Mercurial > hg > nginx
view src/core/ngx_buf.c @ 4576:876e6b0814a5
Fixed signed integer overflows in timer code (ticket #145).
Integer overflow is undefined behaviour in C and this indeed caused
problems on Solaris/SPARC (at least in some cases). Fix is to
subtract unsigned integers instead, and then cast result to a signed
one, which is implementation-defined behaviour and used to work.
Strictly speaking, we should compare (unsigned) result with the maximum
value of the corresponding signed integer type instead, this will be
defined behaviour. This will require much more changes though, and
considered to be overkill for now.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Fri, 06 Apr 2012 23:46:09 +0000 |
parents | d620f497c50f |
children | f9c83484d9ce |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> ngx_buf_t * ngx_create_temp_buf(ngx_pool_t *pool, size_t size) { ngx_buf_t *b; b = ngx_calloc_buf(pool); if (b == NULL) { return NULL; } b->start = ngx_palloc(pool, size); if (b->start == NULL) { return NULL; } /* * set by ngx_calloc_buf(): * * b->file_pos = 0; * b->file_last = 0; * b->file = NULL; * b->shadow = NULL; * b->tag = 0; * and flags */ b->pos = b->start; b->last = b->start; b->end = b->last + size; b->temporary = 1; return b; } ngx_chain_t * ngx_alloc_chain_link(ngx_pool_t *pool) { ngx_chain_t *cl; cl = pool->chain; if (cl) { pool->chain = cl->next; return cl; } cl = ngx_palloc(pool, sizeof(ngx_chain_t)); if (cl == NULL) { return NULL; } return cl; } ngx_chain_t * ngx_create_chain_of_bufs(ngx_pool_t *pool, ngx_bufs_t *bufs) { u_char *p; ngx_int_t i; ngx_buf_t *b; ngx_chain_t *chain, *cl, **ll; p = ngx_palloc(pool, bufs->num * bufs->size); if (p == NULL) { return NULL; } ll = &chain; for (i = 0; i < bufs->num; i++) { b = ngx_calloc_buf(pool); if (b == NULL) { return NULL; } /* * set by ngx_calloc_buf(): * * b->file_pos = 0; * b->file_last = 0; * b->file = NULL; * b->shadow = NULL; * b->tag = 0; * and flags * */ b->pos = p; b->last = p; b->temporary = 1; b->start = p; p += bufs->size; b->end = p; cl = ngx_alloc_chain_link(pool); if (cl == NULL) { return NULL; } cl->buf = b; *ll = cl; ll = &cl->next; } *ll = NULL; return chain; } ngx_int_t ngx_chain_add_copy(ngx_pool_t *pool, ngx_chain_t **chain, ngx_chain_t *in) { ngx_chain_t *cl, **ll; ll = chain; for (cl = *chain; cl; cl = cl->next) { ll = &cl->next; } while (in) { cl = ngx_alloc_chain_link(pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = in->buf; *ll = cl; ll = &cl->next; in = in->next; } *ll = NULL; return NGX_OK; } ngx_chain_t * ngx_chain_get_free_buf(ngx_pool_t *p, ngx_chain_t **free) { ngx_chain_t *cl; if (*free) { cl = *free; *free = cl->next; cl->next = NULL; return cl; } cl = ngx_alloc_chain_link(p); if (cl == NULL) { return NULL; } cl->buf = ngx_calloc_buf(p); if (cl->buf == NULL) { return NULL; } cl->next = NULL; return cl; } void ngx_chain_update_chains(ngx_pool_t *p, ngx_chain_t **free, ngx_chain_t **busy, ngx_chain_t **out, ngx_buf_tag_t tag) { ngx_chain_t *cl; if (*busy == NULL) { *busy = *out; } else { for (cl = *busy; cl->next; cl = cl->next) { /* void */ } cl->next = *out; } *out = NULL; while (*busy) { cl = *busy; if (ngx_buf_size(cl->buf) != 0) { break; } if (cl->buf->tag != tag) { *busy = cl->next; ngx_free_chain(p, cl); continue; } cl->buf->pos = cl->buf->start; cl->buf->last = cl->buf->start; *busy = cl->next; cl->next = *free; *free = cl; } }