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freebsd-skq/bin/sh/miscbltin.c
kib 734382a525 Add a resource limit for the total number of kqueues available to the 
user.  Kqueue now saves the ucred of the allocating thread, to
correctly decrement the counter on close.

Under some specific and not real-world use scenario for kqueue, it is
possible for the kqueues to consume memory proportional to the square
of the number of the filedescriptors available to the process.  Limit
allows administrator to prevent the abuse.

This is kernel-mode side of the change, with the user-mode enabling
commit following.

Reported and tested by:	pho
Discussed with:	jmg
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2013-10-21 16:46:12 +00:00

522 lines
11 KiB
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/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)miscbltin.c 8.4 (Berkeley) 5/4/95";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Miscellaneous builtins.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include "shell.h"
#include "options.h"
#include "var.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "mystring.h"
#include "syntax.h"
#include "trap.h"
#undef eflag
int readcmd(int, char **);
int umaskcmd(int, char **);
int ulimitcmd(int, char **);
/*
* The read builtin. The -r option causes backslashes to be treated like
* ordinary characters.
*
* This uses unbuffered input, which may be avoidable in some cases.
*
* Note that if IFS=' :' then read x y should work so that:
* 'a b' x='a', y='b'
* ' a b ' x='a', y='b'
* ':b' x='', y='b'
* ':' x='', y=''
* '::' x='', y=''
* ': :' x='', y=''
* ':::' x='', y='::'
* ':b c:' x='', y='b c:'
*/
int
readcmd(int argc __unused, char **argv __unused)
{
char **ap;
int backslash;
char c;
int rflag;
char *prompt;
const char *ifs;
char *p;
int startword;
int status;
int i;
int is_ifs;
int saveall = 0;
struct timeval tv;
char *tvptr;
fd_set ifds;
ssize_t nread;
int sig;
rflag = 0;
prompt = NULL;
tv.tv_sec = -1;
tv.tv_usec = 0;
while ((i = nextopt("erp:t:")) != '\0') {
switch(i) {
case 'p':
prompt = shoptarg;
break;
case 'e':
break;
case 'r':
rflag = 1;
break;
case 't':
tv.tv_sec = strtol(shoptarg, &tvptr, 0);
if (tvptr == shoptarg)
error("timeout value");
switch(*tvptr) {
case 0:
case 's':
break;
case 'h':
tv.tv_sec *= 60;
/* FALLTHROUGH */
case 'm':
tv.tv_sec *= 60;
break;
default:
error("timeout unit");
}
break;
}
}
if (prompt && isatty(0)) {
out2str(prompt);
flushall();
}
if (*(ap = argptr) == NULL)
error("arg count");
if ((ifs = bltinlookup("IFS", 1)) == NULL)
ifs = " \t\n";
if (tv.tv_sec >= 0) {
/*
* Wait for something to become available.
*/
FD_ZERO(&ifds);
FD_SET(0, &ifds);
status = select(1, &ifds, NULL, NULL, &tv);
/*
* If there's nothing ready, return an error.
*/
if (status <= 0) {
sig = pendingsig;
return (128 + (sig != 0 ? sig : SIGALRM));
}
}
status = 0;
startword = 2;
backslash = 0;
STARTSTACKSTR(p);
for (;;) {
nread = read(STDIN_FILENO, &c, 1);
if (nread == -1) {
if (errno == EINTR) {
sig = pendingsig;
if (sig == 0)
continue;
status = 128 + sig;
break;
}
warning("read error: %s", strerror(errno));
status = 2;
break;
} else if (nread != 1) {
status = 1;
break;
}
if (c == '\0')
continue;
CHECKSTRSPACE(1, p);
if (backslash) {
backslash = 0;
startword = 0;
if (c != '\n')
USTPUTC(c, p);
continue;
}
if (!rflag && c == '\\') {
backslash++;
continue;
}
if (c == '\n')
break;
if (strchr(ifs, c))
is_ifs = strchr(" \t\n", c) ? 1 : 2;
else
is_ifs = 0;
if (startword != 0) {
if (is_ifs == 1) {
/* Ignore leading IFS whitespace */
if (saveall)
USTPUTC(c, p);
continue;
}
if (is_ifs == 2 && startword == 1) {
/* Only one non-whitespace IFS per word */
startword = 2;
if (saveall)
USTPUTC(c, p);
continue;
}
}
if (is_ifs == 0) {
/* append this character to the current variable */
startword = 0;
if (saveall)
/* Not just a spare terminator */
saveall++;
USTPUTC(c, p);
continue;
}
/* end of variable... */
startword = is_ifs;
if (ap[1] == NULL) {
/* Last variable needs all IFS chars */
saveall++;
USTPUTC(c, p);
continue;
}
STACKSTRNUL(p);
setvar(*ap, stackblock(), 0);
ap++;
STARTSTACKSTR(p);
}
STACKSTRNUL(p);
/* Remove trailing IFS chars */
for (; stackblock() <= --p; *p = 0) {
if (!strchr(ifs, *p))
break;
if (strchr(" \t\n", *p))
/* Always remove whitespace */
continue;
if (saveall > 1)
/* Don't remove non-whitespace unless it was naked */
break;
}
setvar(*ap, stackblock(), 0);
/* Set any remaining args to "" */
while (*++ap != NULL)
setvar(*ap, nullstr, 0);
return status;
}
int
umaskcmd(int argc __unused, char **argv __unused)
{
char *ap;
int mask;
int i;
int symbolic_mode = 0;
while ((i = nextopt("S")) != '\0') {
symbolic_mode = 1;
}
INTOFF;
mask = umask(0);
umask(mask);
INTON;
if ((ap = *argptr) == NULL) {
if (symbolic_mode) {
char u[4], g[4], o[4];
i = 0;
if ((mask & S_IRUSR) == 0)
u[i++] = 'r';
if ((mask & S_IWUSR) == 0)
u[i++] = 'w';
if ((mask & S_IXUSR) == 0)
u[i++] = 'x';
u[i] = '\0';
i = 0;
if ((mask & S_IRGRP) == 0)
g[i++] = 'r';
if ((mask & S_IWGRP) == 0)
g[i++] = 'w';
if ((mask & S_IXGRP) == 0)
g[i++] = 'x';
g[i] = '\0';
i = 0;
if ((mask & S_IROTH) == 0)
o[i++] = 'r';
if ((mask & S_IWOTH) == 0)
o[i++] = 'w';
if ((mask & S_IXOTH) == 0)
o[i++] = 'x';
o[i] = '\0';
out1fmt("u=%s,g=%s,o=%s\n", u, g, o);
} else {
out1fmt("%.4o\n", mask);
}
} else {
if (is_digit(*ap)) {
mask = 0;
do {
if (*ap >= '8' || *ap < '0')
error("Illegal number: %s", *argptr);
mask = (mask << 3) + (*ap - '0');
} while (*++ap != '\0');
umask(mask);
} else {
void *set;
INTOFF;
if ((set = setmode (ap)) == 0)
error("Illegal number: %s", ap);
mask = getmode (set, ~mask & 0777);
umask(~mask & 0777);
free(set);
INTON;
}
}
return 0;
}
/*
* ulimit builtin
*
* This code, originally by Doug Gwyn, Doug Kingston, Eric Gisin, and
* Michael Rendell was ripped from pdksh 5.0.8 and hacked for use with
* ash by J.T. Conklin.
*
* Public domain.
*/
struct limits {
const char *name;
const char *units;
int cmd;
int factor; /* multiply by to get rlim_{cur,max} values */
char option;
};
static const struct limits limits[] = {
#ifdef RLIMIT_CPU
{ "cpu time", "seconds", RLIMIT_CPU, 1, 't' },
#endif
#ifdef RLIMIT_FSIZE
{ "file size", "512-blocks", RLIMIT_FSIZE, 512, 'f' },
#endif
#ifdef RLIMIT_DATA
{ "data seg size", "kbytes", RLIMIT_DATA, 1024, 'd' },
#endif
#ifdef RLIMIT_STACK
{ "stack size", "kbytes", RLIMIT_STACK, 1024, 's' },
#endif
#ifdef RLIMIT_CORE
{ "core file size", "512-blocks", RLIMIT_CORE, 512, 'c' },
#endif
#ifdef RLIMIT_RSS
{ "max memory size", "kbytes", RLIMIT_RSS, 1024, 'm' },
#endif
#ifdef RLIMIT_MEMLOCK
{ "locked memory", "kbytes", RLIMIT_MEMLOCK, 1024, 'l' },
#endif
#ifdef RLIMIT_NPROC
{ "max user processes", (char *)0, RLIMIT_NPROC, 1, 'u' },
#endif
#ifdef RLIMIT_NOFILE
{ "open files", (char *)0, RLIMIT_NOFILE, 1, 'n' },
#endif
#ifdef RLIMIT_VMEM
{ "virtual mem size", "kbytes", RLIMIT_VMEM, 1024, 'v' },
#endif
#ifdef RLIMIT_SWAP
{ "swap limit", "kbytes", RLIMIT_SWAP, 1024, 'w' },
#endif
#ifdef RLIMIT_SBSIZE
{ "sbsize", "bytes", RLIMIT_SBSIZE, 1, 'b' },
#endif
#ifdef RLIMIT_NPTS
{ "pseudo-terminals", (char *)0, RLIMIT_NPTS, 1, 'p' },
#endif
#ifdef RLIMIT_KQUEUES
{ "kqueues", (char *)0, RLIMIT_KQUEUES, 1, 'k' },
#endif
{ (char *) 0, (char *)0, 0, 0, '\0' }
};
int
ulimitcmd(int argc __unused, char **argv __unused)
{
int c;
rlim_t val = 0;
enum { SOFT = 0x1, HARD = 0x2 }
how = SOFT | HARD;
const struct limits *l;
int set, all = 0;
int optc, what;
struct rlimit limit;
what = 'f';
while ((optc = nextopt("HSatfdsmcnuvlbpwk")) != '\0')
switch (optc) {
case 'H':
how = HARD;
break;
case 'S':
how = SOFT;
break;
case 'a':
all = 1;
break;
default:
what = optc;
}
for (l = limits; l->name && l->option != what; l++)
;
if (!l->name)
error("internal error (%c)", what);
set = *argptr ? 1 : 0;
if (set) {
char *p = *argptr;
if (all || argptr[1])
error("too many arguments");
if (strcmp(p, "unlimited") == 0)
val = RLIM_INFINITY;
else {
val = 0;
while ((c = *p++) >= '0' && c <= '9')
{
val = (val * 10) + (long)(c - '0');
if (val < 0)
break;
}
if (c)
error("bad number");
val *= l->factor;
}
}
if (all) {
for (l = limits; l->name; l++) {
char optbuf[40];
if (getrlimit(l->cmd, &limit) < 0)
error("can't get limit: %s", strerror(errno));
if (how & SOFT)
val = limit.rlim_cur;
else if (how & HARD)
val = limit.rlim_max;
if (l->units)
snprintf(optbuf, sizeof(optbuf),
"(%s, -%c) ", l->units, l->option);
else
snprintf(optbuf, sizeof(optbuf),
"(-%c) ", l->option);
out1fmt("%-18s %18s ", l->name, optbuf);
if (val == RLIM_INFINITY)
out1str("unlimited\n");
else
{
val /= l->factor;
out1fmt("%jd\n", (intmax_t)val);
}
}
return 0;
}
if (getrlimit(l->cmd, &limit) < 0)
error("can't get limit: %s", strerror(errno));
if (set) {
if (how & SOFT)
limit.rlim_cur = val;
if (how & HARD)
limit.rlim_max = val;
if (setrlimit(l->cmd, &limit) < 0)
error("bad limit: %s", strerror(errno));
} else {
if (how & SOFT)
val = limit.rlim_cur;
else if (how & HARD)
val = limit.rlim_max;
if (val == RLIM_INFINITY)
out1str("unlimited\n");
else
{
val /= l->factor;
out1fmt("%jd\n", (intmax_t)val);
}
}
return 0;
}
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