/src/libgit2/src/libgit2/config_file.c

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/*
 * Copyright (C) the libgit2 contributors. All rights reserved.
 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */

#include "config.h"

#include "git2/config.h"
#include "git2/sys/config.h"

#include "array.h"
#include "str.h"
#include "config_backend.h"
#include "config_list.h"
#include "config_parse.h"
#include "filebuf.h"
#include "regexp.h"
#include "sysdir.h"
#include "wildmatch.h"
#include "hash.h"

/* Max depth for [include] directives */
#define MAX_INCLUDE_DEPTH 10

#define CONFIG_FILE_TYPE "file"

typedef struct config_file {
  git_futils_filestamp stamp;
  unsigned char checksum[GIT_HASH_SHA256_SIZE];
  char *path;
  git_array_t(struct config_file) includes;
} config_file;

typedef struct {
  git_config_backend parent;
  git_mutex values_mutex;
  git_config_list *config_list;
  const git_repository *repo;
  git_config_level_t level;

  git_array_t(git_config_parser) readers;

  bool locked;
  git_filebuf locked_buf;
  git_str locked_content;

  config_file file;
} config_file_backend;

typedef struct {
  const git_repository *repo;
  config_file *file;
  git_config_list *config_list;
  git_config_level_t level;
  unsigned int depth;
} config_file_parse_data;

static int config_file_read(git_config_list *config_list, const git_repository *repo, config_file *file, git_config_level_t level, int depth);
static int config_file_read_buffer(git_config_list *config_list, const git_repository *repo, config_file *file, git_config_level_t level, int depth, const char *buf, size_t buflen);
static int config_file_write(config_file_backend *cfg, const char *orig_key, const char *key, const git_regexp *preg, const char *value);
static char *escape_value(const char *ptr);

/**
 * Take the current values map from the backend and increase its
 * refcount. This is its own function to make sure we use the mutex to
 * avoid the map pointer from changing under us.
 */
static int config_file_take_list(git_config_list **out, config_file_backend *b)
{
  int error;

  if ((error = git_mutex_lock(&b->values_mutex)) < 0) {
    git_error_set(GIT_ERROR_OS, "failed to lock config backend");
    return error;
  }

  git_config_list_incref(b->config_list);
  *out = b->config_list;

  git_mutex_unlock(&b->values_mutex);

  return 0;
}

static void config_file_clear(config_file *file)
{
  config_file *include;
  uint32_t i;

  if (file == NULL)
    return;

  git_array_foreach(file->includes, i, include) {
    config_file_clear(include);
  }
  git_array_clear(file->includes);

  git__free(file->path);
}

static int config_file_open(git_config_backend *cfg, git_config_level_t level, const git_repository *repo)
{
  config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  int res;

  b->level = level;
  b->repo = repo;

  if ((res = git_config_list_new(&b->config_list)) < 0)
    return res;

  if (!git_fs_path_exists(b->file.path))
    return 0;

  /*
   * git silently ignores configuration files that are not
   * readable.  We emulate that behavior.  This is particularly
   * important for sandboxed applications on macOS where the
   * git configuration files may not be readable.
   */
  if (p_access(b->file.path, R_OK) < 0)
    return GIT_ENOTFOUND;

  if (res < 0 || (res = config_file_read(b->config_list, repo, &b->file, level, 0)) < 0) {
    git_config_list_free(b->config_list);
    b->config_list = NULL;
  }

  return res;
}

static int config_file_is_modified(int *modified, config_file *file)
{
  config_file *include;
  git_str buf = GIT_STR_INIT;
  unsigned char checksum[GIT_HASH_SHA256_SIZE];
  uint32_t i;
  int error = 0;

  *modified = 0;

  if (!git_futils_filestamp_check(&file->stamp, file->path))
    goto check_includes;

  if ((error = git_futils_readbuffer(&buf, file->path)) < 0)
    goto out;

  if ((error = git_hash_buf(checksum, buf.ptr, buf.size, GIT_HASH_ALGORITHM_SHA256)) < 0)
    goto out;

  if (memcmp(checksum, file->checksum, GIT_HASH_SHA256_SIZE) != 0) {
    *modified = 1;
    goto out;
  }

check_includes:
  git_array_foreach(file->includes, i, include) {
    if ((error = config_file_is_modified(modified, include)) < 0 || *modified)
      goto out;
  }

out:
  git_str_dispose(&buf);

  return error;
}

static void config_file_clear_includes(config_file_backend *cfg)
{
  config_file *include;
  uint32_t i;

  git_array_foreach(cfg->file.includes, i, include)
    config_file_clear(include);
  git_array_clear(cfg->file.includes);
}

static int config_file_set_entries(git_config_backend *cfg, git_config_list *config_list)
{
  config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  git_config_list *old = NULL;
  int error;

  if (b->parent.readonly) {
    git_error_set(GIT_ERROR_CONFIG, "this backend is read-only");
    return -1;
  }

  if ((error = git_mutex_lock(&b->values_mutex)) < 0) {
    git_error_set(GIT_ERROR_OS, "failed to lock config backend");
    goto out;
  }

  old = b->config_list;
  b->config_list = config_list;

  git_mutex_unlock(&b->values_mutex);

out:
  git_config_list_free(old);
  return error;
}

static int config_file_refresh_from_buffer(git_config_backend *cfg, const char *buf, size_t buflen)
{
  config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  git_config_list *config_list = NULL;
  int error;

  config_file_clear_includes(b);

  if ((error = git_config_list_new(&config_list)) < 0 ||
      (error = config_file_read_buffer(config_list, b->repo, &b->file,
               b->level, 0, buf, buflen)) < 0 ||
      (error = config_file_set_entries(cfg, config_list)) < 0)
    goto out;

  config_list = NULL;
out:
  git_config_list_free(config_list);
  return error;
}

static int config_file_refresh(git_config_backend *cfg)
{
  config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  git_config_list *config_list = NULL;
  int error, modified;

  if (cfg->readonly)
    return 0;

  if ((error = config_file_is_modified(&modified, &b->file)) < 0 && error != GIT_ENOTFOUND)
    goto out;

  if (!modified)
    return 0;

  config_file_clear_includes(b);

  if ((error = git_config_list_new(&config_list)) < 0 ||
      (error = config_file_read(config_list, b->repo, &b->file, b->level, 0)) < 0 ||
      (error = config_file_set_entries(cfg, config_list)) < 0)
    goto out;

  config_list = NULL;
out:
  git_config_list_free(config_list);

  return (error == GIT_ENOTFOUND) ? 0 : error;
}

static void config_file_free(git_config_backend *_backend)
{
  config_file_backend *backend = GIT_CONTAINER_OF(_backend, config_file_backend, parent);

  if (backend == NULL)
    return;

  config_file_clear(&backend->file);
  git_config_list_free(backend->config_list);
  git_mutex_free(&backend->values_mutex);
  git__free(backend);
}

static int config_file_iterator(
  git_config_iterator **iter,
  struct git_config_backend *backend)
{
  config_file_backend *b = GIT_CONTAINER_OF(backend, config_file_backend, parent);
  git_config_list *dupped = NULL, *config_list = NULL;
  int error;

  if ((error = config_file_refresh(backend)) < 0 ||
      (error = config_file_take_list(&config_list, b)) < 0 ||
      (error = git_config_list_dup(&dupped, config_list)) < 0 ||
      (error = git_config_list_iterator_new(iter, dupped)) < 0)
    goto out;

out:
  /* Let iterator delete duplicated config_list when it's done */
  git_config_list_free(config_list);
  git_config_list_free(dupped);
  return error;
}

static int config_file_snapshot(git_config_backend **out, git_config_backend *backend)
{
  return git_config_backend_snapshot(out, backend);
}

static int config_file_set(git_config_backend *cfg, const char *name, const char *value)
{
  config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  git_config_list *config_list;
  git_config_list_entry *existing;
  char *key, *esc_value = NULL;
  int error;

  if ((error = git_config__normalize_name(name, &key)) < 0)
    return error;

  if ((error = config_file_take_list(&config_list, b)) < 0)
    return error;

  /* Check whether we'd be modifying an included or multivar key */
  if ((error = git_config_list_get_unique(&existing, config_list, key)) < 0) {
    if (error != GIT_ENOTFOUND)
      goto out;
    error = 0;
  } else if ((!existing->base.value && !value) ||
       (existing->base.value && value && !strcmp(existing->base.value, value))) {
    /* don't update if old and new values already match */
    error = 0;
    goto out;
  }

  /* No early returns due to sanity checks, let's write it out and refresh */
  if (value) {
    esc_value = escape_value(value);
    GIT_ERROR_CHECK_ALLOC(esc_value);
  }

  if ((error = config_file_write(b, name, key, NULL, esc_value)) < 0)
    goto out;

out:
  git_config_list_free(config_list);
  git__free(esc_value);
  git__free(key);
  return error;
}

/*
 * Internal function that actually gets the value in string form
 */
static int config_file_get(git_config_backend *cfg, const char *key, git_config_entry **out)
{
  config_file_backend *h = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  git_config_list *config_list = NULL;
  git_config_list_entry *entry;
  int error = 0;

  if (!h->parent.readonly && ((error = config_file_refresh(cfg)) < 0))
    return error;

  if ((error = config_file_take_list(&config_list, h)) < 0)
    return error;

  if ((error = (git_config_list_get(&entry, config_list, key))) < 0) {
    git_config_list_free(config_list);
    return error;
  }

  *out = &entry->base;

  return 0;
}

static int config_file_set_multivar(
  git_config_backend *cfg, const char *name, const char *regexp, const char *value)
{
  config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  git_regexp preg;
  int result;
  char *key;

  GIT_ASSERT_ARG(regexp);

  if ((result = git_config__normalize_name(name, &key)) < 0)
    return result;

  if ((result = git_regexp_compile(&preg, regexp, 0)) < 0)
    goto out;

  /* If we do have it, set call config_file_write() and reload */
  if ((result = config_file_write(b, name, key, &preg, value)) < 0)
    goto out;

out:
  git__free(key);
  git_regexp_dispose(&preg);

  return result;
}

static int config_file_delete(git_config_backend *cfg, const char *name)
{
  config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  git_config_list *config_list = NULL;
  git_config_list_entry *entry;
  char *key = NULL;
  int error;

  if ((error = git_config__normalize_name(name, &key)) < 0)
    goto out;

  if ((error = config_file_take_list(&config_list, b)) < 0)
    goto out;

  /* Check whether we'd be modifying an included or multivar key */
  if ((error = git_config_list_get_unique(&entry, config_list, key)) < 0) {
    if (error == GIT_ENOTFOUND)
      git_error_set(GIT_ERROR_CONFIG, "could not find key '%s' to delete", name);
    goto out;
  }

  if ((error = config_file_write(b, name, entry->base.name, NULL, NULL)) < 0)
    goto out;

out:
  git_config_list_free(config_list);
  git__free(key);
  return error;
}

static int config_file_delete_multivar(git_config_backend *cfg, const char *name, const char *regexp)
{
  config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
  git_config_list *config_list = NULL;
  git_config_list_entry *entry = NULL;
  git_regexp preg = GIT_REGEX_INIT;
  char *key = NULL;
  int result;

  if ((result = git_config__normalize_name(name, &key)) < 0)
    goto out;

  if ((result = config_file_take_list(&config_list, b)) < 0)
    goto out;

  if ((result = git_config_list_get(&entry, config_list, key)) < 0) {
    if (result == GIT_ENOTFOUND)
      git_error_set(GIT_ERROR_CONFIG, "could not find key '%s' to delete", name);
    goto out;
  }

  if ((result = git_regexp_compile(&preg, regexp, 0)) < 0)
    goto out;

  if ((result = config_file_write(b, name, key, &preg, NULL)) < 0)
    goto out;

out:
  git_config_list_free(config_list);
  git__free(key);
  git_regexp_dispose(&preg);
  return result;
}

static int config_file_lock(git_config_backend *_cfg)
{
  config_file_backend *cfg = GIT_CONTAINER_OF(_cfg, config_file_backend, parent);
  int error;

  if ((error = git_filebuf_open(&cfg->locked_buf, cfg->file.path, 0, GIT_CONFIG_FILE_MODE)) < 0)
    return error;

  error = git_futils_readbuffer(&cfg->locked_content, cfg->file.path);
  if (error < 0 && error != GIT_ENOTFOUND) {
    git_filebuf_cleanup(&cfg->locked_buf);
    return error;
  }

  cfg->locked = true;
  return 0;

}

static int config_file_unlock(git_config_backend *_cfg, int success)
{
  config_file_backend *cfg = GIT_CONTAINER_OF(_cfg, config_file_backend, parent);
  int error = 0;

  if (success) {
    git_filebuf_write(&cfg->locked_buf, cfg->locked_content.ptr, cfg->locked_content.size);
    error = git_filebuf_commit(&cfg->locked_buf);
  }

  git_filebuf_cleanup(&cfg->locked_buf);
  git_str_dispose(&cfg->locked_content);
  cfg->locked = false;

  return error;
}

int git_config_backend_from_file(git_config_backend **out, const char *path)
{
  config_file_backend *backend;

  backend = git__calloc(1, sizeof(config_file_backend));
  GIT_ERROR_CHECK_ALLOC(backend);

  backend->parent.version = GIT_CONFIG_BACKEND_VERSION;
  git_mutex_init(&backend->values_mutex);

  backend->file.path = git__strdup(path);
  GIT_ERROR_CHECK_ALLOC(backend->file.path);
  git_array_init(backend->file.includes);

  backend->parent.open = config_file_open;
  backend->parent.get = config_file_get;
  backend->parent.set = config_file_set;
  backend->parent.set_multivar = config_file_set_multivar;
  backend->parent.del = config_file_delete;
  backend->parent.del_multivar = config_file_delete_multivar;
  backend->parent.iterator = config_file_iterator;
  backend->parent.snapshot = config_file_snapshot;
  backend->parent.lock = config_file_lock;
  backend->parent.unlock = config_file_unlock;
  backend->parent.free = config_file_free;

  *out = (git_config_backend *)backend;

  return 0;
}

static int included_path(git_str *out, const char *dir, const char *path)
{
  /* From the user's home */
  if (path[0] == '~' && path[1] == '/')
    return git_sysdir_expand_homedir_file(out, &path[1]);

  return git_fs_path_join_unrooted(out, path, dir, NULL);
}

/* Escape the values to write them to the file */
static char *escape_value(const char *ptr)
{
  git_str buf;
  size_t len;
  const char *esc;

  GIT_ASSERT_ARG_WITH_RETVAL(ptr, NULL);

  len = strlen(ptr);
  if (!len)
    return git__calloc(1, sizeof(char));

  if (git_str_init(&buf, len) < 0)
    return NULL;

  while (*ptr != '\0') {
    if ((esc = strchr(git_config_escaped, *ptr)) != NULL) {
      git_str_putc(&buf, '\\');
      git_str_putc(&buf, git_config_escapes[esc - git_config_escaped]);
    } else {
      git_str_putc(&buf, *ptr);
    }
    ptr++;
  }

  if (git_str_oom(&buf))
    return NULL;

  return git_str_detach(&buf);
}

static int parse_include(config_file_parse_data *parse_data, const char *file)
{
  config_file *include;
  git_str path = GIT_STR_INIT;
  char *dir;
  int result;

  if (!file)
    return 0;

  if ((result = git_fs_path_dirname_r(&path, parse_data->file->path)) < 0)
    return result;

  dir = git_str_detach(&path);
  result = included_path(&path, dir, file);
  git__free(dir);

  if (result < 0)
    return result;

  include = git_array_alloc(parse_data->file->includes);
  GIT_ERROR_CHECK_ALLOC(include);
  memset(include, 0, sizeof(*include));
  git_array_init(include->includes);
  include->path = git_str_detach(&path);

  result = config_file_read(parse_data->config_list, parse_data->repo, include,
          parse_data->level, parse_data->depth+1);

  if (result == GIT_ENOTFOUND) {
    git_error_clear();
    result = 0;
  }

  return result;
}

static int do_match_gitdir(
  int *matches,
  const git_repository *repo,
  const char *cfg_file,
  const char *condition,
  bool case_insensitive)
{
  git_str pattern = GIT_STR_INIT, gitdir = GIT_STR_INIT;
  int error;

  if (condition[0] == '.' && git_fs_path_is_dirsep(condition[1])) {
    git_fs_path_dirname_r(&pattern, cfg_file);
    git_str_joinpath(&pattern, pattern.ptr, condition + 2);
  } else if (condition[0] == '~' && git_fs_path_is_dirsep(condition[1]))
    git_sysdir_expand_homedir_file(&pattern, condition + 1);
  else if (!git_fs_path_is_absolute(condition))
    git_str_joinpath(&pattern, "**", condition);
  else
    git_str_sets(&pattern, condition);

  if (git_fs_path_is_dirsep(condition[strlen(condition) - 1]))
    git_str_puts(&pattern, "**");

  if (git_str_oom(&pattern)) {
    error = -1;
    goto out;
  }

  if ((error = git_repository__item_path(&gitdir, repo, GIT_REPOSITORY_ITEM_GITDIR)) < 0)
    goto out;

  if (git_fs_path_is_dirsep(gitdir.ptr[gitdir.size - 1]))
    git_str_truncate(&gitdir, gitdir.size - 1);

  *matches = wildmatch(pattern.ptr, gitdir.ptr,
           WM_PATHNAME | (case_insensitive ? WM_CASEFOLD : 0)) == WM_MATCH;
out:
  git_str_dispose(&pattern);
  git_str_dispose(&gitdir);
  return error;
}

static int conditional_match_gitdir(
  int *matches,
  const git_repository *repo,
  const char *cfg_file,
  const char *value)
{
  return do_match_gitdir(matches, repo, cfg_file, value, false);
}

static int conditional_match_gitdir_i(
  int *matches,
  const git_repository *repo,
  const char *cfg_file,
  const char *value)
{
  return do_match_gitdir(matches, repo, cfg_file, value, true);
}

static int conditional_match_onbranch(
  int *matches,
  const git_repository *repo,
  const char *cfg_file,
  const char *condition)
{
  git_str reference = GIT_STR_INIT, buf = GIT_STR_INIT;
  int error;

  GIT_UNUSED(cfg_file);

  /*
   * NOTE: you cannot use `git_repository_head` here. Looking up the
   * HEAD reference will create the ODB, which causes us to read the
   * repo's config for keys like core.precomposeUnicode. As we're
   * just parsing the config right now, though, this would result in
   * an endless recursion.
   */

  if ((error = git_str_joinpath(&buf, git_repository_path(repo), GIT_HEAD_FILE)) < 0 ||
      (error = git_futils_readbuffer(&reference, buf.ptr)) < 0)
    goto out;
  git_str_rtrim(&reference);

  if (git__strncmp(reference.ptr, GIT_SYMREF, strlen(GIT_SYMREF)))
    goto out;
  git_str_consume(&reference, reference.ptr + strlen(GIT_SYMREF));

  if (git__strncmp(reference.ptr, GIT_REFS_HEADS_DIR, strlen(GIT_REFS_HEADS_DIR)))
    goto out;
  git_str_consume(&reference, reference.ptr + strlen(GIT_REFS_HEADS_DIR));

  /*
   * If the condition ends with a '/', then we should treat it as if
   * it had '**' appended.
   */
  if ((error = git_str_sets(&buf, condition)) < 0)
    goto out;
  if (git_fs_path_is_dirsep(condition[strlen(condition) - 1]) &&
      (error = git_str_puts(&buf, "**")) < 0)
    goto out;

  *matches = wildmatch(buf.ptr, reference.ptr, WM_PATHNAME) == WM_MATCH;
out:
  git_str_dispose(&reference);
  git_str_dispose(&buf);

  return error;

}

static const struct {
  const char *prefix;
  int (*matches)(int *matches, const git_repository *repo, const char *cfg, const char *value);
} conditions[] = {
  { "gitdir:", conditional_match_gitdir },
  { "gitdir/i:", conditional_match_gitdir_i },
  { "onbranch:", conditional_match_onbranch }
};

static int parse_conditional_include(config_file_parse_data *parse_data, const char *section, const char *file)
{
  char *condition;
  size_t section_len, i;
  int error = 0, matches;

  if (!parse_data->repo || !file)
    return 0;

  section_len = strlen(section);

  /*
   * We checked that the string starts with `includeIf.` and ends
   * in `.path` to get here.  Make sure it consists of more.
   */
  if (section_len < CONST_STRLEN("includeIf.") + CONST_STRLEN(".path"))
    return 0;

  condition = git__substrdup(section + CONST_STRLEN("includeIf."),
    section_len - CONST_STRLEN("includeIf.") - CONST_STRLEN(".path"));

  GIT_ERROR_CHECK_ALLOC(condition);

  for (i = 0; i < ARRAY_SIZE(conditions); i++) {
    if (git__prefixcmp(condition, conditions[i].prefix))
      continue;

    if ((error = conditions[i].matches(&matches,
               parse_data->repo,
               parse_data->file->path,
               condition + strlen(conditions[i].prefix))) < 0)
      break;

    if (matches)
      error = parse_include(parse_data, file);

    break;
  }

  git__free(condition);
  return error;
}

static int read_on_variable(
  git_config_parser *reader,
  const char *current_section,
  const char *var_name,
  const char *var_value,
  const char *line,
  size_t line_len,
  void *data)
{
  config_file_parse_data *parse_data = (config_file_parse_data *)data;
  git_str buf = GIT_STR_INIT;
  git_config_list_entry *entry;
  const char *c;
  int result = 0;

  GIT_UNUSED(reader);
  GIT_UNUSED(line);
  GIT_UNUSED(line_len);

  if (current_section) {
    /* TODO: Once warnings lang, we should likely warn
     * here. Git appears to warn in most cases if it sees
     * un-namespaced config options.
     */
    git_str_puts(&buf, current_section);
    git_str_putc(&buf, '.');
  }

  for (c = var_name; *c; c++)
    git_str_putc(&buf, git__tolower(*c));

  if (git_str_oom(&buf))
    return -1;

  entry = git__calloc(1, sizeof(git_config_list_entry));
  GIT_ERROR_CHECK_ALLOC(entry);

  entry->base.name = git_str_detach(&buf);
  GIT_ERROR_CHECK_ALLOC(entry->base.name);

  if (var_value) {
    entry->base.value = git__strdup(var_value);
    GIT_ERROR_CHECK_ALLOC(entry->base.value);
  }

  entry->base.backend_type = git_config_list_add_string(parse_data->config_list, CONFIG_FILE_TYPE);
  GIT_ERROR_CHECK_ALLOC(entry->base.backend_type);

  entry->base.origin_path = git_config_list_add_string(parse_data->config_list, parse_data->file->path);
  GIT_ERROR_CHECK_ALLOC(entry->base.origin_path);

  entry->base.level = parse_data->level;
  entry->base.include_depth = parse_data->depth;
  entry->base.free = git_config_list_entry_free;
  entry->config_list = parse_data->config_list;

  if ((result = git_config_list_append(parse_data->config_list, entry)) < 0)
    return result;

  result = 0;

  /* Add or append the new config option */
  if (!git__strcmp(entry->base.name, "include.path"))
    result = parse_include(parse_data, entry->base.value);
  else if (!git__prefixcmp(entry->base.name, "includeif.") &&
           !git__suffixcmp(entry->base.name, ".path"))
    result = parse_conditional_include(parse_data, entry->base.name, entry->base.value);

  return result;
}

static int config_file_read_buffer(
  git_config_list *config_list,
  const git_repository *repo,
  config_file *file,
  git_config_level_t level,
  int depth,
  const char *buf,
  size_t buflen)
{
  config_file_parse_data parse_data;
  git_config_parser reader;
  int error;

  if (depth >= MAX_INCLUDE_DEPTH) {
    git_error_set(GIT_ERROR_CONFIG, "maximum config include depth reached");
    return -1;
  }

  /* Initialize the reading position */
  reader.path = file->path;
  git_parse_ctx_init(&reader.ctx, buf, buflen);

  /* If the file is empty, there's nothing for us to do */
  if (!reader.ctx.content || *reader.ctx.content == '\0') {
    error = 0;
    goto out;
  }

  parse_data.repo = repo;
  parse_data.file = file;
  parse_data.config_list = config_list;
  parse_data.level = level;
  parse_data.depth = depth;

  error = git_config_parse(&reader, NULL, read_on_variable, NULL, NULL, &parse_data);

out:
  return error;
}

static int config_file_read(
  git_config_list *config_list,
  const git_repository *repo,
  config_file *file,
  git_config_level_t level,
  int depth)
{
  git_str contents = GIT_STR_INIT;
  struct stat st;
  int error;

  if (p_stat(file->path, &st) < 0) {
    error = git_fs_path_set_error(errno, file->path, "stat");
    goto out;
  }

  if ((error = git_futils_readbuffer(&contents, file->path)) < 0)
    goto out;

  git_futils_filestamp_set_from_stat(&file->stamp, &st);
  if ((error = git_hash_buf(file->checksum, contents.ptr, contents.size, GIT_HASH_ALGORITHM_SHA256)) < 0)
    goto out;

  if ((error = config_file_read_buffer(config_list, repo, file, level, depth,
               contents.ptr, contents.size)) < 0)
    goto out;

out:
  git_str_dispose(&contents);
  return error;
}

static int write_section(git_str *fbuf, const char *key)
{
  int result;
  const char *dot;
  git_str buf = GIT_STR_INIT;

  /* All of this just for [section "subsection"] */
  dot = strchr(key, '.');
  git_str_putc(&buf, '[');
  if (dot == NULL) {
    git_str_puts(&buf, key);
  } else {
    char *escaped;
    git_str_put(&buf, key, dot - key);
    escaped = escape_value(dot + 1);
    GIT_ERROR_CHECK_ALLOC(escaped);
    git_str_printf(&buf, " \"%s\"", escaped);
    git__free(escaped);
  }
  git_str_puts(&buf, "]\n");

  if (git_str_oom(&buf))
    return -1;

  result = git_str_put(fbuf, git_str_cstr(&buf), buf.size);
  git_str_dispose(&buf);

  return result;
}

static const char *quotes_for_value(const char *value)
{
  const char *ptr;

  if (value[0] == ' ' || value[0] == '\0')
    return "\"";

  for (ptr = value; *ptr; ++ptr) {
    if (*ptr == ';' || *ptr == '#')
      return "\"";
  }

  if (ptr[-1] == ' ')
    return "\"";

  return "";
}

struct write_data {
  git_str *buf;
  git_str buffered_comment;
  unsigned int in_section : 1,
    preg_replaced : 1;
  const char *orig_section;
  const char *section;
  const char *orig_name;
  const char *name;
  const git_regexp *preg;
  const char *value;
};

static int write_line_to(git_str *buf, const char *line, size_t line_len)
{
  int result = git_str_put(buf, line, line_len);

  if (!result && line_len && line[line_len-1] != '\n')
    result = git_str_printf(buf, "\n");

  return result;
}

static int write_line(struct write_data *write_data, const char *line, size_t line_len)
{
  return write_line_to(write_data->buf, line, line_len);
}

static int write_value(struct write_data *write_data)
{
  const char *q;
  int result;

  q = quotes_for_value(write_data->value);
  result = git_str_printf(write_data->buf,
    "\t%s = %s%s%s\n", write_data->orig_name, q, write_data->value, q);

  /* If we are updating a single name/value, we're done.  Setting `value`
   * to `NULL` will prevent us from trying to write it again later (in
   * `write_on_section`) if we see the same section repeated.
   */
  if (!write_data->preg)
    write_data->value = NULL;

  return result;
}

static int write_on_section(
  git_config_parser *reader,
  const char *current_section,
  const char *line,
  size_t line_len,
  void *data)
{
  struct write_data *write_data = (struct write_data *)data;
  int result = 0;

  GIT_UNUSED(reader);

  /* If we were previously in the correct section (but aren't anymore)
   * and haven't written our value (for a simple name/value set, not
   * a multivar), then append it to the end of the section before writing
   * the new one.
   */
  if (write_data->in_section && !write_data->preg && write_data->value)
    result = write_value(write_data);

  write_data->in_section = strcmp(current_section, write_data->section) == 0;

  /*
   * If there were comments just before this section, dump them as well.
   */
  if (!result) {
    result = git_str_put(write_data->buf, write_data->buffered_comment.ptr, write_data->buffered_comment.size);
    git_str_clear(&write_data->buffered_comment);
  }

  if (!result)
    result = write_line(write_data, line, line_len);

  return result;
}

static int write_on_variable(
  git_config_parser *reader,
  const char *current_section,
  const char *var_name,
  const char *var_value,
  const char *line,
  size_t line_len,
  void *data)
{
  struct write_data *write_data = (struct write_data *)data;
  bool has_matched = false;
  int error;

  GIT_UNUSED(reader);
  GIT_UNUSED(current_section);

  /*
   * If there were comments just before this variable, let's dump them as well.
   */
  if ((error = git_str_put(write_data->buf, write_data->buffered_comment.ptr, write_data->buffered_comment.size)) < 0)
    return error;

  git_str_clear(&write_data->buffered_comment);

  /* See if we are to update this name/value pair; first examine name */
  if (write_data->in_section &&
    strcasecmp(write_data->name, var_name) == 0)
    has_matched = true;

  /* If we have a regex to match the value, see if it matches */
  if (has_matched && write_data->preg != NULL)
    has_matched = (git_regexp_match(write_data->preg, var_value) == 0);

  /* If this isn't the name/value we're looking for, simply dump the
   * existing data back out and continue on.
   */
  if (!has_matched)
    return write_line(write_data, line, line_len);

  write_data->preg_replaced = 1;

  /* If value is NULL, we are deleting this value; write nothing. */
  if (!write_data->value)
    return 0;

  return write_value(write_data);
}

static int write_on_comment(git_config_parser *reader, const char *line, size_t line_len, void *data)
{
  struct write_data *write_data;

  GIT_UNUSED(reader);

  write_data = (struct write_data *)data;
  return write_line_to(&write_data->buffered_comment, line, line_len);
}

static int write_on_eof(
  git_config_parser *reader, const char *current_section, void *data)
{
  struct write_data *write_data = (struct write_data *)data;
  int result = 0;

  GIT_UNUSED(reader);

  /*
   * If we've buffered comments when reaching EOF, make sure to dump them.
   */
  if ((result = git_str_put(write_data->buf, write_data->buffered_comment.ptr, write_data->buffered_comment.size)) < 0)
    return result;

  /* If we are at the EOF and have not written our value (again, for a
   * simple name/value set, not a multivar) then we have never seen the
   * section in question and should create a new section and write the
   * value.
   */
  if ((!write_data->preg || !write_data->preg_replaced) && write_data->value) {
    /* write the section header unless we're already in it */
    if (!current_section || strcmp(current_section, write_data->section))
      result = write_section(write_data->buf, write_data->orig_section);

    if (!result)
      result = write_value(write_data);
  }

  return result;
}

/*
 * This is pretty much the parsing, except we write out anything we don't have
 */
static int config_file_write(
  config_file_backend *cfg,
  const char *orig_key,
  const char *key,
  const git_regexp *preg,
  const char *value)

{
  char *orig_section = NULL, *section = NULL, *orig_name, *name, *ldot;
  git_str buf = GIT_STR_INIT, contents = GIT_STR_INIT;
  git_config_parser parser = GIT_CONFIG_PARSER_INIT;
  git_filebuf file = GIT_FILEBUF_INIT;
  struct write_data write_data;
  int error;

  memset(&write_data, 0, sizeof(write_data));

  if (cfg->locked) {
    error = git_str_puts(&contents, git_str_cstr(&cfg->locked_content) == NULL ? "" : git_str_cstr(&cfg->locked_content));
  } else {
    if ((error = git_filebuf_open(&file, cfg->file.path,
        GIT_FILEBUF_HASH_SHA256,
        GIT_CONFIG_FILE_MODE)) < 0)
      goto done;

    /* We need to read in our own config file */
    error = git_futils_readbuffer(&contents, cfg->file.path);
  }
  if (error < 0 && error != GIT_ENOTFOUND)
    goto done;

  if ((git_config_parser_init(&parser, cfg->file.path, contents.ptr, contents.size)) < 0)
    goto done;

  ldot = strrchr(key, '.');
  name = ldot + 1;
  section = git__strndup(key, ldot - key);
  GIT_ERROR_CHECK_ALLOC(section);

  ldot = strrchr(orig_key, '.');
  orig_name = ldot + 1;
  orig_section = git__strndup(orig_key, ldot - orig_key);
  GIT_ERROR_CHECK_ALLOC(orig_section);

  write_data.buf = &buf;
  write_data.orig_section = orig_section;
  write_data.section = section;
  write_data.orig_name = orig_name;
  write_data.name = name;
  write_data.preg = preg;
  write_data.value = value;

  if ((error = git_config_parse(&parser, write_on_section, write_on_variable,
              write_on_comment, write_on_eof, &write_data)) < 0)
    goto done;

  if (cfg->locked) {
    size_t len = buf.asize;
    /* Update our copy with the modified contents */
    git_str_dispose(&cfg->locked_content);
    git_str_attach(&cfg->locked_content, git_str_detach(&buf), len);
  } else {
    git_filebuf_write(&file, git_str_cstr(&buf), git_str_len(&buf));

    if ((error = git_filebuf_commit(&file)) < 0)
      goto done;

    if ((error = config_file_refresh_from_buffer(&cfg->parent, buf.ptr, buf.size)) < 0)
      goto done;
  }

done:
  git__free(section);
  git__free(orig_section);
  git_str_dispose(&write_data.buffered_comment);
  git_str_dispose(&buf);
  git_str_dispose(&contents);
  git_filebuf_cleanup(&file);
  git_config_parser_dispose(&parser);

  return error;
}

Coverage Report

Created: 2023-11-19 06:28