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1 /* |
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2 * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 */ |
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23 |
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24 #include "precompiled.hpp" |
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25 #include "gc/z/zArray.inline.hpp" |
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26 #include "gc/z/zBackingPath_linux.hpp" |
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27 #include "gc/z/zErrno.hpp" |
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28 #include "logging/log.hpp" |
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29 |
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30 #include <stdio.h> |
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31 #include <unistd.h> |
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32 |
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33 // Mount information, see proc(5) for more details. |
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34 #define PROC_SELF_MOUNTINFO "/proc/self/mountinfo" |
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35 |
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36 ZBackingPath::ZBackingPath(const char* filesystem, const char** preferred_mountpoints) { |
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37 if (ZPath != NULL) { |
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38 // Use specified path |
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39 _path = strdup(ZPath); |
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40 } else { |
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41 // Find suitable path |
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42 _path = find_mountpoint(filesystem, preferred_mountpoints); |
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43 } |
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44 } |
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45 |
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46 ZBackingPath::~ZBackingPath() { |
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47 free(_path); |
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48 _path = NULL; |
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49 } |
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50 |
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51 char* ZBackingPath::get_mountpoint(const char* line, const char* filesystem) const { |
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52 char* line_mountpoint = NULL; |
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53 char* line_filesystem = NULL; |
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54 |
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55 // Parse line and return a newly allocated string containing the mount point if |
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56 // the line contains a matching filesystem and the mount point is accessible by |
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57 // the current user. |
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58 if (sscanf(line, "%*u %*u %*u:%*u %*s %ms %*[^-]- %ms", &line_mountpoint, &line_filesystem) != 2 || |
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59 strcmp(line_filesystem, filesystem) != 0 || |
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60 access(line_mountpoint, R_OK|W_OK|X_OK) != 0) { |
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61 // Not a matching or accessible filesystem |
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62 free(line_mountpoint); |
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63 line_mountpoint = NULL; |
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64 } |
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65 |
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66 free(line_filesystem); |
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67 |
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68 return line_mountpoint; |
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69 } |
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70 |
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71 void ZBackingPath::get_mountpoints(const char* filesystem, ZArray<char*>* mountpoints) const { |
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72 FILE* fd = fopen(PROC_SELF_MOUNTINFO, "r"); |
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73 if (fd == NULL) { |
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74 ZErrno err; |
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75 log_error(gc)("Failed to open %s: %s", PROC_SELF_MOUNTINFO, err.to_string()); |
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76 return; |
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77 } |
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78 |
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79 char* line = NULL; |
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80 size_t length = 0; |
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81 |
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82 while (getline(&line, &length, fd) != -1) { |
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83 char* const mountpoint = get_mountpoint(line, filesystem); |
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84 if (mountpoint != NULL) { |
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85 mountpoints->add(mountpoint); |
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86 } |
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87 } |
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88 |
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89 free(line); |
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90 fclose(fd); |
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91 } |
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92 |
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93 void ZBackingPath::free_mountpoints(ZArray<char*>* mountpoints) const { |
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94 ZArrayIterator<char*> iter(mountpoints); |
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95 for (char* mountpoint; iter.next(&mountpoint);) { |
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96 free(mountpoint); |
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97 } |
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98 mountpoints->clear(); |
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99 } |
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100 |
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101 char* ZBackingPath::find_preferred_mountpoint(const char* filesystem, |
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102 ZArray<char*>* mountpoints, |
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103 const char** preferred_mountpoints) const { |
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104 // Find preferred mount point |
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105 ZArrayIterator<char*> iter1(mountpoints); |
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106 for (char* mountpoint; iter1.next(&mountpoint);) { |
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107 for (const char** preferred = preferred_mountpoints; *preferred != NULL; preferred++) { |
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108 if (!strcmp(mountpoint, *preferred)) { |
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109 // Preferred mount point found |
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110 return strdup(mountpoint); |
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111 } |
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112 } |
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113 } |
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114 |
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115 // Preferred mount point not found |
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116 log_error(gc)("More than one %s filesystem found:", filesystem); |
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117 ZArrayIterator<char*> iter2(mountpoints); |
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118 for (char* mountpoint; iter2.next(&mountpoint);) { |
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119 log_error(gc)(" %s", mountpoint); |
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120 } |
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121 |
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122 return NULL; |
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123 } |
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124 |
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125 char* ZBackingPath::find_mountpoint(const char* filesystem, const char** preferred_mountpoints) const { |
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126 char* path = NULL; |
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127 ZArray<char*> mountpoints; |
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128 |
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129 get_mountpoints(filesystem, &mountpoints); |
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130 |
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131 if (mountpoints.size() == 0) { |
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132 // No mount point found |
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133 log_error(gc)("Failed to find an accessible %s filesystem", filesystem); |
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134 } else if (mountpoints.size() == 1) { |
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135 // One mount point found |
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136 path = strdup(mountpoints.at(0)); |
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137 } else { |
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138 // More than one mount point found |
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139 path = find_preferred_mountpoint(filesystem, &mountpoints, preferred_mountpoints); |
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140 } |
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141 |
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142 free_mountpoints(&mountpoints); |
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143 |
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144 return path; |
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145 } |
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146 |
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147 const char* ZBackingPath::get() const { |
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148 return _path; |
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149 } |