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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 | |||
54 | /* Easiest way to handle a shared + allocated string, a structure with |
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55 | * one member is sort of silly :) */ |
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56 | char *found; |
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57 | |||
58 | /* work-around for access() */ |
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59 | unsigned int try_access(const char *f) |
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60 | { |
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61 | int fd; |
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62 | |||
63 | fd = open(f, O_RDONLY); |
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64 | if (fd > 0) { |
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65 | close(fd); |
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66 | return 1; |
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67 | } else |
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68 | return 0; |
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69 | } |
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70 | |||
71 | /* Returns the full path of "cmd" if cmd is found, else just hand back |
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72 | * cmd as it was presented */ |
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73 | char *find_command(char *cmd) |
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74 | { |
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75 | char *path_orig, *path_tok; |
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76 | char *path[PATH_MAX]; |
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77 | int rc, n = 0, i = 0; |
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78 | size_t x = strlen(cmd) + 2; |
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79 | |||
80 | found = (char *)malloc(PATH_MAX); |
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81 | |||
82 | /* The user has specified the full path, just give it back. Don't test it, |
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83 | * they seem to know what they're doing. */ |
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84 | if (cmd[0] == '/' || cmd [0] == '.') |
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85 | return (char *)cmd; |
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86 | |||
87 | #ifdef HELENOS |
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88 | path_orig = PATH; |
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89 | #else |
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90 | path_orig = getenv("PATH"); |
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91 | if (NULL == path_orig) |
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92 | path_orig = PATH; |
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93 | #endif |
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94 | |||
95 | path_tok = cli_strdup(path_orig); |
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96 | |||
97 | /* Extract the PATH env to a path[] array */ |
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98 | path[n] = cli_strtok(path_tok, PATH_DELIM); |
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99 | while (NULL != path[n]) { |
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100 | if ((strlen(path[n]) + x ) > PATH_MAX) { |
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101 | cli_error(CL_ENOTSUP, |
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102 | "Segment %d of path is too large, search ends at segment %d", |
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103 | n, n-1); |
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104 | break; |
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105 | } |
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106 | path[++n] = cli_strtok(NULL, PATH_DELIM); |
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107 | } |
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108 | |||
109 | /* We now have n places to look for the command */ |
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110 | for (i=0; path[i]; i++) { |
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111 | memset(found, 0, sizeof(found)); |
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112 | snprintf(found, PATH_MAX, "%s/%s", path[i], cmd); |
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113 | #ifdef HELENOS |
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114 | rc = try_access(found); |
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115 | #else |
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116 | rc = access(found, F_OK); |
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117 | #endif |
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118 | if (rc >= 0) { |
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119 | /* We found it */ |
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120 | free(path_tok); |
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121 | return (char *) found; |
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122 | } |
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123 | } |
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124 | |||
125 | /* We didn't find it, just give it back as-is. Could be an alias |
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126 | * set in the parent shell */ |
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127 | free(path_tok); |
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128 | return (char *) cmd; |
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129 | } |
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130 | |||
131 | #ifdef HELENOS |
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132 | task_id_t try_exec(char *cmd, char **argv) |
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133 | { |
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134 | task_id_t tid; |
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135 | char *tmp; |
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136 | |||
137 | tmp = cli_strdup(find_command(cmd)); |
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138 | free(found); |
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139 | |||
140 | tid = task_spawn((const char *)tmp, (const char **)argv); |
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141 | free(tmp); |
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142 | |||
143 | if (tid == 0) |
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144 | /* HelenOS does not set errno, so all we can do is report |
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145 | * a task ID of 0 as a generic failure. */ |
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146 | cli_error(CL_EEXEC, "Can not spawn %s", cmd); |
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147 | |||
148 | return tid; |
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149 | } |
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150 | |||
151 | #else |
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152 | int try_exec(char *cmd, char **argv) |
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153 | { |
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154 | char *tmp; |
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155 | pid_t pid; |
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156 | int status; |
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157 | |||
158 | /* Copy the result of allocated 'found' */ |
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159 | tmp = cli_strdup(find_command(cmd)); |
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160 | /* free the pointer, no longer needed */ |
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161 | free(found); |
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162 | |||
163 | if (-1 == (access(tmp, F_OK))) { |
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164 | cli_error(CL_EFAIL, |
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165 | "%s : No such external, modular or builtin command", tmp); |
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166 | free(tmp); |
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167 | return CL_EFAIL; |
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168 | } |
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169 | |||
170 | /* Create a child to run the program */ |
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171 | pid = fork(); |
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172 | if (pid == 0) { |
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173 | execv(tmp, argv); |
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174 | exit(errno); |
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175 | } else if (pid > 0) { |
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176 | /* Block until we get a PID (and result) */ |
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177 | wait(&status); |
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178 | status = status / 256; |
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179 | } else { |
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180 | /* Could not fork, ulimit or out of memory */ |
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181 | cli_error(CL_ENOMEM, "Could not fork"); |
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182 | free(tmp); |
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183 | return CL_ENOMEM; |
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184 | } |
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185 | |||
186 | free(tmp); |
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187 | |||
188 | /* No need to go any further if status == 0 */ |
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189 | /* |
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190 | if (status == 0) |
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191 | return status; |
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192 | */ |
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193 | /* Decode any errors from execv() (these explain themselves) */ |
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194 | switch (status) { |
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195 | case ENOTDIR: |
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196 | cli_error(CL_EFAIL, "%s : No such file or directory", tmp); |
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197 | status = CL_EFAIL; |
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198 | break; |
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199 | case EISDIR: |
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200 | cli_error(CL_EFAIL, "%s : Command is a directory", tmp); |
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201 | status = CL_EFAIL; |
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202 | break; |
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203 | case EACCES: |
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204 | cli_error(CL_EPERM, "%s :", tmp); |
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205 | status = CL_EFAIL; |
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206 | break; |
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207 | case ENOMEM: |
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208 | cli_error(CL_ENOMEM, "%s :", tmp); |
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209 | status = CL_EFAIL; |
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210 | break; |
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211 | case ENAMETOOLONG: |
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212 | cli_error(CL_EFAIL, "Argument list too long"); |
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213 | status = CL_EFAIL; |
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214 | break; |
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215 | case EFAULT: |
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216 | cli_error(CL_EFAIL, "Invalid argument pointer\n(please report " |
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217 | "this to %s)", PACKAGE_BUGREPORT); |
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218 | status = CL_EFAIL; |
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219 | break; |
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220 | } |
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221 | |||
222 | return status; |
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223 | } |
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224 | |||
225 | #endif /* HELENOS */ |