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 | /* ---------------------------------------------------------------------- |
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171 | * Send and receive packet functions. |
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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 | |
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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(); |
289 | if (pktin->type != SSH_FXP_VERSION) { |
290 | fxp_internal_error("did not receive FXP_VERSION"); |
291 | return 0; |
292 | } |
293 | remotever = sftp_pkt_getuint32(pktin); |
294 | if (remotever > SFTP_PROTO_VERSION) { |
295 | fxp_internal_error("remote protocol is more advanced than we support"); |
296 | return 0; |
297 | } |
298 | /* |
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_. |
303 | */ |
304 | sftp_pkt_free(pktin); |
305 | |
306 | return 1; |
307 | } |
308 | |
309 | /* |
f9e162aa |
310 | * Canonify a pathname. |
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311 | */ |
f9e162aa |
312 | char *fxp_realpath(char *path) { |
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313 | struct sftp_packet *pktin, *pktout; |
314 | int id; |
315 | |
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); |
4c7f0d61 |
320 | sftp_send(pktout); |
321 | pktin = sftp_recv(); |
322 | id = sftp_pkt_getuint32(pktin); |
323 | if (id != 0x123) { |
324 | fxp_internal_error("request ID mismatch\n"); |
325 | return NULL; |
326 | } |
327 | if (pktin->type == SSH_FXP_NAME) { |
328 | int count; |
329 | char *path; |
330 | int len; |
331 | |
332 | count = sftp_pkt_getuint32(pktin); |
333 | if (count != 1) { |
334 | fxp_internal_error("REALPATH returned name count != 1\n"); |
335 | return NULL; |
336 | } |
337 | sftp_pkt_getstring(pktin, &path, &len); |
338 | if (!path) { |
339 | fxp_internal_error("REALPATH returned malformed FXP_NAME\n"); |
340 | return NULL; |
341 | } |
342 | path = mkstr(path, len); |
343 | sftp_pkt_free(pktin); |
344 | return path; |
345 | } else { |
346 | fxp_got_status(pktin); |
347 | return NULL; |
348 | } |
349 | } |
350 | |
351 | /* |
352 | * Open a file. |
353 | */ |
354 | struct fxp_handle *fxp_open(char *path, int type) { |
355 | struct sftp_packet *pktin, *pktout; |
356 | int id; |
357 | |
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 */ |
363 | sftp_send(pktout); |
364 | pktin = sftp_recv(); |
365 | id = sftp_pkt_getuint32(pktin); |
366 | if (id != 0x567) { |
367 | fxp_internal_error("request ID mismatch\n"); |
368 | return NULL; |
369 | } |
370 | if (pktin->type == SSH_FXP_HANDLE) { |
371 | int count; |
372 | char *hstring; |
373 | struct fxp_handle *handle; |
374 | int len; |
375 | |
376 | sftp_pkt_getstring(pktin, &hstring, &len); |
377 | if (!hstring) { |
378 | fxp_internal_error("OPEN returned malformed FXP_HANDLE\n"); |
379 | return NULL; |
380 | } |
381 | handle = smalloc(sizeof(struct fxp_handle)); |
382 | handle->hstring = mkstr(hstring, len); |
f9e162aa |
383 | handle->hlen = len; |
4c7f0d61 |
384 | sftp_pkt_free(pktin); |
385 | return handle; |
386 | } else { |
387 | fxp_got_status(pktin); |
388 | return NULL; |
389 | } |
390 | } |
391 | |
392 | /* |
393 | * Open a directory. |
394 | */ |
395 | struct fxp_handle *fxp_opendir(char *path) { |
396 | struct sftp_packet *pktin, *pktout; |
397 | int id; |
398 | |
399 | pktout = sftp_pkt_init(SSH_FXP_OPENDIR); |
400 | sftp_pkt_adduint32(pktout, 0x456); /* request id */ |
401 | sftp_pkt_addstring(pktout, path); |
402 | sftp_send(pktout); |
403 | pktin = sftp_recv(); |
404 | id = sftp_pkt_getuint32(pktin); |
405 | if (id != 0x456) { |
406 | fxp_internal_error("request ID mismatch\n"); |
407 | return NULL; |
408 | } |
409 | if (pktin->type == SSH_FXP_HANDLE) { |
410 | int count; |
411 | char *hstring; |
412 | struct fxp_handle *handle; |
413 | int len; |
414 | |
415 | sftp_pkt_getstring(pktin, &hstring, &len); |
416 | if (!hstring) { |
417 | fxp_internal_error("OPENDIR returned malformed FXP_HANDLE\n"); |
418 | return NULL; |
419 | } |
420 | handle = smalloc(sizeof(struct fxp_handle)); |
421 | handle->hstring = mkstr(hstring, len); |
f9e162aa |
422 | handle->hlen = len; |
4c7f0d61 |
423 | sftp_pkt_free(pktin); |
424 | return handle; |
425 | } else { |
426 | fxp_got_status(pktin); |
427 | return NULL; |
428 | } |
429 | } |
430 | |
431 | /* |
432 | * Close a file/dir. |
433 | */ |
434 | void fxp_close(struct fxp_handle *handle) { |
435 | struct sftp_packet *pktin, *pktout; |
436 | int id; |
437 | |
438 | pktout = sftp_pkt_init(SSH_FXP_CLOSE); |
439 | sftp_pkt_adduint32(pktout, 0x789); /* request id */ |
f9e162aa |
440 | sftp_pkt_addstring_start(pktout); |
441 | sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen); |
4c7f0d61 |
442 | sftp_send(pktout); |
443 | pktin = sftp_recv(); |
444 | id = sftp_pkt_getuint32(pktin); |
445 | if (id != 0x789) { |
446 | fxp_internal_error("request ID mismatch\n"); |
447 | return; |
448 | } |
449 | fxp_got_status(pktin); |
450 | sfree(handle->hstring); |
451 | sfree(handle); |
452 | } |
453 | |
454 | /* |
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.) |
459 | */ |
460 | int fxp_read(struct fxp_handle *handle, char *buffer, uint64 offset, int len) { |
461 | struct sftp_packet *pktin, *pktout; |
462 | int id; |
463 | |
464 | pktout = sftp_pkt_init(SSH_FXP_READ); |
465 | sftp_pkt_adduint32(pktout, 0xBCD); /* request id */ |
f9e162aa |
466 | sftp_pkt_addstring_start(pktout); |
467 | sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen); |
4c7f0d61 |
468 | sftp_pkt_adduint64(pktout, offset); |
469 | sftp_pkt_adduint32(pktout, len); |
470 | sftp_send(pktout); |
471 | pktin = sftp_recv(); |
472 | id = sftp_pkt_getuint32(pktin); |
473 | if (id != 0xBCD) { |
474 | fxp_internal_error("request ID mismatch"); |
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475 | return -1; |
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476 | } |
477 | if (pktin->type == SSH_FXP_DATA) { |
478 | char *str; |
479 | int rlen; |
480 | |
481 | sftp_pkt_getstring(pktin, &str, &rlen); |
482 | |
483 | if (rlen > len || rlen < 0) { |
484 | fxp_internal_error("READ returned more bytes than requested"); |
485 | return -1; |
486 | } |
487 | |
488 | memcpy(buffer, str, rlen); |
489 | sfree(pktin); |
490 | return rlen; |
491 | } else { |
492 | fxp_got_status(pktin); |
493 | return -1; |
494 | } |
495 | } |
496 | |
497 | /* |
498 | * Read from a directory. |
499 | */ |
500 | struct fxp_names *fxp_readdir(struct fxp_handle *handle) { |
501 | struct sftp_packet *pktin, *pktout; |
502 | int id; |
503 | |
504 | pktout = sftp_pkt_init(SSH_FXP_READDIR); |
505 | sftp_pkt_adduint32(pktout, 0xABC); /* request id */ |
f9e162aa |
506 | sftp_pkt_addstring_start(pktout); |
507 | sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen); |
4c7f0d61 |
508 | sftp_send(pktout); |
509 | pktin = sftp_recv(); |
510 | id = sftp_pkt_getuint32(pktin); |
511 | if (id != 0xABC) { |
512 | fxp_internal_error("request ID mismatch\n"); |
4a8fc3c4 |
513 | return NULL; |
4c7f0d61 |
514 | } |
515 | if (pktin->type == SSH_FXP_NAME) { |
516 | struct fxp_names *ret; |
517 | int i; |
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++) { |
522 | char *str; |
523 | int len; |
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); |
529 | } |
530 | return ret; |
531 | } else { |
532 | fxp_got_status(pktin); |
533 | return NULL; |
534 | } |
535 | } |
536 | |
537 | /* |
538 | * Write to a file. Returns 0 on error, 1 on OK. |
539 | */ |
540 | int fxp_write(struct fxp_handle *handle, char *buffer, uint64 offset, int len) { |
541 | struct sftp_packet *pktin, *pktout; |
542 | int id; |
543 | |
544 | pktout = sftp_pkt_init(SSH_FXP_WRITE); |
545 | sftp_pkt_adduint32(pktout, 0xDCB); /* request id */ |
f9e162aa |
546 | sftp_pkt_addstring_start(pktout); |
547 | sftp_pkt_addstring_data(pktout, handle->hstring, handle->hlen); |
4c7f0d61 |
548 | sftp_pkt_adduint64(pktout, offset); |
549 | sftp_pkt_addstring_start(pktout); |
550 | sftp_pkt_addstring_data(pktout, buffer, len); |
551 | sftp_send(pktout); |
552 | pktin = sftp_recv(); |
553 | id = sftp_pkt_getuint32(pktin); |
4a8fc3c4 |
554 | if (id != 0xDCB) { |
555 | fxp_internal_error("request ID mismatch\n"); |
556 | return NULL; |
557 | } |
4c7f0d61 |
558 | fxp_got_status(pktin); |
559 | return fxp_errtype == SSH_FX_OK; |
560 | } |
561 | |
562 | /* |
563 | * Free up an fxp_names structure. |
564 | */ |
565 | void fxp_free_names(struct fxp_names *names) { |
566 | int i; |
567 | |
568 | for (i = 0; i < names->nnames; i++) { |
569 | sfree(names->names[i].filename); |
570 | sfree(names->names[i].longname); |
571 | } |
572 | sfree(names->names); |
573 | sfree(names); |
574 | } |