Mercurial > hg > nginx-quic
view src/core/ngx_slab.c @ 6874:7cc2d3a96ea3
Fixed trailer construction with limit on FreeBSD and macOS.
The ngx_chain_coalesce_file() function may produce more bytes to send then
requested in the limit passed, as it aligns the last file position
to send to memory page boundary. As a result, (limit - send) may become
negative. This resulted in big positive number when converted to size_t
while calling ngx_output_chain_to_iovec().
Another part of the problem is in ngx_chain_coalesce_file(): it changes cl
to the next chain link even if the current buffer is only partially sent
due to limit.
Therefore, if a file buffer was not expected to be fully sent due to limit,
and was followed by a memory buffer, nginx called sendfile() with a part
of the file buffer, and the memory buffer in trailer. If there were enough
room in the socket buffer, this resulted in a part of the file buffer being
skipped, and corresponding part of the memory buffer sent instead.
The bug was introduced in 8e903522c17a (1.7.8). Configurations affected
are ones using limits, that is, limit_rate and/or sendfile_max_chunk, and
memory buffers after file ones (may happen when using subrequests or
with proxying with disk buffering).
Fix is to explicitly check if (send < limit) before constructing trailer
with ngx_output_chain_to_iovec(). Additionally, ngx_chain_coalesce_file()
was modified to preserve unfinished file buffers in cl.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Fri, 20 Jan 2017 21:12:48 +0300 |
parents | e4590dfd97ff |
children | 94f30939545a |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #define NGX_SLAB_PAGE_MASK 3 #define NGX_SLAB_PAGE 0 #define NGX_SLAB_BIG 1 #define NGX_SLAB_EXACT 2 #define NGX_SLAB_SMALL 3 #if (NGX_PTR_SIZE == 4) #define NGX_SLAB_PAGE_FREE 0 #define NGX_SLAB_PAGE_BUSY 0xffffffff #define NGX_SLAB_PAGE_START 0x80000000 #define NGX_SLAB_SHIFT_MASK 0x0000000f #define NGX_SLAB_MAP_MASK 0xffff0000 #define NGX_SLAB_MAP_SHIFT 16 #define NGX_SLAB_BUSY 0xffffffff #else /* (NGX_PTR_SIZE == 8) */ #define NGX_SLAB_PAGE_FREE 0 #define NGX_SLAB_PAGE_BUSY 0xffffffffffffffff #define NGX_SLAB_PAGE_START 0x8000000000000000 #define NGX_SLAB_SHIFT_MASK 0x000000000000000f #define NGX_SLAB_MAP_MASK 0xffffffff00000000 #define NGX_SLAB_MAP_SHIFT 32 #define NGX_SLAB_BUSY 0xffffffffffffffff #endif #define ngx_slab_slots(pool) \ (ngx_slab_page_t *) ((u_char *) (pool) + sizeof(ngx_slab_pool_t)) #define ngx_slab_page_type(page) ((page)->prev & NGX_SLAB_PAGE_MASK) #define ngx_slab_page_prev(page) \ (ngx_slab_page_t *) ((page)->prev & ~NGX_SLAB_PAGE_MASK) #define ngx_slab_page_addr(pool, page) \ ((((page) - (pool)->pages) << ngx_pagesize_shift) \ + (uintptr_t) (pool)->start) #if (NGX_DEBUG_MALLOC) #define ngx_slab_junk(p, size) ngx_memset(p, 0xA5, size) #elif (NGX_HAVE_DEBUG_MALLOC) #define ngx_slab_junk(p, size) \ if (ngx_debug_malloc) ngx_memset(p, 0xA5, size) #else #define ngx_slab_junk(p, size) #endif static ngx_slab_page_t *ngx_slab_alloc_pages(ngx_slab_pool_t *pool, ngx_uint_t pages); static void ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page, ngx_uint_t pages); static void ngx_slab_error(ngx_slab_pool_t *pool, ngx_uint_t level, char *text); static ngx_uint_t ngx_slab_max_size; static ngx_uint_t ngx_slab_exact_size; static ngx_uint_t ngx_slab_exact_shift; void ngx_slab_init(ngx_slab_pool_t *pool) { u_char *p; size_t size; ngx_int_t m; ngx_uint_t i, n, pages; ngx_slab_page_t *slots, *page; /* STUB */ if (ngx_slab_max_size == 0) { ngx_slab_max_size = ngx_pagesize / 2; ngx_slab_exact_size = ngx_pagesize / (8 * sizeof(uintptr_t)); for (n = ngx_slab_exact_size; n >>= 1; ngx_slab_exact_shift++) { /* void */ } } /**/ pool->min_size = (size_t) 1 << pool->min_shift; slots = ngx_slab_slots(pool); p = (u_char *) slots; size = pool->end - p; ngx_slab_junk(p, size); n = ngx_pagesize_shift - pool->min_shift; for (i = 0; i < n; i++) { /* only "next" is used in list head */ slots[i].slab = 0; slots[i].next = &slots[i]; slots[i].prev = 0; } p += n * sizeof(ngx_slab_page_t); pool->stats = (ngx_slab_stat_t *) p; ngx_memzero(pool->stats, n * sizeof(ngx_slab_stat_t)); p += n * sizeof(ngx_slab_stat_t); size -= n * (sizeof(ngx_slab_page_t) + sizeof(ngx_slab_stat_t)); pages = (ngx_uint_t) (size / (ngx_pagesize + sizeof(ngx_slab_page_t))); pool->pages = (ngx_slab_page_t *) p; ngx_memzero(pool->pages, pages * sizeof(ngx_slab_page_t)); page = pool->pages; /* only "next" is used in list head */ pool->free.slab = 0; pool->free.next = page; pool->free.prev = 0; page->slab = pages; page->next = &pool->free; page->prev = (uintptr_t) &pool->free; pool->start = ngx_align_ptr(p + pages * sizeof(ngx_slab_page_t), ngx_pagesize); m = pages - (pool->end - pool->start) / ngx_pagesize; if (m > 0) { pages -= m; page->slab = pages; } pool->last = pool->pages + pages; pool->pfree = pages; pool->log_nomem = 1; pool->log_ctx = &pool->zero; pool->zero = '\0'; } void * ngx_slab_alloc(ngx_slab_pool_t *pool, size_t size) { void *p; ngx_shmtx_lock(&pool->mutex); p = ngx_slab_alloc_locked(pool, size); ngx_shmtx_unlock(&pool->mutex); return p; } void * ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size) { size_t s; uintptr_t p, n, m, mask, *bitmap; ngx_uint_t i, slot, shift, map; ngx_slab_page_t *page, *prev, *slots; if (size > ngx_slab_max_size) { ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %uz", size); page = ngx_slab_alloc_pages(pool, (size >> ngx_pagesize_shift) + ((size % ngx_pagesize) ? 1 : 0)); if (page) { p = ngx_slab_page_addr(pool, page); } else { p = 0; } goto done; } if (size > pool->min_size) { shift = 1; for (s = size - 1; s >>= 1; shift++) { /* void */ } slot = shift - pool->min_shift; } else { shift = pool->min_shift; slot = 0; } pool->stats[slot].reqs++; ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %uz slot: %ui", size, slot); slots = ngx_slab_slots(pool); page = slots[slot].next; if (page->next != page) { if (shift < ngx_slab_exact_shift) { bitmap = (uintptr_t *) ngx_slab_page_addr(pool, page); map = (ngx_pagesize >> shift) / (sizeof(uintptr_t) * 8); for (n = 0; n < map; n++) { if (bitmap[n] != NGX_SLAB_BUSY) { for (m = 1, i = 0; m; m <<= 1, i++) { if (bitmap[n] & m) { continue; } bitmap[n] |= m; i = (n * sizeof(uintptr_t) * 8 + i) << shift; p = (uintptr_t) bitmap + i; pool->stats[slot].used++; if (bitmap[n] == NGX_SLAB_BUSY) { for (n = n + 1; n < map; n++) { if (bitmap[n] != NGX_SLAB_BUSY) { goto done; } } prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_SMALL; } goto done; } } } } else if (shift == ngx_slab_exact_shift) { for (m = 1, i = 0; m; m <<= 1, i++) { if (page->slab & m) { continue; } page->slab |= m; if (page->slab == NGX_SLAB_BUSY) { prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_EXACT; } p = ngx_slab_page_addr(pool, page) + (i << shift); pool->stats[slot].used++; goto done; } } else { /* shift > ngx_slab_exact_shift */ mask = ((uintptr_t) 1 << (ngx_pagesize >> shift)) - 1; mask <<= NGX_SLAB_MAP_SHIFT; for (m = (uintptr_t) 1 << NGX_SLAB_MAP_SHIFT, i = 0; m & mask; m <<= 1, i++) { if (page->slab & m) { continue; } page->slab |= m; if ((page->slab & NGX_SLAB_MAP_MASK) == mask) { prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; page->next = NULL; page->prev = NGX_SLAB_BIG; } p = ngx_slab_page_addr(pool, page) + (i << shift); pool->stats[slot].used++; goto done; } } ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_alloc(): page is busy"); ngx_debug_point(); } page = ngx_slab_alloc_pages(pool, 1); if (page) { if (shift < ngx_slab_exact_shift) { bitmap = (uintptr_t *) ngx_slab_page_addr(pool, page); n = (ngx_pagesize >> shift) / ((1 << shift) * 8); if (n == 0) { n = 1; } /* "n" elements for bitmap, plus one requested */ bitmap[0] = ((uintptr_t) 2 << n) - 1; map = (ngx_pagesize >> shift) / (sizeof(uintptr_t) * 8); for (i = 1; i < map; i++) { bitmap[i] = 0; } page->slab = shift; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL; slots[slot].next = page; pool->stats[slot].total += (ngx_pagesize >> shift) - n; p = ngx_slab_page_addr(pool, page) + (n << shift); pool->stats[slot].used++; goto done; } else if (shift == ngx_slab_exact_shift) { page->slab = 1; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT; slots[slot].next = page; pool->stats[slot].total += sizeof(uintptr_t) * 8; p = ngx_slab_page_addr(pool, page); pool->stats[slot].used++; goto done; } else { /* shift > ngx_slab_exact_shift */ page->slab = ((uintptr_t) 1 << NGX_SLAB_MAP_SHIFT) | shift; page->next = &slots[slot]; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG; slots[slot].next = page; pool->stats[slot].total += ngx_pagesize >> shift; p = ngx_slab_page_addr(pool, page); pool->stats[slot].used++; goto done; } } p = 0; pool->stats[slot].fails++; done: ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab alloc: %p", (void *) p); return (void *) p; } void * ngx_slab_calloc(ngx_slab_pool_t *pool, size_t size) { void *p; ngx_shmtx_lock(&pool->mutex); p = ngx_slab_calloc_locked(pool, size); ngx_shmtx_unlock(&pool->mutex); return p; } void * ngx_slab_calloc_locked(ngx_slab_pool_t *pool, size_t size) { void *p; p = ngx_slab_alloc_locked(pool, size); if (p) { ngx_memzero(p, size); } return p; } void ngx_slab_free(ngx_slab_pool_t *pool, void *p) { ngx_shmtx_lock(&pool->mutex); ngx_slab_free_locked(pool, p); ngx_shmtx_unlock(&pool->mutex); } void ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p) { size_t size; uintptr_t slab, m, *bitmap; ngx_uint_t i, n, type, slot, shift, map; ngx_slab_page_t *slots, *page; ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, ngx_cycle->log, 0, "slab free: %p", p); if ((u_char *) p < pool->start || (u_char *) p > pool->end) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): outside of pool"); goto fail; } n = ((u_char *) p - pool->start) >> ngx_pagesize_shift; page = &pool->pages[n]; slab = page->slab; type = ngx_slab_page_type(page); switch (type) { case NGX_SLAB_SMALL: shift = slab & NGX_SLAB_SHIFT_MASK; size = (size_t) 1 << shift; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } n = ((uintptr_t) p & (ngx_pagesize - 1)) >> shift; m = (uintptr_t) 1 << (n % (sizeof(uintptr_t) * 8)); n /= sizeof(uintptr_t) * 8; bitmap = (uintptr_t *) ((uintptr_t) p & ~((uintptr_t) ngx_pagesize - 1)); if (bitmap[n] & m) { slot = shift - pool->min_shift; if (page->next == NULL) { slots = ngx_slab_slots(pool); page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_SMALL; page->next->prev = (uintptr_t) page | NGX_SLAB_SMALL; } bitmap[n] &= ~m; n = (ngx_pagesize >> shift) / ((1 << shift) * 8); if (n == 0) { n = 1; } if (bitmap[0] & ~(((uintptr_t) 1 << n) - 1)) { goto done; } map = (ngx_pagesize >> shift) / (sizeof(uintptr_t) * 8); for (i = 1; i < map; i++) { if (bitmap[i]) { goto done; } } ngx_slab_free_pages(pool, page, 1); pool->stats[slot].total -= (ngx_pagesize >> shift) - n; goto done; } goto chunk_already_free; case NGX_SLAB_EXACT: m = (uintptr_t) 1 << (((uintptr_t) p & (ngx_pagesize - 1)) >> ngx_slab_exact_shift); size = ngx_slab_exact_size; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } if (slab & m) { slot = ngx_slab_exact_shift - pool->min_shift; if (slab == NGX_SLAB_BUSY) { slots = ngx_slab_slots(pool); page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_EXACT; page->next->prev = (uintptr_t) page | NGX_SLAB_EXACT; } page->slab &= ~m; if (page->slab) { goto done; } ngx_slab_free_pages(pool, page, 1); pool->stats[slot].total -= sizeof(uintptr_t) * 8; goto done; } goto chunk_already_free; case NGX_SLAB_BIG: shift = slab & NGX_SLAB_SHIFT_MASK; size = (size_t) 1 << shift; if ((uintptr_t) p & (size - 1)) { goto wrong_chunk; } m = (uintptr_t) 1 << ((((uintptr_t) p & (ngx_pagesize - 1)) >> shift) + NGX_SLAB_MAP_SHIFT); if (slab & m) { slot = shift - pool->min_shift; if (page->next == NULL) { slots = ngx_slab_slots(pool); page->next = slots[slot].next; slots[slot].next = page; page->prev = (uintptr_t) &slots[slot] | NGX_SLAB_BIG; page->next->prev = (uintptr_t) page | NGX_SLAB_BIG; } page->slab &= ~m; if (page->slab & NGX_SLAB_MAP_MASK) { goto done; } ngx_slab_free_pages(pool, page, 1); pool->stats[slot].total -= ngx_pagesize >> shift; goto done; } goto chunk_already_free; case NGX_SLAB_PAGE: if ((uintptr_t) p & (ngx_pagesize - 1)) { goto wrong_chunk; } if (!(slab & NGX_SLAB_PAGE_START)) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): page is already free"); goto fail; } if (slab == NGX_SLAB_PAGE_BUSY) { ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): pointer to wrong page"); goto fail; } n = ((u_char *) p - pool->start) >> ngx_pagesize_shift; size = slab & ~NGX_SLAB_PAGE_START; ngx_slab_free_pages(pool, &pool->pages[n], size); ngx_slab_junk(p, size << ngx_pagesize_shift); return; } /* not reached */ return; done: pool->stats[slot].used--; ngx_slab_junk(p, size); return; wrong_chunk: ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): pointer to wrong chunk"); goto fail; chunk_already_free: ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_free(): chunk is already free"); fail: return; } static ngx_slab_page_t * ngx_slab_alloc_pages(ngx_slab_pool_t *pool, ngx_uint_t pages) { ngx_slab_page_t *page, *p; for (page = pool->free.next; page != &pool->free; page = page->next) { if (page->slab >= pages) { if (page->slab > pages) { page[page->slab - 1].prev = (uintptr_t) &page[pages]; page[pages].slab = page->slab - pages; page[pages].next = page->next; page[pages].prev = page->prev; p = (ngx_slab_page_t *) page->prev; p->next = &page[pages]; page->next->prev = (uintptr_t) &page[pages]; } else { p = (ngx_slab_page_t *) page->prev; p->next = page->next; page->next->prev = page->prev; } page->slab = pages | NGX_SLAB_PAGE_START; page->next = NULL; page->prev = NGX_SLAB_PAGE; pool->pfree -= pages; if (--pages == 0) { return page; } for (p = page + 1; pages; pages--) { p->slab = NGX_SLAB_PAGE_BUSY; p->next = NULL; p->prev = NGX_SLAB_PAGE; p++; } return page; } } if (pool->log_nomem) { ngx_slab_error(pool, NGX_LOG_CRIT, "ngx_slab_alloc() failed: no memory"); } return NULL; } static void ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page, ngx_uint_t pages) { ngx_slab_page_t *prev, *join; pool->pfree += pages; page->slab = pages--; if (pages) { ngx_memzero(&page[1], pages * sizeof(ngx_slab_page_t)); } if (page->next) { prev = ngx_slab_page_prev(page); prev->next = page->next; page->next->prev = page->prev; } join = page + page->slab; if (join < pool->last) { if (ngx_slab_page_type(join) == NGX_SLAB_PAGE) { if (join->next != NULL) { pages += join->slab; page->slab += join->slab; prev = ngx_slab_page_prev(join); prev->next = join->next; join->next->prev = join->prev; join->slab = NGX_SLAB_PAGE_FREE; join->next = NULL; join->prev = NGX_SLAB_PAGE; } } } if (page > pool->pages) { join = page - 1; if (ngx_slab_page_type(join) == NGX_SLAB_PAGE) { if (join->slab == NGX_SLAB_PAGE_FREE) { join = ngx_slab_page_prev(join); } if (join->next != NULL) { pages += join->slab; join->slab += page->slab; prev = ngx_slab_page_prev(join); prev->next = join->next; join->next->prev = join->prev; page->slab = NGX_SLAB_PAGE_FREE; page->next = NULL; page->prev = NGX_SLAB_PAGE; page = join; } } } if (pages) { page[pages].prev = (uintptr_t) page; } page->prev = (uintptr_t) &pool->free; page->next = pool->free.next; page->next->prev = (uintptr_t) page; pool->free.next = page; } static void ngx_slab_error(ngx_slab_pool_t *pool, ngx_uint_t level, char *text) { ngx_log_error(level, ngx_cycle->log, 0, "%s%s", text, pool->log_ctx); }