add sshcd + fix bug

Signed-off-by: Mattias Andrée <m@maandree.se>

5 files changed, 260 insertions, 13 deletions

diff --git a/Makefile b/Makefile
index 9dc18bf..9812e19 100644
--- a/Makefile
+++ b/Makefile
@@ -21,11 +21,17 @@ install: sshexec
 	mkdir -p -- "$(DESTDIR)$(PREFIX)/bin"
 	mkdir -p -- "$(DESTDIR)$(MANPREFIX)/man1/"
 	cp -- sshexec "$(DESTDIR)$(PREFIX)/bin/"
+	test ! -d "$(DESTDIR)$(PREFIX)/bin/sshcd"
+	ln -sf -- sshexec "$(DESTDIR)$(PREFIX)/bin/sshcd"
 	cp -- sshexec.1 "$(DESTDIR)$(MANPREFIX)/man1/"
+	cp -- sshcd "$(DESTDIR)$(PREFIX)/bin/"
+	cp -- sshcd.1 "$(DESTDIR)$(MANPREFIX)/man1/"
 
 uninstall:
 	-rm -f -- "$(DESTDIR)$(PREFIX)/bin/sshexec"
 	-rm -f -- "$(DESTDIR)$(MANPREFIX)/man1/sshexec.1"
+	-rm -f -- "$(DESTDIR)$(PREFIX)/bin/sshcd"
+	-rm -f -- "$(DESTDIR)$(MANPREFIX)/man1/sshcd.1"
 
 clean:
 	-rm -f -- *.o *.a *.lo *.su *.so *.so.* *.gch *.gcov *.gcno *.gcda
diff --git a/README b/README
index b87c6d3..d7cbe87 100644
--- a/README
+++ b/README
@@ -158,4 +158,4 @@ BUGS
 	characters.
 
 SEE ALSO
-	ssh(1)
+	ssh(1), sshcd(1)
diff --git a/sshcd.1 b/sshcd.1
new file mode 100644
index 0000000..ba08414
--- /dev/null
+++ b/sshcd.1
@@ -0,0 +1,211 @@
+.TH SSHCD 1 sshexec
+
+.SH NAME
+sshcd - open ssh(1) with a specific remote working directory
+
+.SH SYNOPSIS
+.B sshcd
+.RB [ {
+.RI [\fBssh=\fP ssh-command ]
+.RB [ cd= ( strict | lax )]
+.BR } ]
+.RI [ ssh-option ]\ ...\,
+.I destination
+
+.SH DESCRIPTION
+The
+.B sshcd
+utility is a wrapper for SSH that makes it lets the user
+specify the directory remote working directory.
+.PP
+.B sshcd
+passes any argument after
+.B }
+to
+.I ssh-command
+.RB ( ssh
+if not specified), except it may rewrite
+.I destination
+to remove information that's not supported by
+.BR ssh (1).
+
+.SH OPTIONS
+.B sshcd
+options may be placed at the very beginning enclosed with
+the arguments
+.B {
+and
+.BR } .
+.B sshcd
+options, if any, shall be placed in the same
+.B {
+.BR } -group.
+Any other option will be passed as is to the
+.BR ssh (1)
+utility or
+.IR ssh-command .
+The
+.B sshcd
+utility has a build it list of options recognised by the
+.BR ssh (1)
+utility and will not allow anything matching this list.
+The
+.B sshcd
+utility does not allow mixing options and operands: no
+option may be placed after
+.IR destination .
+.PP
+The following
+.B sshcd
+options are supported:
+.TP
+.BI ssh= ssh-command
+Instead of looking for
+.B ssh
+in
+.IR PATH ,
+the
+.B sshcd
+utility shall use
+.IR ssh-command ,
+which it will look for in
+.I PATH
+if it is only a file name (does not contain a slash
+.RB ( / )).
+.TP
+.B cd=strict
+Fail without executing the
+.I command
+if it's not possible to set
+.I directory
+as the remote working directory.
+.TP
+.B cd=lax
+Continue (but warn) executing the
+.I command
+even if it's not possible to set
+.I directory
+as the remote working directory.
+
+.SH OPERANDS
+The following operands are supported:
+.TP
+.I destination
+The destination to connect and log into. It shall be either in
+the form
+.RI [ user\fP\fB@ ] hostname [\fB:\fP directory ]
+or in the form
+.BR ssh [ cd ] :// [\fIuser @ ]\fIhostname\fP[ : \fIport\fP][ / \fIdirectory\fP].
+
+.I user
+shall be the name of the remote user. If not specified,
+the name of the local user running the utility will be used.
+
+.I hostname
+shall be the address to the remote machine.
+
+.I port
+shall be the port or service name for the port to
+connect to on the remote machine.
+
+.I directory
+shall be directory to change the remote working directory.
+
+.SH STDIN
+The
+.B sshcd
+utility itself does not use the standard input.
+
+.SH INPUT FILES
+None.
+
+.SH ENVIRONMENT VARIABLES
+The following environment variables affects the execution of
+.BR sshcd :
+.TP
+.SH PATH
+Default. See to the Base Definitions volume of POSIX.1-2017, Section 8.3, Other Environment Variables.
+This environment variable affects where the
+.B sshcd
+utility can find the
+.BR ssh (1)
+utility or
+.IR ssh-command .
+.TP
+.B SSHCD_PTY_ALLOC_FLAG
+Specifies the option to pass to
+.BR ssh (1)
+to tell SSH to allocate a pseudo terminal. If unset
+.B -t
+will be used. If set but empty, no flag will be passed to
+.BR ssh (1).
+.PP
+Other environment variables may affect the execution of the
+.BR ssh (1)
+utility.
+
+.SH ASYNCHRONOUS EVENTS
+Default.
+
+.SH STDOUT
+The
+.B sshcd
+utility itself does not use the standard output.
+
+.SH STDERR
+The standard error is used for diagnostic messages in the
+.B sshcd
+utility itself.
+
+.SH OUTPUT FILES
+None.
+
+.SH EXTENDED DESCRIPTION
+None.
+
+.SH EXIT STATUS
+The
+.B sshcd
+utility exits with the exit status of the
+.BR ssh (1)
+utility or with 255 if an error occurred.
+
+.SH CONSEQUENCES OF ERRORS
+Default.
+
+.SH APPLICATION USAGE
+None.
+
+.SH EXAMPLES
+None.
+
+.SH RATIONALE
+For historical reasons, the
+.B sshcd
+utility does not let the user add a command to run
+inside the directory. This also avoids problems; if the
+user want to run a command in a specific directory,
+.BR sshexec (1)
+lets the user do so in an intuitive manner; for other
+traditional syntax,
+.BR ssh (1)
+can still be used — specifying a
+.BR cd (1)
+command at the beginning shouldn't be a problem.
+
+.SH NOTES
+None.
+
+.SH BUGS
+None.
+
+.SH FUTURE DIRECTIONS
+None.
+
+.SH SEE ALSO
+.BR ssh (1),
+.BR sshexec (1)
+
+.SH AUTHORS
+Mattias Andrée
+.RI < m@maandree.se >
diff --git a/sshexec.1 b/sshexec.1
index e824cb5..d4ace81 100644
--- a/sshexec.1
+++ b/sshexec.1
@@ -23,7 +23,7 @@ The
 .B sshexec
 utility is a wrapper for SSH that makes it easy to run commands
 directly in the SSH command.
-
+.PP
 .B sshexec
 passes any argument after
 .B }
@@ -369,7 +369,8 @@ as special characters.
 None.
 
 .SH SEE ALSO
-.BR ssh (1)
+.BR ssh (1),
+.BR sshcd (1)
 
 .SH AUTHORS
 Mattias Andrée
diff --git a/sshexec.c b/sshexec.c
index e0912c9..aca9ec9 100644
--- a/sshexec.c
+++ b/sshexec.c
@@ -10,6 +10,7 @@
 
 
 static const char *argv0 = "sshexec";
+static int is_sshcd = 0;
 
 
 #define exitf(...) (fprintf(stderr, __VA_ARGS__), exit(255))
@@ -18,9 +19,11 @@ static const char *argv0 = "sshexec";
 static void
 usage(void)
 {
-	exitf("usage: %s [{ %s }] [ssh-option] ... destination command [argument] ...\n",
-	      argv0, "[ssh=command] [dir=directory] [cd=(strict|lax)] [[fd]{>,>>,>|,<>}[&]=file] "
-	             "[asis=asis-marker [nasis=asis-count]]");
+	exitf("usage: %s [{ [ssh=command]%s [cd=(strict|lax)]%s }] [ssh-option] ... destination%s\n",
+	      argv0,
+	      is_sshcd ? "" : " [dir=directory]",
+	      is_sshcd ? "" : " [[fd]{>,>>,>|,<>}[&]=file] [asis=asis-marker [nasis=asis-count]]",
+	      is_sshcd ? "" : " command [argument] ...");
 }
 
 
@@ -153,6 +156,9 @@ main(int argc_unused, char *argv[])
 	if (*argv)
 		argv0 = *argv++;
 
+	p = strrchr(argv0, '/');
+	is_sshcd = !strcmp(p ? &p[1] : argv0, "sshcd");
+
 #define STORE_OPT(VARP, OPT)\
 	if (!strncmp(*argv, OPT"=", sizeof(OPT))) {\
 		if (*(VARP) || !*(*(VARP) = &(*argv)[sizeof(OPT)]))\
@@ -164,6 +170,11 @@ main(int argc_unused, char *argv[])
 		argv++;
 		for (; *argv && strcmp(*argv, "}"); argv++) {
 			STORE_OPT(&ssh, "ssh")
+			STORE_OPT(&cd, "cd")
+
+			if (is_sshcd)
+				usage();
+
 			STORE_OPT(&dir, "dir")
 			STORE_OPT(&asis, "asis")
 			STORE_OPT(&nasis_str, "nasis")
@@ -211,7 +222,9 @@ main(int argc_unused, char *argv[])
 	if (!ssh)
 		ssh = "ssh";
 
-	if (!cd || !strcmp(cd, "strict"))
+	if (!cd)
+		strict_cd = !is_sshcd;
+	else if (!strcmp(cd, "strict"))
 		strict_cd = 1;
 	else if (!strcmp(cd, "lax"))
 		strict_cd = 0;
@@ -259,19 +272,24 @@ main(int argc_unused, char *argv[])
 	}
 
 	destination = *argv++;
-	if (!destination || !*argv)
+	if (!destination || (is_sshcd ? !!*argv : !*argv))
 		usage();
 
-	if (!strcmp(*argv, "-"))
+	if (!strcmp(destination, "-"))
 		exitf("%s: the command argument must not be \"-\"\n", argv0);
-	else if (strchr(*argv, '='))
+	else if (strchr(destination, '='))
 		exitf("%s: the command argument must contain an \'=\'\n", argv0);
 
-	if (!strncmp(destination, "sshexec://", sizeof("sshexec://") - 1U)) {
+	if (!is_sshcd && !strncmp(destination, "sshexec://", sizeof("sshexec://") - 1U)) {
 		memmove(&destination[sizeof("ssh") - 1U],
 		        &destination[sizeof("sshexec") - 1U],
 		        strlen(&destination[sizeof("sshexec") - 1U]) + 1U);
 		goto using_ssh_prefix;
+	} else if (is_sshcd && !strncmp(destination, "sshcd://", sizeof("sshcd://") - 1U)) {
+		memmove(&destination[sizeof("ssh") - 1U],
+		        &destination[sizeof("sshcd") - 1U],
+		        strlen(&destination[sizeof("sshcd") - 1U]) + 1U);
+		goto using_ssh_prefix;
 	} else if (!strncmp(destination, "ssh://", sizeof("ssh://") - 1U)) {
 	using_ssh_prefix:
 		dest_dir_delim = strchr(&destination[sizeof("ssh://")], '/');
@@ -284,13 +302,16 @@ main(int argc_unused, char *argv[])
 		*dest_dir_delim++ = '\0';
 		dir = dest_dir_delim;
 	}
-dest_dir_checked:
 
 	if (dir) {
 		build_command_asis("cd -- ");
 		build_command_escape(dir);
 		build_command_asis(strict_cd ? " && " : " ; ");
 	}
+	if (is_sshcd) {
+		build_command_asis("exec \"$SHELL\" -l");
+		goto command_constructed;
+	}
 	if (asis)
 		build_command_asis("( env --");
 	else
@@ -320,13 +341,21 @@ dest_dir_checked:
 			build_command_escape(redirections[i].escape);
 		}
 	}
+command_constructed:
 	finalise_command();
 
 	i = 0;
-	args = calloc(5 + nopts, sizeof(*args));
+	args = calloc(5U + (size_t)is_sshcd + nopts, sizeof(*args));
 	if (!args)
 		exitf("%s: could not allocate enough memory\n", argv0);
 	args[i++] = ssh;
+	if (is_sshcd) {
+		const char *pty_alloc_flag = getenv("SSHCD_PTY_ALLOC_FLAG");
+		if (!pty_alloc_flag)
+			args[i++] = "-t";
+		else if (*pty_alloc_flag)
+			args[i++] = pty_alloc_flag;
+	}
 	memcpy(&args[i], opts, nopts * sizeof(*opts));
 	i += nopts;
 	args[i++] = "--";