Mercurial > hg > nginx-quic
view src/core/ngx_cpuinfo.c @ 4964:2464ccebdb52
Upstream: fixed SIGSEGV with the "if" directive.
Configuration like
location / {
set $true 1;
if ($true) {
proxy_pass http://backend;
}
if ($true) {
# nothing
}
}
resulted in segmentation fault due to NULL pointer dereference as the
upstream configuration wasn't initialized in an implicit location created
by the last if(), but the r->content_handler was set due to first if().
Instead of committing a suicide by dereferencing a NULL pointer, return
500 (Internal Server Error) in such cases, i.e. if uscf is NULL. Better
fix would be to avoid such cases by fixing the "if" directive handling,
but it's out of scope of this patch.
Prodded by Piotr Sikora.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 13 Dec 2012 16:05:59 +0000 |
parents | d620f497c50f |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #if (( __i386__ || __amd64__ ) && ( __GNUC__ || __INTEL_COMPILER )) static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf); #if ( __i386__ ) static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf) { /* * we could not use %ebx as output parameter if gcc builds PIC, * and we could not save %ebx on stack, because %esp is used, * when the -fomit-frame-pointer optimization is specified. */ __asm__ ( " mov %%ebx, %%esi; " " cpuid; " " mov %%eax, (%1); " " mov %%ebx, 4(%1); " " mov %%edx, 8(%1); " " mov %%ecx, 12(%1); " " mov %%esi, %%ebx; " : : "a" (i), "D" (buf) : "ecx", "edx", "esi", "memory" ); } #else /* __amd64__ */ static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf) { uint32_t eax, ebx, ecx, edx; __asm__ ( "cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (i) ); buf[0] = eax; buf[1] = ebx; buf[2] = edx; buf[3] = ecx; } #endif /* auto detect the L2 cache line size of modern and widespread CPUs */ void ngx_cpuinfo(void) { u_char *vendor; uint32_t vbuf[5], cpu[4], model; vbuf[0] = 0; vbuf[1] = 0; vbuf[2] = 0; vbuf[3] = 0; vbuf[4] = 0; ngx_cpuid(0, vbuf); vendor = (u_char *) &vbuf[1]; if (vbuf[0] == 0) { return; } ngx_cpuid(1, cpu); if (ngx_strcmp(vendor, "GenuineIntel") == 0) { switch ((cpu[0] & 0xf00) >> 8) { /* Pentium */ case 5: ngx_cacheline_size = 32; break; /* Pentium Pro, II, III */ case 6: ngx_cacheline_size = 32; model = ((cpu[0] & 0xf0000) >> 8) | (cpu[0] & 0xf0); if (model >= 0xd0) { /* Intel Core, Core 2, Atom */ ngx_cacheline_size = 64; } break; /* * Pentium 4, although its cache line size is 64 bytes, * it prefetches up to two cache lines during memory read */ case 15: ngx_cacheline_size = 128; break; } } else if (ngx_strcmp(vendor, "AuthenticAMD") == 0) { ngx_cacheline_size = 64; } } #else void ngx_cpuinfo(void) { } #endif