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dom0/qrexec: properly process data after client terminated one way of transfer

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Instead of removing client from list at EPIPE error from write, assume that
client does not wish read future data, but still can write something.
This commit is contained in:
Marek Marczykowski 2012-08-27 00:49:45 +02:00
parent f79101d114
commit 3bce6047b5
2 changed files with 43 additions and 8 deletions
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20
qrexec/qrexec_client.c
View File

@ -116,8 +116,24 @@ void handle_input(int s)
}
}
if (!write_all(s, buf, ret)) {
perror("write daemon");
do_exit(1);
if (errno == EPIPE) {
// daemon disconnected its end of socket, so no future data will be
// send there; there is no sense to read from child stdout
//
// since AF_UNIX socket is buffered it doesn't mean all data was
// received from the agent
close(local_stdout_fd);
local_stdout_fd = -1;
if (local_stdin_fd == -1) {
// since child does no longer accept data on its stdin, doesn't
// make sense to process the data from the daemon
//
// we don't know real exit VM process code (exiting here, before
// MSG_SERVER_TO_CLIENT_EXIT_CODE message)
do_exit(1);
}
} else
perror("write daemon");
}
}

31
qrexec/qrexec_daemon.c
View File

@ -38,8 +38,10 @@ enum client_flags {
CLIENT_INVALID = 0, // table slot not used
CLIENT_CMDLINE = 1, // waiting for cmdline from client
CLIENT_DATA = 2, // waiting for data from client
CLIENT_DONT_READ = 4, // don't read from the client, the other side pipe is full, or EOF
CLIENT_OUTQ_FULL = 8 // don't write to client, its stdin pipe is full
CLIENT_DONT_READ = 4, // don't read from the client, the other side pipe is full, or EOF (additionally marked with CLIENT_EOF)
CLIENT_OUTQ_FULL = 8, // don't write to client, its stdin pipe is full
CLIENT_EOF = 16, // got EOF
CLIENT_EXITED = 32 // only send remaining data from client and remove from list
};
struct _client {
@ -170,7 +172,7 @@ void terminate_client_and_flush_data(int fd)
int i;
struct server_header s_hdr;
if (fork_and_flush_stdin(fd, &clients[fd].buffer))
if (!(clients[fd].state & CLIENT_EXITED) && fork_and_flush_stdin(fd, &clients[fd].buffer))
children_count++;
close(fd);
clients[fd].state = CLIENT_INVALID;
@ -266,7 +268,10 @@ void handle_message_from_client(int fd)
write_all_vchan_ext(&s_hdr, sizeof(s_hdr));
write_all_vchan_ext(buf, ret);
if (ret == 0) // EOF - so don't select() on this client
clients[fd].state |= CLIENT_DONT_READ;
clients[fd].state |= CLIENT_DONT_READ | CLIENT_EOF;
if (clients[fd].state & CLIENT_EXITED)
//client already exited and all data sent - cleanup now
terminate_client_and_flush_data(fd);
}
/*
@ -282,7 +287,14 @@ void write_buffered_data_to_client(int client_id)
clients[client_id].state &= ~CLIENT_OUTQ_FULL;
break;
case WRITE_STDIN_ERROR:
terminate_client_and_flush_data(client_id);
// do not write to this fd anymore
clients[client_id].state |= CLIENT_EXITED;
if (clients[client_id].state & CLIENT_EOF)
terminate_client_and_flush_data(client_id);
else
// client will be removed when read returns 0 (EOF)
// clear CLIENT_OUTQ_FULL flag to no select on this fd anymore
clients[client_id].state &= ~CLIENT_OUTQ_FULL;
break;
case WRITE_STDIN_BUFFERED: // no room for all data, don't clear CLIENT_OUTQ_FULL flag
break;
@ -305,6 +317,9 @@ void get_packet_data_from_agent_and_pass_to_client(int client_id, struct client_
/* make both the header and data be consecutive in the buffer */
*(struct client_header *) buf = *hdr;
read_all_vchan_ext(buf + sizeof(*hdr), len);
if (clients[client_id].state & CLIENT_EXITED)
// ignore data for no longer running client
return;
switch (write_stdin
(client_id, client_id, buf, len + sizeof(*hdr),
@ -315,7 +330,11 @@ void get_packet_data_from_agent_and_pass_to_client(int client_id, struct client_
clients[client_id].state |= CLIENT_OUTQ_FULL;
break;
case WRITE_STDIN_ERROR:
terminate_client_and_flush_data(client_id);
// do not write to this fd anymore
clients[client_id].state |= CLIENT_EXITED;
// if already got EOF, remove client
if (clients[client_id].state & CLIENT_EOF)
terminate_client_and_flush_data(client_id);
break;
default:
fprintf(stderr, "unknown write_stdin?\n");