Imported Upstream version 2.14.1
[platform/upstream/git.git] / connect.c
index 912cdde..49b28b8 100644 (file)
--- a/connect.c
+++ b/connect.c
@@ -1,36 +1,38 @@
 #include "git-compat-util.h"
 #include "cache.h"
+#include "config.h"
 #include "pkt-line.h"
 #include "quote.h"
 #include "refs.h"
 #include "run-command.h"
 #include "remote.h"
+#include "connect.h"
 #include "url.h"
+#include "string-list.h"
+#include "sha1-array.h"
+#include "transport.h"
 
 static char *server_capabilities;
+static const char *parse_feature_value(const char *, const char *, int *);
 
-static int check_ref(const char *name, int len, unsigned int flags)
+static int check_ref(const char *name, unsigned int flags)
 {
        if (!flags)
                return 1;
 
-       if (len < 5 || memcmp(name, "refs/", 5))
+       if (!skip_prefix(name, "refs/", &name))
                return 0;
 
-       /* Skip the "refs/" part */
-       name += 5;
-       len -= 5;
-
        /* REF_NORMAL means that we don't want the magic fake tag refs */
        if ((flags & REF_NORMAL) && check_refname_format(name, 0))
                return 0;
 
        /* REF_HEADS means that we want regular branch heads */
-       if ((flags & REF_HEADS) && !memcmp(name, "heads/", 6))
+       if ((flags & REF_HEADS) && starts_with(name, "heads/"))
                return 1;
 
        /* REF_TAGS means that we want tags */
-       if ((flags & REF_TAGS) && !memcmp(name, "tags/", 5))
+       if ((flags & REF_TAGS) && starts_with(name, "tags/"))
                return 1;
 
        /* All type bits clear means that we are ok with anything */
@@ -39,72 +41,166 @@ static int check_ref(const char *name, int len, unsigned int flags)
 
 int check_ref_type(const struct ref *ref, int flags)
 {
-       return check_ref(ref->name, strlen(ref->name), flags);
+       return check_ref(ref->name, flags);
+}
+
+static void die_initial_contact(int unexpected)
+{
+       if (unexpected)
+               die(_("The remote end hung up upon initial contact"));
+       else
+               die(_("Could not read from remote repository.\n\n"
+                     "Please make sure you have the correct access rights\n"
+                     "and the repository exists."));
 }
 
-static void add_extra_have(struct extra_have_objects *extra, unsigned char *sha1)
+static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 {
-       ALLOC_GROW(extra->array, extra->nr + 1, extra->alloc);
-       hashcpy(&(extra->array[extra->nr][0]), sha1);
-       extra->nr++;
+       char *sym, *target;
+       struct string_list_item *item;
+
+       if (!len)
+               return; /* just "symref" */
+       /* e.g. "symref=HEAD:refs/heads/master" */
+       sym = xmemdupz(val, len);
+       target = strchr(sym, ':');
+       if (!target)
+               /* just "symref=something" */
+               goto reject;
+       *(target++) = '\0';
+       if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
+           check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
+               /* "symref=bogus:pair */
+               goto reject;
+       item = string_list_append_nodup(symref, sym);
+       item->util = target;
+       return;
+reject:
+       free(sym);
+       return;
+}
+
+static void annotate_refs_with_symref_info(struct ref *ref)
+{
+       struct string_list symref = STRING_LIST_INIT_DUP;
+       const char *feature_list = server_capabilities;
+
+       while (feature_list) {
+               int len;
+               const char *val;
+
+               val = parse_feature_value(feature_list, "symref", &len);
+               if (!val)
+                       break;
+               parse_one_symref_info(&symref, val, len);
+               feature_list = val + 1;
+       }
+       string_list_sort(&symref);
+
+       for (; ref; ref = ref->next) {
+               struct string_list_item *item;
+               item = string_list_lookup(&symref, ref->name);
+               if (!item)
+                       continue;
+               ref->symref = xstrdup((char *)item->util);
+       }
+       string_list_clear(&symref, 0);
 }
 
 /*
  * Read all the refs from the other end
  */
-struct ref **get_remote_heads(int in, struct ref **list,
-                             unsigned int flags,
-                             struct extra_have_objects *extra_have)
+struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
+                             struct ref **list, unsigned int flags,
+                             struct oid_array *extra_have,
+                             struct oid_array *shallow_points)
 {
+       struct ref **orig_list = list;
+
+       /*
+        * A hang-up after seeing some response from the other end
+        * means that it is unexpected, as we know the other end is
+        * willing to talk to us.  A hang-up before seeing any
+        * response does not necessarily mean an ACL problem, though.
+        */
+       int saw_response;
+       int got_dummy_ref_with_capabilities_declaration = 0;
+
        *list = NULL;
-       for (;;) {
+       for (saw_response = 0; ; saw_response = 1) {
                struct ref *ref;
-               unsigned char old_sha1[20];
-               static char buffer[1000];
+               struct object_id old_oid;
                char *name;
                int len, name_len;
+               char *buffer = packet_buffer;
+               const char *arg;
+
+               len = packet_read(in, &src_buf, &src_len,
+                                 packet_buffer, sizeof(packet_buffer),
+                                 PACKET_READ_GENTLE_ON_EOF |
+                                 PACKET_READ_CHOMP_NEWLINE);
+               if (len < 0)
+                       die_initial_contact(saw_response);
 
-               len = packet_read_line(in, buffer, sizeof(buffer));
                if (!len)
                        break;
-               if (buffer[len-1] == '\n')
-                       buffer[--len] = 0;
 
-               if (len > 4 && !prefixcmp(buffer, "ERR "))
-                       die("remote error: %s", buffer + 4);
+               if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
+                       die("remote error: %s", arg);
+
+               if (len == GIT_SHA1_HEXSZ + strlen("shallow ") &&
+                       skip_prefix(buffer, "shallow ", &arg)) {
+                       if (get_oid_hex(arg, &old_oid))
+                               die("protocol error: expected shallow sha-1, got '%s'", arg);
+                       if (!shallow_points)
+                               die("repository on the other end cannot be shallow");
+                       oid_array_append(shallow_points, &old_oid);
+                       continue;
+               }
 
-               if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
+               if (len < GIT_SHA1_HEXSZ + 2 || get_oid_hex(buffer, &old_oid) ||
+                       buffer[GIT_SHA1_HEXSZ] != ' ')
                        die("protocol error: expected sha/ref, got '%s'", buffer);
-               name = buffer + 41;
+               name = buffer + GIT_SHA1_HEXSZ + 1;
 
                name_len = strlen(name);
-               if (len != name_len + 41) {
+               if (len != name_len + GIT_SHA1_HEXSZ + 1) {
                        free(server_capabilities);
                        server_capabilities = xstrdup(name + name_len + 1);
                }
 
-               if (extra_have &&
-                   name_len == 5 && !memcmp(".have", name, 5)) {
-                       add_extra_have(extra_have, old_sha1);
+               if (extra_have && !strcmp(name, ".have")) {
+                       oid_array_append(extra_have, &old_oid);
+                       continue;
+               }
+
+               if (!strcmp(name, "capabilities^{}")) {
+                       if (saw_response)
+                               die("protocol error: unexpected capabilities^{}");
+                       if (got_dummy_ref_with_capabilities_declaration)
+                               die("protocol error: multiple capabilities^{}");
+                       got_dummy_ref_with_capabilities_declaration = 1;
                        continue;
                }
 
-               if (!check_ref(name, name_len, flags))
+               if (!check_ref(name, flags))
                        continue;
-               ref = alloc_ref(buffer + 41);
-               hashcpy(ref->old_sha1, old_sha1);
+
+               if (got_dummy_ref_with_capabilities_declaration)
+                       die("protocol error: unexpected ref after capabilities^{}");
+
+               ref = alloc_ref(buffer + GIT_SHA1_HEXSZ + 1);
+               oidcpy(&ref->old_oid, &old_oid);
                *list = ref;
                list = &ref->next;
        }
-       return list;
-}
 
-int server_supports(const char *feature)
-{
-       return !!parse_feature_request(server_capabilities, feature);
+       annotate_refs_with_symref_info(*orig_list);
+
+       return list;
 }
 
-const char *parse_feature_request(const char *feature_list, const char *feature)
+static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 {
        int len;
 
@@ -116,57 +212,131 @@ const char *parse_feature_request(const char *feature_list, const char *feature)
                const char *found = strstr(feature_list, feature);
                if (!found)
                        return NULL;
-               if ((feature_list == found || isspace(found[-1])) &&
-                   (!found[len] || isspace(found[len]) || found[len] == '='))
-                       return found;
+               if (feature_list == found || isspace(found[-1])) {
+                       const char *value = found + len;
+                       /* feature with no value (e.g., "thin-pack") */
+                       if (!*value || isspace(*value)) {
+                               if (lenp)
+                                       *lenp = 0;
+                               return value;
+                       }
+                       /* feature with a value (e.g., "agent=git/1.2.3") */
+                       else if (*value == '=') {
+                               value++;
+                               if (lenp)
+                                       *lenp = strcspn(value, " \t\n");
+                               return value;
+                       }
+                       /*
+                        * otherwise we matched a substring of another feature;
+                        * keep looking
+                        */
+               }
                feature_list = found + 1;
        }
        return NULL;
 }
 
+int parse_feature_request(const char *feature_list, const char *feature)
+{
+       return !!parse_feature_value(feature_list, feature, NULL);
+}
+
+const char *server_feature_value(const char *feature, int *len)
+{
+       return parse_feature_value(server_capabilities, feature, len);
+}
+
+int server_supports(const char *feature)
+{
+       return !!server_feature_value(feature, NULL);
+}
+
 enum protocol {
        PROTO_LOCAL = 1,
+       PROTO_FILE,
        PROTO_SSH,
        PROTO_GIT
 };
 
+int url_is_local_not_ssh(const char *url)
+{
+       const char *colon = strchr(url, ':');
+       const char *slash = strchr(url, '/');
+       return !colon || (slash && slash < colon) ||
+               has_dos_drive_prefix(url);
+}
+
+static const char *prot_name(enum protocol protocol)
+{
+       switch (protocol) {
+               case PROTO_LOCAL:
+               case PROTO_FILE:
+                       return "file";
+               case PROTO_SSH:
+                       return "ssh";
+               case PROTO_GIT:
+                       return "git";
+               default:
+                       return "unknown protocol";
+       }
+}
+
 static enum protocol get_protocol(const char *name)
 {
        if (!strcmp(name, "ssh"))
                return PROTO_SSH;
        if (!strcmp(name, "git"))
                return PROTO_GIT;
-       if (!strcmp(name, "git+ssh"))
+       if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
                return PROTO_SSH;
-       if (!strcmp(name, "ssh+git"))
+       if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
                return PROTO_SSH;
        if (!strcmp(name, "file"))
-               return PROTO_LOCAL;
+               return PROTO_FILE;
        die("I don't handle protocol '%s'", name);
 }
 
+static char *host_end(char **hoststart, int removebrackets)
+{
+       char *host = *hoststart;
+       char *end;
+       char *start = strstr(host, "@[");
+       if (start)
+               start++; /* Jump over '@' */
+       else
+               start = host;
+       if (start[0] == '[') {
+               end = strchr(start + 1, ']');
+               if (end) {
+                       if (removebrackets) {
+                               *end = 0;
+                               memmove(start, start + 1, end - start);
+                               end++;
+                       }
+               } else
+                       end = host;
+       } else
+               end = host;
+       return end;
+}
+
 #define STR_(s)        # s
 #define STR(s) STR_(s)
 
 static void get_host_and_port(char **host, const char **port)
 {
        char *colon, *end;
-
-       if (*host[0] == '[') {
-               end = strchr(*host + 1, ']');
-               if (end) {
-                       *end = 0;
-                       end++;
-                       (*host)++;
-               } else
-                       end = *host;
-       } else
-               end = *host;
+       end = host_end(host, 1);
        colon = strchr(end, ':');
-
        if (colon) {
-               *colon = 0;
-               *port = colon + 1;
+               long portnr = strtol(colon + 1, &end, 10);
+               if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
+                       *colon = 0;
+                       *port = colon + 1;
+               } else if (!colon[1]) {
+                       *colon = 0;
+               }
        }
 }
 
@@ -186,7 +356,7 @@ static const char *ai_name(const struct addrinfo *ai)
        static char addr[NI_MAXHOST];
        if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
                        NI_NUMERICHOST) != 0)
-               strcpy(addr, "(unknown)");
+               xsnprintf(addr, sizeof(addr), "(unknown)");
 
        return addr;
 }
@@ -208,6 +378,10 @@ static int git_tcp_connect_sock(char *host, int flags)
                port = "<none>";
 
        memset(&hints, 0, sizeof(hints));
+       if (flags & CONNECT_IPV4)
+               hints.ai_family = AF_INET;
+       else if (flags & CONNECT_IPV6)
+               hints.ai_family = AF_INET6;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = IPPROTO_TCP;
 
@@ -400,29 +574,29 @@ static int git_use_proxy(const char *host)
 static struct child_process *git_proxy_connect(int fd[2], char *host)
 {
        const char *port = STR(DEFAULT_GIT_PORT);
-       const char **argv;
        struct child_process *proxy;
 
        get_host_and_port(&host, &port);
 
-       argv = xmalloc(sizeof(*argv) * 4);
-       argv[0] = git_proxy_command;
-       argv[1] = host;
-       argv[2] = port;
-       argv[3] = NULL;
-       proxy = xcalloc(1, sizeof(*proxy));
-       proxy->argv = argv;
+       if (looks_like_command_line_option(host))
+               die("strange hostname '%s' blocked", host);
+       if (looks_like_command_line_option(port))
+               die("strange port '%s' blocked", port);
+
+       proxy = xmalloc(sizeof(*proxy));
+       child_process_init(proxy);
+       argv_array_push(&proxy->args, git_proxy_command);
+       argv_array_push(&proxy->args, host);
+       argv_array_push(&proxy->args, port);
        proxy->in = -1;
        proxy->out = -1;
        if (start_command(proxy))
-               die("cannot start proxy %s", argv[0]);
+               die("cannot start proxy %s", git_proxy_command);
        fd[0] = proxy->out; /* read from proxy stdout */
        fd[1] = proxy->in;  /* write to proxy stdin */
        return proxy;
 }
 
-#define MAX_CMD_LEN 1024
-
 static char *get_port(char *host)
 {
        char *end;
@@ -439,37 +613,18 @@ static char *get_port(char *host)
        return NULL;
 }
 
-static struct child_process no_fork;
-
 /*
- * This returns a dummy child_process if the transport protocol does not
- * need fork(2), or a struct child_process object if it does.  Once done,
- * finish the connection with finish_connect() with the value returned from
- * this function (it is safe to call finish_connect() with NULL to support
- * the former case).
- *
- * If it returns, the connect is successful; it just dies on errors (this
- * will hopefully be changed in a libification effort, to return NULL when
- * the connection failed).
+ * Extract protocol and relevant parts from the specified connection URL.
+ * The caller must free() the returned strings.
  */
-struct child_process *git_connect(int fd[2], const char *url_orig,
-                                 const char *prog, int flags)
+static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
+                                      char **ret_path)
 {
        char *url;
        char *host, *path;
        char *end;
-       int c;
-       struct child_process *conn = &no_fork;
+       int separator = '/';
        enum protocol protocol = PROTO_LOCAL;
-       int free_path = 0;
-       char *port = NULL;
-       const char **arg;
-       struct strbuf cmd;
-
-       /* Without this we cannot rely on waitpid() to tell
-        * what happened to our children.
-        */
-       signal(SIGCHLD, SIG_DFL);
 
        if (is_url(url_orig))
                url = url_decode(url_orig);
@@ -481,37 +636,26 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
                *host = '\0';
                protocol = get_protocol(url);
                host += 3;
-               c = '/';
        } else {
                host = url;
-               c = ':';
+               if (!url_is_local_not_ssh(url)) {
+                       protocol = PROTO_SSH;
+                       separator = ':';
+               }
        }
 
        /*
-        * Don't do destructive transforms with git:// as that
-        * protocol code does '[]' unwrapping of its own.
+        * Don't do destructive transforms as protocol code does
+        * '[]' unwrapping in get_host_and_port()
         */
-       if (host[0] == '[') {
-               end = strchr(host + 1, ']');
-               if (end) {
-                       if (protocol != PROTO_GIT) {
-                               *end = 0;
-                               host++;
-                       }
-                       end++;
-               } else
-                       end = host;
-       } else
-               end = host;
+       end = host_end(&host, 0);
 
-       path = strchr(end, c);
-       if (path && !has_dos_drive_prefix(end)) {
-               if (c == ':') {
-                       protocol = PROTO_SSH;
-                       *path++ = '\0';
-               }
-       } else
+       if (protocol == PROTO_LOCAL)
                path = end;
+       else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
+               path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
+       else
+               path = strchr(end, separator);
 
        if (!path || !*path)
                die("No path specified. See 'man git-pull' for valid url syntax");
@@ -520,33 +664,155 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
         * null-terminate hostname and point path to ~ for URL's like this:
         *    ssh://host.xz/~user/repo
         */
-       if (protocol != PROTO_LOCAL && host != url) {
-               char *ptr = path;
+
+       end = path; /* Need to \0 terminate host here */
+       if (separator == ':')
+               path++; /* path starts after ':' */
+       if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
                if (path[1] == '~')
                        path++;
-               else {
-                       path = xstrdup(ptr);
-                       free_path = 1;
+       }
+
+       path = xstrdup(path);
+       *end = '\0';
+
+       *ret_host = xstrdup(host);
+       *ret_path = path;
+       free(url);
+       return protocol;
+}
+
+static struct child_process no_fork = CHILD_PROCESS_INIT;
+
+static const char *get_ssh_command(void)
+{
+       const char *ssh;
+
+       if ((ssh = getenv("GIT_SSH_COMMAND")))
+               return ssh;
+
+       if (!git_config_get_string_const("core.sshcommand", &ssh))
+               return ssh;
+
+       return NULL;
+}
+
+static int override_ssh_variant(int *port_option, int *needs_batch)
+{
+       char *variant;
+
+       variant = xstrdup_or_null(getenv("GIT_SSH_VARIANT"));
+       if (!variant &&
+           git_config_get_string("ssh.variant", &variant))
+               return 0;
+
+       if (!strcmp(variant, "plink") || !strcmp(variant, "putty")) {
+               *port_option = 'P';
+               *needs_batch = 0;
+       } else if (!strcmp(variant, "tortoiseplink")) {
+               *port_option = 'P';
+               *needs_batch = 1;
+       } else {
+               *port_option = 'p';
+               *needs_batch = 0;
+       }
+       free(variant);
+       return 1;
+}
+
+static void handle_ssh_variant(const char *ssh_command, int is_cmdline,
+                              int *port_option, int *needs_batch)
+{
+       const char *variant;
+       char *p = NULL;
+
+       if (override_ssh_variant(port_option, needs_batch))
+               return;
+
+       if (!is_cmdline) {
+               p = xstrdup(ssh_command);
+               variant = basename(p);
+       } else {
+               const char **ssh_argv;
+
+               p = xstrdup(ssh_command);
+               if (split_cmdline(p, &ssh_argv) > 0) {
+                       variant = basename((char *)ssh_argv[0]);
+                       /*
+                        * At this point, variant points into the buffer
+                        * referenced by p, hence we do not need ssh_argv
+                        * any longer.
+                        */
+                       free(ssh_argv);
+               } else {
+                       free(p);
+                       return;
                }
+       }
 
-               *ptr = '\0';
+       if (!strcasecmp(variant, "plink") ||
+           !strcasecmp(variant, "plink.exe"))
+               *port_option = 'P';
+       else if (!strcasecmp(variant, "tortoiseplink") ||
+                !strcasecmp(variant, "tortoiseplink.exe")) {
+               *port_option = 'P';
+               *needs_batch = 1;
        }
+       free(p);
+}
 
-       /*
-        * Add support for ssh port: ssh://host.xy:<port>/...
+/*
+ * This returns a dummy child_process if the transport protocol does not
+ * need fork(2), or a struct child_process object if it does.  Once done,
+ * finish the connection with finish_connect() with the value returned from
+ * this function (it is safe to call finish_connect() with NULL to support
+ * the former case).
+ *
+ * If it returns, the connect is successful; it just dies on errors (this
+ * will hopefully be changed in a libification effort, to return NULL when
+ * the connection failed).
+ */
+struct child_process *git_connect(int fd[2], const char *url,
+                                 const char *prog, int flags)
+{
+       char *hostandport, *path;
+       struct child_process *conn = &no_fork;
+       enum protocol protocol;
+       struct strbuf cmd = STRBUF_INIT;
+
+       /* Without this we cannot rely on waitpid() to tell
+        * what happened to our children.
         */
-       if (protocol == PROTO_SSH && host != url)
-               port = get_port(host);
+       signal(SIGCHLD, SIG_DFL);
+
+       protocol = parse_connect_url(url, &hostandport, &path);
+       if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
+               printf("Diag: url=%s\n", url ? url : "NULL");
+               printf("Diag: protocol=%s\n", prot_name(protocol));
+               printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
+               printf("Diag: path=%s\n", path ? path : "NULL");
+               conn = NULL;
+       } else if (protocol == PROTO_GIT) {
+               /*
+                * Set up virtual host information based on where we will
+                * connect, unless the user has overridden us in
+                * the environment.
+                */
+               char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
+               if (target_host)
+                       target_host = xstrdup(target_host);
+               else
+                       target_host = xstrdup(hostandport);
+
+               transport_check_allowed("git");
 
-       if (protocol == PROTO_GIT) {
                /* These underlying connection commands die() if they
                 * cannot connect.
                 */
-               char *target_host = xstrdup(host);
-               if (git_use_proxy(host))
-                       conn = git_proxy_connect(fd, host);
+               if (git_use_proxy(hostandport))
+                       conn = git_proxy_connect(fd, hostandport);
                else
-                       git_tcp_connect(fd, host, flags);
+                       git_tcp_connect(fd, hostandport, flags);
                /*
                 * Separate original protocol components prog and path
                 * from extended host header with a NUL byte.
@@ -554,60 +820,102 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
                 * Note: Do not add any other headers here!  Doing so
                 * will cause older git-daemon servers to crash.
                 */
-               packet_write(fd[1],
+               packet_write_fmt(fd[1],
                             "%s %s%chost=%s%c",
                             prog, path, 0,
                             target_host, 0);
                free(target_host);
-               free(url);
-               if (free_path)
-                       free(path);
-               return conn;
-       }
+       } else {
+               conn = xmalloc(sizeof(*conn));
+               child_process_init(conn);
+
+               if (looks_like_command_line_option(path))
+                       die("strange pathname '%s' blocked", path);
+
+               strbuf_addstr(&cmd, prog);
+               strbuf_addch(&cmd, ' ');
+               sq_quote_buf(&cmd, path);
 
-       conn = xcalloc(1, sizeof(*conn));
-
-       strbuf_init(&cmd, MAX_CMD_LEN);
-       strbuf_addstr(&cmd, prog);
-       strbuf_addch(&cmd, ' ');
-       sq_quote_buf(&cmd, path);
-       if (cmd.len >= MAX_CMD_LEN)
-               die("command line too long");
-
-       conn->in = conn->out = -1;
-       conn->argv = arg = xcalloc(7, sizeof(*arg));
-       if (protocol == PROTO_SSH) {
-               const char *ssh = getenv("GIT_SSH");
-               int putty = ssh && strcasestr(ssh, "plink");
-               if (!ssh) ssh = "ssh";
-
-               *arg++ = ssh;
-               if (putty && !strcasestr(ssh, "tortoiseplink"))
-                       *arg++ = "-batch";
-               if (port) {
-                       /* P is for PuTTY, p is for OpenSSH */
-                       *arg++ = putty ? "-P" : "-p";
-                       *arg++ = port;
-               }
-               *arg++ = host;
-       }
-       else {
                /* remove repo-local variables from the environment */
                conn->env = local_repo_env;
                conn->use_shell = 1;
-       }
-       *arg++ = cmd.buf;
-       *arg = NULL;
+               conn->in = conn->out = -1;
+               if (protocol == PROTO_SSH) {
+                       const char *ssh;
+                       int needs_batch = 0;
+                       int port_option = 'p';
+                       char *ssh_host = hostandport;
+                       const char *port = NULL;
+                       transport_check_allowed("ssh");
+                       get_host_and_port(&ssh_host, &port);
+
+                       if (!port)
+                               port = get_port(ssh_host);
+
+                       if (flags & CONNECT_DIAG_URL) {
+                               printf("Diag: url=%s\n", url ? url : "NULL");
+                               printf("Diag: protocol=%s\n", prot_name(protocol));
+                               printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
+                               printf("Diag: port=%s\n", port ? port : "NONE");
+                               printf("Diag: path=%s\n", path ? path : "NULL");
+
+                               free(hostandport);
+                               free(path);
+                               free(conn);
+                               return NULL;
+                       }
 
-       if (start_command(conn))
-               die("unable to fork");
+                       if (looks_like_command_line_option(ssh_host))
+                               die("strange hostname '%s' blocked", ssh_host);
+
+                       ssh = get_ssh_command();
+                       if (ssh)
+                               handle_ssh_variant(ssh, 1, &port_option,
+                                                  &needs_batch);
+                       else {
+                               /*
+                                * GIT_SSH is the no-shell version of
+                                * GIT_SSH_COMMAND (and must remain so for
+                                * historical compatibility).
+                                */
+                               conn->use_shell = 0;
+
+                               ssh = getenv("GIT_SSH");
+                               if (!ssh)
+                                       ssh = "ssh";
+                               else
+                                       handle_ssh_variant(ssh, 0,
+                                                          &port_option,
+                                                          &needs_batch);
+                       }
 
-       fd[0] = conn->out; /* read from child's stdout */
-       fd[1] = conn->in;  /* write to child's stdin */
-       strbuf_release(&cmd);
-       free(url);
-       if (free_path)
-               free(path);
+                       argv_array_push(&conn->args, ssh);
+                       if (flags & CONNECT_IPV4)
+                               argv_array_push(&conn->args, "-4");
+                       else if (flags & CONNECT_IPV6)
+                               argv_array_push(&conn->args, "-6");
+                       if (needs_batch)
+                               argv_array_push(&conn->args, "-batch");
+                       if (port) {
+                               argv_array_pushf(&conn->args,
+                                                "-%c", port_option);
+                               argv_array_push(&conn->args, port);
+                       }
+                       argv_array_push(&conn->args, ssh_host);
+               } else {
+                       transport_check_allowed("file");
+               }
+               argv_array_push(&conn->args, cmd.buf);
+
+               if (start_command(conn))
+                       die("unable to fork");
+
+               fd[0] = conn->out; /* read from child's stdout */
+               fd[1] = conn->in;  /* write to child's stdin */
+               strbuf_release(&cmd);
+       }
+       free(hostandport);
+       free(path);
        return conn;
 }
 
@@ -623,7 +931,6 @@ int finish_connect(struct child_process *conn)
                return 0;
 
        code = finish_command(conn);
-       free(conn->argv);
        free(conn);
        return code;
 }