svn commit: r286146 - in head/sys: kern sys
Ed Schouten
ed at FreeBSD.org
Sat Aug 1 07:21:16 UTC 2015
Author: ed
Date: Sat Aug 1 07:21:14 2015
New Revision: 286146
URL: https://svnweb.freebsd.org/changeset/base/286146
Log:
Add kern_shm_open().
This allows you to specify the capabilities that the new file descriptor
should have. This allows us to create shared memory objects that only
have the rights we're interested in.
The idea behind restricting the rights is that it makes it a lot easier
for CloudABI to get consistent behaviour across different operating
systems. We only need to make sure that a shared memory implementation
consistently implements the operations that are whitelisted.
Approved by: kib
Obtained from: https://github.com/NuxiNL/freebsd
Modified:
head/sys/kern/uipc_shm.c
head/sys/sys/syscallsubr.h
Modified: head/sys/kern/uipc_shm.c
==============================================================================
--- head/sys/kern/uipc_shm.c Sat Aug 1 03:37:00 2015 (r286145)
+++ head/sys/kern/uipc_shm.c Sat Aug 1 07:21:14 2015 (r286146)
@@ -68,6 +68,7 @@ __FBSDID("$FreeBSD$");
#include <sys/resourcevar.h>
#include <sys/rwlock.h>
#include <sys/stat.h>
+#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
@@ -683,9 +684,9 @@ shm_remove(char *path, Fnv32_t fnv, stru
return (ENOENT);
}
-/* System calls. */
int
-sys_shm_open(struct thread *td, struct shm_open_args *uap)
+kern_shm_open(struct thread *td, const char *userpath, int flags, mode_t mode,
+ struct filecaps *fcaps)
{
struct filedesc *fdp;
struct shmfd *shmfd;
@@ -699,28 +700,27 @@ sys_shm_open(struct thread *td, struct s
/*
* shm_open(2) is only allowed for anonymous objects.
*/
- if (IN_CAPABILITY_MODE(td) && (uap->path != SHM_ANON))
+ if (IN_CAPABILITY_MODE(td) && (userpath != SHM_ANON))
return (ECAPMODE);
#endif
- if ((uap->flags & O_ACCMODE) != O_RDONLY &&
- (uap->flags & O_ACCMODE) != O_RDWR)
+ if ((flags & O_ACCMODE) != O_RDONLY && (flags & O_ACCMODE) != O_RDWR)
return (EINVAL);
- if ((uap->flags & ~(O_ACCMODE | O_CREAT | O_EXCL | O_TRUNC | O_CLOEXEC)) != 0)
+ if ((flags & ~(O_ACCMODE | O_CREAT | O_EXCL | O_TRUNC | O_CLOEXEC)) != 0)
return (EINVAL);
fdp = td->td_proc->p_fd;
- cmode = (uap->mode & ~fdp->fd_cmask) & ACCESSPERMS;
+ cmode = (mode & ~fdp->fd_cmask) & ACCESSPERMS;
- error = falloc(td, &fp, &fd, O_CLOEXEC);
+ error = falloc_caps(td, &fp, &fd, O_CLOEXEC, fcaps);
if (error)
return (error);
/* A SHM_ANON path pointer creates an anonymous object. */
- if (uap->path == SHM_ANON) {
+ if (userpath == SHM_ANON) {
/* A read-only anonymous object is pointless. */
- if ((uap->flags & O_ACCMODE) == O_RDONLY) {
+ if ((flags & O_ACCMODE) == O_RDONLY) {
fdclose(td, fp, fd);
fdrop(fp, td);
return (EINVAL);
@@ -728,7 +728,7 @@ sys_shm_open(struct thread *td, struct s
shmfd = shm_alloc(td->td_ucred, cmode);
} else {
path = malloc(MAXPATHLEN, M_SHMFD, M_WAITOK);
- error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
+ error = copyinstr(userpath, path, MAXPATHLEN, NULL);
#ifdef KTRACE
if (error == 0 && KTRPOINT(curthread, KTR_NAMEI))
ktrnamei(path);
@@ -748,7 +748,7 @@ sys_shm_open(struct thread *td, struct s
shmfd = shm_lookup(path, fnv);
if (shmfd == NULL) {
/* Object does not yet exist, create it if requested. */
- if (uap->flags & O_CREAT) {
+ if (flags & O_CREAT) {
#ifdef MAC
error = mac_posixshm_check_create(td->td_ucred,
path);
@@ -769,17 +769,16 @@ sys_shm_open(struct thread *td, struct s
* reference if requested and permitted.
*/
free(path, M_SHMFD);
- if ((uap->flags & (O_CREAT | O_EXCL)) ==
- (O_CREAT | O_EXCL))
+ if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
error = EEXIST;
else {
#ifdef MAC
error = mac_posixshm_check_open(td->td_ucred,
- shmfd, FFLAGS(uap->flags & O_ACCMODE));
+ shmfd, FFLAGS(flags & O_ACCMODE));
if (error == 0)
#endif
error = shm_access(shmfd, td->td_ucred,
- FFLAGS(uap->flags & O_ACCMODE));
+ FFLAGS(flags & O_ACCMODE));
}
/*
@@ -788,7 +787,7 @@ sys_shm_open(struct thread *td, struct s
* opened with read/write.
*/
if (error == 0 &&
- (uap->flags & (O_ACCMODE | O_TRUNC)) ==
+ (flags & (O_ACCMODE | O_TRUNC)) ==
(O_RDWR | O_TRUNC)) {
#ifdef MAC
error = mac_posixshm_check_truncate(
@@ -809,7 +808,7 @@ sys_shm_open(struct thread *td, struct s
}
}
- finit(fp, FFLAGS(uap->flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops);
+ finit(fp, FFLAGS(flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops);
td->td_retval[0] = fd;
fdrop(fp, td);
@@ -817,6 +816,14 @@ sys_shm_open(struct thread *td, struct s
return (0);
}
+/* System calls. */
+int
+sys_shm_open(struct thread *td, struct shm_open_args *uap)
+{
+
+ return (kern_shm_open(td, uap->path, uap->flags, uap->mode, NULL));
+}
+
int
sys_shm_unlink(struct thread *td, struct shm_unlink_args *uap)
{
Modified: head/sys/sys/syscallsubr.h
==============================================================================
--- head/sys/sys/syscallsubr.h Sat Aug 1 03:37:00 2015 (r286145)
+++ head/sys/sys/syscallsubr.h Sat Aug 1 07:21:14 2015 (r286146)
@@ -204,6 +204,8 @@ int kern_setsockopt(struct thread *td, i
void *optval, enum uio_seg valseg, socklen_t valsize);
int kern_settimeofday(struct thread *td, struct timeval *tv,
struct timezone *tzp);
+int kern_shm_open(struct thread *td, const char *userpath, int flags,
+ mode_t mode, struct filecaps *fcaps);
int kern_shmat(struct thread *td, int shmid, const void *shmaddr,
int shmflg);
int kern_shmctl(struct thread *td, int shmid, int cmd, void *buf,
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