/* * $Id: unlinkd.cc,v 1.64 2007/04/30 16:56:09 wessels Exp $ * * DEBUG: section 2 Unlink Daemon * AUTHOR: Duane Wessels * * SQUID Web Proxy Cache http://www.squid-cache.org/ * ---------------------------------------------------------- * * Squid is the result of efforts by numerous individuals from * the Internet community; see the CONTRIBUTORS file for full * details. Many organizations have provided support for Squid's * development; see the SPONSORS file for full details. Squid is * Copyrighted (C) 2001 by the Regents of the University of * California; see the COPYRIGHT file for full details. Squid * incorporates software developed and/or copyrighted by other * sources; see the CREDITS file for full details. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. * */ #include "squid.h" #include "SquidTime.h" #include "fde.h" #include "xusleep.h" /* This code gets linked to Squid */ static int unlinkd_wfd = -1; static int unlinkd_rfd = -1; static void * hIpc; static pid_t pid; #define UNLINKD_QUEUE_LIMIT 20 void unlinkdUnlink(const char *path) { char buf[MAXPATHLEN]; int l; int x; static int queuelen = 0; if (unlinkd_wfd < 0) { debug_trap("unlinkdUnlink: unlinkd_wfd < 0"); safeunlink(path, 0); return; } /* * If the queue length is greater than our limit, then we pause * for a small amount of time, hoping that unlinkd has some * feedback for us. Maybe it just needs a slice of the CPU's * time. */ if (queuelen >= UNLINKD_QUEUE_LIMIT) { #if defined(USE_EPOLL) || defined(USE_KQUEUE) /* * DPW 2007-04-23 * We can't use fd_set when using epoll() or kqueue(). In * these cases we block for 10 ms. */ xusleep(10000); #else /* * DPW 2007-04-23 * When we can use select, block for up to 100 ms. */ struct timeval to; fd_set R; FD_ZERO(&R); FD_SET(unlinkd_rfd, &R); to.tv_sec = 0; to.tv_usec = 100000; select(unlinkd_rfd + 1, &R, NULL, NULL, &to); #endif } /* * If there is at least one outstanding unlink request, then * try to read a response. If there's nothing to read we'll * get an EWOULDBLOCK or whatever. If we get a response, then * decrement the queue size by the number of newlines read. */ if (queuelen > 0) { int x; int i; char rbuf[512]; x = read(unlinkd_rfd, rbuf, 511); if (x > 0) { rbuf[x] = '\0'; for (i = 0; i < x; i++) if ('\n' == rbuf[i]) queuelen--; assert(queuelen >= 0); } } l = strlen(path); assert(l < MAXPATHLEN); xstrncpy(buf, path, MAXPATHLEN); buf[l++] = '\n'; x = write(unlinkd_wfd, buf, l); if (x < 0) { debugs(2, 1, "unlinkdUnlink: write FD " << unlinkd_wfd << " failed: " << xstrerror()); safeunlink(path, 0); return; } else if (x != l) { debugs(2, 1, "unlinkdUnlink: FD " << unlinkd_wfd << " only wrote " << x << " of " << l << " bytes"); safeunlink(path, 0); return; } statCounter.unlink.requests++; /* * Increment this syscalls counter here, even though the syscall * is executed by the helper process. We try to be consistent * in counting unlink operations. */ statCounter.syscalls.disk.unlinks++; queuelen++; } void unlinkdClose(void) #ifdef _SQUID_MSWIN_ { if (unlinkd_wfd > -1) { debugs(2, 1, "Closing unlinkd pipe on FD " << unlinkd_wfd); shutdown(unlinkd_wfd, SD_BOTH); comm_close(unlinkd_wfd); if (unlinkd_wfd != unlinkd_rfd) comm_close(unlinkd_rfd); unlinkd_wfd = -1; unlinkd_rfd = -1; } else debugs(2, 0, "unlinkdClose: WARNING: unlinkd_wfd is " << unlinkd_wfd); if (hIpc) { if (WaitForSingleObject(hIpc, 5000) != WAIT_OBJECT_0) { getCurrentTime(); debugs(2, 1, "unlinkdClose: WARNING: (unlinkd," << pid << "d) didn't exit in 5 seconds"); } CloseHandle(hIpc); } } #else { if (unlinkd_wfd < 0) return; debugs(2, 1, "Closing unlinkd pipe on FD " << unlinkd_wfd); file_close(unlinkd_wfd); if (unlinkd_wfd != unlinkd_rfd) file_close(unlinkd_rfd); unlinkd_wfd = -1; unlinkd_rfd = -1; } #endif void unlinkdInit(void) { const char *args[2]; args[0] = "(unlinkd)"; args[1] = NULL; pid = ipcCreate( #if USE_POLL && defined(_SQUID_OSF_) /* pipes and poll() don't get along on DUNIX -DW */ IPC_STREAM, #elif defined(_SQUID_MSWIN_) /* select() will fail on a pipe */ IPC_TCP_SOCKET, #else /* We currently need to use FIFO.. see below */ IPC_FIFO, #endif Config.Program.unlinkd, args, "unlinkd", &unlinkd_rfd, &unlinkd_wfd, &hIpc); if (pid < 0) fatal("Failed to create unlinkd subprocess"); xusleep(250000); fd_note(unlinkd_wfd, "squid -> unlinkd"); fd_note(unlinkd_rfd, "unlinkd -> squid"); commSetTimeout(unlinkd_rfd, -1, NULL, NULL); commSetTimeout(unlinkd_wfd, -1, NULL, NULL); /* * unlinkd_rfd should already be non-blocking because of * ipcCreate. We change unlinkd_wfd to blocking mode because * we never want to lose an unlink request, and we don't have * code to retry if we get EWOULDBLOCK. Unfortunately, we can * do this only for the IPC_FIFO case. */ assert(fd_table[unlinkd_rfd].flags.nonblocking); if (FD_PIPE == fd_table[unlinkd_wfd].type) commUnsetNonBlocking(unlinkd_wfd); debugs(2, 1, "Unlinkd pipe opened on FD " << unlinkd_wfd); #ifdef _SQUID_MSWIN_ debugs(2, 4, "Unlinkd handle: 0x" << std::hex << hIpc << std::dec << ", PID: " << pid); #endif }