1 e9612918 2005-03-21 devnull /*
  2 e9612918 2005-03-21 devnull  * Multiplexor for sftp sessions.
  3 e9612918 2005-03-21 devnull  * Assumes can parse session with sftp> prompts.
  4 e9612918 2005-03-21 devnull  * Assumes clients are well-behaved and don't hang up the system.
  5 e9612918 2005-03-21 devnull  *
  6 e9612918 2005-03-21 devnull  * Stupid sftp bug: sftp invokes ssh, which always set O_NONBLOCK
  7 e9612918 2005-03-21 devnull  * on 0, 1, and 2.  Ssh inherits sftp's 2, so we can't use the output pipe
  8 fa325e9b 2020-01-10 cross  * on fd 2, since it will get set O_NONBLOCK, sftp won't notice, and
  9 e9612918 2005-03-21 devnull  * writes will be lost.  So instead we use a separate pipe for errors
 10 fa325e9b 2020-01-10 cross  * and consult it after each command.  Assume the pipe buffer is
 11 e9612918 2005-03-21 devnull  * big enough to hold the error output.
 12 e9612918 2005-03-21 devnull  */
 13 e9612918 2005-03-21 devnull #include <u.h>
 14 e9612918 2005-03-21 devnull #include <fcntl.h>
 15 e9612918 2005-03-21 devnull #include <libc.h>
 16 e9612918 2005-03-21 devnull #include <bio.h>
 17 e9612918 2005-03-21 devnull 
 18 e9612918 2005-03-21 devnull #undef pipe
 19 e9612918 2005-03-21 devnull 
 20 e9612918 2005-03-21 devnull int debug;
 21 e9612918 2005-03-21 devnull #define dprint if(debug)print
 22 e9612918 2005-03-21 devnull int sftpfd;
 23 e9612918 2005-03-21 devnull int sftperr;
 24 e9612918 2005-03-21 devnull Biobuf bin;
 25 e9612918 2005-03-21 devnull 
 26 e9612918 2005-03-21 devnull void
 27 e9612918 2005-03-21 devnull usage(void)
 28 e9612918 2005-03-21 devnull {
 29 e9612918 2005-03-21 devnull 	fprint(2, "usage: sftpcache system\n");
 30 e9612918 2005-03-21 devnull 	exits("usage");
 31 e9612918 2005-03-21 devnull }
 32 e9612918 2005-03-21 devnull 
 33 e9612918 2005-03-21 devnull char*
 34 e9612918 2005-03-21 devnull Brd(Biobuf *bin)
 35 e9612918 2005-03-21 devnull {
 36 e9612918 2005-03-21 devnull 	static char buf[1000];
 37 e9612918 2005-03-21 devnull 	int c, tot;
 38 fa325e9b 2020-01-10 cross 
 39 e9612918 2005-03-21 devnull 	tot = 0;
 40 e9612918 2005-03-21 devnull 	while((c = Bgetc(bin)) >= 0 && tot<sizeof buf){
 41 e9612918 2005-03-21 devnull 		buf[tot++] = c;
 42 e9612918 2005-03-21 devnull 		if(c == '\n'){
 43 e9612918 2005-03-21 devnull 			buf[tot] = 0;
 44 3ae1a866 2005-03-24 devnull 			dprint("OUT %s", buf);
 45 e9612918 2005-03-21 devnull 			return buf;
 46 e9612918 2005-03-21 devnull 		}
 47 e9612918 2005-03-21 devnull 		if(c == ' ' && tot == 6 && memcmp(buf, "sftp> ", 5) == 0){
 48 e9612918 2005-03-21 devnull 			buf[tot] = 0;
 49 3ae1a866 2005-03-24 devnull 			dprint("OUT %s\n", buf);
 50 e9612918 2005-03-21 devnull 			return buf;
 51 e9612918 2005-03-21 devnull 		}
 52 e9612918 2005-03-21 devnull 	}
 53 e9612918 2005-03-21 devnull 	if(tot == sizeof buf)
 54 e9612918 2005-03-21 devnull 		sysfatal("response too long");
 55 e9612918 2005-03-21 devnull 	return nil;
 56 e9612918 2005-03-21 devnull }
 57 e9612918 2005-03-21 devnull 
 58 e9612918 2005-03-21 devnull int
 59 e9612918 2005-03-21 devnull readstr(int fd, char *a, int n)
 60 e9612918 2005-03-21 devnull {
 61 e9612918 2005-03-21 devnull 	int i;
 62 fa325e9b 2020-01-10 cross 
 63 e9612918 2005-03-21 devnull 	for(i=0; i<n; i++){
 64 e9612918 2005-03-21 devnull 		if(read(fd, a+i, 1) != 1)
 65 e9612918 2005-03-21 devnull 			return -1;
 66 e9612918 2005-03-21 devnull 		if(a[i] == '\n'){
 67 e9612918 2005-03-21 devnull 			a[i] = 0;
 68 e9612918 2005-03-21 devnull 			return i;
 69 e9612918 2005-03-21 devnull 		}
 70 e9612918 2005-03-21 devnull 	}
 71 e9612918 2005-03-21 devnull 	return n;
 72 e9612918 2005-03-21 devnull }
 73 e9612918 2005-03-21 devnull 
 74 e9612918 2005-03-21 devnull void
 75 e9612918 2005-03-21 devnull doerrors(int fd)
 76 e9612918 2005-03-21 devnull {
 77 e9612918 2005-03-21 devnull 	char buf[100];
 78 3ae1a866 2005-03-24 devnull 	int n, first;
 79 fa325e9b 2020-01-10 cross 
 80 3ae1a866 2005-03-24 devnull 	first = 1;
 81 e9612918 2005-03-21 devnull 	while((n = read(sftperr, buf, sizeof buf)) > 0){
 82 3ae1a866 2005-03-24 devnull 		if(debug){
 83 3ae1a866 2005-03-24 devnull 			if(first){
 84 3ae1a866 2005-03-24 devnull 				first = 0;
 85 3ae1a866 2005-03-24 devnull 				fprint(2, "OUT errors:\n");
 86 3ae1a866 2005-03-24 devnull 			}
 87 e9612918 2005-03-21 devnull 			write(1, buf, n);
 88 3ae1a866 2005-03-24 devnull 		}
 89 e9612918 2005-03-21 devnull 		write(fd, buf, n);
 90 e9612918 2005-03-21 devnull 	}
 91 e9612918 2005-03-21 devnull }
 92 e9612918 2005-03-21 devnull 
 93 e9612918 2005-03-21 devnull void
 94 e9612918 2005-03-21 devnull bell(void *x, char *msg)
 95 e9612918 2005-03-21 devnull {
 96 e9612918 2005-03-21 devnull 	if(strcmp(msg, "sys: child") == 0 || strcmp(msg, "sys: write on closed pipe") == 0)
 97 e9612918 2005-03-21 devnull 		sysfatal("sftp exited");
 98 e9612918 2005-03-21 devnull 	if(strcmp(msg, "alarm") == 0)
 99 e9612918 2005-03-21 devnull 		noted(NCONT);
100 e9612918 2005-03-21 devnull 	noted(NDFLT);
101 e9612918 2005-03-21 devnull }
102 e9612918 2005-03-21 devnull 
103 e9612918 2005-03-21 devnull void
104 e9612918 2005-03-21 devnull main(int argc, char **argv)
105 e9612918 2005-03-21 devnull {
106 e9612918 2005-03-21 devnull 	char buf[200], cmd[1000], *q, *s;
107 e9612918 2005-03-21 devnull 	char dir[100], ndir[100];
108 e9612918 2005-03-21 devnull 	int p[2], px[2], pe[2], pid, ctl, nctl, fd, n;
109 fa325e9b 2020-01-10 cross 
110 e9612918 2005-03-21 devnull 	notify(bell);
111 e9612918 2005-03-21 devnull 	fmtinstall('H', encodefmt);
112 e9612918 2005-03-21 devnull 
113 e9612918 2005-03-21 devnull 	ARGBEGIN{
114 e9612918 2005-03-21 devnull 	case 'D':
115 e9612918 2005-03-21 devnull 		debug = 1;
116 e9612918 2005-03-21 devnull 		break;
117 e9612918 2005-03-21 devnull 	default:
118 e9612918 2005-03-21 devnull 		usage();
119 e9612918 2005-03-21 devnull 	}ARGEND
120 fa325e9b 2020-01-10 cross 
121 e9612918 2005-03-21 devnull 	if(argc != 1)
122 e9612918 2005-03-21 devnull 		usage();
123 fa325e9b 2020-01-10 cross 
124 e9612918 2005-03-21 devnull 	if(pipe(p) < 0 || pipe(px) < 0 || pipe(pe) < 0)
125 e9612918 2005-03-21 devnull 		sysfatal("pipe: %r");
126 e9612918 2005-03-21 devnull 	pid = fork();
127 e9612918 2005-03-21 devnull 	if(pid < 0)
128 e9612918 2005-03-21 devnull 		sysfatal("fork: %r");
129 e9612918 2005-03-21 devnull 	if(pid == 0){
130 e9612918 2005-03-21 devnull 		close(p[1]);
131 e9612918 2005-03-21 devnull 		close(px[0]);
132 e9612918 2005-03-21 devnull 		close(pe[0]);
133 e9612918 2005-03-21 devnull 		dup(p[0], 0);
134 e9612918 2005-03-21 devnull 		dup(px[1], 1);
135 e9612918 2005-03-21 devnull 		dup(pe[1], 2);
136 e9612918 2005-03-21 devnull 		if(p[0] > 2)
137 e9612918 2005-03-21 devnull 			close(p[0]);
138 e9612918 2005-03-21 devnull 		if(px[1] > 2)
139 e9612918 2005-03-21 devnull 			close(px[1]);
140 e9612918 2005-03-21 devnull 		if(pe[1] > 2)
141 e9612918 2005-03-21 devnull 			close(pe[1]);
142 e9612918 2005-03-21 devnull 		execl("sftp", "sftp", "-b", "/dev/stdin", argv[0], nil);
143 e9612918 2005-03-21 devnull 		sysfatal("exec sftp: %r");
144 e9612918 2005-03-21 devnull 	}
145 e9612918 2005-03-21 devnull 
146 e9612918 2005-03-21 devnull 	close(p[0]);
147 e9612918 2005-03-21 devnull 	close(px[1]);
148 e9612918 2005-03-21 devnull 	close(pe[1]);
149 e9612918 2005-03-21 devnull 
150 e9612918 2005-03-21 devnull 	sftpfd = p[1];
151 e9612918 2005-03-21 devnull 	sftperr = pe[0];
152 e9612918 2005-03-21 devnull 	Binit(&bin, px[0], OREAD);
153 e9612918 2005-03-21 devnull 
154 e9612918 2005-03-21 devnull 	fcntl(sftperr, F_SETFL, fcntl(sftperr, F_GETFL, 0)|O_NONBLOCK);
155 e9612918 2005-03-21 devnull 
156 e9612918 2005-03-21 devnull 	do
157 e9612918 2005-03-21 devnull 		q = Brd(&bin);
158 e9612918 2005-03-21 devnull 	while(q && strcmp(q, "sftp> ") != 0);
159 e9612918 2005-03-21 devnull 	if(q == nil)
160 e9612918 2005-03-21 devnull 		sysfatal("unexpected eof");
161 e9612918 2005-03-21 devnull 
162 e9612918 2005-03-21 devnull 	snprint(buf, sizeof buf, "unix!%s/%s.sftp", getns(), argv[0]);
163 e9612918 2005-03-21 devnull 	ctl = announce(buf, dir);
164 e9612918 2005-03-21 devnull 	if(ctl < 0)
165 e9612918 2005-03-21 devnull 		sysfatal("announce %s: %r", buf);
166 e9612918 2005-03-21 devnull 
167 e9612918 2005-03-21 devnull 	pid = fork();
168 e9612918 2005-03-21 devnull 	if(pid < 0)
169 e9612918 2005-03-21 devnull 		sysfatal("fork");
170 e9612918 2005-03-21 devnull 	if(pid != 0)
171 e9612918 2005-03-21 devnull 		exits(nil);
172 fa325e9b 2020-01-10 cross 
173 e9612918 2005-03-21 devnull 	for(;;){
174 e9612918 2005-03-21 devnull 		nctl = listen(dir, ndir);
175 e9612918 2005-03-21 devnull 		if(nctl < 0)
176 e9612918 2005-03-21 devnull 			sysfatal("listen %s: %r", buf);
177 e9612918 2005-03-21 devnull 		fd = accept(ctl, ndir);
178 e9612918 2005-03-21 devnull 		close(nctl);
179 e9612918 2005-03-21 devnull 		if(fd < 0)
180 e9612918 2005-03-21 devnull 			continue;
181 e9612918 2005-03-21 devnull 		for(;;){
182 cbeb0b26 2006-04-01 devnull 		/*	alarm(1000); */
183 e9612918 2005-03-21 devnull 			n = readstr(fd, cmd, sizeof cmd);
184 cbeb0b26 2006-04-01 devnull 		/*	alarm(0); */
185 e9612918 2005-03-21 devnull 			if(n <= 0)
186 e9612918 2005-03-21 devnull 				break;
187 e9612918 2005-03-21 devnull 			dprint("CMD %s\n", cmd);
188 3ae1a866 2005-03-24 devnull 			if(strcmp(cmd, "DONE") == 0){
189 3ae1a866 2005-03-24 devnull 				fprint(fd, "DONE\n");
190 e9612918 2005-03-21 devnull 				break;
191 3ae1a866 2005-03-24 devnull 			}
192 3ae1a866 2005-03-24 devnull 			fprint(sftpfd, "-%s\n", cmd);
193 e9612918 2005-03-21 devnull 			q = Brd(&bin);
194 e9612918 2005-03-21 devnull 			if(*q==0 || q[strlen(q)-1] != '\n')
195 e9612918 2005-03-21 devnull 				sysfatal("unexpected response");
196 e9612918 2005-03-21 devnull 			q[strlen(q)-1] = 0;
197 3ae1a866 2005-03-24 devnull 			if(q[0] != '-' || strcmp(q+1, cmd) != 0)
198 e9612918 2005-03-21 devnull 				sysfatal("unexpected response");
199 e9612918 2005-03-21 devnull 			while((q = Brd(&bin)) != nil){
200 e9612918 2005-03-21 devnull 				if(strcmp(q, "sftp> ") == 0){
201 e9612918 2005-03-21 devnull 					doerrors(fd);
202 e9612918 2005-03-21 devnull 					break;
203 e9612918 2005-03-21 devnull 				}
204 e9612918 2005-03-21 devnull 				s = q+strlen(q);
205 e9612918 2005-03-21 devnull 				while(s > q && (s[-1] == ' ' || s[-1] == '\n' || s[-1] == '\t' || s[-1] == '\r'))
206 e9612918 2005-03-21 devnull 					s--;
207 e9612918 2005-03-21 devnull 				*s = 0;
208 e9612918 2005-03-21 devnull 				fprint(fd, "%s\n", q);
209 e9612918 2005-03-21 devnull 			}
210 e9612918 2005-03-21 devnull 			if(q == nil){
211 e9612918 2005-03-21 devnull 				fprint(fd, "!!! unexpected eof\n");
212 e9612918 2005-03-21 devnull 				sysfatal("unexpected eof");
213 e9612918 2005-03-21 devnull 			}
214 e9612918 2005-03-21 devnull 		}
215 e9612918 2005-03-21 devnull 		close(fd);
216 e9612918 2005-03-21 devnull 	}
217 e9612918 2005-03-21 devnull }