From 9a9e35b4ba108b63e7371ea37686040769ed0555 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Wed, 10 Feb 2016 09:59:45 +0000
Subject: [PATCH 01/17] Add a FUSE proxy written in C

This should improve portability, be more palatable for future
distribution, and enable lower-level control. Addresses #8.
---
 alpine/packages/transfused/.gitignore         |   1 +
 alpine/packages/transfused/Dockerfile         |  10 +
 alpine/packages/transfused/Makefile           |  15 +
 .../packages/transfused/etc/init.d/transfused |  32 ++
 alpine/packages/transfused/transfused.c       | 491 ++++++++++++++++++
 5 files changed, 549 insertions(+)
 create mode 100644 alpine/packages/transfused/.gitignore
 create mode 100644 alpine/packages/transfused/Dockerfile
 create mode 100644 alpine/packages/transfused/Makefile
 create mode 100755 alpine/packages/transfused/etc/init.d/transfused
 create mode 100644 alpine/packages/transfused/transfused.c

diff --git a/alpine/packages/transfused/.gitignore b/alpine/packages/transfused/.gitignore
new file mode 100644
index 000000000..ea662ae3a
--- /dev/null
+++ b/alpine/packages/transfused/.gitignore
@@ -0,0 +1 @@
+transfused
diff --git a/alpine/packages/transfused/Dockerfile b/alpine/packages/transfused/Dockerfile
new file mode 100644
index 000000000..d0c3197c0
--- /dev/null
+++ b/alpine/packages/transfused/Dockerfile
@@ -0,0 +1,10 @@
+FROM alpine:3.3
+
+RUN apk update && apk upgrade && apk add alpine-sdk
+
+RUN mkdir -p /transfused
+WORKDIR /transfused
+
+COPY . /transfused
+
+RUN make transfused
diff --git a/alpine/packages/transfused/Makefile b/alpine/packages/transfused/Makefile
new file mode 100644
index 000000000..d5739d5b7
--- /dev/null
+++ b/alpine/packages/transfused/Makefile
@@ -0,0 +1,15 @@
+.PHONY: all
+
+DEPS=transfused.c
+
+all: Dockerfile $(DEPS)
+	docker build -t transfused:build .
+	docker run transfused:build cat transfused > transfused
+	chmod 755 transfused
+
+transfused: $(DEPS)
+	gcc -g -static -Wall -Werror -o transfused transfused.c
+
+clean:
+	rm -f transfused
+	docker images -q transfused:build | xargs docker rmi -f
diff --git a/alpine/packages/transfused/etc/init.d/transfused b/alpine/packages/transfused/etc/init.d/transfused
new file mode 100755
index 000000000..06ee22a3b
--- /dev/null
+++ b/alpine/packages/transfused/etc/init.d/transfused
@@ -0,0 +1,32 @@
+#!/sbin/openrc-run
+
+description="fuse proxy server"
+
+depend()
+{
+	need 9pinit
+}
+
+start()
+{
+	[ -d /Transfuse ] || exit 0
+
+	ebegin "Starting FUSE socket passthrough"
+
+	[ -n "${PIDFILE}" ] || PIDFILE=/var/run/transfused.pid
+
+        /sbin/transfused &
+}
+
+stop()
+{
+	[ -d /Transfuse ] || exit 0
+
+	ebegin "Stopping FUSE socket passthrough"
+
+	[ -n "${PIDFILE}" ] || PIDFILE=/var/run/transfused.pid
+
+	start-stop-daemon --stop --quiet \
+		--pidfile "${PIDFILE}"
+	eend $? "Failed to stop transfused"
+}
diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
new file mode 100644
index 000000000..097a88bcf
--- /dev/null
+++ b/alpine/packages/transfused/transfused.c
@@ -0,0 +1,491 @@
+#include <sys/types.h>
+#include <errno.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <pthread.h>
+#include <signal.h>
+
+#define COPY_BUFSZ 65536
+
+int debug = 0;
+
+int save_trace;
+
+// execvpe is in unistd.h on Linux.
+int execvpe(const char *path, char *const argv[], char *const envp[]);
+
+typedef struct {
+  char * socket9p_root;
+} parameters;
+
+typedef struct {
+  parameters * params;
+  long id;
+} connection_state;
+
+typedef struct {
+  char * descr;
+  long connection;
+  char * tag;
+  int from;
+  int to;
+} copy_thread_state;
+
+char * fusermount = "fusermount";
+
+void * must_malloc(char *const descr, size_t size) {
+  void * ptr;
+
+  ptr = malloc(size);
+  if (size != 0 && ptr == NULL) {
+    perror(descr);
+    exit(1);
+  }
+
+  return ptr;
+}
+
+char ** read_opts(connection_state * connection, char * buf) {
+  int read_fd;
+  char * read_path;
+  int read_count;
+  int optc = 1;
+  char ** optv;
+
+  if (asprintf(&read_path, "%s/connections/%ld/read",
+               connection->params->socket9p_root, connection->id) == -1) {
+    fprintf(stderr, "Couldn't allocate read path\n");
+    exit(1);
+  }
+
+  read_fd = open(read_path, O_RDONLY);
+  if (read_fd == -1) {
+    fprintf(stderr, "For connection %ld, ", connection->id);
+    perror("couldn't open read path");
+    exit(1);
+  }
+
+  read_count = read(read_fd, buf, COPY_BUFSZ - 1);
+  if (read_count == -1) {
+    perror("read_opts error reading");
+    exit(1);
+  }
+  buf[read_count] = 0x0;
+
+  for (int i = 0; i < read_count; i++) {
+    if (buf[i] == 0x0) optc++;
+  }
+
+  optv = must_malloc("read_opts optv", (optc + 1) * sizeof(void *));
+  optv[0] = buf;
+  optv[optc] = 0x0;
+
+  int j = 1;
+  for (int i = 0; i < read_count && j < optc; i++) {
+    if (buf[i] == 0x0) {
+      optv[j] = buf + i + 1;
+      j++;
+    }
+  }
+
+  free(read_path);
+
+  return optv;
+}
+
+uint64_t message_id(char * message) {
+  return *((uint64_t *) (message + 8));
+}
+
+int copy(copy_thread_state * copy_state) {
+  int from = copy_state->from;
+  int to = copy_state->to;
+  char * descr = copy_state->descr;
+  int read_count, write_count;
+  long connection = copy_state->connection;
+  char * tag = copy_state->tag;
+  char * buf;
+
+  buf = must_malloc(descr, COPY_BUFSZ);
+
+  while(1) {
+    read_count = read(from, buf, COPY_BUFSZ);
+    if (read_count == -1) {
+      fprintf(stderr, "copy %s: error reading ", descr);
+      perror("");
+      exit(1);
+    }
+
+    if (save_trace) {
+      int trace_fd;
+      char * trace_path;
+
+      // TODO: check for errors
+      asprintf(&trace_path, "/tmp/transfused.%ld.%s.%llu",
+               connection, tag, message_id(buf));
+      trace_fd = open(trace_path, O_WRONLY | O_CREAT, 0600);
+      write(trace_fd, buf, read_count);
+      close(trace_fd);
+      free(trace_path);
+    }
+
+    write_count = write(to, buf, read_count);
+    if (write_count == -1) {
+      fprintf(stderr, "copy %s: error writing ", descr);
+      perror("");
+      exit(1);
+    }
+
+    if (write_count != read_count) {
+      fprintf(stderr, "copy %s: read %d but only wrote %d\n",
+              descr, read_count, write_count);
+      exit(1);
+    }
+  }
+
+  free(buf);
+  return 0;
+}
+
+int copy_clean_from(copy_thread_state * copy_state) {
+  int ret = copy(copy_state);
+
+  if (close(copy_state->from)) {
+    fprintf(stderr, "For %s, ", copy_state->descr);
+    perror("couldn't close read fd");
+    exit(1);
+  }
+
+  free(copy_state->descr);
+  free(copy_state);
+
+  return ret;
+}
+
+int copy_clean_to(copy_thread_state * copy_state) {
+  int ret = copy(copy_state);
+
+  if (close(copy_state->to)) {
+    fprintf(stderr, "For %s, ", copy_state->descr);
+    perror("couldn't close write fd");
+    exit(1);
+  }
+
+  free(copy_state->descr);
+  free(copy_state);
+
+  return ret;
+}
+
+int recv_fd(int sock) {
+  int ret;
+  int fd = -1;
+  char iochar;
+  char buf[CMSG_SPACE(sizeof(fd))];
+
+  struct msghdr msg;
+  struct iovec vec;
+  struct cmsghdr *cmsg;
+
+  msg.msg_name=NULL;
+  msg.msg_namelen=0;
+  vec.iov_base=&iochar;
+  vec.iov_len=1;
+  msg.msg_iov=&vec;
+
+  msg.msg_iovlen=1;
+
+  msg.msg_control = buf;
+  msg.msg_controllen = sizeof(buf);
+
+  ret = recvmsg(sock, &msg, 0);
+
+  if (ret == -1) {
+    perror("recvmsg");
+    exit(1);
+  }
+
+  if (ret > 0 && msg.msg_controllen > 0) {
+    cmsg = CMSG_FIRSTHDR(&msg);
+    if (cmsg->cmsg_level == SOL_SOCKET && (cmsg->cmsg_type == SCM_RIGHTS)) {
+      fd = *(int*)CMSG_DATA(cmsg);
+    } else {
+      fprintf(stderr, "recvmsg: failed to receive an fd\n");
+    }
+  }
+
+  return fd;
+}
+
+// optv must be null-terminated
+int get_fuse_sock(char *const optv[]) {
+  int optc;
+  char ** argv;
+  char * envp[2];
+  pid_t fusermount_pid;
+  int fuse_socks[2];
+  int status;
+  int fd;
+
+  // prepare argv from optv
+  for (optc = 0; optv[optc] != NULL; optc++) {}
+
+  argv = must_malloc("fusermount argv",(optc + 2) * sizeof(char *));
+
+  argv[0] = fusermount;
+  memcpy(&argv[1], optv, (optc + 1) * sizeof(char *));
+
+  // make the socket over which we'll be sent the FUSE socket fd
+  if (socketpair(PF_UNIX, SOCK_STREAM, 0, fuse_socks)) {
+    perror("Couldn't create FUSE socketpair");
+    exit(1);
+  }
+
+  // prepare to exec the suid binary fusermount
+  if (asprintf(&envp[0], "_FUSE_COMMFD=%d", fuse_socks[0]) == -1) {
+    fprintf(stderr, "Couldn't allocate fusermount envp\n");
+    exit(1);
+  }
+  envp[1] = 0x0;
+
+  // fork and exec fusermount
+  fusermount_pid = fork();
+  if (!fusermount_pid) { // child
+    if (execvpe(fusermount, argv, envp)) {
+      perror("Failed to execute fusermount");
+      exit(1);
+    }
+  }
+
+  // parent
+  free(argv);
+  free(envp[0]);
+
+  // close the end of the socket that we gave away
+  if (close(fuse_socks[0])) {
+    perror("Couldn't close unneeded fusermount socket");
+    exit(1);
+  }
+  
+  // wait for fusermount to return
+  waitpid(fusermount_pid, &status, 0);
+  if (!WIFEXITED(status)) {
+    fprintf(stderr, "fusermount terminated abnormally\n");
+    exit(1);
+  }
+  if (WEXITSTATUS(status)) {
+    fprintf(stderr, "fusermount exited with code %d\n", WEXITSTATUS(status));
+    exit(1);
+  }
+
+  if (debug) fprintf(stderr, "about to recv_fd from fusermount\n");
+
+  fd = recv_fd(fuse_socks[1]);
+  if (fd == -1) {
+    fprintf(stderr, "Couldn't receive fd over FUSE socket\n");
+    exit(1);
+  }
+
+  // close the read end of the socket
+  if (close(fuse_socks[1])) {
+    perror("Couldn't close fusermount read socket");
+    exit(1);
+  }
+
+  return fd;
+}
+
+int start_reader(connection_state * connection, int fuse) {
+  int read_fd;
+  char * read_path;
+  pthread_t child;
+  copy_thread_state * copy_state;
+  void *(*copy_clean)(void *) = (void *(*)(void *)) copy_clean_from;
+
+  if (asprintf(&read_path, "%s/connections/%ld/read",
+               connection->params->socket9p_root, connection->id) == -1) {
+    fprintf(stderr, "Couldn't allocate read path\n");
+    exit(1);
+  }
+
+  read_fd = open(read_path, O_RDONLY);
+  if (read_fd == -1) {
+    fprintf(stderr, "For connection %ld, ", connection->id);
+    perror("couldn't open read path");
+    exit(1);
+  }
+
+  copy_state = must_malloc("start_reader copy_state",
+                           sizeof(copy_thread_state));
+  copy_state->descr = read_path;
+  copy_state->connection = connection->id;
+  copy_state->tag = "read";
+  copy_state->from = read_fd;
+  copy_state->to = fuse;
+  if ((errno = pthread_create(&child, NULL, copy_clean, copy_state))) {
+    fprintf(stderr, "couldn't create read copy thread for connection %ld ",
+            connection->id);
+    perror("");
+    exit(1);
+  }
+
+  if ((errno = pthread_detach(child))) {
+    fprintf(stderr, "couldn't detach read copy thread for connection '%ld' ",
+            connection->id);
+    perror("");
+    exit(1);
+  }
+
+  return 0;
+}
+
+int start_writer(connection_state * connection, int fuse) {
+  int write_fd;
+  char * write_path;
+  copy_thread_state * copy_state;
+
+  if (asprintf(&write_path, "%s/connections/%ld/write",
+               connection->params->socket9p_root, connection->id) == -1) {
+    fprintf(stderr, "Couldn't allocate write path\n");
+    exit(1);
+  }
+
+  write_fd = open(write_path, O_WRONLY);
+  if (write_fd == -1) {
+    fprintf(stderr, "For connection %ld, ", connection->id);
+    perror("couldn't open write path");
+    exit(1);
+  }
+
+  copy_state = must_malloc("start_writer copy_state",
+                           sizeof(copy_thread_state));
+  copy_state->descr = write_path;
+  copy_state->connection = connection->id;
+  copy_state->tag = "write";
+  copy_state->from = fuse;
+  copy_state->to = write_fd;
+  copy_clean_to(copy_state);
+
+  return 0;
+}
+
+int handle_connection(connection_state * connection) {
+  char ** optv;
+  int fuse;
+  char * buf;
+  int ret;
+  
+  buf = must_malloc("read_opts packet malloc", COPY_BUFSZ);
+
+  optv = read_opts(connection, buf);
+  fuse = get_fuse_sock(optv);
+  free(optv);
+  free(buf);
+
+  start_reader(connection, fuse);
+  ret = start_writer(connection, fuse);
+  free(connection);
+
+  return ret;
+}
+
+void toggle_save_trace(int sig) {
+  save_trace = !save_trace;
+}
+
+void setup_save_trace() {
+  save_trace = 0;
+  
+  if (SIG_ERR == signal(SIGHUP, toggle_save_trace)) {
+    perror("Couldn't set SIGHUP behavior");
+    exit(1);
+  }
+
+  if (siginterrupt(SIGHUP, 1)) {
+    perror("Couldn't set siginterrupt for SIGHUP");
+    exit(1);
+  }
+}
+
+#define ID_LEN 512
+
+int main(int argc, char * argv[]) {
+  int events, read_count;
+  char buf[ID_LEN];
+  long conn;
+  pthread_t child;
+  void *(*handle)(void *) = (void *(*)(void *)) handle_connection;
+  parameters params;
+  connection_state * connection;
+  char * events_path;
+
+  if (argc < 2) {
+    params.socket9p_root = "/Transfuse";
+  } else {
+    params.socket9p_root = argv[1];
+  }
+
+  if (asprintf(&events_path, "%s/events", params.socket9p_root) == -1) {
+    fprintf(stderr, "Couldn't allocate events path\n");
+    exit(1);
+  }
+
+  setup_save_trace();
+
+  events = open(events_path, O_RDONLY | O_CLOEXEC);
+  while (events != -1) {
+    read_count = read(events, buf, ID_LEN - 1);
+    if (read_count == -1) {
+      perror("Error reading events path");
+      exit(1);
+    } else if (read_count == 0) {
+      // TODO: this is probably the 9p server's fault due to
+      //       not dropping the read 0 to force short read if
+      //       the real read is flushed
+      fprintf(stderr, "read 0 from event stream\n");
+      continue;
+    }
+
+    buf[read_count] = 0x0;
+
+    errno = 0;
+    conn = strtol(buf, NULL, 10);
+    if (errno) {
+      fprintf(stderr, "connection id of string '%s' ", buf);
+      perror("failed");
+      exit(1);
+    }
+
+    if (debug) fprintf(stderr, "handle connection %ld\n", conn);
+
+    connection = must_malloc("connection state", sizeof(connection_state));
+    connection->id = conn;
+    connection->params = &params;
+
+    if ((errno = pthread_create(&child, NULL, handle, connection))) {
+      fprintf(stderr, "couldn't create thread for connection '%ld' ", conn);
+      perror("");
+      exit(1);
+    }
+
+    if ((errno = pthread_detach(child))) {
+      fprintf(stderr, "couldn't detach thread for connection '%ld' ", conn);
+      perror("");
+      exit(1);
+    }
+
+    if (debug) fprintf(stderr, "thread spawned\n");
+  }
+
+  fprintf(stderr, "failed to open events path: %s\n", events_path);
+
+  free(events_path);
+  return 1;
+}

From 192c90b0a7ddcae3a0551b35fb6c2d708553902d Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Wed, 10 Feb 2016 10:05:44 +0000
Subject: [PATCH 02/17] Replace 9pudfuse with transfused

---
 alpine/Dockerfile                          | 6 +++---
 alpine/packages/Makefile                   | 6 +++---
 alpine/packages/diagnostics/diagnostics    | 4 ++--
 alpine/packages/docker/etc/init.d/docker   | 2 +-
 alpine/packages/hostlog/etc/init.d/hostlog | 2 +-
 xhyve/fuserun.sh                           | 2 +-
 6 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/alpine/Dockerfile b/alpine/Dockerfile
index 285dc7ab8..d287ea157 100644
--- a/alpine/Dockerfile
+++ b/alpine/Dockerfile
@@ -23,8 +23,8 @@ COPY mkinitrd.sh /bin/
 
 COPY packages/9pudc/9pudc /sbin/
 COPY packages/9pudc/etc /etc/
-COPY packages/9pudfuse/9pudfuse /sbin/
-COPY packages/9pudfuse/etc /etc/
+COPY packages/transfused/transfused /sbin/
+COPY packages/transfused/etc /etc/
 COPY packages/mdnstool/mdnstool /sbin/
 COPY packages/mdnstool/etc /etc/
 COPY packages/docker/docker /usr/bin/
@@ -78,7 +78,7 @@ RUN \
   rc-update add docker default && \
   rc-update add 9pinit boot && \
   rc-update add 9pudc default && \
-  rc-update add 9pudfuse default && \
+  rc-update add transfused default && \
   rc-update add mdnstool default && \
   rc-update add automount boot && \
   rc-update add diagnostics default && \
diff --git a/alpine/packages/Makefile b/alpine/packages/Makefile
index 995805a3e..014f78c59 100644
--- a/alpine/packages/Makefile
+++ b/alpine/packages/Makefile
@@ -1,6 +1,6 @@
 all:
 	$(MAKE) -C 9pudc
-	$(MAKE) -C 9pudfuse
+	$(MAKE) -C transfused
 	$(MAKE) -C mdnstool
 	$(MAKE) -C docker
 	$(MAKE) -C hupper
@@ -8,14 +8,14 @@ all:
 
 arm:
 	$(MAKE) -C 9pudc ARCH=arm
-	$(MAKE) -C 9pudfuse ARCH=arm
+	$(MAKE) -C transfused ARCH=arm
 	$(MAKE) -C mdnstool ARCH=arm
 	$(MAKE) -C docker ARCH=arm
 	$(MAKE) -C hupper ARCH=arm
 
 clean:
 	$(MAKE) -C 9pudc clean
-	$(MAKE) -C 9pudfuse clean
+	$(MAKE) -C transfused clean
 	$(MAKE) -C mdnstool clean
 	$(MAKE) -C docker clean
 	$(MAKE) -C hupper clean
diff --git a/alpine/packages/diagnostics/diagnostics b/alpine/packages/diagnostics/diagnostics
index 5ed2299e6..b81f24733 100755
--- a/alpine/packages/diagnostics/diagnostics
+++ b/alpine/packages/diagnostics/diagnostics
@@ -11,8 +11,8 @@ UDC=$(ps -eo args | grep '^/sbin/9pudc')
 [ $? -eq 0 ] && printf "✓ Process 9pudc running: $UDC\n" || printf "✗ No 9pudc process\n"
 if [ -d /Transfuse ]
 then
-	FUSE=$(ps -eo args | grep '^/sbin/9pudfuse')
-	[ $? -eq 0 ] && printf "✓ Process 9pudfuse running\n" || printf "✗ No 9pudfuse process\n"
+	FUSE=$(ps -eo args | grep '^/sbin/transfused')
+	[ $? -eq 0 ] && printf "✓ Process transfused running\n" || printf "✗ No transfused process\n"
 fi
 MDNS=$(ps -eo args | grep '^/sbin/mdnstool')
 [ $? -eq 0 ] && printf "✓ Process mdnstool running: $MDNS\n" || printf "✗ No mdnstool process\n"
diff --git a/alpine/packages/docker/etc/init.d/docker b/alpine/packages/docker/etc/init.d/docker
index 19231e9c5..90e6e725f 100755
--- a/alpine/packages/docker/etc/init.d/docker
+++ b/alpine/packages/docker/etc/init.d/docker
@@ -27,6 +27,6 @@ start_stop_daemon_args="--background \
 
 depend()
 {
-        after 9pudc 9pudfuse
+        after 9pudc transfused
         before chronyd
 }
diff --git a/alpine/packages/hostlog/etc/init.d/hostlog b/alpine/packages/hostlog/etc/init.d/hostlog
index b0e19cca5..f773ac8c0 100755
--- a/alpine/packages/hostlog/etc/init.d/hostlog
+++ b/alpine/packages/hostlog/etc/init.d/hostlog
@@ -3,7 +3,7 @@
 depends()
 {
 	before acpid docker syslog chronyd
-	after 9pinit 9pudfuse
+	after 9pinit transfused
 }
 
 start()
diff --git a/xhyve/fuserun.sh b/xhyve/fuserun.sh
index 3e57f2309..60742f031 100755
--- a/xhyve/fuserun.sh
+++ b/xhyve/fuserun.sh
@@ -17,7 +17,7 @@ fi
 #IMG_HDD="-s 4,virtio-blk,/somepath/somefile.img"
 PCI_DEV="-s 0:0,hostbridge -s 31,lpc"
 RND="-s 5,virtio-rnd"
-FS="-s 6,virtio-9p,path=9pudfuse.sock,tag=fuse"
+FS="-s 6,virtio-9p,path=transfused.sock,tag=fuse"
 LPC_DEV="-l com1,stdio"
 ACPI="-A"
 CLOCK="-u"

From 6384fbe0dcce5d96caeac1663980835cf6f197fc Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Wed, 10 Feb 2016 10:07:26 +0000
Subject: [PATCH 03/17] transfused: fix .gitignore

---
 alpine/packages/transfused/.gitignore | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/alpine/packages/transfused/.gitignore b/alpine/packages/transfused/.gitignore
index ea662ae3a..497a34c5f 100644
--- a/alpine/packages/transfused/.gitignore
+++ b/alpine/packages/transfused/.gitignore
@@ -1 +1 @@
-transfused
+/transfused

From 1efc36a38cefa8ebc18bca3d598931728fd960c3 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Wed, 10 Feb 2016 10:09:09 +0000
Subject: [PATCH 04/17] 9pudfuse: remove in favor of transfused

---
 alpine/packages/9pudfuse/.gitignore          |   1 -
 alpine/packages/9pudfuse/.merlin             |   6 -
 alpine/packages/9pudfuse/Dockerfile          |  13 --
 alpine/packages/9pudfuse/Makefile            |  11 --
 alpine/packages/9pudfuse/etc/init.d/9pudfuse |  37 ----
 alpine/packages/9pudfuse/fuse_socket_9p.ml   | 170 -------------------
 6 files changed, 238 deletions(-)
 delete mode 100644 alpine/packages/9pudfuse/.gitignore
 delete mode 100644 alpine/packages/9pudfuse/.merlin
 delete mode 100644 alpine/packages/9pudfuse/Dockerfile
 delete mode 100644 alpine/packages/9pudfuse/Makefile
 delete mode 100755 alpine/packages/9pudfuse/etc/init.d/9pudfuse
 delete mode 100644 alpine/packages/9pudfuse/fuse_socket_9p.ml

diff --git a/alpine/packages/9pudfuse/.gitignore b/alpine/packages/9pudfuse/.gitignore
deleted file mode 100644
index a9a5bb2c6..000000000
--- a/alpine/packages/9pudfuse/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-/9pudfuse
diff --git a/alpine/packages/9pudfuse/.merlin b/alpine/packages/9pudfuse/.merlin
deleted file mode 100644
index bde497c73..000000000
--- a/alpine/packages/9pudfuse/.merlin
+++ /dev/null
@@ -1,6 +0,0 @@
-PKG result
-PKG stringext
-PKG fd-send-recv
-
-S .
-B .
diff --git a/alpine/packages/9pudfuse/Dockerfile b/alpine/packages/9pudfuse/Dockerfile
deleted file mode 100644
index 82b0f4c44..000000000
--- a/alpine/packages/9pudfuse/Dockerfile
+++ /dev/null
@@ -1,13 +0,0 @@
-FROM ocaml/opam:alpine-3.3_ocaml-4.02.3
-
-ENV \
-  OPAMYES=true \
-  CAML_LD_LIBRARY_PATH="/root/.opam/4.02.3/lib/stublibs:/usr/pkg/lib/ocaml/stublibs" \
-  MANPATH="/root/.opam/4.02.3/man:" \
-  PERL5LIB="/root/.opam/4.02.3/lib/perl5" \
-  OCAML_TOPLEVEL_PATH="/root/.opam/4.02.3/lib/toplevel" \
-  PATH=/root/.opam/4.02.3/bin:$PATH
-
-COPY . .
-RUN opam depext -i result stringext fd-send-recv
-RUN opam config exec -- ocamlbuild -tag debug -use-ocamlfind -package stringext,fd-send-recv,result fuse_socket_9p.native
diff --git a/alpine/packages/9pudfuse/Makefile b/alpine/packages/9pudfuse/Makefile
deleted file mode 100644
index 78e5f6990..000000000
--- a/alpine/packages/9pudfuse/Makefile
+++ /dev/null
@@ -1,11 +0,0 @@
-all: 9pudfuse
-
-9pudfuse: Dockerfile fuse_socket_9p.ml
-	docker build -t 9pudfuse:build .
-	docker run --rm 9pudfuse:build \
-		cat fuse_socket_9p.native > 9pudfuse
-	chmod 755 9pudfuse
-
-clean:
-	rm -f 9pudfuse
-	docker images -q 9pudfuse:build | xargs docker rmi -f
diff --git a/alpine/packages/9pudfuse/etc/init.d/9pudfuse b/alpine/packages/9pudfuse/etc/init.d/9pudfuse
deleted file mode 100755
index 68bb02a54..000000000
--- a/alpine/packages/9pudfuse/etc/init.d/9pudfuse
+++ /dev/null
@@ -1,37 +0,0 @@
-#!/sbin/openrc-run
-
-description="9p socket fuse proxy server"
-
-depend()
-{
-	need 9pinit
-}
-
-start()
-{
-	[ -d /Transfuse ] || exit 0
-
-	ebegin "Starting FUSE socket passthrough"
-
-	[ -n "${PIDFILE}" ] || PIDFILE=/var/run/9pudfuse.pid
-
-#	start-stop-daemon --start --quiet \
-#		--exec /sbin/9pudfuse \
-#		--pidfile "${PIDFILE}" \
-#		-- -path /Transfuse
-#	eend $? "Failed to start 9pudfuse"
-        OCAMLRUNPARAM=b /sbin/9pudfuse &
-}
-
-stop()
-{
-	[ -d /Transfuse ] || exit 0
-
-	ebegin "Stopping FUSE socket passthrough"
-
-	[ -n "${PIDFILE}" ] || PIDFILE=/var/run/9pudfuse.pid
-
-	start-stop-daemon --stop --quiet \
-		--pidfile "${PIDFILE}"
-	eend $? "Failed to stop 9pudfuse"
-}
diff --git a/alpine/packages/9pudfuse/fuse_socket_9p.ml b/alpine/packages/9pudfuse/fuse_socket_9p.ml
deleted file mode 100644
index 104ce47f3..000000000
--- a/alpine/packages/9pudfuse/fuse_socket_9p.ml
+++ /dev/null
@@ -1,170 +0,0 @@
-
-exception ReadClosed
-
-let fusermount = "fusermount"
-let path = "/Transfuse"
-
-module Log = struct
-  let fatal fmt =
-    Printf.ksprintf (fun s -> prerr_endline s; exit 1) fmt
-  let error fmt =
-    Printf.ksprintf (fun s -> prerr_endline s) fmt
-  let info fmt =
-    Printf.ksprintf (fun s -> prerr_endline s) fmt
-end
-
-let events_path = path ^ "/events"
-
-let try_fork caller_name =
-  try
-    Unix.fork ()
-  with Unix.Unix_error (err,"fork",_) ->
-    Log.fatal "%s fork failed: %s" caller_name (Unix.error_message err)
-
-let check_status = function
-  | Unix.WEXITED 0 -> Result.Ok ()
-  | Unix.WEXITED k ->
-    Result.Error ("exit code "^(string_of_int k))
-  | Unix.WSIGNALED k ->
-    Result.Error ("ocaml kill signal "^(string_of_int k))
-  | Unix.WSTOPPED k ->
-    Result.Error ("ocaml stop signal "^(string_of_int k))
-
-let finally f at_end =
-  let r = try f () with e -> (at_end (); raise e) in
-  at_end ();
-  r
-
-let copy description dst src =
-  let sz = 1 lsl 16 in
-  let buf = Bytes.create sz in
-  (*let pnum = ref 0 in*)
-  let rec loop () =
-    let n = Unix.read src buf 0 sz in
-    (if n = 0 then raise ReadClosed);
-(*
-    let fd = Unix.(
-      openfile ("/tmp/"^description^"_"^(string_of_int !pnum))
-        [O_WRONLY; O_CREAT] 0o600) in
-    let k = Unix.write fd buf 0 n in
-    assert (k = n);
-    Unix.close fd;
-    incr pnum;
-*)
-    let written = try
-        Unix.write dst buf 0 n
-      with
-      | Unix.Unix_error (Unix.EINVAL, "write", _) ->
-        failwith ("copy write for "^description^" failed with EINVAL")
-      | Unix.Unix_error (Unix.ENOENT, "write", _) ->
-        failwith ("copy write for "^description^" failed with ENOENT")
-    in
-    (if n <> written
-     then Log.error "copy of %s read %d but wrote %d" description n written);
-    loop ()
-  in
-  try loop ()
-  with
-  | ReadClosed -> raise ReadClosed
-  | e -> (Log.error "copy for %s failed" description; raise e)
-
-let with_reader id f =
-  let read_path = Printf.sprintf "%s/connections/%d/read" path id in
-  let read_fd = Unix.(openfile read_path [O_RDONLY] 0o000) in
-  try finally (fun () ->
-    f read_path read_fd
-  ) (fun () ->
-    Unix.close read_fd
-  ) with
-  | ReadClosed -> exit 0
-
-let with_writer id f =
-  let write_path = Printf.sprintf "%s/connections/%d/write" path id in
-  let write_fd = Unix.(openfile write_path [O_WRONLY] 0o000) in
-  finally (fun () ->
-    f write_path write_fd
-  ) (fun () ->
-    Unix.close write_fd;
-    Unix.unlink write_path
-  )
-
-let read_opts id = with_reader id (fun read_path read_fd ->
-  let sz = 512 in
-  let buf = Bytes.create sz in
-  let n = Unix.read read_fd buf 0 sz in
-  let opts = Stringext.split ~on:'\000' (Bytes.sub buf 0 n) in
-  Array.of_list opts
-)
-
-let get_fuse_sock opts =
-  let wsock, rsock = Unix.(socketpair PF_UNIX SOCK_STREAM 0) in
-  let wfd = Fd_send_recv.int_of_fd wsock in
-  let opts = Array.append [|fusermount|] opts in
-  let pid = Unix.(create_process_env fusermount opts
-                    [|"_FUSE_COMMFD="^(string_of_int wfd)|]
-                    stdin stdout stderr) in
-  let _, status = Unix.waitpid [] pid in
-  let () = Unix.(shutdown wsock SHUTDOWN_ALL) in
-  match check_status status with
-  | Result.Error str ->
-    let opts = String.concat " " (Array.to_list opts) in
-    Log.fatal "%s: %s" opts str
-  | Result.Ok () ->
-    (* We must read at least 1 byte, by POSIX! *)
-    let _, _, fd = Fd_send_recv.recv_fd rsock "\000" 0 1 [] in
-    let () = Unix.(shutdown rsock SHUTDOWN_ALL) in
-    fd
-
-(* readers fork into a new process *)
-let start_reader id fuse =
-  match try_fork "start_reader" with
-  | 0 -> (* child *)
-    with_reader id (fun _read_path read_fd ->
-      copy ("reader_"^string_of_int id) fuse read_fd
-    )
-  | _child_pid -> (* parent *)
-    ()
-
-(* writers stay in the calling process *)
-let start_writer id fuse = with_writer id (fun write_path write_fd ->
-  copy ("writer_"^string_of_int id) write_fd fuse
-)
-
-let handle_connection id =
-  Log.info "handle_connection %d" id;
-  match try_fork "handle_connection" with
-  | 0 -> (* child *)
-    let opts = read_opts id in
-    let fuse = get_fuse_sock opts in
-    start_reader id fuse;
-    begin try ignore (start_writer id fuse); exit 0
-      with
-      | e -> prerr_endline (Printexc.to_string e); exit 1
-    end
-  | _child_pid -> (* parent *)
-    ()
-
-let connection_loop () =
-  let events = Unix.(openfile events_path [O_RDONLY] 0o000) in
-  (* 512 bytes is easily big enough to read a whole connection id *)
-  let sz = 512 in
-  let buf = Bytes.create sz in
-  let rec recv () =
-    begin try
-        let n = Unix.read events buf 0 sz in
-        let s = String.trim Bytes.(to_string (sub buf 0 n)) in
-        let id = int_of_string s in
-        handle_connection id;
-      with
-      | Unix.Unix_error (err,"read",path) ->
-        Log.fatal "Error reading events file %s: %s"
-          path (Unix.error_message err)
-      | Failure "int_of_string" ->
-        Log.fatal "Failed to parse integer connection id"
-    end;
-    recv ()
-  in
-  recv ()
-
-;;
-connection_loop ()

From 7ab2f3816c1ead09683415dc89898eb50a39f641 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Wed, 10 Feb 2016 17:09:11 +0000
Subject: [PATCH 05/17] transfused: address @yallop's comments

---
 alpine/packages/transfused/transfused.c | 336 ++++++++++--------------
 1 file changed, 136 insertions(+), 200 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 097a88bcf..7e398d69d 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -3,6 +3,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <stdarg.h>
 
 #include <stdio.h>
 #include <unistd.h>
@@ -40,14 +41,20 @@ typedef struct {
 
 char * fusermount = "fusermount";
 
+void die(int exit_code, const char * perror_arg, const char * fmt, ...) {
+  va_list argp;
+  va_start(argp, fmt);
+  vfprintf(stderr, fmt, argp);
+  va_end(argp);
+  if (perror_arg != NULL) perror(perror_arg);
+  exit(exit_code);
+}
+
 void * must_malloc(char *const descr, size_t size) {
   void * ptr;
 
   ptr = malloc(size);
-  if (size != 0 && ptr == NULL) {
-    perror(descr);
-    exit(1);
-  }
+  if (size != 0 && ptr == NULL) die(1,descr,"");
 
   return ptr;
 }
@@ -60,30 +67,23 @@ char ** read_opts(connection_state * connection, char * buf) {
   char ** optv;
 
   if (asprintf(&read_path, "%s/connections/%ld/read",
-               connection->params->socket9p_root, connection->id) == -1) {
-    fprintf(stderr, "Couldn't allocate read path\n");
-    exit(1);
-  }
+               connection->params->socket9p_root, connection->id) == -1)
+    die(1,"Couldn't allocate read path","");
 
   read_fd = open(read_path, O_RDONLY);
-  if (read_fd == -1) {
-    fprintf(stderr, "For connection %ld, ", connection->id);
-    perror("couldn't open read path");
-    exit(1);
-  }
+  if (read_fd == -1)
+    die(1,"couldn't open read path", "For connection %ld, ", connection->id);
 
   read_count = read(read_fd, buf, COPY_BUFSZ - 1);
-  if (read_count == -1) {
-    perror("read_opts error reading");
-    exit(1);
-  }
+  if (read_count == -1) die(1,"read_opts error reading", "");
+
   buf[read_count] = 0x0;
 
   for (int i = 0; i < read_count; i++) {
     if (buf[i] == 0x0) optc++;
   }
 
-  optv = must_malloc("read_opts optv", (optc + 1) * sizeof(void *));
+  optv = (char **) must_malloc("read_opts optv", (optc + 1) * sizeof(void *));
   optv[0] = buf;
   optv[optc] = 0x0;
 
@@ -100,28 +100,24 @@ char ** read_opts(connection_state * connection, char * buf) {
   return optv;
 }
 
-uint64_t message_id(char * message) {
-  return *((uint64_t *) (message + 8));
+uint64_t message_id(uint64_t * message) {
+  return message[1];
 }
 
-int copy(copy_thread_state * copy_state) {
+void copy(copy_thread_state * copy_state) {
   int from = copy_state->from;
   int to = copy_state->to;
   char * descr = copy_state->descr;
   int read_count, write_count;
   long connection = copy_state->connection;
   char * tag = copy_state->tag;
-  char * buf;
+  void * buf;
 
   buf = must_malloc(descr, COPY_BUFSZ);
 
   while(1) {
     read_count = read(from, buf, COPY_BUFSZ);
-    if (read_count == -1) {
-      fprintf(stderr, "copy %s: error reading ", descr);
-      perror("");
-      exit(1);
-    }
+    if (read_count == -1) die(1, "", "copy %s: error reading: ", descr);
 
     if (save_trace) {
       int trace_fd;
@@ -137,51 +133,42 @@ int copy(copy_thread_state * copy_state) {
     }
 
     write_count = write(to, buf, read_count);
-    if (write_count == -1) {
-      fprintf(stderr, "copy %s: error writing ", descr);
-      perror("");
-      exit(1);
-    }
+    if (write_count == -1) die(1, "", "copy %s: error writing: ", descr);
 
-    if (write_count != read_count) {
-      fprintf(stderr, "copy %s: read %d but only wrote %d\n",
-              descr, read_count, write_count);
-      exit(1);
-    }
+    if (write_count != read_count)
+      die(1, NULL, "copy %s: read %d by only wrote %d\n",
+          descr, read_count, write_count);
   }
 
   free(buf);
-  return 0;
 }
 
-int copy_clean_from(copy_thread_state * copy_state) {
-  int ret = copy(copy_state);
+void * copy_clean_from(copy_thread_state * copy_state) {
+  copy(copy_state);
 
-  if (close(copy_state->from)) {
-    fprintf(stderr, "For %s, ", copy_state->descr);
-    perror("couldn't close read fd");
-    exit(1);
-  }
+  if (close(copy_state->from))
+    die(1, "couldn't close read fd", "For %s, ", copy_state->descr);
 
   free(copy_state->descr);
   free(copy_state);
 
-  return ret;
+  return NULL;
 }
 
-int copy_clean_to(copy_thread_state * copy_state) {
-  int ret = copy(copy_state);
+void * copy_clean_from_thread(void * copy_state) {
+  return (copy_clean_from((copy_thread_state *) copy_state));
+}
 
-  if (close(copy_state->to)) {
-    fprintf(stderr, "For %s, ", copy_state->descr);
-    perror("couldn't close write fd");
-    exit(1);
-  }
+void * copy_clean_to(copy_thread_state * copy_state) {
+  copy(copy_state);
+
+  if (close(copy_state->to))
+    die(1, "couldn't close write fd", "For %s, ", copy_state->descr);
 
   free(copy_state->descr);
   free(copy_state);
 
-  return ret;
+  return NULL;
 }
 
 int recv_fd(int sock) {
@@ -207,17 +194,12 @@ int recv_fd(int sock) {
 
   ret = recvmsg(sock, &msg, 0);
 
-  if (ret == -1) {
-    perror("recvmsg");
-    exit(1);
-  }
+  if (ret == -1) die(1,"recvmsg","");
 
   if (ret > 0 && msg.msg_controllen > 0) {
     cmsg = CMSG_FIRSTHDR(&msg);
     if (cmsg->cmsg_level == SOL_SOCKET && (cmsg->cmsg_type == SCM_RIGHTS)) {
       fd = *(int*)CMSG_DATA(cmsg);
-    } else {
-      fprintf(stderr, "recvmsg: failed to receive an fd\n");
     }
   }
 
@@ -237,152 +219,116 @@ int get_fuse_sock(char *const optv[]) {
   // prepare argv from optv
   for (optc = 0; optv[optc] != NULL; optc++) {}
 
-  argv = must_malloc("fusermount argv",(optc + 2) * sizeof(char *));
+  argv = (char **) must_malloc("fusermount argv",(optc + 2) * sizeof(char *));
 
   argv[0] = fusermount;
   memcpy(&argv[1], optv, (optc + 1) * sizeof(char *));
 
   // make the socket over which we'll be sent the FUSE socket fd
-  if (socketpair(PF_UNIX, SOCK_STREAM, 0, fuse_socks)) {
-    perror("Couldn't create FUSE socketpair");
-    exit(1);
-  }
+  if (socketpair(PF_UNIX, SOCK_STREAM, 0, fuse_socks))
+    die(1, "Couldn't create FUSE socketpair", "");
 
   // prepare to exec the suid binary fusermount
-  if (asprintf(&envp[0], "_FUSE_COMMFD=%d", fuse_socks[0]) == -1) {
-    fprintf(stderr, "Couldn't allocate fusermount envp\n");
-    exit(1);
-  }
+  if (asprintf(&envp[0], "_FUSE_COMMFD=%d", fuse_socks[0]) == -1)
+    die(1, "", "Couldn't allocate fusermount envp");
+
   envp[1] = 0x0;
 
   // fork and exec fusermount
   fusermount_pid = fork();
-  if (!fusermount_pid) { // child
-    if (execvpe(fusermount, argv, envp)) {
-      perror("Failed to execute fusermount");
-      exit(1);
-    }
-  }
+  if (!fusermount_pid) // child
+    if (execvpe(fusermount, argv, envp))
+      die(1, "Failed to execute fusermount", "");
 
   // parent
   free(argv);
   free(envp[0]);
 
   // close the end of the socket that we gave away
-  if (close(fuse_socks[0])) {
-    perror("Couldn't close unneeded fusermount socket");
-    exit(1);
-  }
-  
+  if (close(fuse_socks[0]))
+    die(1, "Couldn't close unneeded fusermount socket", "");
+
   // wait for fusermount to return
   waitpid(fusermount_pid, &status, 0);
-  if (!WIFEXITED(status)) {
-    fprintf(stderr, "fusermount terminated abnormally\n");
-    exit(1);
-  }
-  if (WEXITSTATUS(status)) {
-    fprintf(stderr, "fusermount exited with code %d\n", WEXITSTATUS(status));
-    exit(1);
-  }
+  if (!WIFEXITED(status))
+    die(1, NULL, "fusermount terminated abnormally\n");
+
+  if (WEXITSTATUS(status))
+    die(1, NULL, "fusermount exited with code %d\n", WEXITSTATUS(status));
 
   if (debug) fprintf(stderr, "about to recv_fd from fusermount\n");
 
   fd = recv_fd(fuse_socks[1]);
-  if (fd == -1) {
-    fprintf(stderr, "Couldn't receive fd over FUSE socket\n");
-    exit(1);
-  }
+  if (fd == -1)
+    die(1, NULL, "Couldn't receive fd over FUSE socket\n");
 
   // close the read end of the socket
-  if (close(fuse_socks[1])) {
-    perror("Couldn't close fusermount read socket");
-    exit(1);
-  }
+  if (close(fuse_socks[1]))
+    die(1, "Couldn't close fusermount read socket", "");
 
   return fd;
 }
 
-int start_reader(connection_state * connection, int fuse) {
+void start_reader(connection_state * connection, int fuse) {
   int read_fd;
   char * read_path;
   pthread_t child;
   copy_thread_state * copy_state;
-  void *(*copy_clean)(void *) = (void *(*)(void *)) copy_clean_from;
 
   if (asprintf(&read_path, "%s/connections/%ld/read",
-               connection->params->socket9p_root, connection->id) == -1) {
-    fprintf(stderr, "Couldn't allocate read path\n");
-    exit(1);
-  }
+               connection->params->socket9p_root, connection->id) == -1)
+    die(1, "", "Couldn't allocate read path: ");
 
   read_fd = open(read_path, O_RDONLY);
-  if (read_fd == -1) {
-    fprintf(stderr, "For connection %ld, ", connection->id);
-    perror("couldn't open read path");
-    exit(1);
-  }
+  if (read_fd == -1)
+    die(1, "couldn't open read path", "For connection %ld, ", connection->id);
 
-  copy_state = must_malloc("start_reader copy_state",
-                           sizeof(copy_thread_state));
+  copy_state = (copy_thread_state *) must_malloc("start_reader copy_state",
+                                                 sizeof(copy_thread_state));
   copy_state->descr = read_path;
   copy_state->connection = connection->id;
   copy_state->tag = "read";
   copy_state->from = read_fd;
   copy_state->to = fuse;
-  if ((errno = pthread_create(&child, NULL, copy_clean, copy_state))) {
-    fprintf(stderr, "couldn't create read copy thread for connection %ld ",
-            connection->id);
-    perror("");
-    exit(1);
-  }
+  if ((errno = pthread_create(&child, NULL,
+                              copy_clean_from_thread, copy_state)))
+    die(1, "", "couldn't create read copy thread for connection %ld: ",
+        connection->id);
 
-  if ((errno = pthread_detach(child))) {
-    fprintf(stderr, "couldn't detach read copy thread for connection '%ld' ",
-            connection->id);
-    perror("");
-    exit(1);
-  }
-
-  return 0;
+  if ((errno = pthread_detach(child)))
+    die (1, "", "couldn't detach read copy thread for connection '%ld': ",
+         connection->id);
 }
 
-int start_writer(connection_state * connection, int fuse) {
+void do_write(connection_state * connection, int fuse) {
   int write_fd;
   char * write_path;
   copy_thread_state * copy_state;
 
   if (asprintf(&write_path, "%s/connections/%ld/write",
-               connection->params->socket9p_root, connection->id) == -1) {
-    fprintf(stderr, "Couldn't allocate write path\n");
-    exit(1);
-  }
+               connection->params->socket9p_root, connection->id) == -1)
+    die(1, "", "Couldn't allocate write path: ");
 
   write_fd = open(write_path, O_WRONLY);
-  if (write_fd == -1) {
-    fprintf(stderr, "For connection %ld, ", connection->id);
-    perror("couldn't open write path");
-    exit(1);
-  }
+  if (write_fd == -1)
+    die(1, "couldn't open write path", "For connection %ld, ", connection->id);
 
-  copy_state = must_malloc("start_writer copy_state",
-                           sizeof(copy_thread_state));
+  copy_state = (copy_thread_state *) must_malloc("do_write copy_state",
+                                                 sizeof(copy_thread_state));
   copy_state->descr = write_path;
   copy_state->connection = connection->id;
   copy_state->tag = "write";
   copy_state->from = fuse;
   copy_state->to = write_fd;
   copy_clean_to(copy_state);
-
-  return 0;
 }
 
-int handle_connection(connection_state * connection) {
+void * handle_connection(connection_state * connection) {
   char ** optv;
   int fuse;
   char * buf;
-  int ret;
   
-  buf = must_malloc("read_opts packet malloc", COPY_BUFSZ);
+  buf = (char *) must_malloc("read_opts packet malloc", COPY_BUFSZ);
 
   optv = read_opts(connection, buf);
   fuse = get_fuse_sock(optv);
@@ -390,10 +336,14 @@ int handle_connection(connection_state * connection) {
   free(buf);
 
   start_reader(connection, fuse);
-  ret = start_writer(connection, fuse);
+  do_write(connection, fuse);
   free(connection);
 
-  return ret;
+  return NULL;
+}
+
+void * handle_connection_thread(void * connection) {
+  return handle_connection((connection_state *) connection);
 }
 
 void toggle_save_trace(int sig) {
@@ -403,15 +353,11 @@ void toggle_save_trace(int sig) {
 void setup_save_trace() {
   save_trace = 0;
   
-  if (SIG_ERR == signal(SIGHUP, toggle_save_trace)) {
-    perror("Couldn't set SIGHUP behavior");
-    exit(1);
-  }
+  if (SIG_ERR == signal(SIGHUP, toggle_save_trace))
+    die(1, "Couldn't set SIGHUP behavior", "");
 
-  if (siginterrupt(SIGHUP, 1)) {
-    perror("Couldn't set siginterrupt for SIGHUP");
-    exit(1);
-  }
+  if (siginterrupt(SIGHUP, 1))
+    die(1, "Couldn't set siginterrupt for SIGHUP", "");
 }
 
 #define ID_LEN 512
@@ -419,11 +365,10 @@ void setup_save_trace() {
 int main(int argc, char * argv[]) {
   int events, read_count;
   char buf[ID_LEN];
-  long conn;
+  long conn_id;
   pthread_t child;
-  void *(*handle)(void *) = (void *(*)(void *)) handle_connection;
   parameters params;
-  connection_state * connection;
+  connection_state * conn;
   char * events_path;
 
   if (argc < 2) {
@@ -432,60 +377,51 @@ int main(int argc, char * argv[]) {
     params.socket9p_root = argv[1];
   }
 
-  if (asprintf(&events_path, "%s/events", params.socket9p_root) == -1) {
-    fprintf(stderr, "Couldn't allocate events path\n");
-    exit(1);
-  }
+  if (asprintf(&events_path, "%s/events", params.socket9p_root) == -1)
+    die(1, "", "Couldn't allocate events path: ");
 
   setup_save_trace();
 
   events = open(events_path, O_RDONLY | O_CLOEXEC);
-  while (events != -1) {
-    read_count = read(events, buf, ID_LEN - 1);
-    if (read_count == -1) {
-      perror("Error reading events path");
-      exit(1);
-    } else if (read_count == 0) {
-      // TODO: this is probably the 9p server's fault due to
-      //       not dropping the read 0 to force short read if
-      //       the real read is flushed
-      fprintf(stderr, "read 0 from event stream\n");
-      continue;
+  if (events != -1) {
+    while (1) {
+      read_count = read(events, buf, ID_LEN - 1);
+      if (read_count == -1) {
+        die(1, "Error reading events path", "");
+      } else if (read_count == 0) {
+        // TODO: this is probably the 9p server's fault due to
+        //       not dropping the read 0 to force short read if
+        //       the real read is flushed
+        fprintf(stderr, "read 0 from event stream\n");
+        continue;
+      }
+
+      buf[read_count] = 0x0;
+
+      errno = 0;
+      conn_id = strtol(buf, NULL, 10);
+      if (errno) die(1, "failed", "Connection id of string '%s'", buf);
+
+      if (debug) fprintf(stderr, "handle connection %ld\n", conn_id);
+
+      conn = (connection_state *) must_malloc("connection state",
+                                              sizeof(connection_state));
+      conn->id = conn_id;
+      conn->params = &params;
+
+      if ((errno = pthread_create(&child, NULL,
+                                  handle_connection_thread, conn)))
+        die(1, "", "Couldn't create thread for connection '%ld': ", conn_id);
+
+      if ((errno = pthread_detach(child)))
+        die(1, "", "Couldn't detach thread for connection '%ld': ", conn_id);
+
+      if (debug) fprintf(stderr, "thread spawned\n");
     }
-
-    buf[read_count] = 0x0;
-
-    errno = 0;
-    conn = strtol(buf, NULL, 10);
-    if (errno) {
-      fprintf(stderr, "connection id of string '%s' ", buf);
-      perror("failed");
-      exit(1);
-    }
-
-    if (debug) fprintf(stderr, "handle connection %ld\n", conn);
-
-    connection = must_malloc("connection state", sizeof(connection_state));
-    connection->id = conn;
-    connection->params = &params;
-
-    if ((errno = pthread_create(&child, NULL, handle, connection))) {
-      fprintf(stderr, "couldn't create thread for connection '%ld' ", conn);
-      perror("");
-      exit(1);
-    }
-
-    if ((errno = pthread_detach(child))) {
-      fprintf(stderr, "couldn't detach thread for connection '%ld' ", conn);
-      perror("");
-      exit(1);
-    }
-
-    if (debug) fprintf(stderr, "thread spawned\n");
   }
 
-  fprintf(stderr, "failed to open events path: %s\n", events_path);
-
+  fprintf(stderr, "Failed to open events path %s: ", events_path);
+  perror("");
   free(events_path);
   return 1;
 }

From c8b9013ed3849859b71aae2d44a5a57fe3ad5858 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Thu, 11 Feb 2016 12:03:46 +0000
Subject: [PATCH 06/17] transfused: use an absolute path for fusermount

Gets rid of non-portable execvpe for execve and prevents diversion.
Explicit diversion will be introduced as a command-line option later.
---
 alpine/packages/transfused/transfused.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 7e398d69d..30699edaf 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -19,9 +19,6 @@ int debug = 0;
 
 int save_trace;
 
-// execvpe is in unistd.h on Linux.
-int execvpe(const char *path, char *const argv[], char *const envp[]);
-
 typedef struct {
   char * socket9p_root;
 } parameters;
@@ -39,7 +36,7 @@ typedef struct {
   int to;
 } copy_thread_state;
 
-char * fusermount = "fusermount";
+char * fusermount = "/bin/fusermount";
 
 void die(int exit_code, const char * perror_arg, const char * fmt, ...) {
   va_list argp;
@@ -237,7 +234,7 @@ int get_fuse_sock(char *const optv[]) {
   // fork and exec fusermount
   fusermount_pid = fork();
   if (!fusermount_pid) // child
-    if (execvpe(fusermount, argv, envp))
+    if (execve(fusermount, argv, envp))
       die(1, "Failed to execute fusermount", "");
 
   // parent

From f949e737e82bd10d70a658457dfcfcdacbb4bfa8 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Thu, 11 Feb 2016 12:04:24 +0000
Subject: [PATCH 07/17] transfused: clean up comma spacing

---
 alpine/packages/transfused/transfused.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 30699edaf..71578e520 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -51,7 +51,7 @@ void * must_malloc(char *const descr, size_t size) {
   void * ptr;
 
   ptr = malloc(size);
-  if (size != 0 && ptr == NULL) die(1,descr,"");
+  if (size != 0 && ptr == NULL) die(1, descr, "");
 
   return ptr;
 }
@@ -65,14 +65,14 @@ char ** read_opts(connection_state * connection, char * buf) {
 
   if (asprintf(&read_path, "%s/connections/%ld/read",
                connection->params->socket9p_root, connection->id) == -1)
-    die(1,"Couldn't allocate read path","");
+    die(1, "Couldn't allocate read path", "");
 
   read_fd = open(read_path, O_RDONLY);
   if (read_fd == -1)
-    die(1,"couldn't open read path", "For connection %ld, ", connection->id);
+    die(1, "couldn't open read path", "For connection %ld, ", connection->id);
 
   read_count = read(read_fd, buf, COPY_BUFSZ - 1);
-  if (read_count == -1) die(1,"read_opts error reading", "");
+  if (read_count == -1) die(1, "read_opts error reading", "");
 
   buf[read_count] = 0x0;
 
@@ -191,7 +191,7 @@ int recv_fd(int sock) {
 
   ret = recvmsg(sock, &msg, 0);
 
-  if (ret == -1) die(1,"recvmsg","");
+  if (ret == -1) die(1, "recvmsg", "");
 
   if (ret > 0 && msg.msg_controllen > 0) {
     cmsg = CMSG_FIRSTHDR(&msg);
@@ -216,7 +216,7 @@ int get_fuse_sock(char *const optv[]) {
   // prepare argv from optv
   for (optc = 0; optv[optc] != NULL; optc++) {}
 
-  argv = (char **) must_malloc("fusermount argv",(optc + 2) * sizeof(char *));
+  argv = (char **) must_malloc("fusermount argv", (optc + 2) * sizeof(char *));
 
   argv[0] = fusermount;
   memcpy(&argv[1], optv, (optc + 1) * sizeof(char *));

From 2fec071a41da4425ae04b1832dc009f1ead5e12e Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Thu, 11 Feb 2016 12:06:32 +0000
Subject: [PATCH 08/17] transfused: clean up equal sign spacing

---
 alpine/packages/transfused/transfused.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 71578e520..cb94efac3 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -178,13 +178,13 @@ int recv_fd(int sock) {
   struct iovec vec;
   struct cmsghdr *cmsg;
 
-  msg.msg_name=NULL;
-  msg.msg_namelen=0;
-  vec.iov_base=&iochar;
-  vec.iov_len=1;
-  msg.msg_iov=&vec;
+  msg.msg_name = NULL;
+  msg.msg_namelen = 0;
+  vec.iov_base = &iochar;
+  vec.iov_len = 1;
+  msg.msg_iov = &vec;
 
-  msg.msg_iovlen=1;
+  msg.msg_iovlen = 1;
 
   msg.msg_control = buf;
   msg.msg_controllen = sizeof(buf);

From fee789baf1f5ae47701bde5330cc2acfe2de702c Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Thu, 11 Feb 2016 12:09:30 +0000
Subject: [PATCH 09/17] transfused: hook debug into HUP-toggled run-time debug
 system

---
 alpine/packages/transfused/transfused.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index cb94efac3..fe1d20c05 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -17,8 +17,6 @@
 
 int debug = 0;
 
-int save_trace;
-
 typedef struct {
   char * socket9p_root;
 } parameters;
@@ -116,7 +114,7 @@ void copy(copy_thread_state * copy_state) {
     read_count = read(from, buf, COPY_BUFSZ);
     if (read_count == -1) die(1, "", "copy %s: error reading: ", descr);
 
-    if (save_trace) {
+    if (debug) {
       int trace_fd;
       char * trace_path;
 
@@ -343,14 +341,12 @@ void * handle_connection_thread(void * connection) {
   return handle_connection((connection_state *) connection);
 }
 
-void toggle_save_trace(int sig) {
-  save_trace = !save_trace;
+void toggle_debug(int sig) {
+  debug = !debug;
 }
 
-void setup_save_trace() {
-  save_trace = 0;
-  
-  if (SIG_ERR == signal(SIGHUP, toggle_save_trace))
+void setup_debug() {
+  if (SIG_ERR == signal(SIGHUP, toggle_debug))
     die(1, "Couldn't set SIGHUP behavior", "");
 
   if (siginterrupt(SIGHUP, 1))
@@ -377,7 +373,7 @@ int main(int argc, char * argv[]) {
   if (asprintf(&events_path, "%s/events", params.socket9p_root) == -1)
     die(1, "", "Couldn't allocate events path: ");
 
-  setup_save_trace();
+  setup_debug();
 
   events = open(events_path, O_RDONLY | O_CLOEXEC);
   if (events != -1) {

From 71fa8711ec170992e655a5ede97a63983ecdf769 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Thu, 11 Feb 2016 12:11:04 +0000
Subject: [PATCH 10/17] transfused: do not check return of close

on advice from @justincormack
---
 alpine/packages/transfused/transfused.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index fe1d20c05..90b7df2ff 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -141,8 +141,7 @@ void copy(copy_thread_state * copy_state) {
 void * copy_clean_from(copy_thread_state * copy_state) {
   copy(copy_state);
 
-  if (close(copy_state->from))
-    die(1, "couldn't close read fd", "For %s, ", copy_state->descr);
+  close(copy_state->from);
 
   free(copy_state->descr);
   free(copy_state);
@@ -157,8 +156,7 @@ void * copy_clean_from_thread(void * copy_state) {
 void * copy_clean_to(copy_thread_state * copy_state) {
   copy(copy_state);
 
-  if (close(copy_state->to))
-    die(1, "couldn't close write fd", "For %s, ", copy_state->descr);
+  close(copy_state->to);
 
   free(copy_state->descr);
   free(copy_state);
@@ -240,8 +238,7 @@ int get_fuse_sock(char *const optv[]) {
   free(envp[0]);
 
   // close the end of the socket that we gave away
-  if (close(fuse_socks[0]))
-    die(1, "Couldn't close unneeded fusermount socket", "");
+  close(fuse_socks[0]);
 
   // wait for fusermount to return
   waitpid(fusermount_pid, &status, 0);
@@ -258,8 +255,7 @@ int get_fuse_sock(char *const optv[]) {
     die(1, NULL, "Couldn't receive fd over FUSE socket\n");
 
   // close the read end of the socket
-  if (close(fuse_socks[1]))
-    die(1, "Couldn't close fusermount read socket", "");
+  close(fuse_socks[1]);
 
   return fd;
 }

From c830c223355299aa2a4744b686875806d477b4d7 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Thu, 11 Feb 2016 15:14:54 +0000
Subject: [PATCH 11/17] transfused: add trace logging error checking

---
 alpine/packages/transfused/transfused.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 90b7df2ff..e2da46623 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -118,11 +118,22 @@ void copy(copy_thread_state * copy_state) {
       int trace_fd;
       char * trace_path;
 
-      // TODO: check for errors
-      asprintf(&trace_path, "/tmp/transfused.%ld.%s.%llu",
-               connection, tag, message_id(buf));
+      if (asprintf(&trace_path, "/tmp/transfused.%ld.%s.%llu",
+                   connection, tag, message_id(buf)) == -1)
+        die(1, "", "Couldn't allocate trace packet path");
+
       trace_fd = open(trace_path, O_WRONLY | O_CREAT, 0600);
-      write(trace_fd, buf, read_count);
+      if (read_fd == -1)
+        die(1, "couldn't open trace packet path", "For %s, ", descr);
+
+      write_count = write(trace_fd, buf, read_count);
+      if (write_count == -1)
+        die(1, "", "copy %s trace: error writing %s: ", descr, trace_path);
+
+      if (write_count != read_count)
+        die(1, NULL, "copy %s trace: read %d but only write %d\n",
+            descr, read_count, write_count);
+
       close(trace_fd);
       free(trace_path);
     }

From d69b402584296529aba2cb436805dcbf69cb2fa0 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Fri, 12 Feb 2016 11:00:09 +0000
Subject: [PATCH 12/17] transfused: improve some error message output and fix
 an fd mixup

---
 alpine/packages/transfused/transfused.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index e2da46623..84b9cab20 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -120,10 +120,10 @@ void copy(copy_thread_state * copy_state) {
 
       if (asprintf(&trace_path, "/tmp/transfused.%ld.%s.%llu",
                    connection, tag, message_id(buf)) == -1)
-        die(1, "", "Couldn't allocate trace packet path");
+        die(1, "Couldn't allocate trace packet path", "");
 
       trace_fd = open(trace_path, O_WRONLY | O_CREAT, 0600);
-      if (read_fd == -1)
+      if (trace_fd == -1)
         die(1, "couldn't open trace packet path", "For %s, ", descr);
 
       write_count = write(trace_fd, buf, read_count);
@@ -234,7 +234,7 @@ int get_fuse_sock(char *const optv[]) {
 
   // prepare to exec the suid binary fusermount
   if (asprintf(&envp[0], "_FUSE_COMMFD=%d", fuse_socks[0]) == -1)
-    die(1, "", "Couldn't allocate fusermount envp");
+    die(1, "Couldn't allocate fusermount envp", "");
 
   envp[1] = 0x0;
 
@@ -279,7 +279,7 @@ void start_reader(connection_state * connection, int fuse) {
 
   if (asprintf(&read_path, "%s/connections/%ld/read",
                connection->params->socket9p_root, connection->id) == -1)
-    die(1, "", "Couldn't allocate read path: ");
+    die(1, "Couldn't allocate read path", "");
 
   read_fd = open(read_path, O_RDONLY);
   if (read_fd == -1)
@@ -309,7 +309,7 @@ void do_write(connection_state * connection, int fuse) {
 
   if (asprintf(&write_path, "%s/connections/%ld/write",
                connection->params->socket9p_root, connection->id) == -1)
-    die(1, "", "Couldn't allocate write path: ");
+    die(1, "Couldn't allocate write path", "");
 
   write_fd = open(write_path, O_WRONLY);
   if (write_fd == -1)
@@ -387,12 +387,12 @@ int main(int argc, char * argv[]) {
     while (1) {
       read_count = read(events, buf, ID_LEN - 1);
       if (read_count == -1) {
-        die(1, "Error reading events path", "");
+        die(1, "", "Error reading events path %s: ", events_path);
       } else if (read_count == 0) {
         // TODO: this is probably the 9p server's fault due to
         //       not dropping the read 0 to force short read if
         //       the real read is flushed
-        fprintf(stderr, "read 0 from event stream\n");
+        fprintf(stderr, "read 0 from event stream %s\n", events_path);
         continue;
       }
 

From 94c3143c76de437262a2a4488b6d70a02d6b1640 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Fri, 12 Feb 2016 11:03:47 +0000
Subject: [PATCH 13/17] transfused: introduce command line arguments for
 pidfile, fusermount, 9p

---
 alpine/packages/transfused/transfused.c | 144 ++++++++++++++++++++----
 1 file changed, 120 insertions(+), 24 deletions(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 84b9cab20..412d71b00 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -15,10 +15,23 @@
 
 #define COPY_BUFSZ 65536
 
+#define DEFAULT_FUSERMOUNT "/bin/fusermount"
+#define DEFAULT_SOCKET9P_ROOT "/Transfused"
+
+char * default_fusermount = DEFAULT_FUSERMOUNT;
+char * default_socket9p_root = DEFAULT_SOCKET9P_ROOT;
+char * usage =
+  "usage: transfused [-p pidfile] [-9 socket9p_root] [-f fusermount]\n"
+  " -p pidfile\tthe path at which to write the pid of the process\n"
+  " -9 " DEFAULT_SOCKET9P_ROOT "\tthe root of the 9p socket file system\n"
+  " -f " DEFAULT_FUSERMOUNT "\tthe fusermount executable to use\n";
+
 int debug = 0;
 
 typedef struct {
   char * socket9p_root;
+  char * fusermount;
+  char * pidfile;
 } parameters;
 
 typedef struct {
@@ -34,8 +47,6 @@ typedef struct {
   int to;
 } copy_thread_state;
 
-char * fusermount = "/bin/fusermount";
-
 void die(int exit_code, const char * perror_arg, const char * fmt, ...) {
   va_list argp;
   va_start(argp, fmt);
@@ -211,7 +222,7 @@ int recv_fd(int sock) {
 }
 
 // optv must be null-terminated
-int get_fuse_sock(char *const optv[]) {
+int get_fuse_sock(char * fusermount, char *const optv[]) {
   int optc;
   char ** argv;
   char * envp[2];
@@ -333,7 +344,7 @@ void * handle_connection(connection_state * connection) {
   buf = (char *) must_malloc("read_opts packet malloc", COPY_BUFSZ);
 
   optv = read_opts(connection, buf);
-  fuse = get_fuse_sock(optv);
+  fuse = get_fuse_sock(connection->params->fusermount, optv);
   free(optv);
   free(buf);
 
@@ -360,30 +371,99 @@ void setup_debug() {
     die(1, "Couldn't set siginterrupt for SIGHUP", "");
 }
 
-#define ID_LEN 512
+void parse_parameters(int argc, char * argv[], parameters * params) {
+  int c;
+  int errflg = 0;
 
-int main(int argc, char * argv[]) {
-  int events, read_count;
-  char buf[ID_LEN];
-  long conn_id;
-  pthread_t child;
-  parameters params;
-  connection_state * conn;
-  char * events_path;
+  params->pidfile = NULL;
+  params->socket9p_root = NULL;
+  params->fusermount = NULL;
 
-  if (argc < 2) {
-    params.socket9p_root = "/Transfuse";
-  } else {
-    params.socket9p_root = argv[1];
+  while ((c = getopt(argc, argv, ":p:9:f:")) != -1) {
+    switch(c) {
+
+    case 'p':
+      params->pidfile = optarg;
+      break;
+
+    case '9':
+      params->socket9p_root = optarg;
+      break;
+
+    case 'f':
+      params->fusermount = optarg;
+      break;
+
+    case ':':
+      fprintf(stderr, "Option -%c requires a path argument\n", optopt);
+      errflg++;
+      break;
+
+    case '?':
+      fprintf(stderr, "Unrecognized option: '-%c'\n", optopt);
+      errflg++;
+      break;
+
+    default:
+      fprintf(stderr, "Internal error parsing -%c\n", c);
+      errflg++;
+    }
   }
 
-  if (asprintf(&events_path, "%s/events", params.socket9p_root) == -1)
-    die(1, "", "Couldn't allocate events path: ");
+  if (errflg) die(2, NULL, usage);
 
-  setup_debug();
+  if (params->pidfile != NULL && access(params->pidfile, W_OK))
+    die(2, "", "-p %s path to pidfile must be writable: ", params->pidfile);
+
+  if (params->fusermount == NULL)
+    params->fusermount = default_fusermount;
+  if (access(params->fusermount, X_OK))
+    die(2, "", "-f %s path to fusermount must be executable: ",
+        params->fusermount);
+
+  if (params->socket9p_root == NULL)
+    params->socket9p_root = default_socket9p_root;
+  if (access(params->socket9p_root, X_OK))
+    die(2, "", "-9 %s path to socket 9p root directory must be executable: ",
+        params->socket9p_root);
+}
+
+void write_pidfile(char * pidfile) {
+  int fd;
+  pid_t pid = getpid();
+  char * pid_s;
+  int pid_s_len, write_count;
+
+  if (asprintf(&pid_s, "%lld", (long long) pid) == -1)
+    die(1, "Couldn't allocate pidfile string", "");
+
+  pid_s_len = strlen(pid_s);
+
+  fd = open(pidfile, O_WRONLY | O_CREAT, 0644);
+  if (fd == -1)
+    die(1, "", "Couldn't open pidfile path %s: ", pidfile);
+
+  write_count = write(fd, pid_s, pid_s_len);
+  if (write_count == -1)
+    die(1, "", "Error writing pidfile %s: ", pidfile);
+
+  if (write_count != pid_s_len)
+    die(1, NULL, "Error writing %s to pidfile %s: only wrote %d bytes\n",
+        pid_s, pidfile, write_count);
+
+  close(fd);
+  free(pid_s);
+}
+
+#define ID_LEN 512
+
+void process_events(char * events_path, int events, parameters * params) {
+    char buf[ID_LEN];
+    int read_count;
+    long conn_id;
+    pthread_t child;
+    connection_state * conn;
 
-  events = open(events_path, O_RDONLY | O_CLOEXEC);
-  if (events != -1) {
     while (1) {
       read_count = read(events, buf, ID_LEN - 1);
       if (read_count == -1) {
@@ -407,7 +487,7 @@ int main(int argc, char * argv[]) {
       conn = (connection_state *) must_malloc("connection state",
                                               sizeof(connection_state));
       conn->id = conn_id;
-      conn->params = &params;
+      conn->params = params;
 
       if ((errno = pthread_create(&child, NULL,
                                   handle_connection_thread, conn)))
@@ -418,7 +498,23 @@ int main(int argc, char * argv[]) {
 
       if (debug) fprintf(stderr, "thread spawned\n");
     }
-  }
+}
+
+int main(int argc, char * argv[]) {
+  int events;
+  parameters params;
+  char * events_path;
+
+  parse_parameters(argc, argv, &params);
+  setup_debug();
+
+  if (params.pidfile != NULL) write_pidfile(params.pidfile);
+
+  if (asprintf(&events_path, "%s/events", params.socket9p_root) == -1)
+    die(1, "Couldn't allocate events path", "");
+
+  events = open(events_path, O_RDONLY | O_CLOEXEC);
+  if (events != -1) process_events(events_path, events, &params);
 
   fprintf(stderr, "Failed to open events path %s: ", events_path);
   perror("");

From 7f088f90085590361afb5455bfdde693374e3cf1 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Fri, 12 Feb 2016 11:35:39 +0000
Subject: [PATCH 14/17] transfused: fix the 9p socket root name

---
 alpine/packages/transfused/transfused.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 412d71b00..4361bffb4 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -16,7 +16,7 @@
 #define COPY_BUFSZ 65536
 
 #define DEFAULT_FUSERMOUNT "/bin/fusermount"
-#define DEFAULT_SOCKET9P_ROOT "/Transfused"
+#define DEFAULT_SOCKET9P_ROOT "/Transfuse"
 
 char * default_fusermount = DEFAULT_FUSERMOUNT;
 char * default_socket9p_root = DEFAULT_SOCKET9P_ROOT;

From eb199ca9d74bad7862a90da97d9fb718cbc9d096 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Fri, 12 Feb 2016 11:40:26 +0000
Subject: [PATCH 15/17] transfused: init with a pidfile

---
 alpine/packages/transfused/etc/init.d/transfused | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/alpine/packages/transfused/etc/init.d/transfused b/alpine/packages/transfused/etc/init.d/transfused
index 06ee22a3b..dd8ff212f 100755
--- a/alpine/packages/transfused/etc/init.d/transfused
+++ b/alpine/packages/transfused/etc/init.d/transfused
@@ -15,7 +15,7 @@ start()
 
 	[ -n "${PIDFILE}" ] || PIDFILE=/var/run/transfused.pid
 
-        /sbin/transfused &
+        /sbin/transfused -p "${PIDFILE}" &
 }
 
 stop()

From cbd5ca599117997671b219a103aa24ce7e0a6537 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Fri, 12 Feb 2016 11:46:18 +0000
Subject: [PATCH 16/17] transfused: it is ok if the pidfile does not yet exist

---
 alpine/packages/transfused/transfused.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 4361bffb4..54d1cee2f 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -413,7 +413,8 @@ void parse_parameters(int argc, char * argv[], parameters * params) {
   if (errflg) die(2, NULL, usage);
 
   if (params->pidfile != NULL && access(params->pidfile, W_OK))
-    die(2, "", "-p %s path to pidfile must be writable: ", params->pidfile);
+    if (errno != ENOENT)
+      die(2, "", "-p %s path to pidfile must be writable: ", params->pidfile);
 
   if (params->fusermount == NULL)
     params->fusermount = default_fusermount;

From b1d310184625756db663e8cf375d0a0b5b7ba839 Mon Sep 17 00:00:00 2001
From: David Sheets <sheets@alum.mit.edu>
Date: Fri, 12 Feb 2016 11:46:44 +0000
Subject: [PATCH 17/17] transfused: if the pidfile exists, make sure to
 truncate it

---
 alpine/packages/transfused/transfused.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/alpine/packages/transfused/transfused.c b/alpine/packages/transfused/transfused.c
index 54d1cee2f..5179d4af1 100644
--- a/alpine/packages/transfused/transfused.c
+++ b/alpine/packages/transfused/transfused.c
@@ -440,7 +440,7 @@ void write_pidfile(char * pidfile) {
 
   pid_s_len = strlen(pid_s);
 
-  fd = open(pidfile, O_WRONLY | O_CREAT, 0644);
+  fd = open(pidfile, O_WRONLY | O_CREAT | O_TRUNC, 0644);
   if (fd == -1)
     die(1, "", "Couldn't open pidfile path %s: ", pidfile);