2 * sftp.c: SFTP generic client code.
13 #define smalloc malloc
14 #define srealloc realloc
17 #define GET_32BIT(cp) \
18 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
19 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
20 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
21 ((unsigned long)(unsigned char)(cp)[3]))
23 #define PUT_32BIT(cp, value) { \
24 (cp)[0] = (unsigned char)((value) >> 24); \
25 (cp)[1] = (unsigned char)((value) >> 16); \
26 (cp)[2] = (unsigned char)((value) >> 8); \
27 (cp)[3] = (unsigned char)(value); }
36 /* ----------------------------------------------------------------------
37 * SFTP packet construction functions.
39 static void sftp_pkt_ensure(struct sftp_packet *pkt, int length) {
40 if (pkt->maxlen < length) {
41 pkt->maxlen = length + 256;
42 pkt->data = srealloc(pkt->data, pkt->maxlen);
45 static void sftp_pkt_adddata(struct sftp_packet *pkt, void *data, int len) {
47 sftp_pkt_ensure(pkt, pkt->length);
48 memcpy(pkt->data+pkt->length-len, data, len);
50 static void sftp_pkt_addbyte(struct sftp_packet *pkt, unsigned char byte) {
51 sftp_pkt_adddata(pkt, &byte, 1);
53 static struct sftp_packet *sftp_pkt_init(int pkt_type) {
54 struct sftp_packet *pkt;
55 pkt = smalloc(sizeof(struct sftp_packet));
60 sftp_pkt_addbyte(pkt, (unsigned char)pkt_type);
63 static void sftp_pkt_addbool(struct sftp_packet *pkt, unsigned char value) {
64 sftp_pkt_adddata(pkt, &value, 1);
66 static void sftp_pkt_adduint32(struct sftp_packet *pkt, unsigned long value) {
69 sftp_pkt_adddata(pkt, x, 4);
71 static void sftp_pkt_adduint64(struct sftp_packet *pkt, uint64 value) {
73 PUT_32BIT(x, value.hi);
74 PUT_32BIT(x+4, value.lo);
75 sftp_pkt_adddata(pkt, x, 8);
77 static void sftp_pkt_addstring_start(struct sftp_packet *pkt) {
78 sftp_pkt_adduint32(pkt, 0);
79 pkt->savedpos = pkt->length;
81 static void sftp_pkt_addstring_str(struct sftp_packet *pkt, char *data) {
82 sftp_pkt_adddata(pkt, data, strlen(data));
83 PUT_32BIT(pkt->data + pkt->savedpos - 4,
84 pkt->length - pkt->savedpos);
86 static void sftp_pkt_addstring_data(struct sftp_packet *pkt,
87 char *data, int len) {
88 sftp_pkt_adddata(pkt, data, len);
89 PUT_32BIT(pkt->data + pkt->savedpos - 4,
90 pkt->length - pkt->savedpos);
92 static void sftp_pkt_addstring(struct sftp_packet *pkt, char *data) {
93 sftp_pkt_addstring_start(pkt);
94 sftp_pkt_addstring_str(pkt, data);
97 /* ----------------------------------------------------------------------
98 * SFTP packet decode functions.
101 static unsigned char sftp_pkt_getbyte(struct sftp_packet *pkt) {
103 if (pkt->length - pkt->savedpos < 1)
104 return 0; /* arrgh, no way to decline (FIXME?) */
105 value = (unsigned char) pkt->data[pkt->savedpos];
109 static unsigned long sftp_pkt_getuint32(struct sftp_packet *pkt) {
111 if (pkt->length - pkt->savedpos < 4)
112 return 0; /* arrgh, no way to decline (FIXME?) */
113 value = GET_32BIT(pkt->data+pkt->savedpos);
117 static void sftp_pkt_getstring(struct sftp_packet *pkt,
118 char **p, int *length) {
120 if (pkt->length - pkt->savedpos < 4)
122 *length = GET_32BIT(pkt->data+pkt->savedpos);
124 if (pkt->length - pkt->savedpos < *length)
126 *p = pkt->data+pkt->savedpos;
127 pkt->savedpos += *length;
129 static struct fxp_attrs sftp_pkt_getattrs(struct sftp_packet *pkt) {
130 struct fxp_attrs ret;
131 ret.flags = sftp_pkt_getuint32(pkt);
132 if (ret.flags & SSH_FILEXFER_ATTR_SIZE) {
133 unsigned long hi, lo;
134 hi = sftp_pkt_getuint32(pkt);
135 lo = sftp_pkt_getuint32(pkt);
136 ret.size = uint64_make(hi, lo);
138 if (ret.flags & SSH_FILEXFER_ATTR_UIDGID) {
139 ret.uid = sftp_pkt_getuint32(pkt);
140 ret.gid = sftp_pkt_getuint32(pkt);
142 if (ret.flags & SSH_FILEXFER_ATTR_PERMISSIONS) {
143 ret.permissions = sftp_pkt_getuint32(pkt);
145 if (ret.flags & SSH_FILEXFER_ATTR_ACMODTIME) {
146 ret.atime = sftp_pkt_getuint32(pkt);
147 ret.mtime = sftp_pkt_getuint32(pkt);
149 if (ret.flags & SSH_FILEXFER_ATTR_EXTENDED) {
151 count = sftp_pkt_getuint32(pkt);
156 * We should try to analyse these, if we ever find one
159 sftp_pkt_getstring(pkt, &str, &len);
160 sftp_pkt_getstring(pkt, &str, &len);
165 static void sftp_pkt_free(struct sftp_packet *pkt) {
166 if (pkt->data) sfree(pkt->data);
170 /* ----------------------------------------------------------------------
171 * Send and receive packet functions.
173 int sftp_send(struct sftp_packet *pkt) {
176 PUT_32BIT(x, pkt->length);
177 ret = (sftp_senddata(x, 4) &&
178 sftp_senddata(pkt->data, pkt->length));
182 struct sftp_packet *sftp_recv(void) {
183 struct sftp_packet *pkt;
186 if (!sftp_recvdata(x, 4))
189 pkt = smalloc(sizeof(struct sftp_packet));
191 pkt->length = pkt->maxlen = GET_32BIT(x);
192 pkt->data = smalloc(pkt->length);
194 if (!sftp_recvdata(pkt->data, pkt->length)) {
199 pkt->type = sftp_pkt_getbyte(pkt);
204 /* ----------------------------------------------------------------------
205 * String handling routines.
208 static char *mkstr(char *s, int len) {
209 char *p = smalloc(len+1);
215 /* ----------------------------------------------------------------------
219 static const char *fxp_error_message;
220 static int fxp_errtype;
223 * Deal with (and free) an FXP_STATUS packet. Return 1 if
224 * SSH_FX_OK, 0 if SSH_FX_EOF, and -1 for anything else (error).
225 * Also place the status into fxp_errtype.
227 static int fxp_got_status(struct sftp_packet *pktin) {
228 static const char *const messages[] = {
229 /* SSH_FX_OK. The only time we will display a _message_ for this
230 * is if we were expecting something other than FXP_STATUS on
231 * success, so this is actually an error message! */
232 "unexpected OK response",
234 "no such file or directory",
240 "operation unsupported",
243 if (pktin->type != SSH_FXP_STATUS) {
244 fxp_error_message = "expected FXP_STATUS packet";
247 fxp_errtype = sftp_pkt_getuint32(pktin);
248 if (fxp_errtype < 0 ||
249 fxp_errtype >= sizeof(messages)/sizeof(*messages))
250 fxp_error_message = "unknown error code";
252 fxp_error_message = messages[fxp_errtype];
255 if (fxp_errtype == SSH_FX_OK)
257 else if (fxp_errtype == SSH_FX_EOF)
263 static void fxp_internal_error(char *msg) {
264 fxp_error_message = msg;
268 const char *fxp_error(void) {
269 return fxp_error_message;
272 int fxp_error_type(void) {
277 * Perform exchange of init/version packets. Return 0 on failure.
280 struct sftp_packet *pktout, *pktin;
283 pktout = sftp_pkt_init(SSH_FXP_INIT);
284 sftp_pkt_adduint32(pktout, SFTP_PROTO_VERSION);
289 fxp_internal_error("could not connect");
292 if (pktin->type != SSH_FXP_VERSION) {
293 fxp_internal_error("did not receive FXP_VERSION");
296 remotever = sftp_pkt_getuint32(pktin);
297 if (remotever > SFTP_PROTO_VERSION) {
298 fxp_internal_error("remote protocol is more advanced than we support");
302 * In principle, this packet might also contain extension-
303 * string pairs. We should work through them and look for any
304 * we recognise. In practice we don't currently do so because
305 * we know we don't recognise _any_.
307 sftp_pkt_free(pktin);
313 * Canonify a pathname.
315 char *fxp_realpath(char *path) {
316 struct sftp_packet *pktin, *pktout;
319 pktout = sftp_pkt_init(SSH_FXP_REALPATH);
320 sftp_pkt_adduint32(pktout, 0x123); /* request id */
321 sftp_pkt_addstring_start(pktout);
322 sftp_pkt_addstring_str(pktout, path);
325 id = sftp_pkt_getuint32(pktin);
327 fxp_internal_error("request ID mismatch\n");
330 if (pktin->type == SSH_FXP_NAME) {
335 count = sftp_pkt_getuint32(pktin);
337 fxp_internal_error("REALPATH returned name count != 1\n");
340 sftp_pkt_getstring(pktin, &path, &len);
342 fxp_internal_error("REALPATH returned malformed FXP_NAME\n");
345 path = mkstr(path, len);
346 sftp_pkt_free(pktin);
349 fxp_got_status(pktin);
357 struct fxp_handle *fxp_open(char *path, int type) {
358 struct sftp_packet *pktin, *pktout;
361 pktout = sftp_pkt_init(SSH_FXP_OPEN);
362 sftp_pkt_adduint32(pktout, 0x567); /* request id */
363 sftp_pkt_addstring(pktout, path);
364 sftp_pkt_adduint32(pktout, type);
365 sftp_pkt_adduint32(pktout, 0); /* (FIXME) empty ATTRS structure */
368 id = sftp_pkt_getuint32(pktin);
370 fxp_internal_error("request ID mismatch\n");
373 if (pktin->type == SSH_FXP_HANDLE) {
375 struct fxp_handle *handle;
378 sftp_pkt_getstring(pktin, &hstring, &len);
380 fxp_internal_error("OPEN returned malformed FXP_HANDLE\n");
383 handle = smalloc(sizeof(struct fxp_handle));
384 handle->hstring = mkstr(hstring, len);
386 sftp_pkt_free(pktin);
389 fxp_got_status(pktin);
397 struct fxp_handle *fxp_opendir(char *path) {
398 struct sftp_packet *pktin, *pktout;
401 pktout = sftp_pkt_init(SSH_FXP_OPENDIR);
402 sftp_pkt_adduint32(pktout, 0x456); /* request id */
403 sftp_pkt_addstring(pktout, path);
406 id = sftp_pkt_getuint32(pktin);
408 fxp_internal_error("request ID mismatch\n");
411 if (pktin->type == SSH_FXP_HANDLE) {
413 struct fxp_handle *handle;
416 sftp_pkt_getstring(pktin, &hstring, &len);
418 fxp_internal_error("OPENDIR returned malformed FXP_HANDLE\n");
421 handle = smalloc(sizeof(struct fxp_handle));
422 handle->hstring = mkstr(hstring, len);
424 sftp_pkt_free(pktin);
427 fxp_got_status(pktin);
435 void fxp_close(struct fxp_handle *handle) {
436 struct sftp_packet *pktin, *pktout;
439 pktout = sftp_pkt_init(SSH_FXP_CLOSE);
440 sftp_pkt_adduint32(pktout, 0x789); /* request id */
441 sftp_pkt_addstring_start(pktout);
442 sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen);
445 id = sftp_pkt_getuint32(pktin);
447 fxp_internal_error("request ID mismatch\n");
450 fxp_got_status(pktin);
451 sfree(handle->hstring);
456 * Read from a file. Returns the number of bytes read, or -1 on an
457 * error, or possibly 0 if EOF. (I'm not entirely sure whether it
458 * will return 0 on EOF, or return -1 and store SSH_FX_EOF in the
459 * error indicator. It might even depend on the SFTP server.)
461 int fxp_read(struct fxp_handle *handle, char *buffer, uint64 offset, int len) {
462 struct sftp_packet *pktin, *pktout;
465 pktout = sftp_pkt_init(SSH_FXP_READ);
466 sftp_pkt_adduint32(pktout, 0xBCD); /* request id */
467 sftp_pkt_addstring_start(pktout);
468 sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen);
469 sftp_pkt_adduint64(pktout, offset);
470 sftp_pkt_adduint32(pktout, len);
473 id = sftp_pkt_getuint32(pktin);
475 fxp_internal_error("request ID mismatch");
478 if (pktin->type == SSH_FXP_DATA) {
482 sftp_pkt_getstring(pktin, &str, &rlen);
484 if (rlen > len || rlen < 0) {
485 fxp_internal_error("READ returned more bytes than requested");
489 memcpy(buffer, str, rlen);
493 fxp_got_status(pktin);
499 * Read from a directory.
501 struct fxp_names *fxp_readdir(struct fxp_handle *handle) {
502 struct sftp_packet *pktin, *pktout;
505 pktout = sftp_pkt_init(SSH_FXP_READDIR);
506 sftp_pkt_adduint32(pktout, 0xABC); /* request id */
507 sftp_pkt_addstring_start(pktout);
508 sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen);
511 id = sftp_pkt_getuint32(pktin);
513 fxp_internal_error("request ID mismatch\n");
516 if (pktin->type == SSH_FXP_NAME) {
517 struct fxp_names *ret;
519 ret = smalloc(sizeof(struct fxp_names));
520 ret->nnames = sftp_pkt_getuint32(pktin);
521 ret->names = smalloc(ret->nnames * sizeof(struct fxp_name));
522 for (i = 0; i < ret->nnames; i++) {
525 sftp_pkt_getstring(pktin, &str, &len);
526 ret->names[i].filename = mkstr(str, len);
527 sftp_pkt_getstring(pktin, &str, &len);
528 ret->names[i].longname = mkstr(str, len);
529 ret->names[i].attrs = sftp_pkt_getattrs(pktin);
533 fxp_got_status(pktin);
539 * Write to a file. Returns 0 on error, 1 on OK.
541 int fxp_write(struct fxp_handle *handle, char *buffer, uint64 offset, int len) {
542 struct sftp_packet *pktin, *pktout;
545 pktout = sftp_pkt_init(SSH_FXP_WRITE);
546 sftp_pkt_adduint32(pktout, 0xDCB); /* request id */
547 sftp_pkt_addstring_start(pktout);
548 sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen);
549 sftp_pkt_adduint64(pktout, offset);
550 sftp_pkt_addstring_start(pktout);
551 sftp_pkt_addstring_data(pktout, buffer, len);
554 id = sftp_pkt_getuint32(pktin);
556 fxp_internal_error("request ID mismatch\n");
559 fxp_got_status(pktin);
560 return fxp_errtype == SSH_FX_OK;
564 * Free up an fxp_names structure.
566 void fxp_free_names(struct fxp_names *names) {
569 for (i = 0; i < names->nnames; i++) {
570 sfree(names->names[i].filename);
571 sfree(names->names[i].longname);