subject:"\[PATCH\] syscall\: introduce sendfd\(\) syscall \(v.2\)"

Re: [PATCH] syscall: introduce sendfd() syscall (v.2)

2014-12-05 Thread Alex Dubov

On Sat, Dec 6, 2014 at 6:23 AM, Bastien ROUCARIES
 wrote:
>
>
> See senfd recvfd in gnulib. It wirk even under solaris
>

What's so special about a thin wrapper around domain sockets/named
fifos (solaris style)?
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Re: [PATCH] syscall: introduce sendfd() syscall (v.2)

2014-12-05 Thread Alex Dubov

On Sat, Dec 6, 2014 at 6:23 AM, Bastien ROUCARIES
roucaries.bast...@gmail.com wrote:


 See senfd recvfd in gnulib. It wirk even under solaris


What's so special about a thin wrapper around domain sockets/named
fifos (solaris style)?
--
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the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH] syscall: introduce sendfd() syscall (v.2)

2014-12-03 Thread Alex Dubov

Present patch introduces exceptionally easy to use, low latency and low
overhead mechanism for transferring file descriptors between cooperating
processes:

int sendfd(pid_t pid, int sig, int fd)

Given a target process pid, the sendfd() will queue a real-time signal for
delivery to task referenced by pid. If signal can be delivered to destination
tasks and it chooses to collect the associated signal info, a new file
descriptor will be created on its behalf, pointing to file originally referred
by fd (the value of newly created file descriptor will be communicated as
integer payload within the siginfo data).

Signed-off-by: Alex Dubov 
---
 arch/x86/syscalls/syscall_32.tbl   |  2 +
 arch/x86/syscalls/syscall_64.tbl   |  1 +
 include/asm-generic/siginfo.h  |  1 +
 include/linux/syscalls.h   |  1 +
 include/uapi/asm-generic/siginfo.h |  1 +
 init/Kconfig   | 11 +
 kernel/signal.c| 89 ++
 kernel/sys_ni.c|  3 ++
 8 files changed, 109 insertions(+)

diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl
index 9fe1b5d..e2782bd 100644
--- a/arch/x86/syscalls/syscall_32.tbl
+++ b/arch/x86/syscalls/syscall_32.tbl
@@ -364,3 +364,5 @@
 355i386getrandom   sys_getrandom
 356i386memfd_createsys_memfd_create
 357i386bpf sys_bpf
+358i386sendfd  sys_sendfd
+
diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
index 281150b..4d6b55d 100644
--- a/arch/x86/syscalls/syscall_64.tbl
+++ b/arch/x86/syscalls/syscall_64.tbl
@@ -328,6 +328,7 @@
 319common  memfd_createsys_memfd_create
 320common  kexec_file_load sys_kexec_file_load
 321common  bpf sys_bpf
+322common  sendfd  sys_sendfd
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/include/asm-generic/siginfo.h b/include/asm-generic/siginfo.h
index 3d1a3af..c8af06f 100644
--- a/include/asm-generic/siginfo.h
+++ b/include/asm-generic/siginfo.h
@@ -12,6 +12,7 @@
 #define __SI_RT(5 << 16)
 #define __SI_MESGQ (6 << 16)
 #define __SI_SYS   (7 << 16)
+#define __SI_FILEP (8 << 16)
 #define __SI_CODE(T,N) ((T) | ((N) & 0x))
 
 struct siginfo;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index bda9b81..1871b72f 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -877,4 +877,5 @@ asmlinkage long sys_seccomp(unsigned int op, unsigned int 
flags,
 asmlinkage long sys_getrandom(char __user *buf, size_t count,
  unsigned int flags);
 asmlinkage long sys_bpf(int cmd, union bpf_attr *attr, unsigned int size);
+asmlinkage long sys_sendfd(pid_t pid, int sig, int fd);
 #endif
diff --git a/include/uapi/asm-generic/siginfo.h 
b/include/uapi/asm-generic/siginfo.h
index ba5be7f..a92e38e 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -148,6 +148,7 @@ typedef struct siginfo {
 #define __SI_RT0
 #define __SI_MESGQ 0
 #define __SI_SYS   0
+#define __SI_FILEP 0
 #define __SI_CODE(T,N) (N)
 #endif
 
diff --git a/init/Kconfig b/init/Kconfig
index 2081a4d..6a62a44 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1505,6 +1505,17 @@ config SIGNALFD
 
  If unsure, say Y.
 
+config SENDFD
+   bool "Enable sendfd() system call" if EXPERT
+   default y
+   help
+ Enable the sendfd() system call that allows rapid duplication
+ of file descriptor across process boundaries. The target process
+ will receive a duplicate file descriptor delivered with one of
+ Posix.1b real-time signals.
+
+ If unsure, say Y.
+
 config TIMERFD
bool "Enable timerfd() system call" if EXPERT
select ANON_INODES
diff --git a/kernel/signal.c b/kernel/signal.c
index 8f0876f..299ee9c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -35,6 +35,11 @@
 #include 
 #include 
 
+#ifdef CONFIG_SENDFD
+#include 
+#include 
+#endif
+
 #define CREATE_TRACE_POINTS
 #include 
 
@@ -394,8 +399,15 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t 
flags, int override_rlimi
 
 static void __sigqueue_free(struct sigqueue *q)
 {
+   if (q->info.si_code == __SI_FILEP) {
+   fput((struct file *)q->info.si_ptr);
+   q->info.si_code = 0;
+   q->info.si_ptr = NULL;
+   }
+
if (q->flags & SIGQUEUE_PREALLOC)
return;
+
atomic_dec(>user->sigpending);
free_uid(q->user);
kmem_cache_free(sigqueue_cachep, q);
@@ -543,6 +555,44 @@ unblock_all_signals(void)
spin_unlock_irqrestore(>sighand->siglock, flags);
 }
 
+#ifdef CONFIG_SENDFD
+
+/*
+ * sendfd_copy_install can only be reached from collect_signal(), that is from
+ * signalfd_read or sigtimedwait.

[PATCH] syscall: introduce sendfd() syscall (v.2)

2014-12-03 Thread Alex Dubov

Present patch introduces exceptionally easy to use, low latency and low
overhead mechanism for transferring file descriptors between cooperating
processes:

int sendfd(pid_t pid, int sig, int fd)

Given a target process pid, the sendfd() will queue a real-time signal for
delivery to task referenced by pid. If signal can be delivered to destination
tasks and it chooses to collect the associated signal info, a new file
descriptor will be created on its behalf, pointing to file originally referred
by fd (the value of newly created file descriptor will be communicated as
integer payload within the siginfo data).

Signed-off-by: Alex Dubov oa...@yahoo.com
---
 arch/x86/syscalls/syscall_32.tbl   |  2 +
 arch/x86/syscalls/syscall_64.tbl   |  1 +
 include/asm-generic/siginfo.h  |  1 +
 include/linux/syscalls.h   |  1 +
 include/uapi/asm-generic/siginfo.h |  1 +
 init/Kconfig   | 11 +
 kernel/signal.c| 89 ++
 kernel/sys_ni.c|  3 ++
 8 files changed, 109 insertions(+)

diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl
index 9fe1b5d..e2782bd 100644
--- a/arch/x86/syscalls/syscall_32.tbl
+++ b/arch/x86/syscalls/syscall_32.tbl
@@ -364,3 +364,5 @@
 355i386getrandom   sys_getrandom
 356i386memfd_createsys_memfd_create
 357i386bpf sys_bpf
+358i386sendfd  sys_sendfd
+
diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
index 281150b..4d6b55d 100644
--- a/arch/x86/syscalls/syscall_64.tbl
+++ b/arch/x86/syscalls/syscall_64.tbl
@@ -328,6 +328,7 @@
 319common  memfd_createsys_memfd_create
 320common  kexec_file_load sys_kexec_file_load
 321common  bpf sys_bpf
+322common  sendfd  sys_sendfd
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/include/asm-generic/siginfo.h b/include/asm-generic/siginfo.h
index 3d1a3af..c8af06f 100644
--- a/include/asm-generic/siginfo.h
+++ b/include/asm-generic/siginfo.h
@@ -12,6 +12,7 @@
 #define __SI_RT(5  16)
 #define __SI_MESGQ (6  16)
 #define __SI_SYS   (7  16)
+#define __SI_FILEP (8  16)
 #define __SI_CODE(T,N) ((T) | ((N)  0x))
 
 struct siginfo;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index bda9b81..1871b72f 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -877,4 +877,5 @@ asmlinkage long sys_seccomp(unsigned int op, unsigned int 
flags,
 asmlinkage long sys_getrandom(char __user *buf, size_t count,
  unsigned int flags);
 asmlinkage long sys_bpf(int cmd, union bpf_attr *attr, unsigned int size);
+asmlinkage long sys_sendfd(pid_t pid, int sig, int fd);
 #endif
diff --git a/include/uapi/asm-generic/siginfo.h 
b/include/uapi/asm-generic/siginfo.h
index ba5be7f..a92e38e 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -148,6 +148,7 @@ typedef struct siginfo {
 #define __SI_RT0
 #define __SI_MESGQ 0
 #define __SI_SYS   0
+#define __SI_FILEP 0
 #define __SI_CODE(T,N) (N)
 #endif
 
diff --git a/init/Kconfig b/init/Kconfig
index 2081a4d..6a62a44 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1505,6 +1505,17 @@ config SIGNALFD
 
  If unsure, say Y.
 
+config SENDFD
+   bool Enable sendfd() system call if EXPERT
+   default y
+   help
+ Enable the sendfd() system call that allows rapid duplication
+ of file descriptor across process boundaries. The target process
+ will receive a duplicate file descriptor delivered with one of
+ Posix.1b real-time signals.
+
+ If unsure, say Y.
+
 config TIMERFD
bool Enable timerfd() system call if EXPERT
select ANON_INODES
diff --git a/kernel/signal.c b/kernel/signal.c
index 8f0876f..299ee9c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -35,6 +35,11 @@
 #include linux/cn_proc.h
 #include linux/compiler.h
 
+#ifdef CONFIG_SENDFD
+#include linux/file.h
+#include linux/fdtable.h
+#endif
+
 #define CREATE_TRACE_POINTS
 #include trace/events/signal.h
 
@@ -394,8 +399,15 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t 
flags, int override_rlimi
 
 static void __sigqueue_free(struct sigqueue *q)
 {
+   if (q-info.si_code == __SI_FILEP) {
+   fput((struct file *)q-info.si_ptr);
+   q-info.si_code = 0;
+   q-info.si_ptr = NULL;
+   }
+
if (q-flags  SIGQUEUE_PREALLOC)
return;
+
atomic_dec(q-user-sigpending);
free_uid(q-user);
kmem_cache_free(sigqueue_cachep, q);
@@ -543,6 +555,44 @@ unblock_all_signals(void)
spin_unlock_irqrestore(current-sighand-siglock, flags);
 }
 
+#ifdef CONFIG_SENDFD
+
+/*
+ * sendfd_copy_install can only be

Re: [PATCH] syscall: introduce sendfd() syscall (v.2)

Re: [PATCH] syscall: introduce sendfd() syscall (v.2)

[PATCH] syscall: introduce sendfd() syscall (v.2)

[PATCH] syscall: introduce sendfd() syscall (v.2)

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