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1 | /* |
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2 | * libev select fd activity backend |
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3 | * |
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4 | * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de> |
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5 | * All rights reserved. |
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6 | * |
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7 | * Redistribution and use in source and binary forms, with or without |
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8 | * modification, are permitted provided that the following conditions are |
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9 | * met: |
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10 | * |
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11 | * * Redistributions of source code must retain the above copyright |
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12 | * notice, this list of conditions and the following disclaimer. |
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13 | * |
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14 | * * Redistributions in binary form must reproduce the above |
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15 | * copyright notice, this list of conditions and the following |
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16 | * disclaimer in the documentation and/or other materials provided |
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17 | * with the distribution. |
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18 | * |
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19 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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20 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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21 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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22 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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23 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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24 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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25 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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26 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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27 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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28 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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29 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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30 | */ |
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31 | |
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32 | /* for broken bsd's */ |
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33 | #include <sys/time.h> |
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34 | #include <sys/types.h> |
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35 | #include <unistd.h> |
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36 | |
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37 | /* for unix systems */ |
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38 | #include <sys/select.h> |
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39 | |
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40 | #include <string.h> |
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41 | #include <inttypes.h> |
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42 | |
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43 | static unsigned char *vec_ri, *vec_ro, *vec_wi, *vec_wo; |
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44 | static int vec_max; |
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45 | |
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46 | static void |
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47 | select_modify (int fd, int oev, int nev) |
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48 | { |
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49 | int offs = fd >> 3; |
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50 | int mask = 1 << (fd & 7); |
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51 | |
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52 | if (vec_max < (fd >> 5) + 1) |
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53 | { |
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54 | int new_max = (fd >> 5) + 1; |
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55 | |
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56 | vec_ri = (unsigned char *)realloc (vec_ri, new_max * 4); |
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57 | vec_ro = (unsigned char *)realloc (vec_ro, new_max * 4); /* could free/malloc */ |
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58 | vec_wi = (unsigned char *)realloc (vec_wi, new_max * 4); |
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59 | vec_wo = (unsigned char *)realloc (vec_wo, new_max * 4); /* could free/malloc */ |
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60 | |
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61 | for (; vec_max < new_max; ++vec_max) |
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62 | ((uint32_t *)vec_ri)[vec_max] = |
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63 | ((uint32_t *)vec_wi)[vec_max] = 0; |
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64 | } |
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65 | |
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66 | vec_ri [offs] |= mask; |
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67 | if (!(nev & EV_READ)) |
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68 | vec_ri [offs] &= ~mask; |
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69 | |
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70 | vec_wi [offs] |= mask; |
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71 | if (!(nev & EV_WRITE)) |
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72 | vec_wi [offs] &= ~mask; |
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73 | } |
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74 | |
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75 | static void |
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76 | select_poll (ev_tstamp timeout) |
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77 | { |
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78 | struct timeval tv; |
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79 | int res; |
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80 | |
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81 | memcpy (vec_ro, vec_ri, vec_max * 4); |
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82 | memcpy (vec_wo, vec_wi, vec_max * 4); |
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83 | |
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84 | tv.tv_sec = (long)timeout; |
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85 | tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6); |
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86 | |
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87 | res = select (vec_max * 32, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv); |
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88 | |
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89 | if (res > 0) |
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90 | { |
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91 | int word, offs; |
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92 | |
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93 | for (word = vec_max; word--; ) |
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94 | { |
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95 | if (((uint32_t *)vec_ro) [word] | ((uint32_t *)vec_wo) [word]) |
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96 | for (offs = 4; offs--; ) |
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97 | { |
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98 | int idx = word * 4 + offs; |
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99 | unsigned char byte_r = vec_ro [idx]; |
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100 | unsigned char byte_w = vec_wo [idx]; |
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101 | int bit; |
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102 | |
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103 | if (byte_r | byte_w) |
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104 | for (bit = 8; bit--; ) |
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105 | { |
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106 | int events = 0; |
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107 | events |= byte_r & (1 << bit) ? EV_READ : 0; |
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108 | events |= byte_w & (1 << bit) ? EV_WRITE : 0; |
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109 | |
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110 | if (events) |
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111 | fd_event (idx * 8 + bit, events); |
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112 | } |
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113 | } |
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114 | } |
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115 | } |
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116 | else if (res < 0) |
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117 | { |
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118 | if (errno == EBADF) |
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119 | fd_ebadf (); |
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120 | else if (errno == ENOMEM) |
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121 | fd_enomem (); |
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122 | } |
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123 | } |
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124 | |
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125 | static void |
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126 | select_init (int flags) |
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127 | { |
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128 | ev_method = EVMETHOD_SELECT; |
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129 | method_fudge = 1e-2; /* needed to compensate for select returning early, very conservative */ |
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130 | method_modify = select_modify; |
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131 | method_poll = select_poll; |
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132 | } |
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133 | |
