xref: /aosp_15_r20/external/toybox/toys/posix/nice.c (revision cf5a6c84e2b8763fc1a7db14496fd4742913b199)
1*cf5a6c84SAndroid Build Coastguard Worker /* nice.c - Run a program at a different niceness level.
2*cf5a6c84SAndroid Build Coastguard Worker  *
3*cf5a6c84SAndroid Build Coastguard Worker  * Copyright 2010 Rob Landley <[email protected]>
4*cf5a6c84SAndroid Build Coastguard Worker  *
5*cf5a6c84SAndroid Build Coastguard Worker  * See http://opengroup.org/onlinepubs/9699919799/utilities/nice.html
6*cf5a6c84SAndroid Build Coastguard Worker 
7*cf5a6c84SAndroid Build Coastguard Worker USE_NICE(NEWTOY(nice, "^<1n#", TOYFLAG_BIN))
8*cf5a6c84SAndroid Build Coastguard Worker 
9*cf5a6c84SAndroid Build Coastguard Worker config NICE
10*cf5a6c84SAndroid Build Coastguard Worker   bool "nice"
11*cf5a6c84SAndroid Build Coastguard Worker   default y
12*cf5a6c84SAndroid Build Coastguard Worker   help
13*cf5a6c84SAndroid Build Coastguard Worker     usage: nice [-n PRIORITY] COMMAND...
14*cf5a6c84SAndroid Build Coastguard Worker 
15*cf5a6c84SAndroid Build Coastguard Worker     Run a command line at an increased or decreased scheduling priority.
16*cf5a6c84SAndroid Build Coastguard Worker 
17*cf5a6c84SAndroid Build Coastguard Worker     Higher numbers make a program yield more CPU time, from -20 (highest
18*cf5a6c84SAndroid Build Coastguard Worker     priority) to 19 (lowest).  By default processes inherit their parent's
19*cf5a6c84SAndroid Build Coastguard Worker     niceness (usually 0).  By default this command adds 10 to the parent's
20*cf5a6c84SAndroid Build Coastguard Worker     priority.  Only root can set a negative niceness level.
21*cf5a6c84SAndroid Build Coastguard Worker 
22*cf5a6c84SAndroid Build Coastguard Worker     -n	Add given adjustment to priority (default 10)
23*cf5a6c84SAndroid Build Coastguard Worker */
24*cf5a6c84SAndroid Build Coastguard Worker 
25*cf5a6c84SAndroid Build Coastguard Worker #define FOR_nice
26*cf5a6c84SAndroid Build Coastguard Worker #include "toys.h"
27*cf5a6c84SAndroid Build Coastguard Worker 
GLOBALS(long n;)28*cf5a6c84SAndroid Build Coastguard Worker GLOBALS(
29*cf5a6c84SAndroid Build Coastguard Worker   long n;
30*cf5a6c84SAndroid Build Coastguard Worker )
31*cf5a6c84SAndroid Build Coastguard Worker 
32*cf5a6c84SAndroid Build Coastguard Worker void nice_main(void)
33*cf5a6c84SAndroid Build Coastguard Worker {
34*cf5a6c84SAndroid Build Coastguard Worker   if (!toys.optflags) TT.n = 10;
35*cf5a6c84SAndroid Build Coastguard Worker 
36*cf5a6c84SAndroid Build Coastguard Worker   errno = 0;
37*cf5a6c84SAndroid Build Coastguard Worker   if (nice(TT.n)==-1 && errno) {
38*cf5a6c84SAndroid Build Coastguard Worker     toys.exitval = 125;
39*cf5a6c84SAndroid Build Coastguard Worker     perror_exit("Can't set priority");
40*cf5a6c84SAndroid Build Coastguard Worker   }
41*cf5a6c84SAndroid Build Coastguard Worker   xexec(toys.optargs);
42*cf5a6c84SAndroid Build Coastguard Worker }
43