| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame^] | 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * nice() for uClibc |
| 4 | * |
| 5 | * Copyright (C) 2005 by Manuel Novoa III <mjn3@codepoet.org> |
| 6 | * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org> |
| 7 | * |
| 8 | * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. |
| 9 | */ |
| 10 | |
| 11 | #include <sys/syscall.h> |
| 12 | #include <unistd.h> |
| 13 | #include <sys/resource.h> |
| 14 | |
| 15 | |
| 16 | #ifdef __NR_nice |
| 17 | |
| 18 | # define __NR___syscall_nice __NR_nice |
| 19 | static __inline__ _syscall1(int, __syscall_nice, int, incr) |
| 20 | |
| 21 | #else |
| 22 | |
| 23 | # include <limits.h> |
| 24 | |
| 25 | |
| 26 | static __inline__ int int_add_no_wrap(int a, int b) |
| 27 | { |
| 28 | int s = a + b; |
| 29 | |
| 30 | if (b < 0) { |
| 31 | if (s > a) s = INT_MIN; |
| 32 | } else { |
| 33 | if (s < a) s = INT_MAX; |
| 34 | } |
| 35 | |
| 36 | return s; |
| 37 | } |
| 38 | |
| 39 | static __inline__ int __syscall_nice(int incr) |
| 40 | { |
| 41 | int old_priority; |
| 42 | # if 1 |
| 43 | /* This should never fail. */ |
| 44 | old_priority = getpriority(PRIO_PROCESS, 0); |
| 45 | # else |
| 46 | /* But if you want to be paranoid... */ |
| 47 | int old_errno; |
| 48 | |
| 49 | old_errno = errno; |
| 50 | __set_errno(0); |
| 51 | old_priority = getpriority(PRIO_PROCESS, 0); |
| 52 | if ((old_priority == -1) && errno) { |
| 53 | return -1; |
| 54 | } |
| 55 | __set_errno(old_errno); |
| 56 | # endif |
| 57 | |
| 58 | if (setpriority(PRIO_PROCESS, 0, int_add_no_wrap(old_priority, incr))) { |
| 59 | __set_errno(EPERM); /* SUSv3 mandates EPERM for nice failure. */ |
| 60 | return -1; |
| 61 | } |
| 62 | |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | #endif |
| 67 | |
| 68 | int nice(int incr) |
| 69 | { |
| 70 | if (__syscall_nice(incr)) { |
| 71 | return -1; |
| 72 | } |
| 73 | |
| 74 | return getpriority(PRIO_PROCESS, 0); |
| 75 | } |