| 1 | /* Subprocesses with pipes. |
| 2 | |
| 3 | Copyright (C) 2005-2012 Free Software Foundation, Inc. |
| 4 | |
| 5 | This program is free software: you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation, either version 3 of the License, or |
| 8 | (at your option) any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | /* Written by Juan Manuel Guerrero <juan.guerrero@gmx.de>. */ |
| 19 | |
| 20 | |
| 21 | #include <config.h> |
| 22 | |
| 23 | #include "subpipe.h" |
| 24 | |
| 25 | #include <errno.h> |
| 26 | #include <fcntl.h> |
| 27 | #include <sys/stat.h> |
| 28 | #include <process.h> |
| 29 | #include <signal.h> |
| 30 | #include <stdio.h> |
| 31 | #include <stdlib.h> |
| 32 | #include <string.h> |
| 33 | #include <unistd.h> |
| 34 | #include "xalloc.h" |
| 35 | |
| 36 | |
| 37 | #ifndef STDIN_FILENO |
| 38 | # define STDIN_FILENO 0 |
| 39 | #endif |
| 40 | #ifndef STDOUT_FILENO |
| 41 | # define STDOUT_FILENO 1 |
| 42 | #endif |
| 43 | |
| 44 | |
| 45 | #include "error.h" |
| 46 | |
| 47 | #include "gettext.h" |
| 48 | #define _(Msgid) gettext (Msgid) |
| 49 | |
| 50 | |
| 51 | /* Initialize this module. */ |
| 52 | |
| 53 | |
| 54 | static int old_stdin; |
| 55 | static int old_stdout; |
| 56 | static char **arguments; |
| 57 | static char tmp_file_name[2][L_tmpnam]; |
| 58 | |
| 59 | #define remove_tmp_file(fd, name) \ |
| 60 | do { \ |
| 61 | close ((fd)); \ |
| 62 | if (unlink ((name))) \ |
| 63 | error (EXIT_FAILURE, 0, _("removing of '%s' failed"), (name)); \ |
| 64 | } while (0) |
| 65 | |
| 66 | |
| 67 | void |
| 68 | init_subpipe(void) |
| 69 | { |
| 70 | char *tmpdir; |
| 71 | int fd; |
| 72 | |
| 73 | tmpdir = getenv("TMPDIR"); |
| 74 | if (tmpdir == NULL) |
| 75 | tmpdir = getenv("TMP"); |
| 76 | if (tmpdir == NULL) |
| 77 | tmpdir = getenv("TEMP"); |
| 78 | if (access(tmpdir, D_OK)) |
| 79 | tmpdir = "."; |
| 80 | |
| 81 | strcpy(tmp_file_name[0], tmpdir); |
| 82 | strcat(tmp_file_name[0], "/bnXXXXXX"); |
| 83 | fd = mkstemp(tmp_file_name[0]); |
| 84 | if (fd < 0) |
| 85 | error(EXIT_FAILURE, 0, _("creation of a temporary file failed")); |
| 86 | close (fd); |
| 87 | |
| 88 | strcpy(tmp_file_name[1], tmpdir); |
| 89 | strcat(tmp_file_name[1], "/bnXXXXXX"); |
| 90 | fd = mkstemp(tmp_file_name[1]); |
| 91 | if (fd < 0) |
| 92 | error(EXIT_FAILURE, 0, _("creation of a temporary file failed")); |
| 93 | close (fd); |
| 94 | } |
| 95 | |
| 96 | |
| 97 | /* Create a subprocess that is run as a filter. ARGV is the |
| 98 | NULL-terminated argument vector for the subprocess. Store read and |
| 99 | write file descriptors for communication with the subprocess into |
| 100 | FD[0] and FD[1]: input meant for the process can be written into |
| 101 | FD[0], and output from the process can be read from FD[1]. Return |
| 102 | the subprocess id. |
| 103 | |
| 104 | Because DOS has neither fork nor pipe functionality to run the subprocess |
| 105 | as a filter, the filter is reproduced using temporary files. First bison's |
| 106 | stdout is redirected to a temporary file. After bison has produced all of |
| 107 | is output, this file is closed and connected to m4's stdin. All m4's output |
| 108 | is redirected from m4's stdout to a second temporary file and reopened as |
| 109 | bison's stdin. */ |
| 110 | |
| 111 | pid_t |
| 112 | create_subpipe(char const *const *argv, int fd[2]) |
| 113 | { |
| 114 | int argc; |
| 115 | int from_in_fd; /* pipe from bison to m4. */ |
| 116 | pid_t pid; |
| 117 | |
| 118 | |
| 119 | pid = getpid(); |
| 120 | |
| 121 | /* |
| 122 | * Save original stdin and stdout |
| 123 | * for later restauration. |
| 124 | */ |
| 125 | old_stdin = dup(STDIN_FILENO); |
| 126 | if (old_stdin < 0) |
| 127 | error(EXIT_FAILURE, 0, _("saving stdin failed")); |
| 128 | |
| 129 | old_stdout = dup(STDOUT_FILENO); |
| 130 | if (old_stdout < 0) |
| 131 | error(EXIT_FAILURE, 0, _("saving stdout failed")); |
| 132 | |
| 133 | /* |
| 134 | * Save argv for later use. |
| 135 | */ |
| 136 | for (argc = 0; argv[argc]; argc++) |
| 137 | ; |
| 138 | argc++; |
| 139 | arguments = xmalloc(argc * sizeof(arguments[0])); |
| 140 | for (argc = 0; argv[argc]; argc++) |
| 141 | { |
| 142 | arguments[argc] = xmalloc((strlen(argv[argc]) + 1) * sizeof(arguments[0][0])); |
| 143 | strcpy(arguments[argc], argv[argc]); |
| 144 | } |
| 145 | arguments[argc] = NULL; |
| 146 | |
| 147 | /* |
| 148 | * All bison's output will be gathered in this temporary file |
| 149 | * and will be redirected to m4's stdin. |
| 150 | */ |
| 151 | from_in_fd = open(tmp_file_name[0], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR); |
| 152 | if (from_in_fd < 0) |
| 153 | error(EXIT_FAILURE, 0, _("opening of tmpfile failed")); |
| 154 | if (dup2(from_in_fd, STDOUT_FILENO) < 0) |
| 155 | { |
| 156 | remove_tmp_file(from_in_fd, tmp_file_name[0]); |
| 157 | error(EXIT_FAILURE, 0, _("redirecting bison's stdout to the temporary file failed")); |
| 158 | } |
| 159 | close(from_in_fd); |
| 160 | |
| 161 | |
| 162 | fd[0] = STDOUT_FILENO; |
| 163 | return pid; |
| 164 | } |
| 165 | |
| 166 | |
| 167 | /* A signal handler that just records that a signal has happened. */ |
| 168 | static int child_interrupted; |
| 169 | |
| 170 | static void |
| 171 | signal_catcher(int signo) |
| 172 | { |
| 173 | child_interrupted++; |
| 174 | } |
| 175 | |
| 176 | |
| 177 | void |
| 178 | end_of_output_subpipe(pid_t pid, int fd[2]) |
| 179 | { |
| 180 | char *program; |
| 181 | int from_out_fd = open(tmp_file_name[0], O_RDONLY, S_IRUSR); /* pipe from bison to m4. */ |
| 182 | int to_in_fd = open(tmp_file_name[1], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR); /* pipe from m4 to bison. */ |
| 183 | int status; |
| 184 | void (*previous_handler)(int); |
| 185 | |
| 186 | |
| 187 | program = strrchr(arguments[0], '/'); |
| 188 | if (program) |
| 189 | program++; |
| 190 | else |
| 191 | program = arguments[0]; |
| 192 | |
| 193 | /* |
| 194 | * Redirect bison's output to m4's stdin. |
| 195 | */ |
| 196 | if (from_out_fd < 0) |
| 197 | error(EXIT_FAILURE, 0, _("opening of tmpfile failed")); |
| 198 | if (dup2(from_out_fd, STDIN_FILENO) < 0) |
| 199 | { |
| 200 | remove_tmp_file(from_out_fd, tmp_file_name[0]); |
| 201 | error(EXIT_FAILURE, 0, _("redirecting m4's stdin from the temporary file failed")); |
| 202 | } |
| 203 | close(from_out_fd); |
| 204 | |
| 205 | /* |
| 206 | * All m4's output will be gathered in this temporary file |
| 207 | * and will be redirected to bison's stdin. |
| 208 | */ |
| 209 | if (to_in_fd < 0) |
| 210 | { |
| 211 | remove_tmp_file(STDIN_FILENO, tmp_file_name[0]); |
| 212 | error(EXIT_FAILURE, 0, _("opening of a temporary file failed")); |
| 213 | } |
| 214 | if (dup2(to_in_fd, STDOUT_FILENO) < 0) |
| 215 | { |
| 216 | remove_tmp_file(STDIN_FILENO, tmp_file_name[0]); |
| 217 | remove_tmp_file(to_in_fd, tmp_file_name[1]); |
| 218 | error(EXIT_FAILURE, 0, _("redirecting m4's stdout to a temporary file failed")); |
| 219 | } |
| 220 | close(to_in_fd); |
| 221 | |
| 222 | /* |
| 223 | * Run m4. |
| 224 | */ |
| 225 | child_interrupted = 0; |
| 226 | errno = 0; |
| 227 | previous_handler = signal(SIGINT, signal_catcher); |
| 228 | status = spawnvp(P_WAIT, program, arguments); |
| 229 | signal(SIGINT, previous_handler); |
| 230 | if (child_interrupted) |
| 231 | { |
| 232 | remove_tmp_file(STDIN_FILENO, tmp_file_name[0]); |
| 233 | remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]); |
| 234 | error(EXIT_FAILURE, 0, _("subsidiary program '%s' interrupted"), program); |
| 235 | } |
| 236 | if (status) |
| 237 | { |
| 238 | remove_tmp_file(STDIN_FILENO, tmp_file_name[0]); |
| 239 | remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]); |
| 240 | error(EXIT_FAILURE, 0, _(errno == ENOENT |
| 241 | ? "subsidiary program '%s' not found" |
| 242 | : status < 1 |
| 243 | ? "subsidiary program '%s' failed" |
| 244 | : "subsidiary program '%s' failed (status=%i, errno=%i)"), program, status, errno); |
| 245 | } |
| 246 | |
| 247 | |
| 248 | /* |
| 249 | * Redirect m4's output to bison's stdin. |
| 250 | */ |
| 251 | if (dup2(old_stdout, STDOUT_FILENO) < 0) |
| 252 | error(EXIT_FAILURE, 0, "restore of bison's stdout failed"); |
| 253 | close(old_stdout); |
| 254 | to_in_fd = open(tmp_file_name[1], O_RDONLY, S_IRUSR); /* pipe from m4 to bison. */ |
| 255 | if (to_in_fd < 0) |
| 256 | { |
| 257 | remove_tmp_file(STDIN_FILENO, tmp_file_name[0]); |
| 258 | error(EXIT_FAILURE, 0, _("opening of tmpfile failed")); |
| 259 | } |
| 260 | if (dup2(to_in_fd, STDIN_FILENO) < 0) |
| 261 | { |
| 262 | remove_tmp_file(STDIN_FILENO, tmp_file_name[0]); |
| 263 | remove_tmp_file(to_in_fd, tmp_file_name[1]); |
| 264 | error(EXIT_FAILURE, -1, "dup2"); |
| 265 | error(EXIT_FAILURE, 0, _("redirecting bison's stdin from the temporary file failed")); |
| 266 | } |
| 267 | close(to_in_fd); |
| 268 | |
| 269 | |
| 270 | fd[1] = STDIN_FILENO; |
| 271 | } |
| 272 | |
| 273 | |
| 274 | /* Free resources, unlink temporary files and restore stdin and stdout. */ |
| 275 | |
| 276 | void |
| 277 | reap_subpipe(pid_t pid, char const *program) |
| 278 | { |
| 279 | int argc; |
| 280 | |
| 281 | for (argc = 0; arguments[argc]; argc++) |
| 282 | free(arguments[argc]); |
| 283 | free(arguments); |
| 284 | |
| 285 | if (unlink(tmp_file_name[0])) |
| 286 | error(EXIT_FAILURE, 0, _("removing of '%s' failed"), tmp_file_name[0]); |
| 287 | if (unlink(tmp_file_name[1])) |
| 288 | error(EXIT_FAILURE, 0, _("removing of '%s' failed"), tmp_file_name[1]); |
| 289 | |
| 290 | if (dup2(old_stdin, STDIN_FILENO) < 0) |
| 291 | error(EXIT_FAILURE, 0, "restore of bison's stdin failed"); |
| 292 | close(old_stdin); |
| 293 | } |