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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 };
+static 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_dump() and tipc_log_XXX() leverage 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_reset(struct print_buf *pb);
+static int tipc_printbuf_empty(struct print_buf *pb);
+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);
+}
+
+#ifdef CONFIG_TIPC_DEBUG
+
+/**
+ * print_to_console - write string of bytes to console in multiple chunks
+ */
+
+static void print_to_console(char *crs, int len)
+{
+ int rest = len;
+
+ while (rest > 0) {
+ int sz = rest < TIPC_PB_MAX_STR ? rest : TIPC_PB_MAX_STR;
+ char c = crs[sz];
+
+ crs[sz] = 0;
+ printk((const char *)crs);
+ crs[sz] = c;
+ rest -= sz;
+ crs += sz;
+ }
+}
+
+/**
+ * printbuf_dump - write print buffer contents to console
+ */
+
+static void printbuf_dump(struct print_buf *pb)
+{
+ int len;
+
+ if (!pb->buf) {
+ printk("*** PRINT BUFFER NOT ALLOCATED ***");
+ return;
+ }
+
+ /* Dump print buffer from char after cursor to end (if used) */
+
+ len = pb->buf + pb->size - pb->crs - 2;
+ if ((pb->buf[pb->size - 1] == 0) && (len > 0))
+ print_to_console(pb->crs + 1, len);
+
+ /* Dump print buffer from start to cursor (always) */
+
+ len = pb->crs - pb->buf;
+ print_to_console(pb->buf, len);
+}
+
+/**
+ * tipc_dump_dbg - dump (non-console) print buffer to console
+ * @pb: pointer to print buffer
+ */
+
+void tipc_dump_dbg(struct print_buf *pb, const char *fmt, ...)
+{
+ int len;
+
+ if (pb == TIPC_CONS)
+ return;
+
+ spin_lock_bh(&print_lock);
+
+ FORMAT(print_string, len, fmt);
+ printk(print_string);
+
+ printk("\n---- Start of %s log dump ----\n\n",
+ (pb == TIPC_LOG) ? "global" : "local");
+ printbuf_dump(pb);
+ tipc_printbuf_reset(pb);
+ printk("\n---- End of dump ----\n");
+
+ spin_unlock_bh(&print_lock);
+}
+
+#endif
+
+/**
+ * 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 != delimit(value, 0, 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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