From 628ff7c1d8d8466a5ad8078bd0206a130f8b8a51 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Fri, 18 Dec 2009 09:41:24 -0800 Subject: [PATCH] anonfd: Allow making anon files read-only It seems a couple places such as arch/ia64/kernel/perfmon.c and drivers/infiniband/core/uverbs_main.c could use anon_inode_getfile() instead of a private pseudo-fs + alloc_file(), if only there were a way to get a read-only file. So provide this by having anon_inode_getfile() create a read-only file if we pass O_RDONLY in flags. Signed-off-by: Roland Dreier Signed-off-by: Al Viro --- fs/anon_inodes.c | 12 ++++++++++-- fs/eventfd.c | 2 +- fs/eventpoll.c | 2 +- fs/signalfd.c | 2 +- fs/timerfd.c | 2 +- kernel/perf_event.c | 2 +- virt/kvm/kvm_main.c | 4 ++-- 7 files changed, 17 insertions(+), 9 deletions(-) diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index 2c994591f4d..598237e9722 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -89,11 +89,19 @@ struct file *anon_inode_getfile(const char *name, struct qstr this; struct path path; struct file *file; + fmode_t mode; int error; if (IS_ERR(anon_inode_inode)) return ERR_PTR(-ENODEV); + switch (flags & O_ACCMODE) { + case O_RDONLY: mode = FMODE_READ; break; + case O_WRONLY: mode = FMODE_WRITE; break; + case O_RDWR: mode = FMODE_READ | FMODE_WRITE; break; + default: return ERR_PTR(-EINVAL); + } + if (fops->owner && !try_module_get(fops->owner)) return ERR_PTR(-ENOENT); @@ -121,13 +129,13 @@ struct file *anon_inode_getfile(const char *name, d_instantiate(path.dentry, anon_inode_inode); error = -ENFILE; - file = alloc_file(&path, FMODE_READ | FMODE_WRITE, fops); + file = alloc_file(&path, mode, fops); if (!file) goto err_dput; file->f_mapping = anon_inode_inode->i_mapping; file->f_pos = 0; - file->f_flags = O_RDWR | (flags & O_NONBLOCK); + file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); file->f_version = 0; file->private_data = priv; diff --git a/fs/eventfd.c b/fs/eventfd.c index 8b47e4200e6..d26402ff06e 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -339,7 +339,7 @@ struct file *eventfd_file_create(unsigned int count, int flags) ctx->flags = flags; file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx, - flags & EFD_SHARED_FCNTL_FLAGS); + O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS)); if (IS_ERR(file)) eventfd_free_ctx(ctx); diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 366c503f965..bd056a5b4ef 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1206,7 +1206,7 @@ SYSCALL_DEFINE1(epoll_create1, int, flags) * a file structure and a free file descriptor. */ error = anon_inode_getfd("[eventpoll]", &eventpoll_fops, ep, - flags & O_CLOEXEC); + O_RDWR | (flags & O_CLOEXEC)); if (error < 0) ep_free(ep); diff --git a/fs/signalfd.c b/fs/signalfd.c index b07565c9438..1dabe4ee02f 100644 --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -236,7 +236,7 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask, * anon_inode_getfd() will install the fd. */ ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx, - flags & (O_CLOEXEC | O_NONBLOCK)); + O_RDWR | (flags & (O_CLOEXEC | O_NONBLOCK))); if (ufd < 0) kfree(ctx); } else { diff --git a/fs/timerfd.c b/fs/timerfd.c index b042bd7034b..1bfc95ad5f7 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -200,7 +200,7 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS); ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx, - flags & TFD_SHARED_FCNTL_FLAGS); + O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS)); if (ufd < 0) kfree(ctx); diff --git a/kernel/perf_event.c b/kernel/perf_event.c index e0eb4a2fe18..1f38270f08c 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -4724,7 +4724,7 @@ SYSCALL_DEFINE5(perf_event_open, if (IS_ERR(event)) goto err_put_context; - err = anon_inode_getfd("[perf_event]", &perf_fops, event, 0); + err = anon_inode_getfd("[perf_event]", &perf_fops, event, O_RDWR); if (err < 0) goto err_free_put_context; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e1f2bf8d7b1..b5af8816761 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1177,7 +1177,7 @@ static struct file_operations kvm_vcpu_fops = { */ static int create_vcpu_fd(struct kvm_vcpu *vcpu) { - return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, 0); + return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, O_RDWR); } /* @@ -1638,7 +1638,7 @@ static int kvm_dev_ioctl_create_vm(void) kvm = kvm_create_vm(); if (IS_ERR(kvm)) return PTR_ERR(kvm); - fd = anon_inode_getfd("kvm-vm", &kvm_vm_fops, kvm, 0); + fd = anon_inode_getfd("kvm-vm", &kvm_vm_fops, kvm, O_RDWR); if (fd < 0) kvm_put_kvm(kvm);