// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2007 Jon Loeliger, Freescale Semiconductor, Inc.
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include <stdio.h>

#include "dtc.h"
#include "srcpos.h"

/* A node in our list of directories to search for source/include files */
struct search_path {
        struct search_path *next;       /* next node in list, NULL for end */
        const char *dirname;            /* name of directory to search */
};

/* This is the list of directories that we search for source files */
static struct search_path *search_path_head, **search_path_tail;

/* Detect infinite include recursion. */
#define MAX_SRCFILE_DEPTH     (200)
static int srcfile_depth; /* = 0 */

static char *get_dirname(const char *path)
{
        const char *slash = strrchr(path, '/');

        if (slash) {
                int len = slash - path;
                char *dir = xmalloc(len + 1);

                memcpy(dir, path, len);
                dir[len] = '\0';
                return dir;
        }
        return NULL;
}

FILE *depfile; /* = NULL */
struct srcfile_state *current_srcfile; /* = NULL */
static char *initial_path; /* = NULL */
static int initial_pathlen; /* = 0 */
static bool initial_cpp = true;

static void set_initial_path(char *fname)
{
        int i, len = strlen(fname);

        xasprintf(&initial_path, "%s", fname);
        initial_pathlen = 0;
        for (i = 0; i != len; i++)
                if (initial_path[i] == '/')
                        initial_pathlen++;
}

static char *shorten_to_initial_path(char *fname)
{
        char *p1, *p2, *prevslash1 = NULL;
        int slashes = 0;

        for (p1 = fname, p2 = initial_path; *p1 && *p2; p1++, p2++) {
                if (*p1 != *p2)
                        break;
                if (*p1 == '/') {
                        prevslash1 = p1;
                        slashes++;
                }
        }
        p1 = prevslash1 + 1;
        if (prevslash1) {
                int diff = initial_pathlen - slashes, i, j;
                int restlen = strlen(fname) - (p1 - fname);
                char *res;

                res = xmalloc((3 * diff) + restlen + 1);
                for (i = 0, j = 0; i != diff; i++) {
                        res[j++] = '.';
                        res[j++] = '.';
                        res[j++] = '/';
                }
                strcpy(res + j, p1);
                return res;
        }
        return NULL;
}

/**
 * Returns true if the given path is an absolute one.
 *
 * On Windows, it either needs to begin with a forward slash or with a drive
 * letter (e.g. "C:").
 * On all other operating systems, it must begin with a forward slash to be
 * considered an absolute path.
 */
static bool is_absolute_path(const char *path)
{
#ifdef WIN32
        return (
                path[0] == '/' ||
                (((path[0] >= 'A' && path[0] <= 'Z') || (path[0] >= 'a' && path[0] <= 'z')) && path[1] == ':')
        );
#else
        return (path[0] == '/');
#endif
}

/**
 * Try to open a file in a given directory.
 *
 * If the filename is an absolute path, then dirname is ignored. If it is a
 * relative path, then we look in that directory for the file.
 *
 * @param dirname       Directory to look in, or NULL for none
 * @param fname         Filename to look for
 * @param fp            Set to NULL if file did not open
 * @return allocated filename on success (caller must free), NULL on failure
 */
static char *try_open(const char *dirname, const char *fname, FILE **fp)
{
        char *fullname;

        if (!dirname || is_absolute_path(fname))
                fullname = xstrdup(fname);
        else
                fullname = join_path(dirname, fname);

        *fp = fopen(fullname, "rb");
        if (!*fp) {
                free(fullname);
                fullname = NULL;
        }

        return fullname;
}

/**
 * Open a file for read access
 *
 * If it is a relative filename, we search the full search path for it.
 *
 * @param fname Filename to open
 * @param fp    Returns pointer to opened FILE, or NULL on failure
 * @return pointer to allocated filename, which caller must free
 */
static char *fopen_any_on_path(const char *fname, FILE **fp)
{
        const char *cur_dir = NULL;
        struct search_path *node;
        char *fullname;

        /* Try current directory first */
        assert(fp);
        if (current_srcfile)
                cur_dir = current_srcfile->dir;
        fullname = try_open(cur_dir, fname, fp);

        /* Failing that, try each search path in turn */
        for (node = search_path_head; !*fp && node; node = node->next)
                fullname = try_open(node->dirname, fname, fp);

        return fullname;
}

FILE *srcfile_relative_open(const char *fname, char **fullnamep)
{
        FILE *f;
        char *fullname;

        if (streq(fname, "-")) {
                f = stdin;
                fullname = xstrdup("<stdin>");
        } else {
                fullname = fopen_any_on_path(fname, &f);
                if (!f)
                        die("Couldn't open \"%s\": %s\n", fname,
                            strerror(errno));
        }

        if (depfile) {
                fputc(' ', depfile);
                fprint_path_escaped(depfile, fullname);
        }

        if (fullnamep)
                *fullnamep = fullname;
        else
                free(fullname);

        return f;
}

void srcfile_push(const char *fname)
{
        struct srcfile_state *srcfile;

        if (srcfile_depth++ >= MAX_SRCFILE_DEPTH)
                die("Includes nested too deeply");

        srcfile = xmalloc(sizeof(*srcfile));

        srcfile->f = srcfile_relative_open(fname, &srcfile->name);
        srcfile->dir = get_dirname(srcfile->name);
        srcfile->prev = current_srcfile;

        srcfile->lineno = 1;
        srcfile->colno = 1;

        current_srcfile = srcfile;

        if (srcfile_depth == 1)
                set_initial_path(srcfile->name);
}

bool srcfile_pop(void)
{
        struct srcfile_state *srcfile = current_srcfile;

        assert(srcfile);

        current_srcfile = srcfile->prev;

        if (fclose(srcfile->f))
                die("Error closing \"%s\": %s\n", srcfile->name,
                    strerror(errno));

        /* FIXME: We allow the srcfile_state structure to leak,
         * because it could still be referenced from a location
         * variable being carried through the parser somewhere.  To
         * fix this we could either allocate all the files from a
         * table, or use a pool allocator. */

        return current_srcfile ? true : false;
}

void srcfile_add_search_path(const char *dirname)
{
        struct search_path *node;

        /* Create the node */
        node = xmalloc(sizeof(*node));
        node->next = NULL;
        node->dirname = xstrdup(dirname);

        /* Add to the end of our list */
        if (search_path_tail)
                *search_path_tail = node;
        else
                search_path_head = node;
        search_path_tail = &node->next;
}

void srcpos_update(struct srcpos *pos, const char *text, int len)
{
        int i;

        pos->file = current_srcfile;

        pos->first_line = current_srcfile->lineno;
        pos->first_column = current_srcfile->colno;

        for (i = 0; i < len; i++)
                if (text[i] == '\n') {
                        current_srcfile->lineno++;
                        current_srcfile->colno = 1;
                } else {
                        current_srcfile->colno++;
                }

        pos->last_line = current_srcfile->lineno;
        pos->last_column = current_srcfile->colno;
}

struct srcpos *
srcpos_copy(struct srcpos *pos)
{
        struct srcpos *pos_new;
        struct srcfile_state *srcfile_state;

        if (!pos)
                return NULL;

        pos_new = xmalloc(sizeof(struct srcpos));
        assert(pos->next == NULL);
        memcpy(pos_new, pos, sizeof(struct srcpos));

        /* allocate without free */
        srcfile_state = xmalloc(sizeof(struct srcfile_state));
        memcpy(srcfile_state, pos->file, sizeof(struct srcfile_state));
        pos_new->file = srcfile_state;

        return pos_new;
}

struct srcpos *srcpos_extend(struct srcpos *pos, struct srcpos *newtail)
{
        struct srcpos *p;

        if (!pos)
                return newtail;

        for (p = pos; p->next != NULL; p = p->next);
        p->next = newtail;
        return pos;
}

void srcpos_free(struct srcpos *pos)
{
        struct srcpos *p_next;

        while (pos) {
                p_next = pos->next;
                free(pos);
                pos = p_next;
        }
}

char *
srcpos_string(struct srcpos *pos)
{
        const char *fname = "<no-file>";
        char *pos_str;

        if (pos->file && pos->file->name)
                fname = pos->file->name;


        if (pos->first_line != pos->last_line)
                xasprintf(&pos_str, "%s:%d.%d-%d.%d", fname,
                          pos->first_line, pos->first_column,
                          pos->last_line, pos->last_column);
        else if (pos->first_column != pos->last_column)
                xasprintf(&pos_str, "%s:%d.%d-%d", fname,
                          pos->first_line, pos->first_column,
                          pos->last_column);
        else
                xasprintf(&pos_str, "%s:%d.%d", fname,
                          pos->first_line, pos->first_column);

        return pos_str;
}

static char *
srcpos_string_comment(struct srcpos *pos, bool first_line, int level)
{
        char *pos_str, *fresh_fname = NULL, *first, *rest;
        const char *fname;

        if (!pos) {
                if (level > 1) {
                        xasprintf(&pos_str, "<no-file>:<no-line>");
                        return pos_str;
                } else {
                        return NULL;
                }
        }

        if (!pos->file)
                fname = "<no-file>";
        else if (!pos->file->name)
                fname = "<no-filename>";
        else if (level > 1)
                fname = pos->file->name;
        else {
                fresh_fname = shorten_to_initial_path(pos->file->name);
                if (fresh_fname)
                        fname = fresh_fname;
                else
                        fname = pos->file->name;
        }

        if (level > 1)
                xasprintf(&first, "%s:%d:%d-%d:%d", fname,
                          pos->first_line, pos->first_column,
                          pos->last_line, pos->last_column);
        else
                xasprintf(&first, "%s:%d", fname,
                          first_line ? pos->first_line : pos->last_line);

        if (fresh_fname)
                free(fresh_fname);

        if (pos->next != NULL) {
                rest = srcpos_string_comment(pos->next, first_line, level);
                xasprintf(&pos_str, "%s, %s", first, rest);
                free(first);
                free(rest);
        } else {
                pos_str = first;
        }

        return pos_str;
}

char *srcpos_string_first(struct srcpos *pos, int level)
{
        return srcpos_string_comment(pos, true, level);
}

char *srcpos_string_last(struct srcpos *pos, int level)
{
        return srcpos_string_comment(pos, false, level);
}

void srcpos_verror(struct srcpos *pos, const char *prefix,
                   const char *fmt, va_list va)
{
        char *srcstr;

        srcstr = srcpos_string(pos);

        fprintf(stderr, "%s: %s ", prefix, srcstr);
        vfprintf(stderr, fmt, va);
        fprintf(stderr, "\n");

        free(srcstr);
}

void srcpos_error(struct srcpos *pos, const char *prefix,
                  const char *fmt, ...)
{
        va_list va;

        va_start(va, fmt);
        srcpos_verror(pos, prefix, fmt, va);
        va_end(va);
}

void srcpos_set_line(char *f, int l)
{
        current_srcfile->name = f;
        current_srcfile->lineno = l;

        if (initial_cpp) {
                initial_cpp = false;
                set_initial_path(f);
        }
}