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 depends on TOYBOX_PRLIMIT
25 help
26 usage: ulimit [-P PID] [-SHRacdefilmnpqrstuv] [LIMIT]
27
28 Print or set resource limits for process number PID. If no LIMIT specified
29 (or read-only -ap selected) display current value (sizes in bytes).
30 Default is ulimit -P $PPID -Sf" (show soft filesize of your shell).
31
32 -S Set/show soft limit -H Set/show hard (maximum) limit
33 -a Show all limits -c Core file size
34 -d Process data segment -e Max scheduling priority
35 -f Output file size -i Pending signal count
36 -l Locked memory -m Resident Set Size
37 -n Number of open files -p Pipe buffer
38 -q Posix message queue -r Max Real-time priority
39 -R Realtime latency (usec) -s Stack size
40 -t Total CPU time (in seconds) -u Maximum processes (under this UID)
41 -v Virtual memory size -P PID to affect (default $PPID)
42 */
43
44 #define FOR_ulimit
45 #include "toys.h"
46
47 GLOBALS(
48 long pid;
49 )
50
51 // This is a linux kernel syscall added in 2.6.36 (git c022a0acad53) which
52 // glibc only exports a wrapper prototype for if you #define _FSF_HURD_RULZE.
53 int prlimit(pid_t pid, int resource, const struct rlimit *new_limit,
54 struct rlimit *old_limit);
55
56 // I'd like to sort the RLIMIT values 0-15, but mips, alpha and sparc
57 // override the asm-generic values for 5-9. Also, the kernel implementation
58 // of RLIMIT_LOCKS (-x) was removed from Linux in 2003.
ulimit_main(void)59 void ulimit_main(void)
60 {
61 struct rlimit rr;
62 int i;
63 // Order is cdefilmnqRrstuv
64 char map[] = {RLIMIT_CORE, RLIMIT_DATA, RLIMIT_NICE, RLIMIT_FSIZE,
65 RLIMIT_SIGPENDING, RLIMIT_MEMLOCK, RLIMIT_RSS, RLIMIT_NOFILE, 0,
66 RLIMIT_MSGQUEUE, RLIMIT_RTTIME, RLIMIT_RTPRIO, RLIMIT_STACK,
67 RLIMIT_CPU, RLIMIT_NPROC, RLIMIT_AS};
68
69 if (!(toys.optflags&(FLAG_H-1))) toys.optflags |= FLAG_f;
70 if ((toys.optflags&(FLAG_a|FLAG_p)) && toys.optc) error_exit("can't set -ap");
71
72 // Fetch data
73 if (!(toys.optflags&FLAG_P)) TT.pid = getppid();
74
75 for (i=0; i<sizeof(map); i++) {
76 char *flags="cdefilmnpqRrstuv";
77
78 int get = toys.optflags&(FLAG_a|(1<<i));
79
80 if (get && prlimit(TT.pid, map[i], 0, &rr)) perror_exit("-%c", flags[i]);
81 if (!toys.optc) {
82 if (toys.optflags&FLAG_a) printf("-%c: ", flags[i]);
83 if (get) {
84 if ((1<<i)&FLAG_p) {
85 if (toys.optflags&FLAG_H)
86 xreadfile("/proc/sys/fs/pipe-max-size", toybuf, sizeof(toybuf));
87 else {
88 int pp[2];
89
90 xpipe(pp);
91 sprintf(toybuf, "%d\n", fcntl(*pp, F_GETPIPE_SZ));
92 }
93 printf("%s", toybuf);
94 } else {
95 rlim_t rl = (toys.optflags&FLAG_H) ? rr.rlim_max : rr.rlim_cur;
96
97 if (rl == RLIM_INFINITY) printf("unlimited\n");
98 else printf("%ld\n", (long)rl);
99 }
100 }
101 }
102 if (toys.optflags&(1<<i)) break;
103 }
104
105 if (toys.optflags&(FLAG_a|FLAG_p)) return;
106
107 if (toys.optc) {
108 rlim_t val;
109
110 if (tolower(**toys.optargs) == 'u') val = RLIM_INFINITY;
111 else val = atolx_range(*toys.optargs, 0, LONG_MAX);
112
113 if (toys.optflags&FLAG_H) rr.rlim_max = val;
114 else rr.rlim_cur = val;
115 if (prlimit(TT.pid, map[i], &rr, 0)) perror_exit(0);
116 }
117 }
118