From fbb4c0944422f860484142010bb9f366f3e87bf8 Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Tue, 31 Jan 2017 20:21:14 -0500 Subject: Read curproc from cpu structure, but be careful because after a schedule event myproc() points to a different thread. myproc(); sched(); myproc(); // this proc maybe different than the one before sched Thus, in a function that operates on one thread better to retrieve the current process once at the start of the function. --- sysfile.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'sysfile.c') diff --git a/sysfile.c b/sysfile.c index fae6960..87e508b 100644 --- a/sysfile.c +++ b/sysfile.c @@ -41,10 +41,11 @@ static int fdalloc(struct file *f) { int fd; + struct proc *curproc = myproc(); for(fd = 0; fd < NOFILE; fd++){ - if(myproc()->ofile[fd] == 0){ - myproc()->ofile[fd] = f; + if(curproc->ofile[fd] == 0){ + curproc->ofile[fd] = f; return fd; } } @@ -373,7 +374,8 @@ sys_chdir(void) { char *path; struct inode *ip; - + struct proc *curproc = myproc(); + begin_op(); if(argstr(0, &path) < 0 || (ip = namei(path)) == 0){ end_op(); @@ -386,9 +388,9 @@ sys_chdir(void) return -1; } iunlock(ip); - iput(myproc()->cwd); + iput(curproc->cwd); end_op(); - myproc()->cwd = ip; + curproc->cwd = ip; return 0; } -- cgit v1.2.3