8577 libstand: add stpcpy stpncpy

[unleashed.git] / tools / mkconfig / main.c

/*
 * Copyright (c) 2016-2017 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <stdlib.h>
#include <stddef.h>
#include <libgen.h>

#include <jeffpc/jeffpc.h>
#include <jeffpc/error.h>
#include <jeffpc/io.h>
#include <jeffpc/sexpr.h>

#include "main.h"

/*
 * Config
 * ======
 *
 * Each config item is represented by a list:
 *
 * (config
 *   NAME
 *   default-value)
 *
 * For example:
 *
 * (config
 *   LINUX_CORE_SUPPORT
 *   #t)
 *
 * This generates the following line when -H is specified:
 *
 * #define CONFIG_LINUX_CORE_SUPPORT
 *
 * and the following line when -M is specified:
 *
 * CONFIG_LINUX_CORE_SUPPORT=y
 *
 * Some configuration item do not should never be changed, however it is
 * convenient to keep track of them using config files.  To make it
 * paintfully obvious that these should not be changed (and later on
 * possibly give hints to an interactive configuration tool), one can use
 * const statements instead.  They have the same syntax as config
 * statements:
 *
 * (const
 *   NAME
 *   value)
 *
 * For example:
 *
 * (const
 *   MACH
 *   'amd64)
 *
 * The generated makefile and header lines are indistinguishable from config
 * statement lines.
 *
 * Select
 * ------
 *
 * In some cases, the domain of the values is narrower than the domain of
 * all integers, booleans, strings, etc.  For these cases, there is the
 * select statement.  For example, given the following statement:
 *
 * (select
 *   PLATFORM
 *   ('i86pc 'i86xpv))
 *
 * The only possible values for CONFIG_PLATFORM are i86pc and i86xpv.  The
 * default is the first value listed.
 *
 * Mapping of Default Values
 * -------------------------
 *
 * bool true (#t):
 *
 *      #define CONFIG_FOO
 *      CONFIG_FOO=y
 *
 * bool false (#f):
 *
 *      #undef CONFIG_FOO
 *      CONFIG_FOO=n
 *
 * int (e.g., 5):
 *
 *      #define CONFIG_FOO 5
 *      CONFIG_FOO=5
 *
 * string (e.g., "abc")
 *
 *      #define CONFIG_FOO "abc"
 *      CONFIG_FOO="abc"
 *
 * quoted symbol (e.g., 'abc)
 *
 *      #define CONFIG_FOO abc
 *      CONFIG_FOO=abc
 *
 * Unquoted symbols are subject to evaluation.  For example, given the
 * this config:
 *
 *      ((config
 *         FOO
 *         5)
 *
 *       (config
 *         BAR
 *         FOO))
 *
 * We would end up with:
 *
 *      #define CONFIG_FOO 5
 *      #define CONFIG_BAR 5
 *
 * and
 *
 *      CONFIG_FOO=5
 *      CONFIG_BAR=5
 *
 * since when generating the CONFIG_BAR line, we evaluate the expression (FOO)
 * and obtain 5.
 *
 * Evaluation
 * ----------
 *
 * The values in config and const statements are subject to evaluation.  As
 * stated above, strings, integers, booleans and quoted symbols evaluate to
 * themselves.
 *
 * Unquoted symbols and lists are evaluated using a handful of simple built-in
 * functions.  The resulting value is used in the generated output file. This
 * allows for complex expressions without having to worry if every part of the
 * build system supports them (e.g., bitshifts).
 *
 * The supported functions include:
 *
 *      (or ...)
 *      (and ...)
 *      (+ ...)
 *      (* ...)
 *
 * TODO: expand
 *
 * Include
 * =======
 *
 * It is possible to include files by using the include statement:
 *
 * (include "filename")
 *
 * This includes the contents of the specified file as if they were included
 * in place of the include statement.
 */

#define CONFIG_STMT     "config"
#define CONST_STMT      "const"
#define SELECT_STMT     "select"
#define INCLUDE_STMT    "include"

enum gen_what {
        GEN_HEADER,
        GEN_MAKEFILE,
        GEN_MAKEFILE_DMAKE,
};
#define NGEN (GEN_MAKEFILE_DMAKE + 1)

static avl_tree_t mapping_tree;
static list_t mapping_list;
static const char *include_guard_name = "__CONFIG_H";

static int cmp(const void *va, const void *vb)
{
        const struct config_item *a = va;
        const struct config_item *b = vb;
        int ret;

        ret = strcmp(str_cstr(a->name), str_cstr(b->name));
        if (ret < 0)
                return -1;
        else if (ret > 0)
                return 1;
        return 0;
}

static struct val *config_lookup(struct str *name, void *private)
{
        struct config_item key = {
                .name = name,
        };
        struct config_item *ci;

        ci = avl_find(&mapping_tree, &key, NULL);

        str_putref(name);

        /*
         * We're supposed to return "code", so we wrap the value in a quote.
         * If we returned a value instead (e.g., i386), sexpr_eval() would
         * try to evaluate that - by looking up the symbol.
         */
        return VAL_ALLOC_CONS(VAL_ALLOC_SYM_CSTR("quote"),
                              VAL_ALLOC_CONS(val_getref(ci->value), NULL));
}

struct mapping {
        void (*file_start)(FILE *);
        void (*file_end)(FILE *);
        void (*entry[VT_CONS + 1])(FILE *, const struct str *, struct val *);
};

static struct mapping mapping[NGEN]; /* forward decl */

static void __map_int(FILE *f, const char *pfx, const char *name,
                      const char *sep, const uint64_t val)
{
        fprintf(f, "%sCONFIG_%s%s%"PRIu64"\n", pfx, name, sep, val);
}

static void map_int_header(FILE *f, const struct str *name, struct val *val)
{
        __map_int(f, "#define\t", str_cstr(name), " ", val->i);
}

static void map_int_makefile(FILE *f, const struct str *name, struct val *val)
{
        __map_int(f, "", str_cstr(name), "=", val->i);
}

static void __map_str(FILE *f, const char *pfx, const char *name,
                      const char *sep, const char *val, bool quoted)
{
        const char *q = quoted ? "\"" : "";

        fprintf(f, "%sCONFIG_%s%s%s%s%s\n", pfx, name, sep, q, val, q);
}

static void map_str_header(FILE *f, const struct str *name, struct val *val)
{
        // XXX: return val with quotes escaped
        __map_str(f, "#define\t", str_cstr(name), " ", str_cstr(val->str), true);
}

static void map_str_makefile(FILE *f, const struct str *name, struct val *val)
{
        // XXX: return val with quotes escaped
        __map_str(f, "", str_cstr(name), "=", str_cstr(val->str), true);
}

static void map_sym_header(FILE *f, const struct str *name, struct val *val)
{
        /* produce the symbol as well as a stringified version */
        __map_str(f, "#define\t", str_cstr(name), " ", str_cstr(val->str), false);
        __map_str(f, "#define\t", str_cstr(name), "_STR ", str_cstr(val->str), true);
}

static void map_sym_makefile(FILE *f, const struct str *name, struct val *val)
{
        /* produce the symbol as well as a stringified version */
        __map_str(f, "", str_cstr(name), "=", str_cstr(val->str), false);
        __map_str(f, "", str_cstr(name), "_STR=", str_cstr(val->str), true);
}

static void map_bool_header(FILE *f, const struct str *name,
                            struct val *val)
{
        if (val->b)
                fprintf(f, "#define\tCONFIG_%s\n", str_cstr(name));
        else
                fprintf(f, "#undef\tCONFIG_%s\n", str_cstr(name));
}

static void map_bool_makefile(FILE *f, const struct str *name,
                              struct val *val)
{
        fprintf(f, "CONFIG_%s=%s\n", str_cstr(name), val->b ? "y" : "n");
}

static void map_bool_makefile_dmake(FILE *f, const struct str *name,
                                    struct val *val)
{
        fprintf(f, "CONFIG_%s=%s\n", str_cstr(name), val->b ? "" : "$(POUND_SIGN)");
}

static void map_cons(FILE *f, const struct str *name, struct val *val)
{
        /*
         * All VT_CONS value should have been evaluated away into ints,
         * bools, strings, and symbols.
         */
        panic("We should never be mapping a VT_CONS");
}

static void map_file_start_header(FILE *f)
{
        fprintf(f, "/* GENERATED FILE - DO NOT EDIT */\n");
        fprintf(f, "\n");
        fprintf(f, "#ifndef\t%s\n", include_guard_name);
        fprintf(f, "#define\t%s\n", include_guard_name);
        fprintf(f, "\n");
}

static void map_file_end_header(FILE *f)
{
        fprintf(f, "\n");
        fprintf(f, "#endif\n");
}

static void map_file_start_makefile(FILE *f)
{
        fprintf(f, "# GENERATED FILE - DO NOT EDIT\n");
        fprintf(f, "\n");
}

static void map_file_start_makefile_dmake(FILE *f)
{
        fprintf(f, "# GENERATED FILE - DO NOT EDIT\n");
        fprintf(f, "\n");
        fprintf(f, "PRE_POUND=pre\\#\n");
        fprintf(f, "POUND_SIGN=$(PRE_POUND:pre\\%%=%%)\n");
        fprintf(f, "\n");
}

static struct mapping mapping[NGEN] = {
        [GEN_HEADER] = {
                .file_start = map_file_start_header,
                .file_end = map_file_end_header,
                .entry = {
                        [VT_INT] = map_int_header,
                        [VT_STR] = map_str_header,
                        [VT_SYM] = map_sym_header,
                        [VT_BOOL] = map_bool_header,
                        [VT_CONS] = map_cons,
                },
        },
        [GEN_MAKEFILE] = {
                .file_start = map_file_start_makefile,
                .entry = {
                        [VT_INT] = map_int_makefile,
                        [VT_STR] = map_str_makefile,
                        [VT_SYM] = map_sym_makefile,
                        [VT_BOOL] = map_bool_makefile,
                        [VT_CONS] = map_cons,
                },
        },
        [GEN_MAKEFILE_DMAKE] = {
                .file_start = map_file_start_makefile_dmake,
                .entry = {
                        [VT_INT] = map_int_makefile,
                        [VT_STR] = map_str_makefile,
                        [VT_SYM] = map_sym_makefile,
                        [VT_BOOL] = map_bool_makefile_dmake,
                        [VT_CONS] = map_cons,
                },
        },
};

static char *prog;

static void __config(struct val *args, enum config_item_type type)
{
        struct val *name = sexpr_nth(val_getref(args), 1);
        struct val *value = sexpr_nth(val_getref(args), 2);
        struct config_item *item;

        if (name->type != VT_SYM)
                die("name not a VT_SYM");

        item = malloc(sizeof(struct config_item));
        if (!item)
                die("failed to allocate config item");

        item->name = str_getref(name->str);
        item->defvalue = val_getref(value);
        item->type = type;

        avl_add(&mapping_tree, item);
        list_insert_tail(&mapping_list, item);

        val_putref(name);
        val_putref(value);
}

static void __select(struct val *args)
{
        struct val *name = sexpr_nth(val_getref(args), 1);
        struct val *value = sexpr_nth(val_getref(args), 2);
        struct config_item *item;

        if (name->type != VT_SYM)
                die("name not a VT_SYM");

        item = malloc(sizeof(struct config_item));
        if (!item)
                die("failed to allocate config item");

        item->name = str_getref(name->str);
        item->defvalue = val_getref(value);
        item->type = CIT_SELECT;

        avl_add(&mapping_tree, item);
        list_insert_tail(&mapping_list, item);

        val_putref(name);
        val_putref(value);
}

static int process(int dirfd, const char *infile);

static void __include(int dirfd, struct val *args)
{
        struct val *fname = sexpr_nth(val_getref(args), 1);
        char *dname;
        char *bname;
        int dir;

        if (fname->type != VT_STR)
                die("fname not a VT_STR");

        dname = strdup(str_cstr(fname->str));
        bname = strdup(str_cstr(fname->str));

        dir = xopenat(dirfd, dirname(dname), O_RDONLY, 0);

        ASSERT0(process(dir, basename(bname)));

        xclose(dir);

        free(bname);
        free(dname);

        val_putref(fname);
}

static int process(int dirfd, const char *infile)
{
        struct val *cur;
        char *in;

        in = read_file_at(dirfd, infile);
        if (IS_ERR(in)) {
                fprintf(stderr, "%s: cannot read: %s\n",
                        infile, xstrerror(PTR_ERR(in)));
                die("failed");
        }

        cur = sexpr_parse(in, strlen(in));

        free(in);

        while (cur != NULL) {
                struct val *item = sexpr_car(val_getref(cur));
                struct val *stmt = sexpr_car(val_getref(item));
                struct val *args = sexpr_cdr(val_getref(item));
                struct val *next = sexpr_cdr(cur);

                if (item->type != VT_CONS)
                        die("item not a VT_CONS");
                if (stmt->type != VT_SYM)
                        die("statement not a VT_SYM");

                if (strcmp(str_cstr(stmt->str), CONFIG_STMT) == 0) {
                        __config(args, CIT_CONFIG);
                } else if (strcmp(str_cstr(stmt->str), CONST_STMT) == 0) {
                        __config(args, CIT_CONST);
                } else if (strcmp(str_cstr(stmt->str), SELECT_STMT) == 0) {
                        __select(args);
                } else if (strcmp(str_cstr(stmt->str), INCLUDE_STMT) == 0) {
                        __include(dirfd, args);
                } else {
                        die("unknown statement");
                }

                val_putref(item);
                val_putref(stmt);
                val_putref(args);
                cur = next;
        }

        VERIFY3P(cur, ==, NULL);

        return 0;
}

static inline struct val *get_val_atom(struct config_item *ci)
{
        return val_getref(ci->defvalue);
}

static inline struct val *get_val_sym(struct config_item *ci)
{
        return sexpr_eval(val_getref(ci->defvalue), config_lookup, NULL);
}

static inline struct val *get_val_expr(struct config_item *ci)
{
        return sexpr_eval(val_getref(ci->defvalue), config_lookup, NULL);
}

static inline struct val *get_val_select(struct config_item *ci)
{
        /* grab the first option */
        return sexpr_eval(sexpr_car(val_getref(ci->defvalue)), NULL, NULL);
}

/* figure out config items' values */
static void eval(void)
{
        struct config_item *cur;

        /* use defaults for all atoms */
        for (cur = list_head(&mapping_list);
             cur != NULL;
             cur = list_next(&mapping_list, cur)) {
                ASSERT3P(cur->value, ==, NULL);

                switch (cur->defvalue->type) {
                        case VT_INT:
                        case VT_STR:
                        case VT_BOOL:
                                cur->value = get_val_atom(cur);
                                break;
                        case VT_SYM:
                        case VT_CONS:
                                /* skip these for now */
                                break;
                }
        }

        /* fill in all the rest (i.e., those with VT_CONS & VT_SYM defaults) */
        for (cur = list_head(&mapping_list);
             cur != NULL;
             cur = list_next(&mapping_list, cur)) {
                if (cur->value)
                        continue; /* already set */

                switch (cur->defvalue->type) {
                        case VT_INT:
                        case VT_STR:
                        case VT_BOOL:
                                panic("config item %p (%s) found empty", cur,
                                      str_cstr(cur->name));
                        case VT_SYM:
                                cur->value = get_val_sym(cur);
                                break;
                        case VT_CONS:
                                if (cur->type != CIT_SELECT)
                                        cur->value = get_val_expr(cur);
                                else
                                        cur->value = get_val_select(cur);
                                break;
                }
        }
}

/* print out the config items */
static void map(const char *outfile, enum gen_what what)
{
        struct mapping *m = &mapping[what];
        struct config_item *cur;
        FILE *f;

        if (!outfile)
                f = stdout;
        else
                f = fopen(outfile, "w");

        if (m->file_start)
                m->file_start(f);

        for (cur = list_head(&mapping_list);
             cur != NULL;
             cur = list_next(&mapping_list, cur)) {
                struct val *value;

                value = val_getref(cur->value);

                m->entry[value->type](f, cur->name, value);

                val_putref(value);
        }

        if (m->file_end)
                m->file_end(f);

        if (outfile)
                fclose(f);
}

static void usage(void)
{
        fprintf(stderr, "Usage: %s {-H | -M | -m} [-I <guard name>] "
                "[-o <outfile>] <infile>\n", prog);
        exit(2);
}

int main(int argc, char **argv)
{
        enum gen_what what = GEN_HEADER;
        const char *outfile = NULL;
        char opt;

        prog = argv[0];

        ASSERT0(putenv("UMEM_DEBUG=default,verbose"));
        ASSERT0(putenv("BLAHG_DISABLE_SYSLOG=1"));

        jeffpc_init(NULL);

        avl_create(&mapping_tree, cmp, sizeof(struct config_item),
                   offsetof(struct config_item, tree));
        list_create(&mapping_list, sizeof(struct config_item),
                    offsetof(struct config_item, list));

        while ((opt = getopt(argc, argv, "HI:Mmo:")) != -1) {
                switch (opt) {
                        case 'H':
                                /* header */
                                what = GEN_HEADER;
                                break;
                        case 'I':
                                include_guard_name = optarg;
                                break;
                        case 'M':
                                /* makefile (bmake) */
                                what = GEN_MAKEFILE;
                                break;
                        case 'm':
                                /* makefile (dmake) */
                                what = GEN_MAKEFILE_DMAKE;
                                break;
                        case 'o':
                                /* output file */
                                outfile = optarg;
                                break;
                        default:
                                usage();
                                break;
                }
        }

        if (optind == argc)
                usage();

        /*
         * Start processing by faking a config which looks like:
         *
         *      ((include "<the path user specified>"))
         *
         * This allows make relative path includes work properly.  We could
         * alternatively do the same path munging that __include() does
         * here, but that would duplicate some ugly code.
         */
        __include(AT_FDCWD, VAL_ALLOC_CONS(VAL_ALLOC_CSTR(argv[argc - 1]), NULL));

        eval();

        map(outfile, what);

        return 0;
}