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
);