1 2 /* 3 * Copyright (c) 2004 Daniel McNeil <daniel (at) osdl.org> 4 * 2004 Open Source Development Lab 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 13 * the GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 18 * 19 * Module: .c 20 */ 21 22 /* 23 * Change History: 24 * 25 * 2/2004 Marty Ridgeway (mridge (at) us.ibm.com) Changes to adapt to LTP 26 * 27 */ 28 /* 29 * dio_append - append zeroed data to a file using O_DIRECT while 30 * a 2nd process is doing buffered reads and check if the buffer 31 * reads always see zero. 32 */ 33 #define _GNU_SOURCE 34 35 #include <stdlib.h> 36 #include <sys/types.h> 37 #include <signal.h> 38 #include <fcntl.h> 39 #include <stdio.h> 40 #include <unistd.h> 41 #include <memory.h> 42 #include <limits.h> 43 #define NUM_CHILDREN 8 44 45 char *check_zero(unsigned char *buf, int size) 46 { 47 unsigned char *p; 48 49 p = buf; 50 51 while (size > 0) { 52 if (*buf != 0) { 53 fprintf(stderr, 54 "non zero buffer at buf[%d] => 0x%02x,%02x,%02x,%02x\n", 55 buf - p, (unsigned int)buf[0], 56 size > 1 ? (unsigned int)buf[1] : 0, 57 size > 2 ? (unsigned int)buf[2] : 0, 58 size > 3 ? (unsigned int)buf[3] : 0); 59 fprintf(stderr, "buf %p, p %p\n", buf, p); 60 return buf; 61 } 62 buf++; 63 size--; 64 } 65 return 0; /* all zeros */ 66 } 67 68 int read_eof(char *filename) 69 { 70 int fd; 71 int i; 72 int r; 73 char buf[4096]; 74 75 while ((fd = open(filename, O_RDONLY)) < 0) { 76 sleep(1); /* wait for file to be created */ 77 } 78 79 for (i = 0; i < 1000000; i++) { 80 off_t offset; 81 char *bufoff; 82 83 offset = lseek(fd, SEEK_END, 0); 84 r = read(fd, buf, 4096); 85 if (r > 0) { 86 if ((bufoff = check_zero(buf, r))) { 87 fprintf(stderr, "non-zero read at offset %p\n", 88 offset + bufoff); 89 exit(1); 90 } 91 } 92 } 93 return 0; 94 } 95 96 void dio_append(char *filename) 97 { 98 int fd; 99 void *bufptr; 100 int i; 101 int w; 102 103 fd = open(filename, O_DIRECT | O_WRONLY | O_CREAT, 0666); 104 105 if (fd < 0) { 106 perror("cannot create file"); 107 return; 108 } 109 110 if (posix_memalign(&bufptr, 4096, 64 * 1024)) { 111 perror("cannot malloc aligned memory"); 112 return; 113 } 114 115 memset(bufptr, 0, 64 * 1024); 116 for (i = 0; i < 1000; i++) { 117 if ((w = write(fd, bufptr, 64 * 1024)) != 64 * 1024) { 118 fprintf(stderr, "write %d returned %d\n", i, w); 119 } 120 } 121 } 122 123 int main(int argc, char **argv) 124 { 125 char filename[PATH_MAX]; 126 int pid[NUM_CHILDREN]; 127 int num_children = 1; 128 int i; 129 130 snprintf(filename, sizeof(filename), "%s/aiodio/file", 131 getenv("TMP") ? getenv("TMP") : "/tmp"); 132 133 printf("Begin dio_append test...\n"); 134 135 for (i = 0; i < num_children; i++) { 136 if ((pid[i] = fork()) == 0) { 137 /* child */ 138 return read_eof(filename); 139 } else if (pid[i] < 0) { 140 /* error */ 141 perror("fork error"); 142 break; 143 } else { 144 /* Parent */ 145 continue; 146 } 147 } 148 149 /* 150 * Parent appends to end of file using direct i/o 151 */ 152 153 dio_append(filename); 154 155 for (i = 0; i < num_children; i++) { 156 kill(pid[i], SIGTERM); 157 } 158 return 0; 159 } 160
