4c7f0d61 |
1 | /* |
2 | * sftp.c: SFTP generic client code. |
3 | */ |
4 | |
5 | #include <stdio.h> |
6 | #include <stdlib.h> |
4a8fc3c4 |
7 | #include <string.h> |
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8 | #include <assert.h> |
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9 | |
10 | #include "int64.h" |
11 | #include "sftp.h" |
12 | |
13 | #define smalloc malloc |
14 | #define srealloc realloc |
15 | #define sfree free |
16 | |
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])) |
22 | |
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); } |
28 | |
29 | struct sftp_packet { |
30 | char *data; |
31 | int length, maxlen; |
32 | int savedpos; |
33 | int type; |
34 | }; |
35 | |
36 | /* ---------------------------------------------------------------------- |
37 | * SFTP packet construction functions. |
38 | */ |
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); |
43 | } |
44 | } |
45 | static void sftp_pkt_adddata(struct sftp_packet *pkt, void *data, int len) { |
46 | pkt->length += len; |
47 | sftp_pkt_ensure(pkt, pkt->length); |
48 | memcpy(pkt->data+pkt->length-len, data, len); |
49 | } |
50 | static void sftp_pkt_addbyte(struct sftp_packet *pkt, unsigned char byte) { |
51 | sftp_pkt_adddata(pkt, &byte, 1); |
52 | } |
53 | static struct sftp_packet *sftp_pkt_init(int pkt_type) { |
54 | struct sftp_packet *pkt; |
55 | pkt = smalloc(sizeof(struct sftp_packet)); |
56 | pkt->data = NULL; |
57 | pkt->savedpos = -1; |
58 | pkt->length = 0; |
59 | pkt->maxlen = 0; |
60 | sftp_pkt_addbyte(pkt, (unsigned char)pkt_type); |
61 | return pkt; |
62 | } |
63 | static void sftp_pkt_addbool(struct sftp_packet *pkt, unsigned char value) { |
64 | sftp_pkt_adddata(pkt, &value, 1); |
65 | } |
66 | static void sftp_pkt_adduint32(struct sftp_packet *pkt, unsigned long value) { |
67 | unsigned char x[4]; |
68 | PUT_32BIT(x, value); |
69 | sftp_pkt_adddata(pkt, x, 4); |
70 | } |
71 | static void sftp_pkt_adduint64(struct sftp_packet *pkt, uint64 value) { |
72 | unsigned char x[8]; |
73 | PUT_32BIT(x, value.hi); |
74 | PUT_32BIT(x+4, value.lo); |
75 | sftp_pkt_adddata(pkt, x, 8); |
76 | } |
77 | static void sftp_pkt_addstring_start(struct sftp_packet *pkt) { |
78 | sftp_pkt_adduint32(pkt, 0); |
79 | pkt->savedpos = pkt->length; |
80 | } |
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); |
85 | } |
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); |
91 | } |
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); |
95 | } |
96 | |
97 | /* ---------------------------------------------------------------------- |
98 | * SFTP packet decode functions. |
99 | */ |
100 | |
101 | static unsigned char sftp_pkt_getbyte(struct sftp_packet *pkt) { |
102 | unsigned long value; |
103 | if (pkt->length - pkt->savedpos < 1) |
104 | return 0; /* arrgh, no way to decline (FIXME?) */ |
105 | value = (unsigned char) pkt->data[pkt->savedpos]; |
106 | pkt->savedpos++; |
107 | return value; |
108 | } |
109 | static unsigned long sftp_pkt_getuint32(struct sftp_packet *pkt) { |
110 | unsigned long value; |
111 | if (pkt->length - pkt->savedpos < 4) |
112 | return 0; /* arrgh, no way to decline (FIXME?) */ |
113 | value = GET_32BIT(pkt->data+pkt->savedpos); |
114 | pkt->savedpos += 4; |
115 | return value; |
116 | } |
117 | static void sftp_pkt_getstring(struct sftp_packet *pkt, |
118 | char **p, int *length) { |
119 | *p = NULL; |
120 | if (pkt->length - pkt->savedpos < 4) |
121 | return; |
122 | *length = GET_32BIT(pkt->data+pkt->savedpos); |
123 | pkt->savedpos += 4; |
124 | if (pkt->length - pkt->savedpos < *length) |
125 | return; |
126 | *p = pkt->data+pkt->savedpos; |
127 | pkt->savedpos += *length; |
128 | } |
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); |
137 | } |
138 | if (ret.flags & SSH_FILEXFER_ATTR_UIDGID) { |
139 | ret.uid = sftp_pkt_getuint32(pkt); |
140 | ret.gid = sftp_pkt_getuint32(pkt); |
141 | } |
142 | if (ret.flags & SSH_FILEXFER_ATTR_PERMISSIONS) { |
143 | ret.permissions = sftp_pkt_getuint32(pkt); |
144 | } |
145 | if (ret.flags & SSH_FILEXFER_ATTR_ACMODTIME) { |
146 | ret.atime = sftp_pkt_getuint32(pkt); |
147 | ret.mtime = sftp_pkt_getuint32(pkt); |
148 | } |
149 | if (ret.flags & SSH_FILEXFER_ATTR_EXTENDED) { |
150 | int count; |
151 | count = sftp_pkt_getuint32(pkt); |
152 | while (count--) { |
153 | char *str; |
154 | int len; |
155 | /* |
156 | * We should try to analyse these, if we ever find one |
157 | * we recognise. |
158 | */ |
159 | sftp_pkt_getstring(pkt, &str, &len); |
160 | sftp_pkt_getstring(pkt, &str, &len); |
161 | } |
162 | } |
163 | return ret; |
164 | } |
165 | static void sftp_pkt_free(struct sftp_packet *pkt) { |
166 | if (pkt->data) sfree(pkt->data); |
167 | sfree(pkt); |
168 | } |
169 | |
170 | /* ---------------------------------------------------------------------- |
4a8fc3c4 |
171 | * Send and receive packet functions. |
4c7f0d61 |
172 | */ |
4c7f0d61 |
173 | int sftp_send(struct sftp_packet *pkt) { |
4a8fc3c4 |
174 | int ret; |
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175 | char x[4]; |
176 | PUT_32BIT(x, pkt->length); |
4a8fc3c4 |
177 | ret = (sftp_senddata(x, 4) && |
178 | sftp_senddata(pkt->data, pkt->length)); |
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179 | sftp_pkt_free(pkt); |
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180 | return ret; |
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181 | } |
182 | struct sftp_packet *sftp_recv(void) { |
183 | struct sftp_packet *pkt; |
184 | char x[4]; |
185 | int p, ret; |
186 | |
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187 | if (!sftp_recvdata(x, 4)) |
188 | return NULL; |
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189 | |
190 | pkt = smalloc(sizeof(struct sftp_packet)); |
191 | pkt->savedpos = 0; |
192 | pkt->length = pkt->maxlen = GET_32BIT(x); |
193 | pkt->data = smalloc(pkt->length); |
194 | |
4a8fc3c4 |
195 | if (!sftp_recvdata(pkt->data, pkt->length)) { |
196 | sftp_pkt_free(pkt); |
197 | return NULL; |
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198 | } |
199 | |
200 | pkt->type = sftp_pkt_getbyte(pkt); |
201 | |
202 | return pkt; |
203 | } |
204 | |
205 | /* ---------------------------------------------------------------------- |
206 | * String handling routines. |
207 | */ |
208 | |
209 | static char *mkstr(char *s, int len) { |
210 | char *p = smalloc(len+1); |
211 | memcpy(p, s, len); |
212 | p[len] = '\0'; |
213 | return p; |
214 | } |
215 | |
216 | /* ---------------------------------------------------------------------- |
217 | * SFTP primitives. |
218 | */ |
219 | |
220 | static const char *fxp_error_message; |
221 | static int fxp_errtype; |
222 | |
223 | /* |
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. |
227 | */ |
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", |
234 | "end of file", |
235 | "no such file or directory", |
236 | "permission denied", |
237 | "failure", |
238 | "bad message", |
239 | "no connection", |
240 | "connection lost", |
241 | "operation unsupported", |
242 | }; |
243 | |
244 | if (pktin->type != SSH_FXP_STATUS) { |
245 | fxp_error_message = "expected FXP_STATUS packet"; |
246 | fxp_errtype = -1; |
247 | } else { |
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"; |
252 | else |
253 | fxp_error_message = messages[fxp_errtype]; |
254 | } |
255 | |
256 | if (fxp_errtype == SSH_FX_OK) |
257 | return 1; |
258 | else if (fxp_errtype == SSH_FX_EOF) |
259 | return 0; |
260 | else |
261 | return -1; |
262 | } |
263 | |
4a8fc3c4 |
264 | static void fxp_internal_error(char *msg) { |
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265 | fxp_error_message = msg; |
266 | fxp_errtype = -1; |
267 | } |
268 | |
269 | const char *fxp_error(void) { |
270 | return fxp_error_message; |
271 | } |
272 | |
273 | int fxp_error_type(void) { |
274 | return fxp_errtype; |
275 | } |
276 | |
277 | /* |
278 | * Perform exchange of init/version packets. Return 0 on failure. |
279 | */ |
280 | int fxp_init(void) { |
281 | struct sftp_packet *pktout, *pktin; |
282 | int remotever; |
283 | |
284 | pktout = sftp_pkt_init(SSH_FXP_INIT); |
285 | sftp_pkt_adduint32(pktout, SFTP_PROTO_VERSION); |
286 | sftp_send(pktout); |
287 | |
288 | pktin = sftp_recv(); |
0d694692 |
289 | if (!pktin) { |
290 | fxp_internal_error("could not connect"); |
291 | return 0; |
292 | } |
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293 | if (pktin->type != SSH_FXP_VERSION) { |
294 | fxp_internal_error("did not receive FXP_VERSION"); |
295 | return 0; |
296 | } |
297 | remotever = sftp_pkt_getuint32(pktin); |
298 | if (remotever > SFTP_PROTO_VERSION) { |
299 | fxp_internal_error("remote protocol is more advanced than we support"); |
300 | return 0; |
301 | } |
302 | /* |
303 | * In principle, this packet might also contain extension- |
304 | * string pairs. We should work through them and look for any |
305 | * we recognise. In practice we don't currently do so because |
306 | * we know we don't recognise _any_. |
307 | */ |
308 | sftp_pkt_free(pktin); |
309 | |
310 | return 1; |
311 | } |
312 | |
313 | /* |
f9e162aa |
314 | * Canonify a pathname. |
4c7f0d61 |
315 | */ |
f9e162aa |
316 | char *fxp_realpath(char *path) { |
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317 | struct sftp_packet *pktin, *pktout; |
318 | int id; |
319 | |
320 | pktout = sftp_pkt_init(SSH_FXP_REALPATH); |
321 | sftp_pkt_adduint32(pktout, 0x123); /* request id */ |
322 | sftp_pkt_addstring_start(pktout); |
323 | sftp_pkt_addstring_str(pktout, path); |
4c7f0d61 |
324 | sftp_send(pktout); |
325 | pktin = sftp_recv(); |
326 | id = sftp_pkt_getuint32(pktin); |
327 | if (id != 0x123) { |
328 | fxp_internal_error("request ID mismatch\n"); |
329 | return NULL; |
330 | } |
331 | if (pktin->type == SSH_FXP_NAME) { |
332 | int count; |
333 | char *path; |
334 | int len; |
335 | |
336 | count = sftp_pkt_getuint32(pktin); |
337 | if (count != 1) { |
338 | fxp_internal_error("REALPATH returned name count != 1\n"); |
339 | return NULL; |
340 | } |
341 | sftp_pkt_getstring(pktin, &path, &len); |
342 | if (!path) { |
343 | fxp_internal_error("REALPATH returned malformed FXP_NAME\n"); |
344 | return NULL; |
345 | } |
346 | path = mkstr(path, len); |
347 | sftp_pkt_free(pktin); |
348 | return path; |
349 | } else { |
350 | fxp_got_status(pktin); |
351 | return NULL; |
352 | } |
353 | } |
354 | |
355 | /* |
356 | * Open a file. |
357 | */ |
358 | struct fxp_handle *fxp_open(char *path, int type) { |
359 | struct sftp_packet *pktin, *pktout; |
360 | int id; |
361 | |
362 | pktout = sftp_pkt_init(SSH_FXP_OPEN); |
363 | sftp_pkt_adduint32(pktout, 0x567); /* request id */ |
364 | sftp_pkt_addstring(pktout, path); |
365 | sftp_pkt_adduint32(pktout, type); |
366 | sftp_pkt_adduint32(pktout, 0); /* (FIXME) empty ATTRS structure */ |
367 | sftp_send(pktout); |
368 | pktin = sftp_recv(); |
369 | id = sftp_pkt_getuint32(pktin); |
370 | if (id != 0x567) { |
371 | fxp_internal_error("request ID mismatch\n"); |
372 | return NULL; |
373 | } |
374 | if (pktin->type == SSH_FXP_HANDLE) { |
375 | int count; |
376 | char *hstring; |
377 | struct fxp_handle *handle; |
378 | int len; |
379 | |
380 | sftp_pkt_getstring(pktin, &hstring, &len); |
381 | if (!hstring) { |
382 | fxp_internal_error("OPEN returned malformed FXP_HANDLE\n"); |
383 | return NULL; |
384 | } |
385 | handle = smalloc(sizeof(struct fxp_handle)); |
386 | handle->hstring = mkstr(hstring, len); |
f9e162aa |
387 | handle->hlen = len; |
4c7f0d61 |
388 | sftp_pkt_free(pktin); |
389 | return handle; |
390 | } else { |
391 | fxp_got_status(pktin); |
392 | return NULL; |
393 | } |
394 | } |
395 | |
396 | /* |
397 | * Open a directory. |
398 | */ |
399 | struct fxp_handle *fxp_opendir(char *path) { |
400 | struct sftp_packet *pktin, *pktout; |
401 | int id; |
402 | |
403 | pktout = sftp_pkt_init(SSH_FXP_OPENDIR); |
404 | sftp_pkt_adduint32(pktout, 0x456); /* request id */ |
405 | sftp_pkt_addstring(pktout, path); |
406 | sftp_send(pktout); |
407 | pktin = sftp_recv(); |
408 | id = sftp_pkt_getuint32(pktin); |
409 | if (id != 0x456) { |
410 | fxp_internal_error("request ID mismatch\n"); |
411 | return NULL; |
412 | } |
413 | if (pktin->type == SSH_FXP_HANDLE) { |
414 | int count; |
415 | char *hstring; |
416 | struct fxp_handle *handle; |
417 | int len; |
418 | |
419 | sftp_pkt_getstring(pktin, &hstring, &len); |
420 | if (!hstring) { |
421 | fxp_internal_error("OPENDIR returned malformed FXP_HANDLE\n"); |
422 | return NULL; |
423 | } |
424 | handle = smalloc(sizeof(struct fxp_handle)); |
425 | handle->hstring = mkstr(hstring, len); |
f9e162aa |
426 | handle->hlen = len; |
4c7f0d61 |
427 | sftp_pkt_free(pktin); |
428 | return handle; |
429 | } else { |
430 | fxp_got_status(pktin); |
431 | return NULL; |
432 | } |
433 | } |
434 | |
435 | /* |
436 | * Close a file/dir. |
437 | */ |
438 | void fxp_close(struct fxp_handle *handle) { |
439 | struct sftp_packet *pktin, *pktout; |
440 | int id; |
441 | |
442 | pktout = sftp_pkt_init(SSH_FXP_CLOSE); |
443 | sftp_pkt_adduint32(pktout, 0x789); /* request id */ |
f9e162aa |
444 | sftp_pkt_addstring_start(pktout); |
445 | sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen); |
4c7f0d61 |
446 | sftp_send(pktout); |
447 | pktin = sftp_recv(); |
448 | id = sftp_pkt_getuint32(pktin); |
449 | if (id != 0x789) { |
450 | fxp_internal_error("request ID mismatch\n"); |
451 | return; |
452 | } |
453 | fxp_got_status(pktin); |
454 | sfree(handle->hstring); |
455 | sfree(handle); |
456 | } |
457 | |
458 | /* |
459 | * Read from a file. Returns the number of bytes read, or -1 on an |
460 | * error, or possibly 0 if EOF. (I'm not entirely sure whether it |
461 | * will return 0 on EOF, or return -1 and store SSH_FX_EOF in the |
462 | * error indicator. It might even depend on the SFTP server.) |
463 | */ |
464 | int fxp_read(struct fxp_handle *handle, char *buffer, uint64 offset, int len) { |
465 | struct sftp_packet *pktin, *pktout; |
466 | int id; |
467 | |
468 | pktout = sftp_pkt_init(SSH_FXP_READ); |
469 | sftp_pkt_adduint32(pktout, 0xBCD); /* request id */ |
f9e162aa |
470 | sftp_pkt_addstring_start(pktout); |
471 | sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen); |
4c7f0d61 |
472 | sftp_pkt_adduint64(pktout, offset); |
473 | sftp_pkt_adduint32(pktout, len); |
474 | sftp_send(pktout); |
475 | pktin = sftp_recv(); |
476 | id = sftp_pkt_getuint32(pktin); |
477 | if (id != 0xBCD) { |
478 | fxp_internal_error("request ID mismatch"); |
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479 | return -1; |
4c7f0d61 |
480 | } |
481 | if (pktin->type == SSH_FXP_DATA) { |
482 | char *str; |
483 | int rlen; |
484 | |
485 | sftp_pkt_getstring(pktin, &str, &rlen); |
486 | |
487 | if (rlen > len || rlen < 0) { |
488 | fxp_internal_error("READ returned more bytes than requested"); |
489 | return -1; |
490 | } |
491 | |
492 | memcpy(buffer, str, rlen); |
493 | sfree(pktin); |
494 | return rlen; |
495 | } else { |
496 | fxp_got_status(pktin); |
497 | return -1; |
498 | } |
499 | } |
500 | |
501 | /* |
502 | * Read from a directory. |
503 | */ |
504 | struct fxp_names *fxp_readdir(struct fxp_handle *handle) { |
505 | struct sftp_packet *pktin, *pktout; |
506 | int id; |
507 | |
508 | pktout = sftp_pkt_init(SSH_FXP_READDIR); |
509 | sftp_pkt_adduint32(pktout, 0xABC); /* request id */ |
f9e162aa |
510 | sftp_pkt_addstring_start(pktout); |
511 | sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen); |
4c7f0d61 |
512 | sftp_send(pktout); |
513 | pktin = sftp_recv(); |
514 | id = sftp_pkt_getuint32(pktin); |
515 | if (id != 0xABC) { |
516 | fxp_internal_error("request ID mismatch\n"); |
4a8fc3c4 |
517 | return NULL; |
4c7f0d61 |
518 | } |
519 | if (pktin->type == SSH_FXP_NAME) { |
520 | struct fxp_names *ret; |
521 | int i; |
522 | ret = smalloc(sizeof(struct fxp_names)); |
523 | ret->nnames = sftp_pkt_getuint32(pktin); |
524 | ret->names = smalloc(ret->nnames * sizeof(struct fxp_name)); |
525 | for (i = 0; i < ret->nnames; i++) { |
526 | char *str; |
527 | int len; |
528 | sftp_pkt_getstring(pktin, &str, &len); |
529 | ret->names[i].filename = mkstr(str, len); |
530 | sftp_pkt_getstring(pktin, &str, &len); |
531 | ret->names[i].longname = mkstr(str, len); |
532 | ret->names[i].attrs = sftp_pkt_getattrs(pktin); |
533 | } |
534 | return ret; |
535 | } else { |
536 | fxp_got_status(pktin); |
537 | return NULL; |
538 | } |
539 | } |
540 | |
541 | /* |
542 | * Write to a file. Returns 0 on error, 1 on OK. |
543 | */ |
544 | int fxp_write(struct fxp_handle *handle, char *buffer, uint64 offset, int len) { |
545 | struct sftp_packet *pktin, *pktout; |
546 | int id; |
547 | |
548 | pktout = sftp_pkt_init(SSH_FXP_WRITE); |
549 | sftp_pkt_adduint32(pktout, 0xDCB); /* request id */ |
f9e162aa |
550 | sftp_pkt_addstring_start(pktout); |
551 | sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen); |
4c7f0d61 |
552 | sftp_pkt_adduint64(pktout, offset); |
553 | sftp_pkt_addstring_start(pktout); |
554 | sftp_pkt_addstring_data(pktout, buffer, len); |
555 | sftp_send(pktout); |
556 | pktin = sftp_recv(); |
557 | id = sftp_pkt_getuint32(pktin); |
4a8fc3c4 |
558 | if (id != 0xDCB) { |
559 | fxp_internal_error("request ID mismatch\n"); |
560 | return NULL; |
561 | } |
4c7f0d61 |
562 | fxp_got_status(pktin); |
563 | return fxp_errtype == SSH_FX_OK; |
564 | } |
565 | |
566 | /* |
567 | * Free up an fxp_names structure. |
568 | */ |
569 | void fxp_free_names(struct fxp_names *names) { |
570 | int i; |
571 | |
572 | for (i = 0; i < names->nnames; i++) { |
573 | sfree(names->names[i].filename); |
574 | sfree(names->names[i].longname); |
575 | } |
576 | sfree(names->names); |
577 | sfree(names); |
578 | } |