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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 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 | } |