Mercurial > hg > nginx
view src/core/ngx_syslog.c @ 9300:5be23505292b
SSI: fixed incorrect or duplicate stub output.
Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set
if there are data in the first buffer sent in the subrequest. As a
result, following the change mentioned this flag cannot be used to
prevent duplicate ngx_http_ssi_stub_output() calls, since it is not
set if there was already some output, but the first buffer was empty.
Still, when there are multiple subrequests, even an empty subrequest
response might be delayed by the postpone filter, leading to a second
call of ngx_http_ssi_stub_output() during finalization from
ngx_http_writer() the subreqest buffers are released by the postpone
filter. Since r->request_output is not set after the first call, this
resulted in duplicate stub output.
Additionally, checking only the first buffer might be wrong in some
unusual cases. For example, the first buffer might be empty if
$r->flush() is called before printing any data in the embedded Perl
module.
Depending on the postpone_output value and corresponding sizes, this
issue can result in either duplicate or unexpected stub output, or
"zero size buf in writer" alerts.
Following 8124:f5515e727656 (1.23.4), it became slightly easier to
reproduce the issue, as empty static files and empty cache items now
result in a response with an empty buffer. Before the change, an empty
proxied response can be used to reproduce the issue.
Fix is check all buffers and set r->request_output if any non-empty
buffers are sent. This ensures that all unusual cases of non-empty
responses are covered, and also that r->request_output will be set
after the first stub output, preventing duplicate output.
Reported by Jan Gassen.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 04 Jul 2024 17:41:28 +0300 |
parents | c769217b4a5c |
children |
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/* * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #define NGX_SYSLOG_MAX_STR \ NGX_MAX_ERROR_STR + sizeof("<255>Jan 01 00:00:00 ") - 1 \ + (NGX_MAXHOSTNAMELEN - 1) + 1 /* space */ \ + 32 /* tag */ + 2 /* colon, space */ static char *ngx_syslog_parse_args(ngx_conf_t *cf, ngx_syslog_peer_t *peer); static ngx_int_t ngx_syslog_init_peer(ngx_syslog_peer_t *peer); static void ngx_syslog_cleanup(void *data); static u_char *ngx_syslog_log_error(ngx_log_t *log, u_char *buf, size_t len); static char *facilities[] = { "kern", "user", "mail", "daemon", "auth", "intern", "lpr", "news", "uucp", "clock", "authpriv", "ftp", "ntp", "audit", "alert", "cron", "local0", "local1", "local2", "local3", "local4", "local5", "local6", "local7", NULL }; /* note 'error/warn' like in nginx.conf, not 'err/warning' */ static char *severities[] = { "emerg", "alert", "crit", "error", "warn", "notice", "info", "debug", NULL }; static ngx_log_t ngx_syslog_dummy_log; static ngx_event_t ngx_syslog_dummy_event; char * ngx_syslog_process_conf(ngx_conf_t *cf, ngx_syslog_peer_t *peer) { ngx_pool_cleanup_t *cln; peer->facility = NGX_CONF_UNSET_UINT; peer->severity = NGX_CONF_UNSET_UINT; if (ngx_syslog_parse_args(cf, peer) != NGX_CONF_OK) { return NGX_CONF_ERROR; } if (peer->server.sockaddr == NULL) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "no syslog server specified"); return NGX_CONF_ERROR; } if (peer->facility == NGX_CONF_UNSET_UINT) { peer->facility = 23; /* local7 */ } if (peer->severity == NGX_CONF_UNSET_UINT) { peer->severity = 6; /* info */ } if (peer->tag.data == NULL) { ngx_str_set(&peer->tag, "nginx"); } peer->hostname = &cf->cycle->hostname; peer->logp = &cf->cycle->new_log; peer->conn.fd = (ngx_socket_t) -1; peer->conn.read = &ngx_syslog_dummy_event; peer->conn.write = &ngx_syslog_dummy_event; ngx_syslog_dummy_event.log = &ngx_syslog_dummy_log; cln = ngx_pool_cleanup_add(cf->pool, 0); if (cln == NULL) { return NGX_CONF_ERROR; } cln->data = peer; cln->handler = ngx_syslog_cleanup; return NGX_CONF_OK; } static char * ngx_syslog_parse_args(ngx_conf_t *cf, ngx_syslog_peer_t *peer) { u_char *p, *comma, c; size_t len; ngx_str_t *value; ngx_url_t u; ngx_uint_t i; value = cf->args->elts; p = value[1].data + sizeof("syslog:") - 1; for ( ;; ) { comma = (u_char *) ngx_strchr(p, ','); if (comma != NULL) { len = comma - p; *comma = '\0'; } else { len = value[1].data + value[1].len - p; } if (ngx_strncmp(p, "server=", 7) == 0) { if (peer->server.sockaddr != NULL) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "duplicate syslog \"server\""); return NGX_CONF_ERROR; } ngx_memzero(&u, sizeof(ngx_url_t)); u.url.data = p + 7; u.url.len = len - 7; u.default_port = 514; if (ngx_parse_url(cf->pool, &u) != NGX_OK) { if (u.err) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%s in syslog server \"%V\"", u.err, &u.url); } return NGX_CONF_ERROR; } peer->server = u.addrs[0]; } else if (ngx_strncmp(p, "facility=", 9) == 0) { if (peer->facility != NGX_CONF_UNSET_UINT) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "duplicate syslog \"facility\""); return NGX_CONF_ERROR; } for (i = 0; facilities[i] != NULL; i++) { if (ngx_strcmp(p + 9, facilities[i]) == 0) { peer->facility = i; goto next; } } ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "unknown syslog facility \"%s\"", p + 9); return NGX_CONF_ERROR; } else if (ngx_strncmp(p, "severity=", 9) == 0) { if (peer->severity != NGX_CONF_UNSET_UINT) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "duplicate syslog \"severity\""); return NGX_CONF_ERROR; } for (i = 0; severities[i] != NULL; i++) { if (ngx_strcmp(p + 9, severities[i]) == 0) { peer->severity = i; goto next; } } ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "unknown syslog severity \"%s\"", p + 9); return NGX_CONF_ERROR; } else if (ngx_strncmp(p, "tag=", 4) == 0) { if (peer->tag.data != NULL) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "duplicate syslog \"tag\""); return NGX_CONF_ERROR; } /* * RFC 3164: the TAG is a string of ABNF alphanumeric characters * that MUST NOT exceed 32 characters. */ if (len - 4 > 32) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "syslog tag length exceeds 32"); return NGX_CONF_ERROR; } for (i = 4; i < len; i++) { c = ngx_tolower(p[i]); if (c < '0' || (c > '9' && c < 'a' && c != '_') || c > 'z') { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "syslog \"tag\" only allows " "alphanumeric characters " "and underscore"); return NGX_CONF_ERROR; } } peer->tag.data = p + 4; peer->tag.len = len - 4; } else if (len == 10 && ngx_strncmp(p, "nohostname", 10) == 0) { peer->nohostname = 1; } else { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "unknown syslog parameter \"%s\"", p); return NGX_CONF_ERROR; } next: if (comma == NULL) { break; } p = comma + 1; } return NGX_CONF_OK; } u_char * ngx_syslog_add_header(ngx_syslog_peer_t *peer, u_char *buf) { ngx_uint_t pri; pri = peer->facility * 8 + peer->severity; if (peer->nohostname) { return ngx_sprintf(buf, "<%ui>%V %V: ", pri, &ngx_cached_syslog_time, &peer->tag); } return ngx_sprintf(buf, "<%ui>%V %V %V: ", pri, &ngx_cached_syslog_time, peer->hostname, &peer->tag); } void ngx_syslog_writer(ngx_log_t *log, ngx_uint_t level, u_char *buf, size_t len) { u_char *p, msg[NGX_SYSLOG_MAX_STR]; ngx_uint_t head_len; ngx_syslog_peer_t *peer; peer = log->wdata; if (peer->busy) { return; } peer->busy = 1; peer->severity = level - 1; p = ngx_syslog_add_header(peer, msg); head_len = p - msg; len -= NGX_LINEFEED_SIZE; if (len > NGX_SYSLOG_MAX_STR - head_len) { len = NGX_SYSLOG_MAX_STR - head_len; } p = ngx_snprintf(p, len, "%s", buf); (void) ngx_syslog_send(peer, msg, p - msg); peer->busy = 0; } ssize_t ngx_syslog_send(ngx_syslog_peer_t *peer, u_char *buf, size_t len) { ssize_t n; if (peer->log.handler == NULL) { peer->log = *peer->logp; peer->log.handler = ngx_syslog_log_error; peer->log.data = peer; peer->log.action = "logging to syslog"; } if (peer->conn.fd == (ngx_socket_t) -1) { if (ngx_syslog_init_peer(peer) != NGX_OK) { return NGX_ERROR; } } if (ngx_time() == peer->error_log_time) { peer->conn.log_error = NGX_ERROR_DEBUG; } if (ngx_send) { n = ngx_send(&peer->conn, buf, len); } else { /* event module has not yet set ngx_io */ n = ngx_os_io.send(&peer->conn, buf, len); } if (n == NGX_ERROR && peer->conn.log_error != NGX_ERROR_DEBUG) { if (ngx_close_socket(peer->conn.fd) == -1) { ngx_log_error(NGX_LOG_ALERT, &peer->log, ngx_socket_errno, ngx_close_socket_n " failed"); } peer->conn.fd = (ngx_socket_t) -1; peer->error_log_time = ngx_time(); } else if ((size_t) n != len && peer->conn.log_error != NGX_ERROR_DEBUG) { ngx_log_error(NGX_LOG_CRIT, &peer->log, 0, "send() incomplete"); peer->error_log_time = ngx_time(); } peer->conn.log_error = NGX_ERROR_ERR; return n; } static ngx_int_t ngx_syslog_init_peer(ngx_syslog_peer_t *peer) { ngx_socket_t fd; if (ngx_time() == peer->connect_error_time) { return NGX_ERROR; } fd = ngx_socket(peer->server.sockaddr->sa_family, SOCK_DGRAM, 0); if (fd == (ngx_socket_t) -1) { ngx_log_error(NGX_LOG_ALERT, &peer->log, ngx_socket_errno, ngx_socket_n " failed"); peer->connect_error_time = ngx_time(); return NGX_ERROR; } if (ngx_nonblocking(fd) == -1) { ngx_log_error(NGX_LOG_ALERT, &peer->log, ngx_socket_errno, ngx_nonblocking_n " failed"); goto failed; } if (connect(fd, peer->server.sockaddr, peer->server.socklen) == -1) { ngx_log_error(NGX_LOG_CRIT, &peer->log, ngx_socket_errno, "connect() failed"); goto failed; } peer->conn.fd = fd; peer->conn.log = &peer->log; peer->conn.log_error = NGX_ERROR_ERR; /* UDP sockets are always ready to write */ peer->conn.write->ready = 1; return NGX_OK; failed: peer->connect_error_time = ngx_time(); if (ngx_close_socket(fd) == -1) { ngx_log_error(NGX_LOG_ALERT, &peer->log, ngx_socket_errno, ngx_close_socket_n " failed"); } return NGX_ERROR; } static void ngx_syslog_cleanup(void *data) { ngx_syslog_peer_t *peer = data; /* prevents further use of this peer */ peer->busy = 1; if (peer->conn.fd == (ngx_socket_t) -1) { return; } if (ngx_close_socket(peer->conn.fd) == -1) { ngx_log_error(NGX_LOG_ALERT, &peer->log, ngx_socket_errno, ngx_close_socket_n " failed"); } } static u_char * ngx_syslog_log_error(ngx_log_t *log, u_char *buf, size_t len) { u_char *p; ngx_syslog_peer_t *peer; p = buf; if (log->action) { p = ngx_snprintf(buf, len, " while %s", log->action); len -= p - buf; } peer = log->data; if (peer) { p = ngx_snprintf(p, len, ", server: %V", &peer->server.name); } return p; }