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
19USE_ULIMIT(NEWTOY(ulimit, ">1P#<1SHavutsrRqpnmlifedc[-SH][!apvutsrRqnmlifedc]", TOYFLAG_USR|TOYFLAG_BIN))
20
21config 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
47GLOBALS(
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.
53int 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.
59void 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