/*      $OpenBSD: c_ulimit.c,v 1.29 2019/06/28 13:34:59 deraadt Exp $   */

/*
        ulimit -- handle "ulimit" builtin

        Reworked to use getrusage() and ulimit() at once (as needed on
        some schizophrenic systems, eg, HP-UX 9.01), made argument parsing
        conform to at&t ksh, added autoconf support.  Michael Rendell, May, '94

        Eric Gisin, September 1988
        Adapted to PD KornShell. Removed AT&T code.

        last edit:      06-Jun-1987     D A Gwyn

        This started out as the BRL UNIX System V system call emulation
        for 4.nBSD, and was later extended by Doug Kingston to handle
        the extended 4.nBSD resource limits.  It now includes the code
        that was originally under case SYSULIMIT in source file "xec.c".
*/

#include <sys/resource.h>

#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <string.h>

#include "sh.h"

#define SOFT    0x1
#define HARD    0x2

struct limits {
        const char *name;
        int     resource;       /* resource to get/set */
        int     factor;         /* multiply by to get rlim_{cur,max} values */
        char    option;         /* option character (-d, -f, ...) */
};

static void print_ulimit(const struct limits *, int);
static int set_ulimit(const struct limits *, const char *, int);

int
c_ulimit(char **wp)
{
        static const struct limits limits[] = {
                /* Do not use options -H, -S or -a or change the order. */
                { "time(cpu-seconds)", RLIMIT_CPU, 1, 't' },
                { "file(blocks)", RLIMIT_FSIZE, 512, 'f' },
                { "coredump(blocks)", RLIMIT_CORE, 512, 'c' },
                { "data(kbytes)", RLIMIT_DATA, 1024, 'd' },
                { "stack(kbytes)", RLIMIT_STACK, 1024, 's' },
                { "lockedmem(kbytes)", RLIMIT_MEMLOCK, 1024, 'l' },
                { "memory(kbytes)", RLIMIT_RSS, 1024, 'm' },
                { "nofiles(descriptors)", RLIMIT_NOFILE, 1, 'n' },
                { "processes", RLIMIT_NPROC, 1, 'p' },
                { NULL }
        };
        const char      *options = "HSat#f#c#d#s#l#m#n#p#";
        int             how = SOFT | HARD;
        const struct limits     *l;
        int             optc, all = 0;

        /* First check for -a, -H and -S. */
        while ((optc = ksh_getopt(wp, &builtin_opt, options)) != -1)
                switch (optc) {
                case 'H':
                        how = HARD;
                        break;
                case 'S':
                        how = SOFT;
                        break;
                case 'a':
                        all = 1;
                        break;
                case '?':
                        return 1;
                default:
                        break;
                }

        if (wp[builtin_opt.optind] != NULL) {
                bi_errorf("usage: ulimit [-acdfHlmnpSst] [value]");
                return 1;
        }

        /* Then parse and act on the actual limits, one at a time */
        ksh_getopt_reset(&builtin_opt, GF_ERROR);
        while ((optc = ksh_getopt(wp, &builtin_opt, options)) != -1)
                switch (optc) {
                case 'a':
                case 'H':
                case 'S':
                        break;
                case '?':
                        return 1;
                default:
                        for (l = limits; l->name && l->option != optc; l++)
                                ;
                        if (!l->name) {
                                internal_warningf("%s: %c", __func__, optc);
                                return 1;
                        }
                        if (builtin_opt.optarg) {
                                if (set_ulimit(l, builtin_opt.optarg, how))
                                        return 1;
                        } else
                                print_ulimit(l, how);
                        break;
                }

        wp += builtin_opt.optind;

        if (all) {
                for (l = limits; l->name; l++) {
                        shprintf("%-20s ", l->name);
                        print_ulimit(l, how);
                }
        } else if (builtin_opt.optind == 1) {
                /* No limit specified, use file size */
                l = &limits[1];
                if (wp[0] != NULL) {
                        if (set_ulimit(l, wp[0], how))
                                return 1;
                        wp++;
                } else {
                        print_ulimit(l, how);
                }
        }

        return 0;
}

static int
set_ulimit(const struct limits *l, const char *v, int how)
{
        rlim_t          val = 0;
        struct rlimit   limit;

        if (strcmp(v, "unlimited") == 0)
                val = RLIM_INFINITY;
        else {
                int64_t rval;

                if (!evaluate(v, &rval, KSH_RETURN_ERROR, false))
                        return 1;
                /*
                 * Avoid problems caused by typos that evaluate misses due
                 * to evaluating unset parameters to 0...
                 * If this causes problems, will have to add parameter to
                 * evaluate() to control if unset params are 0 or an error.
                 */
                if (!rval && !digit(v[0])) {
                        bi_errorf("invalid limit: %s", v);
                        return 1;
                }
                val = (rlim_t)rval * l->factor;
        }

        getrlimit(l->resource, &limit);
        if (how & SOFT)
                limit.rlim_cur = val;
        if (how & HARD)
                limit.rlim_max = val;
        if (setrlimit(l->resource, &limit) == -1) {
                if (errno == EPERM)
                        bi_errorf("-%c exceeds allowable limit", l->option);
                else
                        bi_errorf("bad -%c limit: %s", l->option,
                            strerror(errno));
                return 1;
        }
        return 0;
}

static void
print_ulimit(const struct limits *l, int how)
{
        rlim_t          val = 0;
        struct rlimit   limit;

        getrlimit(l->resource, &limit);
        if (how & SOFT)
                val = limit.rlim_cur;
        else if (how & HARD)
                val = limit.rlim_max;
        if (val == RLIM_INFINITY)
                shprintf("unlimited\n");
        else {
                val /= l->factor;
                shprintf("%" PRIi64 "\n", (int64_t) val);
        }
}