7 files changed, 151 insertions, 20 deletions

diff --git a/ChangeLog b/ChangeLog
index a8aeacc56..4e60f137f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -11,6 +11,13 @@
      [auth-rsa.c]
      move check for revoked keys to run earlier (in auth_rsa_key_allowed)
      bz#1829; patch from ldv AT altlinux.org; ok markus@
+   - djm@cvs.openbsd.org 2010/12/04 00:18:01
+     [sftp-server.c sftp.1 sftp-client.h sftp.c PROTOCOL sftp-client.c]
+     add a protocol extension to support a hard link operation. It is
+     available through the "ln" command in the client. The old "ln"
+     behaviour of creating a symlink is available using its "-s" option
+     or through the preexisting "symlink" command; based on a patch from
+     miklos AT szeredi.hu in bz#1555; ok markus@
 
 20101204
  - (djm) [openbsd-compat/bindresvport.c] Use arc4random_uniform(range)
diff --git a/PROTOCOL b/PROTOCOL
index 5d2a7118a..c28196011 100644
--- a/PROTOCOL
+++ b/PROTOCOL
@@ -275,4 +275,20 @@ The values of the f_flag bitmask are as follows:
 Both the "statvfs@openssh.com" and "fstatvfs@openssh.com" extensions are
 advertised in the SSH_FXP_VERSION hello with version "2".
 
-$OpenBSD: PROTOCOL,v 1.16 2010/08/31 11:54:45 djm Exp $
+10. sftp: Extension request "hardlink@openssh.com"
+
+This request is for creating a hard link to a regular file. This
+request is implemented as a SSH_FXP_EXTENDED request with the
+following format:
+
+        uint32          id
+        string          "hardlink@openssh.com"
+        string          oldpath
+        string          newpath
+
+On receiving this request the server will perform the operation
+link(oldpath, newpath) and will respond with a SSH_FXP_STATUS message.
+This extension is advertised in the SSH_FXP_VERSION hello with version
+"1".
+
+$OpenBSD: PROTOCOL,v 1.17 2010/12/04 00:18:01 djm Exp $
diff --git a/sftp-client.c b/sftp-client.c
index 4e009ef25..caa384b4e 100644
--- a/sftp-client.c
+++ b/sftp-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.c,v 1.93 2010/09/22 22:58:51 djm Exp $ */
+/* $OpenBSD: sftp-client.c,v 1.94 2010/12/04 00:18:01 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -75,6 +75,7 @@ struct sftp_conn {
 #define SFTP_EXT_POSIX_RENAME   0x00000001
 #define SFTP_EXT_STATVFS        0x00000002
 #define SFTP_EXT_FSTATVFS       0x00000004
+#define SFTP_EXT_HARDLINK       0x00000008
         u_int exts;
         u_int64_t limit_kbps;
         struct bwlimit bwlimit_in, bwlimit_out;
@@ -378,10 +379,14 @@ do_init(int fd_in, int fd_out, u_int transfer_buflen, u_int num_requests,
                     strcmp(value, "2") == 0) {
                         ret->exts |= SFTP_EXT_STATVFS;
                         known = 1;
-                } if (strcmp(name, "fstatvfs@openssh.com") == 0 &&
+                } else if (strcmp(name, "fstatvfs@openssh.com") == 0 &&
                     strcmp(value, "2") == 0) {
                         ret->exts |= SFTP_EXT_FSTATVFS;
                         known = 1;
+                } else if (strcmp(name, "hardlink@openssh.com") == 0 &&
+                    strcmp(value, "1") == 0) {
+                        ret->exts |= SFTP_EXT_HARDLINK;
+                        known = 1;
                 }
                 if (known) {
                         debug2("Server supports extension \"%s\" revision %s",
@@ -795,6 +800,39 @@ do_rename(struct sftp_conn *conn, char *oldpath, char *newpath)
 }
 
 int
+do_hardlink(struct sftp_conn *conn, char *oldpath, char *newpath)
+{
+        Buffer msg;
+        u_int status, id;
+
+        buffer_init(&msg);
+
+        /* Send link request */
+        id = conn->msg_id++;
+        if ((conn->exts & SFTP_EXT_HARDLINK) == 0) {
+                error("Server does not support hardlink@openssh.com extension");
+                return -1;
+        }
+
+        buffer_put_char(&msg, SSH2_FXP_EXTENDED);
+        buffer_put_int(&msg, id);
+        buffer_put_cstring(&msg, "hardlink@openssh.com");
+        buffer_put_cstring(&msg, oldpath);
+        buffer_put_cstring(&msg, newpath);
+        send_msg(conn, &msg);
+        debug3("Sent message hardlink@openssh.com \"%s\" -> \"%s\"",
+               oldpath, newpath);
+        buffer_free(&msg);
+
+        status = get_status(conn, id);
+        if (status != SSH2_FX_OK)
+                error("Couldn't link file \"%s\" to \"%s\": %s", oldpath,
+                    newpath, fx2txt(status));
+
+        return(status);
+}
+
+int
 do_symlink(struct sftp_conn *conn, char *oldpath, char *newpath)
 {
         Buffer msg;
diff --git a/sftp-client.h b/sftp-client.h
index 145fc38ee..aef54ef49 100644
--- a/sftp-client.h
+++ b/sftp-client.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.h,v 1.19 2010/09/22 22:58:51 djm Exp $ */
+/* $OpenBSD: sftp-client.h,v 1.20 2010/12/04 00:18:01 djm Exp $ */
 
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
@@ -94,6 +94,9 @@ int do_statvfs(struct sftp_conn *, const char *, struct sftp_statvfs *, int);
 /* Rename 'oldpath' to 'newpath' */
 int do_rename(struct sftp_conn *, char *, char *);
 
+/* Link 'oldpath' to 'newpath' */
+int do_hardlink(struct sftp_conn *, char *, char *);
+
 /* Rename 'oldpath' to 'newpath' */
 int do_symlink(struct sftp_conn *, char *, char *);
 
diff --git a/sftp-server.c b/sftp-server.c
index 47edcd0aa..b268d0883 100644
--- a/sftp-server.c
+++ b/sftp-server.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-server.c,v 1.92 2010/11/04 02:45:34 djm Exp $ */
+/* $OpenBSD: sftp-server.c,v 1.93 2010/12/04 00:18:01 djm Exp $ */
 /*
  * Copyright (c) 2000-2004 Markus Friedl.  All rights reserved.
  *
@@ -535,6 +535,9 @@ process_init(void)
         /* fstatvfs extension */
         buffer_put_cstring(&msg, "fstatvfs@openssh.com");
         buffer_put_cstring(&msg, "2"); /* version */
+        /* hardlink extension */
+        buffer_put_cstring(&msg, "hardlink@openssh.com");
+        buffer_put_cstring(&msg, "1"); /* version */
         send_msg(&msg);
         buffer_free(&msg);
 }
@@ -1223,6 +1226,27 @@ process_extended_fstatvfs(u_int32_t id)
 }
 
 static void
+process_extended_hardlink(u_int32_t id)
+{
+        char *oldpath, *newpath;
+        int ret, status;
+
+        oldpath = get_string(NULL);
+        newpath = get_string(NULL);
+        debug3("request %u: hardlink", id);
+        logit("hardlink old \"%s\" new \"%s\"", oldpath, newpath);
+        if (readonly)
+                status = SSH2_FX_PERMISSION_DENIED;
+        else {
+                ret = link(oldpath, newpath);
+                status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
+        }
+        send_status(id, status);
+        xfree(oldpath);
+        xfree(newpath);
+}
+
+static void
 process_extended(void)
 {
         u_int32_t id;
@@ -1236,6 +1260,8 @@ process_extended(void)
                 process_extended_statvfs(id);
         else if (strcmp(request, "fstatvfs@openssh.com") == 0)
                 process_extended_fstatvfs(id);
+        else if (strcmp(request, "hardlink@openssh.com") == 0)
+                process_extended_hardlink(id);
         else
                 send_status(id, SSH2_FX_OP_UNSUPPORTED);        /* MUST */
         xfree(request);
diff --git a/sftp.1 b/sftp.1
index 3bb0c0646..89b5d3544 100644
--- a/sftp.1
+++ b/sftp.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: sftp.1,v 1.87 2010/11/18 15:01:00 jmc Exp $
+.\" $OpenBSD: sftp.1,v 1.88 2010/12/04 00:18:01 djm Exp $
 .\"
 .\" Copyright (c) 2001 Damien Miller.  All rights reserved.
 .\"
@@ -22,7 +22,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: November 18 2010 $
+.Dd $Mdocdate: December 4 2010 $
 .Dt SFTP 1
 .Os
 .Sh NAME
@@ -128,7 +128,7 @@ commands fail:
 .Ic get , put , rename , ln ,
 .Ic rm , mkdir , chdir , ls ,
 .Ic lchdir , chmod , chown ,
-.Ic chgrp , lpwd , df ,
+.Ic chgrp , lpwd , df , symlink ,
 and
 .Ic lmkdir .
 Termination on error can be suppressed on a command by command basis by
@@ -392,11 +392,19 @@ characters and may match multiple files.
 .It Ic lmkdir Ar path
 Create local directory specified by
 .Ar path .
-.It Ic ln Ar oldpath Ar newpath
-Create a symbolic link from
+.It Xo Ic ln
+.Op Fl s
+.Ar oldpath
+.Ar newpath
+.Xc
+Create a link from
 .Ar oldpath
 to
 .Ar newpath .
+If the
+.Fl s
+flag is specified the created link is a symbolic link, otherwise it is
+a hard link.
 .It Ic lpwd
 Print local working directory.
 .It Xo Ic ls
diff --git a/sftp.c b/sftp.c
index d605505ea..ab667f5a5 100644
--- a/sftp.c
+++ b/sftp.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp.c,v 1.131 2010/10/23 22:06:12 sthen Exp $ */
+/* $OpenBSD: sftp.c,v 1.132 2010/12/04 00:18:01 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -132,6 +132,7 @@ extern char *__progname;
 #define I_GET           5
 #define I_HELP          6
 #define I_LCHDIR        7
+#define I_LINK          25
 #define I_LLS           8
 #define I_LMKDIR        9
 #define I_LPWD          10
@@ -176,7 +177,7 @@ static const struct CMD cmds[] = {
         { "lchdir",     I_LCHDIR,       LOCAL   },
         { "lls",        I_LLS,          LOCAL   },
         { "lmkdir",     I_LMKDIR,       LOCAL   },
-        { "ln",         I_SYMLINK,      REMOTE  },
+        { "ln",         I_LINK,         REMOTE  },
         { "lpwd",       I_LPWD,         LOCAL   },
         { "ls",         I_LS,           REMOTE  },
         { "lumask",     I_LUMASK,       NOARGS  },
@@ -240,7 +241,7 @@ help(void)
             "lcd path                           Change local directory to 'path'\n"
             "lls [ls-options [path]]            Display local directory listing\n"
             "lmkdir path                        Create local directory\n"
-            "ln oldpath newpath                 Symlink remote file\n"
+            "ln [-s] oldpath newpath            Link remote file (-s for symlink)\n"
             "lpwd                               Print local working directory\n"
             "ls [-1afhlnrSt] [path]             Display remote directory listing\n"
             "lumask umask                       Set local umask to 'umask'\n"
@@ -377,6 +378,30 @@ parse_getput_flags(const char *cmd, char **argv, int argc, int *pflag,
 }
 
 static int
+parse_link_flags(const char *cmd, char **argv, int argc, int *sflag)
+{
+        extern int opterr, optind, optopt, optreset;
+        int ch;
+
+        optind = optreset = 1;
+        opterr = 0;
+
+        *sflag = 0;
+        while ((ch = getopt(argc, argv, "s")) != -1) {
+                switch (ch) {
+                case 's':
+                        *sflag = 1;
+                        break;
+                default:
+                        error("%s: Invalid flag -%c", cmd, optopt);
+                        return -1;
+                }
+        }
+
+        return optind;
+}
+
+static int
 parse_ls_flags(char **argv, int argc, int *lflag)
 {
         extern int opterr, optind, optopt, optreset;
@@ -1088,7 +1113,7 @@ makeargv(const char *arg, int *argcp, int sloppy, char *lastquote,
 
 static int
 parse_args(const char **cpp, int *pflag, int *rflag, int *lflag, int *iflag,
-    int *hflag, unsigned long *n_arg, char **path1, char **path2)
+    int *hflag, int *sflag, unsigned long *n_arg, char **path1, char **path2)
 {
         const char *cmd, *cp = *cpp;
         char *cp2, **argv;
@@ -1138,7 +1163,8 @@ parse_args(const char **cpp, int *pflag, int *rflag, int *lflag, int *iflag,
         switch (cmdnum) {
         case I_GET:
         case I_PUT:
-                if ((optidx = parse_getput_flags(cmd, argv, argc, pflag, rflag)) == -1)
+                if ((optidx = parse_getput_flags(cmd, argv, argc,
+                    pflag, rflag)) == -1)
                         return -1;
                 /* Get first pathname (mandatory) */
                 if (argc - optidx < 1) {
@@ -1154,8 +1180,11 @@ parse_args(const char **cpp, int *pflag, int *rflag, int *lflag, int *iflag,
                         undo_glob_escape(*path2);
                 }
                 break;
-        case I_RENAME:
+        case I_LINK:
+                if ((optidx = parse_link_flags(cmd, argv, argc, sflag)) == -1)
+                        return -1;
         case I_SYMLINK:
+        case I_RENAME:
                 if (argc - optidx < 2) {
                         error("You must specify two paths after a %s "
                             "command.", cmd);
@@ -1258,7 +1287,8 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
     int err_abort)
 {
         char *path1, *path2, *tmp;
-        int pflag = 0, rflag = 0, lflag = 0, iflag = 0, hflag = 0, cmdnum, i;
+        int pflag = 0, rflag = 0, lflag = 0, iflag = 0, hflag = 0, sflag = 0;
+        int cmdnum, i;
         unsigned long n_arg = 0;
         Attrib a, *aa;
         char path_buf[MAXPATHLEN];
@@ -1266,8 +1296,8 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
         glob_t g;
 
         path1 = path2 = NULL;
-        cmdnum = parse_args(&cmd, &pflag, &rflag, &lflag, &iflag, &hflag, &n_arg,
-            &path1, &path2);
+        cmdnum = parse_args(&cmd, &pflag, &rflag, &lflag, &iflag, &hflag,
+            &sflag, &n_arg, &path1, &path2);
 
         if (iflag != 0)
                 err_abort = 0;
@@ -1295,8 +1325,11 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
                 err = do_rename(conn, path1, path2);
                 break;
         case I_SYMLINK:
+                sflag = 1;
+        case I_LINK:
+                path1 = make_absolute(path1, *pwd);
                 path2 = make_absolute(path2, *pwd);
-                err = do_symlink(conn, path1, path2);
+                err = (sflag ? do_symlink : do_hardlink)(conn, path1, path2);
                 break;
         case I_RM:
                 path1 = make_absolute(path1, *pwd);