mirror of https://github.com/martanne/abduco
580 lines
15 KiB
C
580 lines
15 KiB
C
/*
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* Copyright (c) 2013-2015 Marc André Tanner <mat at brain-dump.org>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <signal.h>
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#include <libgen.h>
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#include <string.h>
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#include <limits.h>
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#include <dirent.h>
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#include <termios.h>
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#include <time.h>
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#include <unistd.h>
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#include <sys/select.h>
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#include <sys/stat.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#if defined(__linux__) || defined(__CYGWIN__)
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# include <pty.h>
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#elif defined(__FreeBSD__) || defined(__DragonFly__)
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# include <libutil.h>
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#elif defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
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# include <util.h>
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#endif
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#if defined CTRL && defined _AIX
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#undef CTRL
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#endif
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#ifndef CTRL
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#define CTRL(k) ((k) & 0x1F)
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#endif
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#include "config.h"
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#if defined(_AIX)
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# include "forkpty-aix.c"
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#elif defined(__sun)
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# include "forkpty-sunos.c"
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#endif
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#define countof(arr) (sizeof(arr) / sizeof((arr)[0]))
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enum PacketType {
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MSG_CONTENT = 0,
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MSG_ATTACH = 1,
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MSG_DETACH = 2,
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MSG_RESIZE = 3,
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MSG_REDRAW = 4,
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MSG_EXIT = 5,
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};
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typedef struct {
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unsigned int type;
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size_t len;
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union {
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char msg[BUFSIZ];
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struct winsize ws;
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int i;
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bool b;
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} u;
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} Packet;
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typedef struct Client Client;
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struct Client {
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int socket;
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enum {
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STATE_CONNECTED,
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STATE_ATTACHED,
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STATE_DETACHED,
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STATE_DISCONNECTED,
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} state;
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bool need_resize;
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bool readonly;
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Client *next;
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};
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typedef struct {
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Client *clients;
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int socket;
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Packet pty_output;
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int pty;
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int exit_status;
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struct termios term;
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struct winsize winsize;
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pid_t pid;
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volatile sig_atomic_t running;
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const char *name;
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const char *session_name;
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char host[255];
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bool read_pty;
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} Server;
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static Server server = { .running = true, .exit_status = -1, .host = "@localhost" };
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static Client client;
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static struct termios orig_term, cur_term;
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static bool has_term, alternate_buffer;
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static struct sockaddr_un sockaddr = {
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.sun_family = AF_UNIX,
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};
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static bool set_socket_name(struct sockaddr_un *sockaddr, const char *name);
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static void die(const char *s);
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static void info(const char *str, ...);
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#include "debug.c"
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static inline size_t packet_header_size() {
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return offsetof(Packet, u);
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}
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static size_t packet_size(Packet *pkt) {
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return packet_header_size() + pkt->len;
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}
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static ssize_t write_all(int fd, const char *buf, size_t len) {
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debug("write_all(%d)\n", len);
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ssize_t ret = len;
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while (len > 0) {
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ssize_t res = write(fd, buf, len);
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if (res < 0) {
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if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
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continue;
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return -1;
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}
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if (res == 0)
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return ret - len;
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buf += res;
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len -= res;
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}
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return ret;
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}
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static ssize_t read_all(int fd, char *buf, size_t len) {
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debug("read_all(%d)\n", len);
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ssize_t ret = len;
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while (len > 0) {
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ssize_t res = read(fd, buf, len);
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if (res < 0) {
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if (errno == EWOULDBLOCK)
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return ret - len;
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if (errno == EAGAIN || errno == EINTR)
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continue;
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return -1;
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}
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if (res == 0)
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return ret - len;
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buf += res;
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len -= res;
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}
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return ret;
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}
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static bool send_packet(int socket, Packet *pkt) {
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size_t size = packet_size(pkt);
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if (size > sizeof(*pkt))
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return false;
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return write_all(socket, (char *)pkt, size) == size;
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}
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static bool recv_packet(int socket, Packet *pkt) {
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ssize_t len = read_all(socket, (char*)pkt, packet_header_size());
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if (len <= 0 || len != packet_header_size())
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return false;
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if (pkt->len > sizeof(pkt->u.msg)) {
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pkt->len = 0;
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return false;
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}
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if (pkt->len > 0) {
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len = read_all(socket, pkt->u.msg, pkt->len);
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if (len <= 0 || len != pkt->len)
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return false;
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}
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return true;
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}
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#include "client.c"
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#include "server.c"
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static void info(const char *str, ...) {
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va_list ap;
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va_start(ap, str);
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if (str) {
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fprintf(stderr, "%s: %s: ", server.name, server.session_name);
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vfprintf(stderr, str, ap);
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fprintf(stderr, "\r\n");
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}
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fflush(stderr);
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va_end(ap);
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}
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static void die(const char *s) {
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perror(s);
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exit(EXIT_FAILURE);
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}
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static void usage(void) {
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fprintf(stderr, "usage: abduco [-a|-A|-c|-C|-n] [-r] [-e detachkey] name command\n");
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exit(EXIT_FAILURE);
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}
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static int create_socket_dir(struct sockaddr_un *sockaddr) {
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size_t maxlen = sizeof(sockaddr->sun_path);
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char *dirs[] = { getenv("HOME"), getenv("TMPDIR"), "/tmp" };
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int socketfd = socket(AF_UNIX, SOCK_STREAM, 0);
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if (socketfd == -1)
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return -1;
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for (unsigned int i = 0; i < countof(dirs); i++) {
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char *dir = dirs[i];
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if (!dir)
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continue;
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int len = snprintf(sockaddr->sun_path, maxlen, "%s/.%s/", dir, server.name);
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if (len < 0 || (size_t)len >= maxlen)
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continue;
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if (mkdir(sockaddr->sun_path, 0750) == -1 && errno != EEXIST)
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continue;
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int len2 = snprintf(sockaddr->sun_path, maxlen, "%s/.%s/.abduco-%d", dir, server.name, getpid());
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if (len2 < 0 || (size_t)len2 >= maxlen)
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continue;
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socklen_t socklen = offsetof(struct sockaddr_un, sun_path) + strlen(sockaddr->sun_path) + 1;
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if (bind(socketfd, (struct sockaddr*)sockaddr, socklen) == -1)
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continue;
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unlink(sockaddr->sun_path);
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close(socketfd);
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sockaddr->sun_path[len] = '\0';
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return len;
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}
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close(socketfd);
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return -1;
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}
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static bool set_socket_name(struct sockaddr_un *sockaddr, const char *name) {
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size_t maxlen = sizeof(sockaddr->sun_path);
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if (name[0] == '/') {
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if (strlen(name) >= maxlen) {
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errno = ENAMETOOLONG;
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return false;
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}
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strncpy(sockaddr->sun_path, name, maxlen);
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} else if (name[0] == '.' && (name[1] == '.' || name[1] == '/')) {
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char buf[maxlen], *cwd = getcwd(buf, sizeof buf);
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if (!cwd)
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return false;
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int len = snprintf(sockaddr->sun_path, maxlen, "%s/%s", cwd, name);
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if (len < 0)
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return false;
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if ((size_t)len >= maxlen) {
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errno = ENAMETOOLONG;
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return false;
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}
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} else {
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int dir_len = create_socket_dir(sockaddr);
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if (dir_len == -1 || dir_len + strlen(name) + strlen(server.host) >= maxlen) {
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errno = ENAMETOOLONG;
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return false;
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}
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strncat(sockaddr->sun_path, name, maxlen - strlen(sockaddr->sun_path) - 1);
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strncat(sockaddr->sun_path, server.host, maxlen - strlen(sockaddr->sun_path) - 1);
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}
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return true;
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}
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static bool create_session(const char *name, char * const argv[]) {
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/* this uses the well known double fork strategy as described in section 1.7 of
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*
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* http://www.faqs.org/faqs/unix-faq/programmer/faq/
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*
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* pipes are used for synchronization and error reporting i.e. the child sets
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* the close on exec flag before calling execvp(3) the parent blocks on a read(2)
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* in case of failure the error message is written to the pipe, success is
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* indicated by EOF on the pipe.
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*/
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int client_pipe[2], server_pipe[2];
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pid_t pid;
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char errormsg[255];
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struct sigaction sa;
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if (pipe(client_pipe) == -1)
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return false;
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if ((server.socket = server_create_socket(name)) == -1)
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return false;
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switch ((pid = fork())) {
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case 0: /* child process */
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setsid();
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close(client_pipe[0]);
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switch ((pid = fork())) {
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case 0: /* child process */
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if (pipe(server_pipe) == -1) {
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snprintf(errormsg, sizeof(errormsg), "server-pipe: %s\n", strerror(errno));
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write_all(client_pipe[1], errormsg, strlen(errormsg));
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close(client_pipe[1]);
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_exit(EXIT_FAILURE);
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}
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sa.sa_flags = 0;
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sigemptyset(&sa.sa_mask);
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sa.sa_handler = server_pty_died_handler;
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sigaction(SIGCHLD, &sa, NULL);
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switch (server.pid = forkpty(&server.pty, NULL, has_term ? &server.term : NULL, &server.winsize)) {
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case 0: /* child = user application process */
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close(server.socket);
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close(server_pipe[0]);
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if (fcntl(client_pipe[1], F_SETFD, FD_CLOEXEC) == 0 &&
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fcntl(server_pipe[1], F_SETFD, FD_CLOEXEC) == 0)
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execvp(argv[0], argv);
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snprintf(errormsg, sizeof(errormsg), "server-execvp: %s: %s\n",
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argv[0], strerror(errno));
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write_all(client_pipe[1], errormsg, strlen(errormsg));
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write_all(server_pipe[1], errormsg, strlen(errormsg));
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close(client_pipe[1]);
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close(server_pipe[1]);
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_exit(EXIT_FAILURE);
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break;
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case -1: /* forkpty failed */
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snprintf(errormsg, sizeof(errormsg), "server-forkpty: %s\n", strerror(errno));
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write_all(client_pipe[1], errormsg, strlen(errormsg));
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close(client_pipe[1]);
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close(server_pipe[0]);
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close(server_pipe[1]);
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_exit(EXIT_FAILURE);
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break;
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default: /* parent = server process */
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sa.sa_handler = server_sigterm_handler;
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sigaction(SIGTERM, &sa, NULL);
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sigaction(SIGINT, &sa, NULL);
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sa.sa_handler = server_sigusr1_handler;
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sigaction(SIGUSR1, &sa, NULL);
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sa.sa_handler = SIG_IGN;
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sigaction(SIGPIPE, &sa, NULL);
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sigaction(SIGHUP, &sa, NULL);
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chdir("/");
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#ifdef NDEBUG
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int fd = open("/dev/null", O_RDWR);
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if (fd != -1) {
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dup2(fd, 0);
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dup2(fd, 1);
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dup2(fd, 2);
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close(fd);
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}
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#endif /* NDEBUG */
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close(client_pipe[1]);
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close(server_pipe[1]);
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if (read_all(server_pipe[0], errormsg, sizeof(errormsg)) > 0)
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_exit(EXIT_FAILURE);
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close(server_pipe[0]);
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server_mainloop();
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break;
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}
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break;
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case -1: /* fork failed */
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snprintf(errormsg, sizeof(errormsg), "server-fork: %s\n", strerror(errno));
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write_all(client_pipe[1], errormsg, strlen(errormsg));
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close(client_pipe[1]);
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_exit(EXIT_FAILURE);
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break;
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default: /* parent = intermediate process */
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close(client_pipe[1]);
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_exit(EXIT_SUCCESS);
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break;
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}
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break;
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case -1: /* fork failed */
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close(client_pipe[0]);
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close(client_pipe[1]);
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return false;
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default: /* parent = client process */
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close(client_pipe[1]);
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int status;
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wait(&status); /* wait for first fork */
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ssize_t len = read_all(client_pipe[0], errormsg, sizeof(errormsg));
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if (len > 0) {
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write_all(STDERR_FILENO, errormsg, len);
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unlink(sockaddr.sun_path);
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exit(EXIT_FAILURE);
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}
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close(client_pipe[0]);
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}
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return true;
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}
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static bool attach_session(const char *name, const bool terminate) {
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if (server.socket > 0)
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close(server.socket);
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if (!set_socket_name(&sockaddr, name) || (server.socket = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
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return false;
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socklen_t socklen = offsetof(struct sockaddr_un, sun_path) + strlen(sockaddr.sun_path) + 1;
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if (connect(server.socket, (struct sockaddr*)&sockaddr, socklen) == -1)
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return false;
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if (server_set_socket_non_blocking(server.socket) == -1)
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return false;
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struct sigaction sa;
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sa.sa_flags = 0;
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sigemptyset(&sa.sa_mask);
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sa.sa_handler = client_sigwinch_handler;
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sigaction(SIGWINCH, &sa, NULL);
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sa.sa_handler = SIG_IGN;
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sigaction(SIGPIPE, &sa, NULL);
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client_setup_terminal();
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int status = client_mainloop();
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client_restore_terminal();
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if (status == -1) {
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info("detached");
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} else if (status == -EIO) {
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info("exited due to I/O errors");
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} else {
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info("session terminated with exit status %d", status);
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if (terminate)
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exit(status);
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}
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return true;
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}
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static int session_filter(const struct dirent *d) {
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return strstr(d->d_name, server.host) != NULL;
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}
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static int session_comparator(const struct dirent **a, const struct dirent **b) {
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struct stat sa, sb;
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if (stat((*a)->d_name, &sa) != 0)
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return -1;
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if (stat((*b)->d_name, &sb) != 0)
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return 1;
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return sa.st_atime < sb.st_atime ? -1 : 1;
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}
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static int list_session(void) {
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if (create_socket_dir(&sockaddr) == -1)
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return 1;
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chdir(sockaddr.sun_path);
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struct dirent **namelist;
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int n = scandir(sockaddr.sun_path, &namelist, session_filter, session_comparator);
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if (n < 0)
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return 1;
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printf("Active sessions (on host %s)\n", server.host+1);
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while (n--) {
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struct stat sb; char buf[255];
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if (stat(namelist[n]->d_name, &sb) == 0 && S_ISSOCK(sb.st_mode)) {
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strftime(buf, sizeof(buf), "%a%t %F %T", localtime(&sb.st_atime));
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char status = ' ';
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if (sb.st_mode & S_IXUSR)
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status = '*';
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else if (sb.st_mode & S_IXGRP)
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status = '+';
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char *name = strstr(namelist[n]->d_name, server.host);
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if (name)
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*name = '\0';
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printf("%c %s\t%s\n", status, buf, namelist[n]->d_name);
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}
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free(namelist[n]);
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}
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free(namelist);
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return 0;
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}
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int main(int argc, char *argv[]) {
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char **cmd = NULL, action = '\0';
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server.name = basename(argv[0]);
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gethostname(server.host+1, sizeof(server.host) - 1);
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if (argc == 1)
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exit(list_session());
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for (int arg = 1; arg < argc; arg++) {
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if (argv[arg][0] != '-') {
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if (!server.session_name) {
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server.session_name = argv[arg];
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continue;
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} else if (!cmd) {
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cmd = &argv[arg];
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break;
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}
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}
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if (server.session_name)
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usage();
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switch (argv[arg][1]) {
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case 'a':
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case 'A':
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case 'c':
|
|
case 'C':
|
|
case 'n':
|
|
action = argv[arg][1];
|
|
break;
|
|
case 'e':
|
|
if (arg + 1 >= argc)
|
|
usage();
|
|
char *esc = argv[++arg];
|
|
if (esc[0] == '^' && esc[1])
|
|
*esc = CTRL(esc[1]);
|
|
KEY_DETACH = *esc;
|
|
break;
|
|
case 'r':
|
|
client.readonly = true;
|
|
break;
|
|
case 'v':
|
|
puts("abduco-"VERSION" © 2013-2015 Marc André Tanner");
|
|
exit(EXIT_SUCCESS);
|
|
default:
|
|
usage();
|
|
}
|
|
}
|
|
|
|
if (!cmd) {
|
|
cmd = (char*[]){ getenv("ABDUCO_CMD"), NULL };
|
|
if (!cmd[0])
|
|
cmd[0] = "dvtm";
|
|
}
|
|
|
|
if (!action || !server.session_name ||
|
|
((action == 'c' || action == 'C' || action == 'A') && client.readonly))
|
|
usage();
|
|
|
|
if (tcgetattr(STDIN_FILENO, &orig_term) != -1) {
|
|
server.term = orig_term;
|
|
has_term = true;
|
|
}
|
|
|
|
if (ioctl(STDIN_FILENO, TIOCGWINSZ, &server.winsize) == -1) {
|
|
server.winsize.ws_col = 80;
|
|
server.winsize.ws_row = 25;
|
|
}
|
|
|
|
server.read_pty = (action == 'n');
|
|
|
|
redo:
|
|
switch (action) {
|
|
case 'C':
|
|
if (set_socket_name(&sockaddr, server.session_name)) {
|
|
struct stat sb;
|
|
if (stat(sockaddr.sun_path, &sb) == 0 && S_ISSOCK(sb.st_mode)) {
|
|
if (sb.st_mode & S_IXGRP) {
|
|
/* Attach session in order to print old exit status */
|
|
attach_session(server.session_name, false);
|
|
} else {
|
|
info("session not yet terminated");
|
|
return 1;
|
|
}
|
|
}
|
|
}
|
|
case 'n':
|
|
case 'c':
|
|
if (!create_session(server.session_name, cmd))
|
|
die("create-session");
|
|
if (action == 'n')
|
|
break;
|
|
case 'a':
|
|
case 'A':
|
|
if (!attach_session(server.session_name, true)) {
|
|
if (action == 'A') {
|
|
action = 'c';
|
|
goto redo;
|
|
}
|
|
die("attach-session");
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|