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 USE_ULIMIT(OLDTOY(prlimit, ulimit, TOYFLAG_USR|TOYFLAG_BIN))
21
22 config ULIMIT
23 bool "ulimit"
24 default y
25 depends on TOYBOX_PRLIMIT
26 help
27 usage: ulimit [-P PID] [-SHRacdefilmnpqrstuv] [LIMIT]
28
29 Print or set resource limits for process number PID. If no LIMIT specified
30 (or read-only -ap selected) display current value (sizes in bytes).
31 Default is ulimit -P $PPID -Sf" (show soft filesize of your shell).
32
33 -P PID to affect (default $PPID) -a Show all limits
34 -S Set/show soft limit -H Set/show hard (maximum) limit
35
36 -c Core file size (blocks) -d Process data segment (KiB)
37 -e Max scheduling priority -f File size (KiB)
38 -i Pending signal count -l Locked memory (KiB)
39 -m Resident Set Size (KiB) -n Number of open files
40 -p Pipe buffer (512 bytes) -q POSIX message queues
41 -r Max realtime priority -R Realtime latency (us)
42 -s Stack size (KiB) -t Total CPU time (s)
43 -u Maximum processes (this UID) -v Virtual memory size (KiB)
44 */
45
46 #define FOR_ulimit
47 #include "toys.h"
48
49 GLOBALS(
50 long P;
51 )
52
53 // This is a linux kernel syscall added in 2.6.36 (git c022a0acad53) which
54 // glibc only exports a wrapper prototype for if you #define _FSF_HURD_RULZE.
55 int prlimit(pid_t pid, int resource, const struct rlimit *new_limit,
56 struct rlimit *old_limit);
57
58 // I'd like to sort the RLIMIT values 0-15, but mips, alpha and sparc
59 // override the asm-generic values for 5-9, and alphabetical order is nice for
60 // humans anyway.
ulimit_main(void)61 void ulimit_main(void)
62 {
63 struct rlimit rr;
64 int i;
65 // map and desc are in the same order as flags.
66 // The Linux kernel implementation of RLIMIT_LOCKS (-x) was removed in 2003.
67 char *flags="cdefilmnpqRrstuv";
68 char map[] = {RLIMIT_CORE, RLIMIT_DATA, RLIMIT_NICE,
69 RLIMIT_FSIZE, RLIMIT_SIGPENDING, RLIMIT_MEMLOCK,
70 RLIMIT_RSS, RLIMIT_NOFILE, 0, RLIMIT_MSGQUEUE,
71 RLIMIT_RTTIME, RLIMIT_RTPRIO, RLIMIT_STACK, RLIMIT_CPU, RLIMIT_NPROC,
72 RLIMIT_AS};
73 char *desc[]={"core dump size (blocks)", "data size (KiB)", "max nice",
74 "file size (blocks)", "pending signals", "locked memory (KiB)",
75 "RSS (KiB)", "open files", "pipe size (512 bytes)", "message queues",
76 "RT time (us)", "RT priority", "stack (KiB)", "cpu time (s)", "processes",
77 "address space (KiB)"};
78
79 if (!(toys.optflags&(FLAG_H-1))) toys.optflags |= FLAG_f;
80 if ((FLAG(a)||FLAG(p)) && toys.optc) error_exit("can't set -ap");
81
82 // Fetch data
83 if (!FLAG(P)) TT.P = getppid();
84
85 for (i=0; i<sizeof(map); i++) {
86 int get = toys.optflags&(FLAG_a|(1<<i));
87
88 if (get && prlimit(TT.P, map[i], 0, &rr)) perror_exit("-%c", flags[i]);
89 if (!toys.optc) {
90 if (FLAG(a)) printf("-%c: %-25s ", flags[i], desc[i]);
91 if (get) {
92 if ((1<<i)&FLAG_p) {
93 if (FLAG(H))
94 xreadfile("/proc/sys/fs/pipe-max-size", toybuf, sizeof(toybuf));
95 else {
96 int pp[2];
97
98 xpipe(pp);
99 sprintf(toybuf, "%d\n", fcntl(*pp, F_GETPIPE_SZ));
100 }
101 printf("%s", toybuf);
102 } else {
103 rlim_t rl = FLAG(H) ? rr.rlim_max : rr.rlim_cur;
104
105 if (rl == RLIM_INFINITY) printf("unlimited\n");
106 else printf("%ld\n", (long)rl);
107 }
108 }
109 }
110 if (toys.optflags&(1<<i)) break;
111 }
112
113 if (FLAG(a)||FLAG(p)) return;
114
115 if (toys.optc) {
116 rlim_t val;
117
118 if (tolower(**toys.optargs) == 'u') val = RLIM_INFINITY;
119 else val = atolx_range(*toys.optargs, 0, LONG_MAX);
120
121 if (FLAG(H)) rr.rlim_max = val;
122 else rr.rlim_cur = val;
123 if (prlimit(TT.P, map[i], &rr, 0)) perror_exit(0);
124 }
125 }
126