Mercurial > hg > nginx
view src/os/win32/ngx_process.c @ 9300:5be23505292b default tip
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 | 7640d6c213e1 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> int ngx_argc; char **ngx_argv; char **ngx_os_argv; ngx_int_t ngx_last_process; ngx_process_t ngx_processes[NGX_MAX_PROCESSES]; ngx_pid_t ngx_spawn_process(ngx_cycle_t *cycle, char *name, ngx_int_t respawn) { u_long rc, n, code; ngx_int_t s; ngx_pid_t pid; ngx_exec_ctx_t ctx; HANDLE events[2]; char file[MAX_PATH + 1]; if (respawn >= 0) { s = respawn; } else { for (s = 0; s < ngx_last_process; s++) { if (ngx_processes[s].handle == NULL) { break; } } if (s == NGX_MAX_PROCESSES) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "no more than %d processes can be spawned", NGX_MAX_PROCESSES); return NGX_INVALID_PID; } } n = GetModuleFileName(NULL, file, MAX_PATH); if (n == 0) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "GetModuleFileName() failed"); return NGX_INVALID_PID; } file[n] = '\0'; ngx_log_debug1(NGX_LOG_DEBUG_CORE, cycle->log, 0, "GetModuleFileName: \"%s\"", file); ctx.path = file; ctx.name = name; ctx.args = GetCommandLine(); ctx.argv = NULL; ctx.envp = NULL; pid = ngx_execute(cycle, &ctx); if (pid == NGX_INVALID_PID) { return pid; } ngx_memzero(&ngx_processes[s], sizeof(ngx_process_t)); ngx_processes[s].handle = ctx.child; ngx_processes[s].pid = pid; ngx_processes[s].name = name; ngx_sprintf(ngx_processes[s].term_event, "ngx_%s_term_%P%Z", name, pid); ngx_sprintf(ngx_processes[s].quit_event, "ngx_%s_quit_%P%Z", name, pid); ngx_sprintf(ngx_processes[s].reopen_event, "ngx_%s_reopen_%P%Z", name, pid); events[0] = ngx_master_process_event; events[1] = ctx.child; rc = WaitForMultipleObjects(2, events, 0, 5000); ngx_time_update(); ngx_log_debug1(NGX_LOG_DEBUG_CORE, cycle->log, 0, "WaitForMultipleObjects: %ul", rc); switch (rc) { case WAIT_OBJECT_0: ngx_processes[s].term = OpenEvent(EVENT_MODIFY_STATE, 0, (char *) ngx_processes[s].term_event); if (ngx_processes[s].term == NULL) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "OpenEvent(\"%s\") failed", ngx_processes[s].term_event); goto failed; } ngx_processes[s].quit = OpenEvent(EVENT_MODIFY_STATE, 0, (char *) ngx_processes[s].quit_event); if (ngx_processes[s].quit == NULL) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "OpenEvent(\"%s\") failed", ngx_processes[s].quit_event); goto failed; } ngx_processes[s].reopen = OpenEvent(EVENT_MODIFY_STATE, 0, (char *) ngx_processes[s].reopen_event); if (ngx_processes[s].reopen == NULL) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "OpenEvent(\"%s\") failed", ngx_processes[s].reopen_event); goto failed; } if (ResetEvent(ngx_master_process_event) == 0) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "ResetEvent(\"%s\") failed", ngx_master_process_event_name); goto failed; } break; case WAIT_OBJECT_0 + 1: if (GetExitCodeProcess(ctx.child, &code) == 0) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "GetExitCodeProcess(%P) failed", pid); } ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "%s process %P exited with code %Xl", name, pid, code); goto failed; case WAIT_TIMEOUT: ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "the event \"%s\" was not signaled for 5s", ngx_master_process_event_name); goto failed; case WAIT_FAILED: ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "WaitForSingleObject(\"%s\") failed", ngx_master_process_event_name); goto failed; } if (respawn >= 0) { return pid; } switch (respawn) { case NGX_PROCESS_RESPAWN: ngx_processes[s].just_spawn = 0; break; case NGX_PROCESS_JUST_RESPAWN: ngx_processes[s].just_spawn = 1; break; } if (s == ngx_last_process) { ngx_last_process++; } return pid; failed: if (ngx_processes[s].reopen) { ngx_close_handle(ngx_processes[s].reopen); } if (ngx_processes[s].quit) { ngx_close_handle(ngx_processes[s].quit); } if (ngx_processes[s].term) { ngx_close_handle(ngx_processes[s].term); } TerminateProcess(ngx_processes[s].handle, 2); if (ngx_processes[s].handle) { ngx_close_handle(ngx_processes[s].handle); ngx_processes[s].handle = NULL; } return NGX_INVALID_PID; } ngx_pid_t ngx_execute(ngx_cycle_t *cycle, ngx_exec_ctx_t *ctx) { STARTUPINFO si; PROCESS_INFORMATION pi; ngx_memzero(&si, sizeof(STARTUPINFO)); si.cb = sizeof(STARTUPINFO); ngx_memzero(&pi, sizeof(PROCESS_INFORMATION)); if (CreateProcess(ctx->path, ctx->args, NULL, NULL, 0, CREATE_NO_WINDOW, NULL, NULL, &si, &pi) == 0) { ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_errno, "CreateProcess(\"%s\") failed", ngx_argv[0]); return 0; } ctx->child = pi.hProcess; if (CloseHandle(pi.hThread) == 0) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "CloseHandle(pi.hThread) failed"); } ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "start %s process %P", ctx->name, pi.dwProcessId); return pi.dwProcessId; }