diff options
| -rw-r--r-- | bin/dtch.c | 110 | ||||
| -rw-r--r-- | bin/man/dtch.1 | 22 |
2 files changed, 83 insertions, 49 deletions
diff --git a/bin/dtch.c b/bin/dtch.c index 4d9e527e..6e2b0072 100644 --- a/bin/dtch.c +++ b/bin/dtch.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2017, Curtis McEnroe <programble@gmail.com> +/* Copyright (C) 2017, 2018 Curtis McEnroe <june@causal.agency> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as published by @@ -18,13 +18,12 @@ #include <errno.h> #include <fcntl.h> #include <poll.h> -#include <pwd.h> #include <stdio.h> #include <stdlib.h> #include <sys/ioctl.h> #include <sys/socket.h> #include <sys/stat.h> -#include <sys/types.h> +#include <sys/stat.h> #include <sys/un.h> #include <sys/wait.h> #include <sysexits.h> @@ -39,12 +38,7 @@ #include <util.h> #endif -static struct passwd *getUser(void) { - uid_t uid = getuid(); - struct passwd *user = getpwuid(uid); - if (!user) err(EX_OSFILE, "/etc/passwd"); - return user; -} +typedef unsigned char byte; static struct sockaddr_un sockAddr(const char *home, const char *name) { struct sockaddr_un addr = { .sun_family = AF_UNIX }; @@ -52,12 +46,12 @@ static struct sockaddr_un sockAddr(const char *home, const char *name) { return addr; } -static char z; +static byte z; static struct iovec iov = { .iov_base = &z, .iov_len = 1 }; -static ssize_t sendFd(int sock, int fd) { +static ssize_t sendFD(int sock, int fd) { size_t size = CMSG_SPACE(sizeof(int)); - char buf[size]; + byte buf[size]; struct msghdr msg = { .msg_iov = &iov, .msg_iovlen = 1, @@ -74,7 +68,7 @@ static ssize_t sendFd(int sock, int fd) { return sendmsg(sock, &msg, 0); } -static int recvFd(int sock) { +static int recvFD(int sock) { size_t size = CMSG_SPACE(sizeof(int)); char buf[size]; struct msghdr msg = { @@ -84,7 +78,7 @@ static int recvFd(int sock) { .msg_controllen = size, }; - ssize_t n = recvmsg(sock, &msg, 0); + ssize_t n = recvmsg(sock, &msg, 0); if (n < 0) return -1; struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg); @@ -97,16 +91,16 @@ static int recvFd(int sock) { } static struct sockaddr_un addr; -static void unlinkAddr(void) { + +static void sigExit(int sig) { unlink(addr.sun_path); + _exit(128 + sig); } static int dtch(int argc, char *argv[]) { int error; - const struct passwd *user = getUser(); - - const char *name = user->pw_name; + const char *name = "dtch"; if (argc > 1) { name = argv[1]; argv++; @@ -115,35 +109,41 @@ static int dtch(int argc, char *argv[]) { if (argc > 1) { argv++; } else { - argv[0] = user->pw_shell; + argv[0] = getenv("SHELL"); + if (!argv[0]) argv[0] = "/bin/sh"; } - int home = open(user->pw_dir, 0); - if (home < 0) err(EX_CANTCREAT, "%s", user->pw_dir); + const char *home = getenv("HOME"); + if (!home) errx(EX_CONFIG, "HOME unset"); - error = mkdirat(home, ".dtch", 0700); - if (error && errno != EEXIST) err(EX_CANTCREAT, "%s/.dtch", user->pw_dir); + int fd = open(home, 0); + if (fd < 0) err(EX_CANTCREAT, "%s", home); - close(home); + error = mkdirat(fd, ".dtch", 0700); + if (error && errno != EEXIST) err(EX_CANTCREAT, "%s/.dtch", home); + + close(fd); int server = socket(PF_UNIX, SOCK_STREAM, 0); if (server < 0) err(EX_OSERR, "socket"); - addr = sockAddr(user->pw_dir, name); + addr = sockAddr(home, name); error = bind(server, (struct sockaddr *)&addr, sizeof(addr)); if (error) err(EX_CANTCREAT, "%s", addr.sun_path); fcntl(server, F_SETFD, FD_CLOEXEC); - atexit(unlinkAddr); int pty; pid_t pid = forkpty(&pty, NULL, NULL, NULL); if (pid < 0) err(EX_OSERR, "forkpty"); if (!pid) { - execvp(*argv, argv); - err(EX_NOINPUT, "%s", *argv); + execvp(argv[0], argv); + err(EX_NOINPUT, "%s", argv[0]); } + signal(SIGINT, sigExit); + signal(SIGTERM, sigExit); + error = listen(server, 0); if (error) err(EX_OSERR, "listen"); @@ -151,7 +151,7 @@ static int dtch(int argc, char *argv[]) { int client = accept(server, NULL, NULL); if (client < 0) err(EX_IOERR, "accept"); - ssize_t size = sendFd(client, pty); + ssize_t size = sendFD(client, pty); if (size < 0) warn("sendmsg"); size = recv(client, &z, sizeof(z), 0); @@ -161,8 +161,12 @@ static int dtch(int argc, char *argv[]) { int status; pid_t dead = waitpid(pid, &status, WNOHANG); - if (dead < 0) err(EX_OSERR, "waitpid(%d)", pid); - if (dead) return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE; + if (dead < 0) err(EX_OSERR, "waitpid"); + if (dead) { + unlink(addr.sun_path); + if (WIFEXITED(status)) return WEXITSTATUS(status); + else return 128 + WTERMSIG(status); + } } } @@ -172,32 +176,38 @@ static void restoreTerm(void) { printf("\x1B\x63"); // rs1 } +static void sigNop(int sig) { + (void)sig; +} + static int atch(int argc, char *argv[]) { int error; - const struct passwd *user = getUser(); - const char *name = (argc > 1) ? argv[1] : user->pw_name; + const char *home = getenv("HOME"); + if (!home) errx(EX_CONFIG, "HOME unset"); + + const char *name = (argc > 1) ? argv[1] : "dtch"; int client = socket(PF_UNIX, SOCK_STREAM, 0); if (client < 0) err(EX_OSERR, "socket"); - struct sockaddr_un addr = sockAddr(user->pw_dir, name); + struct sockaddr_un addr = sockAddr(home, name); error = connect(client, (struct sockaddr *)&addr, sizeof(addr)); if (error) err(EX_NOINPUT, "%s", addr.sun_path); - int pty = recvFd(client); + int pty = recvFD(client); if (pty < 0) err(EX_IOERR, "recvmsg"); struct winsize window; error = ioctl(STDIN_FILENO, TIOCGWINSZ, &window); - if (error) err(EX_IOERR, "TIOCGWINSZ"); + if (error) err(EX_IOERR, "ioctl"); struct winsize redraw = { .ws_row = 1, .ws_col = 1 }; error = ioctl(pty, TIOCSWINSZ, &redraw); - if (error) err(EX_IOERR, "TIOCSWINSZ"); + if (error) err(EX_IOERR, "ioctl"); error = ioctl(pty, TIOCSWINSZ, &window); - if (error) err(EX_IOERR, "TIOCSWINSZ"); + if (error) err(EX_IOERR, "ioctl"); error = tcgetattr(STDIN_FILENO, &saveTerm); if (error) err(EX_IOERR, "tcgetattr"); @@ -208,12 +218,27 @@ static int atch(int argc, char *argv[]) { error = tcsetattr(STDIN_FILENO, TCSADRAIN, &raw); if (error) err(EX_IOERR, "tcsetattr"); - char buf[4096]; + signal(SIGWINCH, sigNop); + + byte buf[4096]; struct pollfd fds[2] = { - { .fd = STDIN_FILENO, .events = POLLIN }, - { .fd = pty, .events = POLLIN }, + { .events = POLLIN, .fd = STDIN_FILENO }, + { .events = POLLIN, .fd = pty }, }; - while (0 < poll(fds, 2, -1)) { + for (;;) { + int n = poll(fds, 2, -1); + if (n < 0) { + if (errno != EINTR) err(EX_IOERR, "poll"); + + error = ioctl(STDIN_FILENO, TIOCGWINSZ, &window); + if (error) err(EX_IOERR, "ioctl"); + + error = ioctl(pty, TIOCSWINSZ, &window); + if (error) err(EX_IOERR, "ioctl"); + + continue; + } + if (fds[0].revents) { ssize_t size = read(STDIN_FILENO, buf, sizeof(buf)); if (size < 0) err(EX_IOERR, "read(%d)", STDIN_FILENO); @@ -232,7 +257,6 @@ static int atch(int argc, char *argv[]) { if (size < 0) err(EX_IOERR, "write(%d)", STDOUT_FILENO); } } - err(EX_IOERR, "poll"); } int main(int argc, char *argv[]) { diff --git a/bin/man/dtch.1 b/bin/man/dtch.1 index ad13c109..dd01c268 100644 --- a/bin/man/dtch.1 +++ b/bin/man/dtch.1 @@ -17,7 +17,11 @@ .Nm spawns the .Ar command -(by default, the user's shell) +.Po +by default, +the value of +.Ev SHELL +.Pc inside a new PTY. It then lends control of the detached PTY to .Nm atch @@ -35,11 +39,17 @@ session with the corresponding To detach from a session, type .Ic ^Q . . -.Sh FILES -.Bl -tag -.It Pa ~/.dtch/ Ns Ar name -UNIX-domain socket for the session -.Ar name . +.Sh ENVIRONMENT +.Bl -tag -width "SHELL" +.It Ev HOME +Location of +.Pa .dtch +directory for UNIX-domain sockets. +.It Ev SHELL +The default command to run, +or +.Pa /bin/sh +if unset. .El . .Sh EXAMPLES |