1 /* ulimit.c - Modify resource limits
2 *
3 * Copyright 2015 Rob Landley <[email protected]>
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 USE_ULIMIT(OLDTOY(prlimit, ulimit, TOYFLAG_USR|TOYFLAG_BIN))
21
22 config ULIMIT
23 bool "ulimit"
24 default y
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 -P PID to affect (default $PPID) -a Show all limits
33 -S Set/show soft limit -H Set/show hard (maximum) limit
34
35 -c Core file size (blocks) -d Process data segment (KiB)
36 -e Max scheduling priority -f File size (KiB)
37 -i Pending signal count -l Locked memory (KiB)
38 -m Resident Set Size (KiB) -n Number of open files
39 -p Pipe buffer (512 bytes) -q POSIX message queues
40 -r Max realtime priority -R Realtime latency (us)
41 -s Stack size (KiB) -t Total CPU time (s)
42 -u Maximum processes (this UID) -v Virtual memory size (KiB)
43 */
44
45 #define FOR_ulimit
46 #include "toys.h"
47
48 GLOBALS(
49 long P;
50 )
51
52 // This is a linux kernel syscall added in 2.6.36 (git c022a0acad53) which
53 // glibc only exports a wrapper prototype for if you #define _FSF_HURD_RULZE.
54 int prlimit(pid_t pid, int resource, const struct rlimit *new_limit,
55 struct rlimit *old_limit);
56
57 // I'd like to sort the RLIMIT values 0-15, but mips, alpha and sparc
58 // override the asm-generic values for 5-9, and alphabetical order is nice for
59 // humans anyway.
ulimit_main(void)60 void ulimit_main(void)
61 {
62 struct rlimit rr;
63 int i;
64 // map and desc are in the same order as flags.
65 // The Linux kernel implementation of RLIMIT_LOCKS (-x) was removed in 2003.
66 char *flags="cdefilmnpqRrstuv";
67 char map[] = {RLIMIT_CORE, RLIMIT_DATA, RLIMIT_NICE,
68 RLIMIT_FSIZE, RLIMIT_SIGPENDING, RLIMIT_MEMLOCK,
69 RLIMIT_RSS, RLIMIT_NOFILE, 0, RLIMIT_MSGQUEUE,
70 RLIMIT_RTTIME, RLIMIT_RTPRIO, RLIMIT_STACK, RLIMIT_CPU, RLIMIT_NPROC,
71 RLIMIT_AS};
72 char *desc[]={"core dump size (blocks)", "data size (KiB)", "max nice",
73 "file size (blocks)", "pending signals", "locked memory (KiB)",
74 "RSS (KiB)", "open files", "pipe size (512 bytes)", "message queues",
75 "RT time (us)", "RT priority", "stack (KiB)", "cpu time (s)", "processes",
76 "address space (KiB)"};
77
78 if (!(toys.optflags&(FLAG_H-1))) toys.optflags |= FLAG_f;
79 if ((FLAG(a)||FLAG(p)) && toys.optc) error_exit("can't set -ap");
80
81 // Fetch data
82 if (!FLAG(P)) TT.P = getppid();
83
84 for (i=0; i<sizeof(map); i++) {
85 int get = toys.optflags&(FLAG_a|(1<<i));
86
87 if (get && prlimit(TT.P, map[i], 0, &rr)) perror_exit("-%c", flags[i]);
88 if (!toys.optc) {
89 if (FLAG(a)) printf("-%c: %-25s ", flags[i], desc[i]);
90 if (get) {
91 if ((1<<i)&FLAG_p) {
92 if (FLAG(H))
93 xreadfile("/proc/sys/fs/pipe-max-size", toybuf, sizeof(toybuf));
94 else {
95 int pp[2];
96
97 xpipe(pp);
98 sprintf(toybuf, "%d\n", fcntl(*pp, F_GETPIPE_SZ));
99 }
100 printf("%s", toybuf);
101 } else {
102 rlim_t rl = FLAG(H) ? rr.rlim_max : rr.rlim_cur;
103
104 if (rl == RLIM_INFINITY) printf("unlimited\n");
105 else printf("%ld\n", (long)rl);
106 }
107 }
108 }
109 if (toys.optflags&(1<<i)) break;
110 }
111
112 if (FLAG(a)||FLAG(p)) return;
113
114 if (toys.optc) {
115 rlim_t val;
116
117 if (tolower(**toys.optargs) == 'u') val = RLIM_INFINITY;
118 else val = atolx_range(*toys.optargs, 0, LONG_MAX);
119
120 if (FLAG(H)) rr.rlim_max = val;
121 else rr.rlim_cur = val;
122 if (prlimit(TT.P, map[i], &rr, 0)) perror_exit(0);
123 }
124 }
125