Better pid handling.

[rsync/rsync.git] / main.c

/* -*- c-file-style: "linux" -*-

   Copyright (C) 1996-2001 by Andrew Tridgell <tridge@samba.org>
   Copyright (C) Paul Mackerras 1996
   Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>

   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 2 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rsync.h"

time_t starttime = 0;

extern struct stats stats;
extern int am_root;
extern int am_server;
extern int am_sender;
extern int am_daemon;
extern int verbose;
extern int blocking_io;
extern int cvs_exclude;
extern int delete_mode;
extern int delete_excluded;
extern int delete_after;
extern int daemon_over_rsh;
extern int do_stats;
extern int dry_run;
extern int list_only;
extern int local_server;
extern int log_got_error;
extern int module_id;
extern int orig_umask;
extern int preserve_hard_links;
extern int protocol_version;
extern int recurse;
extern int relative_paths;
extern int rsync_port;
extern int read_batch;
extern int write_batch;
extern int filesfrom_fd;
extern pid_t cleanup_child_pid;
extern char *files_from;
extern char *remote_filesfrom_file;
extern char *rsync_path;
extern char *shell_cmd;
extern struct file_list *batch_flist;

/* there's probably never more than at most 2 outstanding child processes,
 * but set it higher just in case.
 */
#define MAXCHILDPROCS 5

struct pid_status {
	pid_t pid;
	int   status;
} pid_stat_table[MAXCHILDPROCS];

static void show_malloc_stats(void);

/****************************************************************************
wait for a process to exit, calling io_flush while waiting
****************************************************************************/
void wait_process(pid_t pid, int *status)
{
	pid_t waited_pid;
	int cnt;

	while ((waited_pid = waitpid(pid, status, WNOHANG)) == 0) {
		msleep(20);
		io_flush(FULL_FLUSH);
	}

	if ((waited_pid == -1) && (errno == ECHILD)) {
		/* status of requested child no longer available.
		 * check to see if it was processed by the sigchld_handler.
		 */
		for (cnt = 0;  cnt < MAXCHILDPROCS; cnt++) {
			if (pid == pid_stat_table[cnt].pid) {
				*status = pid_stat_table[cnt].status;
				pid_stat_table[cnt].pid = 0;
				break;
			}
		}
	}

	/* TODO: If the child exited on a signal, then log an
	 * appropriate error message.  Perhaps we should also accept a
	 * message describing the purpose of the child.  Also indicate
	 * this to the caller so that thhey know something went
	 * wrong.  */
	*status = WEXITSTATUS(*status);
}

static void report(int f)
{
	time_t t = time(NULL);
	int send_stats;

	if (do_stats && verbose > 1) {
		/* These come out from every process */
		show_malloc_stats();
		show_flist_stats();
	}

	if (am_daemon) {
		log_exit(0, __FILE__, __LINE__);
		if (f == -1 || !am_sender) return;
	}

	send_stats = verbose || protocol_version >= 20;
	if (am_server) {
		if (am_sender && send_stats) {
			int64 w;
			/* store total_written in a temporary
			 * because write_longint changes it */
			w = stats.total_written;
			write_longint(f,stats.total_read);
			write_longint(f,w);
			write_longint(f,stats.total_size);
		}
		return;
	}

	/* this is the client */

	if (!am_sender && send_stats) {
		int64 r;
		stats.total_written = read_longint(f);
		/* store total_read in a temporary, read_longint changes it */
		r = read_longint(f);
		stats.total_size = read_longint(f);
		stats.total_read = r;
	}

	if (do_stats) {
		if (!am_sender && !send_stats) {
			/* missing the bytes written by the generator */
			rprintf(FINFO, "\nCannot show stats as receiver because remote protocol version is less than 20\n");
			rprintf(FINFO, "Use --stats -v to show stats\n");
			return;
		}
		rprintf(FINFO,"\nNumber of files: %d\n", stats.num_files);
		rprintf(FINFO,"Number of files transferred: %d\n",
			stats.num_transferred_files);
		rprintf(FINFO,"Total file size: %.0f bytes\n",
			(double)stats.total_size);
		rprintf(FINFO,"Total transferred file size: %.0f bytes\n",
			(double)stats.total_transferred_size);
		rprintf(FINFO,"Literal data: %.0f bytes\n",
			(double)stats.literal_data);
		rprintf(FINFO,"Matched data: %.0f bytes\n",
			(double)stats.matched_data);
		rprintf(FINFO,"File list size: %d\n", stats.flist_size);
		rprintf(FINFO,"Total bytes written: %.0f\n",
			(double)stats.total_written);
		rprintf(FINFO,"Total bytes read: %.0f\n",
			(double)stats.total_read);
	}

	if (verbose || do_stats) {
		rprintf(FINFO,"\nwrote %.0f bytes  read %.0f bytes  %.2f bytes/sec\n",
			(double)stats.total_written,
			(double)stats.total_read,
			(stats.total_written+stats.total_read)/(0.5 + (t-starttime)));
		rprintf(FINFO,"total size is %.0f  speedup is %.2f\n",
			(double)stats.total_size,
			(1.0*stats.total_size)/(stats.total_written+stats.total_read));
	}

	fflush(stdout);
	fflush(stderr);
}


/**
 * If our C library can get malloc statistics, then show them to FINFO
 **/
static void show_malloc_stats(void)
{
#ifdef HAVE_MALLINFO
	struct mallinfo mi;

	mi = mallinfo();

	rprintf(FINFO, "\n" RSYNC_NAME "[%d] (%s%s%s) heap statistics:\n",
		getpid(),
		am_server ? "server " : "",
		am_daemon ? "daemon " : "",
		am_sender ? "sender" : "receiver");
	rprintf(FINFO, "  arena:     %10d   (bytes from sbrk)\n", mi.arena);
	rprintf(FINFO, "  ordblks:   %10d   (chunks not in use)\n", mi.ordblks);
	rprintf(FINFO, "  smblks:    %10d\n", mi.smblks);
	rprintf(FINFO, "  hblks:     %10d   (chunks from mmap)\n", mi.hblks);
	rprintf(FINFO, "  hblkhd:    %10d   (bytes from mmap)\n", mi.hblkhd);
	rprintf(FINFO, "  usmblks:   %10d\n", mi.usmblks);
	rprintf(FINFO, "  fsmblks:   %10d\n", mi.fsmblks);
	rprintf(FINFO, "  uordblks:  %10d   (bytes used)\n", mi.uordblks);
	rprintf(FINFO, "  fordblks:  %10d   (bytes free)\n", mi.fordblks);
	rprintf(FINFO, "  keepcost:  %10d   (bytes in releasable chunk)\n", mi.keepcost);
#endif /* HAVE_MALLINFO */
}


/* Start the remote shell.   cmd may be NULL to use the default. */
static pid_t do_cmd(char *cmd,char *machine,char *user,char *path,int *f_in,int *f_out)
{
	char *args[100];
	int i,argc=0;
	pid_t ret;
	char *tok,*dir=NULL;
	int dash_l_set = 0;

	if (!read_batch && !local_server) {
		char *rsh_env = getenv(RSYNC_RSH_ENV);
		if (!cmd)
			cmd = rsh_env;
		if (!cmd)
			cmd = RSYNC_RSH;
		cmd = strdup(cmd);
		if (!cmd)
			goto oom;

		for (tok=strtok(cmd," ");tok;tok=strtok(NULL," ")) {
			args[argc++] = tok;
		}

		/* check to see if we've already been given '-l user' in
		 * the remote-shell command */
		for (i = 0; i < argc-1; i++) {
			if (!strcmp(args[i], "-l") && args[i+1][0] != '-')
				dash_l_set = 1;
		}

#if HAVE_REMSH
		/* remsh (on HPUX) takes the arguments the other way around */
		args[argc++] = machine;
		if (user && !(daemon_over_rsh && dash_l_set)) {
			args[argc++] = "-l";
			args[argc++] = user;
		}
#else
		if (user && !(daemon_over_rsh && dash_l_set)) {
			args[argc++] = "-l";
			args[argc++] = user;
		}
		args[argc++] = machine;
#endif

		args[argc++] = rsync_path;

		if (blocking_io < 0) {
			char *cp;
			if ((cp = strrchr(cmd, '/')) != NULL)
				cp++;
			else
				cp = cmd;
			if (strcmp(cp, "rsh") == 0 || strcmp(cp, "remsh") == 0)
				blocking_io = 1;
		}

		server_options(args,&argc);
	}

	args[argc++] = ".";

	if (!daemon_over_rsh && path && *path)
		args[argc++] = path;

	args[argc] = NULL;

	if (verbose > 3) {
		rprintf(FINFO,"cmd=");
		for (i=0;i<argc;i++)
			rprintf(FINFO,"%s ",args[i]);
		rprintf(FINFO,"\n");
	}

	if (local_server) {
		if (read_batch)
			create_flist_from_batch(); /* sets batch_flist */
		ret = local_child(argc, args, f_in, f_out, child_main);
	} else {
		ret = piped_child(args,f_in,f_out);
	}

	if (dir) free(dir);

	return ret;

oom:
	out_of_memory("do_cmd");
	return 0; /* not reached */
}




static char *get_local_name(struct file_list *flist,char *name)
{
	STRUCT_STAT st;
	int e;

	if (verbose > 2)
		rprintf(FINFO,"get_local_name count=%d %s\n",
			flist->count, NS(name));

	if (!name)
		return NULL;

	if (do_stat(name,&st) == 0) {
		if (S_ISDIR(st.st_mode)) {
			if (!push_dir(name)) {
				rprintf(FERROR, "push_dir %s failed: %s (1)\n",
					full_fname(name), strerror(errno));
				exit_cleanup(RERR_FILESELECT);
			}
			return NULL;
		}
		if (flist->count > 1) {
			rprintf(FERROR,"ERROR: destination must be a directory when copying more than 1 file\n");
			exit_cleanup(RERR_FILESELECT);
		}
		return name;
	}

	if (flist->count <= 1 && ((e = strlen(name)) <= 1 || name[e-1] != '/'))
		return name;

	if (do_mkdir(name,0777 & ~orig_umask) != 0) {
		rprintf(FERROR, "mkdir %s failed: %s\n",
			full_fname(name), strerror(errno));
		exit_cleanup(RERR_FILEIO);
	} else {
		if (verbose > 0)
			rprintf(FINFO,"created directory %s\n",name);
	}

	if (!push_dir(name)) {
		rprintf(FERROR, "push_dir %s failed: %s (2)\n",
			full_fname(name), strerror(errno));
		exit_cleanup(RERR_FILESELECT);
	}

	return NULL;
}


static void do_server_sender(int f_in, int f_out, int argc,char *argv[])
{
	int i;
	struct file_list *flist;
	char *dir = argv[0];

	if (verbose > 2)
		rprintf(FINFO,"server_sender starting pid=%d\n",(int)getpid());

	if (!relative_paths && !push_dir(dir)) {
		rprintf(FERROR, "push_dir %s failed: %s (3)\n",
			full_fname(dir), strerror(errno));
		exit_cleanup(RERR_FILESELECT);
	}
	argc--;
	argv++;

	if (strcmp(dir,".")) {
		int l = strlen(dir);
		if (strcmp(dir,"/") == 0)
			l = 0;
		for (i=0;i<argc;i++)
			argv[i] += l+1;
	}

	if (argc == 0 && recurse) {
		argc=1;
		argv--;
		argv[0] = ".";
	}

	flist = send_file_list(f_out,argc,argv);
	if (!flist || flist->count == 0) {
		exit_cleanup(0);
	}

	io_start_buffering_in(f_in);
	io_start_buffering_out(f_out);
	send_files(flist,f_out,f_in);
	io_flush(FULL_FLUSH);
	report(f_out);
	if (protocol_version >= 24) {
		/* final goodbye message */
		read_int(f_in);
	}
	io_flush(FULL_FLUSH);
	exit_cleanup(0);
}


static int do_recv(int f_in,int f_out,struct file_list *flist,char *local_name)
{
	int pid;
	int status=0;
	int error_pipe[2];

	if (preserve_hard_links)
		init_hard_links(flist);

	if (!delete_after) {
		/* I moved this here from recv_files() to prevent a race condition */
		if (recurse && delete_mode && !local_name && flist->count>0) {
			delete_files(flist);
		}
	}

	if (fd_pair(error_pipe) < 0) {
		rprintf(FERROR,"error pipe failed in do_recv\n");
		exit_cleanup(RERR_SOCKETIO);
	}

	io_flush(NORMAL_FLUSH);

	if ((pid=do_fork()) == 0) {
		close(error_pipe[0]);
		if (f_in != f_out) close(f_out);

		/* we can't let two processes write to the socket at one time */
		io_multiplexing_close();

		/* set place to send errors */
		set_msg_fd_out(error_pipe[1]);

		recv_files(f_in,flist,local_name);
		io_flush(FULL_FLUSH);
		report(f_in);

		send_msg(MSG_DONE, "", 0);
		io_flush(FULL_FLUSH);
		/* finally we go to sleep until our parent kills us
		 * with a USR2 signal. We sleep for a short time as on
		 * some OSes a signal won't interrupt a sleep! */
		while (1)
			msleep(20);
	}

	close(error_pipe[1]);
	if (f_in != f_out) close(f_in);

	io_start_buffering_out(f_out);

	set_msg_fd_in(error_pipe[0]);

	generate_files(f_out, flist, local_name);

	get_redo_num(); /* Read final MSG_DONE and any prior messages. */
	io_flush(FULL_FLUSH);
	if (protocol_version >= 24) {
		/* send a final goodbye message */
		write_int(f_out, -1);
	}
	io_flush(FULL_FLUSH);

	set_msg_fd_in(-1);
	kill(pid, SIGUSR2);
	wait_process(pid, &status);
	return status;
}


static void do_server_recv(int f_in, int f_out, int argc,char *argv[])
{
	int status;
	struct file_list *flist;
	char *local_name=NULL;
	char *dir = NULL;

	if (verbose > 2)
		rprintf(FINFO,"server_recv(%d) starting pid=%d\n",argc,(int)getpid());

	if (am_daemon && lp_read_only(module_id) && !am_sender) {
		rprintf(FERROR,"ERROR: module is read only\n");
		exit_cleanup(RERR_SYNTAX);
		return;
	}


	if (argc > 0) {
		dir = argv[0];
		argc--;
		argv++;
		if (!am_daemon && !push_dir(dir)) {
			rprintf(FERROR, "push_dir %s failed: %s (4)\n",
				full_fname(dir), strerror(errno));
			exit_cleanup(RERR_FILESELECT);
		}
	}

	io_start_buffering_in(f_in);
	if (delete_mode && !delete_excluded)
		recv_exclude_list(f_in);

	if (filesfrom_fd >= 0) {
		/* We're receiving the file info from the sender, so we need
		 * the IO routines to automatically write out the names onto
		 * our f_out socket as we read the list info from the sender.
		 * This avoids both deadlock and extra delays/buffers. */
		io_set_filesfrom_fds(filesfrom_fd, f_out);
		filesfrom_fd = -1;
	}

	if (read_batch)
		flist = batch_flist;
	else
		flist = recv_file_list(f_in);
	if (!flist) {
		rprintf(FERROR,"server_recv: recv_file_list error\n");
		exit_cleanup(RERR_FILESELECT);
	}

	if (argc > 0) {
		if (strcmp(dir,".")) {
			argv[0] += strlen(dir);
			if (argv[0][0] == '/') argv[0]++;
		}
		local_name = get_local_name(flist,argv[0]);
	}

	status = do_recv(f_in,f_out,flist,local_name);
	exit_cleanup(status);
}


int child_main(int argc, char *argv[])
{
	start_server(STDIN_FILENO, STDOUT_FILENO, argc, argv);
	return 0;
}


void start_server(int f_in, int f_out, int argc, char *argv[])
{
	setup_protocol(f_out, f_in);

	set_nonblocking(f_in);
	set_nonblocking(f_out);

	if (protocol_version >= 23)
		io_start_multiplex_out(f_out);

	if (am_sender) {
		if (!read_batch) {
			recv_exclude_list(f_in);
			if (cvs_exclude)
				add_cvs_excludes();
		}
		do_server_sender(f_in, f_out, argc, argv);
	} else {
		do_server_recv(f_in, f_out, argc, argv);
	}
	exit_cleanup(0);
}


/*
 * This is called once the connection has been negotiated.  It is used
 * for rsyncd, remote-shell, and local connections.
 */
int client_run(int f_in, int f_out, pid_t pid, int argc, char *argv[])
{
	struct file_list *flist = NULL;
	int status = 0, status2 = 0;
	char *local_name = NULL;

	cleanup_child_pid = pid;
	if (read_batch)
		flist = batch_flist;

	set_nonblocking(f_in);
	set_nonblocking(f_out);

	setup_protocol(f_out,f_in);

	if (protocol_version >= 23)
		io_start_multiplex_in(f_in);

	if (am_sender) {
		io_start_buffering_out(f_out);
		if (cvs_exclude)
			add_cvs_excludes();
		if (delete_mode && !delete_excluded)
			send_exclude_list(f_out);
		if (remote_filesfrom_file)
			filesfrom_fd = f_in;
		if (!read_batch) /* don't write to pipe */
			flist = send_file_list(f_out,argc,argv);
		if (verbose > 3)
			rprintf(FINFO,"file list sent\n");

		io_flush(NORMAL_FLUSH);
		send_files(flist,f_out,f_in);
		io_flush(FULL_FLUSH);
		if (protocol_version >= 24) {
			/* final goodbye message */
			read_int(f_in);
		}
		if (pid != -1) {
			if (verbose > 3)
				rprintf(FINFO,"client_run waiting on %d\n", (int) pid);
			io_flush(FULL_FLUSH);
			wait_process(pid, &status);
		}
		report(-1);
		io_flush(FULL_FLUSH);
		exit_cleanup(status);
	}

	if (argc == 0) {
		list_only = 1;
	}

	if (!write_batch)
		send_exclude_list(f_out);

	if (filesfrom_fd >= 0) {
		io_set_filesfrom_fds(filesfrom_fd, f_out);
		filesfrom_fd = -1;
	}

	flist = recv_file_list(f_in);
	if (!flist || flist->count == 0) {
		rprintf(FINFO, "client: nothing to do: "
			"perhaps you need to specify some filenames or "
			"the --recursive option?\n");
		exit_cleanup(0);
	}

	local_name = get_local_name(flist,argv[0]);

	status2 = do_recv(f_in,f_out,flist,local_name);

	if (pid != -1) {
		if (verbose > 3)
			rprintf(FINFO,"client_run2 waiting on %d\n", (int) pid);
		io_flush(FULL_FLUSH);
		wait_process(pid, &status);
	}

	return MAX(status, status2);
}

static int copy_argv (char *argv[])
{
	int i;

	for (i = 0; argv[i]; i++) {
		if (!(argv[i] = strdup(argv[i]))) {
			rprintf (FERROR, "out of memory at %s(%d)\n",
				 __FILE__, __LINE__);
			return RERR_MALLOC;
		}
	}

	return 0;
}


/**
 * Start a client for either type of remote connection.  Work out
 * whether the arguments request a remote shell or rsyncd connection,
 * and call the appropriate connection function, then run_client.
 *
 * Calls either start_socket_client (for sockets) or do_cmd and
 * client_run (for ssh).
 **/
static int start_client(int argc, char *argv[])
{
	char *p;
	char *shell_machine = NULL;
	char *shell_path = NULL;
	char *shell_user = NULL;
	int ret;
	pid_t pid;
	int f_in,f_out;
	int rc;

	/* Don't clobber argv[] so that ps(1) can still show the right
	 * command line. */
	if ((rc = copy_argv(argv)))
		return rc;

	/* rsync:// always uses rsync server over direct socket connection */
	if (strncasecmp(URL_PREFIX, argv[0], strlen(URL_PREFIX)) == 0) {
		char *host, *path;

		host = argv[0] + strlen(URL_PREFIX);
		p = strchr(host,'/');
		if (p) {
			*p = 0;
			path = p+1;
		} else {
			path = "";
		}
		p = strchr(host,':');
		if (p) {
			rsync_port = atoi(p+1);
			*p = 0;
		}
		return start_socket_client(host, path, argc-1, argv+1);
	}

	if (!read_batch) {
		p = find_colon(argv[0]);
		if (p) {
			if (remote_filesfrom_file
			 && remote_filesfrom_file != files_from + 1
			 && strncmp(files_from, argv[0], p-argv[0]+1) != 0) {
				rprintf(FERROR,
					"--files-from hostname is not transfer hostname\n");
				exit_cleanup(RERR_SYNTAX);
			}
			if (p[1] == ':') { /* double colon */
				*p = 0;
				if (!shell_cmd) {
					return start_socket_client(argv[0], p+2,
								   argc-1, argv+1);
				}
				p++;
				daemon_over_rsh = 1;
			}

			if (argc < 1) {
				usage(FERROR);
				exit_cleanup(RERR_SYNTAX);
			}

			am_sender = 0;
			*p = 0;
			shell_machine = argv[0];
			shell_path = p+1;
			argc--;
			argv++;
		} else {
			am_sender = 1;

			/* rsync:// destination uses rsync server over direct socket */
			if (strncasecmp(URL_PREFIX, argv[argc-1], strlen(URL_PREFIX)) == 0) {
				char *host, *path;

				host = argv[argc-1] + strlen(URL_PREFIX);
				p = strchr(host,'/');
				if (p) {
					*p = 0;
					path = p+1;
				} else {
					path = "";
				}
				p = strchr(host,':');
				if (p) {
					rsync_port = atoi(p+1);
					*p = 0;
				}
				return start_socket_client(host, path, argc-1, argv);
			}

			p = find_colon(argv[argc-1]);
			if (p && remote_filesfrom_file
			 && remote_filesfrom_file != files_from + 1
			 && strncmp(files_from, argv[argc-1], p-argv[argc-1]+1) != 0) {
				rprintf(FERROR,
					"--files-from hostname is not transfer hostname\n");
				exit_cleanup(RERR_SYNTAX);
			}
			if (!p) {
				local_server = 1;
				if (remote_filesfrom_file) {
					rprintf(FERROR,
						"--files-from is remote but transfer is local\n");
					exit_cleanup(RERR_SYNTAX);
				}
			} else if (p[1] == ':') { /* double colon */
				*p = 0;
				if (!shell_cmd) {
					return start_socket_client(argv[argc-1], p+2,
								   argc-1, argv);
				}
				p++;
				daemon_over_rsh = 1;
			}

			if (argc < 2) {
				usage(FERROR);
				exit_cleanup(RERR_SYNTAX);
			}

			if (local_server) {
				shell_machine = NULL;
				shell_path = argv[argc-1];
			} else {
				*p = 0;
				shell_machine = argv[argc-1];
				shell_path = p+1;
			}
			argc--;
		}
	} else {
		am_sender = 1;
		local_server = 1;
		shell_path = argv[argc-1];
	}

	if (shell_machine) {
		p = strrchr(shell_machine,'@');
		if (p) {
			*p = 0;
			shell_user = shell_machine;
			shell_machine = p+1;
		}
	}

	if (verbose > 3) {
		rprintf(FINFO,"cmd=%s machine=%s user=%s path=%s\n",
			shell_cmd?shell_cmd:"",
			shell_machine?shell_machine:"",
			shell_user?shell_user:"",
			shell_path?shell_path:"");
	}

	if (!am_sender && argc > 1) {
		usage(FERROR);
		exit_cleanup(RERR_SYNTAX);
	}

	if (argc == 0 && !am_sender) {
		list_only = 1;
	}

	pid = do_cmd(shell_cmd,shell_machine,shell_user,shell_path,
		     &f_in,&f_out);

	/* if we're running an rsync server on the remote host over a
	 * remote shell command, we need to do the RSYNCD protocol first */
	if (daemon_over_rsh) {
		int tmpret;
		tmpret = start_inband_exchange(shell_user, shell_path,
					       f_in, f_out, argc);
		if (tmpret < 0)
			return tmpret;
	}

	ret = client_run(f_in, f_out, pid, argc, argv);

	fflush(stdout);
	fflush(stderr);

	return ret;
}


static RETSIGTYPE sigusr1_handler(UNUSED(int val))
{
	exit_cleanup(RERR_SIGNAL);
}

static RETSIGTYPE sigusr2_handler(UNUSED(int val))
{
	if (log_got_error) _exit(RERR_PARTIAL);
	_exit(0);
}

static RETSIGTYPE sigchld_handler(UNUSED(int val))
{
#ifdef WNOHANG
	int cnt, status;
	pid_t pid;
	/* An empty waitpid() loop was put here by Tridge and we could never
	 * get him to explain why he put it in, so rather than taking it
	 * out we're instead saving the child exit statuses for later use.
	 * The waitpid() loop presumably eliminates all possibility of leaving
	 * zombie children, maybe that's why he did it.
	 */
	while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
		/* save the child's exit status */
		for (cnt = 0; cnt < MAXCHILDPROCS; cnt++) {
			if (pid_stat_table[cnt].pid == 0) {
				pid_stat_table[cnt].pid = pid;
				pid_stat_table[cnt].status = status;
				break;
			}
		}
	}
#endif
}


/**
 * This routine catches signals and tries to send them to gdb.
 *
 * Because it's called from inside a signal handler it ought not to
 * use too many library routines.
 *
 * @todo Perhaps use "screen -X" instead/as well, to help people
 * debugging without easy access to X.  Perhaps use an environment
 * variable, or just call a script?
 *
 * @todo The /proc/ magic probably only works on Linux (and
 * Solaris?)  Can we be more portable?
 **/
#ifdef MAINTAINER_MODE
const char *get_panic_action(void)
{
	const char *cmd_fmt = getenv("RSYNC_PANIC_ACTION");

	if (cmd_fmt)
		return cmd_fmt;
	else
		return "xterm -display :0 -T Panic -n Panic "
			"-e gdb /proc/%d/exe %d";
}


/**
 * Handle a fatal signal by launching a debugger, controlled by $RSYNC_PANIC_ACTION.
 *
 * This signal handler is only installed if we were configured with
 * --enable-maintainer-mode.  Perhaps it should always be on and we
 * should just look at the environment variable, but I'm a bit leery
 * of a signal sending us into a busy loop.
 **/
static RETSIGTYPE rsync_panic_handler(UNUSED(int whatsig))
{
	char cmd_buf[300];
	int ret;

	sprintf(cmd_buf, get_panic_action(),
		getpid(), getpid());

	/* Unless we failed to execute gdb, we allow the process to
	 * continue.  I'm not sure if that's right. */
	ret = system(cmd_buf);
	if (ret)
		_exit(ret);
}
#endif


int main(int argc,char *argv[])
{
	int ret;
	int orig_argc;
	char **orig_argv;

	orig_argc = argc;
	orig_argv = argv;

	signal(SIGUSR1, sigusr1_handler);
	signal(SIGUSR2, sigusr2_handler);
	signal(SIGCHLD, sigchld_handler);
#ifdef MAINTAINER_MODE
	signal(SIGSEGV, rsync_panic_handler);
	signal(SIGFPE, rsync_panic_handler);
	signal(SIGABRT, rsync_panic_handler);
	signal(SIGBUS, rsync_panic_handler);
#endif /* def MAINTAINER_MODE */

	starttime = time(NULL);
	am_root = (getuid() == 0);

	memset(&stats, 0, sizeof(stats));

	if (argc < 2) {
		usage(FERROR);
		exit_cleanup(RERR_SYNTAX);
	}

	/* we set a 0 umask so that correct file permissions can be
	 * carried across */
	orig_umask = (int)umask(0);

	if (!parse_arguments(&argc, (const char ***) &argv, 1)) {
		/* FIXME: We ought to call the same error-handling
		 * code here, rather than relying on getopt. */
		option_error();
		exit_cleanup(RERR_SYNTAX);
	}

	signal(SIGINT,SIGNAL_CAST sig_int);
	signal(SIGHUP,SIGNAL_CAST sig_int);
	signal(SIGTERM,SIGNAL_CAST sig_int);

	/* Ignore SIGPIPE; we consistently check error codes and will
	 * see the EPIPE. */
	signal(SIGPIPE, SIG_IGN);

	/* Initialize push_dir here because on some old systems getcwd
	 * (implemented by forking "pwd" and reading its output) doesn't
	 * work when there are other child processes.  Also, on all systems
	 * that implement getcwd that way "pwd" can't be found after chroot. */
	push_dir(NULL);

	if (write_batch && !am_server) {
		write_batch_argvs_file(orig_argc, orig_argv);
	}

	if (am_daemon && !am_server)
		return daemon_main();

	if (argc < 1) {
		usage(FERROR);
		exit_cleanup(RERR_SYNTAX);
	}

	if (dry_run)
		verbose = MAX(verbose,1);

#ifndef SUPPORT_LINKS
	if (!am_server && preserve_links) {
		rprintf(FERROR,"ERROR: symbolic links not supported\n");
		exit_cleanup(RERR_UNSUPPORTED);
	}
#endif

	if (am_server) {
		set_nonblocking(STDIN_FILENO);
		set_nonblocking(STDOUT_FILENO);
		if (am_daemon)
			return start_daemon(STDIN_FILENO, STDOUT_FILENO);
		start_server(STDIN_FILENO, STDOUT_FILENO, argc, argv);
	}

	ret = start_client(argc, argv);
	if (ret == -1)
		exit_cleanup(RERR_STARTCLIENT);
	else
		exit_cleanup(ret);

	return ret;
}