radmod2json.c

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/*
 * radmod2json.c   Dump FreeRADIUS v4 module conf_parser_t and call_env_parser_t
 *                 definitions as JSON.
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 *
 * Copyright (C) 2026 Arran Cudbard-Bell <a.cudbardb@freeradius.org>
 */
RCSID("$Id: 0e0912605fad3a45b88816c2ebd273d8cae134e3 $")
 
#include <freeradius-devel/server/base.h>
#include <freeradius-devel/server/cf_parse.h>
#include <freeradius-devel/server/dl_module.h>
#include <freeradius-devel/server/module.h>
#include <freeradius-devel/server/module_rlm.h>
#include <freeradius-devel/server/section.h>
#include <freeradius-devel/unlang/call_env.h>
#include <freeradius-devel/unlang/base.h>
#include <freeradius-devel/util/atexit.h>
#include <freeradius-devel/util/dl.h>
#include <freeradius-devel/util/types.h>
 
#include <freeradius-devel/json/base.h>
 
#include <dirent.h>
#include <dlfcn.h>
#include <sys/wait.h>
 
#ifdef HAVE_GETOPT_H
#  include <getopt.h>
#endif
 
char const *radiusd_version = RADIUSD_VERSION_BUILD("radmod2json");
 
/*
 *      Symbolic names for the five quote tokens, keyed by `fr_token_t`.
 *      fr_table_str_by_value() routes us through fr_table_indexed_str_by_num
 *      via the _Generic dispatch on the table type.
 */
/*
 *      `fr_token_to_enum_str()` (src/lib/util/token.c) returns the
 *      source-identifier form of the token ("T_BARE_WORD" etc.) which
 *      is what the converter's rule layer greps for.
 */
#define quote_name(_t) fr_token_to_enum_str(_t)
 
/*
 *      Resolve a function pointer back to its source symbol name via dladdr().
 *      macOS C symbols get a leading '_' from the linker - strip that before
 *      emitting.
 */
static struct json_object *func_symbol(void const *fn)
{
        Dl_info     info;
        char const *name;
 
        if (!fn) return NULL;
        if (dladdr(fn, &info) == 0) return NULL;
        if (!info.dli_sname) return NULL;
 
        name = info.dli_sname;
        if (name[0] == '_') name++;
        return json_object_new_string(name);
}
 
static struct json_object *build_dflt(char const *value, fr_token_t quote)
{
        struct json_object *o;
 
        if (!value) return NULL;
        o = json_object_new_object();
        json_object_object_add(o, "value", json_object_new_string(value));
        json_object_object_add(o, "quote", json_object_new_string(quote_name(quote)));
        return o;
}
 
/*
 *      Walk every set bit of `flags`; resolve each single-bit mask
 *      through the library's `*_flag_to_enum_str()` lookup.  Bits with
 *      no symbolic name are skipped.  The result preserves bit-order.
 */
static struct json_object *build_conf_parser_flags(conf_parser_flags_t flags)
{
        struct json_object *a = json_object_new_array();
 
        for (size_t bit = 0; bit < 32; bit++) {
                uint64_t    mask = UINT64_C(1) << bit;
                char const *name;
 
                if (!(flags & mask)) continue;
                name = cf_parser_flag_to_enum_str(mask);
                if (!name) continue;
                json_object_array_add(a, json_object_new_string(name));
        }
        return a;
}
 
static struct json_object *build_conf_parser_rules(conf_parser_t const *rules);
 
static struct json_object *build_conf_parser_rule(conf_parser_t const *r)
{
        struct json_object *o      = json_object_new_object();
        bool                is_sub = (r->flags & CONF_FLAG_SUBSECTION) != 0;
        char const         *name1  = (r->name1 == CF_IDENT_ANY) ? NULL : r->name1;
        char const         *name2  = (r->name2 == CF_IDENT_ANY) ? NULL : r->name2;
 
        json_object_object_add(o, "name1", name1 ? json_object_new_string(name1) : NULL);
        json_object_object_add(o, "name2", name2 ? json_object_new_string(name2) : NULL);
        json_object_object_add(o, "type", json_object_new_string(fr_type_to_enum_str(r->type)));
        json_object_object_add(o, "flags", build_conf_parser_flags(r->flags));
        json_object_object_add(o, "func", func_symbol((void const *)r->func));
        json_object_object_add(o, "on_read", func_symbol((void const *)r->on_read));
 
        if (is_sub) {
                json_object_object_add(o, "subcs",
                                       r->subcs ? build_conf_parser_rules(r->subcs) : json_object_new_array());
        } else {
                json_object_object_add(o, "dflt", build_dflt(r->dflt, r->quote));
        }
 
        return o;
}
 
static struct json_object *build_conf_parser_rules(conf_parser_t const *rules)
{
        struct json_object *a = json_object_new_array();
 
        if (rules) {
                for (conf_parser_t const *r = rules; r->name1; r++) {
                        /*
                         *      A CONF_FLAG_REF rule references another
                         *      conf_parser_t array whose rules are parsed as if
                         *      they appeared inline in this section.  Splice the
                         *      referenced rules straight into this array rather
                         *      than emitting a rule for the reference itself.
                         *
                         *      Note that `dflt` and `subcs` share a union, so a
                         *      REF rule must never reach build_conf_parser_rule():
                         *      its non-subsection branch would read the `subcs`
                         *      pointer as a `dflt` string.
                         */
                        if (r->flags & CONF_FLAG_REF) {
                                struct json_object *ref = build_conf_parser_rules(r->subcs);
                                size_t              n   = json_object_array_length(ref);
 
                                for (size_t i = 0; i < n; i++) {
                                        json_object_array_add(a, json_object_get(json_object_array_get_idx(ref, i)));
                                }
                                json_object_put(ref);
                                continue;
                        }
 
                        json_object_array_add(a, build_conf_parser_rule(r));
                }
        }
        return a;
}
 
static struct json_object *build_call_env_flags(call_env_flags_t flags)
{
        struct json_object *a = json_object_new_array();
 
        for (size_t bit = 0; bit < 32; bit++) {
                uint64_t    mask = UINT64_C(1) << bit;
                char const *name;
 
                if (!(flags & mask)) continue;
                name = call_env_flag_to_enum_str(mask);
                if (!name) continue;
                json_object_array_add(a, json_object_new_string(name));
        }
        return a;
}
 
static struct json_object *json_section_ident(char const *name)
{
        if (!name) return NULL;
        if (name == CF_IDENT_ANY) return json_object_new_string("*");
        return json_object_new_string(name);
}
 
static struct json_object *build_call_env_rules(call_env_parser_t const *rules);
 
static struct json_object *build_call_env_rule(call_env_parser_t const *r)
{
        struct json_object *o      = json_object_new_object();
        bool                is_sub = (r->flags & CALL_ENV_FLAG_SUBSECTION) != 0;
 
        json_object_object_add(o, "name", json_section_ident(r->name));
        json_object_object_add(o, "flags", build_call_env_flags(r->flags));
 
        if (is_sub) {
                struct json_object *s = json_object_new_object();
                json_object_object_add(s, "name2", json_section_ident(r->section.name2));
                json_object_object_add(s, "func", func_symbol((void const *)r->section.func));
                json_object_object_add(s, "subcs",
                                       r->section.subcs ? build_call_env_rules(r->section.subcs) :
                                                          json_object_new_array());
                json_object_object_add(o, "section", s);
        } else {
                struct json_object *p      = json_object_new_object();
                struct json_object *parsed = json_object_new_object();
 
                /*
                 *      FR_TYPE_NULL / FR_TYPE_VOID both mean "no cast" - the
                 *      framework hands the parsed value through without
                 *      coercion.  Collapse to a JSON null so the converter
                 *      only has to check one sentinel.
                 */
                json_object_object_add(p, "cast_type",
                                       ((r->pair.cast_type == FR_TYPE_NULL) || (r->pair.cast_type == FR_TYPE_VOID)) ?
                                               NULL :
                                               json_object_new_string(fr_type_to_enum_str(r->pair.cast_type)));
                json_object_object_add(p, "type",
                                       json_object_new_string(call_env_result_type_to_enum_str(r->pair.type)));
                json_object_object_add(p, "dflt", build_dflt(r->pair.dflt, r->pair.dflt_quote));
                json_object_object_add(p, "func", func_symbol((void const *)r->pair.func));
 
                json_object_object_add(parsed, "type",
                                       json_object_new_string(call_env_parse_type_to_enum_str(r->pair.parsed.type)));
                json_object_object_add(p, "parsed", parsed);
 
                json_object_object_add(o, "pair", p);
        }
 
        return o;
}
 
static struct json_object *build_call_env_rules(call_env_parser_t const *rules)
{
        struct json_object *a = json_object_new_array();
 
        if (rules) {
                for (call_env_parser_t const *r = rules; r->name; r++) {
                        json_object_array_add(a, build_call_env_rule(r));
                }
        }
        return a;
}
 
static struct json_object *build_method_bindings(module_method_binding_t const *bindings)
{
        struct json_object *a = json_object_new_array();
 
        if (bindings) {
                for (module_method_binding_t const *b = bindings; b->section; b++) {
                        struct json_object *entry   = json_object_new_object();
                        struct json_object *section = json_object_new_object();
 
                        json_object_object_add(section, "name1", json_section_ident(b->section->name1));
                        json_object_object_add(section, "name2", json_section_ident(b->section->name2));
                        json_object_object_add(entry, "section", section);
                        json_object_object_add(entry, "method", func_symbol((void const *)b->method));
                        json_object_object_add(entry, "env",
                                               (b->method_env && b->method_env->env) ?
                                                       build_call_env_rules(b->method_env->env) :
                                                       json_object_new_array());
 
                        json_object_array_add(a, entry);
                }
        }
 
        return a;
}
 
/*
 *      Build the JSON for one module using the server's normal dl loader.
 *      `bare_name` is the module name without the "rlm_" prefix (so "files"
 *      for rlm_files).  Returns the json object or NULL on error.
 */
static struct json_object *build_module(char const *bare_name)
{
        dl_module_t        *dl_module;
        module_rlm_t       *m;
        struct json_object *entry;
 
        dl_module = dl_module_alloc(NULL, bare_name, DL_MODULE_TYPE_MODULE);
        if (!dl_module) {
                fr_perror("rlm_%s", bare_name);
                return NULL;
        }
 
        m = (module_rlm_t *)dl_module->exported;
        if (!m) return NULL;
 
        entry = json_object_new_object();
        json_object_object_add(entry, "module", json_object_new_string(m->common.name ? m->common.name : bare_name));
        json_object_object_add(entry, "config", build_conf_parser_rules(m->common.config));
        json_object_object_add(entry, "call_env", build_method_bindings(m->method_group.bindings));
        return entry;
}
 
static int dump_module(struct json_object *modules, char const *bare_name)
{
        int   fds[2];
        pid_t pid;
        int   status;
 
        if (pipe(fds) < 0) {
                fprintf(stderr, "rlm_%s: pipe failed: %s\n", bare_name, fr_syserror(errno));
                return -1;
        }
 
        pid = fork();
        if (pid < 0) {
                close(fds[0]);
                close(fds[1]);
                fprintf(stderr, "rlm_%s: fork failed: %s\n", bare_name, fr_syserror(errno));
                return -1;
        }
 
        if (pid == 0) {
                struct json_object *entry;
 
                close(fds[0]);
                entry = build_module(bare_name);
                if (!entry) {
                        fprintf(stderr, "rlm_%s: build_module failed\n", bare_name);
                        _exit(1);
                }
 
                {
                        char const *s = json_object_to_json_string_ext(entry, JSON_C_TO_STRING_PLAIN |
                                                                                      JSON_C_TO_STRING_NOSLASHESCAPE);
                        size_t  remaining = strlen(s);
                        ssize_t n;
 
                        while (remaining > 0) {
                                n = write(fds[1], s, remaining);
                                if (n < 0) {
                                        fprintf(stderr, "rlm_%s: write to pipe failed: %s\n",
                                                bare_name, fr_syserror(errno));
                                        _exit(1);
                                }
                                s += n;
                                remaining -= n;
                        }
                }
                json_object_put(entry);
                close(fds[1]);
                _exit(0);
        }
 
        close(fds[1]);
        {
                char    buf[262144];
                size_t  used = 0;
                ssize_t n;
                while ((n = read(fds[0], buf + used, sizeof(buf) - 1 - used)) > 0) {
                        used += n;
                        if (used >= sizeof(buf) - 1) break;
                }
                close(fds[0]);
                if (used >= sizeof(buf) - 1) {
                        fprintf(stderr, "rlm_%s: overflowed buffer reading JSON\n", bare_name);
                        return -1;
                }
                buf[used] = '\0';
 
                waitpid(pid, &status, 0);
 
                if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
                        fprintf(stderr, "rlm_%s: child %s (status=0x%x), skipping\n", bare_name,
                                WIFEXITED(status) ? "exited non-zero" : "crashed", status);
                        return -1;
                }
 
                if (used > 0) {
                        struct json_object *entry = json_tokener_parse(buf);
                        if (entry) {
                                json_object_array_add(modules, entry);
                                return 0;
                        }
                        fprintf(stderr, "rlm_%s: failed to parse child JSON\n", bare_name);
                        return -1;
                }
        }
 
        return -1;
}
 
/*
 *      Discover top-level rlm_*.dylib (or .so) files in a directory, returning
 *      the bare module names (no "rlm_" prefix, no extension).  The dl loader
 *      will re-prefix and resolve the full path itself.
 */
static int discover_modules(TALLOC_CTX *ctx, char const *dir, char ***out_names, size_t *out_count)
{
        DIR           *d;
        struct dirent *e;
        char         **names = NULL;
        size_t         n = 0, alloc = 0;
        size_t         extlen = strlen(DL_EXTENSION);
 
        d = opendir(dir);
        if (!d) {
                fprintf(stderr, "Failed opening module dir %s: %s\n", dir, fr_syserror(errno));
                return -1;
        }
 
        while ((e = readdir(d)) != NULL) {
                size_t nlen = strlen(e->d_name);
 
                if (nlen <= extlen) continue;
                if (strcmp(e->d_name + nlen - extlen, DL_EXTENSION) != 0) continue;
                if (strncmp(e->d_name, "rlm_", 4) != 0) continue;
 
                if (n == alloc) {
                        alloc = alloc ? alloc * 2 : 16;
                        MEM(names = talloc_realloc(ctx, names, char *, alloc));
                }
 
                /* Strip "rlm_" prefix and DL_EXTENSION suffix */
                MEM(names[n++] = talloc_strndup(names, e->d_name + 4, nlen - 4 - extlen));
        }
 
        closedir(d);
 
        *out_names = names;
        *out_count = n;
        return 0;
}
 
static int compare_str(void const *a, void const *b)
{
        return strcmp(*(char *const *)a, *(char *const *)b);
}
 
static NEVER_RETURNS void usage(int rcode)
{
        FILE *fp = (rcode == 0) ? stdout : stderr;
 
        fprintf(fp,
                "Usage: radmod2json [options]\n"
                "  -m <list>     Comma-separated list of module names without rlm_ prefix\n"
                "                (default: every rlm_*" DL_EXTENSION " under the module directory).\n"
                "  -M <dir>      Module directory to load from (default: " LIBDIR ").\n"
                "  -D <dict>     Dictionary directory (default: " DICTDIR ").\n"
                "  -o <file>     Write JSON to <file> (default stdout).\n"
                "  -x            Enable debug output (repeatable).\n"
                "  -h            This help.\n");
        exit(rcode);
}
 
int main(int argc, char *argv[])
{
        int                 c;
        int                 rcode       = EXIT_SUCCESS;
        char const         *modules_arg = NULL;
        char const         *output_file = NULL;
        char const         *module_dir  = LIBDIR;
        char const         *dict_dir    = DICTDIR;
        char              **names       = NULL;
        size_t              n_names     = 0;
        fr_dict_t          *internal    = NULL;
        TALLOC_CTX         *autofree;
 
        autofree = talloc_autofree_context();
 
        fr_debug_lvl    = 0;
        default_log.dst = L_DST_STDERR;
        default_log.fd  = STDERR_FILENO;
 
        while ((c = getopt(argc, argv, "D:hm:M:o:x")) != -1) {
                switch (c) {
                case 'D':
                        dict_dir = optarg;
                        break;
                case 'h':
                        usage(EXIT_SUCCESS);
                case 'm':
                        modules_arg = optarg;
                        break;
                case 'M':
                        module_dir = optarg;
                        break;
                case 'o':
                        output_file = optarg;
                        break;
                case 'x':
                        fr_debug_lvl++;
                        break;
                default:
                        usage(EXIT_FAILURE);
                }
        }
 
        if (fr_check_lib_magic(RADIUSD_MAGIC_NUMBER) < 0) {
                fr_perror("radmod2json");
                exit(EXIT_FAILURE);
        }
 
        /* Init the dl loader against the requested module dir. */
        modules_init(module_dir);
 
        /*
         *      dl_module_alloc triggers fr_dict_autoload on the loaded
         *      module, which needs a global dict ctx to exist.  Some
         *      modules also autoload internal-protocol attributes that
         *      are in the dictionary tree, so load it up front.
         */
        if (!fr_dict_global_ctx_init(NULL, true, dict_dir)) {
                fr_perror("radmod2json");
                exit(EXIT_FAILURE);
        }
 
        if (fr_dict_internal_afrom_file(&internal, FR_DICTIONARY_INTERNAL_DIR, __FILE__) < 0) {
                fr_perror("radmod2json");
                exit(EXIT_FAILURE);
        }
 
        if (request_global_init() < 0) {
                fr_perror("radmod2json");
                exit(EXIT_FAILURE);
        }
 
        if (unlang_global_init() < 0) {
                fr_perror("radmod2json");
                exit(EXIT_FAILURE);
        }
 
        if (modules_arg) {
                char  *list = talloc_strdup(autofree, modules_arg);
                char  *p, *tok;
                size_t alloc = 0;
 
                for (p = list; (tok = strsep(&p, ",")) != NULL;) {
                        char const *bare = tok;
 
                        if (!*bare) continue;
                        if (strncmp(bare, "rlm_", 4) == 0) bare += 4;
                        if (n_names == alloc) {
                                alloc = alloc ? alloc * 2 : 16;
                                MEM(names = talloc_realloc(autofree, names, char *, alloc));
                        }
                        names[n_names++] = UNCONST(char *, bare);
                }
        } else {
                if (discover_modules(autofree, module_dir, &names, &n_names) < 0) {
                        exit(EXIT_FAILURE);
                }
                if (n_names > 0) qsort(names, n_names, sizeof(names[0]), compare_str);
        }
 
        {
                struct json_object *root = json_object_new_object();
                struct json_object *modules = json_object_new_array();
                char const *json_str;
 
                json_object_object_add(root, "modules", modules);
 
                for (size_t i = 0; i < n_names; i++) {
                        if (dump_module(modules, names[i]) < 0) rcode = EXIT_FAILURE;
                }
 
                json_str = json_object_to_json_string_ext(root, JSON_C_TO_STRING_PRETTY | JSON_C_TO_STRING_NOSLASHESCAPE);
                if (output_file) {
                        FILE *out = fopen(output_file, "w");
                        if (!out) {
                                fprintf(stderr, "Failed opening %s: %s\n", output_file, fr_syserror(errno));
                                exit(EXIT_FAILURE);
                        }
                        fputs(json_str, out);
                        fputc('\n', out);
                        fclose(out);
                } else {
                        fputs(json_str, stdout);
                        fputc('\n', stdout);
                }
 
                json_object_put(root);
        }
 
        return rcode;
}