scoutos / prex-0.9.0 / usr / server / fs / fifofs / fifo_vnops.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*
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2 | * Copyright (c) 2008, Kohsuke Ohtani
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the author nor the names of any co-contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | */
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29 | |||
30 | /*
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31 | * fifofs - FIFO/pipe file system.
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32 | */
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33 | |||
34 | #include <sys/prex.h> |
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35 | #include <sys/stat.h> |
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36 | #include <sys/vnode.h> |
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37 | #include <sys/file.h> |
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38 | #include <sys/mount.h> |
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39 | #include <sys/syslog.h> |
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40 | #include <sys/dirent.h> |
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41 | #include <sys/list.h> |
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42 | |||
43 | #include <ctype.h> |
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44 | #include <unistd.h> |
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45 | #include <errno.h> |
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46 | #include <string.h> |
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47 | #include <stdlib.h> |
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48 | #include <limits.h> |
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49 | #include <fcntl.h> |
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50 | |||
51 | #include "fifo.h" |
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52 | |||
53 | struct fifo_node {
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54 | struct list fn_link;
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55 | int fn_type; /* type: VFIFO or VPIPE */ |
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56 | char *fn_name; /* name (null-terminated) */ |
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57 | cond_t fn_rcond; /* cv for read */
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58 | cond_t fn_wcond; /* cv for write */
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59 | mutex_t fn_rmtx; /* mutex for read */
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60 | mutex_t fn_wmtx; /* mutex for write */
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61 | int fn_readers; /* reader count */ |
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62 | int fn_writers; /* writer count */ |
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63 | int fn_start; /* start offset of buffer data */ |
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64 | int fn_size; /* size of buffer data */ |
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65 | char *fn_buf; /* pointer to buffer */ |
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66 | }; |
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67 | |||
68 | #define fifo_mount ((vfsop_mount_t)vfs_nullop)
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69 | #define fifo_unmount ((vfsop_umount_t)vfs_nullop)
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70 | #define fifo_sync ((vfsop_sync_t)vfs_nullop)
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71 | #define fifo_vget ((vfsop_vget_t)vfs_nullop)
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72 | #define fifo_statfs ((vfsop_statfs_t)vfs_nullop)
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73 | |||
74 | static int fifo_open (vnode_t, int); |
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75 | static int fifo_close (vnode_t, file_t); |
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76 | static int fifo_read (vnode_t, file_t, void *, size_t, size_t *); |
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77 | static int fifo_write (vnode_t, file_t, void *, size_t, size_t *); |
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78 | #define fifo_seek ((vnop_seek_t)vop_nullop)
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79 | static int fifo_ioctl (vnode_t, file_t, u_long, void *); |
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80 | #define fifo_fsync ((vnop_fsync_t)vop_nullop)
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81 | static int fifo_readdir (vnode_t, file_t, struct dirent *); |
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82 | static int fifo_lookup (vnode_t, char *, vnode_t); |
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83 | static int fifo_create (vnode_t, char *, mode_t); |
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84 | static int fifo_remove (vnode_t, vnode_t, char *); |
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85 | #define fifo_rename ((vnop_rename_t)vop_einval)
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86 | #define fifo_mkdir ((vnop_mkdir_t)vop_einval)
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87 | #define fifo_rmdir ((vnop_rmdir_t)vop_einval)
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88 | #define fifo_getattr ((vnop_getattr_t)vop_nullop)
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89 | #define fifo_setattr ((vnop_setattr_t)vop_nullop)
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90 | #define fifo_inactive ((vnop_inactive_t)vop_nullop)
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91 | #define fifo_truncate ((vnop_truncate_t)vop_nullop)
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92 | |||
93 | static void cleanup_fifo(vnode_t); |
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94 | static void wait_reader(vnode_t); |
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95 | static void wakeup_reader(vnode_t); |
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96 | static void wait_writer(vnode_t); |
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97 | static void wakeup_writer(vnode_t); |
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98 | |||
99 | #if CONFIG_FS_THREADS > 1 |
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100 | static mutex_t fifo_lock = MUTEX_INITIALIZER;
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101 | #endif
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102 | |||
103 | static struct list fifo_head; |
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104 | |||
105 | /*
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106 | * vnode operations
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107 | */
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108 | struct vnops fifofs_vnops = {
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109 | fifo_open, /* open */
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110 | fifo_close, /* close */
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111 | fifo_read, /* read */
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112 | fifo_write, /* write */
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113 | fifo_seek, /* seek */
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114 | fifo_ioctl, /* ioctl */
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115 | fifo_fsync, /* fsync */
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116 | fifo_readdir, /* readdir */
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117 | fifo_lookup, /* lookup */
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118 | fifo_create, /* create */
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119 | fifo_remove, /* remove */
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120 | fifo_rename, /* remame */
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121 | fifo_mkdir, /* mkdir */
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122 | fifo_rmdir, /* rmdir */
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123 | fifo_getattr, /* getattr */
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124 | fifo_setattr, /* setattr */
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125 | fifo_inactive, /* inactive */
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126 | fifo_truncate, /* truncate */
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127 | }; |
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128 | |||
129 | /*
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130 | * File system operations
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131 | */
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132 | struct vfsops fifofs_vfsops = {
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133 | fifo_mount, /* mount */
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134 | fifo_unmount, /* unmount */
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135 | fifo_sync, /* sync */
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136 | fifo_vget, /* vget */
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137 | fifo_statfs, /* statfs */
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138 | &fifofs_vnops, /* vnops */
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139 | }; |
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140 | |||
141 | static int |
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142 | fifo_open(vnode_t vp, int flags)
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143 | { |
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144 | struct fifo_node *np = vp->v_data;
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145 | |||
146 | DPRINTF(("fifo_open: path=%s\n", vp->v_path));
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147 | |||
148 | if (!strcmp(vp->v_path, "/")) /* root ? */ |
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149 | return 0; |
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150 | |||
151 | /*
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152 | * Unblock all threads who are waiting in open().
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153 | */
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154 | if (flags & FREAD) {
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155 | if (np->fn_readers == 0 && np->fn_writers > 0) |
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156 | wakeup_writer(vp); |
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157 | np->fn_readers++; |
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158 | } |
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159 | if (flags & FWRITE) {
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160 | if (np->fn_writers == 0 && np->fn_readers > 0) |
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161 | wakeup_reader(vp); |
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162 | np->fn_writers++; |
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163 | } |
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164 | |||
165 | /*
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166 | * If no-one opens FIFO at the other side, wait for open().
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167 | */
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168 | if (flags & FREAD) {
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169 | if (flags & O_NONBLOCK) {
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170 | } else {
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171 | while (np->fn_writers == 0) |
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172 | wait_writer(vp); |
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173 | } |
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174 | } |
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175 | if (flags & FWRITE) {
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176 | if (flags & O_NONBLOCK) {
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177 | if (np->fn_readers == 0) |
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178 | return ENXIO;
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179 | } else {
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180 | while (np->fn_readers == 0) |
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181 | wait_reader(vp); |
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182 | } |
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183 | } |
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184 | return 0; |
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185 | } |
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186 | |||
187 | static int |
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188 | fifo_close(vnode_t vp, file_t fp) |
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189 | { |
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190 | struct fifo_node *np = vp->v_data;
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191 | |||
192 | DPRINTF(("fifo_close: fp=%x\n", fp));
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193 | |||
194 | if (np == NULL) |
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195 | return 0; |
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196 | |||
197 | if (fp->f_flags & FREAD) {
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198 | np->fn_readers--; |
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199 | if (np->fn_readers == 0) |
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200 | wakeup_writer(vp); |
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201 | } |
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202 | if (fp->f_flags & FWRITE) {
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203 | np->fn_writers--; |
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204 | if (np->fn_writers == 0) |
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205 | wakeup_reader(vp); |
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206 | } |
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207 | if (vp->v_refcnt > 1) |
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208 | return 0; |
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209 | |||
210 | /* Clearn up pipe */
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211 | if (!strncmp(np->fn_name, "pipe", 4)) { |
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212 | DPRINTF(("fifo_close: remove pipe\n"));
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213 | cleanup_fifo(vp); |
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214 | } |
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215 | return 0; |
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216 | } |
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217 | |||
218 | static int |
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219 | fifo_read(vnode_t vp, file_t fp, void *buf, size_t size, size_t *result)
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220 | { |
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221 | struct fifo_node *np = vp->v_data;
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222 | char *p = buf;
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223 | u_int pos, nbytes; |
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224 | |||
225 | DPRINTF(("fifo_read\n"));
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226 | |||
227 | /*
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228 | * If nothing in the pipe, wait.
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229 | */
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230 | while (np->fn_size == 0) { |
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231 | /*
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232 | * No data and no writer, then EOF
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233 | */
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234 | if (np->fn_writers == 0) { |
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235 | *result = 0;
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236 | return 0; |
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237 | } |
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238 | /*
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239 | * wait for data
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240 | */
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241 | wait_writer(vp); |
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242 | } |
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243 | /*
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244 | * Read
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245 | */
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246 | nbytes = (np->fn_size < size) ? np->fn_size : size; |
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247 | np->fn_size -= nbytes; |
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248 | *result = nbytes; |
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249 | |||
250 | pos = np->fn_start; |
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251 | while (nbytes > 0) { |
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252 | *p++ = np->fn_buf[pos]; |
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253 | if (++pos > PIPE_BUF)
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254 | pos = 0;
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255 | nbytes--; |
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256 | } |
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257 | np->fn_start = pos; |
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258 | |||
259 | wakeup_writer(vp); |
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260 | return 0; |
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261 | } |
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262 | |||
263 | static int |
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264 | fifo_write(vnode_t vp, file_t fp, void *buf, size_t size, size_t *result)
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265 | { |
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266 | struct fifo_node *np = vp->v_data;
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267 | char *p = buf;
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268 | u_int pos, nfree, nbytes, count = 0;
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269 | |||
270 | DPRINTF(("fifo_write\n"));
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271 | |||
272 | again:
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273 | /*
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274 | * If the pipe is full,
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275 | * wait for reads to deplete
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276 | * and truncate it.
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277 | */
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278 | while (np->fn_size >= PIPE_BUF)
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279 | wait_reader(vp); |
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280 | |||
281 | /*
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282 | * Write
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283 | */
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284 | nfree = PIPE_BUF - np->fn_size; |
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285 | nbytes = (nfree < size) ? nfree : size; |
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286 | |||
287 | pos = np->fn_start + np->fn_size; |
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288 | if (pos >= PIPE_BUF)
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289 | pos -= PIPE_BUF; |
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290 | np->fn_size += nbytes; |
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291 | size -= nbytes; |
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292 | while (nbytes > 0) { |
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293 | np->fn_buf[pos] = *p++; |
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294 | if (++pos > PIPE_BUF)
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295 | pos = 0;
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296 | nbytes--; |
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297 | count++; |
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298 | } |
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299 | |||
300 | wakeup_reader(vp); |
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301 | |||
302 | if (size > 0) |
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303 | goto again;
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304 | |||
305 | *result = count; |
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306 | return 0; |
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307 | } |
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308 | |||
309 | static int |
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310 | fifo_ioctl(vnode_t vp, file_t fp, u_long cmd, void *arg)
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311 | { |
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312 | DPRINTF(("fifo_ioctl\n"));
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313 | return EINVAL;
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314 | } |
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315 | |||
316 | static int |
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317 | fifo_lookup(vnode_t dvp, char *name, vnode_t vp)
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318 | { |
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319 | list_t head, n; |
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320 | struct fifo_node *np = NULL; |
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321 | int found;
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322 | |||
323 | DPRINTF(("fifo_lookup: %s\n", name));
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324 | |||
325 | if (*name == '\0') |
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326 | return ENOENT;
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327 | |||
328 | mutex_lock(&fifo_lock); |
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329 | |||
330 | found = 0;
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331 | head = &fifo_head; |
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332 | for (n = list_first(head); n != head; n = list_next(n)) {
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333 | np = list_entry(n, struct fifo_node, fn_link);
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334 | if (strcmp(name, np->fn_name) == 0) { |
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335 | found = 1;
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336 | break;
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337 | } |
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338 | } |
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339 | if (found == 0) { |
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340 | mutex_unlock(&fifo_lock); |
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341 | return ENOENT;
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342 | } |
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343 | vp->v_data = np; |
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344 | vp->v_mode = ALLPERMS; |
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345 | vp->v_size = 0;
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346 | vp->v_type = VFIFO; |
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347 | mutex_unlock(&fifo_lock); |
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348 | return 0; |
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349 | } |
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350 | |||
351 | static int |
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352 | fifo_create(vnode_t dvp, char *name, mode_t mode)
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353 | { |
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354 | struct fifo_node *np;
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355 | size_t len; |
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356 | |||
357 | DPRINTF(("create %s in %s\n", name, dvp->v_path));
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358 | |||
359 | #if 0
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360 | if (!S_ISFIFO(mode))
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361 | return EINVAL;
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362 | #endif
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363 | |||
364 | if ((np = malloc(sizeof(struct fifo_node))) == NULL) |
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365 | return ENOMEM;
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366 | |||
367 | if ((np->fn_buf = malloc(PIPE_BUF)) == NULL) { |
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368 | free(np); |
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369 | return ENOMEM;
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370 | } |
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371 | len = strlen(name) + 1;
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372 | np->fn_name = malloc(len); |
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373 | if (np->fn_name == NULL) { |
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374 | free(np->fn_buf); |
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375 | free(np); |
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376 | return ENOMEM;
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377 | } |
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378 | |||
379 | strlcpy(np->fn_name, name, len); |
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380 | mutex_init(&np->fn_rmtx); |
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381 | mutex_init(&np->fn_wmtx); |
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382 | cond_init(&np->fn_rcond); |
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383 | cond_init(&np->fn_wcond); |
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384 | np->fn_readers = 0;
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385 | np->fn_writers = 0;
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386 | np->fn_start = 0;
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387 | np->fn_size = 0;
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388 | |||
389 | mutex_lock(&fifo_lock); |
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390 | list_insert(&fifo_head, &np->fn_link); |
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391 | mutex_unlock(&fifo_lock); |
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392 | return 0; |
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393 | } |
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394 | |||
395 | static void |
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396 | cleanup_fifo(vnode_t vp) |
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397 | { |
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398 | struct fifo_node *np = vp->v_data;
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399 | |||
400 | mutex_lock(&fifo_lock); |
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401 | list_remove(&np->fn_link); |
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402 | mutex_unlock(&fifo_lock); |
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403 | |||
404 | free(np->fn_name); |
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405 | free(np->fn_buf); |
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406 | free(np); |
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407 | |||
408 | vp->v_data = NULL;
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409 | } |
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410 | |||
411 | static int |
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412 | fifo_remove(vnode_t dvp, vnode_t vp, char *name)
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413 | { |
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414 | DPRINTF(("remove %s in %s\n", name, dvp->v_path));
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415 | |||
416 | cleanup_fifo(vp); |
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417 | return 0; |
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418 | } |
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419 | |||
420 | /*
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421 | * @vp: vnode of the directory.
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422 | */
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423 | static int |
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424 | fifo_readdir(vnode_t vp, file_t fp, struct dirent *dir)
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425 | { |
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426 | struct fifo_node *np;
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427 | list_t head, n; |
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428 | int i;
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429 | |||
430 | mutex_lock(&fifo_lock); |
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431 | |||
432 | if (fp->f_offset == 0) { |
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433 | dir->d_type = DT_DIR; |
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434 | strlcpy((char *)&dir->d_name, ".", sizeof(dir->d_name)); |
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435 | } else if (fp->f_offset == 1) { |
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436 | dir->d_type = DT_DIR; |
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437 | strlcpy((char *)&dir->d_name, "..", sizeof(dir->d_name)); |
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438 | } else {
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439 | i = 0;
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440 | np = NULL;
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441 | head = &fifo_head; |
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442 | for (n = list_first(head); n != head; n = list_next(n)) {
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443 | if (i == (fp->f_offset - 2)) { |
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444 | np = list_entry(n, struct fifo_node, fn_link);
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445 | break;
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446 | } |
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447 | } |
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448 | if (np == NULL) { |
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449 | mutex_unlock(&fifo_lock); |
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450 | return ENOENT;
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451 | } |
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452 | dir->d_type = DT_FIFO; |
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453 | strlcpy((char *)&dir->d_name, np->fn_name,
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454 | sizeof(dir->d_name));
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455 | } |
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456 | dir->d_fileno = fp->f_offset; |
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457 | dir->d_namlen = (uint16_t)strlen(dir->d_name); |
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458 | |||
459 | fp->f_offset++; |
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460 | |||
461 | mutex_unlock(&fifo_lock); |
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462 | return 0; |
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463 | } |
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464 | |||
465 | int
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466 | fifofs_init(void)
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467 | { |
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468 | list_init(&fifo_head); |
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469 | return 0; |
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470 | } |
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471 | |||
472 | |||
473 | static void |
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474 | wait_reader(vnode_t vp) |
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475 | { |
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476 | struct fifo_node *np = vp->v_data;
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477 | |||
478 | DPRINTF(("wait_reader: %x\n", np));
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479 | vn_unlock(vp); |
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480 | mutex_lock(&np->fn_rmtx); |
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481 | cond_wait(&np->fn_rcond, &np->fn_rmtx); |
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482 | mutex_unlock(&np->fn_rmtx); |
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483 | vn_lock(vp); |
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484 | } |
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485 | |||
486 | static void |
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487 | wakeup_writer(vnode_t vp) |
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488 | { |
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489 | struct fifo_node *np = vp->v_data;
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490 | |||
491 | DPRINTF(("wakeup_writer: %x\n", np));
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492 | cond_broadcast(&np->fn_rcond); |
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493 | } |
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494 | |||
495 | static void |
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496 | wait_writer(vnode_t vp) |
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497 | { |
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498 | struct fifo_node *np = vp->v_data;
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499 | |||
500 | DPRINTF(("wait_writer: %x\n", np));
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501 | vn_unlock(vp); |
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502 | mutex_lock(&np->fn_wmtx); |
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503 | cond_wait(&np->fn_wcond, &np->fn_wmtx); |
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504 | mutex_unlock(&np->fn_wmtx); |
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505 | vn_lock(vp); |
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506 | } |
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507 | |||
508 | static void |
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509 | wakeup_reader(vnode_t vp) |
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510 | { |
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511 | struct fifo_node *np = vp->v_data;
|
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512 | |||
513 | DPRINTF(("wakeup_reader: %x\n", np));
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514 | cond_broadcast(&np->fn_wcond); |
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515 | } |