Merge pull request #1770 from ethomson/index_fuzz

[libgit2.git] / src / attr_file.c

#include "common.h"
#include "repository.h"
#include "filebuf.h"
#include "attr.h"
#include "git2/blob.h"
#include "git2/tree.h"
#include <ctype.h>

static int sort_by_hash_and_name(const void *a_raw, const void *b_raw);
static void git_attr_rule__clear(git_attr_rule *rule);
static bool parse_optimized_patterns(
        git_attr_fnmatch *spec,
        git_pool *pool,
        const char *pattern);

int git_attr_file__new(
        git_attr_file **attrs_ptr,
        git_attr_file_source from,
        const char *path,
        git_pool *pool)
{
        git_attr_file *attrs = NULL;

        attrs = git__calloc(1, sizeof(git_attr_file));
        GITERR_CHECK_ALLOC(attrs);

        if (pool)
                attrs->pool = pool;
        else {
                attrs->pool = git__calloc(1, sizeof(git_pool));
                if (!attrs->pool || git_pool_init(attrs->pool, 1, 0) < 0)
                        goto fail;
                attrs->pool_is_allocated = true;
        }

        if (path) {
                size_t len = strlen(path);

                attrs->key = git_pool_malloc(attrs->pool, (uint32_t)len + 3);
                GITERR_CHECK_ALLOC(attrs->key);

                attrs->key[0] = '0' + from;
                attrs->key[1] = '#';
                memcpy(&attrs->key[2], path, len);
                attrs->key[len + 2] = '\0';
        }

        if (git_vector_init(&attrs->rules, 4, NULL) < 0)
                goto fail;

        *attrs_ptr = attrs;
        return 0;

fail:
        git_attr_file__free(attrs);
        attrs_ptr = NULL;
        return -1;
}

int git_attr_file__parse_buffer(
        git_repository *repo, void *parsedata, const char *buffer, git_attr_file *attrs)
{
        int error = 0;
        const char *scan = NULL;
        char *context = NULL;
        git_attr_rule *rule = NULL;

        GIT_UNUSED(parsedata);

        assert(buffer && attrs);

        scan = buffer;

        /* if subdir file path, convert context for file paths */
        if (attrs->key && git__suffixcmp(attrs->key, "/" GIT_ATTR_FILE) == 0) {
                context = attrs->key + 2;
                context[strlen(context) - strlen(GIT_ATTR_FILE)] = '\0';
        }

        while (!error && *scan) {
                /* allocate rule if needed */
                if (!rule) {
                        if (!(rule = git__calloc(1, sizeof(git_attr_rule)))) {
                                error = -1;
                                break;
                        }
                        rule->match.flags = GIT_ATTR_FNMATCH_ALLOWNEG |
                                GIT_ATTR_FNMATCH_ALLOWMACRO;
                }

                /* parse the next "pattern attr attr attr" line */
                if (!(error = git_attr_fnmatch__parse(
                                &rule->match, attrs->pool, context, &scan)) &&
                        !(error = git_attr_assignment__parse(
                                repo, attrs->pool, &rule->assigns, &scan)))
                {
                        if (rule->match.flags & GIT_ATTR_FNMATCH_MACRO)
                                /* should generate error/warning if this is coming from any
                                 * file other than .gitattributes at repo root.
                                 */
                                error = git_attr_cache__insert_macro(repo, rule);
                        else
                                error = git_vector_insert(&attrs->rules, rule);
                }

                /* if the rule wasn't a pattern, on to the next */
                if (error < 0) {
                        git_attr_rule__clear(rule); /* reset rule contents */
                        if (error == GIT_ENOTFOUND)
                                error = 0;
                } else {
                        rule = NULL; /* vector now "owns" the rule */
                }
        }

        git_attr_rule__free(rule);

        /* restore file path used for context */
        if (context)
                context[strlen(context)] = '.'; /* first char of GIT_ATTR_FILE */

        return error;
}

int git_attr_file__new_and_load(
        git_attr_file **attrs_ptr,
        const char *path)
{
        int error;
        git_buf content = GIT_BUF_INIT;

        if ((error = git_attr_file__new(attrs_ptr, 0, path, NULL)) < 0)
                return error;

        if (!(error = git_futils_readbuffer(&content, path)))
                error = git_attr_file__parse_buffer(
                        NULL, NULL, git_buf_cstr(&content), *attrs_ptr);

        git_buf_free(&content);

        if (error) {
                git_attr_file__free(*attrs_ptr);
                *attrs_ptr = NULL;
        }

        return error;
}

void git_attr_file__clear_rules(git_attr_file *file)
{
        unsigned int i;
        git_attr_rule *rule;

        git_vector_foreach(&file->rules, i, rule)
                git_attr_rule__free(rule);

        git_vector_free(&file->rules);
}

void git_attr_file__free(git_attr_file *file)
{
        if (!file)
                return;

        git_attr_file__clear_rules(file);

        if (file->pool_is_allocated) {
                git_pool_clear(file->pool);
                git__free(file->pool);
        }
        file->pool = NULL;

        git__free(file);
}

uint32_t git_attr_file__name_hash(const char *name)
{
        uint32_t h = 5381;
        int c;
        assert(name);
        while ((c = (int)*name++) != 0)
                h = ((h << 5) + h) + c;
        return h;
}


int git_attr_file__lookup_one(
        git_attr_file *file,
        const git_attr_path *path,
        const char *attr,
        const char **value)
{
        size_t i;
        git_attr_name name;
        git_attr_rule *rule;

        *value = NULL;

        name.name = attr;
        name.name_hash = git_attr_file__name_hash(attr);

        git_attr_file__foreach_matching_rule(file, path, i, rule) {
                size_t pos;

                if (!git_vector_bsearch(&pos, &rule->assigns, &name)) {
                        *value = ((git_attr_assignment *)
                                          git_vector_get(&rule->assigns, pos))->value;
                        break;
                }
        }

        return 0;
}


bool git_attr_fnmatch__match(
        git_attr_fnmatch *match,
        const git_attr_path *path)
{
        int fnm;
        int icase_flags = (match->flags & GIT_ATTR_FNMATCH_ICASE) ? FNM_CASEFOLD : 0;

        if (match->flags & GIT_ATTR_FNMATCH_DIRECTORY && !path->is_dir)
                return false;

        if (match->flags & GIT_ATTR_FNMATCH_FULLPATH)
                fnm = p_fnmatch(match->pattern, path->path, FNM_PATHNAME | icase_flags);
        else if (path->is_dir)
                fnm = p_fnmatch(match->pattern, path->basename, FNM_LEADING_DIR | icase_flags);
        else
                fnm = p_fnmatch(match->pattern, path->basename, icase_flags);

        return (fnm == FNM_NOMATCH) ? false : true;
}

bool git_attr_rule__match(
        git_attr_rule *rule,
        const git_attr_path *path)
{
        bool matched = git_attr_fnmatch__match(&rule->match, path);

        if (rule->match.flags & GIT_ATTR_FNMATCH_NEGATIVE)
                matched = !matched;

        return matched;
}


git_attr_assignment *git_attr_rule__lookup_assignment(
        git_attr_rule *rule, const char *name)
{
        size_t pos;
        git_attr_name key;
        key.name = name;
        key.name_hash = git_attr_file__name_hash(name);

        if (git_vector_bsearch(&pos, &rule->assigns, &key))
                return NULL;

        return git_vector_get(&rule->assigns, pos);
}

int git_attr_path__init(
        git_attr_path *info, const char *path, const char *base)
{
        ssize_t root;

        /* build full path as best we can */
        git_buf_init(&info->full, 0);

        if (git_path_join_unrooted(&info->full, path, base, &root) < 0)
                return -1;

        info->path = info->full.ptr + root;

        /* remove trailing slashes */
        while (info->full.size > 0) {
                if (info->full.ptr[info->full.size - 1] != '/')
                        break;
                info->full.size--;
        }
        info->full.ptr[info->full.size] = '\0';

        /* skip leading slashes in path */
        while (*info->path == '/')
                info->path++;

        /* find trailing basename component */
        info->basename = strrchr(info->path, '/');
        if (info->basename)
                info->basename++;
        if (!info->basename || !*info->basename)
                info->basename = info->path;

        info->is_dir = (int)git_path_isdir(info->full.ptr);

        return 0;
}

void git_attr_path__free(git_attr_path *info)
{
        git_buf_free(&info->full);
        info->path = NULL;
        info->basename = NULL;
}

/*
 * From gitattributes(5):
 *
 * Patterns have the following format:
 *
 * - A blank line matches no files, so it can serve as a separator for
 *   readability.
 *
 * - A line starting with # serves as a comment.
 *
 * - An optional prefix ! which negates the pattern; any matching file
 *   excluded by a previous pattern will become included again. If a negated
 *   pattern matches, this will override lower precedence patterns sources.
 *
 * - If the pattern ends with a slash, it is removed for the purpose of the
 *   following description, but it would only find a match with a directory. In
 *   other words, foo/ will match a directory foo and paths underneath it, but
 *   will not match a regular file or a symbolic link foo (this is consistent
 *   with the way how pathspec works in general in git).
 *
 * - If the pattern does not contain a slash /, git treats it as a shell glob
 *   pattern and checks for a match against the pathname without leading
 *   directories.
 *
 * - Otherwise, git treats the pattern as a shell glob suitable for consumption
 *   by fnmatch(3) with the FNM_PATHNAME flag: wildcards in the pattern will
 *   not match a / in the pathname. For example, "Documentation/\*.html" matches
 *   "Documentation/git.html" but not "Documentation/ppc/ppc.html". A leading
 *   slash matches the beginning of the pathname; for example, "/\*.c" matches
 *   "cat-file.c" but not "mozilla-sha1/sha1.c".
 */

/*
 * This will return 0 if the spec was filled out,
 * GIT_ENOTFOUND if the fnmatch does not require matching, or
 * another error code there was an actual problem.
 */
int git_attr_fnmatch__parse(
        git_attr_fnmatch *spec,
        git_pool *pool,
        const char *source,
        const char **base)
{
        const char *pattern, *scan;
        int slash_count, allow_space;

        assert(spec && base && *base);

        if (parse_optimized_patterns(spec, pool, *base))
                return 0;

        spec->flags = (spec->flags & GIT_ATTR_FNMATCH__INCOMING);
        allow_space = ((spec->flags & GIT_ATTR_FNMATCH_ALLOWSPACE) != 0);

        pattern = *base;

        while (git__isspace(*pattern)) pattern++;
        if (!*pattern || *pattern == '#') {
                *base = git__next_line(pattern);
                return GIT_ENOTFOUND;
        }

        if (*pattern == '[' && (spec->flags & GIT_ATTR_FNMATCH_ALLOWMACRO) != 0) {
                if (strncmp(pattern, "[attr]", 6) == 0) {
                        spec->flags = spec->flags | GIT_ATTR_FNMATCH_MACRO;
                        pattern += 6;
                }
                /* else a character range like [a-e]* which is accepted */
        }

        if (*pattern == '!' && (spec->flags & GIT_ATTR_FNMATCH_ALLOWNEG) != 0) {
                spec->flags = spec->flags | GIT_ATTR_FNMATCH_NEGATIVE;
                pattern++;
        }

        slash_count = 0;
        for (scan = pattern; *scan != '\0'; ++scan) {
                /* scan until (non-escaped) white space */
                if (git__isspace(*scan) && *(scan - 1) != '\\') {
                        if (!allow_space || (*scan != ' ' && *scan != '\t'))
                                break;
                }

                if (*scan == '/') {
                        spec->flags = spec->flags | GIT_ATTR_FNMATCH_FULLPATH;
                        slash_count++;
                        if (pattern == scan)
                                pattern++;
                }
                /* remember if we see an unescaped wildcard in pattern */
                else if (git__iswildcard(*scan) &&
                        (scan == pattern || (*(scan - 1) != '\\')))
                        spec->flags = spec->flags | GIT_ATTR_FNMATCH_HASWILD;
        }

        *base = scan;

        if ((spec->length = scan - pattern) == 0)
                return GIT_ENOTFOUND;

        if (pattern[spec->length - 1] == '/') {
                spec->length--;
                spec->flags = spec->flags | GIT_ATTR_FNMATCH_DIRECTORY;
                if (--slash_count <= 0)
                        spec->flags = spec->flags & ~GIT_ATTR_FNMATCH_FULLPATH;
        }

        if ((spec->flags & GIT_ATTR_FNMATCH_FULLPATH) != 0 &&
                source != NULL && git_path_root(pattern) < 0)
        {
                size_t sourcelen = strlen(source);
                /* given an unrooted fullpath match from a file inside a repo,
                 * prefix the pattern with the relative directory of the source file
                 */
                spec->pattern = git_pool_malloc(
                        pool, (uint32_t)(sourcelen + spec->length + 1));
                if (spec->pattern) {
                        memcpy(spec->pattern, source, sourcelen);
                        memcpy(spec->pattern + sourcelen, pattern, spec->length);
                        spec->length += sourcelen;
                        spec->pattern[spec->length] = '\0';
                }
        } else {
                spec->pattern = git_pool_strndup(pool, pattern, spec->length);
        }

        if (!spec->pattern) {
                *base = git__next_line(pattern);
                return -1;
        } else {
                /* strip '\' that might have be used for internal whitespace */
                spec->length = git__unescape(spec->pattern);
        }

        return 0;
}

static bool parse_optimized_patterns(
        git_attr_fnmatch *spec,
        git_pool *pool,
        const char *pattern)
{
        if (!pattern[1] && (pattern[0] == '*' || pattern[0] == '.')) {
                spec->flags = GIT_ATTR_FNMATCH_MATCH_ALL;
                spec->pattern = git_pool_strndup(pool, pattern, 1);
                spec->length = 1;

                return true;
        }

        return false;
}

static int sort_by_hash_and_name(const void *a_raw, const void *b_raw)
{
        const git_attr_name *a = a_raw;
        const git_attr_name *b = b_raw;

        if (b->name_hash < a->name_hash)
                return 1;
        else if (b->name_hash > a->name_hash)
                return -1;
        else
                return strcmp(b->name, a->name);
}

static void git_attr_assignment__free(git_attr_assignment *assign)
{
        /* name and value are stored in a git_pool associated with the
         * git_attr_file, so they do not need to be freed here
         */
        assign->name = NULL;
        assign->value = NULL;
        git__free(assign);
}

static int merge_assignments(void **old_raw, void *new_raw)
{
        git_attr_assignment **old = (git_attr_assignment **)old_raw;
        git_attr_assignment *new = (git_attr_assignment *)new_raw;

        GIT_REFCOUNT_DEC(*old, git_attr_assignment__free);
        *old = new;
        return GIT_EEXISTS;
}

int git_attr_assignment__parse(
        git_repository *repo,
        git_pool *pool,
        git_vector *assigns,
        const char **base)
{
        int error;
        const char *scan = *base;
        git_attr_assignment *assign = NULL;

        assert(assigns && !assigns->length);

        git_vector_set_cmp(assigns, sort_by_hash_and_name);

        while (*scan && *scan != '\n') {
                const char *name_start, *value_start;

                /* skip leading blanks */
                while (git__isspace(*scan) && *scan != '\n') scan++;

                /* allocate assign if needed */
                if (!assign) {
                        assign = git__calloc(1, sizeof(git_attr_assignment));
                        GITERR_CHECK_ALLOC(assign);
                        GIT_REFCOUNT_INC(assign);
                }

                assign->name_hash = 5381;
                assign->value = git_attr__true;

                /* look for magic name prefixes */
                if (*scan == '-') {
                        assign->value = git_attr__false;
                        scan++;
                } else if (*scan == '!') {
                        assign->value = git_attr__unset; /* explicit unspecified state */
                        scan++;
                } else if (*scan == '#') /* comment rest of line */
                        break;

                /* find the name */
                name_start = scan;
                while (*scan && !git__isspace(*scan) && *scan != '=') {
                        assign->name_hash =
                                ((assign->name_hash << 5) + assign->name_hash) + *scan;
                        scan++;
                }
                if (scan == name_start) {
                        /* must have found lone prefix (" - ") or leading = ("=foo")
                         * or end of buffer -- advance until whitespace and continue
                         */
                        while (*scan && !git__isspace(*scan)) scan++;
                        continue;
                }

                /* allocate permanent storage for name */
                assign->name = git_pool_strndup(pool, name_start, scan - name_start);
                GITERR_CHECK_ALLOC(assign->name);

                /* if there is an equals sign, find the value */
                if (*scan == '=') {
                        for (value_start = ++scan; *scan && !git__isspace(*scan); ++scan);

                        /* if we found a value, allocate permanent storage for it */
                        if (scan > value_start) {
                                assign->value = git_pool_strndup(pool, value_start, scan - value_start);
                                GITERR_CHECK_ALLOC(assign->value);
                        }
                }

                /* expand macros (if given a repo with a macro cache) */
                if (repo != NULL && assign->value == git_attr__true) {
                        git_attr_rule *macro =
                                git_attr_cache__lookup_macro(repo, assign->name);

                        if (macro != NULL) {
                                unsigned int i;
                                git_attr_assignment *massign;

                                git_vector_foreach(&macro->assigns, i, massign) {
                                        GIT_REFCOUNT_INC(massign);

                                        error = git_vector_insert_sorted(
                                                assigns, massign, &merge_assignments);
                                        if (error < 0 && error != GIT_EEXISTS)
                                                return error;
                                }
                        }
                }

                /* insert allocated assign into vector */
                error = git_vector_insert_sorted(assigns, assign, &merge_assignments);
                if (error < 0 && error != GIT_EEXISTS)
                        return error;

                /* clear assign since it is now "owned" by the vector */
                assign = NULL;
        }

        if (assign != NULL)
                git_attr_assignment__free(assign);

        *base = git__next_line(scan);

        return (assigns->length == 0) ? GIT_ENOTFOUND : 0;
}

static void git_attr_rule__clear(git_attr_rule *rule)
{
        unsigned int i;
        git_attr_assignment *assign;

        if (!rule)
                return;

        if (!(rule->match.flags & GIT_ATTR_FNMATCH_IGNORE)) {
                git_vector_foreach(&rule->assigns, i, assign)
                        GIT_REFCOUNT_DEC(assign, git_attr_assignment__free);
                git_vector_free(&rule->assigns);
        }

        /* match.pattern is stored in a git_pool, so no need to free */
        rule->match.pattern = NULL;
        rule->match.length = 0;
}

void git_attr_rule__free(git_attr_rule *rule)
{
        git_attr_rule__clear(rule);
        git__free(rule);
}