/* 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, "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, "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++ = '%'; sprintf(q, "%02x", *(unsigned char *)p); 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) { 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); } module AP_MODULE_DECLARE_DATA log_forensic_module = { 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 */ };
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