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The forked agent doesn't work yet. Either I've misunderstood fork()
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or it has weird semantics on cygwin. Oh well, check it in, *then*
figure it out.
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@wesleyd
wesleyd committed Nov 23, 2009
1 parent a782c78 commit 6283aec
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Showing 3 changed files with 99 additions and 87 deletions.
2 changes: 2 additions & 0 deletions TODO
View file
Expand Up @@ -7,3 +7,5 @@ o Deal with partial messages from ssh - unlikely, but catastrophic!
+ Look at length at beginning, block until length arrives.
o Check open files in each process that results
o Signal handling
o Specified agent socket
o Redirect stderr (& stdout?) to log even 'pon fork
176 changes: 89 additions & 87 deletions charade.c
View file
Expand Up @@ -22,6 +22,7 @@

#include "cmdline.h"
#include "eprintf.h"
#include "todo.h"

#define LISTEN_BACKLOG 5
#define BUFSIZE 8192
Expand Down Expand Up @@ -122,10 +123,6 @@ remove_socket(void) /* atexit handler */
void
create_socket(void)
{
#if 0
if (agentsocket == NULL) {
#endif

if (atexit(remove_socket_dir)) {
EPRINTF(0, "Can't install atexit handler to delete socket dir.\n");
exit(1);
Expand All @@ -134,9 +131,8 @@ create_socket(void)
/* Create private directory for agent socket */
strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
if (mkdtemp(socket_dir) == NULL) {
EPRINTF(0, "Can't mkdir private socket directory: %s\n",
EPRINTF(0, "Can't mkdir socket directory: %s\n",
strerror(errno));
//perror("mkdtemp: private socket dir");
exit(1);
}

Expand All @@ -146,24 +142,14 @@ create_socket(void)
"%s/agent.%ld", socket_dir, (long)getpid());
if (ret >= sizeof(socket_name)) {
// Would have liked to print more...
fprintf(stderr, "socket_name too long (%d >= %d).\n",
EPRINTF(0, "socket_name too long (%d >= %d).\n",
ret, sizeof(socket_name));
exit(1);
}


#if 0
} else {
/* Try to use specified agent socket */
socket_dir[0] = '\0';
strlcpy(socket_name, agentsocket, sizeof socket_name);
}
#endif


listen_sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (listen_sock < 0) {
perror("socket");
EPRINTF(0, "socket error: %s.\n", strerror(errno));
exit(1);
}

Expand All @@ -173,20 +159,20 @@ create_socket(void)
strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
int prev_mask = umask(0177);
if (bind(listen_sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
perror("bind");
EPRINTF(0, "bind() error: %s.\n", strerror(errno));
umask(prev_mask);
exit(1);
}

if (atexit(remove_socket)) {
fprintf(stderr, "Can't install atexit handler to delete socket '%s'. "
"Do it yourself!\n", socket_name);
EPRINTF(0, "Can't install atexit handler to delete socket '%s'; "
"do it yourself!\n", socket_name);
exit(1);
}

umask(prev_mask);
if (listen(listen_sock, LISTEN_BACKLOG) < 0) {
perror("listen");
EPRINTF(0, "listen() error: %s", strerror(errno));
exit(1);
}
}
Expand Down Expand Up @@ -250,42 +236,6 @@ print_env_stuff(int pid)
print_env_var(SSH_AGENTPID_ENV_NAME, itoa_unsafe(pid));
}

void
fork_subprocess(void)
{
if (! g_dontfork_flag) {
long pid = fork();

if (-1 == pid) {
perror("fork");
exit(1);
}

if (pid) { // Parent
printf("%s=%s; export %s\n", SSH_AUTHSOCKET_ENV_NAME, socket_name,
SSH_AUTHSOCKET_ENV_NAME);
printf("%s=%ld; export %s\n", SSH_AGENTPID_ENV_NAME, (long) pid,
SSH_AGENTPID_ENV_NAME);

// TODO: If argv present, fork and exec it. Only do above if no args.

remove_socket_at_exit = 0;
exit(0);
}
// Child
if (setsid() == -1) {
perror("setsid");
}
} else {
int pid = getpid();

printf("%s=%s; export %s\n", SSH_AUTHSOCKET_ENV_NAME, socket_name,
SSH_AUTHSOCKET_ENV_NAME);
printf("%s=%ld; export %s\n", SSH_AGENTPID_ENV_NAME, (long) pid,
SSH_AGENTPID_ENV_NAME);
}
}

int
make_poll_fds(struct pollfd **fds)
{
Expand All @@ -295,7 +245,7 @@ make_poll_fds(struct pollfd **fds)
struct pollfd *pollfds = calloc(sizeof(struct pollfd), nfds);

if (!pollfds) {
fprintf(stderr, "Can't calloc struct pollfd's for poll().\n");
EPRINTF(0, "Can't calloc() %d struct pollfd's for poll().\n", nfds);
exit(1);
}

Expand All @@ -307,14 +257,15 @@ make_poll_fds(struct pollfd **fds)
for (p = socklist.tqh_first; p != NULL; p = p->next.tqe_next) {

if (i >= nfds) {
fprintf(stderr, "Fatal: socket list changed underneath us.\n");
EPRINTF(0, "Internal error: socket list changed beneath us.\n");
exit(1);
}

// TODO: Do we want POLLOUT and the close notifications too???

pollfds[i].events = POLLIN | POLLHUP;
pollfds[i].fd = p->fd;
++i;
}

*fds = pollfds;
Expand All @@ -332,15 +283,14 @@ set_nonblock(int sock)
{
int flags = fcntl(sock, F_GETFL, 0);
if (flags < 0) {
fprintf(stderr, "fcntl(%d, F_GETFL, 0): %s.\n", sock, strerror(errno));
EPRINTF(0, "Can't fcntl(%d, F_GETFL, 0): %s.\n", sock, strerror(errno));
exit(1);
}

flags |= O_NONBLOCK;

if (fcntl(sock, F_SETFL, flags) == -1) {
fprintf(stderr, "fcntl(%d, F_SETFL, O_NONBLOCK): %s.\n",
sock, strerror(errno));
EPRINTF(0, "fcntl(%d, F_SETFL, O_NONBLOCK): %s.\n", sock, strerror(errno));
exit(1);
}
}
Expand All @@ -353,7 +303,7 @@ accept_new_socket(void)
int newsock = accept(listen_sock, (struct sockaddr *) &sunaddr, &socksize);

if (-1 == newsock) {
perror("accept");
EPRINTF(0, "accept error: %s", strerror(errno));
exit(1);
}

Expand All @@ -365,9 +315,10 @@ accept_new_socket(void)
void
fd_is_closed(int fd)
{
EPRINTF(3, "Removing fd %d from list.\n", fd);
// Remove it from the list...

// TODO: Remove the fd from the big list!
// Remove the fd from the list...
struct socklist_node_t *p;
for (p = socklist.tqh_first; p != NULL; p = p->next.tqe_next) {
if (p->fd == fd) {
Expand All @@ -385,6 +336,8 @@ fd_is_closed(int fd)
int
send_request_to_pageant(byte *buf, int numbytes, int bufsize)
{
EPRINTF(3, "Sending %d bytes to pageant.\n", numbytes);

// Now, let's just *assume* that it'll arrive in one big
// chunk and just *send* it to pageant...
HWND hwnd;
Expand All @@ -406,8 +359,8 @@ send_request_to_pageant(byte *buf, int numbytes, int bufsize)
return 0;
}

byte *p = MapViewOfFile(filemap, FILE_MAP_WRITE, 0, 0, 0);
memcpy(p, buf, numbytes);
byte *shmem = MapViewOfFile(filemap, FILE_MAP_WRITE, 0, 0, 0);
memcpy(shmem, buf, numbytes);
COPYDATASTRUCT cds;
cds.dwData = AGENT_COPYDATA_ID;
cds.cbData = 1 + strlen(mapname);
Expand All @@ -416,22 +369,23 @@ send_request_to_pageant(byte *buf, int numbytes, int bufsize)
int id = SendMessage(hwnd, WM_COPYDATA, (WPARAM) NULL, (LPARAM) &cds);
int retlen = 0;
if (id > 0) {
retlen = 4 + GET_32BIT(p);
retlen = 4 + GET_32BIT(shmem);
if (retlen > bufsize) {
EPRINTF(0, "Buffer too small to contain reply from pageant.\n");
return 0;
}

// TODO: are there miscounting errors here?

memcpy(buf, p, retlen);
memcpy(buf, shmem, retlen);
} else {
EPRINTF(0, "Couldn't SendMessage().\n");
return 0;
}
UnmapViewOfFile(p);

UnmapViewOfFile(shmem);
CloseHandle(filemap);

EPRINTF(3, "Got %d bytes back from pageant.\n", retlen);

return retlen;
}

Expand All @@ -448,38 +402,50 @@ deal_with_ready_fds(struct pollfd *fds, int nfds)
// Don't just *assume* that entry 0 is listen_sock...
if (listen_sock == fds[i].fd) {
accept_new_socket();
} else {
} else if (fds[i].revents & POLLIN) {
// Deal with data from fds[i].fd...
const size_t count = BUFSIZE;
byte buf[BUFSIZE];

ssize_t numbytes = read(fds[i].fd, buf, count);

if (0 == numbytes) {
close(fds[i].fd);
fd_is_closed(fds[i].fd);
} else if (-1 == numbytes) {
fprintf(stderr, "TODO: fd %d error, errno is %s.\n", fds[i].fd, strerror(errno));
exit(1);
// TODO: Should we handle EAGAIN/EWOULDBLOCK specially?
EPRINTF(0, "internal error: read(fd=%d) => errno=%d/%s.\n",
fds[i].fd, errno, strerror(errno));
close(fds[i].fd);
fd_is_closed(fds[i].fd);
} else {
int retlen = send_request_to_pageant(buf, numbytes, sizeof(buf));

// Now, send buf back to the socket. We should probably
// loop and retry or use poll properly since it's nonblocking...
ssize_t byteswritten = write(fds[i].fd, buf, retlen);
if (byteswritten != retlen) {
fprintf(stderr, "Tried to write %d bytes, "
"ended up writing %d. Quitting.\n",
EPRINTF(0, "Tried to write %d bytes, "
"ended up writing %d.\n",
retlen, byteswritten);
exit(1);
close(fds[i].fd);
fd_is_closed(fds[i].fd);
}
}
}
} else {
EPRINTF(0, "Don't know how to deal with revents=0x%x on fd %d.\n",
fds[i].revents, fds[i].fd);
close(fds[i].fd);
fd_is_closed(fds[i].fd);
}
}
}

void
handle_key_requests_forever(void)
{
EPRINTF(5, "entry.\n");

for (;;) {
struct pollfd *fds;
int nfds = make_poll_fds(&fds);
Expand All @@ -493,11 +459,11 @@ handle_key_requests_forever(void)
EPRINTF(3, "poll() was EINTR-ed.\n");
continue;
} else {
perror("poll error");
EPRINTF(0, "poll error: %s.\n", strerror(errno));
exit(1);
}
} else if (0 == numready) {
fprintf(stderr, "Error: poll() => 0, but no timeout was set.\n");
EPRINTF(0, "Internal error: poll() => 0, but no timeout was set.\n");
exit(1);
}

Expand All @@ -508,15 +474,49 @@ handle_key_requests_forever(void)
pid_t
fork_off_key_handler(void)
{
fprintf(stderr, "TODO: fork_off_key_handler.\n");
exit(1);
pid_t handler_pid = fork();
if (handler_pid == -1) {
EPRINTF(0, "Can't fork(): %s.\n", strerror(errno));
exit(1);
}

if (handler_pid != 0) {
return handler_pid;
}

// OK, we're the child agent process now...

FILE *f = fopen("/tmp/loggy", "w");

fprintf(f, "Hello.\n");
fflush(f);

// TODO: Do the setsid thing
/*
if (setsid() == -1) {
EPRINTF(0, "error from setsid(): %s.\n", strerror(errno));
exit(1);
}
*/

chdir("/");

// TODO: Do the filehandle thing

// TODO: Do setrlimit thing

// TODO: Do the signal thing

handle_key_requests_forever();

/* NOTREACHED */
exit(0);
}

void
exec_subprocess(void)
exec_subprocess(pid_t agent_pid)
{
fprintf(stderr, "TODO: exec_subprocess.\n");
exit(1);
TODO();
}

int
Expand Down Expand Up @@ -544,8 +544,10 @@ main(int argc, char **argv)
} else {
pid_t agent_pid = fork_off_key_handler();

close(listen_sock);

if (g_subprocess_argc) {
exec_subprocess();
exec_subprocess(agent_pid);
/* NOTREACHED */
} else {
print_env_stuff(agent_pid);
Expand Down
8 changes: 8 additions & 0 deletions todo.h
View file
@@ -0,0 +1,8 @@
#ifndef TODO_H
#define TODO_H

#include "eprintf.h"

#define TODO() do { EPRINTF(0, "TODO.\n"); exit(1); } while (1)

#endif // #ifndef TODO_H

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