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