| |
| /* |
| * Copyright (c) 2004 Daniel McNeil <daniel@osdl.org> |
| * 2004 Open Source Development Lab |
| * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| * Module: .c |
| */ |
| |
| /* |
| * Change History: |
| * |
| * 2/2004 Marty Ridgeway (mridge@us.ibm.com) Changes to adapt to LTP |
| * |
| */ |
| /* |
| * dio_append - append zeroed data to a file using O_DIRECT while |
| * a 2nd process is doing buffered reads and check if the buffer |
| * reads always see zero. |
| */ |
| #define _GNU_SOURCE |
| |
| #include <stdlib.h> |
| #include <sys/types.h> |
| #include <signal.h> |
| #include <fcntl.h> |
| #include <stdio.h> |
| #include <unistd.h> |
| #include <memory.h> |
| #include <limits.h> |
| #define NUM_CHILDREN 8 |
| |
| char *check_zero(unsigned char *buf, int size) |
| { |
| unsigned char *p; |
| |
| p = buf; |
| |
| while (size > 0) { |
| if (*buf != 0) { |
| fprintf(stderr, "non zero buffer at buf[%d] => 0x%02x,%02x,%02x,%02x\n", |
| buf - p, (unsigned int)buf[0], |
| size > 1 ? (unsigned int)buf[1] : 0, |
| size > 2 ? (unsigned int)buf[2] : 0, |
| size > 3 ? (unsigned int)buf[3] : 0); |
| fprintf(stderr, "buf %p, p %p\n", buf, p); |
| return buf; |
| } |
| buf++; |
| size--; |
| } |
| return 0; /* all zeros */ |
| } |
| |
| int read_eof(char *filename) |
| { |
| int fd; |
| int i; |
| int r; |
| char buf[4096]; |
| |
| while ((fd = open(filename, O_RDONLY)) < 0) { |
| sleep(1); /* wait for file to be created */ |
| } |
| |
| for (i = 0 ; i < 1000000; i++) { |
| off_t offset; |
| char *bufoff; |
| |
| offset = lseek(fd, SEEK_END, 0); |
| r = read(fd, buf, 4096); |
| if (r > 0) { |
| if ((bufoff = check_zero(buf, r))) { |
| fprintf(stderr, "non-zero read at offset %p\n", |
| offset + bufoff); |
| exit(1); |
| } |
| } |
| } |
| return 0; |
| } |
| |
| void dio_append(char *filename) |
| { |
| int fd; |
| void *bufptr; |
| int i; |
| int w; |
| |
| fd = open(filename, O_DIRECT|O_WRONLY|O_CREAT, 0666); |
| |
| if (fd < 0) { |
| perror("cannot create file"); |
| return; |
| } |
| |
| if (posix_memalign(&bufptr, 4096, 64*1024)) { |
| perror("cannot malloc aligned memory"); |
| return; |
| } |
| |
| memset(bufptr, 0, 64*1024); |
| for (i = 0; i < 1000; i++) { |
| if ((w = write(fd, bufptr, 64*1024)) != 64*1024) { |
| fprintf(stderr, "write %d returned %d\n", i, w); |
| } |
| } |
| } |
| |
| int main(int argc, char **argv) |
| { |
| char filename[PATH_MAX]; |
| int pid[NUM_CHILDREN]; |
| int num_children = 1; |
| int i; |
| |
| snprintf(filename, sizeof(filename), "%s/aiodio/file", |
| getenv("TMP") ? getenv("TMP") : "/tmp"); |
| |
| printf("Begin dio_append test...\n"); |
| |
| for (i = 0; i < num_children; i++) { |
| if ((pid[i] = fork()) == 0) { |
| /* child */ |
| return read_eof(filename); |
| } else if (pid[i] < 0) { |
| /* error */ |
| perror("fork error"); |
| break; |
| } else { |
| /* Parent */ |
| continue; |
| } |
| } |
| |
| /* |
| * Parent appends to end of file using direct i/o |
| */ |
| |
| dio_append(filename); |
| |
| for (i = 0; i < num_children; i++) { |
| kill(pid[i], SIGTERM); |
| } |
| return 0; |
| } |