* [PATCH v1 0/4] pidfd_open()
@ 2019-03-27 22:19 Christian Brauner
2019-03-27 22:19 ` [PATCH v1 1/4] Make anon_inodes unconditional Christian Brauner
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Christian Brauner @ 2019-03-27 22:19 UTC (permalink / raw)
To: jannh, khlebnikov, luto, dhowells, serge, ebiederm, linux-api,
linux-kernel
Cc: arnd, keescook, adobriyan, tglx, mtk.manpages, bl0pbl33p, ldv,
akpm, oleg, nagarathnam.muthusamy, cyphar, viro, joel, dancol,
Christian Brauner
Hey,
This is v1 of this patchset. No major changes. Just fixing nits that
Jann detected.
After the discussion over the last days, this is a fresh approach to
getting pidfds independent of the translate_pid() patchset.
pidfd_open() allows to retrieve pidfds for processes and removes the
dependency of pidfd on procfs.
These pidfds are allocated using anon_inode_getfd(), are O_CLOEXEC by
default and can be used with the pidfd_send_signal() syscall. They are not
dirfds and as such have the advantage that we can make them pollable or
readable in the future if we see a need to do so. Currently they do not
support any advanced operations. The pidfds are not associated with a
specific pid namespaces but rather only reference struct pid of a given
process in their private_data member.
One of the oustanding issues has been how to get information about a given
process if pidfds are regular file descriptors and do not provide access to
the process /proc/<pid> directory.
Various solutions have been proposed. The one that most people prefer is to
be able to retrieve a file descriptor to /proc/<pid> based on a pidfd (and
the other way around).
IF PROCFD_TO_PIDFD is passed as a flag together with a file descriptor to a
/proc mount in a given pid namespace and a pidfd pidfd_open() will return a
file descriptor to the corresponding /proc/<pid> directory in procfs
mounts' pid namespace. pidfd_open() is very careful to verify that the pid
hasn't been recycled in between.
IF PIDFD_TO_PROCFD is passed as a flag together with a file descriptor
referencing a /proc/<pid> directory a pidfd referencing the struct pid
stashed in /proc/<pid> of the process will be returned.
The pidfd_open() syscalls in that manner resembles openat() as it uses a
flag argument to modify what type of file descriptor will be returned.
The pidfd_open() implementation together with the flags argument strikes me
as an elegant compromise between splitting this into multiple syscalls and
avoiding ioctls().
Note that this patchset also includes Al's and David's commit to make anon
inodes unconditional. The original intention is to make it possible to use
anon inodes in core vfs functions. pidctl() has the same requirement so
David suggested I sent this in alongside this patch. Both are informed of
this.
The syscall comes with appropriate basic testing.
/* Examples */
// Retrieve pidfd
int pidfd = pidfd_open(1234, -1, -1, 0);
// Retrieve /proc/<pid> handle for pidfd
int procfd = open("/proc", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
int procpidfd = pidfd_open(-1, procfd, pidfd, PIDFD_TO_PROCFD);
// Retrieve pidfd for /proc/<pid>
int procpidfd = open("/proc/1234", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
int pidfd = pidfd_open(-1, procpidfd, -1, PROCFD_TO_PIDFD);
Thanks!
Christian
Christian Brauner (3):
pid: add pidfd_open()
signal: support pidfd_open() with pidfd_send_signal()
tests: add pidfd_open() tests
David Howells (1):
Make anon_inodes unconditional
arch/arm/kvm/Kconfig | 1 -
arch/arm64/kvm/Kconfig | 1 -
arch/mips/kvm/Kconfig | 1 -
arch/powerpc/kvm/Kconfig | 1 -
arch/s390/kvm/Kconfig | 1 -
arch/x86/Kconfig | 1 -
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/x86/kvm/Kconfig | 1 -
drivers/base/Kconfig | 1 -
drivers/char/tpm/Kconfig | 1 -
drivers/dma-buf/Kconfig | 1 -
drivers/gpio/Kconfig | 1 -
drivers/iio/Kconfig | 1 -
drivers/infiniband/Kconfig | 1 -
drivers/vfio/Kconfig | 1 -
fs/Makefile | 2 +-
fs/notify/fanotify/Kconfig | 1 -
fs/notify/inotify/Kconfig | 1 -
include/linux/pid.h | 2 +
include/linux/syscalls.h | 2 +
include/uapi/linux/wait.h | 3 +
init/Kconfig | 10 -
kernel/pid.c | 242 ++++++++++++++++++
kernel/signal.c | 14 +-
kernel/sys_ni.c | 3 -
tools/testing/selftests/pidfd/Makefile | 2 +-
.../testing/selftests/pidfd/pidfd_open_test.c | 201 +++++++++++++++
28 files changed, 464 insertions(+), 35 deletions(-)
create mode 100644 tools/testing/selftests/pidfd/pidfd_open_test.c
--
2.21.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v1 1/4] Make anon_inodes unconditional
2019-03-27 22:19 [PATCH v1 0/4] pidfd_open() Christian Brauner
@ 2019-03-27 22:19 ` Christian Brauner
2019-03-27 22:19 ` [PATCH v1 2/4] pid: add pidfd_open() Christian Brauner
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Christian Brauner @ 2019-03-27 22:19 UTC (permalink / raw)
To: jannh, khlebnikov, luto, dhowells, serge, ebiederm, linux-api,
linux-kernel
Cc: arnd, keescook, adobriyan, tglx, mtk.manpages, bl0pbl33p, ldv,
akpm, oleg, nagarathnam.muthusamy, cyphar, viro, joel, dancol,
Christian Brauner
From: David Howells <dhowells@redhat.com>
Make the anon_inodes facility unconditional so that it can be used by core
VFS code and the pidfd_open() syscall.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[christian@brauner.io: adapt commit message to mention pidfd_open()]
Signed-off-by: Christian Brauner <christian@brauner.io>
---
arch/arm/kvm/Kconfig | 1 -
arch/arm64/kvm/Kconfig | 1 -
arch/mips/kvm/Kconfig | 1 -
arch/powerpc/kvm/Kconfig | 1 -
arch/s390/kvm/Kconfig | 1 -
arch/x86/Kconfig | 1 -
arch/x86/kvm/Kconfig | 1 -
drivers/base/Kconfig | 1 -
drivers/char/tpm/Kconfig | 1 -
drivers/dma-buf/Kconfig | 1 -
drivers/gpio/Kconfig | 1 -
drivers/iio/Kconfig | 1 -
drivers/infiniband/Kconfig | 1 -
drivers/vfio/Kconfig | 1 -
fs/Makefile | 2 +-
fs/notify/fanotify/Kconfig | 1 -
fs/notify/inotify/Kconfig | 1 -
init/Kconfig | 10 ----------
18 files changed, 1 insertion(+), 27 deletions(-)
diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index 3f5320f46de2..f591026347a5 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -22,7 +22,6 @@ config KVM
bool "Kernel-based Virtual Machine (KVM) support"
depends on MMU && OF
select PREEMPT_NOTIFIERS
- select ANON_INODES
select ARM_GIC
select ARM_GIC_V3
select ARM_GIC_V3_ITS
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index a3f85624313e..a67121d419a2 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -23,7 +23,6 @@ config KVM
depends on OF
select MMU_NOTIFIER
select PREEMPT_NOTIFIERS
- select ANON_INODES
select HAVE_KVM_CPU_RELAX_INTERCEPT
select HAVE_KVM_ARCH_TLB_FLUSH_ALL
select KVM_MMIO
diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index 4528bc9c3cb1..eac25aef21e0 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -21,7 +21,6 @@ config KVM
depends on MIPS_FP_SUPPORT
select EXPORT_UASM
select PREEMPT_NOTIFIERS
- select ANON_INODES
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select HAVE_KVM_VCPU_ASYNC_IOCTL
select KVM_MMIO
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index bfdde04e4905..f53997a8ca62 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -20,7 +20,6 @@ if VIRTUALIZATION
config KVM
bool
select PREEMPT_NOTIFIERS
- select ANON_INODES
select HAVE_KVM_EVENTFD
select HAVE_KVM_VCPU_ASYNC_IOCTL
select SRCU
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 767453faacfc..1816ee48eadd 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -21,7 +21,6 @@ config KVM
prompt "Kernel-based Virtual Machine (KVM) support"
depends on HAVE_KVM
select PREEMPT_NOTIFIERS
- select ANON_INODES
select HAVE_KVM_CPU_RELAX_INTERCEPT
select HAVE_KVM_VCPU_ASYNC_IOCTL
select HAVE_KVM_EVENTFD
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c1f9b3cf437c..18f2c954464e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -44,7 +44,6 @@ config X86
#
select ACPI_LEGACY_TABLES_LOOKUP if ACPI
select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
- select ANON_INODES
select ARCH_32BIT_OFF_T if X86_32
select ARCH_CLOCKSOURCE_DATA
select ARCH_CLOCKSOURCE_INIT
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 72fa955f4a15..fc042419e670 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -27,7 +27,6 @@ config KVM
depends on X86_LOCAL_APIC
select PREEMPT_NOTIFIERS
select MMU_NOTIFIER
- select ANON_INODES
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQFD
select IRQ_BYPASS_MANAGER
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 059700ea3521..03f067da12ee 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -174,7 +174,6 @@ source "drivers/base/regmap/Kconfig"
config DMA_SHARED_BUFFER
bool
default n
- select ANON_INODES
select IRQ_WORK
help
This option enables the framework for buffer-sharing between
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index 536e55d3919f..f3e4bc490cf0 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -157,7 +157,6 @@ config TCG_CRB
config TCG_VTPM_PROXY
tristate "VTPM Proxy Interface"
depends on TCG_TPM
- select ANON_INODES
---help---
This driver proxies for an emulated TPM (vTPM) running in userspace.
A device /dev/vtpmx is provided that creates a device pair
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index 2e5a0faa2cb1..3fc9c2efc583 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -3,7 +3,6 @@ menu "DMABUF options"
config SYNC_FILE
bool "Explicit Synchronization Framework"
default n
- select ANON_INODES
select DMA_SHARED_BUFFER
---help---
The Sync File Framework adds explicit syncronization via
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 3f50526a771f..0f91600c27ae 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -12,7 +12,6 @@ config ARCH_HAVE_CUSTOM_GPIO_H
menuconfig GPIOLIB
bool "GPIO Support"
- select ANON_INODES
help
This enables GPIO support through the generic GPIO library.
You only need to enable this, if you also want to enable
diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index d08aeb41cd07..1dec0fecb6ef 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -4,7 +4,6 @@
menuconfig IIO
tristate "Industrial I/O support"
- select ANON_INODES
help
The industrial I/O subsystem provides a unified framework for
drivers for many different types of embedded sensors using a
diff --git a/drivers/infiniband/Kconfig b/drivers/infiniband/Kconfig
index a1fb840de45d..d318bab25860 100644
--- a/drivers/infiniband/Kconfig
+++ b/drivers/infiniband/Kconfig
@@ -25,7 +25,6 @@ config INFINIBAND_USER_MAD
config INFINIBAND_USER_ACCESS
tristate "InfiniBand userspace access (verbs and CM)"
- select ANON_INODES
depends on MMU
---help---
Userspace InfiniBand access support. This enables the
diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index 9de5ed38da83..3798d77d131c 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -22,7 +22,6 @@ menuconfig VFIO
tristate "VFIO Non-Privileged userspace driver framework"
depends on IOMMU_API
select VFIO_IOMMU_TYPE1 if (X86 || S390 || ARM || ARM64)
- select ANON_INODES
help
VFIO provides a framework for secure userspace device drivers.
See Documentation/vfio.txt for more details.
diff --git a/fs/Makefile b/fs/Makefile
index 427fec226fae..35945f8139e6 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -25,7 +25,7 @@ obj-$(CONFIG_PROC_FS) += proc_namespace.o
obj-y += notify/
obj-$(CONFIG_EPOLL) += eventpoll.o
-obj-$(CONFIG_ANON_INODES) += anon_inodes.o
+obj-y += anon_inodes.o
obj-$(CONFIG_SIGNALFD) += signalfd.o
obj-$(CONFIG_TIMERFD) += timerfd.o
obj-$(CONFIG_EVENTFD) += eventfd.o
diff --git a/fs/notify/fanotify/Kconfig b/fs/notify/fanotify/Kconfig
index 735bfb2e9190..521dc91d2cb5 100644
--- a/fs/notify/fanotify/Kconfig
+++ b/fs/notify/fanotify/Kconfig
@@ -1,7 +1,6 @@
config FANOTIFY
bool "Filesystem wide access notification"
select FSNOTIFY
- select ANON_INODES
select EXPORTFS
default n
---help---
diff --git a/fs/notify/inotify/Kconfig b/fs/notify/inotify/Kconfig
index b981fc0c8379..0161c74e76e2 100644
--- a/fs/notify/inotify/Kconfig
+++ b/fs/notify/inotify/Kconfig
@@ -1,6 +1,5 @@
config INOTIFY_USER
bool "Inotify support for userspace"
- select ANON_INODES
select FSNOTIFY
default y
---help---
diff --git a/init/Kconfig b/init/Kconfig
index 4592bf7997c0..be8f97e37a76 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1171,9 +1171,6 @@ config LD_DEAD_CODE_DATA_ELIMINATION
config SYSCTL
bool
-config ANON_INODES
- bool
-
config HAVE_UID16
bool
@@ -1378,14 +1375,12 @@ config HAVE_FUTEX_CMPXCHG
config EPOLL
bool "Enable eventpoll support" if EXPERT
default y
- select ANON_INODES
help
Disabling this option will cause the kernel to be built without
support for epoll family of system calls.
config SIGNALFD
bool "Enable signalfd() system call" if EXPERT
- select ANON_INODES
default y
help
Enable the signalfd() system call that allows to receive signals
@@ -1395,7 +1390,6 @@ config SIGNALFD
config TIMERFD
bool "Enable timerfd() system call" if EXPERT
- select ANON_INODES
default y
help
Enable the timerfd() system call that allows to receive timer
@@ -1405,7 +1399,6 @@ config TIMERFD
config EVENTFD
bool "Enable eventfd() system call" if EXPERT
- select ANON_INODES
default y
help
Enable the eventfd() system call that allows to receive both
@@ -1516,7 +1509,6 @@ config KALLSYMS_BASE_RELATIVE
# syscall, maps, verifier
config BPF_SYSCALL
bool "Enable bpf() system call"
- select ANON_INODES
select BPF
select IRQ_WORK
default n
@@ -1533,7 +1525,6 @@ config BPF_JIT_ALWAYS_ON
config USERFAULTFD
bool "Enable userfaultfd() system call"
- select ANON_INODES
depends on MMU
help
Enable the userfaultfd() system call that allows to intercept and
@@ -1600,7 +1591,6 @@ config PERF_EVENTS
bool "Kernel performance events and counters"
default y if PROFILING
depends on HAVE_PERF_EVENTS
- select ANON_INODES
select IRQ_WORK
select SRCU
help
--
2.21.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v1 2/4] pid: add pidfd_open()
2019-03-27 22:19 [PATCH v1 0/4] pidfd_open() Christian Brauner
2019-03-27 22:19 ` [PATCH v1 1/4] Make anon_inodes unconditional Christian Brauner
@ 2019-03-27 22:19 ` Christian Brauner
2019-03-27 22:19 ` [PATCH v1 3/4] signal: support pidfd_open() with pidfd_send_signal() Christian Brauner
2019-03-27 22:19 ` [PATCH v1 4/4] tests: add pidfd_open() tests Christian Brauner
3 siblings, 0 replies; 5+ messages in thread
From: Christian Brauner @ 2019-03-27 22:19 UTC (permalink / raw)
To: jannh, khlebnikov, luto, dhowells, serge, ebiederm, linux-api,
linux-kernel
Cc: arnd, keescook, adobriyan, tglx, mtk.manpages, bl0pbl33p, ldv,
akpm, oleg, nagarathnam.muthusamy, cyphar, viro, joel, dancol,
Christian Brauner
pidfd_open() allows to retrieve pidfds for processes and removes the
dependency of pidfd on procfs. Multiple people have expressed a desire to
do this even when pidfd_send_signal() was merged. It is even recorded in
the commit message for pidfd_send_signal() itself
(cf. commit 3eb39f47934f9d5a3027fe00d906a45fe3a15fad):
Q-06: (Andrew Morton [1])
Is there a cleaner way of obtaining the fd? Another syscall perhaps.
A-06: Userspace can already trivially retrieve file descriptors from procfs
so this is something that we will need to support anyway. Hence,
there's no immediate need to add another syscalls just to make
pidfd_send_signal() not dependent on the presence of procfs. However,
adding a syscalls to get such file descriptors is planned for a
future patchset (cf. [1]).
Alexey made a similar request (cf. [2]). Additionally, Andy made an
argument that we should go forward with non-proc-dirfd file descriptors for
the sake of security and extensibility (cf. [3]).
This will unblock or help move along work on pidfd_wait which is currently
ongoing.
/* pidfds are anon inode file descriptors */
These pidfds are allocated using anon_inode_getfd(), are O_CLOEXEC by
default and can be used with the pidfd_send_signal() syscall. They are not
dirfds and as such have the advantage that we can make them pollable or
readable in the future if we see a need to do so. Currently they do not
support any advanced operations. The pidfds are not associated with a
specific pid namespaces but rather only reference struct pid of a given
process in their private_data member.
/* Process Metadata Access */
One of the oustanding issues has been how to get information about a given
process if pidfds are regular file descriptors and do not provide access to
the process /proc/<pid> directory.
Various solutions have been proposed. The one that most people prefer is to
be able to retrieve a file descriptor to /proc/<pid> based on a pidfd (and
the other way around).
IF PROCFD_TO_PIDFD is passed as a flag together with a file descriptor to a
/proc mount in a given pid namespace and a pidfd pidfd_open() will return a
file descriptor to the corresponding /proc/<pid> directory in procfs
mount's pid namespace. pidfd_open() is very careful to verify that the pid
hasn't been recycled in between.
IF PIDFD_TO_PROCFD is passed as a flag together with a file descriptor
referencing a /proc/<pid> directory a pidfd referencing the struct pid
stashed in /proc/<pid> will be returned.
The pidfd_open() syscall in that manner resembles openat() as it uses a
flag argument to modify what type of file descriptor will be returned.
The pidfd_open() implementation together with the flags argument strikes me
as an elegant compromise between splitting this into multiple syscalls and
avoiding ioctls().
/* Examples */
// Retrieve pidfd
int pidfd = pidfd_open(1234, -1, -1, 0);
// Retrieve /proc/<pid> handle for pidfd
int procfd = open("/proc", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
int procpidfd = pidfd_open(-1, procfd, pidfd, PIDFD_TO_PROCFD);
// Retrieve pidfd for /proc/<pid>
int procpidfd = open("/proc/1234", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
int pidfd = pidfd_open(-1, procpidfd, -1, PROCFD_TO_PIDFD);
/* References */
[1]: https://lore.kernel.org/lkml/20181228233725.722tdfgijxcssg76@brauner.io/
[2]: https://lore.kernel.org/lkml/20190320203910.GA2842@avx2/
[3]: https://lore.kernel.org/lkml/CALCETrXO=V=+qEdLDVPf8eCgLZiB9bOTrUfe0V-U-tUZoeoRDA@mail.gmail.com
Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Jann Horn <jannh@google.com
Cc: David Howells <dhowells@redhat.com>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jonathan Kowalski <bl0pbl33p@gmail.com>
Cc: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
---
/* changelog */
v1:
- Jann Horn <jannh@google.com> in [changelog-1]:
- fix grammar in commit message
- ad O_RDONLY explicitly even if 0
- use fdput() on correct struct fd in pidfd_to_procfd()
- avoid passing O_CLOEXEC explicitly, just remove the flags argument
from pidfd_create_fd()
- Christian Brauner <christian@brauner.io>
- s/pidfd_create_fd()/pidfd_create_cloexec()/
- rename procfd argument to fd
- Yann Droneaud <ydroneaud@opteya.com> [changelog-2]:
- use stricter pid != -1 instead of pid >= 0
[changelog-1]: https://lore.kernel.org/lkml/CAG48ez2QgRQKYeNDpacLGCOuNKVM1g=1PK3KzzO2Uoyn2cKXaQ@mail.gmail.com
[changelog-2]: https://lore.kernel.org/lkml/9254286c02dbe883c14e38ed2af0022d36b17355.camel@opteya.com
---
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
include/linux/pid.h | 2 +
include/linux/syscalls.h | 2 +
include/uapi/linux/wait.h | 3 +
kernel/pid.c | 242 +++++++++++++++++++++++++
6 files changed, 251 insertions(+)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 1f9607ed087c..c8046f261bee 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -433,3 +433,4 @@
425 i386 io_uring_setup sys_io_uring_setup __ia32_sys_io_uring_setup
426 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter
427 i386 io_uring_register sys_io_uring_register __ia32_sys_io_uring_register
+428 i386 pidfd_open sys_pidfd_open __ia32_sys_pidfd_open
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 92ee0b4378d4..f714a3d57b88 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -349,6 +349,7 @@
425 common io_uring_setup __x64_sys_io_uring_setup
426 common io_uring_enter __x64_sys_io_uring_enter
427 common io_uring_register __x64_sys_io_uring_register
+428 common pidfd_open __x64_sys_pidfd_open
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/include/linux/pid.h b/include/linux/pid.h
index b6f4ba16065a..3c8ef5a199ca 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -66,6 +66,8 @@ struct pid
extern struct pid init_struct_pid;
+extern const struct file_operations pidfd_fops;
+
static inline struct pid *get_pid(struct pid *pid)
{
if (pid)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e446806a561f..d8a8ab78f1ff 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -929,6 +929,8 @@ asmlinkage long sys_clock_adjtime32(clockid_t which_clock,
struct old_timex32 __user *tx);
asmlinkage long sys_syncfs(int fd);
asmlinkage long sys_setns(int fd, int nstype);
+asmlinkage long sys_pidfd_open(pid_t pid, int fd, int pidfd,
+ unsigned int flags);
asmlinkage long sys_sendmmsg(int fd, struct mmsghdr __user *msg,
unsigned int vlen, unsigned flags);
asmlinkage long sys_process_vm_readv(pid_t pid,
diff --git a/include/uapi/linux/wait.h b/include/uapi/linux/wait.h
index ac49a220cf2a..8282fc19d8f6 100644
--- a/include/uapi/linux/wait.h
+++ b/include/uapi/linux/wait.h
@@ -18,5 +18,8 @@
#define P_PID 1
#define P_PGID 2
+/* Flags for pidfd_open */
+#define PIDFD_TO_PROCFD 1 /* retrieve file descriptor to /proc/<pid> for pidfd */
+#define PROCFD_TO_PIDFD 2 /* retrieve pidfd for /proc/<pid> */
#endif /* _UAPI_LINUX_WAIT_H */
diff --git a/kernel/pid.c b/kernel/pid.c
index 20881598bdfa..22071c76d2e3 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -26,8 +26,10 @@
*
*/
+#include <linux/anon_inodes.h>
#include <linux/mm.h>
#include <linux/export.h>
+#include <linux/fsnotify.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/rculist.h>
@@ -40,6 +42,7 @@
#include <linux/proc_fs.h>
#include <linux/sched/task.h>
#include <linux/idr.h>
+#include <linux/wait.h>
struct pid init_struct_pid = {
.count = ATOMIC_INIT(1),
@@ -451,6 +454,245 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
return idr_get_next(&ns->idr, &nr);
}
+static int pidfd_release(struct inode *inode, struct file *file)
+{
+ struct pid *pid = file->private_data;
+
+ if (pid) {
+ file->private_data = NULL;
+ put_pid(pid);
+ }
+
+ return 0;
+}
+
+const struct file_operations pidfd_fops = {
+ .release = pidfd_release,
+};
+
+static int pidfd_create_cloexec(struct pid *pid)
+{
+ int fd;
+
+ fd = anon_inode_getfd("pidfd", &pidfd_fops, get_pid(pid),
+ O_RDWR | O_CLOEXEC);
+ if (fd < 0)
+ put_pid(pid);
+
+ return fd;
+}
+
+#ifdef CONFIG_PROC_FS
+static struct pid_namespace *pidfd_get_proc_pid_ns(const struct file *file)
+{
+ struct inode *inode;
+ struct super_block *sb;
+
+ inode = file_inode(file);
+ sb = inode->i_sb;
+ if (sb->s_magic != PROC_SUPER_MAGIC)
+ return ERR_PTR(-EINVAL);
+
+ if (inode->i_ino != PROC_ROOT_INO)
+ return ERR_PTR(-EINVAL);
+
+ return get_pid_ns(inode->i_sb->s_fs_info);
+}
+
+static struct pid *pidfd_get_pid(const struct file *file)
+{
+ if (file->f_op != &pidfd_fops)
+ return ERR_PTR(-EINVAL);
+
+ return get_pid(file->private_data);
+}
+
+static struct file *pidfd_open_proc_pid(const struct file *procf, pid_t pid,
+ const struct pid *pidfd_pid)
+{
+ char name[12]; /* int to strlen + \0 but with */
+ struct file *file;
+ struct pid *proc_pid;
+
+ snprintf(name, sizeof(name), "%d", pid);
+ file = file_open_root(procf->f_path.dentry, procf->f_path.mnt, name,
+ O_DIRECTORY | O_RDONLY | O_NOFOLLOW, 0);
+ if (IS_ERR(file))
+ return file;
+
+ proc_pid = tgid_pidfd_to_pid(file);
+ if (IS_ERR(proc_pid)) {
+ filp_close(file, NULL);
+ return ERR_CAST(proc_pid);
+ }
+
+ if (pidfd_pid != proc_pid) {
+ filp_close(file, NULL);
+ return ERR_PTR(-ESRCH);
+ }
+
+ return file;
+}
+
+static int pidfd_to_procfd(int procfd, int pidfd)
+{
+ long fd;
+ pid_t ns_pid;
+ struct fd fdproc, fdpid;
+ struct file *file = NULL;
+ struct pid *pidfd_pid = NULL;
+ struct pid_namespace *proc_pid_ns = NULL;
+
+ fdproc = fdget(procfd);
+ if (!fdproc.file)
+ return -EBADF;
+
+ fdpid = fdget(pidfd);
+ if (!fdpid.file) {
+ fdput(fdproc);
+ return -EBADF;
+ }
+
+ proc_pid_ns = pidfd_get_proc_pid_ns(fdproc.file);
+ if (IS_ERR(proc_pid_ns)) {
+ fd = PTR_ERR(proc_pid_ns);
+ proc_pid_ns = NULL;
+ goto err;
+ }
+
+ pidfd_pid = pidfd_get_pid(fdpid.file);
+ if (IS_ERR(pidfd_pid)) {
+ fd = PTR_ERR(pidfd_pid);
+ pidfd_pid = NULL;
+ goto err;
+ }
+
+ ns_pid = pid_nr_ns(pidfd_pid, proc_pid_ns);
+ if (!ns_pid) {
+ fd = -ESRCH;
+ goto err;
+ }
+
+ file = pidfd_open_proc_pid(fdproc.file, ns_pid, pidfd_pid);
+ if (IS_ERR(file)) {
+ fd = PTR_ERR(file);
+ file = NULL;
+ goto err;
+ }
+
+ fd = get_unused_fd_flags(O_CLOEXEC);
+ if (fd < 0)
+ goto err;
+
+ fsnotify_open(file);
+ fd_install(fd, file);
+ file = NULL;
+
+err:
+ fdput(fdproc);
+ fdput(fdpid);
+ if (proc_pid_ns)
+ put_pid_ns(proc_pid_ns);
+ put_pid(pidfd_pid);
+ if (file)
+ filp_close(file, NULL);
+
+ return fd;
+}
+
+static int procfd_to_pidfd(int procfd)
+{
+ int fd;
+ struct fd fdproc;
+ struct pid *proc_pid;
+
+ fdproc = fdget(procfd);
+ if (!fdproc.file)
+ return -EBADF;
+
+ proc_pid = tgid_pidfd_to_pid(fdproc.file);
+ if (IS_ERR(proc_pid)) {
+ fdput(fdproc);
+ return PTR_ERR(proc_pid);
+ }
+
+ fd = pidfd_create_cloexec(proc_pid);
+ fdput(fdproc);
+ return fd;
+}
+#else
+static inline int pidfd_to_procfd(int procfd, int pidfd)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int procfd_to_pidfd(int procfd)
+{
+ return -EOPNOTSUPP;
+}
+#endif /* CONFIG_PROC_FS */
+
+/*
+ * pidfd_open - open a pidfd
+ * @pid: pid for which to retrieve a pidfd
+ * @procfd: procfd file descriptor
+ * @pidfd: pidfd file descriptor
+ * @flags: flags to pass
+ *
+ * Creates a new pidfd or translates between pidfds and procfds.
+ * If no flag is passed, pidfd_open() will return a new pidfd for @pid. If
+ * PROCFD_TO_PIDFD is in @flags then a pidfd for struct pid referenced by
+ * @procfd is created. If PIDFD_TO_PROCFD is passed then a file descriptor to
+ * the process /proc/<pid> directory relative to the procfs referenced by
+ * @procfd will be returned.
+ */
+SYSCALL_DEFINE4(pidfd_open, pid_t, pid, int, fd, int, pidfd,
+ unsigned int, flags)
+{
+ long fd = -EINVAL;
+
+ if (flags & ~(PIDFD_TO_PROCFD | PROCFD_TO_PIDFD))
+ return -EINVAL;
+
+ if (!flags) {
+ struct pid *pidfd_pid;
+
+ if (pid <= 0)
+ return -EINVAL;
+
+ if (procfd != -1 || pidfd != -1)
+ return -EINVAL;
+
+ pidfd_pid = find_get_pid(pid);
+ fd = pidfd_create_cloexec(pidfd_pid);
+ put_pid(pidfd_pid);
+ } else if (flags & PIDFD_TO_PROCFD) {
+ if (flags & ~PIDFD_TO_PROCFD)
+ return -EINVAL;
+
+ if (pid != -1)
+ return -EINVAL;
+
+ if (procfd < 0 || pidfd < 0)
+ return -EINVAL;
+
+ fd = pidfd_to_procfd(procfd, pidfd);
+ } else if (flags & PROCFD_TO_PIDFD) {
+ if (flags & ~PROCFD_TO_PIDFD)
+ return -EINVAL;
+
+ if (pid != -1 || pidfd != -1)
+ return -EINVAL;
+
+ if (procfd < 0)
+ return -EINVAL;
+
+ fd = procfd_to_pidfd(procfd);
+ }
+
+ return fd;
+}
+
void __init pid_idr_init(void)
{
/* Verify no one has done anything silly: */
--
2.21.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v1 3/4] signal: support pidfd_open() with pidfd_send_signal()
2019-03-27 22:19 [PATCH v1 0/4] pidfd_open() Christian Brauner
2019-03-27 22:19 ` [PATCH v1 1/4] Make anon_inodes unconditional Christian Brauner
2019-03-27 22:19 ` [PATCH v1 2/4] pid: add pidfd_open() Christian Brauner
@ 2019-03-27 22:19 ` Christian Brauner
2019-03-27 22:19 ` [PATCH v1 4/4] tests: add pidfd_open() tests Christian Brauner
3 siblings, 0 replies; 5+ messages in thread
From: Christian Brauner @ 2019-03-27 22:19 UTC (permalink / raw)
To: jannh, khlebnikov, luto, dhowells, serge, ebiederm, linux-api,
linux-kernel
Cc: arnd, keescook, adobriyan, tglx, mtk.manpages, bl0pbl33p, ldv,
akpm, oleg, nagarathnam.muthusamy, cyphar, viro, joel, dancol,
Christian Brauner
Let pidfd_send_signal() use pidfds retrieved via pidfd_open(). With this
patch pidfd_send_signal() becomes independent of procfs. This fullfils the
request made when we merged the pidfd_send_signal() patchset. The
pidfd_send_signal() syscall is now always available allowing for it to be
used by users without procfs mounted or even users without procfs support
compiled into the kernel.
Signed-off-by: Christian Brauner <christian@brauner.io>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jann Horn <jannh@google.com
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jonathan Kowalski <bl0pbl33p@gmail.com>
Cc: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
---
kernel/signal.c | 14 ++++++++++----
kernel/sys_ni.c | 3 ---
2 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index b7953934aa99..eb97d0cc6ef7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3513,7 +3513,6 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
return kill_something_info(sig, &info, pid);
}
-#ifdef CONFIG_PROC_FS
/*
* Verify that the signaler and signalee either are in the same pid namespace
* or that the signaler's pid namespace is an ancestor of the signalee's pid
@@ -3550,6 +3549,14 @@ static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info)
return copy_siginfo_from_user(kinfo, info);
}
+static struct pid *pidfd_to_pid(const struct file *file)
+{
+ if (file->f_op == &pidfd_fops)
+ return file->private_data;
+
+ return tgid_pidfd_to_pid(file);
+}
+
/**
* sys_pidfd_send_signal - send a signal to a process through a task file
* descriptor
@@ -3581,12 +3588,12 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
if (flags)
return -EINVAL;
- f = fdget_raw(pidfd);
+ f = fdget(pidfd);
if (!f.file)
return -EBADF;
/* Is this a pidfd? */
- pid = tgid_pidfd_to_pid(f.file);
+ pid = pidfd_to_pid(f.file);
if (IS_ERR(pid)) {
ret = PTR_ERR(pid);
goto err;
@@ -3625,7 +3632,6 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
fdput(f);
return ret;
}
-#endif /* CONFIG_PROC_FS */
static int
do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index d21f4befaea4..4d9ae5ea6caf 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -167,9 +167,6 @@ COND_SYSCALL(syslog);
/* kernel/sched/core.c */
-/* kernel/signal.c */
-COND_SYSCALL(pidfd_send_signal);
-
/* kernel/sys.c */
COND_SYSCALL(setregid);
COND_SYSCALL(setgid);
--
2.21.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v1 4/4] tests: add pidfd_open() tests
2019-03-27 22:19 [PATCH v1 0/4] pidfd_open() Christian Brauner
` (2 preceding siblings ...)
2019-03-27 22:19 ` [PATCH v1 3/4] signal: support pidfd_open() with pidfd_send_signal() Christian Brauner
@ 2019-03-27 22:19 ` Christian Brauner
3 siblings, 0 replies; 5+ messages in thread
From: Christian Brauner @ 2019-03-27 22:19 UTC (permalink / raw)
To: jannh, khlebnikov, luto, dhowells, serge, ebiederm, linux-api,
linux-kernel
Cc: arnd, keescook, adobriyan, tglx, mtk.manpages, bl0pbl33p, ldv,
akpm, oleg, nagarathnam.muthusamy, cyphar, viro, joel, dancol,
Christian Brauner
This adds a simple test case for pidfd_open().
Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jann Horn <jannh@google.com
Cc: David Howells <dhowells@redhat.com>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jonathan Kowalski <bl0pbl33p@gmail.com>
Cc: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
---
tools/testing/selftests/pidfd/Makefile | 2 +-
.../testing/selftests/pidfd/pidfd_open_test.c | 201 ++++++++++++++++++
2 files changed, 202 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/pidfd/pidfd_open_test.c
diff --git a/tools/testing/selftests/pidfd/Makefile b/tools/testing/selftests/pidfd/Makefile
index deaf8073bc06..b36c0be70848 100644
--- a/tools/testing/selftests/pidfd/Makefile
+++ b/tools/testing/selftests/pidfd/Makefile
@@ -1,6 +1,6 @@
CFLAGS += -g -I../../../../usr/include/
-TEST_GEN_PROGS := pidfd_test
+TEST_GEN_PROGS := pidfd_test pidfd_open_test
include ../lib.mk
diff --git a/tools/testing/selftests/pidfd/pidfd_open_test.c b/tools/testing/selftests/pidfd/pidfd_open_test.c
new file mode 100644
index 000000000000..07a262a9ef2c
--- /dev/null
+++ b/tools/testing/selftests/pidfd/pidfd_open_test.c
@@ -0,0 +1,201 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <sys/mount.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "../kselftest.h"
+
+static inline int sys_pidfd_open(pid_t pid, int procfd, int pidfd,
+ unsigned int flags)
+{
+ return syscall(__NR_pidfd_open, pid, procfd, pidfd, flags);
+}
+
+static int safe_int(const char *numstr, int *converted)
+{
+ char *err = NULL;
+ signed long int sli;
+
+ errno = 0;
+ sli = strtol(numstr, &err, 0);
+ if (errno == ERANGE && (sli == LONG_MAX || sli == LONG_MIN))
+ return -ERANGE;
+
+ if (errno != 0 && sli == 0)
+ return -EINVAL;
+
+ if (err == numstr || *err != '\0')
+ return -EINVAL;
+
+ if (sli > INT_MAX || sli < INT_MIN)
+ return -ERANGE;
+
+ *converted = (int)sli;
+ return 0;
+}
+
+static int char_left_gc(const char *buffer, size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len; i++) {
+ if (buffer[i] == ' ' ||
+ buffer[i] == '\t')
+ continue;
+
+ return i;
+ }
+
+ return 0;
+}
+
+static int char_right_gc(const char *buffer, size_t len)
+{
+ int i;
+
+ for (i = len - 1; i >= 0; i--) {
+ if (buffer[i] == ' ' ||
+ buffer[i] == '\t' ||
+ buffer[i] == '\n' ||
+ buffer[i] == '\0')
+ continue;
+
+ return i + 1;
+ }
+
+ return 0;
+}
+
+static char *trim_whitespace_in_place(char *buffer)
+{
+ buffer += char_left_gc(buffer, strlen(buffer));
+ buffer[char_right_gc(buffer, strlen(buffer))] = '\0';
+ return buffer;
+}
+
+static pid_t get_pid_from_status_file(int *fd)
+{
+ int ret;
+ FILE *f;
+ size_t n = 0;
+ pid_t result = -1;
+ char *line = NULL;
+
+ /* fd now belongs to FILE and will be closed by fclose() */
+ f = fdopen(*fd, "r");
+ if (!f)
+ return -1;
+
+ while (getline(&line, &n, f) != -1) {
+ char *numstr;
+
+ if (strncmp(line, "Pid:", 4))
+ continue;
+
+ numstr = trim_whitespace_in_place(line + 4);
+ ret = safe_int(numstr, &result);
+ if (ret < 0)
+ goto out;
+
+ break;
+ }
+
+out:
+ free(line);
+ fclose(f);
+ *fd = -1;
+ return result;
+}
+
+int main(int argc, char **argv)
+{
+ int ret = 1;
+ int pidfd = -1, pidfd2 = -1, procfd = -1, procpidfd = -1, statusfd = -1;
+ pid_t pid;
+
+ pidfd = sys_pidfd_open(getpid(), -1, -1, 0);
+ if (pidfd < 0) {
+ ksft_print_msg("%s - failed to open pidfd\n", strerror(errno));
+ goto on_error;
+ }
+
+ procfd = open("/proc", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
+ if (procfd < 0) {
+ ksft_print_msg("%s - failed to open /proc\n", strerror(errno));
+ goto on_error;
+ }
+
+ procpidfd = sys_pidfd_open(-1, procfd, pidfd, PIDFD_TO_PROCFD);
+ if (procpidfd < 0) {
+ ksft_print_msg(
+ "%s - failed to retrieve /proc/<pid> from pidfd\n",
+ strerror(errno));
+ goto on_error;
+ }
+
+ pidfd2 = sys_pidfd_open(-1, procpidfd, -1, PROCFD_TO_PIDFD);
+ if (pidfd2 < 0) {
+ ksft_print_msg(
+ "%s - failed to retrieve pidfd from procpidfd\n",
+ strerror(errno));
+ goto on_error;
+ }
+
+ statusfd = openat(procpidfd, "status", O_CLOEXEC | O_RDONLY);
+ if (statusfd < 0) {
+ ksft_print_msg("%s - failed to open /proc/<pid>/status\n",
+ strerror(errno));
+ goto on_error;
+ }
+
+ pid = get_pid_from_status_file(&statusfd);
+ if (pid < 0) {
+ ksft_print_msg(
+ "%s - failed to retrieve pid from /proc/<pid>/status\n",
+ strerror(errno));
+ goto on_error;
+ }
+
+ if (pid != getpid()) {
+ ksft_print_msg(
+ "%s - actual pid %d does not equal retrieved pid from /proc/<pid>/status\n",
+ strerror(errno), pid, getpid());
+ goto on_error;
+ }
+
+ ret = 0;
+
+on_error:
+ if (pidfd >= 0)
+ close(pidfd);
+
+ if (pidfd2 >= 0)
+ close(pidfd2);
+
+ if (procfd >= 0)
+ close(procfd);
+
+ if (procpidfd >= 0)
+ close(procpidfd);
+
+ if (statusfd >= 0)
+ close(statusfd);
+
+ return !ret ? ksft_exit_pass() : ksft_exit_fail();
+}
--
2.21.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-03-27 22:20 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-03-27 22:19 [PATCH v1 0/4] pidfd_open() Christian Brauner
2019-03-27 22:19 ` [PATCH v1 1/4] Make anon_inodes unconditional Christian Brauner
2019-03-27 22:19 ` [PATCH v1 2/4] pid: add pidfd_open() Christian Brauner
2019-03-27 22:19 ` [PATCH v1 3/4] signal: support pidfd_open() with pidfd_send_signal() Christian Brauner
2019-03-27 22:19 ` [PATCH v1 4/4] tests: add pidfd_open() tests Christian Brauner
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