/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <errno.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <limits.h>
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <libproc.h>

extern int _getgroupsbymember(const char *, gid_t[], int, int);

static int look(char *);
static int perr(char *);

static void usage(void);
static void initcred(void);

static char *command;
static char *procname;

static char *user;
static char *group;
static char *grplst;
static char *login;

static boolean_t all = B_FALSE;
static boolean_t doset = B_FALSE;
static int ngrp = -1;
static gid_t *groups;
static long ngroups_max;

static uid_t uid = (uid_t)-1;
static gid_t gid = (gid_t)-1;

int
main(int argc, char **argv)
{
        int rc = 0;
        int c;
        struct rlimit rlim;

        if ((command = strrchr(argv[0], '/')) != NULL)
                command++;
        else
                command = argv[0];

        if ((ngroups_max = sysconf(_SC_NGROUPS_MAX)) < 0)
                return (perr("sysconf(_SC_NGROUPS_MAX)"));

        opterr = 0;

        while ((c = getopt(argc, argv, "au:g:l:G:")) != EOF) {
                switch (c) {
                case 'a':
                        all = B_TRUE;
                        break;
                case 'u':
                        user = optarg;
                        doset = B_TRUE;
                        break;
                case 'g':
                        group = optarg;
                        doset = B_TRUE;
                        break;
                case 'G':
                        grplst = optarg;
                        doset = B_TRUE;
                        break;
                case 'l':
                        login = optarg;
                        doset = B_TRUE;
                        break;
                default:
                        usage();
                        /*NOTREACHED*/
                }
        }
        if (login != NULL && (user != NULL || group != NULL || grplst != NULL))
                usage();

        if (all && doset)
                usage();

        argc -= optind;
        argv += optind;

        if (argc == 0)
                usage();

        if (doset)
                initcred();

        /*
         * Make sure we'll have enough file descriptors to handle a target
         * that has many many mappings.
         */
        if (getrlimit(RLIMIT_NOFILE, &rlim) == 0) {
                rlim.rlim_cur = rlim.rlim_max;
                (void) setrlimit(RLIMIT_NOFILE, &rlim);
                (void) enable_extended_FILE_stdio(-1, -1);
        }

        while (argc-- > 0)
                rc += look(*argv++);

        return (rc > 255 ? 255 : rc);
}

static void
credupdate(prcred_t *pcr)
{
        if (uid != (uid_t)-1)
                pcr->pr_euid = pcr->pr_ruid = pcr->pr_suid = uid;
        if (gid != (gid_t)-1)
                pcr->pr_egid = pcr->pr_rgid = pcr->pr_sgid = gid;
        if (ngrp >= 0) {

                pcr->pr_ngroups = ngrp;

                (void) memcpy(pcr->pr_groups, groups, ngrp * sizeof (gid_t));
        }
}

static int
look(char *arg)
{
        struct ps_prochandle *Pr;
        static prcred_t *prcred = NULL;
        int gcode;

        procname = arg;         /* for perr() */

        if (prcred == NULL) {
                prcred = malloc(sizeof (prcred_t) +
                        (ngroups_max - 1) * sizeof (gid_t));
                if (prcred == NULL) {
                        (void) perr("malloc");
                        exit(1);
                }
        }

        if ((Pr = proc_arg_grab(arg, doset ? PR_ARG_PIDS : PR_ARG_ANY,
            PGRAB_RETAIN | PGRAB_FORCE | (doset ? 0 : PGRAB_RDONLY) |
            PGRAB_NOSTOP, &gcode)) == NULL) {
                (void) fprintf(stderr, "%s: cannot examine %s: %s\n",
                    command, arg, Pgrab_error(gcode));
                return (1);
        }

        if (Pcred(Pr, prcred, ngroups_max) == -1) {
                (void) perr("getcred");
                Prelease(Pr, 0);
                return (1);
        }

        if (doset) {
                credupdate(prcred);
                if (Psetcred(Pr, prcred) != 0) {
                        (void) perr("setcred");
                        Prelease(Pr, 0);
                        return (1);
                }
                Prelease(Pr, 0);
                return (0);
        }

        if (Pstate(Pr) == PS_DEAD)
                (void) printf("core of %d:\t", (int)Pstatus(Pr)->pr_pid);
        else
                (void) printf("%d:\t", (int)Pstatus(Pr)->pr_pid);

        if (!all &&
            prcred->pr_euid == prcred->pr_ruid &&
            prcred->pr_ruid == prcred->pr_suid)
                (void) printf("e/r/suid=%u  ", prcred->pr_euid);
        else
                (void) printf("euid=%u ruid=%u suid=%u  ",
                        prcred->pr_euid, prcred->pr_ruid, prcred->pr_suid);

        if (!all &&
            prcred->pr_egid == prcred->pr_rgid &&
            prcred->pr_rgid == prcred->pr_sgid)
                (void) printf("e/r/sgid=%u\n", prcred->pr_egid);
        else
                (void) printf("egid=%u rgid=%u sgid=%u\n",
                        prcred->pr_egid, prcred->pr_rgid, prcred->pr_sgid);

        if (prcred->pr_ngroups != 0 &&
            (all || prcred->pr_ngroups != 1 ||
            prcred->pr_groups[0] != prcred->pr_rgid)) {
                int i;

                (void) printf("\tgroups:");
                for (i = 0; i < prcred->pr_ngroups; i++)
                        (void) printf(" %u", prcred->pr_groups[i]);
                (void) printf("\n");
        }

        Prelease(Pr, 0);
        return (0);
}

static int
perr(char *s)
{
        if (s)
                (void) fprintf(stderr, "%s: ", procname);
        else
                s = procname;
        perror(s);
        return (1);
}

static void
usage(void)
{
        (void) fprintf(stderr, "usage:\t%s [-a] { pid | core } ...\n"
            "\t%s [-u user] [-g group] [-G groups] pid ...\n"
            "\t%s -l login pid ...\n"
            "  (report or modify process credentials)\n",
            command, command, command);
        exit(2);
}


static uint32_t
str2id(const char *str)
{
        unsigned long res;
        char *p;

        errno = 0;
        res = strtoul(str, &p, 0);
        if (p == str || *p != '\0' || errno != 0)
                return ((uint32_t)-1);
        else
                return ((uint32_t)res);
}

static gid_t
str2gid(const char *grnam)
{
        struct group *grp = getgrnam(grnam);
        gid_t res;

        if (grp == NULL) {
                res = (gid_t)str2id(grnam);
                if (res == (gid_t)-1) {
                        (void) fprintf(stderr, "%s: %s: unknown group"
                            " or bad gid\n",
                            command, grnam);
                        exit(1);
                }
        } else {
                res = grp->gr_gid;
        }
        return (res);
}

static void
initcred(void)
{
        struct passwd *pwd;

        if ((groups = malloc(ngroups_max * sizeof (gid_t))) == NULL) {
                (void) perr("malloc");
                exit(1);
        }

        if (login != NULL) {
                pwd = getpwnam(login);

                if (pwd == NULL) {
                        (void) fprintf(stderr, "%s: %s: unknown user\n",
                            command, login);
                        exit(1);
                }
                uid = pwd->pw_uid;
                gid = pwd->pw_gid;

                groups[0] = gid;

                ngrp = _getgroupsbymember(login, groups, (int)ngroups_max, 1);
        }

        if (user != NULL) {
                pwd = getpwnam(user);
                if (pwd == NULL) {
                        uid = (uid_t)str2id(user);
                        if (uid == (uid_t)-1) {
                                (void) fprintf(stderr, "%s: %s: unknown user"
                                    " or bad uid\n",
                                    command, user);
                                exit(1);
                        }
                } else {
                        uid = pwd->pw_uid;
                }
        }

        if (group != NULL)
                gid = str2gid(group);

        if (grplst != NULL) {
                char *cgrp;

                ngrp = 0;

                while ((cgrp = strtok(grplst, ",")) != NULL) {

                        if (ngrp >= ngroups_max) {
                                (void) fprintf(stderr, "%s: Too many groups\n",
                                    command);
                                exit(1);
                        }
                        groups[ngrp++] = str2gid(cgrp);

                        /* For iterations of strtok */
                        grplst = NULL;
                }
        }
}