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3265 | post | 1 | /* Copyright (c) 2008, Tim Post <tinkertim@gmail.com> |
2 | * 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 are met: |
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6 | * |
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7 | * Redistributions of source code must retain the above copyright notice, this |
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8 | * list of conditions and the following disclaimer. |
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9 | * |
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10 | * Redistributions in binary form must reproduce the above copyright notice, |
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11 | * this list of conditions and the following disclaimer in the documentation |
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12 | * and/or other materials provided with the distribution. |
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13 | * |
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14 | * Neither the name of the original program's authors nor the names of its |
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15 | * contributors may be used to endorse or promote products derived from this |
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16 | * software without specific prior written permission. |
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17 | * |
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18 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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19 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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20 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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21 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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22 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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23 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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24 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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25 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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26 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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27 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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28 | * POSSIBILITY OF SUCH DAMAGE. |
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29 | */ |
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30 | |||
31 | /* The VERY basics of execute in place support. These are buggy, leaky |
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32 | * and not nearly done. Only here for beta testing!! You were warned!! |
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33 | * TODO: |
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34 | * Hash command lookups to save time |
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35 | * Create a running pointer to **path and advance/rewind it as we go */ |
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36 | |||
37 | #include <stdio.h> |
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38 | #include <stdlib.h> |
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39 | #include <unistd.h> |
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40 | #include <string.h> |
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41 | #include <fcntl.h> |
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42 | |||
43 | #ifndef HELENOS |
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44 | #include <linux/limits.h> |
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45 | #include <sys/errno.h> |
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46 | #include <sys/wait.h> |
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47 | #endif |
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48 | |||
49 | #include "config.h" |
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50 | #include "util.h" |
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51 | #include "exec.h" |
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52 | #include "errors.h" |
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53 | |||
3298 | post | 54 | /* TODO: create exec, exev, execve wrappers for task_spawn() */ |
55 | |||
56 | /* Easiest way to handle a shared + allocated string */ |
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3265 | post | 57 | char *found; |
58 | |||
59 | /* work-around for access() */ |
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60 | unsigned int try_access(const char *f) |
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61 | { |
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62 | int fd; |
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63 | |||
64 | fd = open(f, O_RDONLY); |
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3287 | post | 65 | if (fd > -1) { |
3265 | post | 66 | close(fd); |
3287 | post | 67 | return 0; |
3265 | post | 68 | } else |
3287 | post | 69 | return -1; |
3265 | post | 70 | } |
71 | |||
72 | /* Returns the full path of "cmd" if cmd is found, else just hand back |
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73 | * cmd as it was presented */ |
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74 | char *find_command(char *cmd) |
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75 | { |
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76 | char *path_orig, *path_tok; |
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77 | char *path[PATH_MAX]; |
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3287 | post | 78 | int n = 0, i = 0; |
3265 | post | 79 | size_t x = strlen(cmd) + 2; |
80 | |||
81 | found = (char *)malloc(PATH_MAX); |
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82 | |||
3287 | post | 83 | /* The user has specified a full or relative path, just give it back. */ |
84 | #ifdef HELENOS |
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85 | if (-1 != try_access(cmd)) |
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86 | #else |
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87 | if (-1 != access(cmd, F_OK)) |
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88 | #endif |
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89 | { |
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90 | return (char *) cmd; |
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91 | } |
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3265 | post | 92 | |
93 | #ifdef HELENOS |
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94 | path_orig = PATH; |
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95 | #else |
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96 | path_orig = getenv("PATH"); |
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97 | if (NULL == path_orig) |
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98 | path_orig = PATH; |
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99 | #endif |
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100 | |||
101 | path_tok = cli_strdup(path_orig); |
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102 | |||
103 | /* Extract the PATH env to a path[] array */ |
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104 | path[n] = cli_strtok(path_tok, PATH_DELIM); |
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105 | while (NULL != path[n]) { |
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106 | if ((strlen(path[n]) + x ) > PATH_MAX) { |
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107 | cli_error(CL_ENOTSUP, |
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108 | "Segment %d of path is too large, search ends at segment %d", |
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109 | n, n-1); |
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110 | break; |
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111 | } |
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112 | path[++n] = cli_strtok(NULL, PATH_DELIM); |
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113 | } |
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114 | |||
115 | /* We now have n places to look for the command */ |
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116 | for (i=0; path[i]; i++) { |
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117 | memset(found, 0, sizeof(found)); |
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118 | snprintf(found, PATH_MAX, "%s/%s", path[i], cmd); |
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119 | #ifdef HELENOS |
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3287 | post | 120 | if (-1 != try_access(found)) |
3265 | post | 121 | #else |
3287 | post | 122 | if (-1 != access(found, F_OK)) |
3265 | post | 123 | #endif |
3287 | post | 124 | { |
3265 | post | 125 | free(path_tok); |
126 | return (char *) found; |
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127 | } |
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128 | } |
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129 | |||
130 | /* We didn't find it, just give it back as-is. Could be an alias |
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131 | * set in the parent shell */ |
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132 | free(path_tok); |
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133 | return (char *) cmd; |
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134 | } |
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135 | |||
136 | #ifdef HELENOS |
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137 | task_id_t try_exec(char *cmd, char **argv) |
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138 | { |
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139 | task_id_t tid; |
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140 | char *tmp; |
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141 | |||
142 | tmp = cli_strdup(find_command(cmd)); |
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143 | free(found); |
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144 | |||
3298 | post | 145 | /* TODO: put the cwd in front of tmp if tmp[0] != root |
146 | * which fixes relative paths fed to task_spawn */ |
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147 | |||
3265 | post | 148 | tid = task_spawn((const char *)tmp, (const char **)argv); |
149 | free(tmp); |
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150 | |||
151 | if (tid == 0) |
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152 | /* HelenOS does not set errno, so all we can do is report |
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153 | * a task ID of 0 as a generic failure. */ |
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154 | cli_error(CL_EEXEC, "Can not spawn %s", cmd); |
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155 | |||
156 | return tid; |
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157 | } |
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158 | |||
159 | #else |
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160 | int try_exec(char *cmd, char **argv) |
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161 | { |
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162 | char *tmp; |
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163 | pid_t pid; |
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164 | int status; |
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165 | |||
166 | /* Copy the result of allocated 'found' */ |
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167 | tmp = cli_strdup(find_command(cmd)); |
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168 | /* free the pointer, no longer needed */ |
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169 | free(found); |
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170 | |||
171 | if (-1 == (access(tmp, F_OK))) { |
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172 | cli_error(CL_EFAIL, |
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173 | "%s : No such external, modular or builtin command", tmp); |
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174 | free(tmp); |
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175 | return CL_EFAIL; |
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176 | } |
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177 | |||
178 | /* Create a child to run the program */ |
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179 | pid = fork(); |
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180 | if (pid == 0) { |
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181 | execv(tmp, argv); |
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182 | exit(errno); |
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183 | } else if (pid > 0) { |
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184 | /* Block until we get a PID (and result) */ |
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185 | wait(&status); |
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186 | status = status / 256; |
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187 | } else { |
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188 | /* Could not fork, ulimit or out of memory */ |
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189 | cli_error(CL_ENOMEM, "Could not fork"); |
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190 | free(tmp); |
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191 | return CL_ENOMEM; |
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192 | } |
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193 | |||
194 | free(tmp); |
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195 | |||
196 | /* Decode any errors from execv() (these explain themselves) */ |
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197 | switch (status) { |
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198 | case ENOTDIR: |
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199 | cli_error(CL_EFAIL, "%s : No such file or directory", tmp); |
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200 | status = CL_EFAIL; |
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201 | break; |
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202 | case EISDIR: |
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203 | cli_error(CL_EFAIL, "%s : Command is a directory", tmp); |
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204 | status = CL_EFAIL; |
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205 | break; |
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206 | case EACCES: |
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207 | cli_error(CL_EPERM, "%s :", tmp); |
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208 | status = CL_EFAIL; |
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209 | break; |
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210 | case ENOMEM: |
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211 | cli_error(CL_ENOMEM, "%s :", tmp); |
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212 | status = CL_EFAIL; |
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213 | break; |
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214 | case ENAMETOOLONG: |
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215 | cli_error(CL_EFAIL, "Argument list too long"); |
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216 | status = CL_EFAIL; |
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217 | break; |
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218 | case EFAULT: |
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219 | cli_error(CL_EFAIL, "Invalid argument pointer\n(please report " |
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220 | "this to %s)", PACKAGE_BUGREPORT); |
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221 | status = CL_EFAIL; |
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222 | break; |
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223 | } |
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224 | |||
225 | return status; |
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226 | } |
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227 | |||
228 | #endif /* HELENOS */ |