1 | /**************************************** |
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2 | * Computer Algebra System SINGULAR * |
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3 | ****************************************/ |
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4 | /* $id:$ */ |
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5 | |
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6 | /* find_exec.c -- Find a program, given an argv[0] |
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7 | Copyright (C) 1996 Free Software Foundation, Inc. |
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8 | Copyright (C) 1990 by W. Wilson Ho. |
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9 | This file is part of the GNU Dld Library. */ |
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10 | |
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11 | /* Adapted for use with Singular by obachman@mathematik.uni-kl.de 4/98*/ |
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12 | |
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13 | #include "mod2.h" |
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14 | |
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15 | #if ! defined(MSDOS) && ! defined(__MWERKS__) |
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16 | |
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17 | #include <unistd.h> /* always defiend */ |
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18 | #include <stdlib.h> |
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19 | #include <string.h> |
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20 | |
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21 | #if !defined(ESINGULAR) && !defined(TSINGULAR) |
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22 | #include "mmemory.h" |
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23 | #endif |
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24 | |
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25 | |
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26 | #ifndef MAXPATHLEN |
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27 | #define MAXPATHLEN 1024 |
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28 | #endif |
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29 | |
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30 | /* Do not return copies of sth, but simply the strings |
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31 | -- we make copies later */ |
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32 | #define copy_of(string) mstrdup(string) |
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33 | |
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34 | /* ABSOLUTE_FILENAME_P (fname): True if fname is an absolute filename */ |
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35 | #ifdef atarist |
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36 | #define ABSOLUTE_FILENAME_P(fname) ((fname[0] == '/') || \ |
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37 | (fname[0] && (fname[1] == ':'))) |
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38 | #else |
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39 | #define ABSOLUTE_FILENAME_P(fname) (fname[0] == '/') |
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40 | #endif /* atarist */ |
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41 | |
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42 | /* Return the absolute name of the program named NAME. This function |
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43 | searches the directories in the PATH environment variable if PROG |
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44 | has no directory components. */ |
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45 | #ifndef HAVE_READLINK |
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46 | char * find_executable (const char *name) |
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47 | #else |
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48 | char * find_executable_link (const char *name) |
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49 | #endif |
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50 | { |
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51 | char *search; |
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52 | char *p; |
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53 | #ifdef WINNT |
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54 | char *extra = NULL; |
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55 | #endif |
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56 | char tbuf[MAXPATHLEN]; |
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57 | |
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58 | if (ABSOLUTE_FILENAME_P(name)) |
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59 | { |
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60 | /* If we can execute the named file then return it. */ |
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61 | if (! access (name, X_OK)) |
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62 | return copy_of (name); |
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63 | } |
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64 | else |
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65 | { |
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66 | if (((name[0] == '.') && (name[1] == '/')) || |
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67 | ((name[0] == '.') && (name[1] == '.') && (name[2] == '/')) || |
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68 | strchr(name, '/') != NULL) |
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69 | { |
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70 | |
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71 | #ifdef HAVE_GETCWD |
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72 | getcwd (tbuf, MAXPATHLEN); |
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73 | #else |
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74 | # ifdef HAVE_GETWD |
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75 | getwd (tbuf); |
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76 | # endif |
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77 | #endif |
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78 | strcat (tbuf, "/"); |
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79 | strcat (tbuf, name); |
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80 | if (! access(name, X_OK)) |
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81 | return copy_of (tbuf); |
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82 | } |
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83 | |
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84 | search = getenv("PATH"); |
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85 | /* for winnt under msdos, cwd is implictly in the path */ |
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86 | #ifdef WINNT |
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87 | p = getenv("SHELL"); |
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88 | if (p == NULL || strlen(p) < 2) |
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89 | { |
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90 | /* we are under msdos display */ |
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91 | extra = (char*) AllocL((search != NULL ? strlen(search) : 0) + 3); |
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92 | strcpy(extra, ".:"); |
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93 | if (search != NULL) strcat(extra, search); |
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94 | search = extra; |
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95 | } |
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96 | #endif |
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97 | p = search; |
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98 | |
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99 | if (p != NULL) |
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100 | { |
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101 | while (1) |
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102 | { |
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103 | char *next; |
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104 | next = tbuf; |
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105 | |
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106 | /* Copy directory name into [tbuf]. */ |
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107 | /* This is somewhat tricky: empty names mean cwd, w.r.t. some |
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108 | shell spec */ |
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109 | while (*p && *p != ':') |
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110 | *next ++ = *p ++; |
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111 | *next = '\0'; |
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112 | |
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113 | if ((tbuf[0] == '.' && tbuf[1] == '\0') || tbuf[0] == '\0') { |
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114 | #ifdef HAVE_GETCWD |
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115 | getcwd (tbuf, MAXPATHLEN); |
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116 | #else |
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117 | # ifdef HAVE_GETWD |
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118 | getwd (tbuf); |
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119 | # endif |
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120 | #endif |
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121 | } |
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122 | |
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123 | if (tbuf[strlen(tbuf)-1] != '/') strcat(tbuf, "/"); |
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124 | strcat (tbuf, name); |
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125 | |
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126 | /* If we can execute the named file, then return it. */ |
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127 | if (! access (tbuf, X_OK)) |
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128 | { |
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129 | #ifdef WINNT |
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130 | if (extra != NULL) |
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131 | FreeL(extra); |
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132 | #endif |
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133 | return copy_of (tbuf); |
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134 | } |
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135 | |
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136 | if (*p != '\0') |
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137 | { |
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138 | p ++; |
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139 | } |
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140 | else |
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141 | { |
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142 | break; |
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143 | } |
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144 | |
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145 | } |
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146 | } |
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147 | } |
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148 | |
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149 | return NULL; |
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150 | } |
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151 | |
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152 | #ifdef HAVE_READLINK |
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153 | |
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154 | /* similar to readlink, but dont' mess up absolute pathnames */ |
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155 | int my_readlink(const char* name, char* buf, size_t bufsize) |
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156 | { |
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157 | char buf2[MAXPATHLEN]; |
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158 | int ret; |
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159 | |
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160 | if ((ret = readlink(name, buf2, bufsize)) > 0) |
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161 | { |
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162 | buf2[ret] = 0; |
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163 | if (*name == '/' && *buf2 != '/') |
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164 | { |
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165 | char* last = strrchr(name, '/'); |
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166 | int i = 0; |
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167 | while (&(name[i]) != last) |
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168 | { |
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169 | buf[i] = name[i]; |
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170 | i++; |
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171 | } |
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172 | buf[i] = '/'; |
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173 | i++; |
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174 | strcpy(&(buf[i]), buf2); |
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175 | return i + ret; |
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176 | } |
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177 | else |
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178 | { |
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179 | strcpy(buf, buf2); |
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180 | } |
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181 | } |
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182 | return ret; |
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183 | } |
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184 | |
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185 | #define MAX_LINK_LEVEL 10 |
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186 | /* similar to readlink (cf. man readlink), except that symbolic links are |
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187 | followed up to MAX_LINK_LEVEL |
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188 | */ |
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189 | |
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190 | int full_readlink(const char* name, char* buf, size_t bufsize) |
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191 | { |
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192 | int ret; |
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193 | |
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194 | if ((ret=my_readlink(name, buf, bufsize)) > 0) |
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195 | { |
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196 | char buf2[MAXPATHLEN]; |
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197 | int ret2, i = 0; |
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198 | |
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199 | do |
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200 | { |
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201 | buf[ret] = '\0'; |
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202 | if ((ret2 = my_readlink(buf, buf2, MAXPATHLEN)) > 0) |
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203 | { |
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204 | i++; |
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205 | buf2[ret2] = '\0'; |
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206 | strcpy(buf, buf2); |
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207 | ret = ret2; |
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208 | } |
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209 | else |
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210 | { |
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211 | return ret; |
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212 | } |
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213 | } |
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214 | while (i<MAX_LINK_LEVEL); |
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215 | } |
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216 | return -1; |
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217 | } |
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218 | |
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219 | |
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220 | char * find_executable (const char *name) |
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221 | { |
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222 | char * link = find_executable_link(name); |
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223 | char buf[MAXPATHLEN]; |
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224 | int ret; |
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225 | |
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226 | if (link == NULL && (ret=full_readlink(name, buf, MAXPATHLEN)) > 0) |
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227 | { |
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228 | buf[ret] ='\0'; |
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229 | link = find_executable_link(buf); |
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230 | } |
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231 | if (link != NULL && (ret=full_readlink(link, buf, MAXPATHLEN)) > 0) |
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232 | { |
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233 | char *p = strrchr(link, '/'); |
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234 | char *executable; |
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235 | |
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236 | |
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237 | if(p!=NULL) *(p+1)='\0'; |
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238 | buf[ret]='\0'; |
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239 | |
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240 | if (buf[0] != '/') |
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241 | { |
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242 | executable = (char*) AllocL(strlen(link) + ret + 1); |
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243 | strcpy(executable, link); |
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244 | strcat(executable, buf); |
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245 | } |
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246 | else |
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247 | { |
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248 | executable = copy_of(buf); |
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249 | } |
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250 | |
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251 | FreeL(link); |
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252 | return executable; |
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253 | } |
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254 | |
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255 | return link; |
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256 | } |
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257 | #endif /* HAVE_READLINK */ |
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258 | |
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259 | #else |
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260 | |
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261 | char* find_executable (const char *name) |
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262 | { |
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263 | return NULL; |
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264 | } |
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265 | |
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266 | #endif /* #if ! defined(MSDOS) && ! defined(__MWERKS__) && defined(HAVE_SYS_TYPES_H) && defined(HAVE_PWD_H)&&defined(HAVE_SYS_PARAM_H) */ |
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267 | |
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268 | |
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