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
);
290 fxp_internal_error("could not connect");
293 if (pktin
->type
!= SSH_FXP_VERSION
) {
294 fxp_internal_error("did not receive FXP_VERSION");
297 remotever
= sftp_pkt_getuint32(pktin
);
298 if (remotever
> SFTP_PROTO_VERSION
) {
299 fxp_internal_error("remote protocol is more advanced than we support");
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_.
308 sftp_pkt_free(pktin
);
314 * Canonify a pathname.
316 char *fxp_realpath(char *path
) {
317 struct sftp_packet
*pktin
, *pktout
;
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
);
326 id
= sftp_pkt_getuint32(pktin
);
328 fxp_internal_error("request ID mismatch\n");
331 if (pktin
->type
== SSH_FXP_NAME
) {
336 count
= sftp_pkt_getuint32(pktin
);
338 fxp_internal_error("REALPATH returned name count != 1\n");
341 sftp_pkt_getstring(pktin
, &path
, &len
);
343 fxp_internal_error("REALPATH returned malformed FXP_NAME\n");
346 path
= mkstr(path
, len
);
347 sftp_pkt_free(pktin
);
350 fxp_got_status(pktin
);
358 struct fxp_handle
*fxp_open(char *path
, int type
) {
359 struct sftp_packet
*pktin
, *pktout
;
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 */
369 id
= sftp_pkt_getuint32(pktin
);
371 fxp_internal_error("request ID mismatch\n");
374 if (pktin
->type
== SSH_FXP_HANDLE
) {
377 struct fxp_handle
*handle
;
380 sftp_pkt_getstring(pktin
, &hstring
, &len
);
382 fxp_internal_error("OPEN returned malformed FXP_HANDLE\n");
385 handle
= smalloc(sizeof(struct fxp_handle
));
386 handle
->hstring
= mkstr(hstring
, len
);
388 sftp_pkt_free(pktin
);
391 fxp_got_status(pktin
);
399 struct fxp_handle
*fxp_opendir(char *path
) {
400 struct sftp_packet
*pktin
, *pktout
;
403 pktout
= sftp_pkt_init(SSH_FXP_OPENDIR
);
404 sftp_pkt_adduint32(pktout
, 0x456); /* request id */
405 sftp_pkt_addstring(pktout
, path
);
408 id
= sftp_pkt_getuint32(pktin
);
410 fxp_internal_error("request ID mismatch\n");
413 if (pktin
->type
== SSH_FXP_HANDLE
) {
416 struct fxp_handle
*handle
;
419 sftp_pkt_getstring(pktin
, &hstring
, &len
);
421 fxp_internal_error("OPENDIR returned malformed FXP_HANDLE\n");
424 handle
= smalloc(sizeof(struct fxp_handle
));
425 handle
->hstring
= mkstr(hstring
, len
);
427 sftp_pkt_free(pktin
);
430 fxp_got_status(pktin
);
438 void fxp_close(struct fxp_handle
*handle
) {
439 struct sftp_packet
*pktin
, *pktout
;
442 pktout
= sftp_pkt_init(SSH_FXP_CLOSE
);
443 sftp_pkt_adduint32(pktout
, 0x789); /* request id */
444 sftp_pkt_addstring_start(pktout
);
445 sftp_pkt_addstring_data(pktout
, handle
->hstring
, handle
->hlen
);
448 id
= sftp_pkt_getuint32(pktin
);
450 fxp_internal_error("request ID mismatch\n");
453 fxp_got_status(pktin
);
454 sfree(handle
->hstring
);
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.)
464 int fxp_read(struct fxp_handle
*handle
, char *buffer
, uint64 offset
, int len
) {
465 struct sftp_packet
*pktin
, *pktout
;
468 pktout
= sftp_pkt_init(SSH_FXP_READ
);
469 sftp_pkt_adduint32(pktout
, 0xBCD); /* request id */
470 sftp_pkt_addstring_start(pktout
);
471 sftp_pkt_addstring_data(pktout
, handle
->hstring
, handle
->hlen
);
472 sftp_pkt_adduint64(pktout
, offset
);
473 sftp_pkt_adduint32(pktout
, len
);
476 id
= sftp_pkt_getuint32(pktin
);
478 fxp_internal_error("request ID mismatch");
481 if (pktin
->type
== SSH_FXP_DATA
) {
485 sftp_pkt_getstring(pktin
, &str
, &rlen
);
487 if (rlen
> len
|| rlen
< 0) {
488 fxp_internal_error("READ returned more bytes than requested");
492 memcpy(buffer
, str
, rlen
);
496 fxp_got_status(pktin
);
502 * Read from a directory.
504 struct fxp_names
*fxp_readdir(struct fxp_handle
*handle
) {
505 struct sftp_packet
*pktin
, *pktout
;
508 pktout
= sftp_pkt_init(SSH_FXP_READDIR
);
509 sftp_pkt_adduint32(pktout
, 0xABC); /* request id */
510 sftp_pkt_addstring_start(pktout
);
511 sftp_pkt_addstring_data(pktout
, handle
->hstring
, handle
->hlen
);
514 id
= sftp_pkt_getuint32(pktin
);
516 fxp_internal_error("request ID mismatch\n");
519 if (pktin
->type
== SSH_FXP_NAME
) {
520 struct fxp_names
*ret
;
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
++) {
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
);
536 fxp_got_status(pktin
);
542 * Write to a file. Returns 0 on error, 1 on OK.
544 int fxp_write(struct fxp_handle
*handle
, char *buffer
, uint64 offset
, int len
) {
545 struct sftp_packet
*pktin
, *pktout
;
548 pktout
= sftp_pkt_init(SSH_FXP_WRITE
);
549 sftp_pkt_adduint32(pktout
, 0xDCB); /* request id */
550 sftp_pkt_addstring_start(pktout
);
551 sftp_pkt_addstring_data(pktout
, handle
->hstring
, handle
->hlen
);
552 sftp_pkt_adduint64(pktout
, offset
);
553 sftp_pkt_addstring_start(pktout
);
554 sftp_pkt_addstring_data(pktout
, buffer
, len
);
557 id
= sftp_pkt_getuint32(pktin
);
559 fxp_internal_error("request ID mismatch\n");
562 fxp_got_status(pktin
);
563 return fxp_errtype
== SSH_FX_OK
;
567 * Free up an fxp_names structure.
569 void fxp_free_names(struct fxp_names
*names
) {
572 for (i
= 0; i
< names
->nnames
; i
++) {
573 sfree(names
->names
[i
].filename
);
574 sfree(names
->names
[i
].longname
);