mirror of https://github.com/golang/go.git
555da73c56
The kernel implementation of the fast system call path, the one invoked by the SYSCALL instruction, is broken for restarting system calls. A C program demonstrating this is below. Change the system calls to use INT $0x80 instead, because that (perhaps slightly slower) system call path actually works. I filed http://www.freebsd.org/cgi/query-pr.cgi?pr=182161. The C program demonstrating that it is FreeBSD's fault is below. It reports the same "Bad address" failures from wait. #include <sys/time.h> #include <sys/signal.h> #include <pthread.h> #include <unistd.h> #include <stdlib.h> #include <stdio.h> #include <string.h> static void handler(int); static void* looper(void*); int main(void) { int i; struct sigaction sa; pthread_cond_t cond; pthread_mutex_t mu; memset(&sa, 0, sizeof sa); sa.sa_handler = handler; sa.sa_flags = SA_RESTART; memset(&sa.sa_mask, 0xff, sizeof sa.sa_mask); sigaction(SIGCHLD, &sa, 0); for(i=0; i<2; i++) pthread_create(0, 0, looper, 0); pthread_mutex_init(&mu, 0); pthread_mutex_lock(&mu); pthread_cond_init(&cond, 0); for(;;) pthread_cond_wait(&cond, &mu); return 0; } static void handler(int sig) { } int mywait4(int pid, int *stat, int options, struct rusage *rusage) { int result; asm("movq %%rcx, %%r10; syscall" : "=a" (result) : "a" (7), "D" (pid), "S" (stat), "d" (options), "c" (rusage)); } static void* looper(void *v) { int pid, stat, out; struct rusage rusage; for(;;) { if((pid = fork()) == 0) _exit(0); out = mywait4(pid, &stat, 0, &rusage); if(out != pid) { printf("wait4 returned %d\n", out); } } } Fixes #6372. R=golang-dev, bradfitz CC=golang-dev https://golang.org/cl/13582047 |
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README
This is the source code repository for the Go programming language.
For documentation about how to install and use Go,
visit http://golang.org/ or load doc/install.html in your web browser.
After installing Go, you can view a nicely formatted
doc/install.html by running godoc --http=:6060
and then visiting http://localhost:6060/doc/install.html.
Unless otherwise noted, the Go source files are distributed
under the BSD-style license found in the LICENSE file.
--
Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set
the environment variable $GOROOT to the full path of the go
directory (the one containing this README). You can omit the
variable if you unpack it into /usr/local/go, or if you rebuild
from sources by running all.bash (see doc/install.html).
You should also add the Go binary directory $GOROOT/bin
to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might
put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See doc/install.html for more details.