Reimplemented the communication with the FS shell for Unixish systems (now

including also Haiku) using FIFOs instead of Unix sockets. Advantages:
* Multiple FS shells can run concurrently, since they no longer need a unique
  address.
* Killing/aborting the build_haiku_image script will automatically tear down
  the FS shell as well, so there shouldn't be any stray FS shell processes
  anymore. Hopefully also fixes #5498.

So far only tested under Haiku.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40097 a95241bf-73f2-0310-859d-f6bbb57e9c96

build/scripts/build_haiku_image

@@ -72,6 +72,48 @@ if [ $isCD ]; then
 	mkdir=mkdir
 	rm=rm
 elif [ $isImage ]; then
+	# If FIFOs are used for the communication with the FS shell, prepare them.
+	if $fsShellCommand --uses-fifos; then
+		fifoBasePath=/tmp/build_haiku_image-$$-fifo
+		toFSShellFifo=${fifoBasePath}-to-shell
+		fromFSShellFifo=${fifoBasePath}-from-shell
+
+		rm -f $toFSShellFifo $fromFSShellFifo
+		mkfifo $toFSShellFifo $fromFSShellFifo
+
+		# Open the FIFOs such that they are ready for the fsShellCommand. This
+		# also makes sure that they remain open until this script exits. When we
+		# exit while the FS shell is still running and waiting for commands,
+		# closing of our file descriptors will break the pipes and the FS shell
+		# will exit, too.
+		exec 3<$fromFSShellFifo 4>$toFSShellFifo 5<$toFSShellFifo \
+			6>$fromFSShellFifo
+
+		# Remove the FIFO files again -- we have the open FDs, so they can
+		# still be used and this makes sure they won't hang around any further.
+		rm -f $toFSShellFifo $fromFSShellFifo
+
+		# Remap the fsShellCommand and bfsShell such that they don't inherit the
+		# wrong FDs. For both fsShellCommand and bfsShell FD 3 is the input from
+		# the respectively other program, FD 4 is the output to it.
+		actualFSShellCommand="$fsShellCommand"
+		actualBFSShell="$bfsShell"
+
+		fsShellCommandWrapper()
+		{
+			$actualFSShellCommand 5>&- 6>&- "$@"
+		}
+
+		bfsShellWrapper()
+		{
+			$actualBFSShell 3>&5 4<&6 "$@"
+		}
+
+		fsShellCommand=fsShellCommandWrapper
+		bfsShell=bfsShellWrapper
+	fi
+
+	# set up the other commands
 	sPrefix=:
 	tPrefix=/myfs/
 	cd="$fsShellCommand cd"
@@ -227,8 +269,16 @@ if [ $isImage ]; then
 			"$imageLabel" "block_size 2048"
 		$makebootable $imageOffsetFlags "$imagePath"
 	fi
+
 	$bfsShell -n $imageOffsetFlags "$imagePath" > /dev/null &
 	sleep 1
+
+	# Close FDs 5 and 6. Those represent the pipe ends that are used by the
+	# FS shell. Closing them in the shell process makes sure an unexpected death
+	# of the FS shell causes writing to/reading from the other ends to fail
+	# immediately.
+	exec 5>&- 6>&-
+
 	# bail out, if mounting fails
 	$cd .
 fi

src/tools/fs_shell/Jamfile

@@ -23,13 +23,14 @@ DEFINES += HAIKU_BUILD_COMPATIBILITY_H ;
 local fsShellCommandSources ;
 local externalCommandsSources ;
 local fsShellCommandLibs ;
-if $(HOST_PLATFORM_BEOS_COMPATIBLE) {
+if $(HOST_PLATFORM_BEOS_COMPATIBLE) && $(HOST_PLATFORM) != haiku_host {
+	# BeOS compatible, but not Haiku -- use BeOS ports for communication
 	fsShellCommandSources = fs_shell_command_beos.cpp ;
 	externalCommandsSources = external_commands_beos.cpp ;
 } else {
+	# Unix or Haiku -- use FIFOs for communication
 	fsShellCommandSources = fs_shell_command_unix.cpp ;
 	externalCommandsSources = external_commands_unix.cpp ;
-	fsShellCommandLibs = $(HOST_NETWORK_LIBS) ;
 }
 
 local kernelEmulationSources =

src/tools/fs_shell/external_commands_unix.cpp

@@ -1,180 +1,75 @@
 /*
- * Copyright 2005-2007, Ingo Weinhold, [email protected].de.
+ * Copyright 2005-2010, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
 
+
+#include "external_commands.h"
+
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
-#include <unistd.h>
-#include <sys/socket.h>
-#include <sys/un.h>
-
-#include "external_commands.h"
-#include "fs_shell_command_unix.h"
 
 
-static int sClientConnection = -1;
-
-
-static int
-get_command_socket()
+static FILE*
+get_input()
 {
-	static int fd = -1;
-	static bool initialized = false;
-	if (!initialized) {
-		// get the listener socket
-		fd = socket(AF_UNIX, SOCK_STREAM, 0);
-		if (fd < 0)
-			return -1;
-	
-		// bind it to the port
-		sockaddr_un addr;
-		unlink(kFSShellCommandSocketAddress);
-		addr.sun_family = AF_UNIX;
-		strcpy(addr.sun_path, kFSShellCommandSocketAddress);
-		int addrLen = addr.sun_path + strlen(addr.sun_path) + 1 - (char*)&addr;
-		if (bind(fd, (sockaddr*)&addr, addrLen) < 0) {
-			close(fd);
-			return -1;
-		}
-		
-		// start listening
-		if (listen(fd, 1) < 0) {
-			close(fd);
-			return -1;
-		}
-	
-		initialized = true;
-	}
-
-	return fd;
+	static FILE* sInput = fdopen(3, "r");
+	return sInput;
 }
 
 
-static int
-get_client_connection()
+static FILE*
+get_output()
 {
-	if (sClientConnection >= 0)
-		return sClientConnection;
-
-	// get the listener socket
-	int commandFD = get_command_socket();
-	if (commandFD < 0)
-		return -1;
-
-	// accept a connection
-	do {
-		sockaddr_un addr;
-		socklen_t addrLen = sizeof(addr);
-		sClientConnection = accept(commandFD, (sockaddr*)&addr, &addrLen);
-	} while (sClientConnection < 0 && errno == EINTR);
-
-	return sClientConnection;
-}
-
-
-static void
-close_client_connection()
-{
-	if (sClientConnection >= 0) {
-		close(sClientConnection);
-		sClientConnection = -1;
-	}
-}
-
-
-static bool
-read_data(int fd, void* _buffer, size_t toRead)
-{
-	char* buffer = (char*)_buffer;
-
-	ssize_t bytesRead = 0;
-	while (toRead > 0 && !(bytesRead < 0 && errno != EINTR)) {
-		bytesRead = read(fd, buffer, toRead);
-		if (bytesRead == 0)
-			break;
-		if (bytesRead > 0) {
-			buffer += bytesRead;
-			toRead -= bytesRead;
-		}
-	}
-
-	return (toRead == 0);
+	static FILE* sOutput = fdopen(4, "w");
+	return sOutput;
 }
 
 
 bool
-FSShell::get_external_command(char *input, int len)
+FSShell::get_external_command(char* buffer, int size)
 {
-	do {
-		// get a connection
-		int connection = get_client_connection();
-		if (connection < 0)
+	// get the input stream
+	FILE* in = get_input();
+	if (in == NULL) {
+		fprintf(stderr, "Error: Failed to open command input: %s\n",
+			strerror(errno));
+		return false;
+	}
+
+	while (true) {
+		// read a command line
+		if (fgets(buffer, size, in) != NULL)
+			return true;
+
+		// when interrupted, try again
+		if (errno != EINTR)
 			return false;
-
-		// read command message
-		external_command_message message;
-		if (!read_data(connection, &message, sizeof(message))) {
-			// that usually means the connection was closed
-			close_client_connection();
-			continue;
-		}
-
-		// check command length
-		if (message.command_length >= (unsigned)len) {
-			fprintf(stderr, "Error: Command too long!\n");
-			close_client_connection();
-			continue;
-		}
-
-		// read the command
-		if (!read_data(connection, input, message.command_length)) {
-			fprintf(stderr, "Error: Reading from connection failed: "
-				"%s\n", strerror(errno));
-			close_client_connection();
-			continue;
-		}
-
-		// null-terminate
-		input[message.command_length] = '\0';
-
-		return true;
-	
-	} while (true);
+	}
 }
 
 
 void
 FSShell::reply_to_external_command(int result)
 {
-	if (sClientConnection < 0)
+	// get the output stream
+	FILE* out = get_output();
+	if (out == NULL) {
+		fprintf(stderr, "Error: Failed to open command output: %s\n",
+			strerror(errno));
 		return;
+	}
 
-	// prepare the reply
-	external_command_reply reply;
-	reply.error = result;
-
-	// send the reply
-	int toWrite = sizeof(reply);
-	char *replyBuffer = (char*)&reply;
-	ssize_t bytesWritten;
-	do {
-		bytesWritten = write(sClientConnection, replyBuffer, toWrite);
-		if (bytesWritten > 0) {
-			replyBuffer += bytesWritten;
-			toWrite -= bytesWritten;
-		}
-	} while (toWrite > 0 && !(bytesWritten < 0 && errno != EINTR));
-
-	// connection may be broken: discard it
-	if (bytesWritten < 0)
-		close_client_connection();
+	if (fprintf(out, "%d\n", result) < 0 || fflush(out) == EOF) {
+		fprintf(stderr, "Error: Failed to write command reply to output reply: "
+			"%s\n", strerror(errno));
+	}
 }
 
 
 void
 FSShell::external_command_cleanup()
 {
-	unlink(kFSShellCommandSocketAddress);
+	// The file will be closed automatically when the team exits.
 }

src/tools/fs_shell/fs_shell_command.cpp

@@ -54,6 +54,9 @@ main(int argc, const char *const *argv)
 		exit(1);
 	}
 
+	if (strcmp(argv[1], "--uses-fifos") == 0)
+		exit(gUsesFifos ? 0 : 1);
+
 	// prepare the command string
 	char command[102400];
 	prepare_command_string(argv + 1, argc - 1, command, sizeof(command));

src/tools/fs_shell/fs_shell_command.h

@@ -6,6 +6,9 @@
 #define _FSSH_FS_SHELL_COMMAND_H
 
 
+extern bool gUsesFifos;
+
+
 bool	send_external_command(const char* command, int* result);
 
 

src/tools/fs_shell/fs_shell_command_beos.cpp

@@ -13,6 +13,9 @@
 #include "fs_shell_command.h"
 
 
+bool gUsesFifos = false;
+
+
 bool
 send_external_command(const char *command, int *result)
 {

src/tools/fs_shell/fs_shell_command_unix.cpp

@@ -1,103 +1,64 @@
 /*
- * Copyright 2005-2007, Ingo Weinhold, [email protected].de.
+ * Copyright 2005-2010, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
 
-#include "fs_shell_command_unix.h"
 
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
-#include <sys/socket.h>
-#include <sys/un.h>
 
 #include "fs_shell_command.h"
 
 
-static bool
-write_data(int fd, const void* _buffer, size_t toWrite)
-{
-	const char* buffer = (const char*)_buffer;
-
-	ssize_t bytesWritten;
-	do {
-		bytesWritten = write(fd, buffer, toWrite);
-		if (bytesWritten > 0) {
-			buffer += bytesWritten;
-			toWrite -= bytesWritten;
-		}
-	} while (toWrite > 0 && !(bytesWritten < 0 && errno != EINTR));
-
-	return (bytesWritten >= 0);
-}
+bool gUsesFifos = true;
 
 
 bool
-send_external_command(const char *command, int *result)
+send_external_command(const char* command, int* result)
 {
-	external_command_message message;
-	message.command_length = strlen(command);
-
-	// create a socket
-	int fd = socket(AF_UNIX, SOCK_STREAM, 0);
-	if (fd < 0) {
-		fprintf(stderr, "Error: Failed to open unix socket: %s\n",
+	// open the pipe to the FS shell
+	FILE* out = fdopen(4, "w");
+	if (out == NULL) {
+		fprintf(stderr, "Error: Failed to open command output: %s\n",
 			strerror(errno));
 		return false;
 	}
 
-	// connect to the fs_shell
-	sockaddr_un addr;
-	addr.sun_family = AF_UNIX;
-	strcpy(addr.sun_path, kFSShellCommandSocketAddress);
-	int addrLen = addr.sun_path + strlen(addr.sun_path) + 1 - (char*)&addr;
-	if (connect(fd, (sockaddr*)&addr, addrLen) < 0) {
-		fprintf(stderr, "Error: Failed to open connection to FS shell: %s\n",
+	// open the pipe from the FS shell
+	FILE* in = fdopen(3, "r");
+	if (in == NULL) {
+		fprintf(stderr, "Error: Failed to open command reply input: %s\n",
 			strerror(errno));
-		close(fd);
-		return false;
-	}
-	
-	// send the command message and the command
-	if (!write_data(fd, &message, sizeof(message))
-		|| !write_data(fd, command, message.command_length)) {
-		fprintf(stderr, "Error: Writing to fs_shell failed: %s\n",
-			strerror(errno));
-		close(fd);
 		return false;
 	}
 
-	// read the reply	
-	external_command_reply reply;
-	int toRead = sizeof(reply);
-	char *replyBuffer = (char*)&reply;
-	while (toRead > 0) {
-		int bytesRead = read(fd, replyBuffer, toRead);
-		if (bytesRead < 0) {
-			if (errno == EINTR) {
-				continue;
-			} else {
-				fprintf(stderr, "Error: Failed to read reply from fs_shell: "
-					"%s\n", strerror(errno));
-				close(fd);
-				return false;
-			}
-		}
-
-		if (bytesRead == 0) {
-			fprintf(stderr, "Error: Unexpected end of fs_shell reply. Was "
-				"still expecting %d bytes\n", toRead);
-			close(fd);
-			return false;
-		}
-		
-		replyBuffer += bytesRead;
-		toRead -= bytesRead;
+	// write the command
+	if (fputs(command, out) == EOF || fputc('\n', out) == EOF
+		|| fflush(out) == EOF) {
+		fprintf(stderr, "Error: Failed to write command to FS shell: %s\n",
+			strerror(errno));
+		return false;
+	}
+
+	// read the reply
+	char buffer[16];
+	if (fgets(buffer, sizeof(buffer), in) == NULL) {
+		fprintf(stderr, "Error: Failed to get command reply: %s\n",
+			strerror(errno));
+		return false;
+	}
+
+	// parse the number
+	char* end;
+	*result = strtol(buffer, &end, 10);
+	if (end == buffer) {
+		fprintf(stderr, "Error: Read non-number command reply from FS shell: "
+			"\"%s\"\n", buffer);
+		return false;
 	}
-	close(fd);
 
-	*result = reply.error;
 	return true;
 }
 

src/tools/fs_shell/fs_shell_command_unix.h

@@ -1,20 +0,0 @@
-/*
- * Copyright 2005-2007, Ingo Weinhold, [email protected].
- * Distributed under the terms of the MIT License.
- */
-#ifndef _FSSH_FS_SHELL_COMMAND_UNIX_H
-#define _FSSH_FS_SHELL_COMMAND_UNIX_H
-
-
-static const char *kFSShellCommandSocketAddress = "/tmp/fs_shell_commands";
-
-struct external_command_message {
-	unsigned	command_length;
-};
-
-struct external_command_reply {
-	int			error;
-};
-
-
-#endif	// _FSSH_FS_SHELL_COMMAND_UNIX_H