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![Allan Stephens](/assets/img/avatar_default.png)
Completes the simplification of TIPC's debugging capabilities. By default TIPC includes no debugging code, and any debugging code added by developers that calls the dbg() and dbg_macros() is compiled out. If debugging support is enabled, TIPC prints out some additional data about its internal state when certain abnormal conditions occur, and any developer-added calls to the TIPC debug macros are compiled in. Signed-off-by: Allan Stephens <Allan.Stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
351 lines
9.7 KiB
C
351 lines
9.7 KiB
C
/*
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* net/tipc/log.c: TIPC print buffer routines for debugging
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*
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* Copyright (c) 1996-2006, Ericsson AB
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* Copyright (c) 2005-2007, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "core.h"
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#include "config.h"
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#include "log.h"
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/*
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* TIPC pre-defines the following print buffers:
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*
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* TIPC_NULL : null buffer (i.e. print nowhere)
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* TIPC_CONS : system console
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* TIPC_LOG : TIPC log buffer
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*
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* Additional user-defined print buffers are also permitted.
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*/
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static struct print_buf null_buf = { NULL, 0, NULL, 0 };
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struct print_buf *const TIPC_NULL = &null_buf;
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static struct print_buf cons_buf = { NULL, 0, NULL, 1 };
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struct print_buf *const TIPC_CONS = &cons_buf;
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static struct print_buf log_buf = { NULL, 0, NULL, 1 };
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struct print_buf *const TIPC_LOG = &log_buf;
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/*
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* Locking policy when using print buffers.
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*
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* 1) tipc_printf() uses 'print_lock' to protect against concurrent access to
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* 'print_string' when writing to a print buffer. This also protects against
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* concurrent writes to the print buffer being written to.
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*
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* 2) tipc_log_XXX() leverages the aforementioned use of 'print_lock' to
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* protect against all types of concurrent operations on their associated
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* print buffer (not just write operations).
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*
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* Note: All routines of the form tipc_printbuf_XXX() are lock-free, and rely
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* on the caller to prevent simultaneous use of the print buffer(s) being
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* manipulated.
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*/
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static char print_string[TIPC_PB_MAX_STR];
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static DEFINE_SPINLOCK(print_lock);
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static void tipc_printbuf_move(struct print_buf *pb_to,
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struct print_buf *pb_from);
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#define FORMAT(PTR, LEN, FMT) \
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{\
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va_list args;\
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va_start(args, FMT);\
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LEN = vsprintf(PTR, FMT, args);\
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va_end(args);\
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*(PTR + LEN) = '\0';\
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}
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/**
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* tipc_printbuf_init - initialize print buffer to empty
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* @pb: pointer to print buffer structure
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* @raw: pointer to character array used by print buffer
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* @size: size of character array
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*
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* Note: If the character array is too small (or absent), the print buffer
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* becomes a null device that discards anything written to it.
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*/
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void tipc_printbuf_init(struct print_buf *pb, char *raw, u32 size)
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{
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pb->buf = raw;
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pb->crs = raw;
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pb->size = size;
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pb->echo = 0;
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if (size < TIPC_PB_MIN_SIZE) {
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pb->buf = NULL;
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} else if (raw) {
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pb->buf[0] = 0;
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pb->buf[size - 1] = ~0;
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}
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}
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/**
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* tipc_printbuf_reset - reinitialize print buffer to empty state
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* @pb: pointer to print buffer structure
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*/
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static void tipc_printbuf_reset(struct print_buf *pb)
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{
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if (pb->buf) {
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pb->crs = pb->buf;
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pb->buf[0] = 0;
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pb->buf[pb->size - 1] = ~0;
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}
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}
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/**
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* tipc_printbuf_empty - test if print buffer is in empty state
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* @pb: pointer to print buffer structure
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*
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* Returns non-zero if print buffer is empty.
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*/
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static int tipc_printbuf_empty(struct print_buf *pb)
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{
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return !pb->buf || (pb->crs == pb->buf);
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}
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/**
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* tipc_printbuf_validate - check for print buffer overflow
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* @pb: pointer to print buffer structure
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*
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* Verifies that a print buffer has captured all data written to it.
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* If data has been lost, linearize buffer and prepend an error message
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*
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* Returns length of print buffer data string (including trailing NUL)
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*/
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int tipc_printbuf_validate(struct print_buf *pb)
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{
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char *err = "\n\n*** PRINT BUFFER OVERFLOW ***\n\n";
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char *cp_buf;
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struct print_buf cb;
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if (!pb->buf)
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return 0;
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if (pb->buf[pb->size - 1] == 0) {
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cp_buf = kmalloc(pb->size, GFP_ATOMIC);
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if (cp_buf) {
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tipc_printbuf_init(&cb, cp_buf, pb->size);
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tipc_printbuf_move(&cb, pb);
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tipc_printbuf_move(pb, &cb);
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kfree(cp_buf);
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memcpy(pb->buf, err, strlen(err));
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} else {
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tipc_printbuf_reset(pb);
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tipc_printf(pb, err);
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}
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}
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return pb->crs - pb->buf + 1;
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}
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/**
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* tipc_printbuf_move - move print buffer contents to another print buffer
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* @pb_to: pointer to destination print buffer structure
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* @pb_from: pointer to source print buffer structure
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*
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* Current contents of destination print buffer (if any) are discarded.
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* Source print buffer becomes empty if a successful move occurs.
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*/
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static void tipc_printbuf_move(struct print_buf *pb_to,
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struct print_buf *pb_from)
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{
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int len;
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/* Handle the cases where contents can't be moved */
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if (!pb_to->buf)
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return;
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if (!pb_from->buf) {
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tipc_printbuf_reset(pb_to);
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return;
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}
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if (pb_to->size < pb_from->size) {
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strcpy(pb_to->buf, "*** PRINT BUFFER MOVE ERROR ***");
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pb_to->buf[pb_to->size - 1] = ~0;
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pb_to->crs = strchr(pb_to->buf, 0);
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return;
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}
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/* Copy data from char after cursor to end (if used) */
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len = pb_from->buf + pb_from->size - pb_from->crs - 2;
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if ((pb_from->buf[pb_from->size - 1] == 0) && (len > 0)) {
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strcpy(pb_to->buf, pb_from->crs + 1);
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pb_to->crs = pb_to->buf + len;
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} else
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pb_to->crs = pb_to->buf;
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/* Copy data from start to cursor (always) */
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len = pb_from->crs - pb_from->buf;
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strcpy(pb_to->crs, pb_from->buf);
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pb_to->crs += len;
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tipc_printbuf_reset(pb_from);
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}
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/**
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* tipc_printf - append formatted output to print buffer
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* @pb: pointer to print buffer
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* @fmt: formatted info to be printed
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*/
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void tipc_printf(struct print_buf *pb, const char *fmt, ...)
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{
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int chars_to_add;
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int chars_left;
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char save_char;
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spin_lock_bh(&print_lock);
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FORMAT(print_string, chars_to_add, fmt);
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if (chars_to_add >= TIPC_PB_MAX_STR)
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strcpy(print_string, "*** PRINT BUFFER STRING TOO LONG ***");
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if (pb->buf) {
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chars_left = pb->buf + pb->size - pb->crs - 1;
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if (chars_to_add <= chars_left) {
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strcpy(pb->crs, print_string);
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pb->crs += chars_to_add;
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} else if (chars_to_add >= (pb->size - 1)) {
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strcpy(pb->buf, print_string + chars_to_add + 1
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- pb->size);
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pb->crs = pb->buf + pb->size - 1;
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} else {
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strcpy(pb->buf, print_string + chars_left);
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save_char = print_string[chars_left];
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print_string[chars_left] = 0;
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strcpy(pb->crs, print_string);
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print_string[chars_left] = save_char;
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pb->crs = pb->buf + chars_to_add - chars_left;
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}
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}
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if (pb->echo)
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printk("%s", print_string);
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spin_unlock_bh(&print_lock);
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}
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/**
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* tipc_log_resize - change the size of the TIPC log buffer
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* @log_size: print buffer size to use
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*/
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int tipc_log_resize(int log_size)
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{
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int res = 0;
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spin_lock_bh(&print_lock);
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kfree(TIPC_LOG->buf);
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TIPC_LOG->buf = NULL;
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if (log_size) {
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if (log_size < TIPC_PB_MIN_SIZE)
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log_size = TIPC_PB_MIN_SIZE;
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res = TIPC_LOG->echo;
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tipc_printbuf_init(TIPC_LOG, kmalloc(log_size, GFP_ATOMIC),
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log_size);
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TIPC_LOG->echo = res;
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res = !TIPC_LOG->buf;
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}
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spin_unlock_bh(&print_lock);
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return res;
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}
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/**
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* tipc_log_resize_cmd - reconfigure size of TIPC log buffer
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*/
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struct sk_buff *tipc_log_resize_cmd(const void *req_tlv_area, int req_tlv_space)
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{
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u32 value;
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if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
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return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
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value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
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if (value != delimit(value, 0, 32768))
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return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
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" (log size must be 0-32768)");
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if (tipc_log_resize(value))
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return tipc_cfg_reply_error_string(
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"unable to create specified log (log size is now 0)");
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return tipc_cfg_reply_none();
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}
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/**
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* tipc_log_dump - capture TIPC log buffer contents in configuration message
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*/
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struct sk_buff *tipc_log_dump(void)
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{
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struct sk_buff *reply;
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spin_lock_bh(&print_lock);
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if (!TIPC_LOG->buf) {
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spin_unlock_bh(&print_lock);
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reply = tipc_cfg_reply_ultra_string("log not activated\n");
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} else if (tipc_printbuf_empty(TIPC_LOG)) {
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spin_unlock_bh(&print_lock);
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reply = tipc_cfg_reply_ultra_string("log is empty\n");
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} else {
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struct tlv_desc *rep_tlv;
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struct print_buf pb;
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int str_len;
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str_len = min(TIPC_LOG->size, 32768u);
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spin_unlock_bh(&print_lock);
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reply = tipc_cfg_reply_alloc(TLV_SPACE(str_len));
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if (reply) {
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rep_tlv = (struct tlv_desc *)reply->data;
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tipc_printbuf_init(&pb, TLV_DATA(rep_tlv), str_len);
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spin_lock_bh(&print_lock);
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tipc_printbuf_move(&pb, TIPC_LOG);
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spin_unlock_bh(&print_lock);
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str_len = strlen(TLV_DATA(rep_tlv)) + 1;
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skb_put(reply, TLV_SPACE(str_len));
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TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
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}
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}
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return reply;
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}
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