root / prex-0.9.0 / usr / server / fs / vfs / vfs_task.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*-
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2 | * Copyright (c) 2007, Kohsuke Ohtani All rights reserved.
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3 | *
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4 | * Redistribution and use in source and binary forms, with or without
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5 | * modification, are permitted provided that the following conditions
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6 | * are met:
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7 | * 1. Redistributions of source code must retain the above copyright
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8 | * notice, this list of conditions and the following disclaimer.
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9 | * 2. Redistributions in binary form must reproduce the above copyright
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10 | * notice, this list of conditions and the following disclaimer in the
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11 | * documentation and/or other materials provided with the distribution.
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12 | * 3. Neither the name of the author nor the names of any co-contributors
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13 | * may be used to endorse or promote products derived from this software
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14 | * without specific prior written permission.
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15 | *
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16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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17 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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20 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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21 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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22 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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23 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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24 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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25 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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26 | * SUCH DAMAGE.
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27 | */
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28 | |||
29 | /*
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30 | * vfs_task.c - Routines to manage the per task data.
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31 | */
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32 | |||
33 | #include <sys/prex.h> |
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34 | #include <sys/list.h> |
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35 | |||
36 | #include <limits.h> |
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37 | #include <stdlib.h> |
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38 | #include <string.h> |
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39 | #include <stdio.h> |
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40 | #include <errno.h> |
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41 | |||
42 | #include "vfs.h" |
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43 | |||
44 | #define TASK_MAXBUCKETS 32 /* number of task hash buckets */ |
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45 | |||
46 | #define TASKHASH(x) (int)((x) & (TASK_MAXBUCKETS - 1)) |
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47 | |||
48 | /*
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49 | * Hash table for task.
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50 | */
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51 | static struct list task_table[TASK_MAXBUCKETS]; |
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52 | |||
53 | /*
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54 | * Global lock for task access.
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55 | */
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56 | #if CONFIG_FS_THREADS > 1 |
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57 | static mutex_t task_lock = MUTEX_INITIALIZER;
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58 | #define TASK_LOCK() mutex_lock(&task_lock)
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59 | #define TASK_UNLOCK() mutex_unlock(&task_lock)
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60 | #else
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61 | #define TASK_LOCK()
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62 | #define TASK_UNLOCK()
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63 | #endif
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64 | |||
65 | /*
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66 | * Convert task ID to a task structure.
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67 | * Returns locked task. Caller must unlock it after using it.
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68 | */
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69 | struct task *
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70 | task_lookup(task_t task) |
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71 | { |
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72 | list_t head, n; |
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73 | struct task *t;
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74 | |||
75 | if (task == TASK_NULL)
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76 | return NULL; |
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77 | |||
78 | TASK_LOCK(); |
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79 | head = &task_table[TASKHASH(task)]; |
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80 | for (n = list_first(head); n != head; n = list_next(n)) {
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81 | t = list_entry(n, struct task, t_link);
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82 | ASSERT(t->t_taskid); |
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83 | if (t->t_taskid == task) {
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84 | TASK_UNLOCK(); |
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85 | mutex_lock(&t->t_lock); |
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86 | return t;
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87 | } |
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88 | } |
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89 | TASK_UNLOCK(); |
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90 | |||
91 | /* Not found */
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92 | return NULL; |
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93 | } |
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94 | |||
95 | /*
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96 | * Allocate new task.
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97 | */
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98 | int
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99 | task_alloc(task_t task, struct task **pt)
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100 | { |
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101 | struct task *t;
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102 | |||
103 | /* Check if specified task already exists. */
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104 | if (task_lookup(task) != NULL) |
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105 | return EINVAL;
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106 | |||
107 | if (!(t = malloc(sizeof(struct task)))) |
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108 | return ENOMEM;
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109 | memset(t, 0, sizeof(struct task)); |
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110 | t->t_taskid = task; |
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111 | strlcpy(t->t_cwd, "/", sizeof(t->t_cwd)); |
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112 | mutex_init(&t->t_lock); |
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113 | |||
114 | TASK_LOCK(); |
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115 | list_insert(&task_table[TASKHASH(task)], &t->t_link); |
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116 | TASK_UNLOCK(); |
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117 | *pt = t; |
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118 | return 0; |
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119 | } |
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120 | |||
121 | /*
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122 | * Free task and related resource.
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123 | */
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124 | void
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125 | task_free(struct task *t)
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126 | { |
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127 | |||
128 | TASK_LOCK(); |
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129 | list_remove(&t->t_link); |
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130 | mutex_unlock(&t->t_lock); |
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131 | mutex_destroy(&t->t_lock); |
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132 | free(t); |
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133 | TASK_UNLOCK(); |
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134 | } |
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135 | |||
136 | /*
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137 | * Set task id of the specified task.
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138 | */
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139 | void
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140 | task_setid(struct task *t, task_t task)
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141 | { |
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142 | |||
143 | TASK_LOCK(); |
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144 | list_remove(&t->t_link); |
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145 | t->t_taskid = task; |
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146 | list_insert(&task_table[TASKHASH(task)], &t->t_link); |
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147 | TASK_UNLOCK(); |
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148 | } |
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149 | |||
150 | /*
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151 | * Unlock task.
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152 | */
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153 | void
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154 | task_unlock(struct task *t)
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155 | { |
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156 | |||
157 | mutex_unlock(&t->t_lock); |
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158 | } |
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159 | |||
160 | /*
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161 | * Convert a file descriptor into a pointer
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162 | * to a file structre.
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163 | */
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164 | file_t |
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165 | task_getfp(struct task *t, int fd) |
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166 | { |
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167 | |||
168 | if (fd < 0 || fd >= OPEN_MAX) |
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169 | return NULL; |
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170 | |||
171 | return t->t_ofile[fd];
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172 | } |
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173 | |||
174 | /*
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175 | * Set file pointer for task/fd pair.
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176 | */
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177 | void
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178 | task_setfp(struct task *t, int fd, file_t fp) |
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179 | { |
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180 | |||
181 | t->t_ofile[fd] = fp; |
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182 | } |
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183 | |||
184 | /*
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185 | * Get new file descriptor in the task.
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186 | * Returns -1 if there is no empty slot.
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187 | */
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188 | int
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189 | task_newfd(struct task *t)
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190 | { |
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191 | int fd;
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192 | |||
193 | /*
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194 | * Find the smallest empty slot in the fd array.
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195 | */
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196 | for (fd = 0; fd < OPEN_MAX; fd++) { |
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197 | if (t->t_ofile[fd] == NULL) |
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198 | break;
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199 | } |
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200 | if (fd == OPEN_MAX)
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201 | return -1; /* slot full */ |
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202 | |||
203 | return fd;
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204 | } |
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205 | |||
206 | /*
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207 | * Delete a file descriptor.
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208 | */
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209 | void
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210 | task_delfd(struct task *t, int fd) |
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211 | { |
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212 | |||
213 | t->t_ofile[fd] = NULL;
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214 | } |
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215 | |||
216 | /*
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217 | * Convert to full path from the cwd of task and path.
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218 | * @t: task structure
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219 | * @path: target path
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220 | * @full: full path to be returned
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221 | * @acc: access mode
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222 | */
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223 | int
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224 | task_conv(struct task *t, char *path, int acc, char *full) |
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225 | { |
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226 | char *src, *tgt, *p, *end, *cwd;
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227 | size_t len = 0;
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228 | |||
229 | cwd = t->t_cwd; |
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230 | path[PATH_MAX - 1] = '\0'; |
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231 | len = strlen(path); |
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232 | if (len >= PATH_MAX)
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233 | return ENAMETOOLONG;
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234 | if (strlen(cwd) + len >= PATH_MAX)
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235 | return ENAMETOOLONG;
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236 | src = path; |
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237 | tgt = full; |
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238 | end = src + len; |
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239 | if (path[0] == '/') { |
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240 | *tgt++ = *src++; |
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241 | len++; |
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242 | } else {
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243 | strlcpy(full, cwd, PATH_MAX); |
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244 | len = strlen(cwd); |
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245 | tgt += len; |
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246 | if (len > 1 && path[0] != '.') { |
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247 | *tgt = '/';
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248 | tgt++; |
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249 | len++; |
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250 | } |
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251 | } |
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252 | while (*src) {
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253 | p = src; |
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254 | while (*p != '/' && *p != '\0') |
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255 | p++; |
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256 | *p = '\0';
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257 | if (!strcmp(src, "..")) { |
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258 | if (len >= 2) { |
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259 | len -= 2;
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260 | tgt -= 2; /* skip previous '/' */ |
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261 | while (*tgt != '/') { |
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262 | tgt--; |
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263 | len--; |
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264 | } |
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265 | if (len == 0) { |
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266 | tgt++; |
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267 | len++; |
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268 | } |
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269 | } |
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270 | } else if (!strcmp(src, ".")) { |
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271 | /* Ignore "." */
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272 | } else {
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273 | while (*src != '\0') { |
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274 | *tgt++ = *src++; |
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275 | len++; |
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276 | } |
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277 | } |
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278 | if (p == end)
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279 | break;
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280 | if (len > 0 && *(tgt - 1) != '/') { |
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281 | *tgt++ = '/';
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282 | len++; |
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283 | } |
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284 | src = p + 1;
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285 | } |
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286 | *tgt = '\0';
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287 | |||
288 | /* Check if the client task has required permission */
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289 | return sec_file_permission(t->t_taskid, full, acc);
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290 | } |
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291 | |||
292 | #ifdef DEBUG_VFS
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293 | void
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294 | task_dump(void)
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295 | { |
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296 | list_t head, n; |
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297 | struct task *t;
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298 | int i;
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299 | |||
300 | TASK_LOCK(); |
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301 | dprintf("Dump file data\n");
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302 | dprintf(" task opens cwd\n");
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303 | dprintf(" -------- ------- ------------------------------\n");
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304 | for (i = 0; i < TASK_MAXBUCKETS; i++) { |
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305 | head = &task_table[i]; |
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306 | for (n = list_first(head); n != head; n = list_next(n)) {
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307 | t = list_entry(n, struct task, t_link);
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308 | dprintf(" %08x %7x %s\n", (int)t->t_taskid, t->t_nopens, |
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309 | t->t_cwd); |
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310 | } |
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311 | } |
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312 | dprintf("\n");
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313 | TASK_UNLOCK(); |
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314 | } |
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315 | #endif
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316 | |||
317 | void
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318 | task_init(void)
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319 | { |
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320 | int i;
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321 | |||
322 | for (i = 0; i < TASK_MAXBUCKETS; i++) |
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323 | list_init(&task_table[i]); |
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324 | } |