb, pb);
 131                         tipc_printbuf_move(pb, &cb);
 132                         kfree(cp_buf);
 133                         memcpy(pb->buf, err, strlen(err));
 134                 } else {
 135                         tipc_printbuf_reset(pb);
 136                         tipc_printf(pb, err);
 137                 }
 138         }
 139         return (pb->crs - pb->buf + 1);
 140 }
 141
 142 /**
 143  * tipc_printbuf_move - move print buffer contents to another print buffer
 144  *
 145  * Current contents of destination print buffer (if any) are discarded.
 146  * Source print buffer becomes empty if a successful move occurs.
 147  */
 148
 149 void tipc_printbuf_move(struct print_buf *pb_to, struct print_buf *pb_from)
 150 {
 151         int len;
 152
 153         /* Handle the cases where contents can't be moved */
 154
 155         if (!pb_to || !pb_to->buf)
 156                 return;
 157
 158         if (!pb_from || !pb_from->buf) {
 159                 tipc_printbuf_reset(pb_to);
 160                 return;
 161         }
 162
 163         if (pb_to->size < pb_from->size) {
 164                 tipc_printbuf_reset(pb_to);
 165                 tipc_printf(pb_to, "*** PRINT BUFFER OVERFLOW ***");
 166                 return;
 167         }
 168
 169         /* Copy data from char after cursor to end (if used) */
 170         len = pb_from->buf + pb_from->size - pb_from->crs - 2;
 171         if ((pb_from->buf[pb_from->size-1] == 0) && (len > 0)) {
 172                 strcpy(pb_to->buf, pb_from->crs + 1);
 173                 pb_to->crs = pb_to->buf + len;
 174         } else
 175                 pb_to->crs = pb_to->buf;
 176
 177         /* Copy data from start to cursor (always) */
 178         len = pb_from->crs - pb_from->buf;
 179         strcpy(pb_to->crs, pb_from->buf);
 180         pb_to->crs += len;
 181
 182         tipc_printbuf_reset(pb_from);
 183 }
 184
 185 /**
 186  * tipc_printf - append formatted output to print buffer chain
 187  */
 188
 189 void tipc_printf(struct print_buf *pb, const char *fmt, ...)
 190 {
 191         int chars_to_add;
 192         int chars_left;
 193         char save_char;
 194         struct print_buf *pb_next;
 195
 196         spin_lock_bh(&print_lock);
 197         FORMAT(print_string, chars_to_add, fmt);
 198         if (chars_to_add >= MAX_STRING)
 199                 strcpy(print_string, "*** STRING TOO LONG ***");
 200
 201         while (pb) {
 202                 if (pb == TIPC_CONS)
 203                         printk(print_string);
 204                 else if (pb->buf) {
 205                         chars_left = pb->buf + pb->size - pb->crs - 1;
 206                         if (chars_to_add <= chars_left) {
 207                                 strcpy(pb->crs, print_string);
 208                                 pb->crs += chars_to_add;
 209                         } else {
 210                                 strcpy(pb->buf, print_string + chars_left);
 211                                 save_char = print_string[chars_left];
 212                                 print_string[chars_left] = 0;
 213                                 strcpy(pb->crs, print_string);
 214                                 print_string[chars_left] = save_char;
 215                                 pb->crs = pb->buf + chars_to_add - chars_left;
 216                         }
 217                 }
 218                 pb_next = pb->next;
 219                 pb->next = 0;
 220                 pb = pb_next;
 221         }
 222         spin_unlock_bh(&print_lock);
 223 }
 224
 225 /**
 226  * TIPC_TEE - perform next output operation on both print buffers
 227  */
 228
 229 struct print_buf *TIPC_TEE(struct print_buf *b0, struct print_buf *b1)
 230 {
 231         struct print_buf *pb = b0;
 232
 233         if (!b0 || (b0 == b1))
 234                 return b1;
 235         if (!b1)
 236                 return b0;
 237
 238         spin_lock_bh(&print_lock);
 239         while (pb->next) {
 240                 if ((pb->next == b1) || (pb->next == b0))
 241                         pb->next = pb->next->next;
 242                 else
 243                         pb = pb->next;
 244         }
 245         pb->next = b1;
 246         spin_unlock_bh(&print_lock);
 247         return b0;
 248 }
 249
 250 /**
 251  * print_to_console - write string of bytes to console in multiple chunks
 252  */
 253
 254 static void print_to_console(char *crs, int len)
 255 {
 256         int rest = len;
 257
 258         while (rest > 0) {
 259                 int sz = rest < MAX_STRING ? rest : MAX_STRING;
 260                 char c = crs[sz];
 261
 262                 crs[sz] = 0;
 263                 printk((const char *)crs);
 264                 crs[sz] = c;
 265                 rest -= sz;
 266                 crs += sz;
 267         }
 268 }
 269
 270 /**
 271  * printbuf_dump - write print buffer contents to console
 272  */
 273
 274 static void printbuf_dump(struct print_buf *pb)
 275 {
 276         int len;
 277
 278         /* Dump print buffer from char after cursor to end (if used) */
 279         len = pb->buf + pb->size - pb->crs - 2;
 280         if ((pb->buf[pb->size - 1] == 0) && (len > 0))
 281                 print_to_console(pb->crs + 1, len);
 282
 283         /* Dump print buffer from start to cursor (always) */
 284         len = pb->crs - pb->buf;
 285         print_to_console(pb->buf, len);
 286 }
 287
 288 /**
 289  * tipc_dump - dump non-console print buffer(s) to console
 290  */
 291
 292 void tipc_dump(struct print_buf *pb, const char *fmt, ...)
 293 {
 294         int len;
 295
 296         spin_lock_bh(&print_lock);
 297         FORMAT(TIPC_CONS->buf, len, fmt);
 298         printk(TIPC_CONS->buf);
 299
 300         for (; pb; pb = pb->next) {
 301                 if (pb == TIPC_CONS)
 302                         continue;
 303                 printk("\n---- Start of dump,%s log ----\n\n",
 304                        (pb == TIPC_LOG) ? "global" : "local");
 305                 printbuf_dump(pb);
 306                 tipc_printbuf_reset(pb);
 307                 printk("\n-------- End of dump --------\n");
 308         }
 309         spin_unlock_bh(&print_lock);
 310 }
 311
 312 /**
 313  * tipc_log_stop - free up TIPC log print buffer
 314  */
 315
 316 void tipc_log_stop(void)
 317 {
 318         spin_lock_bh(&print_lock);
 319         if (TIPC_LOG->buf) {
 320                 kfree(TIPC_LOG->buf);
 321                 TIPC_LOG->buf = NULL;
 322         }
 323         spin_unlock_bh(&print_lock);
 324 }
 325
 326 /**
 327  * tipc_log_reinit - set TIPC log print buffer to specified size
 328  */
 329
 330 void tipc_log_reinit(int log_size)
 331 {
 332         tipc_log_stop();
 333
 334         if (log_size) {
 335                 if (log_size <= MAX_STRING)
 336                         log_size = MAX_STRING + 1;
 337                 spin_lock_bh(&print_lock);
 338                 tipc_printbuf_init(TIPC_LOG, kmalloc(log_size, GFP_ATOMIC), log_size);
 339                 spin_unlock_bh(&print_lock);
 340         }
 341 }
 342
 343 /**
 344  * tipc_log_resize - reconfigure size of TIPC log buffer
 345  */
 346
 347 struct sk_buff *tipc_log_resize(const void *req_tlv_area, int req_tlv_space)
 348 {
 349         u32 value;
 350
 351         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
 352                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 353
 354         value = *(u32 *)TLV_DATA(req_tlv_area);
 355         value = ntohl(value);
 356         if (value != delimit(value, 0, 32768))
 357                 return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 358                                                    " (log size must be 0-32768)");
 359         tipc_log_reinit(value);
 360         return tipc_cfg_reply_none();
 361 }
 362
 363 /**
 364  * tipc_log_dump - capture TIPC log buffer contents in configuration message
 365  */
 366
 367 struct sk_buff *tipc_log_dump(void)
 368 {
 369         struct sk_buff *reply;
 370
 371         spin_lock_bh(&print_lock);
 372         if (!TIPC_LOG->buf)
 373                 reply = tipc_cfg_reply_ultra_string("log not activated\n");
 374         else if (tipc_printbuf_empty(TIPC_LOG))
 375                 reply = tipc_cfg_reply_ultra_string("log is empty\n");
 376         else {
 377                 struct tlv_desc *rep_tlv;
 378                 struct print_buf pb;
 379                 int str_len;
 380
 381                 str_len = min(TIPC_LOG->size, 32768u);
 382                 reply = tipc_cfg_reply_alloc(TLV_SPACE(str_len));
 383                 if (reply) {
 384                         rep_tlv = (struct tlv_desc *)reply->data;
 385                         tipc_printbuf_init(&pb, TLV_DATA(rep_tlv), str_len);
 386                         tipc_printbuf_move(&pb, TIPC_LOG);
 387                         str_len = strlen(TLV_DATA(rep_tlv)) + 1;
 388                         skb_put(reply, TLV_SPACE(str_len));
 389                         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
 390                 }
 391         }
 392         spin_unlock_bh(&print_lock);
 393         return reply;
 394 }
 395