/src/git/builtin/update-ref.c

Source (jump to first uncovered line)
#include "builtin.h"
#include "config.h"
#include "gettext.h"
#include "hash.h"
#include "refs.h"
#include "object-name.h"
#include "parse-options.h"
#include "quote.h"
#include "repository.h"

static const char * const git_update_ref_usage[] = {
  N_("git update-ref [<options>] -d <refname> [<old-oid>]"),
  N_("git update-ref [<options>]    <refname> <new-oid> [<old-oid>]"),
  N_("git update-ref [<options>] --stdin [-z]"),
  NULL
};

static char line_termination = '\n';
static unsigned int update_flags;
static unsigned int default_flags;
static unsigned create_reflog_flag;
static const char *msg;

/*
 * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
 * and append the result to arg.  Return a pointer to the terminator.
 * Die if there is an error in how the argument is C-quoted.  This
 * function is only used if not -z.
 */
static const char *parse_arg(const char *next, struct strbuf *arg)
{
  if (*next == '"') {
    const char *orig = next;

    if (unquote_c_style(arg, next, &next))
      die("badly quoted argument: %s", orig);
    if (*next && !isspace(*next))
      die("unexpected character after quoted argument: %s", orig);
  } else {
    while (*next && !isspace(*next))
      strbuf_addch(arg, *next++);
  }

  return next;
}

/*
 * Parse the reference name immediately after "command SP".  If not
 * -z, then handle C-quoting.  Return a pointer to a newly allocated
 * string containing the name of the reference, or NULL if there was
 * an error.  Update *next to point at the character that terminates
 * the argument.  Die if C-quoting is malformed or the reference name
 * is invalid.
 */
static char *parse_refname(const char **next)
{
  struct strbuf ref = STRBUF_INIT;

  if (line_termination) {
    /* Without -z, use the next argument */
    *next = parse_arg(*next, &ref);
  } else {
    /* With -z, use everything up to the next NUL */
    strbuf_addstr(&ref, *next);
    *next += ref.len;
  }

  if (!ref.len) {
    strbuf_release(&ref);
    return NULL;
  }

  if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
    die("invalid ref format: %s", ref.buf);

  return strbuf_detach(&ref, NULL);
}

/*
 * Wrapper around parse_refname which skips the next delimiter.
 */
static char *parse_next_refname(const char **next)
{
  if (line_termination) {
    /* Without -z, consume SP and use next argument */
    if (!**next || **next == line_termination)
      return NULL;
    if (**next != ' ')
      die("expected SP but got: %s", *next);
  } else {
    /* With -z, read the next NUL-terminated line */
    if (**next)
      return NULL;
  }
  /* Skip the delimiter */
  (*next)++;

  return parse_refname(next);
}

/*
 * Wrapper around parse_arg which skips the next delimiter.
 */
static char *parse_next_arg(const char **next)
{
  struct strbuf arg = STRBUF_INIT;

  if (line_termination) {
    /* Without -z, consume SP and use next argument */
    if (!**next || **next == line_termination)
      return NULL;
    if (**next != ' ')
      die("expected SP but got: %s", *next);
  } else {
    /* With -z, read the next NUL-terminated line */
    if (**next)
      return NULL;
  }
  /* Skip the delimiter */
  (*next)++;

  if (line_termination) {
    /* Without -z, use the next argument */
    *next = parse_arg(*next, &arg);
  } else {
    /* With -z, use everything up to the next NUL */
    strbuf_addstr(&arg, *next);
    *next += arg.len;
  }

  if (arg.len)
    return strbuf_detach(&arg, NULL);

  strbuf_release(&arg);
  return NULL;
}

/*
 * The value being parsed is <old-oid> (as opposed to <new-oid>; the
 * difference affects which error messages are generated):
 */
#define PARSE_SHA1_OLD 0x01

/*
 * For backwards compatibility, accept an empty string for update's
 * <new-oid> in binary mode to be equivalent to specifying zeros.
 */
#define PARSE_SHA1_ALLOW_EMPTY 0x02

/*
 * Parse an argument separator followed by the next argument, if any.
 * If there is an argument, convert it to a SHA-1, write it to sha1,
 * set *next to point at the character terminating the argument, and
 * return 0.  If there is no argument at all (not even the empty
 * string), return 1 and leave *next unchanged.  If the value is
 * provided but cannot be converted to a SHA-1, die.  flags can
 * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
 */
static int parse_next_oid(const char **next, const char *end,
        struct object_id *oid,
        const char *command, const char *refname,
        int flags)
{
  struct strbuf arg = STRBUF_INIT;
  int ret = 0;

  if (*next == end)
    goto eof;

  if (line_termination) {
    /* Without -z, consume SP and use next argument */
    if (!**next || **next == line_termination)
      return 1;
    if (**next != ' ')
      die("%s %s: expected SP but got: %s",
          command, refname, *next);
    (*next)++;
    *next = parse_arg(*next, &arg);
    if (arg.len) {
      if (repo_get_oid(the_repository, arg.buf, oid))
        goto invalid;
    } else {
      /* Without -z, an empty value means all zeros: */
      oidclr(oid, the_repository->hash_algo);
    }
  } else {
    /* With -z, read the next NUL-terminated line */
    if (**next)
      die("%s %s: expected NUL but got: %s",
          command, refname, *next);
    (*next)++;
    if (*next == end)
      goto eof;
    strbuf_addstr(&arg, *next);
    *next += arg.len;

    if (arg.len) {
      if (repo_get_oid(the_repository, arg.buf, oid))
        goto invalid;
    } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
      /* With -z, treat an empty value as all zeros: */
      warning("%s %s: missing <new-oid>, treating as zero",
        command, refname);
      oidclr(oid, the_repository->hash_algo);
    } else {
      /*
       * With -z, an empty non-required value means
       * unspecified:
       */
      ret = 1;
    }
  }

  strbuf_release(&arg);

  return ret;

 invalid:
  die(flags & PARSE_SHA1_OLD ?
      "%s %s: invalid <old-oid>: %s" :
      "%s %s: invalid <new-oid>: %s",
      command, refname, arg.buf);

 eof:
  die(flags & PARSE_SHA1_OLD ?
      "%s %s: unexpected end of input when reading <old-oid>" :
      "%s %s: unexpected end of input when reading <new-oid>",
      command, refname);
}


/*
 * The following five parse_cmd_*() functions parse the corresponding
 * command.  In each case, next points at the character following the
 * command name and the following space.  They each return a pointer
 * to the character terminating the command, and die with an
 * explanatory message if there are any parsing problems.  All of
 * these functions handle either text or binary format input,
 * depending on how line_termination is set.
 */

static void parse_cmd_update(struct ref_transaction *transaction,
           const char *next, const char *end)
{
  struct strbuf err = STRBUF_INIT;
  char *refname;
  struct object_id new_oid, old_oid;
  int have_old;

  refname = parse_refname(&next);
  if (!refname)
    die("update: missing <ref>");

  if (parse_next_oid(&next, end, &new_oid, "update", refname,
         PARSE_SHA1_ALLOW_EMPTY))
    die("update %s: missing <new-oid>", refname);

  have_old = !parse_next_oid(&next, end, &old_oid, "update", refname,
           PARSE_SHA1_OLD);

  if (*next != line_termination)
    die("update %s: extra input: %s", refname, next);

  if (ref_transaction_update(transaction, refname,
           &new_oid, have_old ? &old_oid : NULL,
           NULL, NULL,
           update_flags | create_reflog_flag,
           msg, &err))
    die("%s", err.buf);

  update_flags = default_flags;
  free(refname);
  strbuf_release(&err);
}

static void parse_cmd_symref_update(struct ref_transaction *transaction,
            const char *next, const char *end UNUSED)
{
  char *refname, *new_target, *old_arg;
  char *old_target = NULL;
  struct strbuf err = STRBUF_INIT;
  struct object_id old_oid;
  int have_old_oid = 0;

  refname = parse_refname(&next);
  if (!refname)
    die("symref-update: missing <ref>");

  new_target = parse_next_refname(&next);
  if (!new_target)
    die("symref-update %s: missing <new-target>", refname);

  old_arg = parse_next_arg(&next);
  if (old_arg) {
    old_target = parse_next_arg(&next);
    if (!old_target)
      die("symref-update %s: expected old value", refname);

    if (!strcmp(old_arg, "oid")) {
      if (repo_get_oid(the_repository, old_target, &old_oid))
        die("symref-update %s: invalid oid: %s", refname, old_target);

      have_old_oid = 1;
    } else if (!strcmp(old_arg, "ref")) {
      if (check_refname_format(old_target, REFNAME_ALLOW_ONELEVEL))
        die("symref-update %s: invalid ref: %s", refname, old_target);
    } else {
      die("symref-update %s: invalid arg '%s' for old value", refname, old_arg);
    }
  }

  if (*next != line_termination)
    die("symref-update %s: extra input: %s", refname, next);

  if (ref_transaction_update(transaction, refname, NULL,
           have_old_oid ? &old_oid : NULL,
           new_target,
           have_old_oid ? NULL : old_target,
           update_flags | create_reflog_flag,
           msg, &err))
    die("%s", err.buf);

  update_flags = default_flags;
  free(refname);
  free(old_arg);
  free(old_target);
  free(new_target);
  strbuf_release(&err);
}

static void parse_cmd_create(struct ref_transaction *transaction,
           const char *next, const char *end)
{
  struct strbuf err = STRBUF_INIT;
  char *refname;
  struct object_id new_oid;

  refname = parse_refname(&next);
  if (!refname)
    die("create: missing <ref>");

  if (parse_next_oid(&next, end, &new_oid, "create", refname, 0))
    die("create %s: missing <new-oid>", refname);

  if (is_null_oid(&new_oid))
    die("create %s: zero <new-oid>", refname);

  if (*next != line_termination)
    die("create %s: extra input: %s", refname, next);

  if (ref_transaction_create(transaction, refname, &new_oid, NULL,
           update_flags | create_reflog_flag,
           msg, &err))
    die("%s", err.buf);

  update_flags = default_flags;
  free(refname);
  strbuf_release(&err);
}


static void parse_cmd_symref_create(struct ref_transaction *transaction,
            const char *next, const char *end UNUSED)
{
  struct strbuf err = STRBUF_INIT;
  char *refname, *new_target;

  refname = parse_refname(&next);
  if (!refname)
    die("symref-create: missing <ref>");

  new_target = parse_next_refname(&next);
  if (!new_target)
    die("symref-create %s: missing <new-target>", refname);

  if (*next != line_termination)
    die("symref-create %s: extra input: %s", refname, next);

  if (ref_transaction_create(transaction, refname, NULL, new_target,
           update_flags | create_reflog_flag,
           msg, &err))
    die("%s", err.buf);

  update_flags = default_flags;
  free(refname);
  free(new_target);
  strbuf_release(&err);
}

static void parse_cmd_delete(struct ref_transaction *transaction,
           const char *next, const char *end)
{
  struct strbuf err = STRBUF_INIT;
  char *refname;
  struct object_id old_oid;
  int have_old;

  refname = parse_refname(&next);
  if (!refname)
    die("delete: missing <ref>");

  if (parse_next_oid(&next, end, &old_oid, "delete", refname,
         PARSE_SHA1_OLD)) {
    have_old = 0;
  } else {
    if (is_null_oid(&old_oid))
      die("delete %s: zero <old-oid>", refname);
    have_old = 1;
  }

  if (*next != line_termination)
    die("delete %s: extra input: %s", refname, next);

  if (ref_transaction_delete(transaction, refname,
           have_old ? &old_oid : NULL,
           NULL, update_flags, msg, &err))
    die("%s", err.buf);

  update_flags = default_flags;
  free(refname);
  strbuf_release(&err);
}


static void parse_cmd_symref_delete(struct ref_transaction *transaction,
            const char *next, const char *end UNUSED)
{
  struct strbuf err = STRBUF_INIT;
  char *refname, *old_target;

  if (!(update_flags & REF_NO_DEREF))
    die("symref-delete: cannot operate with deref mode");

  refname = parse_refname(&next);
  if (!refname)
    die("symref-delete: missing <ref>");

  old_target = parse_next_refname(&next);

  if (*next != line_termination)
    die("symref-delete %s: extra input: %s", refname, next);

  if (ref_transaction_delete(transaction, refname, NULL,
           old_target, update_flags, msg, &err))
    die("%s", err.buf);

  update_flags = default_flags;
  free(refname);
  free(old_target);
  strbuf_release(&err);
}


static void parse_cmd_verify(struct ref_transaction *transaction,
           const char *next, const char *end)
{
  struct strbuf err = STRBUF_INIT;
  char *refname;
  struct object_id old_oid;

  refname = parse_refname(&next);
  if (!refname)
    die("verify: missing <ref>");

  if (parse_next_oid(&next, end, &old_oid, "verify", refname,
         PARSE_SHA1_OLD))
    oidclr(&old_oid, the_repository->hash_algo);

  if (*next != line_termination)
    die("verify %s: extra input: %s", refname, next);

  if (ref_transaction_verify(transaction, refname, &old_oid,
           NULL, update_flags, &err))
    die("%s", err.buf);

  update_flags = default_flags;
  free(refname);
  strbuf_release(&err);
}

static void parse_cmd_symref_verify(struct ref_transaction *transaction,
            const char *next, const char *end UNUSED)
{
  struct strbuf err = STRBUF_INIT;
  struct object_id old_oid;
  char *refname, *old_target;

  if (!(update_flags & REF_NO_DEREF))
    die("symref-verify: cannot operate with deref mode");

  refname = parse_refname(&next);
  if (!refname)
    die("symref-verify: missing <ref>");

  /*
   * old_ref is optional, if not provided, we need to ensure that the
   * ref doesn't exist.
   */
  old_target = parse_next_refname(&next);
  if (!old_target)
    oidcpy(&old_oid, null_oid());

  if (*next != line_termination)
    die("symref-verify %s: extra input: %s", refname, next);

  if (ref_transaction_verify(transaction, refname,
           old_target ? NULL : &old_oid,
           old_target, update_flags, &err))
    die("%s", err.buf);

  update_flags = default_flags;
  free(refname);
  free(old_target);
  strbuf_release(&err);
}

static void report_ok(const char *command)
{
  fprintf(stdout, "%s: ok\n", command);
  fflush(stdout);
}

static void parse_cmd_option(struct ref_transaction *transaction UNUSED,
           const char *next, const char *end UNUSED)
{
  const char *rest;
  if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
    update_flags |= REF_NO_DEREF;
  else
    die("option unknown: %s", next);
}

static void parse_cmd_start(struct ref_transaction *transaction UNUSED,
          const char *next, const char *end UNUSED)
{
  if (*next != line_termination)
    die("start: extra input: %s", next);
  report_ok("start");
}

static void parse_cmd_prepare(struct ref_transaction *transaction,
            const char *next, const char *end UNUSED)
{
  struct strbuf error = STRBUF_INIT;
  if (*next != line_termination)
    die("prepare: extra input: %s", next);
  if (ref_transaction_prepare(transaction, &error))
    die("prepare: %s", error.buf);
  report_ok("prepare");
}

static void parse_cmd_abort(struct ref_transaction *transaction,
          const char *next, const char *end UNUSED)
{
  struct strbuf error = STRBUF_INIT;
  if (*next != line_termination)
    die("abort: extra input: %s", next);
  if (ref_transaction_abort(transaction, &error))
    die("abort: %s", error.buf);
  report_ok("abort");
}

static void parse_cmd_commit(struct ref_transaction *transaction,
           const char *next, const char *end UNUSED)
{
  struct strbuf error = STRBUF_INIT;
  if (*next != line_termination)
    die("commit: extra input: %s", next);
  if (ref_transaction_commit(transaction, &error))
    die("commit: %s", error.buf);
  report_ok("commit");
  ref_transaction_free(transaction);
}

enum update_refs_state {
  /* Non-transactional state open for updates. */
  UPDATE_REFS_OPEN,
  /* A transaction has been started. */
  UPDATE_REFS_STARTED,
  /* References are locked and ready for commit */
  UPDATE_REFS_PREPARED,
  /* Transaction has been committed or closed. */
  UPDATE_REFS_CLOSED,
};

static const struct parse_cmd {
  const char *prefix;
  void (*fn)(struct ref_transaction *, const char *, const char *);
  unsigned args;
  enum update_refs_state state;
} command[] = {
  { "update",        parse_cmd_update,        3, UPDATE_REFS_OPEN },
  { "create",        parse_cmd_create,        2, UPDATE_REFS_OPEN },
  { "delete",        parse_cmd_delete,        2, UPDATE_REFS_OPEN },
  { "verify",        parse_cmd_verify,        2, UPDATE_REFS_OPEN },
  { "symref-update", parse_cmd_symref_update, 4, UPDATE_REFS_OPEN },
  { "symref-create", parse_cmd_symref_create, 2, UPDATE_REFS_OPEN },
  { "symref-delete", parse_cmd_symref_delete, 2, UPDATE_REFS_OPEN },
  { "symref-verify", parse_cmd_symref_verify, 2, UPDATE_REFS_OPEN },
  { "option",        parse_cmd_option,        1, UPDATE_REFS_OPEN },
  { "start",         parse_cmd_start,         0, UPDATE_REFS_STARTED },
  { "prepare",       parse_cmd_prepare,       0, UPDATE_REFS_PREPARED },
  { "abort",         parse_cmd_abort,         0, UPDATE_REFS_CLOSED },
  { "commit",        parse_cmd_commit,        0, UPDATE_REFS_CLOSED },
};

static void update_refs_stdin(void)
{
  struct strbuf input = STRBUF_INIT, err = STRBUF_INIT;
  enum update_refs_state state = UPDATE_REFS_OPEN;
  struct ref_transaction *transaction;
  int i, j;

  transaction = ref_store_transaction_begin(get_main_ref_store(the_repository),
              &err);
  if (!transaction)
    die("%s", err.buf);

  /* Read each line dispatch its command */
  while (!strbuf_getwholeline(&input, stdin, line_termination)) {
    const struct parse_cmd *cmd = NULL;

    if (*input.buf == line_termination)
      die("empty command in input");
    else if (isspace(*input.buf))
      die("whitespace before command: %s", input.buf);

    for (i = 0; i < ARRAY_SIZE(command); i++) {
      const char *prefix = command[i].prefix;
      char c;

      if (!starts_with(input.buf, prefix))
        continue;

      /*
       * If the command has arguments, verify that it's
       * followed by a space. Otherwise, it shall be followed
       * by a line terminator.
       */
      c = command[i].args ? ' ' : line_termination;
      if (input.buf[strlen(prefix)] != c)
        continue;

      cmd = &command[i];
      break;
    }
    if (!cmd)
      die("unknown command: %s", input.buf);

    /*
     * Read additional arguments if NUL-terminated. Do not raise an
     * error in case there is an early EOF to let the command
     * handle missing arguments with a proper error message.
     */
    for (j = 1; line_termination == '\0' && j < cmd->args; j++)
      if (strbuf_appendwholeline(&input, stdin, line_termination))
        break;

    switch (state) {
    case UPDATE_REFS_OPEN:
    case UPDATE_REFS_STARTED:
      if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
        die("cannot restart ongoing transaction");
      /* Do not downgrade a transaction to a non-transaction. */
      if (cmd->state >= state)
        state = cmd->state;
      break;
    case UPDATE_REFS_PREPARED:
      if (cmd->state != UPDATE_REFS_CLOSED)
        die("prepared transactions can only be closed");
      state = cmd->state;
      break;
    case UPDATE_REFS_CLOSED:
      if (cmd->state != UPDATE_REFS_STARTED)
        die("transaction is closed");

      /*
       * Open a new transaction if we're currently closed and
       * get a "start".
       */
      state = cmd->state;
      transaction = ref_store_transaction_begin(get_main_ref_store(the_repository),
                  &err);
      if (!transaction)
        die("%s", err.buf);

      break;
    }

    cmd->fn(transaction, input.buf + strlen(cmd->prefix) + !!cmd->args,
      input.buf + input.len);
  }

  switch (state) {
  case UPDATE_REFS_OPEN:
    /* Commit by default if no transaction was requested. */
    if (ref_transaction_commit(transaction, &err))
      die("%s", err.buf);
    ref_transaction_free(transaction);
    break;
  case UPDATE_REFS_STARTED:
  case UPDATE_REFS_PREPARED:
    /* If using a transaction, we want to abort it. */
    if (ref_transaction_abort(transaction, &err))
      die("%s", err.buf);
    break;
  case UPDATE_REFS_CLOSED:
    /* Otherwise no need to do anything, the transaction was closed already. */
    break;
  }

  strbuf_release(&err);
  strbuf_release(&input);
}

int cmd_update_ref(int argc, const char **argv, const char *prefix)
{
  const char *refname, *oldval;
  struct object_id oid, oldoid;
  int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
  int create_reflog = 0;
  struct option options[] = {
    OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
    OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
    OPT_BOOL( 0 , "no-deref", &no_deref,
          N_("update <refname> not the one it points to")),
    OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
    OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
    OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
    OPT_END(),
  };

  git_config(git_default_config, NULL);
  argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
           0);
  if (msg && !*msg)
    die("Refusing to perform update with empty message.");

  create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;

  if (no_deref) {
    default_flags = REF_NO_DEREF;
    update_flags = default_flags;
  }

  if (read_stdin) {
    if (delete || argc > 0)
      usage_with_options(git_update_ref_usage, options);
    if (end_null)
      line_termination = '\0';
    update_refs_stdin();
    return 0;
  }

  if (end_null)
    usage_with_options(git_update_ref_usage, options);

  if (delete) {
    if (argc < 1 || argc > 2)
      usage_with_options(git_update_ref_usage, options);
    refname = argv[0];
    oldval = argv[1];
  } else {
    const char *value;
    if (argc < 2 || argc > 3)
      usage_with_options(git_update_ref_usage, options);
    refname = argv[0];
    value = argv[1];
    oldval = argv[2];
    if (repo_get_oid(the_repository, value, &oid))
      die("%s: not a valid SHA1", value);
  }

  if (oldval) {
    if (!*oldval)
      /*
       * The empty string implies that the reference
       * must not already exist:
       */
      oidclr(&oldoid, the_repository->hash_algo);
    else if (repo_get_oid(the_repository, oldval, &oldoid))
      die("%s: not a valid old SHA1", oldval);
  }

  if (delete)
    /*
     * For purposes of backwards compatibility, we treat
     * NULL_SHA1 as "don't care" here:
     */
    return refs_delete_ref(get_main_ref_store(the_repository),
               msg, refname,
               (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
               default_flags);
  else
    return refs_update_ref(get_main_ref_store(the_repository),
               msg, refname, &oid,
               oldval ? &oldoid : NULL,
               default_flags | create_reflog_flag,
               UPDATE_REFS_DIE_ON_ERR);
}

Coverage Report

Created: 2024-09-08 06:23