From: Felix Fietkau Date: Thu, 28 Feb 2013 20:50:49 +0000 (+0100) Subject: add json_script, a minimalistic JSON based script interpreter X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=38ea521911a1bf01b3714f1dfc725e941159c0f1;p=project%2Flibubox.git add json_script, a minimalistic JSON based script interpreter Signed-off-by: Felix Fietkau --- diff --git a/CMakeLists.txt b/CMakeLists.txt index ba7ccaa..941fd8e 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -43,7 +43,10 @@ IF(EXISTS ${json}) ADD_EXECUTABLE(jshn jshn.c) TARGET_LINK_LIBRARIES(jshn ${json}) - INSTALL(TARGETS blobmsg_json jshn + ADD_LIBRARY(json_script SHARED json_script.c) + TARGET_LINK_LIBRARIES(json_script ubox) + + INSTALL(TARGETS blobmsg_json jshn json_script LIBRARY DESTINATION lib RUNTIME DESTINATION bin ) diff --git a/json_script.c b/json_script.c new file mode 100644 index 0000000..bc23754 --- /dev/null +++ b/json_script.c @@ -0,0 +1,622 @@ +/* + * Copyright (C) 2013 Felix Fietkau + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +#include +#include + +#include + +#include "json_script.h" + +struct json_call { + struct json_script_ctx *ctx; + struct blob_attr *vars; + unsigned int seq; +}; + +struct json_handler { + const char *name; + int (*cb)(struct json_call *call, struct blob_attr *cur); +}; + +static int json_process_expr(struct json_call *call, struct blob_attr *cur); +static int json_process_cmd(struct json_call *call, struct blob_attr *cur); + +struct json_script_file * +json_script_file_from_blobmsg(const char *name, void *data, int len) +{ + struct json_script_file *f; + char *new_name; + int name_len = 0; + + if (name) + name_len = strlen(name) + 1; + + f = calloc_a(sizeof(*f) + len, &new_name, name_len); + memcpy(f->data, data, len); + if (name) + f->avl.key = strcpy(new_name, name); + + return f; +} + +static struct json_script_file * +json_script_get_file(struct json_script_ctx *ctx, const char *filename) +{ + struct json_script_file *f; + + f = avl_find_element(&ctx->files, filename, f, avl); + if (f) + return f; + + f = ctx->handle_file(ctx, filename); + if (!f) + return NULL; + + avl_insert(&ctx->files, &f->avl); + return f; +} + +static void __json_script_run(struct json_call *call, struct json_script_file *file, + struct blob_attr *context) +{ + struct json_script_ctx *ctx = call->ctx; + + if (file->seq == call->seq) { + if (context) + ctx->handle_error(ctx, "Recursive include", context); + + return; + } + + file->seq = call->seq; + while (file) { + json_process_cmd(call, file->data); + file = file->next; + } +} + +const char *json_script_find_var(struct json_script_ctx *ctx, struct blob_attr *vars, + const char *name) +{ + struct blob_attr *cur; + int rem; + + blobmsg_for_each_attr(cur, vars, rem) { + if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING) + continue; + + if (strcmp(blobmsg_name(cur), name) != 0) + continue; + + return blobmsg_data(cur); + } + + return ctx->handle_var(ctx, name, vars); +} + +static const char * +msg_find_var(struct json_call *call, const char *name) +{ + return json_script_find_var(call->ctx, call->vars, name); +} + +static void +json_get_tuple(struct blob_attr *cur, struct blob_attr **tb, int t1, int t2) +{ + static struct blobmsg_policy expr_tuple[3] = { + { .type = BLOBMSG_TYPE_STRING }, + {}, + {}, + }; + + expr_tuple[1].type = t1; + expr_tuple[2].type = t2; + blobmsg_parse_array(expr_tuple, 3, tb, blobmsg_data(cur), blobmsg_data_len(cur)); +} + +static int handle_if(struct json_call *call, struct blob_attr *expr) +{ + struct blob_attr *tb[4]; + int ret; + + static const struct blobmsg_policy if_tuple[4] = { + { .type = BLOBMSG_TYPE_STRING }, + { .type = BLOBMSG_TYPE_ARRAY }, + { .type = BLOBMSG_TYPE_ARRAY }, + { .type = BLOBMSG_TYPE_ARRAY }, + }; + + blobmsg_parse_array(if_tuple, 4, tb, blobmsg_data(expr), blobmsg_data_len(expr)); + + if (!tb[1] || !tb[2]) + return 0; + + ret = json_process_expr(call, tb[1]); + if (ret < 0) + return 0; + + if (ret) + return json_process_cmd(call, tb[2]); + + if (!tb[3]) + return 0; + + return json_process_cmd(call, tb[3]); +} + +static int handle_case(struct json_call *call, struct blob_attr *expr) +{ + struct blob_attr *tb[3], *cur; + const char *var; + int rem; + + json_get_tuple(expr, tb, BLOBMSG_TYPE_STRING, BLOBMSG_TYPE_TABLE); + if (!tb[1] || !tb[2]) + return 0; + + var = msg_find_var(call, blobmsg_data(tb[1])); + if (!var) + return 0; + + blobmsg_for_each_attr(cur, tb[2], rem) { + if (!strcmp(var, blobmsg_name(cur))) + return json_process_cmd(call, cur); + } + + return 0; +} + +static int handle_return(struct json_call *call, struct blob_attr *expr) +{ + return -2; +} + +static int handle_include(struct json_call *call, struct blob_attr *expr) +{ + struct blob_attr *tb[3]; + struct json_script_file *f; + + json_get_tuple(expr, tb, BLOBMSG_TYPE_STRING, 0); + if (!tb[1]) + return 0; + + f = json_script_get_file(call->ctx, blobmsg_data(tb[1])); + if (!f) + return 0; + + __json_script_run(call, f, expr); + return 0; +} + +static const struct json_handler cmd[] = { + { "if", handle_if }, + { "case", handle_case }, + { "return", handle_return }, + { "include", handle_include }, +}; + +static int eq_regex_cmp(const char *str, const char *pattern, bool regex) +{ + regex_t reg; + int ret; + + if (!regex) + return !strcmp(str, pattern); + + if (regcomp(®, pattern, REG_EXTENDED | REG_NOSUB)) + return 0; + + ret = !regexec(®, str, 0, NULL, 0); + regfree(®); + + return ret; +} + +static int expr_eq_regex(struct json_call *call, struct blob_attr *expr, bool regex) +{ + struct json_script_ctx *ctx = call->ctx; + struct blob_attr *tb[3], *cur; + const char *var; + int rem; + + json_get_tuple(expr, tb, BLOBMSG_TYPE_STRING, 0); + if (!tb[1] || !tb[2]) + return -1; + + var = msg_find_var(call, blobmsg_data(tb[1])); + if (!var) + return 0; + + switch(blobmsg_type(tb[2])) { + case BLOBMSG_TYPE_STRING: + return eq_regex_cmp(var, blobmsg_data(tb[2]), regex); + case BLOBMSG_TYPE_ARRAY: + blobmsg_for_each_attr(cur, tb[2], rem) { + if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING) { + ctx->handle_error(ctx, "Unexpected element type", cur); + return -1; + } + + if (eq_regex_cmp(var, blobmsg_data(cur), regex)) + return 1; + } + return 0; + default: + ctx->handle_error(ctx, "Unexpected element type", tb[2]); + return -1; + } +} + +static int handle_expr_eq(struct json_call *call, struct blob_attr *expr) +{ + return expr_eq_regex(call, expr, false); +} + +static int handle_expr_regex(struct json_call *call, struct blob_attr *expr) +{ + return expr_eq_regex(call, expr, true); +} + +static int handle_expr_has(struct json_call *call, struct blob_attr *expr) +{ + struct json_script_ctx *ctx = call->ctx; + struct blob_attr *tb[3], *cur; + int rem; + + json_get_tuple(expr, tb, 0, 0); + if (!tb[1]) + return -1; + + switch(blobmsg_type(tb[1])) { + case BLOBMSG_TYPE_STRING: + return !!msg_find_var(call, blobmsg_data(tb[1])); + case BLOBMSG_TYPE_ARRAY: + blobmsg_for_each_attr(cur, tb[1], rem) { + if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING) { + ctx->handle_error(ctx, "Unexpected element type", cur); + return -1; + } + + if (msg_find_var(call, blobmsg_data(cur))) + return 1; + } + return 0; + default: + ctx->handle_error(ctx, "Unexpected element type", tb[1]); + return -1; + } +} + +static int expr_and_or(struct json_call *call, struct blob_attr *expr, bool and) +{ + struct blob_attr *cur; + int ret, rem; + int i = 0; + + blobmsg_for_each_attr(cur, expr, rem) { + if (i++ < 1) + continue; + + ret = json_process_expr(call, cur); + if (ret < 0) + return ret; + + if (ret != and) + return ret; + } + + return and; +} + +static int handle_expr_and(struct json_call *call, struct blob_attr *expr) +{ + return expr_and_or(call, expr, 1); +} + +static int handle_expr_or(struct json_call *call, struct blob_attr *expr) +{ + return expr_and_or(call, expr, 0); +} + +static int handle_expr_not(struct json_call *call, struct blob_attr *expr) +{ + struct blob_attr *tb[3]; + + json_get_tuple(expr, tb, BLOBMSG_TYPE_ARRAY, 0); + if (!tb[1]) + return -1; + + return json_process_expr(call, tb[1]); +} + +static const struct json_handler expr[] = { + { "eq", handle_expr_eq }, + { "regex", handle_expr_regex }, + { "has", handle_expr_has }, + { "and", handle_expr_and }, + { "or", handle_expr_or }, + { "not", handle_expr_not }, +}; + +static int +__json_process_type(struct json_call *call, struct blob_attr *cur, + const struct json_handler *h, int n, bool *found) +{ + const char *name = blobmsg_data(blobmsg_data(cur)); + int i; + + for (i = 0; i < n; i++) { + if (strcmp(name, h[i].name) != 0) + continue; + + *found = true; + return h[i].cb(call, cur); + } + + *found = false; + return -1; +} + +static int json_process_expr(struct json_call *call, struct blob_attr *cur) +{ + struct json_script_ctx *ctx = call->ctx; + bool found; + int ret; + + if (blobmsg_type(cur) != BLOBMSG_TYPE_ARRAY || + blobmsg_type(blobmsg_data(cur)) != BLOBMSG_TYPE_STRING) { + ctx->handle_error(ctx, "Unexpected element type", cur); + return -1; + } + + ret = __json_process_type(call, cur, expr, ARRAY_SIZE(expr), &found); + if (!found) + ctx->handle_error(ctx, "Unknown expression type", cur); + + return ret; +} + +static int cmd_add_string(struct json_call *call, const char *pattern) +{ + struct json_script_ctx *ctx = call->ctx; + char *dest, *next, *str; + int len = 0; + bool var = false; + char c = '%'; + + dest = blobmsg_alloc_string_buffer(&ctx->buf, NULL, 1); + next = alloca(strlen(pattern) + 1); + strcpy(next, pattern); + + for (str = next; str; str = next) { + const char *cur; + char *end; + int cur_len = 0; + bool cur_var = var; + + end = strchr(str, '%'); + if (end) { + *end = 0; + next = end + 1; + var = !var; + } else { + end = str + strlen(str); + next = NULL; + } + + if (cur_var) { + if (next > str) { + cur = msg_find_var(call, str); + if (!cur) + continue; + + cur_len = strlen(cur); + } else { + cur = &c; + cur_len = 1; + } + } else { + if (str == end) + continue; + + cur = str; + cur_len = end - str; + } + + dest = blobmsg_realloc_string_buffer(&ctx->buf, cur_len + 1); + memcpy(dest + len, cur, cur_len); + len += cur_len; + } + + if (var) + return -1; + + dest[len] = 0; + blobmsg_add_string_buffer(&ctx->buf); + return 0; +} + +static int cmd_process_strings(struct json_call *call, struct blob_attr *attr) +{ + struct json_script_ctx *ctx = call->ctx; + struct blob_attr *cur; + int args = -1; + int rem, ret; + void *c; + + blob_buf_init(&ctx->buf, 0); + c = blobmsg_open_array(&ctx->buf, NULL); + blobmsg_for_each_attr(cur, attr, rem) { + if (args++ < 0) + continue; + + if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING) { + ctx->handle_error(ctx, "Invalid argument in command", attr); + return -1; + } + + ret = cmd_add_string(call, blobmsg_data(cur)); + if (ret) { + ctx->handle_error(ctx, "Unterminated variable reference in string", attr); + return ret; + } + } + + blobmsg_close_array(&ctx->buf, c); + + return 0; +} + +static int __json_process_cmd(struct json_call *call, struct blob_attr *cur) +{ + struct json_script_ctx *ctx = call->ctx; + const char *name; + bool found; + int ret; + + if (blobmsg_type(cur) != BLOBMSG_TYPE_ARRAY || + blobmsg_type(blobmsg_data(cur)) != BLOBMSG_TYPE_STRING) { + ctx->handle_error(ctx, "Unexpected element type", cur); + return -1; + } + + ret = __json_process_type(call, cur, cmd, ARRAY_SIZE(cmd), &found); + if (found) + return ret; + + name = blobmsg_data(blobmsg_data(cur)); + ret = cmd_process_strings(call, cur); + if (ret) + return ret; + + ctx->handle_command(ctx, name, blob_data(ctx->buf.head), call->vars); + + return 0; +} + +static int json_process_cmd(struct json_call *call, struct blob_attr *block) +{ + struct json_script_ctx *ctx = call->ctx; + struct blob_attr *cur; + int rem; + int ret; + int i = 0; + + if (blobmsg_type(block) != BLOBMSG_TYPE_ARRAY) { + ctx->handle_error(ctx, "Unexpected element type", block); + return -1; + } + + blobmsg_for_each_attr(cur, block, rem) { + switch(blobmsg_type(cur)) { + case BLOBMSG_TYPE_STRING: + if (!i) + return __json_process_cmd(call, block); + default: + ret = json_process_cmd(call, cur); + if (ret < -1) + return ret; + break; + } + i++; + } + + return 0; +} + +void json_script_run(struct json_script_ctx *ctx, const char *name, + struct blob_attr *vars) +{ + struct json_script_file *file; + static unsigned int _seq = 0; + struct json_call call = { + .ctx = ctx, + .vars = vars, + .seq = ++_seq, + }; + + /* overflow */ + if (!call.seq) + call.seq = ++_seq; + + file = json_script_get_file(ctx, name); + if (!file) + return; + + __json_script_run(&call, file, NULL); +} + +static void __json_script_file_free(struct json_script_ctx *ctx, struct json_script_file *f) +{ + struct json_script_file *next; + + for (next = f->next; f; f = next, next = f->next) + free(f); +} + +void +json_script_free(struct json_script_ctx *ctx) +{ + struct json_script_file *f, *next; + + avl_remove_all_elements(&ctx->files, f, avl, next) + __json_script_file_free(ctx, f); + + blob_buf_free(&ctx->buf); +} + +static void +__default_handle_error(struct json_script_ctx *ctx, const char *msg, + struct blob_attr *context) +{ +} + +static const char * +__default_handle_var(struct json_script_ctx *ctx, const char *name, + struct blob_attr *vars) +{ + return NULL; +} + +static int +__default_handle_expr(struct json_script_ctx *ctx, const char *name, + struct blob_attr *expr, struct blob_attr *vars) +{ + return -1; +} + +static struct json_script_file * +__default_handle_file(struct json_script_ctx *ctx, const char *name) +{ + return NULL; +} + +void json_script_init(struct json_script_ctx *ctx) +{ + avl_init(&ctx->files, avl_strcmp, false, NULL); + + if (!ctx->handle_error) + ctx->handle_error = __default_handle_error; + + if (!ctx->handle_var) + ctx->handle_var = __default_handle_var; + + if (!ctx->handle_expr) + ctx->handle_expr = __default_handle_expr; + + if (!ctx->handle_file) + ctx->handle_file = __default_handle_file; +} diff --git a/json_script.h b/json_script.h new file mode 100644 index 0000000..e28b511 --- /dev/null +++ b/json_script.h @@ -0,0 +1,111 @@ +/* + * Copyright (C) 2013 Felix Fietkau + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +#ifndef __JSON_SCRIPT_H +#define __JSON_SCRIPT_H + +#include +#include +#include +#include + +struct json_script_file; + +struct json_script_ctx { + struct avl_tree files; + struct blob_buf buf; + + uint32_t run_seq; + + /* + * handle_command: handle a command that was not recognized by the + * json_script core (required) + * + * @cmd: blobmsg container of the processed command + * @vars: blobmsg container of current run variables + */ + void (*handle_command)(struct json_script_ctx *ctx, const char *name, + struct blob_attr *cmd, struct blob_attr *vars); + + /* + * handle_expr: handle an expression that was not recognized by the + * json_script core (optional) + * + * @expr: blobmsg container of the processed expression + * @vars: blobmsg container of current runtime variables + */ + int (*handle_expr)(struct json_script_ctx *ctx, const char *name, + struct blob_attr *expr, struct blob_attr *vars); + + /* + * handle_var - look up a variable that's not part of the runtime + * variable set (optional) + */ + const char *(*handle_var)(struct json_script_ctx *ctx, const char *name, + struct blob_attr *vars); + + /* + * handle_file - load a file by filename (optional) + * + * in case of wildcards, it can return a chain of json_script files + * linked via the ::next pointer. Only the first json_script file is + * added to the tree. + */ + struct json_script_file *(*handle_file)(struct json_script_ctx *ctx, + const char *name); + + /* + * handle_error - handle a processing error in a command or expression + * (optional) + * + * @msg: error message + * @context: source file context of the error (blobmsg container) + */ + void (*handle_error)(struct json_script_ctx *ctx, const char *msg, + struct blob_attr *context); +}; + +struct json_script_file { + struct avl_node avl; + struct json_script_file *next; + + unsigned int seq; + struct blob_attr data[]; +}; + +void json_script_init(struct json_script_ctx *ctx); +void json_script_free(struct json_script_ctx *ctx); + +/* + * json_script_run - run a json script with a set of runtime variables + * + * @filename: initial filename to run + * @vars: blobmsg container of the current runtime variables + */ +void json_script_run(struct json_script_ctx *ctx, const char *filename, + struct blob_attr *vars); + +struct json_script_file * +json_script_file_from_blobmsg(const char *name, void *data, int len); + +/* + * json_script_find_var - helper function to find a runtime variable from + * the list passed by json_script user. + * It is intended to be used by the .handle_var callback + */ +const char *json_script_find_var(struct json_script_ctx *ctx, struct blob_attr *vars, + const char *name); + +#endif