/src/git/connect.c

Source (jump to first uncovered line)
#include "git-compat-util.h"
#include "config.h"
#include "environment.h"
#include "gettext.h"
#include "hex.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 "oid-array.h"
#include "path.h"
#include "transport.h"
#include "trace2.h"
#include "strbuf.h"
#include "version.h"
#include "protocol.h"
#include "alias.h"
#include "bundle-uri.h"

static char *server_capabilities_v1;
static struct strvec server_capabilities_v2 = STRVEC_INIT;
static const char *next_server_feature_value(const char *feature, size_t *len, size_t *offset);

static int check_ref(const char *name, unsigned int flags)
{
  if (!flags)
    return 1;

  if (!skip_prefix(name, "refs/", &name))
    return 0;

  /* REF_NORMAL means that we don't want the magic fake tag refs */
  if ((flags & REF_NORMAL) && check_refname_format(name,
               REFNAME_ALLOW_ONELEVEL))
    return 0;

  /* REF_HEADS means that we want regular branch heads */
  if ((flags & REF_HEADS) && starts_with(name, "heads/"))
    return 1;

  /* REF_TAGS means that we want tags */
  if ((flags & REF_TAGS) && starts_with(name, "tags/"))
    return 1;

  /* All type bits clear means that we are ok with anything */
  return !(flags & ~REF_NORMAL);
}

int check_ref_type(const struct ref *ref, int flags)
{
  return check_ref(ref->name, flags);
}

static NORETURN void die_initial_contact(int unexpected)
{
  /*
   * 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.
   */
  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."));
}

/* Checks if the server supports the capability 'c' */
int server_supports_v2(const char *c)
{
  int i;

  for (i = 0; i < server_capabilities_v2.nr; i++) {
    const char *out;
    if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
        (!*out || *out == '='))
      return 1;
  }
  return 0;
}

void ensure_server_supports_v2(const char *c)
{
  if (!server_supports_v2(c))
    die(_("server doesn't support '%s'"), c);
}

int server_feature_v2(const char *c, const char **v)
{
  int i;

  for (i = 0; i < server_capabilities_v2.nr; i++) {
    const char *out;
    if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
        (*out == '=')) {
      *v = out + 1;
      return 1;
    }
  }
  return 0;
}

int server_supports_feature(const char *c, const char *feature,
          int die_on_error)
{
  int i;

  for (i = 0; i < server_capabilities_v2.nr; i++) {
    const char *out;
    if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
        (!*out || *(out++) == '=')) {
      if (parse_feature_request(out, feature))
        return 1;
      else
        break;
    }
  }

  if (die_on_error)
    die(_("server doesn't support feature '%s'"), feature);

  return 0;
}

static void process_capabilities_v2(struct packet_reader *reader)
{
  while (packet_reader_read(reader) == PACKET_READ_NORMAL)
    strvec_push(&server_capabilities_v2, reader->line);

  if (reader->status != PACKET_READ_FLUSH)
    die(_("expected flush after capabilities"));
}

enum protocol_version discover_version(struct packet_reader *reader)
{
  enum protocol_version version = protocol_unknown_version;

  /*
   * Peek the first line of the server's response to
   * determine the protocol version the server is speaking.
   */
  switch (packet_reader_peek(reader)) {
  case PACKET_READ_EOF:
    die_initial_contact(0);
  case PACKET_READ_FLUSH:
  case PACKET_READ_DELIM:
  case PACKET_READ_RESPONSE_END:
    version = protocol_v0;
    break;
  case PACKET_READ_NORMAL:
    version = determine_protocol_version_client(reader->line);
    break;
  }

  switch (version) {
  case protocol_v2:
    process_capabilities_v2(reader);
    break;
  case protocol_v1:
    /* Read the peeked version line */
    packet_reader_read(reader);
    break;
  case protocol_v0:
    break;
  case protocol_unknown_version:
    BUG("unknown protocol version");
  }

  trace2_data_intmax("transfer", NULL, "negotiated-version", version);

  return version;
}

static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
{
  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;
  size_t offset = 0;

  while (1) {
    size_t len;
    const char *val;

    val = next_server_feature_value("symref", &len, &offset);
    if (!val)
      break;
    parse_one_symref_info(&symref, val, len);
  }
  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);
}

static void process_capabilities(struct packet_reader *reader, int *linelen)
{
  const char *feat_val;
  size_t feat_len;
  const char *line = reader->line;
  int nul_location = strlen(line);
  if (nul_location == *linelen)
    return;
  server_capabilities_v1 = xstrdup(line + nul_location + 1);
  *linelen = nul_location;

  feat_val = server_feature_value("object-format", &feat_len);
  if (feat_val) {
    char *hash_name = xstrndup(feat_val, feat_len);
    int hash_algo = hash_algo_by_name(hash_name);
    if (hash_algo != GIT_HASH_UNKNOWN)
      reader->hash_algo = &hash_algos[hash_algo];
    free(hash_name);
  } else {
    reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
  }
}

static int process_dummy_ref(const struct packet_reader *reader)
{
  const char *line = reader->line;
  struct object_id oid;
  const char *name;

  if (parse_oid_hex_algop(line, &oid, &name, reader->hash_algo))
    return 0;
  if (*name != ' ')
    return 0;
  name++;

  return oideq(reader->hash_algo->null_oid, &oid) &&
    !strcmp(name, "capabilities^{}");
}

static void check_no_capabilities(const char *line, int len)
{
  if (strlen(line) != len)
    warning(_("ignoring capabilities after first line '%s'"),
      line + strlen(line));
}

static int process_ref(const struct packet_reader *reader, int len,
           struct ref ***list, unsigned int flags,
           struct oid_array *extra_have)
{
  const char *line = reader->line;
  struct object_id old_oid;
  const char *name;

  if (parse_oid_hex_algop(line, &old_oid, &name, reader->hash_algo))
    return 0;
  if (*name != ' ')
    return 0;
  name++;

  if (extra_have && !strcmp(name, ".have")) {
    oid_array_append(extra_have, &old_oid);
  } else if (!strcmp(name, "capabilities^{}")) {
    die(_("protocol error: unexpected capabilities^{}"));
  } else if (check_ref(name, flags)) {
    struct ref *ref = alloc_ref(name);
    oidcpy(&ref->old_oid, &old_oid);
    **list = ref;
    *list = &ref->next;
  }
  check_no_capabilities(line, len);
  return 1;
}

static int process_shallow(const struct packet_reader *reader, int len,
         struct oid_array *shallow_points)
{
  const char *line = reader->line;
  const char *arg;
  struct object_id old_oid;

  if (!skip_prefix(line, "shallow ", &arg))
    return 0;

  if (get_oid_hex_algop(arg, &old_oid, reader->hash_algo))
    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);
  check_no_capabilities(line, len);
  return 1;
}

enum get_remote_heads_state {
  EXPECTING_FIRST_REF = 0,
  EXPECTING_REF,
  EXPECTING_SHALLOW,
  EXPECTING_DONE,
};

/*
 * Read all the refs from the other end
 */
struct ref **get_remote_heads(struct packet_reader *reader,
            struct ref **list, unsigned int flags,
            struct oid_array *extra_have,
            struct oid_array *shallow_points)
{
  struct ref **orig_list = list;
  int len = 0;
  enum get_remote_heads_state state = EXPECTING_FIRST_REF;

  *list = NULL;

  while (state != EXPECTING_DONE) {
    switch (packet_reader_read(reader)) {
    case PACKET_READ_EOF:
      die_initial_contact(1);
    case PACKET_READ_NORMAL:
      len = reader->pktlen;
      break;
    case PACKET_READ_FLUSH:
      state = EXPECTING_DONE;
      break;
    case PACKET_READ_DELIM:
    case PACKET_READ_RESPONSE_END:
      die(_("invalid packet"));
    }

    switch (state) {
    case EXPECTING_FIRST_REF:
      process_capabilities(reader, &len);
      if (process_dummy_ref(reader)) {
        state = EXPECTING_SHALLOW;
        break;
      }
      state = EXPECTING_REF;
      /* fallthrough */
    case EXPECTING_REF:
      if (process_ref(reader, len, &list, flags, extra_have))
        break;
      state = EXPECTING_SHALLOW;
      /* fallthrough */
    case EXPECTING_SHALLOW:
      if (process_shallow(reader, len, shallow_points))
        break;
      die(_("protocol error: unexpected '%s'"), reader->line);
    case EXPECTING_DONE:
      break;
    }
  }

  annotate_refs_with_symref_info(*orig_list);

  return list;
}

/* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
static int process_ref_v2(struct packet_reader *reader, struct ref ***list,
        const char **unborn_head_target)
{
  int ret = 1;
  int i = 0;
  struct object_id old_oid;
  struct ref *ref;
  struct string_list line_sections = STRING_LIST_INIT_DUP;
  const char *end;
  const char *line = reader->line;

  /*
   * Ref lines have a number of fields which are space deliminated.  The
   * first field is the OID of the ref.  The second field is the ref
   * name.  Subsequent fields (symref-target and peeled) are optional and
   * don't have a particular order.
   */
  if (string_list_split(&line_sections, line, ' ', -1) < 2) {
    ret = 0;
    goto out;
  }

  if (!strcmp("unborn", line_sections.items[i].string)) {
    i++;
    if (unborn_head_target &&
        !strcmp("HEAD", line_sections.items[i++].string)) {
      /*
       * Look for the symref target (if any). If found,
       * return it to the caller.
       */
      for (; i < line_sections.nr; i++) {
        const char *arg = line_sections.items[i].string;

        if (skip_prefix(arg, "symref-target:", &arg)) {
          *unborn_head_target = xstrdup(arg);
          break;
        }
      }
    }
    goto out;
  }
  if (parse_oid_hex_algop(line_sections.items[i++].string, &old_oid, &end, reader->hash_algo) ||
      *end) {
    ret = 0;
    goto out;
  }

  ref = alloc_ref(line_sections.items[i++].string);

  memcpy(ref->old_oid.hash, old_oid.hash, reader->hash_algo->rawsz);
  **list = ref;
  *list = &ref->next;

  for (; i < line_sections.nr; i++) {
    const char *arg = line_sections.items[i].string;
    if (skip_prefix(arg, "symref-target:", &arg))
      ref->symref = xstrdup(arg);

    if (skip_prefix(arg, "peeled:", &arg)) {
      struct object_id peeled_oid;
      char *peeled_name;
      struct ref *peeled;
      if (parse_oid_hex_algop(arg, &peeled_oid, &end,
            reader->hash_algo) || *end) {
        ret = 0;
        goto out;
      }

      peeled_name = xstrfmt("%s^{}", ref->name);
      peeled = alloc_ref(peeled_name);

      memcpy(peeled->old_oid.hash, peeled_oid.hash,
             reader->hash_algo->rawsz);
      **list = peeled;
      *list = &peeled->next;

      free(peeled_name);
    }
  }

out:
  string_list_clear(&line_sections, 0);
  return ret;
}

void check_stateless_delimiter(int stateless_rpc,
            struct packet_reader *reader,
            const char *error)
{
  if (!stateless_rpc)
    return; /* not in stateless mode, no delimiter expected */
  if (packet_reader_read(reader) != PACKET_READ_RESPONSE_END)
    die("%s", error);
}

static void send_capabilities(int fd_out, struct packet_reader *reader)
{
  const char *hash_name;

  if (server_supports_v2("agent"))
    packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());

  if (server_feature_v2("object-format", &hash_name)) {
    int hash_algo = hash_algo_by_name(hash_name);
    if (hash_algo == GIT_HASH_UNKNOWN)
      die(_("unknown object format '%s' specified by server"), hash_name);
    reader->hash_algo = &hash_algos[hash_algo];
    packet_write_fmt(fd_out, "object-format=%s", reader->hash_algo->name);
  } else {
    reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
  }
}

int get_remote_bundle_uri(int fd_out, struct packet_reader *reader,
        struct bundle_list *bundles, int stateless_rpc)
{
  int line_nr = 1;

  /* Assert bundle-uri support */
  ensure_server_supports_v2("bundle-uri");

  /* (Re-)send capabilities */
  send_capabilities(fd_out, reader);

  /* Send command */
  packet_write_fmt(fd_out, "command=bundle-uri\n");
  packet_delim(fd_out);

  packet_flush(fd_out);

  /* Process response from server */
  while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
    const char *line = reader->line;
    line_nr++;

    if (!bundle_uri_parse_line(bundles, line))
      continue;

    return error(_("error on bundle-uri response line %d: %s"),
           line_nr, line);
  }

  if (reader->status != PACKET_READ_FLUSH)
    return error(_("expected flush after bundle-uri listing"));

  /*
   * Might die(), but obscure enough that that's OK, e.g. in
   * serve.c we'll call BUG() on its equivalent (the
   * PACKET_READ_RESPONSE_END check).
   */
  check_stateless_delimiter(stateless_rpc, reader,
          _("expected response end packet after ref listing"));

  return 0;
}

struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
           struct ref **list, int for_push,
           struct transport_ls_refs_options *transport_options,
           const struct string_list *server_options,
           int stateless_rpc)
{
  int i;
  struct strvec *ref_prefixes = transport_options ?
    &transport_options->ref_prefixes : NULL;
  const char **unborn_head_target = transport_options ?
    &transport_options->unborn_head_target : NULL;
  *list = NULL;

  ensure_server_supports_v2("ls-refs");
  packet_write_fmt(fd_out, "command=ls-refs\n");

  /* Send capabilities */
  send_capabilities(fd_out, reader);

  if (server_options && server_options->nr) {
    ensure_server_supports_v2("server-option");
    for (i = 0; i < server_options->nr; i++)
      packet_write_fmt(fd_out, "server-option=%s",
           server_options->items[i].string);
  }

  packet_delim(fd_out);
  /* When pushing we don't want to request the peeled tags */
  if (!for_push)
    packet_write_fmt(fd_out, "peel\n");
  packet_write_fmt(fd_out, "symrefs\n");
  if (server_supports_feature("ls-refs", "unborn", 0))
    packet_write_fmt(fd_out, "unborn\n");
  for (i = 0; ref_prefixes && i < ref_prefixes->nr; i++) {
    packet_write_fmt(fd_out, "ref-prefix %s\n",
         ref_prefixes->v[i]);
  }
  packet_flush(fd_out);

  /* Process response from server */
  while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
    if (!process_ref_v2(reader, &list, unborn_head_target))
      die(_("invalid ls-refs response: %s"), reader->line);
  }

  if (reader->status != PACKET_READ_FLUSH)
    die(_("expected flush after ref listing"));

  check_stateless_delimiter(stateless_rpc, reader,
          _("expected response end packet after ref listing"));

  return list;
}

const char *parse_feature_value(const char *feature_list, const char *feature, size_t *lenp, size_t *offset)
{
  const char *orig_start = feature_list;
  size_t len;

  if (!feature_list)
    return NULL;

  len = strlen(feature);
  if (offset)
    feature_list += *offset;
  while (*feature_list) {
    const char *found = strstr(feature_list, feature);
    if (!found)
      return NULL;
    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;
        if (offset)
          *offset = found + len - orig_start;
        return value;
      }
      /* feature with a value (e.g., "agent=git/1.2.3") */
      else if (*value == '=') {
        size_t end;

        value++;
        end = strcspn(value, " \t\n");
        if (lenp)
          *lenp = end;
        if (offset)
          *offset = value + end - orig_start;
        return value;
      }
      /*
       * otherwise we matched a substring of another feature;
       * keep looking
       */
    }
    feature_list = found + 1;
  }
  return NULL;
}

int server_supports_hash(const char *desired, int *feature_supported)
{
  size_t offset = 0;
  size_t len;
  const char *hash;

  hash = next_server_feature_value("object-format", &len, &offset);
  if (feature_supported)
    *feature_supported = !!hash;
  if (!hash) {
    hash = hash_algos[GIT_HASH_SHA1].name;
    len = strlen(hash);
  }
  while (hash) {
    if (!xstrncmpz(desired, hash, len))
      return 1;

    hash = next_server_feature_value("object-format", &len, &offset);
  }
  return 0;
}

int parse_feature_request(const char *feature_list, const char *feature)
{
  return !!parse_feature_value(feature_list, feature, NULL, NULL);
}

static const char *next_server_feature_value(const char *feature, size_t *len, size_t *offset)
{
  return parse_feature_value(server_capabilities_v1, feature, len, offset);
}

const char *server_feature_value(const char *feature, size_t *len)
{
  return parse_feature_value(server_capabilities_v1, feature, len, NULL);
}

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) && is_valid_path(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")) /* deprecated - do not use */
    return PROTO_SSH;
  if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
    return PROTO_SSH;
  if (!strcmp(name, "file"))
    return PROTO_FILE;
  die(_("protocol '%s' is not supported"), 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;
  end = host_end(host, 1);
  colon = strchr(end, ':');
  if (colon) {
    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;
    }
  }
}

static void enable_keepalive(int sockfd)
{
  int ka = 1;

  if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
    error_errno(_("unable to set SO_KEEPALIVE on socket"));
}

#ifndef NO_IPV6

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)
    xsnprintf(addr, sizeof(addr), "(unknown)");

  return addr;
}

/*
 * Returns a connected socket() fd, or else die()s.
 */
static int git_tcp_connect_sock(char *host, int flags)
{
  struct strbuf error_message = STRBUF_INIT;
  int sockfd = -1;
  const char *port = STR(DEFAULT_GIT_PORT);
  struct addrinfo hints, *ai0, *ai;
  int gai;
  int cnt = 0;

  get_host_and_port(&host, &port);
  if (!*port)
    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;

  if (flags & CONNECT_VERBOSE)
    fprintf(stderr, _("Looking up %s ... "), host);

  gai = getaddrinfo(host, port, &hints, &ai);
  if (gai)
    die(_("unable to look up %s (port %s) (%s)"), host, port, gai_strerror(gai));

  if (flags & CONNECT_VERBOSE)
    /* TRANSLATORS: this is the end of "Looking up %s ... " */
    fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);

  for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
    sockfd = socket(ai->ai_family,
        ai->ai_socktype, ai->ai_protocol);
    if ((sockfd < 0) ||
        (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
      strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
            host, cnt, ai_name(ai), strerror(errno));
      if (0 <= sockfd)
        close(sockfd);
      sockfd = -1;
      continue;
    }
    if (flags & CONNECT_VERBOSE)
      fprintf(stderr, "%s ", ai_name(ai));
    break;
  }

  freeaddrinfo(ai0);

  if (sockfd < 0)
    die(_("unable to connect to %s:\n%s"), host, error_message.buf);

  enable_keepalive(sockfd);

  if (flags & CONNECT_VERBOSE)
    /* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
    fprintf_ln(stderr, _("done."));

  strbuf_release(&error_message);

  return sockfd;
}

#else /* NO_IPV6 */

/*
 * Returns a connected socket() fd, or else die()s.
 */
static int git_tcp_connect_sock(char *host, int flags)
{
  struct strbuf error_message = STRBUF_INIT;
  int sockfd = -1;
  const char *port = STR(DEFAULT_GIT_PORT);
  char *ep;
  struct hostent *he;
  struct sockaddr_in sa;
  char **ap;
  unsigned int nport;
  int cnt;

  get_host_and_port(&host, &port);

  if (flags & CONNECT_VERBOSE)
    fprintf(stderr, _("Looking up %s ... "), host);

  he = gethostbyname(host);
  if (!he)
    die(_("unable to look up %s (%s)"), host, hstrerror(h_errno));
  nport = strtoul(port, &ep, 10);
  if ( ep == port || *ep ) {
    /* Not numeric */
    struct servent *se = getservbyname(port,"tcp");
    if ( !se )
      die(_("unknown port %s"), port);
    nport = se->s_port;
  }

  if (flags & CONNECT_VERBOSE)
    /* TRANSLATORS: this is the end of "Looking up %s ... " */
    fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);

  for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
    memset(&sa, 0, sizeof sa);
    sa.sin_family = he->h_addrtype;
    sa.sin_port = htons(nport);
    memcpy(&sa.sin_addr, *ap, he->h_length);

    sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
    if ((sockfd < 0) ||
        connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
      strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
        host,
        cnt,
        inet_ntoa(*(struct in_addr *)&sa.sin_addr),
        strerror(errno));
      if (0 <= sockfd)
        close(sockfd);
      sockfd = -1;
      continue;
    }
    if (flags & CONNECT_VERBOSE)
      fprintf(stderr, "%s ",
        inet_ntoa(*(struct in_addr *)&sa.sin_addr));
    break;
  }

  if (sockfd < 0)
    die(_("unable to connect to %s:\n%s"), host, error_message.buf);

  enable_keepalive(sockfd);

  if (flags & CONNECT_VERBOSE)
    /* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
    fprintf_ln(stderr, _("done."));

  return sockfd;
}

#endif /* NO_IPV6 */


/*
 * Dummy child_process returned by git_connect() if the transport protocol
 * does not need fork(2).
 */
static struct child_process no_fork = CHILD_PROCESS_INIT;

int git_connection_is_socket(struct child_process *conn)
{
  return conn == &no_fork;
}

static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
{
  int sockfd = git_tcp_connect_sock(host, flags);

  fd[0] = sockfd;
  fd[1] = dup(sockfd);

  return &no_fork;
}


static char *git_proxy_command;

static int git_proxy_command_options(const char *var, const char *value,
    const struct config_context *ctx, void *cb)
{
  if (!strcmp(var, "core.gitproxy")) {
    const char *for_pos;
    int matchlen = -1;
    int hostlen;
    const char *rhost_name = cb;
    int rhost_len = strlen(rhost_name);

    if (git_proxy_command)
      return 0;
    if (!value)
      return config_error_nonbool(var);
    /* [core]
     * ;# matches www.kernel.org as well
     * gitproxy = netcatter-1 for kernel.org
     * gitproxy = netcatter-2 for sample.xz
     * gitproxy = netcatter-default
     */
    for_pos = strstr(value, " for ");
    if (!for_pos)
      /* matches everybody */
      matchlen = strlen(value);
    else {
      hostlen = strlen(for_pos + 5);
      if (rhost_len < hostlen)
        matchlen = -1;
      else if (!strncmp(for_pos + 5,
            rhost_name + rhost_len - hostlen,
            hostlen) &&
         ((rhost_len == hostlen) ||
          rhost_name[rhost_len - hostlen -1] == '.'))
        matchlen = for_pos - value;
      else
        matchlen = -1;
    }
    if (0 <= matchlen) {
      /* core.gitproxy = none for kernel.org */
      if (matchlen == 4 &&
          !memcmp(value, "none", 4))
        matchlen = 0;
      git_proxy_command = xmemdupz(value, matchlen);
    }
    return 0;
  }

  return git_default_config(var, value, ctx, cb);
}

static int git_use_proxy(const char *host)
{
  git_proxy_command = getenv("GIT_PROXY_COMMAND");
  git_config(git_proxy_command_options, (void*)host);
  return (git_proxy_command && *git_proxy_command);
}

static struct child_process *git_proxy_connect(int fd[2], char *host)
{
  const char *port = STR(DEFAULT_GIT_PORT);
  struct child_process *proxy;

  get_host_and_port(&host, &port);

  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);
  strvec_push(&proxy->args, git_proxy_command);
  strvec_push(&proxy->args, host);
  strvec_push(&proxy->args, port);
  proxy->in = -1;
  proxy->out = -1;
  if (start_command(proxy))
    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;
}

static char *get_port(char *host)
{
  char *end;
  char *p = strchr(host, ':');

  if (p) {
    long port = strtol(p + 1, &end, 10);
    if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
      *p = '\0';
      return p+1;
    }
  }

  return NULL;
}

/*
 * Extract protocol and relevant parts from the specified connection URL.
 * The caller must free() the returned strings.
 */
static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
               char **ret_path)
{
  char *url;
  char *host, *path;
  char *end;
  int separator = '/';
  enum protocol protocol = PROTO_LOCAL;

  if (is_url(url_orig))
    url = url_decode(url_orig);
  else
    url = xstrdup(url_orig);

  host = strstr(url, "://");
  if (host) {
    *host = '\0';
    protocol = get_protocol(url);
    host += 3;
  } else {
    host = url;
    if (!url_is_local_not_ssh(url)) {
      protocol = PROTO_SSH;
      separator = ':';
    }
  }

  /*
   * Don't do destructive transforms as protocol code does
   * '[]' unwrapping in get_host_and_port()
   */
  end = host_end(&host, 0);

  if (protocol == PROTO_LOCAL)
    path = end;
  else if (protocol == PROTO_FILE && *host != '/' &&
     !has_dos_drive_prefix(host) &&
     offset_1st_component(host - 2) > 1)
    path = host - 2; /* include the leading "//" */
  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 'git help pull' for valid url syntax"));

  /*
   * null-terminate hostname and point path to ~ for URL's like this:
   *    ssh://host.xz/~user/repo
   */

  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++;
  }

  path = xstrdup(path);
  *end = '\0';

  *ret_host = xstrdup(host);
  *ret_path = path;
  free(url);
  return protocol;
}

static const char *get_ssh_command(void)
{
  const char *ssh;

  if ((ssh = getenv("GIT_SSH_COMMAND")))
    return ssh;

  if (!git_config_get_string_tmp("core.sshcommand", &ssh))
    return ssh;

  return NULL;
}

enum ssh_variant {
  VARIANT_AUTO,
  VARIANT_SIMPLE,
  VARIANT_SSH,
  VARIANT_PLINK,
  VARIANT_PUTTY,
  VARIANT_TORTOISEPLINK,
};

static void override_ssh_variant(enum ssh_variant *ssh_variant)
{
  const char *variant = getenv("GIT_SSH_VARIANT");

  if (!variant && git_config_get_string_tmp("ssh.variant", &variant))
    return;

  if (!strcmp(variant, "auto"))
    *ssh_variant = VARIANT_AUTO;
  else if (!strcmp(variant, "plink"))
    *ssh_variant = VARIANT_PLINK;
  else if (!strcmp(variant, "putty"))
    *ssh_variant = VARIANT_PUTTY;
  else if (!strcmp(variant, "tortoiseplink"))
    *ssh_variant = VARIANT_TORTOISEPLINK;
  else if (!strcmp(variant, "simple"))
    *ssh_variant = VARIANT_SIMPLE;
  else
    *ssh_variant = VARIANT_SSH;
}

static enum ssh_variant determine_ssh_variant(const char *ssh_command,
                int is_cmdline)
{
  enum ssh_variant ssh_variant = VARIANT_AUTO;
  const char *variant;
  char *p = NULL;

  override_ssh_variant(&ssh_variant);

  if (ssh_variant != VARIANT_AUTO)
    return ssh_variant;

  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 ssh_variant;
    }
  }

  if (!strcasecmp(variant, "ssh") ||
      !strcasecmp(variant, "ssh.exe"))
    ssh_variant = VARIANT_SSH;
  else if (!strcasecmp(variant, "plink") ||
     !strcasecmp(variant, "plink.exe"))
    ssh_variant = VARIANT_PLINK;
  else if (!strcasecmp(variant, "tortoiseplink") ||
     !strcasecmp(variant, "tortoiseplink.exe"))
    ssh_variant = VARIANT_TORTOISEPLINK;

  free(p);
  return ssh_variant;
}

/*
 * Open a connection using Git's native protocol.
 *
 * The caller is responsible for freeing hostandport, but this function may
 * modify it (for example, to truncate it to remove the port part).
 */
static struct child_process *git_connect_git(int fd[2], char *hostandport,
               const char *path, const char *prog,
               enum protocol_version version,
               int flags)
{
  struct child_process *conn;
  struct strbuf request = STRBUF_INIT;
  /*
   * 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 (strchr(target_host, '\n') || strchr(path, '\n'))
    die(_("newline is forbidden in git:// hosts and repo paths"));

  /*
   * These underlying connection commands die() if they
   * cannot connect.
   */
  if (git_use_proxy(hostandport))
    conn = git_proxy_connect(fd, hostandport);
  else
    conn = git_tcp_connect(fd, hostandport, flags);
  /*
   * Separate original protocol components prog and path
   * from extended host header with a NUL byte.
   *
   * Note: Do not add any other headers here!  Doing so
   * will cause older git-daemon servers to crash.
   */
  strbuf_addf(&request,
        "%s %s%chost=%s%c",
        prog, path, 0,
        target_host, 0);

  /* If using a new version put that stuff here after a second null byte */
  if (version > 0) {
    strbuf_addch(&request, '\0');
    strbuf_addf(&request, "version=%d%c",
          version, '\0');
  }

  packet_write(fd[1], request.buf, request.len);

  free(target_host);
  strbuf_release(&request);
  return conn;
}

/*
 * Append the appropriate environment variables to `env` and options to
 * `args` for running ssh in Git's SSH-tunneled transport.
 */
static void push_ssh_options(struct strvec *args, struct strvec *env,
           enum ssh_variant variant, const char *port,
           enum protocol_version version, int flags)
{
  if (variant == VARIANT_SSH &&
      version > 0) {
    strvec_push(args, "-o");
    strvec_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
    strvec_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
           version);
  }

  if (flags & CONNECT_IPV4) {
    switch (variant) {
    case VARIANT_AUTO:
      BUG("VARIANT_AUTO passed to push_ssh_options");
    case VARIANT_SIMPLE:
      die(_("ssh variant 'simple' does not support -4"));
    case VARIANT_SSH:
    case VARIANT_PLINK:
    case VARIANT_PUTTY:
    case VARIANT_TORTOISEPLINK:
      strvec_push(args, "-4");
    }
  } else if (flags & CONNECT_IPV6) {
    switch (variant) {
    case VARIANT_AUTO:
      BUG("VARIANT_AUTO passed to push_ssh_options");
    case VARIANT_SIMPLE:
      die(_("ssh variant 'simple' does not support -6"));
    case VARIANT_SSH:
    case VARIANT_PLINK:
    case VARIANT_PUTTY:
    case VARIANT_TORTOISEPLINK:
      strvec_push(args, "-6");
    }
  }

  if (variant == VARIANT_TORTOISEPLINK)
    strvec_push(args, "-batch");

  if (port) {
    switch (variant) {
    case VARIANT_AUTO:
      BUG("VARIANT_AUTO passed to push_ssh_options");
    case VARIANT_SIMPLE:
      die(_("ssh variant 'simple' does not support setting port"));
    case VARIANT_SSH:
      strvec_push(args, "-p");
      break;
    case VARIANT_PLINK:
    case VARIANT_PUTTY:
    case VARIANT_TORTOISEPLINK:
      strvec_push(args, "-P");
    }

    strvec_push(args, port);
  }
}

/* Prepare a child_process for use by Git's SSH-tunneled transport. */
static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
        const char *port, enum protocol_version version,
        int flags)
{
  const char *ssh;
  enum ssh_variant variant;

  if (looks_like_command_line_option(ssh_host))
    die(_("strange hostname '%s' blocked"), ssh_host);

  ssh = get_ssh_command();
  if (ssh) {
    variant = determine_ssh_variant(ssh, 1);
  } 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";
    variant = determine_ssh_variant(ssh, 0);
  }

  if (variant == VARIANT_AUTO) {
    struct child_process detect = CHILD_PROCESS_INIT;

    detect.use_shell = conn->use_shell;
    detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;

    strvec_push(&detect.args, ssh);
    strvec_push(&detect.args, "-G");
    push_ssh_options(&detect.args, &detect.env,
         VARIANT_SSH, port, version, flags);
    strvec_push(&detect.args, ssh_host);

    variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
  }

  strvec_push(&conn->args, ssh);
  push_ssh_options(&conn->args, &conn->env, variant, port, version,
       flags);
  strvec_push(&conn->args, ssh_host);
}

/*
 * This returns the dummy child_process `no_fork` 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 *name,
          const char *prog, int flags)
{
  char *hostandport, *path;
  struct child_process *conn;
  enum protocol protocol;
  enum protocol_version version = get_protocol_version_config();

  /*
   * NEEDSWORK: If we are trying to use protocol v2 and we are planning
   * to perform any operation that doesn't involve upload-pack (i.e., a
   * fetch, ls-remote, etc), then fallback to v0 since we don't know how
   * to do anything else (like push or remote archive) via v2.
   */
  if (version == protocol_v2 && strcmp("git-upload-pack", name))
    version = protocol_v0;

  /* Without this we cannot rely on waitpid() to tell
   * what happened to our children.
   */
  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) {
    conn = git_connect_git(fd, hostandport, path, prog, version, flags);
    conn->trace2_child_class = "transport/git";
  } else {
    struct strbuf cmd = STRBUF_INIT;
    const char *const *var;

    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);

    /* remove repo-local variables from the environment */
    for (var = local_repo_env; *var; var++)
      strvec_push(&conn->env, *var);

    conn->use_shell = 1;
    conn->in = conn->out = -1;
    if (protocol == PROTO_SSH) {
      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);
        strbuf_release(&cmd);
        return NULL;
      }
      conn->trace2_child_class = "transport/ssh";
      fill_ssh_args(conn, ssh_host, port, version, flags);
    } else {
      transport_check_allowed("file");
      conn->trace2_child_class = "transport/file";
      if (version > 0) {
        strvec_pushf(&conn->env,
               GIT_PROTOCOL_ENVIRONMENT "=version=%d",
               version);
      }
    }
    strvec_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;
}

int finish_connect(struct child_process *conn)
{
  int code;
  if (!conn || git_connection_is_socket(conn))
    return 0;

  code = finish_command(conn);
  free(conn);
  return code;
}

Coverage Report

Created: 2023-11-30 07:19