| 1 | /* Serial interface for a pipe to a separate program |
| 2 | Copyright (C) 1999-2017 Free Software Foundation, Inc. |
| 3 | |
| 4 | Contributed by Cygnus Solutions. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "serial.h" |
| 23 | #include "ser-base.h" |
| 24 | #include "ser-unix.h" |
| 25 | |
| 26 | #include "gdb_vfork.h" |
| 27 | |
| 28 | #include <sys/types.h> |
| 29 | #include <sys/socket.h> |
| 30 | #include "gdb_sys_time.h" |
| 31 | #include <fcntl.h> |
| 32 | #include "filestuff.h" |
| 33 | |
| 34 | #include <signal.h> |
| 35 | |
| 36 | static int pipe_open (struct serial *scb, const char *name); |
| 37 | static void pipe_close (struct serial *scb); |
| 38 | |
| 39 | struct pipe_state |
| 40 | { |
| 41 | int pid; |
| 42 | }; |
| 43 | |
| 44 | /* Open up a raw pipe. */ |
| 45 | |
| 46 | static int |
| 47 | pipe_open (struct serial *scb, const char *name) |
| 48 | { |
| 49 | #if !HAVE_SOCKETPAIR |
| 50 | return -1; |
| 51 | #else |
| 52 | struct pipe_state *state; |
| 53 | /* This chunk: */ |
| 54 | /* Copyright (c) 1988, 1993 |
| 55 | * The Regents of the University of California. All rights reserved. |
| 56 | * |
| 57 | * This code is derived from software written by Ken Arnold and |
| 58 | * published in UNIX Review, Vol. 6, No. 8. |
| 59 | */ |
| 60 | int pdes[2]; |
| 61 | int err_pdes[2]; |
| 62 | int pid; |
| 63 | |
| 64 | if (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, pdes) < 0) |
| 65 | return -1; |
| 66 | if (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0) |
| 67 | { |
| 68 | close (pdes[0]); |
| 69 | close (pdes[1]); |
| 70 | return -1; |
| 71 | } |
| 72 | |
| 73 | /* Create the child process to run the command in. Note that the |
| 74 | apparent call to vfork() below *might* actually be a call to |
| 75 | fork() due to the fact that autoconf will ``#define vfork fork'' |
| 76 | on certain platforms. */ |
| 77 | pid = vfork (); |
| 78 | |
| 79 | /* Error. */ |
| 80 | if (pid == -1) |
| 81 | { |
| 82 | close (pdes[0]); |
| 83 | close (pdes[1]); |
| 84 | close (err_pdes[0]); |
| 85 | close (err_pdes[1]); |
| 86 | return -1; |
| 87 | } |
| 88 | |
| 89 | if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1) |
| 90 | { |
| 91 | close (err_pdes[0]); |
| 92 | close (err_pdes[1]); |
| 93 | err_pdes[0] = err_pdes[1] = -1; |
| 94 | } |
| 95 | |
| 96 | /* Child. */ |
| 97 | if (pid == 0) |
| 98 | { |
| 99 | /* We don't want ^c to kill the connection. */ |
| 100 | #ifdef HAVE_SETSID |
| 101 | pid_t sid = setsid (); |
| 102 | if (sid == -1) |
| 103 | signal (SIGINT, SIG_IGN); |
| 104 | #else |
| 105 | signal (SIGINT, SIG_IGN); |
| 106 | #endif |
| 107 | |
| 108 | /* Re-wire pdes[1] to stdin/stdout. */ |
| 109 | close (pdes[0]); |
| 110 | if (pdes[1] != STDOUT_FILENO) |
| 111 | { |
| 112 | dup2 (pdes[1], STDOUT_FILENO); |
| 113 | close (pdes[1]); |
| 114 | } |
| 115 | dup2 (STDOUT_FILENO, STDIN_FILENO); |
| 116 | |
| 117 | if (err_pdes[0] != -1) |
| 118 | { |
| 119 | close (err_pdes[0]); |
| 120 | dup2 (err_pdes[1], STDERR_FILENO); |
| 121 | close (err_pdes[1]); |
| 122 | } |
| 123 | |
| 124 | close_most_fds (); |
| 125 | execl ("/bin/sh", "sh", "-c", name, (char *) 0); |
| 126 | _exit (127); |
| 127 | } |
| 128 | |
| 129 | /* Parent. */ |
| 130 | close (pdes[1]); |
| 131 | if (err_pdes[1] != -1) |
| 132 | close (err_pdes[1]); |
| 133 | /* :end chunk */ |
| 134 | state = XNEW (struct pipe_state); |
| 135 | state->pid = pid; |
| 136 | scb->fd = pdes[0]; |
| 137 | scb->error_fd = err_pdes[0]; |
| 138 | scb->state = state; |
| 139 | |
| 140 | /* If we don't do this, GDB simply exits when the remote side dies. */ |
| 141 | signal (SIGPIPE, SIG_IGN); |
| 142 | return 0; |
| 143 | #endif |
| 144 | } |
| 145 | |
| 146 | static void |
| 147 | pipe_close (struct serial *scb) |
| 148 | { |
| 149 | struct pipe_state *state = (struct pipe_state *) scb->state; |
| 150 | |
| 151 | close (scb->fd); |
| 152 | scb->fd = -1; |
| 153 | |
| 154 | if (state != NULL) |
| 155 | { |
| 156 | int wait_result, status; |
| 157 | |
| 158 | /* Don't kill the task right away, give it a chance to shut down cleanly. |
| 159 | But don't wait forever though. */ |
| 160 | #define PIPE_CLOSE_TIMEOUT 5 |
| 161 | |
| 162 | /* Assume the program will exit after SIGTERM. Might be |
| 163 | useful to print any remaining stderr output from |
| 164 | scb->error_fd while waiting. */ |
| 165 | #define SIGTERM_TIMEOUT INT_MAX |
| 166 | |
| 167 | wait_result = -1; |
| 168 | #ifdef HAVE_WAITPID |
| 169 | wait_result = wait_to_die_with_timeout (state->pid, &status, |
| 170 | PIPE_CLOSE_TIMEOUT); |
| 171 | #endif |
| 172 | if (wait_result == -1) |
| 173 | { |
| 174 | kill (state->pid, SIGTERM); |
| 175 | #ifdef HAVE_WAITPID |
| 176 | wait_to_die_with_timeout (state->pid, &status, SIGTERM_TIMEOUT); |
| 177 | #endif |
| 178 | } |
| 179 | |
| 180 | if (scb->error_fd != -1) |
| 181 | close (scb->error_fd); |
| 182 | scb->error_fd = -1; |
| 183 | xfree (state); |
| 184 | scb->state = NULL; |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | int |
| 189 | gdb_pipe (int pdes[2]) |
| 190 | { |
| 191 | #if !HAVE_SOCKETPAIR |
| 192 | errno = ENOSYS; |
| 193 | return -1; |
| 194 | #else |
| 195 | |
| 196 | if (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, pdes) < 0) |
| 197 | return -1; |
| 198 | |
| 199 | /* If we don't do this, GDB simply exits when the remote side |
| 200 | dies. */ |
| 201 | signal (SIGPIPE, SIG_IGN); |
| 202 | return 0; |
| 203 | #endif |
| 204 | } |
| 205 | |
| 206 | static const struct serial_ops pipe_ops = |
| 207 | { |
| 208 | "pipe", |
| 209 | pipe_open, |
| 210 | pipe_close, |
| 211 | NULL, |
| 212 | ser_base_readchar, |
| 213 | ser_base_write, |
| 214 | ser_base_flush_output, |
| 215 | ser_base_flush_input, |
| 216 | ser_base_send_break, |
| 217 | ser_base_raw, |
| 218 | ser_base_get_tty_state, |
| 219 | ser_base_copy_tty_state, |
| 220 | ser_base_set_tty_state, |
| 221 | ser_base_print_tty_state, |
| 222 | ser_base_noflush_set_tty_state, |
| 223 | ser_base_setbaudrate, |
| 224 | ser_base_setstopbits, |
| 225 | ser_base_setparity, |
| 226 | ser_base_drain_output, |
| 227 | ser_base_async, |
| 228 | ser_unix_read_prim, |
| 229 | ser_unix_write_prim |
| 230 | }; |
| 231 | |
| 232 | void |
| 233 | _initialize_ser_pipe (void) |
| 234 | { |
| 235 | serial_add_interface (&pipe_ops); |
| 236 | } |