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/* Event-Based Branch Facility API. Perf-thread data function init.
*
* Copyright IBM Corp. 2013
*
* The MIT License (MIT)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* Contributors:
* IBM Corporation, Adhemerval Zanella - Initial implementation.
*/
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <gnu/libc-version.h>
#include "config.h"
#include "ebb-priv.h"
#include "ebb-init.h"
/* Sets if GLIBC supports the EBB fields (handler and context) in the
* Thread Control Block. */
int __paf_ebb_use_tcb = 0;
#ifndef USE_EBB_TCB
static inline const char *
__paf_ebb_init_readnumber (const char *str, int *ret)
{
#define MAX_NUMBER_LEN 16
char number[MAX_NUMBER_LEN];
char *endptr;
int i;
memset (number, 0, MAX_NUMBER_LEN);
for (i=0; (i<MAX_NUMBER_LEN) && (str[i] != '\0'); ++i)
{
if (str[i] == '.')
{
i++;
break;
}
number[i] = str[i];
}
*ret = strtol (number, &endptr, 10);
if ((errno == ERANGE) || (*endptr != '\0'))
return NULL;
return &str[i];
}
#endif /* USE_EBB_TCB */
/* Check GLIBC version to see if interneal TCB header supports or
* not the EBB fields. */
void
attribute_hidden
attribute_constructor
__paf_ebb_init_usage (void)
{
const char *save_area = getenv ("LIBPAF_EBB_SAVE_AREA");
if (save_area)
{
if (strncasecmp (save_area, "tcb", sizeof ("tcb") - 1) == 0)
{
__paf_ebb_use_tcb = 1;
return;
}
else if (strncasecmp (save_area, "tls", sizeof ("tls") - 1) == 0)
{
__paf_ebb_use_tcb = 0;
return;
}
DEBUG ("failed to parse LIBPAF_EBB_SAVE_AREA environment variable");
}
#if defined(USE_EBB_TCB)
__paf_ebb_use_tcb = 1;
#elif defined(USE_EBB_TLS)
__paf_ebb_use_tcb = 0;
#else
const char *glibc_release;
int major;
int minor;
glibc_release = gnu_get_libc_version ();
glibc_release = __paf_ebb_init_readnumber (glibc_release, &major);
if (glibc_release == NULL)
{
DEBUG ("failed to parse GLIBC version");
return;
}
if (major >= 3)
__paf_ebb_use_tcb = 1;
else
{
glibc_release = __paf_ebb_init_readnumber (glibc_release, &minor);
if (minor >= 18)
__paf_ebb_use_tcb = 1;
}
#endif
}
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