prlimit: new command

This program uses the prlimit() system call to get and/or set resource limits
for a given process.

[kzak@redhat,com: - improve <soft:hard> parsing,
                  - use short cmdline options compatible with ulimits
                  - add --verbose mode
                  - fix gcc warnings]

Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 571 insertions, 0 deletions

diff --git a/sys-utils/prlimit.c b/sys-utils/prlimit.c
new file mode 100644
index 000000000..74c7fc98e
--- /dev/null
+++ b/sys-utils/prlimit.c
@@ -0,0 +1,571 @@
+/*
+ *  prlimit - get/set process resource limits.
+ *
+ *  Copyright (C) 2011 Davidlohr Bueso <dave@gnu.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <errno.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <assert.h>
+#include <unistd.h>
+#include <sys/resource.h>
+
+#include "c.h"
+#include "nls.h"
+#include "tt.h"
+#include "xalloc.h"
+#include "strutils.h"
+
+enum {
+	AS,
+	CORE,
+	CPU,
+	DATA,
+	FSIZE,
+	LOCKS,
+	MEMLOCK,
+	MSGQUEUE,
+	NICE,
+	NOFILE,
+	NPROC,
+	RSS,
+	RTPRIO,
+	RTTIME,
+	SIGPENDING,
+	STACK
+};
+
+struct prlimit_desc {
+	const char *name;
+	const char *help;
+	int resource;
+};
+
+static struct prlimit_desc prlimit_desc[] =
+{
+	[AS]         = { "AS",         N_("address space limit"),                RLIMIT_AS },
+	[CORE]       = { "CORE",       N_("max core file size"),                 RLIMIT_CORE },
+	[CPU]        = { "CPU",        N_("CPU time in secs"),                   RLIMIT_CPU },
+	[DATA]       = { "DATA",       N_("max data size"),                      RLIMIT_DATA },
+	[FSIZE]      = { "FSIZE",      N_("max file size"),                      RLIMIT_FSIZE },
+	[LOCKS]      = { "LOCKS",      N_("max amount of file locks held"),      RLIMIT_LOCKS },
+	[MEMLOCK]    = { "MEMLOCK",    N_("max locked-in-memory address space"), RLIMIT_MEMLOCK },
+	[MSGQUEUE]   = { "MSGQUEUE",   N_("max bytes in POSIX mqueues"),         RLIMIT_MSGQUEUE },
+	[NICE]       = { "NICE",       N_("max nice prio allowed to raise"),     RLIMIT_NICE },
+	[NOFILE]     = { "NOFILE",     N_("max amount of open files"),           RLIMIT_NOFILE },
+	[NPROC]      = { "NPROC",      N_("max number of processes"),            RLIMIT_NPROC },
+	[RSS]        = { "RSS",        N_("max resident set size"),              RLIMIT_RSS },
+	[RTPRIO]     = { "RTPRIO",     N_("max real-time priority"),             RLIMIT_RTPRIO },
+	[RTTIME]     = { "RTTIME",     N_("timeout for real-time tasks"),        RLIMIT_RTTIME },
+	[SIGPENDING] = { "SIGPENDING", N_("max amount of pending signals"),      RLIMIT_SIGPENDING },
+	[STACK]      = { "STACK",      N_("max stack size"),                     RLIMIT_STACK }
+};
+
+struct prlimit {
+	struct rlimit rlim;
+	struct prlimit_desc *desc;
+	int modify;
+};
+
+#define PRLIMIT_EMPTY_LIMIT	{{ 0, 0, }, NULL, 0 }
+
+enum {
+	COL_HELP,
+	COL_RES,
+	COL_SOFT,
+	COL_HARD,
+};
+
+/* column names */
+struct colinfo {
+	const char	*name;	/* header */
+	double		whint;	/* width hint (N < 1 is in percent of termwidth) */
+	int		flags;	/* TT_FL_* */
+	const char      *help;
+};
+
+/* columns descriptions */
+struct colinfo infos[] = {
+	[COL_RES]     = { "RESOURCE",    0.25, TT_FL_TRUNC, N_("resource name") },
+	[COL_HELP]    = { "DESCRIPTION", 0.1,  TT_FL_TRUNC, N_("resource description")},
+	[COL_SOFT]    = { "SOFT",        0.1,  TT_FL_RIGHT, N_("soft limit")},
+	[COL_HARD]    = { "HARD",        1,    TT_FL_RIGHT, N_("hard limit (ceiling)")},
+};
+
+#define NCOLS ARRAY_SIZE(infos)
+#define MAX_RESOURCES ARRAY_SIZE(prlimit_desc)
+
+#define INFINITY_STR	"unlimited"
+#define INFINITY_STRLEN	(sizeof(INFINITY_STR) - 1)
+
+#define PRLIMIT_SOFT	(1 << 1)
+#define PRLIMIT_HARD	(1 << 2)
+
+/* array with IDs of enabled columns */
+static int columns[NCOLS], ncolumns;
+static pid_t pid; /* calling process (default) */
+static int verbose;
+
+static void __attribute__ ((__noreturn__)) usage(FILE * out)
+{
+	size_t i;
+
+	fputs(USAGE_HEADER, out);
+
+	fprintf(out,
+		_(" %s [options]\n"), program_invocation_short_name);
+
+	fputs(_("\nGeneral Options:\n"), out);
+	fputs(_(" -p, --pid <pid>        process id\n"
+		" -o, --output <type>    define which output columns to use\n"
+		"     --verbose          verbose output\n"
+		" -h, --help             display this help and exit\n"
+		" -V, --version          output version information and exit\n"), out);
+
+	fputs(_("\nResources Options:\n"), out);
+	fputs(_(" -c, --core             maximum size of core files created\n"
+		" -d, --data             maximum size of a process's data segment\n"
+		" -e, --nice             maximum nice priority allowed to raise\n"
+		" -f, --fsize            maximum size of files written by the process\n"
+		" -i, --sigpending       maximum amount of pending signals\n"
+		" -l, --memlock          maximum size a process may lock into memory\n"
+		" -m, --rss              maximum resident set size\n"
+		" -n, --nofile           maximum amount of open files\n"
+		" -q, --msgqueue         maximum bytes in POSIX message queues\n"
+		" -r, --rtprio           maximum real-time scheduling priority\n"
+		" -s, --stack            maximum stack size\n"
+		" -t, --cpu              maximum amount of CPU time in seconds\n"
+		" -u, --nproc            maximum number of user processes\n"
+		" -v, --as               size of virtual memory\n"
+		" -x, --locks            maximum number of file locks\n"
+		" -y, --rttime           CPU time in microseconds a process scheduled\n"
+		"                        under real-time scheduling\n"), out);
+
+	fputs(_("\nAvailable columns (for --output):\n"), out);
+
+	for (i = 0; i < NCOLS; i++)
+		fprintf(out, " %11s  %s\n", infos[i].name, _(infos[i].help));
+
+	fprintf(out, USAGE_MAN_TAIL("prlimit(1)"));
+
+	exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+static inline int get_column_id(int num)
+{
+	assert(ARRAY_SIZE(columns) == NCOLS);
+	assert(num < ncolumns);
+	assert(columns[num] < (int) NCOLS);
+
+	return columns[num];
+}
+
+static inline struct colinfo *get_column_info(unsigned num)
+{
+	return &infos[ get_column_id(num) ];
+}
+
+static void add_tt_line(struct tt *tt, struct prlimit *l)
+{
+	int i;
+	struct tt_line *line;
+
+	assert(tt);
+	assert(l);
+
+	line = tt_add_line(tt, NULL);
+	if (!line) {
+		warn(_("failed to add line to output"));
+		return;
+	}
+
+	for (i = 0; i < ncolumns; i++) {
+		char *str = NULL;
+		int rc = 0;
+
+		switch (get_column_id(i)) {
+		case COL_RES:
+			rc = asprintf(&str, "%s", l->desc->name);
+			break;
+		case COL_HELP:
+			rc = asprintf(&str, "%s", l->desc->help);
+			break;
+		case COL_SOFT:
+			rc = l->rlim.rlim_cur == RLIM_INFINITY ?
+				asprintf(&str, "%s", "unlimited") :
+				asprintf(&str, "%llu", (unsigned long long) l->rlim.rlim_cur);
+			break;
+		case COL_HARD:
+			rc = l->rlim.rlim_max == RLIM_INFINITY ?
+				asprintf(&str, "%s", "unlimited") :
+				asprintf(&str, "%llu", (unsigned long long) l->rlim.rlim_max);
+			break;
+		default:
+			break;
+		}
+
+		if (rc || str)
+			tt_line_set_data(line, i, str);
+	}
+}
+
+static int column_name_to_id(const char *name, size_t namesz)
+{
+	size_t i;
+
+	assert(name);
+
+	for (i = 0; i < NCOLS; i++) {
+		const char *cn = infos[i].name;
+
+		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+			return i;
+	}
+	warnx(_("unknown column: %s"), name);
+	return -1;
+}
+
+static int show_limits(struct prlimit lims[], int tt_flags, size_t n)
+{
+	int i;
+	struct tt *tt;
+
+	tt = tt_new_table(tt_flags);
+	if (!tt) {
+		warn(_("failed to initialize output table"));
+		return -1;
+	}
+
+	for (i = 0; i < ncolumns; i++) {
+		struct colinfo *col = get_column_info(i);
+
+		if (!tt_define_column(tt, col->name, col->whint, col->flags)) {
+			warnx(_("failed to initialize output column"));
+			goto done;
+		}
+	}
+
+	for (i = 0; (size_t) i < n; i++)
+		if (!lims[i].modify) /* only display old limits */
+			add_tt_line(tt, &lims[i]);
+
+	tt_print_table(tt);
+done:
+	tt_free_table(tt);
+	return 0;
+}
+
+
+static void do_prlimit(struct prlimit lims[], size_t n)
+{
+	size_t i, nshows = 0;
+
+	for (i = 0; i < n; i++) {
+		struct rlimit *new = NULL;
+
+		if (lims[i].modify)
+			new = &lims[i].rlim;
+		else
+			nshows++;
+
+		if (verbose && new) {
+			printf(_("New %s limit: "), lims[i].desc->name);
+			if (new->rlim_cur == RLIM_INFINITY)
+				printf("<%s", _("unlimited"));
+			else
+				printf("<%ju", new->rlim_cur);
+
+			if (new->rlim_max == RLIM_INFINITY)
+				printf(":%s>\n", _("unlimited"));
+			else
+				printf(":%ju>\n", new->rlim_max);
+		}
+
+		if (prlimit(pid, lims[i].desc->resource, new, &lims[i].rlim) == -1)
+			err(EXIT_FAILURE, _("failed to get resource limits for PID %d"), pid);
+	}
+
+	if (nshows)
+		show_limits(lims, 0, n);
+}
+
+
+
+static int get_range(char *str, rlim_t *soft, rlim_t *hard, int *found)
+{
+	char *end = NULL;
+
+	if (!str)
+		return 0;
+
+	*found = errno = 0;
+	*soft = *hard = RLIM_INFINITY;
+
+	if (!strcmp(str, INFINITY_STR)) {		/* <unlimited> */
+		*found |= PRLIMIT_SOFT | PRLIMIT_HARD;
+		return 0;
+
+	} else if (*str == ':') {			/* <:hard> */
+		str++;
+
+		if (strcmp(str, INFINITY_STR) != 0) {
+			*hard = strtoull(str, &end, 10);
+
+			if (errno || !end || *end || end == str)
+				return -1;
+		}
+		*found |= PRLIMIT_HARD;
+		return 0;
+
+	}
+
+	if (strncmp(str, INFINITY_STR, INFINITY_STRLEN) == 0) {
+		/* <unlimited> or <unlimited:> */
+		end = str + INFINITY_STRLEN;
+	} else {
+		/* <value> or <soft:> */
+		*hard = *soft = strtoull(str, &end, 10);
+		if (errno || !end || end == str)
+			return -1;
+	}
+
+	if (*end == ':' && !*(end + 1))			/* <soft:> */
+		*found |= PRLIMIT_SOFT;
+
+	else if (*end == ':') {				/* <soft:hard> */
+		str = end + 1;
+
+		if (!strcmp(str, INFINITY_STR))
+			*hard =  RLIM_INFINITY;
+		else {
+			end = NULL;
+			errno = 0;
+			*hard = strtoull(str, &end, 10);
+
+			if (errno || !end || *end || end == str)
+				return -1;
+		}
+		*found |= PRLIMIT_SOFT | PRLIMIT_HARD;
+
+	} else						/* <value> */
+		*found |= PRLIMIT_SOFT | PRLIMIT_HARD;
+
+	return 0;
+}
+
+
+static int parse_prlim(struct rlimit *lim, char *ops, size_t id)
+{
+	rlim_t soft, hard;
+	int found = 0;
+
+	if (get_range(ops, &soft, &hard, &found))
+		errx(EXIT_FAILURE, _("failed to parse %s limit"),
+		     prlimit_desc[id].name);
+
+	/*
+	 * If one of the limits is unknown (default value for not being passed), we need
+	 * to get the current limit and use it.
+	 * I see no other way other than using prlimit(2).
+	 */
+	if (found != (PRLIMIT_HARD | PRLIMIT_SOFT)) {
+		struct rlimit old;
+
+		if (prlimit(pid, prlimit_desc[id].resource, NULL, &old) == -1)
+			errx(EXIT_FAILURE, _("failed to get old %s limit"),
+			     prlimit_desc[id].name);
+
+		if (!(found & PRLIMIT_SOFT))
+			soft = old.rlim_cur;
+		else if (!(found & PRLIMIT_HARD))
+			hard = old.rlim_max;
+	}
+
+	if (soft > hard && (soft != RLIM_INFINITY || hard != RLIM_INFINITY))
+		errx(EXIT_FAILURE, _("the soft limit cannot exceed the ceiling value"));
+
+	lim->rlim_cur = soft;
+	lim->rlim_max = hard;
+
+	return 0;
+}
+
+/*
+ * Add a resource limit to the limits array
+ */
+static int add_prlim(char *ops, struct prlimit *lim, size_t id)
+{
+	lim->desc = &prlimit_desc[id];
+
+	if (ops) { /* planning on modifying a limit? */
+		lim->modify = 1;
+		parse_prlim(&lim->rlim, ops, id);
+	}
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	int opt;
+        size_t n = 0;
+	struct prlimit lims[MAX_RESOURCES] = { PRLIMIT_EMPTY_LIMIT };
+
+	enum {
+		VERBOSE_OPTION = CHAR_MAX + 1
+	};
+
+	static const struct option longopts[] = {
+		{ "pid",	required_argument, NULL, 'p' },
+		{ "output",     required_argument, NULL, 'o' },
+		{ "as",         optional_argument, NULL, 'v' },
+		{ "core",       optional_argument, NULL, 'c' },
+		{ "cpu",        optional_argument, NULL, 't' },
+		{ "data",       optional_argument, NULL, 'd' },
+		{ "fsize",      optional_argument, NULL, 'f' },
+		{ "locks",      optional_argument, NULL, 'x' },
+		{ "memlock",    optional_argument, NULL, 'l' },
+		{ "msgqueue",   optional_argument, NULL, 'q' },
+		{ "nice",       optional_argument, NULL, 'e' },
+		{ "nofile",     optional_argument, NULL, 'n' },
+		{ "nproc",      optional_argument, NULL, 'u' },
+		{ "rss",        optional_argument, NULL, 'm' },
+		{ "rtprio",     optional_argument, NULL, 'r' },
+		{ "rttime",     optional_argument, NULL, 'y' },
+		{ "sigpending", optional_argument, NULL, 'i' },
+		{ "stack",      optional_argument, NULL, 's' },
+		{ "version",    no_argument, NULL, 'V' },
+		{ "help",       no_argument, NULL, 'h' },
+		{ "verbose",    no_argument, NULL, VERBOSE_OPTION },
+		{ NULL, 0, NULL, 0 }
+	};
+
+	setlocale(LC_ALL, "");
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+
+	/*
+	 * Something is very wrong if this doesn't succeed,
+	 * assuming STACK is the last resource, of course.
+	 */
+	assert(MAX_RESOURCES == STACK + 1);
+
+	while((opt = getopt_long(argc, argv,
+				 "c::d::e::f::i::l::m::n::q::r::s::t::u::v::x::y::p:o:vVh",
+				 longopts, NULL)) != -1) {
+		switch(opt) {
+		case 'c':
+			add_prlim(optarg, &lims[n++], CORE);
+			break;
+		case 'd':
+			add_prlim(optarg, &lims[n++], DATA);
+			break;
+		case 'e':
+			add_prlim(optarg, &lims[n++], NICE);
+			break;
+		case 'f':
+			add_prlim(optarg, &lims[n++], FSIZE);
+			break;
+		case 'i':
+			add_prlim(optarg, &lims[n++], SIGPENDING);
+			break;
+		case 'l':
+			add_prlim(optarg, &lims[n++], MEMLOCK);
+			break;
+		case 'm':
+			add_prlim(optarg, &lims[n++], RSS);
+			break;
+		case 'n':
+			add_prlim(optarg, &lims[n++], NOFILE);
+			break;
+		case 'q':
+			add_prlim(optarg, &lims[n++], MSGQUEUE);
+			break;
+		case 'r':
+			add_prlim(optarg, &lims[n++], RTPRIO);
+			break;
+		case 's':
+			add_prlim(optarg, &lims[n++], STACK);
+			break;
+		case 't':
+			add_prlim(optarg, &lims[n++], CPU);
+			break;
+		case 'u':
+			add_prlim(optarg, &lims[n++], NPROC);
+			break;
+		case 'v':
+			add_prlim(optarg, &lims[n++], AS);
+			break;
+		case 'x':
+			add_prlim(optarg, &lims[n++], LOCKS);
+			break;
+		case 'y':
+			add_prlim(optarg, &lims[n++], RTTIME);
+			break;
+
+		case 'p':
+			if (pid) /* we only work one pid at a time */
+				errx(EXIT_FAILURE, _("only use one PID at a time"));
+
+			pid = strtol_or_err(optarg, _("cannot parse PID"));
+			break;
+		case 'h':
+			usage(stdout);
+			break;
+		case 'o':
+			ncolumns = string_to_idarray(optarg,
+						     columns, ARRAY_SIZE(columns),
+						     column_name_to_id);
+			if (ncolumns < 0)
+				return EXIT_FAILURE;
+			break;
+		case 'V':
+			printf(UTIL_LINUX_VERSION);
+			return EXIT_SUCCESS;
+		case VERBOSE_OPTION:
+			verbose++;
+			break;
+		default:
+			usage(stderr);
+			break;
+		}
+	}
+
+	if (argc == 1)
+		usage(stderr);
+
+	if (!ncolumns) {
+		/* default columns */
+		columns[ncolumns++] = COL_RES;
+		columns[ncolumns++] = COL_HELP;
+		columns[ncolumns++] = COL_SOFT;
+		columns[ncolumns++] = COL_HARD;
+	}
+
+	if (!n) {
+		/* default is to print all resources */
+		for (; n < MAX_RESOURCES; n++)
+			add_prlim(NULL, &lims[n], n);
+	}
+
+	do_prlimit(lims, n);
+
+	return EXIT_SUCCESS;
+}