[RFC][PATCH 4/7] UBC: syscalls (user interface)

[Kirill Korotaev <dev@sw.ru>]

Add the following system calls for UB management:
  1. sys_getluid    - get current UB id
  2. sys_setluid    - changes exec_ and fork_ UBs on current
  3. sys_setublimit - set limits for resources consumtions

Signed-Off-By: Pavel Emelianov <xemul@sw.ru>
Signed-Off-By: Kirill Korotaev <dev@sw.ru>

---
 arch/i386/kernel/syscall_table.S |    3
 arch/ia64/kernel/entry.S         |    3
 arch/sparc/kernel/systbls.S      |    2
 arch/sparc64/kernel/systbls.S    |    2
 include/asm-i386/unistd.h        |    5 +
 include/asm-ia64/unistd.h        |    5 +
 include/asm-powerpc/systbl.h     |    3
 include/asm-powerpc/unistd.h     |    5 +
 include/asm-sparc/unistd.h       |    3
 include/asm-sparc64/unistd.h     |    3
 include/asm-x86_64/unistd.h      |    8 ++
 kernel/ub/Makefile               |    1
 kernel/ub/sys.c                  |  126 +++++++++++++++++++++++++++++++++++++++
 13 files changed, 163 insertions(+), 6 deletions(-)

--- ./arch/i386/kernel/syscall_table.S.ubsys	2006-07-10 12:39:10.000000000 +0400
+++ ./arch/i386/kernel/syscall_table.S	2006-07-31 14:36:59.000000000 +0400
@@ -317,3 +317,6 @@ ENTRY(sys_call_table)
 	.long sys_vmsplice
 	.long sys_move_pages
 	.long sys_getcpu
+	.long sys_getluid
+	.long sys_setluid
+	.long sys_setublimit		/* 320 */
--- ./arch/ia64/kernel/entry.S.ubsys	2006-07-10 12:39:10.000000000 +0400
+++ ./arch/ia64/kernel/entry.S	2006-07-31 15:25:36.000000000 +0400
@@ -1610,5 +1610,8 @@ sys_call_table:
 	data8 sys_sync_file_range		// 1300
 	data8 sys_tee
 	data8 sys_vmsplice
+	daat8 sys_getluid
+	data8 sys_setluid
+	data8 sys_setublimit			// 1305
 
 	.org sys_call_table + 8*NR_syscalls	// guard against failures to increase NR_syscalls
--- ./arch/sparc/kernel/systbls.S.arsys	2006-07-10 12:39:10.000000000 +0400
+++ ./arch/sparc/kernel/systbls.S	2006-08-10 17:07:15.000000000 +0400
@@ -78,7 +78,7 @@ sys_call_table:
 /*285*/	.long sys_mkdirat, sys_mknodat, sys_fchownat, sys_futimesat, sys_fstatat64
 /*290*/	.long sys_unlinkat, sys_renameat, sys_linkat, sys_symlinkat, sys_readlinkat
 /*295*/	.long sys_fchmodat, sys_faccessat, sys_pselect6, sys_ppoll, sys_unshare
-/*300*/	.long sys_set_robust_list, sys_get_robust_list
+/*300*/	.long sys_set_robust_list, sys_get_robust_list, sys_getluid, sys_setluid, sys_setublimit
 
 #ifdef CONFIG_SUNOS_EMUL
 	/* Now the SunOS syscall table. */
--- ./arch/sparc64/kernel/systbls.S.arsys	2006-07-10 12:39:11.000000000 +0400
+++ ./arch/sparc64/kernel/systbls.S	2006-08-10 17:08:52.000000000 +0400
@@ -79,7 +79,7 @@ sys_call_table32:
 	.word sys_mkdirat, sys_mknodat, sys_fchownat, compat_sys_futimesat, compat_sys_fstatat64
 /*290*/	.word sys_unlinkat, sys_renameat, sys_linkat, sys_symlinkat, sys_readlinkat
 	.word sys_fchmodat, sys_faccessat, compat_sys_pselect6, compat_sys_ppoll, sys_unshare
-/*300*/	.word compat_sys_set_robust_list, compat_sys_get_robust_list
+/*300*/	.word compat_sys_set_robust_list, compat_sys_get_robust_list, sys_getluid, sys_setluid, sys_setublimit
 
 #endif /* CONFIG_COMPAT */
 
--- ./include/asm-i386/unistd.h.ubsys	2006-07-10 12:39:19.000000000 +0400
+++ ./include/asm-i386/unistd.h	2006-07-31 15:56:31.000000000 +0400
@@ -323,10 +323,13 @@
 #define __NR_vmsplice		316
 #define __NR_move_pages		317
 #define __NR_getcpu		318
+#define __NR_getluid		319
+#define __NR_setluid		320
+#define __NR_setublimit		321
 
 #ifdef __KERNEL__
 
-#define NR_syscalls 318
+#define NR_syscalls 322
 #include <linux/err.h>
 
 /*
--- ./include/asm-ia64/unistd.h.ubsys	2006-07-10 12:39:19.000000000 +0400
+++ ./include/asm-ia64/unistd.h	2006-07-31 15:57:23.000000000 +0400
@@ -291,11 +291,14 @@
 #define __NR_sync_file_range		1300
 #define __NR_tee			1301
 #define __NR_vmsplice			1302
+#define __NR_getluid			1303
+#define __NR_setluid			1304
+#define __NR_setublimit			1305
 
 #ifdef __KERNEL__
 
 
-#define NR_syscalls			279 /* length of syscall table */
+#define NR_syscalls			282 /* length of syscall table */
 
 #define __ARCH_WANT_SYS_RT_SIGACTION
 
--- ./include/asm-powerpc/systbl.h.arsys	2006-07-10 12:39:19.000000000 +0400
+++ ./include/asm-powerpc/systbl.h	2006-08-10 17:05:53.000000000 +0400
@@ -304,3 +304,6 @@ SYSCALL_SPU(fchmodat)
 SYSCALL_SPU(faccessat)
 COMPAT_SYS_SPU(get_robust_list)
 COMPAT_SYS_SPU(set_robust_list)
+SYSCALL(sys_getluid)
+SYSCALL(sys_setluid)
+SYSCALL(sys_setublimit)
--- ./include/asm-powerpc/unistd.h.arsys	2006-07-10 12:39:19.000000000 +0400
+++ ./include/asm-powerpc/unistd.h	2006-08-10 17:06:28.000000000 +0400
@@ -323,10 +323,13 @@
 #define __NR_faccessat		298
 #define __NR_get_robust_list	299
 #define __NR_set_robust_list	300
+#define __NR_getluid		301
+#define __NR_setluid		302
+#define __NR_setublimit		303
 
 #ifdef __KERNEL__
 
-#define __NR_syscalls		301
+#define __NR_syscalls		304
 
 #define __NR__exit __NR_exit
 #define NR_syscalls	__NR_syscalls
--- ./include/asm-sparc/unistd.h.arsys	2006-07-10 12:39:19.000000000 +0400
+++ ./include/asm-sparc/unistd.h	2006-08-10 17:08:19.000000000 +0400
@@ -318,6 +318,9 @@
 #define __NR_unshare		299
 #define __NR_set_robust_list	300
 #define __NR_get_robust_list	301
+#define __NR_getluid		302
+#define __NR_setluid		303
+#define __NR_setublimit		304
 
 #ifdef __KERNEL__
 /* WARNING: You MAY NOT add syscall numbers larger than 301, since
--- ./include/asm-sparc64/unistd.h.arsys	2006-07-10 12:39:19.000000000 +0400
+++ ./include/asm-sparc64/unistd.h	2006-08-10 17:09:24.000000000 +0400
@@ -320,6 +320,9 @@
 #define __NR_unshare		299
 #define __NR_set_robust_list	300
 #define __NR_get_robust_list	301
+#define __NR_getluid		302
+#define __NR_setluid		303
+#define __NR_setublimit		304
 
 #ifdef __KERNEL__
 /* WARNING: You MAY NOT add syscall numbers larger than 301, since
--- ./include/asm-x86_64/unistd.h.ubsys	2006-07-10 12:39:19.000000000 +0400
+++ ./include/asm-x86_64/unistd.h	2006-07-31 16:00:01.000000000 +0400
@@ -619,10 +619,16 @@ __SYSCALL(__NR_sync_file_range, sys_sync
 __SYSCALL(__NR_vmsplice, sys_vmsplice)
 #define __NR_move_pages		279
 __SYSCALL(__NR_move_pages, sys_move_pages)
+#define __NR_getluid		280
+__SYSCALL(__NR_getluid, sys_getluid)
+#define __NR_setluid		281
+__SYSCALL(__NR_setluid, sys_setluid)
+#define __NR_setublimit		282
+__SYSCALL(__NR_setublimit, sys_setublimit)
 
 #ifdef __KERNEL__
 
-#define __NR_syscall_max __NR_move_pages
+#define __NR_syscall_max __NR_setublimit
 #include <linux/err.h>
 
 #ifndef __NO_STUBS
--- ./kernel/ub/Makefile.ubsys	2006-07-28 14:08:37.000000000 +0400
+++ ./kernel/ub/Makefile	2006-08-01 11:08:39.000000000 +0400
@@ -6,3 +6,4 @@
 
 obj-$(CONFIG_USER_RESOURCE) += beancounter.o
 obj-$(CONFIG_USER_RESOURCE) += misc.o
+obj-y += sys.o
--- ./kernel/ub/sys.c.ubsys	2006-07-28 18:52:18.000000000 +0400
+++ ./kernel/ub/sys.c	2006-08-03 16:14:23.000000000 +0400
@@ -0,0 +1,126 @@
+/*
+ *  kernel/ub/sys.c
+ *
+ *  Copyright (C) 2006 OpenVZ. SWsoft Inc
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <asm/uaccess.h>
+
+#include <ub/beancounter.h>
+#include <ub/task.h>
+
+#ifndef CONFIG_USER_RESOURCE
+asmlinkage long sys_getluid(void)
+{
+	return -ENOSYS;
+}
+
+asmlinkage long sys_setluid(uid_t uid)
+{
+	return -ENOSYS;
+}
+
+asmlinkage long sys_setublimit(uid_t uid, unsigned long resource, 
+		unsigned long *limits)
+{
+	return -ENOSYS;
+}
+#else /* CONFIG_USER_RESOURCE */
+
+/*
+ *	The (rather boring) getluid syscall
+ */
+asmlinkage long sys_getluid(void)
+{
+	struct user_beancounter *ub;
+
+	ub = get_exec_ub();
+	if (ub == NULL)
+		return -EINVAL;
+
+	return ub->ub_uid;
+}
+
+/*
+ *	The setluid syscall
+ */
+asmlinkage long sys_setluid(uid_t uid)
+{
+	int error;
+	struct user_beancounter *ub;
+	struct task_beancounter *task_bc;
+
+	task_bc = &current->task_bc;
+
+	/* You may not disown a setluid */
+	error = -EINVAL;
+	if (uid == (uid_t)-1)
+		goto out;
+
+	/* You may only set an ub as root */
+	error = -EPERM;
+	if (!capable(CAP_SETUID))
+		goto out;
+
+	/* Ok - set up a beancounter entry for this user */
+	error = -ENOBUFS;
+	ub = beancounter_findcreate(uid, NULL, UB_ALLOC);
+	if (ub == NULL)
+		goto out;
+
+	/* install bc */
+	put_beancounter(task_bc->exec_ub);
+	task_bc->exec_ub = ub;
+	put_beancounter(task_bc->fork_sub);
+	task_bc->fork_sub = get_beancounter(ub);
+	error = 0;
+out:
+	return error;
+}
+
+/*
+ *	The setbeanlimit syscall
+ */
+asmlinkage long sys_setublimit(uid_t uid, unsigned long resource,
+		unsigned long *limits)
+{
+	int error;
+	unsigned long flags;
+	struct user_beancounter *ub;
+	unsigned long new_limits[2];
+
+	error = -EPERM;
+	if(!capable(CAP_SYS_RESOURCE))
+		goto out;
+
+	error = -EINVAL;
+	if (resource >= UB_RESOURCES)
+		goto out;
+
+	error = -EFAULT;
+	if (copy_from_user(&new_limits, limits, sizeof(new_limits)))
+		goto out;
+
+	error = -EINVAL;
+	if (new_limits[0] > UB_MAXVALUE || new_limits[1] > UB_MAXVALUE)
+		goto out;
+
+	error = -ENOENT;
+	ub = beancounter_findcreate(uid, NULL, 0);
+	if (ub == NULL)
+		goto out;
+
+	spin_lock_irqsave(&ub->ub_lock, flags);
+	ub->ub_parms[resource].barrier = new_limits[0];
+	ub->ub_parms[resource].limit = new_limits[1];
+	spin_unlock_irqrestore(&ub->ub_lock, flags);
+
+	put_beancounter(ub);
+	error = 0;
+out:
+	return error;
+}
+#endif