/* * $Id: store_client.c,v 1.98.2.1 2001/01/12 00:51:53 wessels Exp $ * * DEBUG: section 20 Storage Manager Client-Side Interface * 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" /* * NOTE: 'Header' refers to the swapfile metadata header. * 'Body' refers to the swapfile body, which is the full * HTTP reply (including HTTP headers and body). */ static STRCB storeClientReadBody; static STRCB storeClientReadHeader; static void storeClientCopy2(StoreEntry * e, store_client * sc); static void storeClientCopy3(StoreEntry * e, store_client * sc); static void storeClientFileRead(store_client * sc); static EVH storeClientCopyEvent; static store_client_t storeClientType(StoreEntry *); static int CheckQuickAbort2(StoreEntry * entry); static void CheckQuickAbort(StoreEntry * entry); /* check if there is any client waiting for this object at all */ /* return 1 if there is at least one client */ int storeClientWaiting(const StoreEntry * e) { MemObject *mem = e->mem_obj; dlink_node *node; store_client *sc; for (node = mem->clients.head; node; node = node->next) { sc = node->data; if (sc->callback_data != NULL) return 1; } return 0; } #if STORE_CLIENT_LIST_DEBUG store_client * storeClientListSearch(const MemObject * mem, void *data) { dlink_node *node; store_client *sc = NULL; for (node = mem->clients.head; node; node = node->next) { sc = node->data; if (sc->callback_data == data) return sc; } return NULL; } #endif static store_client_t storeClientType(StoreEntry * e) { MemObject *mem = e->mem_obj; if (mem->inmem_lo) return STORE_DISK_CLIENT; if (EBIT_TEST(e->flags, ENTRY_ABORTED)) { /* I don't think we should be adding clients to aborted entries */ debug(20, 1) ("storeClientType: adding to ENTRY_ABORTED entry\n"); return STORE_MEM_CLIENT; } if (e->store_status == STORE_OK) { if (mem->inmem_lo == 0 && mem->inmem_hi > 0) return STORE_MEM_CLIENT; else return STORE_DISK_CLIENT; } /* here and past, entry is STORE_PENDING */ /* * If this is the first client, let it be the mem client */ else if (mem->nclients == 1) return STORE_MEM_CLIENT; /* * If there is no disk file to open yet, we must make this a * mem client. If we can't open the swapin file before writing * to the client, there is no guarantee that we will be able * to open it later when we really need it. */ else if (e->swap_status == SWAPOUT_NONE) return STORE_MEM_CLIENT; /* * otherwise, make subsequent clients read from disk so they * can not delay the first, and vice-versa. */ else return STORE_DISK_CLIENT; } /* add client with fd to client list */ store_client * storeClientListAdd(StoreEntry * e, void *data) { MemObject *mem = e->mem_obj; store_client *sc; assert(mem); #if STORE_CLIENT_LIST_DEBUG if (storeClientListSearch(mem, data) != NULL) assert(1 == 0); /* XXX die! */ #endif e->refcount++; mem->nclients++; sc = memAllocate(MEM_STORE_CLIENT); cbdataAdd(sc, memFree, MEM_STORE_CLIENT); /* sc is callback_data for file_read */ cbdataLock(data); /* locked while we point to it */ sc->callback_data = data; sc->seen_offset = 0; sc->copy_offset = 0; sc->flags.disk_io_pending = 0; sc->entry = e; sc->type = storeClientType(e); if (sc->type == STORE_DISK_CLIENT) /* assert we'll be able to get the data we want */ /* maybe we should open swapin_fd here */ assert(e->swap_filen > -1 || storeSwapOutAble(e)); dlinkAdd(sc, &sc->node, &mem->clients); #if DELAY_POOLS sc->delay_id = 0; #endif return sc; } static void storeClientCallback(store_client * sc, ssize_t sz) { STCB *callback = sc->callback; char *buf = sc->copy_buf; assert(sc->callback); sc->callback = NULL; sc->copy_buf = NULL; if (cbdataValid(sc->callback_data)) callback(sc->callback_data, buf, sz); } static void storeClientCopyEvent(void *data) { store_client *sc = data; debug(20, 3) ("storeClientCopyEvent: Running\n"); sc->flags.copy_event_pending = 0; if (!sc->callback) return; storeClientCopy2(sc->entry, sc); } /* copy bytes requested by the client */ void storeClientCopy(store_client * sc, StoreEntry * e, off_t seen_offset, off_t copy_offset, size_t size, char *buf, STCB * callback, void *data) { assert(!EBIT_TEST(e->flags, ENTRY_ABORTED)); debug(20, 3) ("storeClientCopy: %s, seen %d, want %d, size %d, cb %p, cbdata %p\n", storeKeyText(e->hash.key), (int) seen_offset, (int) copy_offset, (int) size, callback, data); assert(sc != NULL); #if STORE_CLIENT_LIST_DEBUG assert(sc == storeClientListSearch(e->mem_obj, data)); #endif assert(sc->callback == NULL); assert(sc->entry == e); sc->copy_offset = copy_offset; sc->seen_offset = seen_offset; sc->callback = callback; sc->copy_buf = buf; sc->copy_size = size; sc->copy_offset = copy_offset; storeClientCopy2(e, sc); } /* * This function is used below to decide if we have any more data to * send to the client. If the store_status is STORE_PENDING, then we * do have more data to send. If its STORE_OK, then * we continue checking. If the object length is negative, then we * don't know the real length and must open the swap file to find out. * If the length is >= 0, then we compare it to the requested copy * offset. */ static int storeClientNoMoreToSend(StoreEntry * e, store_client * sc) { ssize_t len; if (e->store_status == STORE_PENDING) return 0; if ((len = objectLen(e)) < 0) return 0; if (sc->copy_offset < len) return 0; return 1; } static void storeClientCopy2(StoreEntry * e, store_client * sc) { if (sc->flags.copy_event_pending) return; if (EBIT_TEST(e->flags, ENTRY_FWD_HDR_WAIT)) { debug(20, 5) ("storeClientCopy2: returning because ENTRY_FWD_HDR_WAIT set\n"); return; } if (sc->flags.store_copying) { sc->flags.copy_event_pending = 1; debug(20, 3) ("storeClientCopy2: Queueing storeClientCopyEvent()\n"); eventAdd("storeClientCopyEvent", storeClientCopyEvent, sc, 0.0, 0); return; } cbdataLock(sc); /* ick, prevent sc from getting freed */ sc->flags.store_copying = 1; debug(20, 3) ("storeClientCopy2: %s\n", storeKeyText(e->hash.key)); assert(sc->callback != NULL); /* * We used to check for ENTRY_ABORTED here. But there were some * problems. For example, we might have a slow client (or two) and * the server-side is reading far ahead and swapping to disk. Even * if the server-side aborts, we want to give the client(s) * everything we got before the abort condition occurred. */ storeClientCopy3(e, sc); sc->flags.store_copying = 0; cbdataUnlock(sc); /* ick, allow sc to be freed */ } static void storeClientCopy3(StoreEntry * e, store_client * sc) { MemObject *mem = e->mem_obj; size_t sz; if (storeClientNoMoreToSend(e, sc)) { /* There is no more to send! */ storeClientCallback(sc, 0); return; } if (e->store_status == STORE_PENDING && sc->seen_offset >= mem->inmem_hi) { /* client has already seen this, wait for more */ debug(20, 3) ("storeClientCopy3: Waiting for more\n"); return; } /* * Slight weirdness here. We open a swapin file for any * STORE_DISK_CLIENT, even if we can copy the requested chunk * from memory in the next block. We must try to open the * swapin file before sending any data to the client side. If * we postpone the open, and then can not open the file later * on, the client loses big time. Its transfer just gets cut * off. Better to open it early (while the client side handler * is clientCacheHit) so that we can fall back to a cache miss * if needed. */ if (STORE_DISK_CLIENT == sc->type && NULL == sc->swapin_sio) { debug(20, 3) ("storeClientCopy3: Need to open swap in file\n"); /* gotta open the swapin file */ if (storeTooManyDiskFilesOpen()) { /* yuck -- this causes a TCP_SWAPFAIL_MISS on the client side */ storeClientCallback(sc, -1); return; } else if (!sc->flags.disk_io_pending) { /* Don't set store_io_pending here */ storeSwapInStart(sc); if (NULL == sc->swapin_sio) { storeClientCallback(sc, -1); return; } /* * If the open succeeds we either copy from memory, or * schedule a disk read in the next block. */ } else { debug(20, 1) ("WARNING: Averted multiple fd operation (1)\n"); return; } } if (sc->copy_offset >= mem->inmem_lo && sc->copy_offset < mem->inmem_hi) { /* What the client wants is in memory */ debug(20, 3) ("storeClientCopy3: Copying from memory\n"); sz = stmemCopy(&mem->data_hdr, sc->copy_offset, sc->copy_buf, sc->copy_size); storeClientCallback(sc, sz); return; } /* What the client wants is not in memory. Schedule a disk read */ assert(STORE_DISK_CLIENT == sc->type); assert(!sc->flags.disk_io_pending); debug(20, 3) ("storeClientCopy3: reading from STORE\n"); storeClientFileRead(sc); } static void storeClientFileRead(store_client * sc) { MemObject *mem = sc->entry->mem_obj; assert(sc->callback != NULL); assert(!sc->flags.disk_io_pending); sc->flags.disk_io_pending = 1; if (mem->swap_hdr_sz == 0) { storeRead(sc->swapin_sio, sc->copy_buf, sc->copy_size, 0, storeClientReadHeader, sc); } else { if (sc->entry->swap_status == SWAPOUT_WRITING) assert(storeOffset(mem->swapout.sio) > sc->copy_offset + mem->swap_hdr_sz); storeRead(sc->swapin_sio, sc->copy_buf, sc->copy_size, sc->copy_offset + mem->swap_hdr_sz, storeClientReadBody, sc); } } static void storeClientReadBody(void *data, const char *buf, ssize_t len) { store_client *sc = data; MemObject *mem = sc->entry->mem_obj; assert(sc->flags.disk_io_pending); sc->flags.disk_io_pending = 0; assert(sc->callback != NULL); debug(20, 3) ("storeClientReadBody: len %d\n", len); if (sc->copy_offset == 0 && len > 0 && mem->reply->sline.status == 0) httpReplyParse(mem->reply, sc->copy_buf, headersEnd(sc->copy_buf, len)); storeClientCallback(sc, len); } static void storeClientReadHeader(void *data, const char *buf, ssize_t len) { static int md5_mismatches = 0; store_client *sc = data; StoreEntry *e = sc->entry; MemObject *mem = e->mem_obj; int swap_hdr_sz = 0; size_t body_sz; size_t copy_sz; tlv *tlv_list; tlv *t; int swap_object_ok = 1; assert(sc->flags.disk_io_pending); sc->flags.disk_io_pending = 0; assert(sc->callback != NULL); debug(20, 3) ("storeClientReadHeader: len %d\n", len); if (len < 0) { debug(20, 3) ("storeClientReadHeader: %s\n", xstrerror()); storeClientCallback(sc, len); return; } tlv_list = storeSwapMetaUnpack(buf, &swap_hdr_sz); if (swap_hdr_sz > len) { /* oops, bad disk file? */ debug(20, 1) ("WARNING: swapfile header too small\n"); storeClientCallback(sc, -1); return; } if (tlv_list == NULL) { debug(20, 1) ("WARNING: failed to unpack meta data\n"); storeClientCallback(sc, -1); return; } /* * Check the meta data and make sure we got the right object. */ for (t = tlv_list; t && swap_object_ok; t = t->next) { switch (t->type) { case STORE_META_KEY: assert(t->length == MD5_DIGEST_CHARS); if (!EBIT_TEST(e->flags, KEY_PRIVATE) && memcmp(t->value, e->hash.key, MD5_DIGEST_CHARS)) { debug(20, 2) ("storeClientReadHeader: swapin MD5 mismatch\n"); debug(20, 2) ("\t%s\n", storeKeyText(t->value)); debug(20, 2) ("\t%s\n", storeKeyText(e->hash.key)); if (isPowTen(++md5_mismatches)) debug(20, 1) ("WARNING: %d swapin MD5 mismatches\n", md5_mismatches); swap_object_ok = 0; } break; case STORE_META_URL: if (NULL == mem->url) (void) 0; /* can't check */ else if (0 == strcasecmp(mem->url, t->value)) (void) 0; /* a match! */ else { debug(20, 1) ("storeClientReadHeader: URL mismatch\n"); debug(20, 1) ("\t{%s} != {%s}\n", t->value, mem->url); swap_object_ok = 0; break; } break; case STORE_META_STD: break; default: debug(20, 1) ("WARNING: got unused STORE_META type %d\n", t->type); break; } } storeSwapTLVFree(tlv_list); if (!swap_object_ok) { storeClientCallback(sc, -1); return; } mem->swap_hdr_sz = swap_hdr_sz; mem->object_sz = e->swap_file_sz - swap_hdr_sz; /* * If our last read got some data the client wants, then give * it to them, otherwise schedule another read. */ body_sz = len - swap_hdr_sz; if (sc->copy_offset < body_sz) { /* * we have (part of) what they want */ copy_sz = XMIN(sc->copy_size, body_sz); debug(20, 3) ("storeClientReadHeader: copying %d bytes of body\n", copy_sz); xmemmove(sc->copy_buf, sc->copy_buf + swap_hdr_sz, copy_sz); if (sc->copy_offset == 0 && len > 0 && mem->reply->sline.status == 0) httpReplyParse(mem->reply, sc->copy_buf, headersEnd(sc->copy_buf, copy_sz)); storeClientCallback(sc, copy_sz); return; } /* * we don't have what the client wants, but at least we now * know the swap header size. */ storeClientFileRead(sc); } int storeClientCopyPending(store_client * sc, StoreEntry * e, void *data) { #if STORE_CLIENT_LIST_DEBUG assert(sc == storeClientListSearch(e->mem_obj, data)); #endif assert(sc->entry == e); if (sc == NULL) return 0; if (sc->callback == NULL) return 0; return 1; } /* * This routine hasn't been optimised to take advantage of the * passed sc. Yet. */ int storeUnregister(store_client * sc, StoreEntry * e, void *data) { MemObject *mem = e->mem_obj; #if STORE_CLIENT_LIST_DEBUG assert(sc == storeClientListSearch(e->mem_obj, data)); #endif if (mem == NULL) return 0; debug(20, 3) ("storeUnregister: called for '%s'\n", storeKeyText(e->hash.key)); if (sc == NULL) return 0; if (mem->clients.head == NULL) return 0; if (sc == mem->clients.head->data) { /* * If we are unregistering the _first_ client for this * entry, then we have to reset the client FD to -1. */ mem->fd = -1; } dlinkDelete(&sc->node, &mem->clients); mem->nclients--; if (e->store_status == STORE_OK && e->swap_status != SWAPOUT_DONE) storeSwapOut(e); if (sc->swapin_sio) { storeClose(sc->swapin_sio); cbdataUnlock(sc->swapin_sio); sc->swapin_sio = NULL; statCounter.swap.ins++; } if (NULL != sc->callback) { /* callback with ssize = -1 to indicate unexpected termination */ debug(20, 3) ("storeUnregister: store_client for %s has a callback\n", mem->url); storeClientCallback(sc, -1); } #if DELAY_POOLS delayUnregisterDelayIdPtr(&sc->delay_id); #endif cbdataUnlock(sc->callback_data); /* we're done with it now */ /*assert(!sc->flags.disk_io_pending); */ cbdataFree(sc); assert(e->lock_count > 0); if (mem->nclients == 0) CheckQuickAbort(e); return 1; } off_t storeLowestMemReaderOffset(const StoreEntry * entry) { const MemObject *mem = entry->mem_obj; off_t lowest = mem->inmem_hi + 1; store_client *sc; dlink_node *nx = NULL; dlink_node *node; for (node = mem->clients.head; node; node = nx) { sc = node->data; nx = node->next; if (sc->callback_data == NULL) /* open slot */ continue; if (sc->type != STORE_MEM_CLIENT) continue; if (sc->type == STORE_DISK_CLIENT) if (NULL != sc->swapin_sio) continue; if (sc->copy_offset < lowest) lowest = sc->copy_offset; } return lowest; } /* Call handlers waiting for data to be appended to E. */ void InvokeHandlers(StoreEntry * e) { int i = 0; MemObject *mem = e->mem_obj; store_client *sc; dlink_node *nx = NULL; dlink_node *node; debug(20, 3) ("InvokeHandlers: %s\n", storeKeyText(e->hash.key)); /* walk the entire list looking for valid callbacks */ for (node = mem->clients.head; node; node = nx) { sc = node->data; nx = node->next; debug(20, 3) ("InvokeHandlers: checking client #%d\n", i++); if (sc->callback_data == NULL) continue; if (sc->callback == NULL) continue; if (sc->flags.disk_io_pending) continue; storeClientCopy2(e, sc); } } int storePendingNClients(const StoreEntry * e) { MemObject *mem = e->mem_obj; int npend = NULL == mem ? 0 : mem->nclients; debug(20, 3) ("storePendingNClients: returning %d\n", npend); return npend; } /* return 1 if the request should be aborted */ static int CheckQuickAbort2(StoreEntry * entry) { int curlen; int minlen; int expectlen; MemObject *mem = entry->mem_obj; assert(mem); debug(20, 3) ("CheckQuickAbort2: entry=%p, mem=%p\n", entry, mem); if (mem->request && !mem->request->flags.cachable) { debug(20, 3) ("CheckQuickAbort2: YES !mem->request->flags.cachable\n"); return 1; } if (EBIT_TEST(entry->flags, KEY_PRIVATE)) { debug(20, 3) ("CheckQuickAbort2: YES KEY_PRIVATE\n"); return 1; } expectlen = mem->reply->content_length + mem->reply->hdr_sz; curlen = (int) mem->inmem_hi; minlen = (int) Config.quickAbort.min << 10; if (minlen < 0) { debug(20, 3) ("CheckQuickAbort2: NO disabled\n"); return 0; } if (curlen > expectlen) { debug(20, 3) ("CheckQuickAbort2: YES bad content length\n"); return 1; } if ((expectlen - curlen) < minlen) { debug(20, 3) ("CheckQuickAbort2: NO only little more left\n"); return 0; } if ((expectlen - curlen) > (Config.quickAbort.max << 10)) { debug(20, 3) ("CheckQuickAbort2: YES too much left to go\n"); return 1; } if (expectlen < 100) { debug(20, 3) ("CheckQuickAbort2: NO avoid FPE\n"); return 0; } if ((curlen / (expectlen / 100)) > Config.quickAbort.pct) { debug(20, 3) ("CheckQuickAbort2: NO past point of no return\n"); return 0; } debug(20, 3) ("CheckQuickAbort2: YES default, returning 1\n"); return 1; } static void CheckQuickAbort(StoreEntry * entry) { if (entry == NULL) return; if (storePendingNClients(entry) > 0) return; if (entry->store_status != STORE_PENDING) return; if (EBIT_TEST(entry->flags, ENTRY_SPECIAL)) return; if (CheckQuickAbort2(entry) == 0) return; statCounter.aborted_requests++; storeAbort(entry); }