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/*
* Author: Colin King <colin.king@canonical.com>
*
* Copyright (C) 2012 Canonical, Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/klog.h>
#include <limits.h>
#define TEST_PASSED (0)
#define TEST_FAILED (1)
#define TEST_ERROR (2)
#define MMAP_LEN (8192)
/* read kernel log */
char *klog_read(void)
{
int len;
char *klog;
if ((len = klogctl(10, NULL, 0)) < 0)
return NULL;
if ((klog = calloc(1, len)) == NULL)
return NULL;
if (klogctl(3, klog, len) < 0) {
free(klog);
return NULL;
}
return klog;
}
/*
* https://bugs.launchpad.net/ubuntu/+bug/870326
* open(), mmap(), close() and write to mapping causes
* an error.
*/
int main(int argc, char **argv)
{
int fd;
int rc = TEST_PASSED;
unsigned int *ptr;
char buffer[MMAP_LEN];
char *klog_before;
char *klog_after, *klog_new_text;
size_t n, lastline_len = 0;
if (argc < 2) {
fprintf(stderr, "Usage: file\n");
exit(TEST_ERROR);
}
if ((fd = open(argv[1], O_CREAT | O_RDWR, S_IRUSR | S_IWUSR)) < 0) {
fprintf(stderr, "Cannot create %s : %s\n",
argv[1], strerror(errno));
exit(TEST_ERROR);
}
memset(buffer, 'X', sizeof(buffer));
if (write(fd, buffer, sizeof(buffer)) < 0) {
fprintf(stderr, "Failed to write to %s : %s\n",
argv[1], strerror(errno));
close(fd);
rc = TEST_ERROR;
goto tidy;
}
ptr = mmap(NULL, MMAP_LEN, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (ptr == MAP_FAILED) {
fprintf(stderr, "Cannot mmap file %s : %s\n",
argv[1], strerror(errno));
close(fd);
rc = TEST_ERROR;
goto tidy;
}
if (close(fd) < 0) {
fprintf(stderr, "Failed to close : %s\n", strerror(errno));
munmap(ptr, MMAP_LEN);
rc = TEST_ERROR;
goto tidy;
}
if ((klog_before = klog_read()) == NULL) {
fprintf(stderr, "Failed to read kernel log\n");
munmap(ptr, MMAP_LEN);
rc = TEST_ERROR;
goto tidy;
}
/* Seek back to start of last line */
if ((n = strlen(klog_before)) > 0) {
n--;
lastline_len++;
while (n > 0 && klog_before[n-1] != '\n') {
n--;
lastline_len++;
}
}
/* Modify pages, this caused bug LP#870326 */
memset(ptr, ' ', MMAP_LEN);
if (munmap(ptr, MMAP_LEN) < 0) {
fprintf(stderr, "munmap failed : %s\n", strerror(errno));
free(klog_before);
rc = TEST_ERROR;
goto tidy;
}
/*
* Get klog again, find previous klog last line
* and offset to end of this
*/
if ((klog_after = klog_read()) == NULL) {
fprintf(stderr, "Failed to read kernel log\n");
free(klog_before);
rc = TEST_ERROR;
goto tidy;
}
klog_new_text = strstr(klog_after, klog_before + n);
/* Any new kernel log lines contain the error message? */
if (klog_new_text &&
strstr(klog_new_text + lastline_len,
"Error attempting to write lower page"))
rc = TEST_FAILED;
free(klog_before);
free(klog_after);
tidy:
unlink(argv[1]);
exit(rc);
}
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