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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;
}
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