ngx_http_script.c

Nginx是一个高性能的HTTP和反向代理服务器

/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


#define ngx_http_script_exit  (u_char *) &ngx_http_script_exit_code

static uintptr_t ngx_http_script_exit_code = (uintptr_t) NULL;


ngx_uint_t
ngx_http_script_variables_count(ngx_str_t *value)
{
    ngx_uint_t  i, n;

    for (n = 0, i = 0; i < value->len; i++) {
        if (value->data[i] == '$') {
            n++;
        }
    }

    return n;
}


ngx_int_t
ngx_http_script_compile(ngx_http_script_compile_t *sc)
{
    u_char                                ch;
    size_t                                size;
    ngx_int_t                             index, *p;
    ngx_str_t                             name;
    uintptr_t                            *code;
    ngx_uint_t                            i, n, bracket;
    ngx_http_script_var_code_t           *var_code;
    ngx_http_script_copy_code_t          *copy;
    ngx_http_script_copy_capture_code_t  *copy_capture;

    if (sc->flushes && *sc->flushes == NULL) {
        n = sc->variables ? sc->variables : 1;
        *sc->flushes = ngx_array_create(sc->cf->pool, n, sizeof(ngx_uint_t));
        if (*sc->flushes == NULL) {
            return NGX_ERROR;
        }
    }


    if (*sc->lengths == NULL) {
        n = sc->variables * (2 * sizeof(ngx_http_script_copy_code_t)
                             + sizeof(ngx_http_script_var_code_t))
            + sizeof(uintptr_t);

        *sc->lengths = ngx_array_create(sc->cf->pool, n, 1);
        if (*sc->lengths == NULL) {
            return NGX_ERROR;
        }
    }


    if (*sc->values == NULL) {
        n = (sc->variables * (2 * sizeof(ngx_http_script_copy_code_t)
                              + sizeof(ngx_http_script_var_code_t))
                + sizeof(uintptr_t)
                + sc->source->len
                + sizeof(uintptr_t) - 1)
            & ~(sizeof(uintptr_t) - 1);

        *sc->values = ngx_array_create(sc->cf->pool, n, 1);
        if (*sc->values == NULL) {
            return NGX_ERROR;
        }
    }

    sc->variables = 0;

    for (i = 0; i < sc->source->len; /* void */ ) {

        name.len = 0;

        if (sc->source->data[i] == '$') {

            if (++i == sc->source->len) {
                goto invalid_variable;
            }

            if (sc->source->data[i] >= '1' && sc->source->data[i] <= '9') {

                n = sc->source->data[i] - '0';

                if (sc->captures_mask & (1 << n)) {
                    sc->dup_capture = 1;
                }

                sc->captures_mask |= 1 << n;

                copy_capture = ngx_http_script_add_code(*sc->lengths,
                                   sizeof(ngx_http_script_copy_capture_code_t),
                                   NULL);
                if (copy_capture == NULL) {
                    return NGX_ERROR;
                }

                copy_capture->code = (ngx_http_script_code_pt)
                                         ngx_http_script_copy_capture_len_code;
                copy_capture->n = 2 * n;


                copy_capture = ngx_http_script_add_code(*sc->values,
                                   sizeof(ngx_http_script_copy_capture_code_t),
                                   &sc->main);
                if (copy_capture == NULL) {
                    return NGX_ERROR;
                }

                copy_capture->code = ngx_http_script_copy_capture_code;
                copy_capture->n = 2 * n;

                if (sc->ncaptures < n) {
                    sc->ncaptures = n;
                }

                i++;

                continue;
            }

            if (sc->source->data[i] == '{') {
                bracket = 1;

                if (++i == sc->source->len) {
                    goto invalid_variable;
                }

                name.data = &sc->source->data[i];

            } else {
                bracket = 0;
                name.data = &sc->source->data[i];
            }

            for ( /* void */ ; i < sc->source->len; i++, name.len++) {
                ch = sc->source->data[i];

                if (ch == '}' && bracket) {
                    i++;
                    bracket = 0;
                    break;
                }

                if ((ch >= 'A' && ch <= 'Z')
                    || (ch >= 'a' && ch <= 'z')
                    || (ch >= '0' && ch <= '9')
                    || ch == '_')
                {
                    continue;
                }

                break;
            }

            if (bracket) {
                ngx_conf_log_error(NGX_LOG_EMERG, sc->cf, 0,
                                   "the closing bracket in \"%V\" "
                                   "variable is missing", &name);
                return NGX_ERROR;
            }

            if (name.len == 0) {
                goto invalid_variable;
            }

            sc->variables++;

            index = ngx_http_get_variable_index(sc->cf, &name);

            if (index == NGX_ERROR) {
                return NGX_ERROR;
            }

            if (sc->flushes) {
                p = ngx_array_push(*sc->flushes);
                if (p == NULL) {
                    return NGX_ERROR;
                }

                *p = index;
            }

            var_code = ngx_http_script_add_code(*sc->lengths,
                                            sizeof(ngx_http_script_var_code_t),
                                            NULL);
            if (var_code == NULL) {
                return NGX_ERROR;
            }

            var_code->code = (ngx_http_script_code_pt)
                                            ngx_http_script_copy_var_len_code;
            var_code->index = (uintptr_t) index;


            var_code = ngx_http_script_add_code(*sc->values,
                                            sizeof(ngx_http_script_var_code_t),
                                            &sc->main);
            if (var_code == NULL) {
                return NGX_ERROR;
            }

            var_code->code = ngx_http_script_copy_var_code;
            var_code->index = (uintptr_t) index;

            continue;
        }

        if (sc->source->data[i] == '?' && sc->compile_args) {
            sc->args = 1;
            sc->compile_args = 0;

            code = ngx_http_script_add_code(*sc->lengths, sizeof(uintptr_t),
                                            NULL);
            if (code == NULL) {
                return NGX_ERROR;
            }

            *code = (uintptr_t) ngx_http_script_mark_args_code;

            code = ngx_http_script_add_code(*sc->values, sizeof(uintptr_t),
                                            &sc->main);
            if (code == NULL) {
                return NGX_ERROR;
            }

            *code = (uintptr_t) ngx_http_script_start_args_code;

            i++;

            continue;
        }

        name.data = &sc->source->data[i];

        while (i < sc->source->len
               && sc->source->data[i] != '$'
               && !(sc->source->data[i] == '?' && sc->compile_args))
        {
            i++;
            name.len++;
        }

        sc->size += name.len;

        copy = ngx_http_script_add_code(*sc->lengths,
                                        sizeof(ngx_http_script_copy_code_t),
                                        NULL);
        if (copy == NULL) {
            return NGX_ERROR;
        }

        copy->code = (ngx_http_script_code_pt) ngx_http_script_copy_len_code;
        copy->len = name.len;

        size = (sizeof(ngx_http_script_copy_code_t) + name.len
                   + sizeof(uintptr_t) - 1)
                & ~(sizeof(uintptr_t) - 1);

        copy = ngx_http_script_add_code(*sc->values, size, &sc->main);
        if (copy == NULL) {
            return NGX_ERROR;
        }

        copy->code = ngx_http_script_copy_code;
        copy->len = name.len;

        ngx_memcpy((u_char *) copy + sizeof(ngx_http_script_copy_code_t),
                   name.data, name.len);
    }

    if (sc->complete_lengths) {
        code = ngx_http_script_add_code(*sc->lengths, sizeof(uintptr_t), NULL);
        if (code == NULL) {
            return NGX_ERROR;
        }

        *code = (uintptr_t) NULL;
    }

    if (sc->complete_values) {
        code = ngx_http_script_add_code(*sc->values, sizeof(uintptr_t),
                                        &sc->main);
        if (code == NULL) {
            return NGX_ERROR;
        }

        *code = (uintptr_t) NULL;
    }

    return NGX_OK;

invalid_variable:

    ngx_conf_log_error(NGX_LOG_EMERG, sc->cf, 0, "invalid variable name");

    return NGX_ERROR;
}


u_char *
ngx_http_script_run(ngx_http_request_t *r, ngx_str_t *value,
    void *code_lengths, size_t len, void *code_values)
{
    ngx_uint_t                    i;
    ngx_http_script_code_pt       code;
    ngx_http_script_len_code_pt   lcode;
    ngx_http_script_engine_t      e;
    ngx_http_core_main_conf_t    *cmcf;

    cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);

    for (i = 0; i < cmcf->variables.nelts; i++) {
        if (r->variables[i].no_cacheable) {
            r->variables[i].valid = 0;
            r->variables[i].not_found = 0;
        }
    }

    ngx_memzero(&e, sizeof(ngx_http_script_engine_t));

    e.ip = code_lengths;
    e.request = r;
    e.flushed = 1;

    while (*(uintptr_t *) e.ip) {
        lcode = *(ngx_http_script_len_code_pt *) e.ip;
        len += lcode(&e);
    }


    value->len = len;
    value->data = ngx_palloc(r->pool, len);
    if (value->data == NULL) {
        return NULL;
    }

    e.ip = code_values;
    e.pos = value->data;

    while (*(uintptr_t *) e.ip) {
        code = *(ngx_http_script_code_pt *) e.ip;
        code((ngx_http_script_engine_t *) &e);
    }

    return e.pos;
}


void
ngx_http_script_flush_no_cacheable_variables(ngx_http_request_t *r,
    ngx_array_t *indices)
{
    ngx_uint_t  n, *index;

    if (indices) {
        index = indices->elts;
        for (n = 0; n < indices->nelts; n++) {
            if (r->variables[index[n]].no_cacheable) {
                r->variables[index[n]].valid = 0;
                r->variables[index[n]].not_found = 0;
            }
        }
    }
}


void *
ngx_http_script_start_code(ngx_pool_t *pool, ngx_array_t **codes, size_t size)
{
    if (*codes == NULL) {
        *codes = ngx_array_create(pool, 256, 1);
        if (*codes == NULL) {
            return NULL;
        }
    }

    return ngx_array_push_n(*codes, size);
}


void *
ngx_http_script_add_code(ngx_array_t *codes, size_t size, void *code)
{
    u_char  *elts, **p;
    void    *new;

    elts = codes->elts;

    new = ngx_array_push_n(codes, size);
    if (new == NULL) {
        return NGX_CONF_ERROR;
    }

    if (code) {
        if (elts != codes->elts) {
            p = code;
            *p += (u_char *) codes->elts - elts;
        }
    }