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;
187 if (!sftp_recvdata(x, 4))
190 pkt = smalloc(sizeof(struct sftp_packet));
192 pkt->length = pkt->maxlen = GET_32BIT(x);
193 pkt->data = smalloc(pkt->length);
195 if (!sftp_recvdata(pkt->data, pkt->length)) {
200 pkt->type = sftp_pkt_getbyte(pkt);
205 /* ----------------------------------------------------------------------
206 * String handling routines.
209 static char *mkstr(char *s, int len) {
210 char *p = smalloc(len+1);
216 /* ----------------------------------------------------------------------
220 static const char *fxp_error_message;
221 static int fxp_errtype;
224 * Deal with (and free) an FXP_STATUS packet. Return 1 if
225 * SSH_FX_OK, 0 if SSH_FX_EOF, and -1 for anything else (error).
226 * Also place the status into fxp_errtype.
228 static int fxp_got_status(struct sftp_packet *pktin) {
229 static const char *const messages[] = {
230 /* SSH_FX_OK. The only time we will display a _message_ for this
231 * is if we were expecting something other than FXP_STATUS on
232 * success, so this is actually an error message! */
233 "unexpected OK response",
235 "no such file or directory",
241 "operation unsupported",
244 if (pktin->type != SSH_FXP_STATUS) {
245 fxp_error_message = "expected FXP_STATUS packet";
248 fxp_errtype = sftp_pkt_getuint32(pktin);
249 if (fxp_errtype < 0 ||
250 fxp_errtype >= sizeof(messages)/sizeof(*messages))
251 fxp_error_message = "unknown error code";
253 fxp_error_message = messages[fxp_errtype];
256 if (fxp_errtype == SSH_FX_OK)
258 else if (fxp_errtype == SSH_FX_EOF)
264 static void fxp_internal_error(char *msg) {
265 fxp_error_message = msg;
269 const char *fxp_error(void) {
270 return fxp_error_message;
273 int fxp_error_type(void) {
278 * Perform exchange of init/version packets. Return 0 on failure.
281 struct sftp_packet *pktout, *pktin;
284 pktout = sftp_pkt_init(SSH_FXP_INIT);
285 sftp_pkt_adduint32(pktout, SFTP_PROTO_VERSION);
289 if (pktin->type != SSH_FXP_VERSION) {
290 fxp_internal_error("did not receive FXP_VERSION");
293 remotever = sftp_pkt_getuint32(pktin);
294 if (remotever > SFTP_PROTO_VERSION) {
295 fxp_internal_error("remote protocol is more advanced than we support");
299 * In principle, this packet might also contain extension-
300 * string pairs. We should work through them and look for any
301 * we recognise. In practice we don't currently do so because
302 * we know we don't recognise _any_.
304 sftp_pkt_free(pktin);
310 * Canonify a pathname.
312 char *fxp_realpath(char *path) {
313 struct sftp_packet *pktin, *pktout;
316 pktout = sftp_pkt_init(SSH_FXP_REALPATH);
317 sftp_pkt_adduint32(pktout, 0x123); /* request id */
318 sftp_pkt_addstring_start(pktout);
319 sftp_pkt_addstring_str(pktout, path);
322 id = sftp_pkt_getuint32(pktin);
324 fxp_internal_error("request ID mismatch\n");
327 if (pktin->type == SSH_FXP_NAME) {
332 count = sftp_pkt_getuint32(pktin);
334 fxp_internal_error("REALPATH returned name count != 1\n");
337 sftp_pkt_getstring(pktin, &path, &len);
339 fxp_internal_error("REALPATH returned malformed FXP_NAME\n");
342 path = mkstr(path, len);
343 sftp_pkt_free(pktin);
346 fxp_got_status(pktin);
354 struct fxp_handle *fxp_open(char *path, int type) {
355 struct sftp_packet *pktin, *pktout;
358 pktout = sftp_pkt_init(SSH_FXP_OPEN);
359 sftp_pkt_adduint32(pktout, 0x567); /* request id */
360 sftp_pkt_addstring(pktout, path);
361 sftp_pkt_adduint32(pktout, type);
362 sftp_pkt_adduint32(pktout, 0); /* (FIXME) empty ATTRS structure */
365 id = sftp_pkt_getuint32(pktin);
367 fxp_internal_error("request ID mismatch\n");
370 if (pktin->type == SSH_FXP_HANDLE) {
373 struct fxp_handle *handle;
376 sftp_pkt_getstring(pktin, &hstring, &len);
378 fxp_internal_error("OPEN returned malformed FXP_HANDLE\n");
381 handle = smalloc(sizeof(struct fxp_handle));
382 handle->hstring = mkstr(hstring, len);
384 sftp_pkt_free(pktin);
387 fxp_got_status(pktin);
395 struct fxp_handle *fxp_opendir(char *path) {
396 struct sftp_packet *pktin, *pktout;
399 pktout = sftp_pkt_init(SSH_FXP_OPENDIR);
400 sftp_pkt_adduint32(pktout, 0x456); /* request id */
401 sftp_pkt_addstring(pktout, path);
404 id = sftp_pkt_getuint32(pktin);
406 fxp_internal_error("request ID mismatch\n");
409 if (pktin->type == SSH_FXP_HANDLE) {
412 struct fxp_handle *handle;
415 sftp_pkt_getstring(pktin, &hstring, &len);
417 fxp_internal_error("OPENDIR returned malformed FXP_HANDLE\n");
420 handle = smalloc(sizeof(struct fxp_handle));
421 handle->hstring = mkstr(hstring, len);
423 sftp_pkt_free(pktin);
426 fxp_got_status(pktin);
434 void fxp_close(struct fxp_handle *handle) {
435 struct sftp_packet *pktin, *pktout;
438 pktout = sftp_pkt_init(SSH_FXP_CLOSE);
439 sftp_pkt_adduint32(pktout, 0x789); /* request id */
440 sftp_pkt_addstring_start(pktout);
441 sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen);
444 id = sftp_pkt_getuint32(pktin);
446 fxp_internal_error("request ID mismatch\n");
449 fxp_got_status(pktin);
450 sfree(handle->hstring);
455 * Read from a file. Returns the number of bytes read, or -1 on an
456 * error, or possibly 0 if EOF. (I'm not entirely sure whether it
457 * will return 0 on EOF, or return -1 and store SSH_FX_EOF in the
458 * error indicator. It might even depend on the SFTP server.)
460 int fxp_read(struct fxp_handle *handle, char *buffer, uint64 offset, int len) {
461 struct sftp_packet *pktin, *pktout;
464 pktout = sftp_pkt_init(SSH_FXP_READ);
465 sftp_pkt_adduint32(pktout, 0xBCD); /* request id */
466 sftp_pkt_addstring_start(pktout);
467 sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen);
468 sftp_pkt_adduint64(pktout, offset);
469 sftp_pkt_adduint32(pktout, len);
472 id = sftp_pkt_getuint32(pktin);
474 fxp_internal_error("request ID mismatch");
477 if (pktin->type == SSH_FXP_DATA) {
481 sftp_pkt_getstring(pktin, &str, &rlen);
483 if (rlen > len || rlen < 0) {
484 fxp_internal_error("READ returned more bytes than requested");
488 memcpy(buffer, str, rlen);
492 fxp_got_status(pktin);
498 * Read from a directory.
500 struct fxp_names *fxp_readdir(struct fxp_handle *handle) {
501 struct sftp_packet *pktin, *pktout;
504 pktout = sftp_pkt_init(SSH_FXP_READDIR);
505 sftp_pkt_adduint32(pktout, 0xABC); /* request id */
506 sftp_pkt_addstring_start(pktout);
507 sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen);
510 id = sftp_pkt_getuint32(pktin);
512 fxp_internal_error("request ID mismatch\n");
515 if (pktin->type == SSH_FXP_NAME) {
516 struct fxp_names *ret;
518 ret = smalloc(sizeof(struct fxp_names));
519 ret->nnames = sftp_pkt_getuint32(pktin);
520 ret->names = smalloc(ret->nnames * sizeof(struct fxp_name));
521 for (i = 0; i < ret->nnames; i++) {
524 sftp_pkt_getstring(pktin, &str, &len);
525 ret->names[i].filename = mkstr(str, len);
526 sftp_pkt_getstring(pktin, &str, &len);
527 ret->names[i].longname = mkstr(str, len);
528 ret->names[i].attrs = sftp_pkt_getattrs(pktin);
532 fxp_got_status(pktin);
538 * Write to a file. Returns 0 on error, 1 on OK.
540 int fxp_write(struct fxp_handle *handle, char *buffer, uint64 offset, int len) {
541 struct sftp_packet *pktin, *pktout;
544 pktout = sftp_pkt_init(SSH_FXP_WRITE);
545 sftp_pkt_adduint32(pktout, 0xDCB); /* request id */
546 sftp_pkt_addstring_start(pktout);
547 sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen);
548 sftp_pkt_adduint64(pktout, offset);
549 sftp_pkt_addstring_start(pktout);
550 sftp_pkt_addstring_data(pktout, buffer, len);
553 id = sftp_pkt_getuint32(pktin);
555 fxp_internal_error("request ID mismatch\n");
558 fxp_got_status(pktin);
559 return fxp_errtype == SSH_FX_OK;
563 * Free up an fxp_names structure.
565 void fxp_free_names(struct fxp_names *names) {
568 for (i = 0; i < names->nnames; i++) {
569 sfree(names->names[i].filename);
570 sfree(names->names[i].longname);