1 | /*
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2 | * finddev.c -- this routine attempts to find a particular device in
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3 | * /dev
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4 | *
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5 | * Copyright (C) 2000 Theodore Ts'o.
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6 | *
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7 | * %Begin-Header%
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8 | * This file may be redistributed under the terms of the GNU Public
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9 | * License.
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10 | * %End-Header%
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11 | */
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12 |
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13 | #include <stdio.h>
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14 | #include <string.h>
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15 | #if HAVE_UNISTD_H
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16 | #include <unistd.h>
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17 | #endif
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18 | #include <stdlib.h>
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19 | #include <string.h>
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20 | #if HAVE_SYS_TYPES_H
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21 | #include <sys/types.h>
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22 | #endif
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23 | #if HAVE_SYS_STAT_H
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24 | #include <sys/stat.h>
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25 | #endif
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26 | #include <dirent.h>
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27 | #if HAVE_ERRNO_H
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28 | #include <errno.h>
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29 | #endif
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30 | #if HAVE_SYS_MKDEV_H
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31 | #include <sys/mkdev.h>
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32 | #endif
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33 |
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34 | #include "ext2_fs.h"
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35 | #include "ext2fs.h"
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36 |
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37 | struct dir_list {
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38 | char *name;
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39 | struct dir_list *next;
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40 | };
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41 |
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42 | /*
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43 | * This function adds an entry to the directory list
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44 | */
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45 | static void add_to_dirlist(const char *name, struct dir_list **list)
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46 | {
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47 | struct dir_list *dp;
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48 |
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49 | dp = xmalloc(sizeof(struct dir_list));
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50 | dp->name = xmalloc(strlen(name)+1);
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51 | strcpy(dp->name, name);
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52 | dp->next = *list;
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53 | *list = dp;
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54 | }
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55 |
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56 | /*
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57 | * This function frees a directory list
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58 | */
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59 | static void free_dirlist(struct dir_list **list)
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60 | {
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61 | struct dir_list *dp, *next;
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62 |
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63 | for (dp = *list; dp; dp = next) {
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64 | next = dp->next;
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65 | free(dp->name);
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66 | free(dp);
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67 | }
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68 | *list = 0;
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69 | }
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70 |
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71 | static int scan_dir(char *dir_name, dev_t device, struct dir_list **list,
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72 | char **ret_path)
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73 | {
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74 | DIR *dir;
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75 | struct dirent *dp;
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76 | char path[1024], *cp;
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77 | int dirlen;
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78 | struct stat st;
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79 |
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80 | dirlen = strlen(dir_name);
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81 | if ((dir = opendir(dir_name)) == NULL)
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82 | return errno;
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83 | dp = readdir(dir);
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84 | while (dp) {
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85 | if (dirlen + strlen(dp->d_name) + 2 >= sizeof(path))
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86 | goto skip_to_next;
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87 | if (dp->d_name[0] == '.' &&
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88 | ((dp->d_name[1] == 0) ||
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89 | ((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
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90 | goto skip_to_next;
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91 | sprintf(path, "%s/%s", dir_name, dp->d_name);
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92 | if (stat(path, &st) < 0)
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93 | goto skip_to_next;
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94 | if (S_ISDIR(st.st_mode))
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95 | add_to_dirlist(path, list);
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96 | if (S_ISBLK(st.st_mode) && st.st_rdev == device) {
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97 | cp = xmalloc(strlen(path)+1);
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98 | strcpy(cp, path);
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99 | *ret_path = cp;
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100 | goto success;
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101 | }
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102 | skip_to_next:
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103 | dp = readdir(dir);
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104 | }
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105 | success:
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106 | closedir(dir);
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107 | return 0;
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108 | }
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109 |
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110 | /*
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111 | * This function finds the pathname to a block device with a given
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112 | * device number. It returns a pointer to allocated memory to the
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113 | * pathname on success, and NULL on failure.
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114 | */
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115 | char *ext2fs_find_block_device(dev_t device)
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116 | {
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117 | struct dir_list *list = 0, *new_list = 0;
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118 | struct dir_list *current;
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119 | char *ret_path = 0;
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120 |
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121 | /*
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122 | * Add the starting directories to search...
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123 | */
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124 | add_to_dirlist("/devices", &list);
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125 | add_to_dirlist("/devfs", &list);
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126 | add_to_dirlist("/dev", &list);
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127 |
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128 | while (list) {
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129 | current = list;
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130 | list = list->next;
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131 | #ifdef DEBUG
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132 | printf("Scanning directory %s\n", current->name);
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133 | #endif
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134 | scan_dir(current->name, device, &new_list, &ret_path);
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135 | free(current->name);
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136 | free(current);
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137 | if (ret_path)
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138 | break;
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139 | /*
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140 | * If we're done checking at this level, descend to
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141 | * the next level of subdirectories. (breadth-first)
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142 | */
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143 | if (list == 0) {
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144 | list = new_list;
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145 | new_list = 0;
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146 | }
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147 | }
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148 | free_dirlist(&list);
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149 | free_dirlist(&new_list);
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150 | return ret_path;
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151 | }
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152 |
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153 |
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154 | #ifdef DEBUG
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155 | int main(int argc, char** argv)
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156 | {
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157 | char *devname, *tmp;
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158 | int major, minor;
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159 | dev_t device;
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160 | const char *errmsg = "Couldn't parse %s: %s\n";
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161 |
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162 | if ((argc != 2) && (argc != 3)) {
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163 | fprintf(stderr, "Usage: %s device_number\n", argv[0]);
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164 | fprintf(stderr, "\t: %s major minor\n", argv[0]);
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165 | exit(1);
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166 | }
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167 | if (argc == 2) {
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168 | device = strtoul(argv[1], &tmp, 0);
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169 | if (*tmp) {
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170 | fprintf(stderr, errmsg, "device number", argv[1]);
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171 | exit(1);
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172 | }
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173 | } else {
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174 | major = strtoul(argv[1], &tmp, 0);
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175 | if (*tmp) {
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176 | fprintf(stderr, errmsg, "major number", argv[1]);
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177 | exit(1);
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178 | }
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179 | minor = strtoul(argv[2], &tmp, 0);
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180 | if (*tmp) {
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181 | fprintf(stderr, errmsg, "minor number", argv[2]);
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182 | exit(1);
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183 | }
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184 | device = makedev(major, minor);
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185 | printf("Looking for device 0x%04x (%d:%d)\n", device,
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186 | major, minor);
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187 | }
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188 | devname = ext2fs_find_block_device(device);
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189 | if (devname) {
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190 | printf("Found device! %s\n", devname);
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191 | free(devname);
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192 | } else {
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193 | printf("Couldn't find device.\n");
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194 | }
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195 | return 0;
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196 | }
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197 |
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198 | #endif
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