diff options
Diffstat (limited to 'modules/loggers/mod_log_forensic.c')
| -rw-r--r-- | modules/loggers/mod_log_forensic.c | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/modules/loggers/mod_log_forensic.c b/modules/loggers/mod_log_forensic.c new file mode 100644 index 0000000..bb808e8 --- /dev/null +++ b/modules/loggers/mod_log_forensic.c @@ -0,0 +1,289 @@ +/* Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/* + * See also support/check_forensic. + * Relate the forensic log to the transfer log by including + * %{forensic-id}n in the custom log format, for example: + * CustomLog logs/custom "%h %l %u %t \"%r\" %>s %b %{forensic-id}n" + * + * Credit is due to Tina Bird <tbird precision-guesswork.com>, whose + * idea this module was. + * + * Ben Laurie 29/12/2003 + */ + +#include "httpd.h" +#include "http_config.h" +#include "http_log.h" +#include "apr_strings.h" +#include "apr_atomic.h" +#include "http_protocol.h" +#include "test_char.h" +#if APR_HAVE_UNISTD_H +#include <unistd.h> +#endif + +module AP_MODULE_DECLARE_DATA log_forensic_module; + +typedef struct fcfg { + const char *logname; + apr_file_t *fd; +} fcfg; + +static apr_uint32_t next_id; + +static void *make_forensic_log_scfg(apr_pool_t *p, server_rec *s) +{ + fcfg *cfg = apr_pcalloc(p, sizeof *cfg); + + cfg->logname = NULL; + cfg->fd = NULL; + + return cfg; +} + +static void *merge_forensic_log_scfg(apr_pool_t *p, void *parent, void *new) +{ + fcfg *cfg = apr_pcalloc(p, sizeof *cfg); + fcfg *pc = parent; + fcfg *nc = new; + + cfg->logname = apr_pstrdup(p, nc->logname ? nc->logname : pc->logname); + cfg->fd = NULL; + + return cfg; +} + +static int open_log(server_rec *s, apr_pool_t *p) +{ + fcfg *cfg = ap_get_module_config(s->module_config, &log_forensic_module); + + if (!cfg->logname || cfg->fd) + return 1; + + if (*cfg->logname == '|') { + piped_log *pl; + const char *pname = ap_server_root_relative(p, cfg->logname + 1); + + pl = ap_open_piped_log(p, pname); + if (pl == NULL) { + ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00650) + "couldn't spawn forensic log pipe %s", cfg->logname); + return 0; + } + cfg->fd = ap_piped_log_write_fd(pl); + } + else { + const char *fname = ap_server_root_relative(p, cfg->logname); + apr_status_t rv; + + if ((rv = apr_file_open(&cfg->fd, fname, + APR_WRITE | APR_APPEND | APR_CREATE, + APR_OS_DEFAULT, p)) != APR_SUCCESS) { + ap_log_error(APLOG_MARK, APLOG_ERR, rv, s, APLOGNO(00651) + "could not open forensic log file %s.", fname); + return 0; + } + } + + return 1; +} + +static int log_init(apr_pool_t *pc, apr_pool_t *p, apr_pool_t *pt, + server_rec *s) +{ + for ( ; s ; s = s->next) { + if (!open_log(s, p)) { + return HTTP_INTERNAL_SERVER_ERROR; + } + } + + return OK; +} + + +/* e is the first _invalid_ location in q + N.B. returns the terminating NUL. + */ +static char *log_escape(char *q, const char *e, const char *p) +{ + for ( ; *p ; ++p) { + ap_assert(q < e); + if (test_char_table[*(unsigned char *)p]&T_ESCAPE_FORENSIC) { + ap_assert(q+2 < e); + *q++ = '%'; + ap_bin2hex(p, 1, q); + q += 2; + } + else + *q++ = *p; + } + ap_assert(q < e); + *q = '\0'; + + return q; +} + +typedef struct hlog { + char *log; + char *pos; + char *end; + apr_pool_t *p; + apr_size_t count; +} hlog; + +static int count_string(const char *p) +{ + int n; + + for (n = 0 ; *p ; ++p, ++n) + if (test_char_table[*(unsigned char *)p]&T_ESCAPE_FORENSIC) + n += 2; + return n; +} + +static int count_headers(void *h_, const char *key, const char *value) +{ + hlog *h = h_; + + h->count += count_string(key)+count_string(value)+2; + + return 1; +} + +static int log_headers(void *h_, const char *key, const char *value) +{ + hlog *h = h_; + + /* note that we don't have to check h->pos here, coz its been done + for us by log_escape */ + *h->pos++ = '|'; + h->pos = log_escape(h->pos, h->end, key); + *h->pos++ = ':'; + h->pos = log_escape(h->pos, h->end, value); + + return 1; +} + +static int log_before(request_rec *r) +{ + fcfg *cfg = ap_get_module_config(r->server->module_config, + &log_forensic_module); + const char *id; + hlog h; + apr_size_t n; + apr_status_t rv; + + if (!cfg->fd || r->prev) { + return DECLINED; + } + + if (!(id = apr_table_get(r->subprocess_env, "UNIQUE_ID"))) { + /* we make the assumption that we can't go through all the PIDs in + under 1 second */ + id = apr_psprintf(r->pool, "%" APR_PID_T_FMT ":%lx:%x", getpid(), + time(NULL), apr_atomic_inc32(&next_id)); + } + ap_set_module_config(r->request_config, &log_forensic_module, (char *)id); + + h.p = r->pool; + h.count = 0; + + apr_table_do(count_headers, &h, r->headers_in, NULL); + + h.count += 1+strlen(id)+1+count_string(r->the_request)+1+1; + h.log = apr_palloc(r->pool, h.count); + h.pos = h.log; + h.end = h.log+h.count; + + *h.pos++ = '+'; + strcpy(h.pos, id); + h.pos += strlen(h.pos); + *h.pos++ = '|'; + h.pos = log_escape(h.pos, h.end, r->the_request); + + apr_table_do(log_headers, &h, r->headers_in, NULL); + + ap_assert(h.pos < h.end); + *h.pos++ = '\n'; + + n = h.count-1; + rv = apr_file_write(cfg->fd, h.log, &n); + ap_assert(rv == APR_SUCCESS && n == h.count-1); + + apr_table_setn(r->notes, "forensic-id", id); + + return OK; +} + +static int log_after(request_rec *r) +{ + fcfg *cfg = ap_get_module_config(r->server->module_config, + &log_forensic_module); + const char *id = ap_get_module_config(r->request_config, + &log_forensic_module); + char *s; + apr_size_t l, n; + apr_status_t rv; + + if (!cfg->fd || id == NULL) { + return DECLINED; + } + + s = apr_pstrcat(r->pool, "-", id, "\n", NULL); + l = n = strlen(s); + rv = apr_file_write(cfg->fd, s, &n); + ap_assert(rv == APR_SUCCESS && n == l); + + return OK; +} + +static const char *set_forensic_log(cmd_parms *cmd, void *dummy, const char *fn) +{ + fcfg *cfg = ap_get_module_config(cmd->server->module_config, + &log_forensic_module); + + cfg->logname = fn; + return NULL; +} + +static const command_rec forensic_log_cmds[] = +{ + AP_INIT_TAKE1("ForensicLog", set_forensic_log, NULL, RSRC_CONF, + "the filename of the forensic log"), + { NULL } +}; + +static void register_hooks(apr_pool_t *p) +{ + static const char * const pre[] = { "mod_unique_id.c", NULL }; + + ap_hook_open_logs(log_init,NULL,NULL,APR_HOOK_MIDDLE); + ap_hook_post_read_request(log_before,pre,NULL,APR_HOOK_REALLY_FIRST); + ap_hook_log_transaction(log_after,NULL,NULL,APR_HOOK_REALLY_LAST); +} + +AP_DECLARE_MODULE(log_forensic) = +{ + STANDARD20_MODULE_STUFF, + NULL, /* create per-dir config */ + NULL, /* merge per-dir config */ + make_forensic_log_scfg, /* server config */ + merge_forensic_log_scfg, /* merge server config */ + forensic_log_cmds, /* command apr_table_t */ + register_hooks /* register hooks */ +}; |