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      1 /*
      2  * Copyright (C) 2015 Cyril Hrubis <chrubis (at) suse.cz>
      3  *
      4  * This program is free software; you can redistribute it and/or modify it
      5  * under the terms of version 2 of the GNU General Public License as
      6  * published by the Free Software Foundation.
      7  *
      8  * This program is distributed in the hope that it would be useful, but
      9  * WITHOUT ANY WARRANTY; without even the implied warranty of
     10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
     11  *
     12  * Further, this software is distributed without any warranty that it is
     13  * free of the rightful claim of any third person regarding infringement
     14  * or the like.  Any license provided herein, whether implied or
     15  * otherwise, applies only to this software file.  Patent licenses, if
     16  * any, provided herein do not apply to combinations of this program with
     17  * other software, or any other product whatsoever.
     18  *
     19  * You should have received a copy of the GNU General Public License along
     20  * with this program; if not, write the Free Software Foundation, Inc.,
     21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
     22  */
     23 
     24 #include <stdint.h>
     25 #include <limits.h>
     26 #include <errno.h>
     27 #include <sys/syscall.h>
     28 #include <linux/futex.h>
     29 
     30 #include "test.h"
     31 #include "safe_macros.h"
     32 #include "lapi/futex.h"
     33 
     34 #define DEFAULT_MSEC_TIMEOUT 10000
     35 
     36 futex_t *tst_futexes;
     37 unsigned int tst_max_futexes;
     38 
     39 void tst_checkpoint_init(const char *file, const int lineno,
     40                          void (*cleanup_fn)(void))
     41 {
     42 	int fd;
     43 	unsigned int page_size;
     44 
     45 	if (tst_futexes) {
     46 		tst_brkm(TBROK, cleanup_fn,
     47 		         "%s: %d checkpoints already initialized",
     48 		         file, lineno);
     49 		return;
     50 	}
     51 
     52 	/*
     53 	 * The parent test process is responsible for creating the temporary
     54 	 * directory and therefore must pass non-zero cleanup (to remove the
     55 	 * directory if something went wrong).
     56 	 *
     57 	 * We cannot do this check unconditionally because if we need to init
     58 	 * the checkpoint from a binary that was started by exec() the
     59 	 * tst_tmpdir_created() will return false because the tmpdir was
     60 	 * created by parent. In this case we expect the subprogram can call
     61 	 * the init as a first function with NULL as cleanup function.
     62 	 */
     63 	if (cleanup_fn && !tst_tmpdir_created()) {
     64 		tst_brkm(TBROK, cleanup_fn,
     65 		         "%s:%d You have to create test temporary directory "
     66 		         "first (call tst_tmpdir())", file, lineno);
     67 		return;
     68 	}
     69 
     70 	page_size = getpagesize();
     71 
     72 	fd = SAFE_OPEN(cleanup_fn, "checkpoint_futex_base_file",
     73 	               O_RDWR | O_CREAT, 0666);
     74 
     75 	SAFE_FTRUNCATE(cleanup_fn, fd, page_size);
     76 
     77 	tst_futexes = SAFE_MMAP(cleanup_fn, NULL, page_size,
     78 	                    PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
     79 
     80 	tst_max_futexes = page_size / sizeof(uint32_t);
     81 
     82 	SAFE_CLOSE(cleanup_fn, fd);
     83 }
     84 
     85 int tst_checkpoint_wait(unsigned int id, unsigned int msec_timeout)
     86 {
     87 	struct timespec timeout;
     88 
     89 	if (id >= tst_max_futexes) {
     90 		errno = EOVERFLOW;
     91 		return -1;
     92 	}
     93 
     94 	timeout.tv_sec = msec_timeout/1000;
     95 	timeout.tv_nsec = (msec_timeout%1000) * 1000000;
     96 
     97 	return syscall(SYS_futex, &tst_futexes[id], FUTEX_WAIT,
     98 		       tst_futexes[id], &timeout);
     99 }
    100 
    101 int tst_checkpoint_wake(unsigned int id, unsigned int nr_wake,
    102                         unsigned int msec_timeout)
    103 {
    104 	unsigned int msecs = 0, waked = 0;
    105 
    106 	if (id >= tst_max_futexes) {
    107 		errno = EOVERFLOW;
    108 		return -1;
    109 	}
    110 
    111 	for (;;) {
    112 		waked += syscall(SYS_futex, &tst_futexes[id], FUTEX_WAKE,
    113 				 INT_MAX, NULL);
    114 
    115 		if (waked == nr_wake)
    116 			break;
    117 
    118 		usleep(1000);
    119 		msecs++;
    120 
    121 		if (msecs >= msec_timeout) {
    122 			errno = ETIMEDOUT;
    123 			return -1;
    124 		}
    125 	}
    126 
    127 	return 0;
    128 }
    129 
    130 void tst_safe_checkpoint_wait(const char *file, const int lineno,
    131                               void (*cleanup_fn)(void), unsigned int id,
    132 			      unsigned int msec_timeout)
    133 {
    134 	int ret;
    135 
    136 	if (!msec_timeout)
    137 		msec_timeout = DEFAULT_MSEC_TIMEOUT;
    138 
    139 	ret = tst_checkpoint_wait(id, msec_timeout);
    140 
    141 	if (ret) {
    142 		tst_brkm(TBROK | TERRNO, cleanup_fn,
    143 		         "%s:%d: tst_checkpoint_wait(%u, %i)",
    144 		         file, lineno, id, msec_timeout);
    145 	}
    146 }
    147 
    148 void tst_safe_checkpoint_wake(const char *file, const int lineno,
    149                               void (*cleanup_fn)(void), unsigned int id,
    150                               unsigned int nr_wake)
    151 {
    152 	int ret = tst_checkpoint_wake(id, nr_wake, DEFAULT_MSEC_TIMEOUT);
    153 
    154 	if (ret) {
    155 		tst_brkm(TBROK | TERRNO, cleanup_fn,
    156 		         "%s:%d: tst_checkpoint_wake(%u, %u, %i)",
    157 		         file, lineno, id, nr_wake, DEFAULT_MSEC_TIMEOUT);
    158 	}
    159 }
    160