| /* Serial interface for raw TCP connections on Un*x like systems. |
| |
| Copyright (C) 1992-2021 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| #include "serial.h" |
| #include "ser-base.h" |
| #include "ser-tcp.h" |
| #include "gdbcmd.h" |
| #include "cli/cli-decode.h" |
| #include "cli/cli-setshow.h" |
| #include "gdbsupport/filestuff.h" |
| #include "gdbsupport/netstuff.h" |
| |
| #include <sys/types.h> |
| |
| #ifdef HAVE_SYS_FILIO_H |
| #include <sys/filio.h> /* For FIONBIO. */ |
| #endif |
| #ifdef HAVE_SYS_IOCTL_H |
| #include <sys/ioctl.h> /* For FIONBIO. */ |
| #endif |
| |
| #include "gdbsupport/gdb_sys_time.h" |
| |
| #ifdef USE_WIN32API |
| #include <ws2tcpip.h> |
| #ifndef ETIMEDOUT |
| #define ETIMEDOUT WSAETIMEDOUT |
| #endif |
| /* Gnulib defines close too, but gnulib's replacement |
| doesn't call closesocket unless we import the |
| socketlib module. */ |
| #undef close |
| #define close(fd) closesocket (fd) |
| #define ioctl ioctlsocket |
| #else |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| #include <netdb.h> |
| #include <sys/socket.h> |
| #include <netinet/tcp.h> |
| #endif |
| |
| #include <signal.h> |
| #include "gdbsupport/gdb_select.h" |
| #include <algorithm> |
| |
| #ifndef HAVE_SOCKLEN_T |
| typedef int socklen_t; |
| #endif |
| |
| /* For "set tcp" and "show tcp". */ |
| |
| static struct cmd_list_element *tcp_set_cmdlist; |
| static struct cmd_list_element *tcp_show_cmdlist; |
| |
| /* Whether to auto-retry refused connections. */ |
| |
| static bool tcp_auto_retry = true; |
| |
| /* Timeout period for connections, in seconds. */ |
| |
| static unsigned int tcp_retry_limit = 15; |
| |
| /* How many times per second to poll deprecated_ui_loop_hook. */ |
| |
| #define POLL_INTERVAL 5 |
| |
| /* Helper function to wait a while. If SOCK is not -1, wait on its |
| file descriptor. Otherwise just wait on a timeout, updating |
| *POLLS. Returns -1 on timeout or interrupt, otherwise the value of |
| select. */ |
| |
| static int |
| wait_for_connect (int sock, unsigned int *polls) |
| { |
| struct timeval t; |
| int n; |
| |
| /* While we wait for the connect to complete, |
| poll the UI so it can update or the user can |
| interrupt. */ |
| if (deprecated_ui_loop_hook && deprecated_ui_loop_hook (0)) |
| { |
| errno = EINTR; |
| return -1; |
| } |
| |
| /* Check for timeout. */ |
| if (*polls > tcp_retry_limit * POLL_INTERVAL) |
| { |
| errno = ETIMEDOUT; |
| return -1; |
| } |
| |
| /* Back off to polling once per second after the first POLL_INTERVAL |
| polls. */ |
| if (*polls < POLL_INTERVAL) |
| { |
| t.tv_sec = 0; |
| t.tv_usec = 1000000 / POLL_INTERVAL; |
| } |
| else |
| { |
| t.tv_sec = 1; |
| t.tv_usec = 0; |
| } |
| |
| if (sock >= 0) |
| { |
| fd_set rset, wset, eset; |
| |
| FD_ZERO (&rset); |
| FD_SET (sock, &rset); |
| wset = rset; |
| eset = rset; |
| |
| /* POSIX systems return connection success or failure by signalling |
| wset. Windows systems return success in wset and failure in |
| eset. |
| |
| We must call select here, rather than gdb_select, because |
| the serial structure has not yet been initialized - the |
| MinGW select wrapper will not know that this FD refers |
| to a socket. */ |
| n = select (sock + 1, &rset, &wset, &eset, &t); |
| } |
| else |
| /* Use gdb_select here, since we have no file descriptors, and on |
| Windows, plain select doesn't work in that case. */ |
| n = interruptible_select (0, NULL, NULL, NULL, &t); |
| |
| /* If we didn't time out, only count it as one poll. */ |
| if (n > 0 || *polls < POLL_INTERVAL) |
| (*polls)++; |
| else |
| (*polls) += POLL_INTERVAL; |
| |
| return n; |
| } |
| |
| /* Try to connect to the host represented by AINFO. If the connection |
| succeeds, return its socket. Otherwise, return -1 and set ERRNO |
| accordingly. POLLS is used when 'connect' returns EINPROGRESS, and |
| we need to invoke 'wait_for_connect' to obtain the status. */ |
| |
| static int |
| try_connect (const struct addrinfo *ainfo, unsigned int *polls) |
| { |
| int sock = gdb_socket_cloexec (ainfo->ai_family, ainfo->ai_socktype, |
| ainfo->ai_protocol); |
| |
| if (sock < 0) |
| return -1; |
| |
| /* Set socket nonblocking. */ |
| #ifdef USE_WIN32API |
| u_long ioarg = 1; |
| #else |
| int ioarg = 1; |
| #endif |
| |
| ioctl (sock, FIONBIO, &ioarg); |
| |
| /* Use Non-blocking connect. connect() will return 0 if connected |
| already. */ |
| if (connect (sock, ainfo->ai_addr, ainfo->ai_addrlen) < 0) |
| { |
| #ifdef USE_WIN32API |
| int err = WSAGetLastError(); |
| #else |
| int err = errno; |
| #endif |
| |
| /* If we've got a "connection refused" error, just return |
| -1. The caller will know what to do. */ |
| if ( |
| #ifdef USE_WIN32API |
| err == WSAECONNREFUSED |
| #else |
| err == ECONNREFUSED |
| #endif |
| ) |
| { |
| close (sock); |
| errno = err; |
| return -1; |
| } |
| |
| if ( |
| /* Any other error (except EINPROGRESS) will be "swallowed" |
| here. We return without specifying a return value, and |
| set errno if the caller wants to inspect what |
| happened. */ |
| #ifdef USE_WIN32API |
| /* Under Windows, calling "connect" with a non-blocking socket |
| results in WSAEWOULDBLOCK, not WSAEINPROGRESS. */ |
| err != WSAEWOULDBLOCK |
| #else |
| err != EINPROGRESS |
| #endif |
| ) |
| { |
| close (sock); |
| errno = err; |
| return -1; |
| } |
| |
| /* Looks like we need to wait for the connect. */ |
| int n; |
| |
| do |
| n = wait_for_connect (sock, polls); |
| while (n == 0); |
| |
| if (n < 0) |
| { |
| int saved_errno = errno; |
| |
| /* A negative value here means that we either timed out or |
| got interrupted by the user. Just return. */ |
| close (sock); |
| errno = saved_errno; |
| return -1; |
| } |
| } |
| |
| /* Got something. Is it an error? */ |
| int err; |
| socklen_t len = sizeof (err); |
| |
| /* On Windows, the fourth parameter to getsockopt is a "char *"; |
| on UNIX systems it is generally "void *". The cast to "char *" |
| is OK everywhere, since in C++ any data pointer type can be |
| implicitly converted to "void *". */ |
| int ret = getsockopt (sock, SOL_SOCKET, SO_ERROR, (char *) &err, &len); |
| |
| if (ret < 0) |
| { |
| int saved_errno = errno; |
| |
| close (sock); |
| errno = saved_errno; |
| return -1; |
| } |
| else if (ret == 0 && err != 0) |
| { |
| close (sock); |
| errno = err; |
| return -1; |
| } |
| |
| /* The connection succeeded. Return the socket. */ |
| return sock; |
| } |
| |
| /* Open a tcp socket. */ |
| |
| int |
| net_open (struct serial *scb, const char *name) |
| { |
| struct addrinfo hint; |
| struct addrinfo *ainfo; |
| |
| memset (&hint, 0, sizeof (hint)); |
| /* Assume no prefix will be passed, therefore we should use |
| AF_UNSPEC. */ |
| hint.ai_family = AF_UNSPEC; |
| hint.ai_socktype = SOCK_STREAM; |
| hint.ai_protocol = IPPROTO_TCP; |
| |
| parsed_connection_spec parsed = parse_connection_spec (name, &hint); |
| |
| if (parsed.port_str.empty ()) |
| error (_("Missing port on hostname '%s'"), name); |
| |
| int r = getaddrinfo (parsed.host_str.c_str (), |
| parsed.port_str.c_str (), |
| &hint, &ainfo); |
| |
| if (r != 0) |
| { |
| fprintf_unfiltered (gdb_stderr, _("%s: cannot resolve name: %s\n"), |
| name, gai_strerror (r)); |
| errno = ENOENT; |
| return -1; |
| } |
| |
| scoped_free_addrinfo free_ainfo (ainfo); |
| |
| /* Flag to indicate whether we've got a connection refused. It will |
| be true if any of the connections tried was refused. */ |
| bool got_connrefused; |
| /* If a connection succeeds, SUCCESS_AINFO will point to the |
| 'struct addrinfo' that succeed. */ |
| struct addrinfo *success_ainfo = NULL; |
| unsigned int polls = 0; |
| |
| /* Assume the worst. */ |
| scb->fd = -1; |
| |
| do |
| { |
| got_connrefused = false; |
| |
| for (addrinfo *iter = ainfo; iter != NULL; iter = iter->ai_next) |
| { |
| /* Iterate over the list of possible addresses to connect |
| to. For each, we'll try to connect and see if it |
| succeeds. */ |
| int sock = try_connect (iter, &polls); |
| |
| if (sock >= 0) |
| { |
| /* We've gotten a successful connection. Save its |
| 'struct addrinfo', the socket, and break. */ |
| success_ainfo = iter; |
| scb->fd = sock; |
| break; |
| } |
| else if ( |
| #ifdef USE_WIN32API |
| errno == WSAECONNREFUSED |
| #else |
| errno == ECONNREFUSED |
| #endif |
| ) |
| got_connrefused = true; |
| } |
| } |
| /* Just retry if: |
| |
| - tcp_auto_retry is true, and |
| - We haven't gotten a connection yet, and |
| - Any of our connection attempts returned with ECONNREFUSED, and |
| - wait_for_connect signals that we can keep going. */ |
| while (tcp_auto_retry |
| && success_ainfo == NULL |
| && got_connrefused |
| && wait_for_connect (-1, &polls) >= 0); |
| |
| if (success_ainfo == NULL) |
| { |
| net_close (scb); |
| return -1; |
| } |
| |
| /* Turn off nonblocking. */ |
| #ifdef USE_WIN32API |
| u_long ioarg = 0; |
| #else |
| int ioarg = 0; |
| #endif |
| |
| ioctl (scb->fd, FIONBIO, &ioarg); |
| |
| if (success_ainfo->ai_protocol == IPPROTO_TCP) |
| { |
| /* Disable Nagle algorithm. Needed in some cases. */ |
| int tmp = 1; |
| |
| setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY, |
| (char *) &tmp, sizeof (tmp)); |
| } |
| |
| #ifdef SIGPIPE |
| /* If we don't do this, then GDB simply exits |
| when the remote side dies. */ |
| signal (SIGPIPE, SIG_IGN); |
| #endif |
| |
| return 0; |
| } |
| |
| void |
| net_close (struct serial *scb) |
| { |
| if (scb->fd == -1) |
| return; |
| |
| close (scb->fd); |
| scb->fd = -1; |
| } |
| |
| int |
| net_read_prim (struct serial *scb, size_t count) |
| { |
| /* Need to cast to silence -Wpointer-sign on MinGW, as Winsock's |
| 'recv' takes 'char *' as second argument, while 'scb->buf' is |
| 'unsigned char *'. */ |
| return recv (scb->fd, (char *) scb->buf, count, 0); |
| } |
| |
| int |
| net_write_prim (struct serial *scb, const void *buf, size_t count) |
| { |
| /* On Windows, the second parameter to send is a "const char *"; on |
| UNIX systems it is generally "const void *". The cast to "const |
| char *" is OK everywhere, since in C++ any data pointer type can |
| be implicitly converted to "const void *". */ |
| return send (scb->fd, (const char *) buf, count, 0); |
| } |
| |
| int |
| ser_tcp_send_break (struct serial *scb) |
| { |
| /* Send telnet IAC and BREAK characters. */ |
| return (serial_write (scb, "\377\363", 2)); |
| } |
| |
| #ifndef USE_WIN32API |
| |
| /* The TCP ops. */ |
| |
| static const struct serial_ops tcp_ops = |
| { |
| "tcp", |
| net_open, |
| net_close, |
| NULL, |
| ser_base_readchar, |
| ser_base_write, |
| ser_base_flush_output, |
| ser_base_flush_input, |
| ser_tcp_send_break, |
| ser_base_raw, |
| ser_base_get_tty_state, |
| ser_base_copy_tty_state, |
| ser_base_set_tty_state, |
| ser_base_print_tty_state, |
| ser_base_setbaudrate, |
| ser_base_setstopbits, |
| ser_base_setparity, |
| ser_base_drain_output, |
| ser_base_async, |
| net_read_prim, |
| net_write_prim |
| }; |
| |
| #endif /* USE_WIN32API */ |
| |
| void _initialize_ser_tcp (); |
| void |
| _initialize_ser_tcp () |
| { |
| #ifdef USE_WIN32API |
| /* Do nothing; the TCP serial operations will be initialized in |
| ser-mingw.c. */ |
| #else |
| serial_add_interface (&tcp_ops); |
| #endif /* USE_WIN32API */ |
| |
| add_basic_prefix_cmd ("tcp", class_maintenance, _("\ |
| TCP protocol specific variables.\n\ |
| Configure variables specific to remote TCP connections."), |
| &tcp_set_cmdlist, |
| 0 /* allow-unknown */, &setlist); |
| add_show_prefix_cmd ("tcp", class_maintenance, _("\ |
| TCP protocol specific variables.\n\ |
| Configure variables specific to remote TCP connections."), |
| &tcp_show_cmdlist, |
| 0 /* allow-unknown */, &showlist); |
| |
| add_setshow_boolean_cmd ("auto-retry", class_obscure, |
| &tcp_auto_retry, _("\ |
| Set auto-retry on socket connect."), _("\ |
| Show auto-retry on socket connect."), |
| NULL, NULL, NULL, |
| &tcp_set_cmdlist, &tcp_show_cmdlist); |
| |
| add_setshow_uinteger_cmd ("connect-timeout", class_obscure, |
| &tcp_retry_limit, _("\ |
| Set timeout limit in seconds for socket connection."), _("\ |
| Show timeout limit in seconds for socket connection."), _("\ |
| If set to \"unlimited\", GDB will keep attempting to establish a\n\ |
| connection forever, unless interrupted with Ctrl-c.\n\ |
| The default is 15 seconds."), |
| NULL, NULL, |
| &tcp_set_cmdlist, &tcp_show_cmdlist); |
| } |