1 /* ulimit.c - Modify resource limits
2 *
3 * Copyright 2015 Rob Landley <rob@landley.net>
4 *
5 * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ulimit.html
6 * And man prlimit(2).
7 *
8 * Deviations from posix: The units on -f are supposed to be 512 byte
9 * "blocks" (no other options are specified, and even hard drives don't
10 * do that anymore). Bash uses 1024 byte blocks, so they don't care either.
11 * We consistently use bytes everywhere we can.
12 *
13 * Deviations from bash: Sizes are in bytes (instead of -p 512 and -f 1024).
14 * Bash's -p value has been wrong since 2010 (git 35f3d14dbbc5).
15 * The kernel implementation of RLIMIT_LOCKS (-x) was removed from Linux in
16 * 2003. Bash never implemented -b (it's in the help but unrecognized at
17 * runtime). We support -P to affect processes other than us.
18
19 USE_ULIMIT(NEWTOY(ulimit, ">1P#<1SHavutsrRqpnmlifedc[-SH][!apvutsrRqnmlifedc]", TOYFLAG_USR|TOYFLAG_BIN))
20
21 config ULIMIT
22 bool "ulimit"
23 default y
24 help
25 usage: ulimit [-P PID] [-SHRacdefilmnpqrstuv] [LIMIT]
26
27 Print or set resource limits for process number PID. If no LIMIT specified
28 (or read-only -ap selected) display current value (sizes in bytes).
29 Default is ulimit -P $PPID -Sf" (show soft filesize of your shell).
30
31 -S Set/show soft limit -H Set/show hard (maximum) limit
32 -a Show all limits -c Core file size
33 -d Process data segment -e Max scheduling priority
34 -f Output file size -i Pending signal count
35 -l Locked memory -m Resident Set Size
36 -n Number of open files -p Pipe buffer
37 -q Posix message queue -r Max Real-time priority
38 -R Realtime latency (usec) -s Stack size
39 -t Total CPU time (in seconds) -u Maximum processes (under this UID)
40 -v Virtual memory size -P PID to affect (default $PPID)
41 */
42
43 #define FOR_ulimit
44 #include "toys.h"
45
46 GLOBALS(
47 long pid;
48 )
49
50 // This is a linux kernel syscall added in 2.6.36 (git c022a0acad53) which
51 // glibc only exports a wrapper prototype for if you #define _FSF_HURD_RULZE.
52 int prlimit(pid_t pid, int resource, const struct rlimit *new_limit,
53 struct rlimit *old_limit);
54
55 // I'd like to sort the RLIMIT values 0-15, but mips, alpha and sparc
56 // override the asm-generic values for 5-9. Also, the kernel implementation
57 // of RLIMIT_LOCKS (-x) was removed from Linux in 2003.
ulimit_main(void)58 void ulimit_main(void)
59 {
60 struct rlimit rr;
61 int i;
62 // Order is cdefilmnqRrstuv
63 char map[] = {RLIMIT_CORE, RLIMIT_DATA, RLIMIT_NICE, RLIMIT_FSIZE,
64 RLIMIT_SIGPENDING, RLIMIT_MEMLOCK, RLIMIT_RSS, RLIMIT_NOFILE, 0,
65 RLIMIT_MSGQUEUE, RLIMIT_RTTIME, RLIMIT_RTPRIO, RLIMIT_STACK,
66 RLIMIT_CPU, RLIMIT_NPROC, RLIMIT_AS};
67
68 if (!(toys.optflags&(FLAG_H-1))) toys.optflags |= FLAG_f;
69 if ((toys.optflags&(FLAG_a|FLAG_p)) && toys.optc) error_exit("can't set -ap");
70
71 // Fetch data
72 if (!(toys.optflags&FLAG_P)) TT.pid = getppid();
73
74 for (i=0; i<sizeof(map); i++) {
75 char *flags="cdefilmnpqRrstuv";
76
77 int get = toys.optflags&(FLAG_a|(1<<i));
78
79 if (get && prlimit(TT.pid, map[i], 0, &rr)) perror_exit("-%c", flags[i]);
80 if (!toys.optc) {
81 if (toys.optflags&FLAG_a) printf("-%c: ", flags[i]);
82 if (get) {
83 if ((1<<i)&FLAG_p) {
84 if (toys.optflags&FLAG_H)
85 xreadfile("/proc/sys/fs/pipe-max-size", toybuf, sizeof(toybuf));
86 else {
87 int pp[2];
88
89 xpipe(pp);
90 sprintf(toybuf, "%d\n", fcntl(*pp, F_GETPIPE_SZ));
91 }
92 printf("%s", toybuf);
93 } else {
94 rlim_t rl = (toys.optflags&FLAG_H) ? rr.rlim_max : rr.rlim_cur;
95
96 if (rl == RLIM_INFINITY) printf("unlimited\n");
97 else printf("%ld\n", (long)rl);
98 }
99 }
100 }
101 if (toys.optflags&(1<<i)) break;
102 }
103
104 if (toys.optflags&(FLAG_a|FLAG_p)) return;
105
106 if (toys.optc) {
107 rlim_t val;
108
109 if (tolower(**toys.optargs == 'i')) val = RLIM_INFINITY;
110 else val = atolx_range(*toys.optargs, 0, LONG_MAX);
111
112 if (toys.optflags&FLAG_H) rr.rlim_max = val;
113 else rr.rlim_cur = val;
114 if (prlimit(TT.pid, map[i], &rr, 0)) perror_exit(0);
115 }
116 }
117