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/* -*- linux-c -*-
* Print Functions
* Copyright (C) 2007 Red Hat Inc.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#ifndef _PRINT_C_
#define _PRINT_C_
#include "string.h"
#include "vsprintf.c"
#include "transport/transport.c"
/** @file print.c
* Printing Functions.
*/
/** @addtogroup print Print Functions
* The print buffer is for collecting output to send to the user daemon.
* This is a per-cpu static buffer. The buffer is sent when
* _stp_print_flush() is called.
*
* The reason to do this is to allow multiple small prints to be combined then
* timestamped and sent together to staprun. This is more efficient than sending
* numerous small packets.
*
* This function is called automatically when the print buffer is full.
* It MUST also be called at the end of every probe that prints something.
* @{
*/
typedef struct __stp_pbuf {
uint32_t len; /* bytes used in the buffer */
char buf[STP_BUFFER_SIZE];
} _stp_pbuf;
void *Stp_pbuf = NULL;
/** private buffer for _stp_log() */
#define STP_LOG_BUF_LEN 256
typedef char _stp_lbuf[STP_LOG_BUF_LEN];
void *Stp_lbuf = NULL;
/* create percpu print and io buffers */
int _stp_print_init (void)
{
Stp_pbuf = alloc_percpu(_stp_pbuf);
if (unlikely(Stp_pbuf == 0))
return -1;
/* now initialize IO buffer used in io.c */
Stp_lbuf = alloc_percpu(_stp_lbuf);
if (unlikely(Stp_lbuf == 0)) {
free_percpu(Stp_pbuf);
return -1;
}
_stp_allocated_memory += (sizeof(_stp_pbuf)+sizeof(_stp_lbuf)) * num_online_cpus();
return 0;
}
void _stp_print_cleanup (void)
{
if (Stp_pbuf)
free_percpu(Stp_pbuf);
if (Stp_lbuf)
free_percpu(Stp_lbuf);
}
/* The relayfs API changed between 2.6.15 and 2.6.16. */
/* Use the appropriate print flush function. */
#ifdef STP_OLD_TRANSPORT
#include "print_old.c"
#else
#include "print_new.c"
#endif
#ifndef STP_MAXBINARYARGS
#define STP_MAXBINARYARGS 127
#endif
/** Reserves space in the output buffer for direct I/O.
*/
static void * _stp_reserve_bytes (int numbytes)
{
_stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
int size = STP_BUFFER_SIZE - pb->len;
void * ret;
if (unlikely(numbytes == 0 || numbytes > STP_BUFFER_SIZE))
return NULL;
if (unlikely(numbytes > size))
_stp_print_flush();
ret = pb->buf + pb->len;
pb->len += numbytes;
return ret;
}
/** Write 64-bit args directly into the output stream.
* This function takes a variable number of 64-bit arguments
* and writes them directly into the output stream. Marginally faster
* than doing the same in _stp_vsnprintf().
* @sa _stp_vsnprintf()
*/
static void _stp_print_binary (int num, ...)
{
va_list vargs;
int i;
int64_t *args;
if (unlikely(num > STP_MAXBINARYARGS))
num = STP_MAXBINARYARGS;
args = _stp_reserve_bytes(num * sizeof(int64_t));
if (likely(args != NULL)) {
va_start(vargs, num);
for (i = 0; i < num; i++) {
args[i] = va_arg(vargs, int64_t);
}
va_end(vargs);
}
}
/** Print into the print buffer.
* Like C printf.
*
* @sa _stp_print_flush()
*/
void _stp_printf (const char *fmt, ...)
{
int num;
va_list args;
_stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
char *buf = pb->buf + pb->len;
int size = STP_BUFFER_SIZE - pb->len;
va_start(args, fmt);
num = _stp_vsnprintf(buf, size, fmt, args);
va_end(args);
if (unlikely(num >= size)) {
/* overflowed the buffer */
if (pb->len == 0) {
/* A single print request exceeded the buffer size. */
/* Should not be possible with Systemtap-generated code. */
pb->len = STP_BUFFER_SIZE;
_stp_print_flush();
num = 0;
} else {
/* Need more space. Flush the previous contents */
_stp_print_flush();
/* try again */
va_start(args, fmt);
num = _stp_vsnprintf(pb->buf, STP_BUFFER_SIZE, fmt, args);
va_end(args);
}
}
pb->len += num;
}
/** Write a string into the print buffer.
* @param str A C string (char *)
*/
void _stp_print (const char *str)
{
int num = strlen (str);
_stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
int size = STP_BUFFER_SIZE - pb->len;
if (unlikely(num >= size)) {
_stp_print_flush();
if (num > STP_BUFFER_SIZE)
num = STP_BUFFER_SIZE;
}
memcpy (pb->buf + pb->len, str, num);
pb->len += num;
}
void _stp_print_char (const char c)
{
char *buf;
_stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
int size = STP_BUFFER_SIZE - pb->len;
if (unlikely(1 >= size))
_stp_print_flush();
pb->buf[pb->len] = c;
pb->len ++;
}
/* This function is used when printing maps or stats. */
/* Probably belongs elsewhere, but is here for now. */
/* It takes a format specification like those used for */
/* printing maps and stats. It prints chars until it sees */
/* a special format char (beginning with '%'. Then it */
/* returns a pointer to that. */
static char *next_fmt(char *fmt, int *num)
{
char *f = fmt;
int in_fmt = 0;
*num = 0;
while (*f) {
if (in_fmt) {
if (*f == '%') {
_stp_print_char('%');
in_fmt = 0;
} else if (*f > '0' && *f <= '9') {
*num = *f - '0';
f++;
return f;
} else
return f;
} else if (*f == '%')
in_fmt = 1;
else
_stp_print_char(*f);
f++;
}
return f;
}
/** @} */
#endif /* _PRINT_C_ */
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