net/tipc/dbg.c

   1 /*
   2  * net/tipc/dbg.c: TIPC print buffer routines for debugging
   3  *
   4  * Copyright (c) 1996-2006, Ericsson AB
   5  * Copyright (c) 2005-2006, 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 static char print_string[TIPC_PB_MAX_STR];
  42 static DEFINE_SPINLOCK(print_lock);
  43
  44 static struct print_buf null_buf = { NULL, 0, NULL, NULL };
  45 struct print_buf *TIPC_NULL = &null_buf;
  46
  47 static struct print_buf cons_buf = { NULL, 0, NULL, NULL };
  48 struct print_buf *TIPC_CONS = &cons_buf;
  49
  50 static struct print_buf log_buf = { NULL, 0, NULL, NULL };
  51 struct print_buf *TIPC_LOG = &log_buf;
  52
  53
  54 #define FORMAT(PTR,LEN,FMT) \
  55 {\
  56        va_list args;\
  57        va_start(args, FMT);\
  58        LEN = vsprintf(PTR, FMT, args);\
  59        va_end(args);\
  60        *(PTR + LEN) = '\0';\
  61 }
  62
  63 /*
  64  * Locking policy when using print buffers.
  65  *
  66  * The following routines use 'print_lock' for protection:
  67  * 1) tipc_printf()  - to protect its print buffer(s) and 'print_string'
  68  * 2) TIPC_TEE()     - to protect its print buffer(s)
  69  * 3) tipc_dump()    - to protect its print buffer(s) and 'print_string'
  70  * 4) tipc_log_XXX() - to protect TIPC_LOG
  71  *
  72  * All routines of the form tipc_printbuf_XXX() rely on the caller to prevent
  73  * simultaneous use of the print buffer(s) being manipulated.
  74  */
  75
  76 /**
  77  * tipc_printbuf_init - initialize print buffer to empty
  78  * @pb: pointer to print buffer structure
  79  * @raw: pointer to character array used by print buffer
  80  * @size: size of character array
  81  *
  82  * Makes the print buffer a null device that discards anything written to it
  83  * if the character array is too small (or absent).
  84  */
  85
  86 void tipc_printbuf_init(struct print_buf *pb, char *raw, u32 size)
  87 {
  88         pb->buf = raw;
  89         pb->crs = raw;
  90         pb->size = size;
  91         pb->next = NULL;
  92
  93         if (size < TIPC_PB_MIN_SIZE) {
  94                 pb->buf = NULL;
  95         } else if (raw) {
  96                 pb->buf[0] = 0;
  97                 pb->buf[size-1] = ~0;
  98         }
  99 }
 100
 101 /**
 102  * tipc_printbuf_reset - reinitialize print buffer to empty state
 103  * @pb: pointer to print buffer structure
 104  */
 105
 106 void tipc_printbuf_reset(struct print_buf *pb)
 107 {
 108         tipc_printbuf_init(pb, pb->buf, pb->size);
 109 }
 110
 111 /**
 112  * tipc_printbuf_empty - test if print buffer is in empty state
 113  * @pb: pointer to print buffer structure
 114  *
 115  * Returns non-zero if print buffer is empty.
 116  */
 117
 118 int tipc_printbuf_empty(struct print_buf *pb)
 119 {
 120         return (!pb->buf || (pb->crs == pb->buf));
 121 }
 122
 123 /**
 124  * tipc_printbuf_validate - check for print buffer overflow
 125  * @pb: pointer to print buffer structure
 126  *
 127  * Verifies that a print buffer has captured all data written to it.
 128  * If data has been lost, linearize buffer and prepend an error message
 129  *
 130  * Returns length of print buffer data string (including trailing NUL)
 131  */
 132
 133 int tipc_printbuf_validate(struct print_buf *pb)
 134 {
 135         char *err = "\n\n*** PRINT BUFFER OVERFLOW ***\n\n";
 136         char *cp_buf;
 137         struct print_buf cb;
 138
 139         if (!pb->buf)
 140                 return 0;
 141
 142         if (pb->buf[pb->size - 1] == 0) {
 143                 cp_buf = kmalloc(pb->size, GFP_ATOMIC);
 144                 if (cp_buf != NULL){
 145                         tipc_printbuf_init(&cb, cp_buf, pb->size);
 146                         tipc_printbuf_move(&cb, pb);
 147                         tipc_printbuf_move(pb, &cb);
 148                         kfree(cp_buf);
 149                         memcpy(pb->buf, err, strlen(err));
 150                 } else {
 151                         tipc_printbuf_reset(pb);
 152                         tipc_printf(pb, err);
 153                 }
 154         }
 155         return (pb->crs - pb->buf + 1);
 156 }
 157
 158 /**
 159  * tipc_printbuf_move - move print buffer contents to another print buffer
 160  * @pb_to: pointer to destination print buffer structure
 161  * @pb_from: pointer to source print buffer structure
 162  *
 163  * Current contents of destination print buffer (if any) are discarded.
 164  * Source print buffer becomes empty if a successful move occurs.
 165  */
 166
 167 void tipc_printbuf_move(struct print_buf *pb_to, struct print_buf *pb_from)
 168 {
 169         int len;
 170
 171         /* Handle the cases where contents can't be moved */
 172
 173         if (!pb_to->buf)
 174                 return;
 175
 176         if (!pb_from->buf) {
 177                 tipc_printbuf_reset(pb_to);
 178                 return;
 179         }
 180
 181         if (pb_to->size < pb_from->size) {
 182                 tipc_printbuf_reset(pb_to);
 183                 tipc_printf(pb_to, "*** PRINT BUFFER MOVE ERROR ***");
 184                 return;
 185         }
 186
 187         /* Copy data from char after cursor to end (if used) */
 188
 189         len = pb_from->buf + pb_from->size - pb_from->crs - 2;
 190         if ((pb_from->buf[pb_from->size-1] == 0) && (len > 0)) {
 191                 strcpy(pb_to->buf, pb_from->crs + 1);
 192                 pb_to->crs = pb_to->buf + len;
 193         } else
 194                 pb_to->crs = pb_to->buf;
 195
 196         /* Copy data from start to cursor (always) */
 197
 198         len = pb_from->crs - pb_from->buf;
 199         strcpy(pb_to->crs, pb_from->buf);
 200         pb_to->crs += len;
 201
 202         tipc_printbuf_reset(pb_from);
 203 }
 204
 205 /**
 206  * tipc_printf - append formatted output to print buffer chain
 207  * @pb: pointer to chain of print buffers (may be NULL)
 208  * @fmt: formatted info to be printed
 209  */
 210
 211 void tipc_printf(struct print_buf *pb, const char *fmt, ...)
 212 {
 213         int chars_to_add;
 214         int chars_left;
 215         char save_char;
 216         struct print_buf *pb_next;
 217
 218         spin_lock_bh(&print_lock);
 219         FORMAT(print_string, chars_to_add, fmt);
 220         if (chars_to_add >= TIPC_PB_MAX_STR)
 221                 strcpy(print_string, "*** PRINT BUFFER STRING TOO LONG ***");
 222
 223         while (pb) {
 224                 if (pb == TIPC_CONS)
 225                         printk(print_string);
 226                 else if (pb->buf) {
 227                         chars_left = pb->buf + pb->size - pb->crs - 1;
 228                         if (chars_to_add <= chars_left) {
 229                                 strcpy(pb->crs, print_string);
 230                                 pb->crs += chars_to_add;
 231                         } else if (chars_to_add >= (pb->size - 1)) {
 232                                 strcpy(pb->buf, print_string + chars_to_add + 1
 233                                        - pb->size);
 234                                 pb->crs = pb->buf + pb->size - 1;
 235                         } else {
 236                                 strcpy(pb->buf, print_string + chars_left);
 237                                 save_char = print_string[chars_left];
 238                                 print_string[chars_left] = 0;
 239                                 strcpy(pb->crs, print_string);
 240                                 print_string[chars_left] = save_char;
 241                                 pb->crs = pb->buf + chars_to_add - chars_left;
 242                         }
 243                 }
 244                 pb_next = pb->next;
 245                 pb->next = NULL;
 246                 pb = pb_next;
 247         }
 248         spin_unlock_bh(&print_lock);
 249 }
 250
 251 /**
 252  * TIPC_TEE - perform next output operation on both print buffers
 253  * @b0: pointer to chain of print buffers (may be NULL)
 254  * @b1: pointer to print buffer to add to chain
 255  *
 256  * Returns pointer to print buffer chain.
 257  */
 258
 259 struct print_buf *TIPC_TEE(struct print_buf *b0, struct print_buf *b1)
 260 {
 261         struct print_buf *pb = b0;
 262
 263         if (!b0 || (b0 == b1))
 264                 return b1;
 265
 266         spin_lock_bh(&print_lock);
 267         while (pb->next) {
 268                 if ((pb->next == b1) || (pb->next == b0))
 269                         pb->next = pb->next->next;
 270                 else
 271                         pb = pb->next;
 272         }
 273         pb->next = b1;
 274         spin_unlock_bh(&print_lock);
 275         return b0;
 276 }
 277
 278 /**
 279  * print_to_console - write string of bytes to console in multiple chunks
 280  */
 281
 282 static void print_to_console(char *crs, int len)
 283 {
 284         int rest = len;
 285
 286         while (rest > 0) {
 287                 int sz = rest < TIPC_PB_MAX_STR ? rest : TIPC_PB_MAX_STR;
 288                 char c = crs[sz];
 289
 290                 crs[sz] = 0;
 291                 printk((const char *)crs);
 292                 crs[sz] = c;
 293                 rest -= sz;
 294                 crs += sz;
 295         }
 296 }
 297
 298 /**
 299  * printbuf_dump - write print buffer contents to console
 300  */
 301
 302 static void printbuf_dump(struct print_buf *pb)
 303 {
 304         int len;
 305
 306         if (!pb->buf) {
 307                 printk("*** PRINT BUFFER NOT ALLOCATED ***");
 308                 return;
 309         }
 310
 311         /* Dump print buffer from char after cursor to end (if used) */
 312
 313         len = pb->buf + pb->size - pb->crs - 2;
 314         if ((pb->buf[pb->size - 1] == 0) && (len > 0))
 315                 print_to_console(pb->crs + 1, len);
 316
 317         /* Dump print buffer from start to cursor (always) */
 318
 319         len = pb->crs - pb->buf;
 320         print_to_console(pb->buf, len);
 321 }
 322
 323 /**
 324  * tipc_dump - dump non-console print buffer(s) to console
 325  * @pb: pointer to chain of print buffers
 326  */
 327
 328 void tipc_dump(struct print_buf *pb, const char *fmt, ...)
 329 {
 330         struct print_buf *pb_next;
 331         int len;
 332
 333         spin_lock_bh(&print_lock);
 334         FORMAT(print_string, len, fmt);
 335         printk(print_string);
 336
 337         for (; pb; pb = pb->next) {
 338                 if (pb != TIPC_CONS) {
 339                         printk("\n---- Start of %s log dump ----\n\n",
 340                                (pb == TIPC_LOG) ? "global" : "local");
 341                         printbuf_dump(pb);
 342                         tipc_printbuf_reset(pb);
 343                         printk("\n---- End of dump ----\n");
 344                 }
 345                 pb_next = pb->next;
 346                 pb->next = NULL;
 347                 pb = pb_next;
 348         }
 349         spin_unlock_bh(&print_lock);
 350 }
 351
 352 /**
 353  * tipc_log_stop - free up TIPC log print buffer
 354  */
 355
 356 void tipc_log_stop(void)
 357 {
 358         spin_lock_bh(&print_lock);
 359         if (TIPC_LOG->buf) {
 360                 kfree(TIPC_LOG->buf);
 361                 TIPC_LOG->buf = NULL;
 362         }
 363         spin_unlock_bh(&print_lock);
 364 }
 365
 366 /**
 367  * tipc_log_reinit - (re)initialize TIPC log print buffer
 368  * @log_size: print buffer size to use
 369  */
 370
 371 void tipc_log_reinit(int log_size)
 372 {
 373         tipc_log_stop();
 374
 375         if (log_size) {
 376                 if (log_size < TIPC_PB_MIN_SIZE)
 377                         log_size = TIPC_PB_MIN_SIZE;
 378                 spin_lock_bh(&print_lock);
 379                 tipc_printbuf_init(TIPC_LOG, kmalloc(log_size, GFP_ATOMIC),
 380                                    log_size);
 381                 spin_unlock_bh(&print_lock);
 382         }
 383 }
 384
 385 /**
 386  * tipc_log_resize - reconfigure size of TIPC log buffer
 387  */
 388
 389 struct sk_buff *tipc_log_resize(const void *req_tlv_area, int req_tlv_space)
 390 {
 391         u32 value;
 392
 393         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
 394                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 395
 396         value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 397         if (value != delimit(value, 0, 32768))
 398                 return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 399                                                    " (log size must be 0-32768)");
 400         tipc_log_reinit(value);
 401         return tipc_cfg_reply_none();
 402 }
 403
 404 /**
 405  * tipc_log_dump - capture TIPC log buffer contents in configuration message
 406  */
 407
 408 struct sk_buff *tipc_log_dump(void)
 409 {
 410         struct sk_buff *reply;
 411
 412         spin_lock_bh(&print_lock);
 413         if (!TIPC_LOG->buf)
 414                 reply = tipc_cfg_reply_ultra_string("log not activated\n");
 415         else if (tipc_printbuf_empty(TIPC_LOG))
 416                 reply = tipc_cfg_reply_ultra_string("log is empty\n");
 417         else {
 418                 struct tlv_desc *rep_tlv;
 419                 struct print_buf pb;
 420                 int str_len;
 421
 422                 str_len = min(TIPC_LOG->size, 32768u);
 423                 reply = tipc_cfg_reply_alloc(TLV_SPACE(str_len));
 424                 if (reply) {
 425                         rep_tlv = (struct tlv_desc *)reply->data;
 426                         tipc_printbuf_init(&pb, TLV_DATA(rep_tlv), str_len);
 427                         tipc_printbuf_move(&pb, TIPC_LOG);
 428                         str_len = strlen(TLV_DATA(rep_tlv)) + 1;
 429                         skb_put(reply, TLV_SPACE(str_len));
 430                         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
 431                 }
 432         }
 433         spin_unlock_bh(&print_lock);
 434         return reply;
 435 }
 436