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45 | luk | 1 | |
2 | /// inotify cron table manipulator main file |
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3 | /** |
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4 | * \file ict-main.cpp |
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5 | * |
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6 | * inotify cron system |
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7 | * |
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8 | * Copyright (C) 2006 Lukas Jelinek, <lukas@aiken.cz> |
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9 | * |
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10 | * This program is free software; you can use it, redistribute |
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11 | * it and/or modify it under the terms of the GNU General Public |
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12 | * License, version 2 (see LICENSE-GPL). |
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13 | * |
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14 | */ |
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15 | |||
16 | |||
17 | #include <argp.h> |
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18 | #include <pwd.h> |
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19 | #include <string> |
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20 | #include <stdio.h> |
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21 | #include <unistd.h> |
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22 | #include <sys/stat.h> |
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23 | #include <sys/wait.h> |
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24 | |||
25 | #include "incrontab.h" |
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26 | |||
27 | |||
28 | // #define INCRON_DEFAULT_EDITOR "nano" // for vim haters like me ;-) |
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29 | #define INCRON_DEFAULT_EDITOR "vim" |
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30 | |||
31 | |||
32 | const char* argp_program_version = "incrontab 0.1.0"; |
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33 | const char* argp_program_bug_address = "<bugs@aiken.cz>"; |
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34 | |||
35 | static char doc[] = "Table manipulator for incrond (inotify Cron daemon)"; |
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36 | |||
37 | static char args_doc[] = "FILE"; |
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38 | |||
39 | static struct argp_option options[] = { |
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40 | {"list", 'l', 0, 0, "List current table" }, |
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41 | {"remove", 'r', 0, 0, "Remove table completely" }, |
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42 | {"edit", 'e', 0, 0, "Edit table" }, |
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43 | {"user", 'u', "USER", 0, "Override current user" }, |
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44 | { 0 } |
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45 | }; |
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46 | |||
47 | enum |
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48 | { |
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49 | OPER_NONE, |
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50 | OPER_LIST, |
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51 | OPER_REMOVE, |
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52 | OPER_EDIT |
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53 | }; |
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54 | |||
55 | struct arguments |
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56 | { |
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57 | char *user; |
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58 | int oper; |
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59 | char *file; |
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60 | }; |
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61 | |||
62 | static error_t parse_opt (int key, char *arg, struct argp_state *state) |
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63 | { |
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64 | struct arguments* arguments = (struct arguments*) state->input; |
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65 | |||
66 | switch (key) { |
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67 | case 'l': |
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68 | arguments->oper = OPER_LIST; |
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69 | break; |
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70 | case 'r': |
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71 | arguments->oper = OPER_REMOVE; |
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72 | break; |
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73 | case 'e': |
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74 | arguments->oper = OPER_EDIT; |
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75 | break; |
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76 | case 'u': |
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77 | arguments->user = arg; |
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78 | break; |
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79 | case ARGP_KEY_ARG: |
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80 | if (state->arg_num >= 1) |
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81 | argp_usage(state); |
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82 | arguments->file = arg; |
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83 | break; |
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84 | case ARGP_KEY_END: |
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85 | break; |
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86 | default: |
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87 | return ARGP_ERR_UNKNOWN; |
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88 | } |
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89 | |||
90 | return 0; |
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91 | } |
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92 | |||
93 | |||
94 | static struct argp argp = { options, parse_opt, args_doc, doc }; |
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95 | |||
96 | void unlink_suid(const char* file, uid_t uid) |
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97 | { |
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98 | uid_t iu = geteuid(); |
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99 | seteuid(uid); |
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100 | unlink(file); |
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101 | seteuid(iu); |
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102 | } |
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103 | |||
104 | bool copy_from_file(const char* path, const char* user) |
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105 | { |
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106 | InCronTab tab; |
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107 | std::string s(path); |
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108 | if (s == "-") |
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109 | s = "/dev/stdin"; |
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110 | if (!tab.Load(s)) { |
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111 | fprintf(stderr, "cannot load table from file: %s\n", path); |
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112 | return false; |
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113 | } |
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114 | |||
115 | std::string out(InCronTab::GetUserTablePath(user)); |
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116 | if (!tab.Save(out)) { |
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117 | fprintf(stderr, "cannot create table for user: %s\n", user); |
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118 | return false; |
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119 | } |
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120 | |||
121 | return true; |
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122 | } |
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123 | |||
124 | bool remove_table(const char* user) |
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125 | { |
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126 | std::string tp(InCronTab::GetUserTablePath(user)); |
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127 | |||
128 | if (unlink(tp.c_str()) != 0 && errno != ENOENT) { |
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129 | fprintf(stderr, "cannot remove table for user: %s\n", user); |
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130 | return false; |
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131 | } |
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132 | |||
133 | return true; |
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134 | } |
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135 | |||
136 | bool list_table(const char* user) |
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137 | { |
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138 | std::string tp(InCronTab::GetUserTablePath(user)); |
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139 | |||
140 | if (access(tp.c_str(), R_OK) != 0) { |
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141 | if (errno == ENOENT) { |
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142 | fprintf(stderr, "no table for %s\n", user); |
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143 | return true; |
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144 | } |
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145 | else { |
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146 | fprintf(stderr, "cannot read table for %s: %s\n", user, strerror(errno)); |
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147 | return false; |
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148 | } |
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149 | } |
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150 | |||
151 | std::string cmd("cat "); |
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152 | cmd.append(tp); |
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153 | return system(cmd.c_str()) == 0; |
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154 | } |
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155 | |||
156 | bool edit_table(const char* user) |
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157 | { |
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158 | std::string tp(InCronTab::GetUserTablePath(user)); |
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159 | |||
160 | struct passwd* ppwd = getpwnam(user); |
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161 | if (ppwd == NULL) { |
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162 | fprintf(stderr, "cannot find user %s: %s\n", user, strerror(errno)); |
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163 | return false; |
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164 | } |
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165 | uid_t uid = ppwd->pw_uid; |
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166 | |||
167 | char s[NAME_MAX]; |
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168 | strcpy(s, "/tmp/incron.table-XXXXXX"); |
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169 | |||
170 | uid_t iu = geteuid(); |
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171 | |||
172 | if (seteuid(uid) != 0) { |
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173 | fprintf(stderr, "cannot change effective UID: %s\n", strerror(errno)); |
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174 | return false; |
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175 | } |
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176 | |||
177 | int fd = mkstemp(s); |
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178 | if (fd == -1) { |
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179 | fprintf(stderr, "cannot create temporary file: %s\n", strerror(errno)); |
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180 | return false; |
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181 | } |
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182 | |||
183 | if (fchmod(fd, 0644) != 0) { |
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184 | fprintf(stderr, "cannot change mode of temporary file: %s\n", strerror(errno)); |
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185 | close(fd); |
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186 | unlink_suid(s, uid); |
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187 | return false; |
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188 | } |
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189 | |||
190 | if (seteuid(iu) != 0) { |
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191 | fprintf(stderr, "cannot change effective UID: %s\n", strerror(errno)); |
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192 | close(fd); |
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193 | unlink_suid(s, uid); |
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194 | return false; |
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195 | } |
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196 | |||
197 | FILE* out = fdopen(fd, "w"); |
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198 | if (out == NULL) { |
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199 | fprintf(stderr, "cannot write to temporary file: %s\n", strerror(errno)); |
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200 | close(fd); |
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201 | unlink_suid(s, uid); |
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202 | return false; |
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203 | } |
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204 | |||
205 | FILE* in = fopen(tp.c_str(), "r"); |
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206 | if (in == NULL) { |
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207 | if (errno == ENOENT) { |
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208 | in = fopen("/dev/null", "r"); |
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209 | if (in == NULL) { |
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210 | fprintf(stderr, "cannot get empty table for %s: %s\n", user, strerror(errno)); |
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211 | fclose(out); |
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212 | unlink_suid(s, uid); |
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213 | return false; |
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214 | } |
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215 | } |
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216 | else { |
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217 | fprintf(stderr, "cannot read old table for %s: %s\n", user, strerror(errno)); |
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218 | fclose(out); |
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219 | unlink_suid(s, uid); |
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220 | return false; |
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221 | } |
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222 | } |
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223 | |||
224 | char buf[1024]; |
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225 | while (fgets(buf, 1024, in) != NULL) { |
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226 | fputs(buf, out); |
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227 | } |
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228 | fclose(in); |
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229 | fclose(out); |
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230 | |||
231 | struct stat st; |
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232 | if (stat(s, &st) != 0) { |
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233 | fprintf(stderr, "cannot stat temporary file: %s\n", strerror(errno)); |
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234 | unlink_suid(s, uid); |
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235 | return false; |
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236 | } |
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237 | |||
238 | time_t mt = st.st_mtime; |
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239 | |||
240 | const char* e = getenv("EDITOR"); |
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241 | if (e == NULL) |
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242 | e = INCRON_DEFAULT_EDITOR; |
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243 | |||
244 | pid_t pid = fork(); |
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245 | if (pid == 0) { |
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246 | if (setuid(uid) != 0) { |
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247 | fprintf(stderr, "cannot set user %s: %s\n", user, strerror(errno)); |
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248 | return false; |
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249 | } |
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250 | |||
251 | execlp(e, e, s, NULL); |
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252 | _exit(1); |
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253 | } |
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254 | else if (pid > 0) { |
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255 | int status; |
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256 | if (wait(&status) != pid) { |
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257 | perror("error while waiting for editor"); |
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258 | unlink_suid(s, uid); |
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259 | return false; |
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260 | } |
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261 | if (!(WIFEXITED(status)) || WEXITSTATUS(status) != 0) { |
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262 | perror("editor finished with error"); |
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263 | unlink_suid(s, uid); |
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264 | return false; |
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265 | } |
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266 | } |
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267 | else { |
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268 | perror("cannot start editor"); |
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269 | unlink_suid(s, uid); |
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270 | return false; |
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271 | } |
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272 | |||
273 | if (stat(s, &st) != 0) { |
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274 | fprintf(stderr, "cannot stat temporary file: %s\n", strerror(errno)); |
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275 | unlink_suid(s, uid); |
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276 | return false; |
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277 | } |
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278 | |||
279 | if (st.st_mtime == mt) { |
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280 | fprintf(stderr, "table unchanged\n"); |
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281 | unlink_suid(s, uid); |
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282 | return true; |
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283 | } |
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284 | |||
285 | InCronTab ict; |
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286 | if (!ict.Load(s) || !ict.Save(tp)) { |
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287 | fprintf(stderr, "cannot move temporary table: %s\n", strerror(errno)); |
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288 | unlink(s); |
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289 | return false; |
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290 | } |
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291 | |||
292 | fprintf(stderr, "table updated\n"); |
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293 | |||
294 | unlink_suid(s, uid); |
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295 | return true; |
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296 | } |
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297 | |||
298 | |||
299 | int main(int argc, char** argv) |
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300 | { |
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301 | struct arguments arguments; |
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302 | |||
303 | arguments.user = NULL; |
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304 | arguments.oper = OPER_NONE; |
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305 | arguments.file = NULL; |
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306 | |||
307 | argp_parse (&argp, argc, argv, 0, 0, &arguments); |
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308 | |||
309 | if (arguments.file != NULL && arguments.oper != OPER_NONE) { |
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310 | fprintf(stderr, "invalid arguments - specify source file or operation\n"); |
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311 | return 1; |
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312 | } |
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313 | if (arguments.file == NULL && arguments.oper == OPER_NONE) { |
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314 | fprintf(stderr, "invalid arguments - specify source file or operation\n"); |
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315 | return 1; |
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316 | } |
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317 | |||
318 | uid_t uid = getuid(); |
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319 | |||
320 | if (uid != 0 && arguments.user != NULL) { |
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321 | fprintf(stderr, "cannot access table for user %s: permission denied\n", arguments.user); |
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322 | return 1; |
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323 | } |
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324 | |||
325 | struct passwd pwd; |
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326 | |||
327 | if (arguments.user == NULL) { |
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328 | struct passwd* ppwd = getpwuid(uid); |
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329 | if (ppwd == NULL) { |
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330 | fprintf(stderr, "cannot determine current user\n"); |
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331 | return 1; |
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332 | } |
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333 | memcpy(&pwd, ppwd, sizeof(pwd)); |
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334 | arguments.user = pwd.pw_name; |
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335 | } |
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336 | else if (getpwnam(arguments.user) == NULL) { |
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337 | fprintf(stderr, "user %s not found\n", arguments.user); |
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338 | return 1; |
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339 | } |
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340 | |||
341 | if (!InCronTab::CheckUser(arguments.user)) { |
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342 | fprintf(stderr, "user %s is not allowed to use incron\n", arguments.user); |
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343 | return 1; |
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344 | } |
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345 | |||
346 | switch (arguments.oper) { |
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347 | case OPER_NONE: |
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348 | fprintf(stderr, "copying table from file: %s\n", arguments.file); |
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349 | if (!copy_from_file(arguments.file, arguments.user)) |
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350 | return 1; |
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351 | break; |
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352 | case OPER_LIST: |
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353 | if (!list_table(arguments.user)) |
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354 | return 1; |
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355 | break; |
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356 | case OPER_REMOVE: |
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357 | fprintf(stderr, "removing table for user %s\n", arguments.user); |
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358 | if (!remove_table(arguments.user)) |
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359 | return 1; |
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360 | break; |
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361 | case OPER_EDIT: |
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362 | if (!edit_table(arguments.user)) |
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363 | return 1; |
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364 | break; |
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365 | default: |
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366 | fprintf(stderr, "invalid usage\n"); |
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367 | return 1; |
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368 | } |
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369 | |||
370 | return 0; |
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371 | } |