+/*
+ * sftp.c: SFTP generic client code.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+
+#include "int64.h"
+#include "sftp.h"
+
+#define smalloc malloc
+#define srealloc realloc
+#define sfree free
+
+#define GET_32BIT(cp) \
+ (((unsigned long)(unsigned char)(cp)[0] << 24) | \
+ ((unsigned long)(unsigned char)(cp)[1] << 16) | \
+ ((unsigned long)(unsigned char)(cp)[2] << 8) | \
+ ((unsigned long)(unsigned char)(cp)[3]))
+
+#define PUT_32BIT(cp, value) { \
+ (cp)[0] = (unsigned char)((value) >> 24); \
+ (cp)[1] = (unsigned char)((value) >> 16); \
+ (cp)[2] = (unsigned char)((value) >> 8); \
+ (cp)[3] = (unsigned char)(value); }
+
+struct sftp_packet {
+ char *data;
+ int length, maxlen;
+ int savedpos;
+ int type;
+};
+
+/* ----------------------------------------------------------------------
+ * SFTP packet construction functions.
+ */
+static void sftp_pkt_ensure(struct sftp_packet *pkt, int length) {
+ if (pkt->maxlen < length) {
+ pkt->maxlen = length + 256;
+ pkt->data = srealloc(pkt->data, pkt->maxlen);
+ }
+}
+static void sftp_pkt_adddata(struct sftp_packet *pkt, void *data, int len) {
+ pkt->length += len;
+ sftp_pkt_ensure(pkt, pkt->length);
+ memcpy(pkt->data+pkt->length-len, data, len);
+}
+static void sftp_pkt_addbyte(struct sftp_packet *pkt, unsigned char byte) {
+ sftp_pkt_adddata(pkt, &byte, 1);
+}
+static struct sftp_packet *sftp_pkt_init(int pkt_type) {
+ struct sftp_packet *pkt;
+ pkt = smalloc(sizeof(struct sftp_packet));
+ pkt->data = NULL;
+ pkt->savedpos = -1;
+ pkt->length = 0;
+ pkt->maxlen = 0;
+ sftp_pkt_addbyte(pkt, (unsigned char)pkt_type);
+ return pkt;
+}
+static void sftp_pkt_addbool(struct sftp_packet *pkt, unsigned char value) {
+ sftp_pkt_adddata(pkt, &value, 1);
+}
+static void sftp_pkt_adduint32(struct sftp_packet *pkt, unsigned long value) {
+ unsigned char x[4];
+ PUT_32BIT(x, value);
+ sftp_pkt_adddata(pkt, x, 4);
+}
+static void sftp_pkt_adduint64(struct sftp_packet *pkt, uint64 value) {
+ unsigned char x[8];
+ PUT_32BIT(x, value.hi);
+ PUT_32BIT(x+4, value.lo);
+ sftp_pkt_adddata(pkt, x, 8);
+}
+static void sftp_pkt_addstring_start(struct sftp_packet *pkt) {
+ sftp_pkt_adduint32(pkt, 0);
+ pkt->savedpos = pkt->length;
+}
+static void sftp_pkt_addstring_str(struct sftp_packet *pkt, char *data) {
+ sftp_pkt_adddata(pkt, data, strlen(data));
+ PUT_32BIT(pkt->data + pkt->savedpos - 4,
+ pkt->length - pkt->savedpos);
+}
+static void sftp_pkt_addstring_data(struct sftp_packet *pkt,
+ char *data, int len) {
+ sftp_pkt_adddata(pkt, data, len);
+ PUT_32BIT(pkt->data + pkt->savedpos - 4,
+ pkt->length - pkt->savedpos);
+}
+static void sftp_pkt_addstring(struct sftp_packet *pkt, char *data) {
+ sftp_pkt_addstring_start(pkt);
+ sftp_pkt_addstring_str(pkt, data);
+}
+
+/* ----------------------------------------------------------------------
+ * SFTP packet decode functions.
+ */
+
+static unsigned char sftp_pkt_getbyte(struct sftp_packet *pkt) {
+ unsigned long value;
+ if (pkt->length - pkt->savedpos < 1)
+ return 0; /* arrgh, no way to decline (FIXME?) */
+ value = (unsigned char) pkt->data[pkt->savedpos];
+ pkt->savedpos++;
+ return value;
+}
+static unsigned long sftp_pkt_getuint32(struct sftp_packet *pkt) {
+ unsigned long value;
+ if (pkt->length - pkt->savedpos < 4)
+ return 0; /* arrgh, no way to decline (FIXME?) */
+ value = GET_32BIT(pkt->data+pkt->savedpos);
+ pkt->savedpos += 4;
+ return value;
+}
+static void sftp_pkt_getstring(struct sftp_packet *pkt,
+ char **p, int *length) {
+ *p = NULL;
+ if (pkt->length - pkt->savedpos < 4)
+ return;
+ *length = GET_32BIT(pkt->data+pkt->savedpos);
+ pkt->savedpos += 4;
+ if (pkt->length - pkt->savedpos < *length)
+ return;
+ *p = pkt->data+pkt->savedpos;
+ pkt->savedpos += *length;
+}
+static struct fxp_attrs sftp_pkt_getattrs(struct sftp_packet *pkt) {
+ struct fxp_attrs ret;
+ ret.flags = sftp_pkt_getuint32(pkt);
+ if (ret.flags & SSH_FILEXFER_ATTR_SIZE) {
+ unsigned long hi, lo;
+ hi = sftp_pkt_getuint32(pkt);
+ lo = sftp_pkt_getuint32(pkt);
+ ret.size = uint64_make(hi, lo);
+ }
+ if (ret.flags & SSH_FILEXFER_ATTR_UIDGID) {
+ ret.uid = sftp_pkt_getuint32(pkt);
+ ret.gid = sftp_pkt_getuint32(pkt);
+ }
+ if (ret.flags & SSH_FILEXFER_ATTR_PERMISSIONS) {
+ ret.permissions = sftp_pkt_getuint32(pkt);
+ }
+ if (ret.flags & SSH_FILEXFER_ATTR_ACMODTIME) {
+ ret.atime = sftp_pkt_getuint32(pkt);
+ ret.mtime = sftp_pkt_getuint32(pkt);
+ }
+ if (ret.flags & SSH_FILEXFER_ATTR_EXTENDED) {
+ int count;
+ count = sftp_pkt_getuint32(pkt);
+ while (count--) {
+ char *str;
+ int len;
+ /*
+ * We should try to analyse these, if we ever find one
+ * we recognise.
+ */
+ sftp_pkt_getstring(pkt, &str, &len);
+ sftp_pkt_getstring(pkt, &str, &len);
+ }
+ }
+ return ret;
+}
+static void sftp_pkt_free(struct sftp_packet *pkt) {
+ if (pkt->data) sfree(pkt->data);
+ sfree(pkt);
+}
+
+/* ----------------------------------------------------------------------
+ * Send and receive packet functions. FIXME: change for PuTTY.
+ */
+int tossh, fromssh;
+int io_init(void) {
+ int to[2], from[2];
+ int pid;
+
+ assert(pipe(to) == 0);
+ assert(pipe(from) == 0);
+ pid = fork();
+ assert(pid >= 0);
+ if (pid == 0) {
+ /* We are child. Dup one end of each pipe to our std[io],
+ * close other end, exec. */
+ close(0); dup2(to[0], 0); close(to[1]);
+ close(1); dup2(from[1], 1); close(from[0]);
+ execl("/home/simon/src/openssh/openssh_cvs/prefix/bin/ssh", "ssh", "-2", "simon@localhost", "-s", "sftp", NULL);
+ assert(0); /* bomb out if not */
+ } else {
+ /* We are parent. Close wrong end of each pipe, assign to glob vars. */
+ close(to[0]); tossh = to[1];
+ close(from[1]); fromssh = from[0];
+ }
+}
+int io_finish(void) {
+ int pid, status;
+ close(tossh);
+ close(fromssh);
+ pid = wait(&status);
+}
+int sftp_send(struct sftp_packet *pkt) {
+ char x[4];
+ PUT_32BIT(x, pkt->length);
+ assert(4 == write(tossh, x, 4));
+ assert(pkt->length = write(tossh, pkt->data, pkt->length));
+ sftp_pkt_free(pkt);
+}
+struct sftp_packet *sftp_recv(void) {
+ struct sftp_packet *pkt;
+ char x[4];
+ int p, ret;
+
+ for (p = 0; p < 4 ;) {
+ ret = read(fromssh, x+p, 4-p);
+ assert(ret >= 0);
+ if (ret == 0)
+ return NULL;
+ p += ret;
+ }
+
+ pkt = smalloc(sizeof(struct sftp_packet));
+ pkt->savedpos = 0;
+ pkt->length = pkt->maxlen = GET_32BIT(x);
+ pkt->data = smalloc(pkt->length);
+
+ for (p = 0; p < pkt->length ;) {
+ ret = read(fromssh, pkt->data+p, pkt->length-p);
+ assert(ret >= 0);
+ if (ret == 0) {
+ sftp_pkt_free(pkt);
+ return NULL;
+ }
+ p += ret;
+ }
+
+ pkt->type = sftp_pkt_getbyte(pkt);
+
+ return pkt;
+}
+
+/* ----------------------------------------------------------------------
+ * String handling routines.
+ */
+
+static char *mkstr(char *s, int len) {
+ char *p = smalloc(len+1);
+ memcpy(p, s, len);
+ p[len] = '\0';
+ return p;
+}
+
+/* ----------------------------------------------------------------------
+ * SFTP primitives.
+ */
+
+static const char *fxp_error_message;
+static int fxp_errtype;
+
+/*
+ * Deal with (and free) an FXP_STATUS packet. Return 1 if
+ * SSH_FX_OK, 0 if SSH_FX_EOF, and -1 for anything else (error).
+ * Also place the status into fxp_errtype.
+ */
+static int fxp_got_status(struct sftp_packet *pktin) {
+ static const char *const messages[] = {
+ /* SSH_FX_OK. The only time we will display a _message_ for this
+ * is if we were expecting something other than FXP_STATUS on
+ * success, so this is actually an error message! */
+ "unexpected OK response",
+ "end of file",
+ "no such file or directory",
+ "permission denied",
+ "failure",
+ "bad message",
+ "no connection",
+ "connection lost",
+ "operation unsupported",
+ };
+
+ if (pktin->type != SSH_FXP_STATUS) {
+ fxp_error_message = "expected FXP_STATUS packet";
+ fxp_errtype = -1;
+ } else {
+ fxp_errtype = sftp_pkt_getuint32(pktin);
+ if (fxp_errtype < 0 ||
+ fxp_errtype >= sizeof(messages)/sizeof(*messages))
+ fxp_error_message = "unknown error code";
+ else
+ fxp_error_message = messages[fxp_errtype];
+ }
+
+ if (fxp_errtype == SSH_FX_OK)
+ return 1;
+ else if (fxp_errtype == SSH_FX_EOF)
+ return 0;
+ else
+ return -1;
+}
+
+static int fxp_internal_error(char *msg) {
+ fxp_error_message = msg;
+ fxp_errtype = -1;
+}
+
+const char *fxp_error(void) {
+ return fxp_error_message;
+}
+
+int fxp_error_type(void) {
+ return fxp_errtype;
+}
+
+/*
+ * Perform exchange of init/version packets. Return 0 on failure.
+ */
+int fxp_init(void) {
+ struct sftp_packet *pktout, *pktin;
+ int remotever;
+
+ pktout = sftp_pkt_init(SSH_FXP_INIT);
+ sftp_pkt_adduint32(pktout, SFTP_PROTO_VERSION);
+ sftp_send(pktout);
+
+ pktin = sftp_recv();
+ if (pktin->type != SSH_FXP_VERSION) {
+ fxp_internal_error("did not receive FXP_VERSION");
+ return 0;
+ }
+ remotever = sftp_pkt_getuint32(pktin);
+ if (remotever > SFTP_PROTO_VERSION) {
+ fxp_internal_error("remote protocol is more advanced than we support");
+ return 0;
+ }
+ /*
+ * In principle, this packet might also contain extension-
+ * string pairs. We should work through them and look for any
+ * we recognise. In practice we don't currently do so because
+ * we know we don't recognise _any_.
+ */
+ sftp_pkt_free(pktin);
+
+ return 1;
+}
+
+/*
+ * Canonify a pathname. Concatenate the two given path elements
+ * with a separating slash, unless the second is NULL.
+ */
+char *fxp_realpath(char *path, char *path2) {
+ struct sftp_packet *pktin, *pktout;
+ int id;
+
+ pktout = sftp_pkt_init(SSH_FXP_REALPATH);
+ sftp_pkt_adduint32(pktout, 0x123); /* request id */
+ sftp_pkt_addstring_start(pktout);
+ sftp_pkt_addstring_str(pktout, path);
+ if (path2) {
+ sftp_pkt_addstring_str(pktout, "/");
+ sftp_pkt_addstring_str(pktout, path2);
+ }
+ sftp_send(pktout);
+ pktin = sftp_recv();
+ id = sftp_pkt_getuint32(pktin);
+ if (id != 0x123) {
+ fxp_internal_error("request ID mismatch\n");
+ return NULL;
+ }
+ if (pktin->type == SSH_FXP_NAME) {
+ int count;
+ char *path;
+ int len;
+
+ count = sftp_pkt_getuint32(pktin);
+ if (count != 1) {
+ fxp_internal_error("REALPATH returned name count != 1\n");
+ return NULL;
+ }
+ sftp_pkt_getstring(pktin, &path, &len);
+ if (!path) {
+ fxp_internal_error("REALPATH returned malformed FXP_NAME\n");
+ return NULL;
+ }
+ path = mkstr(path, len);
+ sftp_pkt_free(pktin);
+ return path;
+ } else {
+ fxp_got_status(pktin);
+ return NULL;
+ }
+}
+
+/*
+ * Open a file.
+ */
+struct fxp_handle *fxp_open(char *path, int type) {
+ struct sftp_packet *pktin, *pktout;
+ int id;
+
+ pktout = sftp_pkt_init(SSH_FXP_OPEN);
+ sftp_pkt_adduint32(pktout, 0x567); /* request id */
+ sftp_pkt_addstring(pktout, path);
+ sftp_pkt_adduint32(pktout, type);
+ sftp_pkt_adduint32(pktout, 0); /* (FIXME) empty ATTRS structure */
+ sftp_send(pktout);
+ pktin = sftp_recv();
+ id = sftp_pkt_getuint32(pktin);
+ if (id != 0x567) {
+ fxp_internal_error("request ID mismatch\n");
+ return NULL;
+ }
+ if (pktin->type == SSH_FXP_HANDLE) {
+ int count;
+ char *hstring;
+ struct fxp_handle *handle;
+ int len;
+
+ sftp_pkt_getstring(pktin, &hstring, &len);
+ if (!hstring) {
+ fxp_internal_error("OPEN returned malformed FXP_HANDLE\n");
+ return NULL;
+ }
+ handle = smalloc(sizeof(struct fxp_handle));
+ handle->hstring = mkstr(hstring, len);
+ sftp_pkt_free(pktin);
+ return handle;
+ } else {
+ fxp_got_status(pktin);
+ return NULL;
+ }
+}
+
+/*
+ * Open a directory.
+ */
+struct fxp_handle *fxp_opendir(char *path) {
+ struct sftp_packet *pktin, *pktout;
+ int id;
+
+ pktout = sftp_pkt_init(SSH_FXP_OPENDIR);
+ sftp_pkt_adduint32(pktout, 0x456); /* request id */
+ sftp_pkt_addstring(pktout, path);
+ sftp_send(pktout);
+ pktin = sftp_recv();
+ id = sftp_pkt_getuint32(pktin);
+ if (id != 0x456) {
+ fxp_internal_error("request ID mismatch\n");
+ return NULL;
+ }
+ if (pktin->type == SSH_FXP_HANDLE) {
+ int count;
+ char *hstring;
+ struct fxp_handle *handle;
+ int len;
+
+ sftp_pkt_getstring(pktin, &hstring, &len);
+ if (!hstring) {
+ fxp_internal_error("OPENDIR returned malformed FXP_HANDLE\n");
+ return NULL;
+ }
+ handle = smalloc(sizeof(struct fxp_handle));
+ handle->hstring = mkstr(hstring, len);
+ sftp_pkt_free(pktin);
+ return handle;
+ } else {
+ fxp_got_status(pktin);
+ return NULL;
+ }
+}
+
+/*
+ * Close a file/dir.
+ */
+void fxp_close(struct fxp_handle *handle) {
+ struct sftp_packet *pktin, *pktout;
+ int id;
+
+ pktout = sftp_pkt_init(SSH_FXP_CLOSE);
+ sftp_pkt_adduint32(pktout, 0x789); /* request id */
+ sftp_pkt_addstring(pktout, handle->hstring);
+ sftp_send(pktout);
+ pktin = sftp_recv();
+ id = sftp_pkt_getuint32(pktin);
+ if (id != 0x789) {
+ fxp_internal_error("request ID mismatch\n");
+ return;
+ }
+ fxp_got_status(pktin);
+ sfree(handle->hstring);
+ sfree(handle);
+}
+
+/*
+ * Read from a file. Returns the number of bytes read, or -1 on an
+ * error, or possibly 0 if EOF. (I'm not entirely sure whether it
+ * will return 0 on EOF, or return -1 and store SSH_FX_EOF in the
+ * error indicator. It might even depend on the SFTP server.)
+ */
+int fxp_read(struct fxp_handle *handle, char *buffer, uint64 offset, int len) {
+ struct sftp_packet *pktin, *pktout;
+ int id;
+
+ pktout = sftp_pkt_init(SSH_FXP_READ);
+ sftp_pkt_adduint32(pktout, 0xBCD); /* request id */
+ sftp_pkt_addstring(pktout, handle->hstring);
+ sftp_pkt_adduint64(pktout, offset);
+ sftp_pkt_adduint32(pktout, len);
+ sftp_send(pktout);
+ pktin = sftp_recv();
+ id = sftp_pkt_getuint32(pktin);
+ if (id != 0xBCD) {
+ fxp_internal_error("request ID mismatch");
+ return;
+ }
+ if (pktin->type == SSH_FXP_DATA) {
+ char *str;
+ int rlen;
+
+ sftp_pkt_getstring(pktin, &str, &rlen);
+
+ if (rlen > len || rlen < 0) {
+ fxp_internal_error("READ returned more bytes than requested");
+ return -1;
+ }
+
+ memcpy(buffer, str, rlen);
+ sfree(pktin);
+ return rlen;
+ } else {
+ fxp_got_status(pktin);
+ return -1;
+ }
+}
+
+/*
+ * Read from a directory.
+ */
+struct fxp_names *fxp_readdir(struct fxp_handle *handle) {
+ struct sftp_packet *pktin, *pktout;
+ int id;
+
+ pktout = sftp_pkt_init(SSH_FXP_READDIR);
+ sftp_pkt_adduint32(pktout, 0xABC); /* request id */
+ sftp_pkt_addstring(pktout, handle->hstring);
+ sftp_send(pktout);
+ pktin = sftp_recv();
+ id = sftp_pkt_getuint32(pktin);
+ if (id != 0xABC) {
+ fxp_internal_error("request ID mismatch\n");
+ return;
+ }
+ if (pktin->type == SSH_FXP_NAME) {
+ struct fxp_names *ret;
+ int i;
+ ret = smalloc(sizeof(struct fxp_names));
+ ret->nnames = sftp_pkt_getuint32(pktin);
+ ret->names = smalloc(ret->nnames * sizeof(struct fxp_name));
+ for (i = 0; i < ret->nnames; i++) {
+ char *str;
+ int len;
+ sftp_pkt_getstring(pktin, &str, &len);
+ ret->names[i].filename = mkstr(str, len);
+ sftp_pkt_getstring(pktin, &str, &len);
+ ret->names[i].longname = mkstr(str, len);
+ ret->names[i].attrs = sftp_pkt_getattrs(pktin);
+ }
+ return ret;
+ } else {
+ fxp_got_status(pktin);
+ return NULL;
+ }
+}
+
+/*
+ * Write to a file. Returns 0 on error, 1 on OK.
+ */
+int fxp_write(struct fxp_handle *handle, char *buffer, uint64 offset, int len) {
+ struct sftp_packet *pktin, *pktout;
+ int id;
+
+ pktout = sftp_pkt_init(SSH_FXP_WRITE);
+ sftp_pkt_adduint32(pktout, 0xDCB); /* request id */
+ sftp_pkt_addstring(pktout, handle->hstring);
+ sftp_pkt_adduint64(pktout, offset);
+ sftp_pkt_addstring_start(pktout);
+ sftp_pkt_addstring_data(pktout, buffer, len);
+ sftp_send(pktout);
+ pktin = sftp_recv();
+ id = sftp_pkt_getuint32(pktin);
+ fxp_got_status(pktin);
+ return fxp_errtype == SSH_FX_OK;
+}
+
+/*
+ * Free up an fxp_names structure.
+ */
+void fxp_free_names(struct fxp_names *names) {
+ int i;
+
+ for (i = 0; i < names->nnames; i++) {
+ sfree(names->names[i].filename);
+ sfree(names->names[i].longname);
+ }
+ sfree(names->names);
+ sfree(names);
+}