githubmirror/lsof

src/arg.c
2 193 строки66 KB
Bjorn Helgaas
Fix typos (#313)
02 апр 2024, 04:36
02 апр 2024, 04:36ceb40c3
/*
 * arg.c - common argument processing support functions for lsof
 */

/*
 * Copyright 1994 Purdue Research Foundation, West Lafayette, Indiana
 * 47907.  All rights reserved.
 *
 * Written by Victor A. Abell
 *
 * This software is not subject to any license of the American Telephone
 * and Telegraph Company or the Regents of the University of California.
 *
 * Permission is granted to anyone to use this software for any purpose on
 * any computer system, and to alter it and redistribute it freely, subject
 * to the following restrictions:
 *
 * 1. Neither the authors nor Purdue University are responsible for any
 *    consequences of the use of this software.
 *
 * 2. The origin of this software must not be misrepresented, either by
 *    explicit claim or by omission.  Credit to the authors and Purdue
 *    University must appear in documentation and sources.
 *
 * 3. Altered versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 *
 * 4. This notice may not be removed or altered.
 */

#include "common.h"
#include "cli.h"
#include "lsof.h"
#include <limits.h>

/*
 * Local definitions
 */

#define CMDRXINCR 32 /* CmdRx[] allocation increment */

/*
 * Local static variables
 */

/*
 * Local function prototypes
 */

static int ckfd_range(struct lsof_context *ctx, char *first, char *dash,
                      char *last, int *lo, int *hi);
static int enter_fd_lst(struct lsof_context *ctx, char *nm, int lo, int hi,
                        int excl);
static int enter_nwad(struct lsof_context *ctx, struct nwad *n, int sp, int ep,
                      char *s, struct hostent *he);
static struct hostent *lkup_hostnm(char *hn, struct nwad *n);
static char *isIPv4addr(char *hn, unsigned char *a, int al);

/*
 * ckfd_range() - check fd range
 */

static int ckfd_range(struct lsof_context *ctx, /* context */
                      char *first,              /* starting character */
                      char *dash,               /* '-' location */
                      char *last,               /* '\0' location */
                      int *lo,                  /* returned low value */
                      int *hi)                  /* returned high value */
{
    char *cp;
    /*
     * See if the range character pointers make sense.
     */
    if (first >= dash || dash >= last) {
        (void)fprintf(stderr, "%s: illegal FD range for -d: ", Pn);
        safestrprt(first, stderr, 1);
        return (1);
    }
    /*
     * Assemble and check the high and low values.
     */
    for (cp = first, *lo = 0; *cp && cp < dash; cp++) {
        if (!isdigit((unsigned char)*cp)) {

        FD_range_nondigit:

            (void)fprintf(stderr, "%s: non-digit in -d FD range: ", Pn);
            safestrprt(first, stderr, 1);
            return (1);
        }
        *lo = (*lo * 10) + (int)(*cp - '0');
    }
    for (cp = dash + 1, *hi = 0; *cp && cp < last; cp++) {
        if (!isdigit((unsigned char)*cp))
            goto FD_range_nondigit;
        *hi = (*hi * 10) + (int)(*cp - '0');
    }
    if (*lo >= *hi) {
        (void)fprintf(stderr, "%s: -d FD range's low >= its high: ", Pn);
        safestrprt(first, stderr, 1);
        return (1);
    }
    return (0);
}

/*
 * ck_file_arg() - check file arguments
 */

int ck_file_arg(struct lsof_context *ctx, int i, /* first file argument index */
                int ac,                          /* argument count */
                char *av[],                      /* argument vector */
                int fv,           /* Ffilesys value (real or temporary) */
                int rs,           /* Readlink() status if argument count == 1:
                                   *	0 = undone; 1 = done */
                struct stat *sbp, /* if non-NULL, pointer to stat(2) buffer
                                   * when argument count == 1 */
                int accept_deleted_file) /* if non-zero, don't report an error
                                          * even when the file doesn't exist. */
{
    char *ap, *fnm, *fsnm, *path;
    short err = 0;
    int fsm, ftype, j, k;
    MALLOC_S l;
    struct mounts *mp;
    static struct mounts **mmp = (struct mounts **)NULL;
    int mx, nm;
    static int nma = 0;
    struct stat sb;
    struct sfile *sfp;
    short ss = 0;

#if defined(CKFA_EXPDEV)
    dev_t dev, rdev;
#endif /* defined(CKFA_EXPDEV) */

#if defined(HASPROCFS)
    unsigned char ad, an;
    int pfsnl = -1;
    pid_t pid;
    struct procfsid *pfi;
#endif /* defined(HASPROCFS) */

    /*
     * Loop through arguments.
     */
    for (; i < ac; i++) {
        if (rs && (ac == 1) && (i == 0))
            path = av[i];
        else {
            if (!(path = Readlink(ctx, av[i]))) {
                ErrStat = 1;
                continue;
            }
        }
        /*
         * Remove terminating `/' characters from paths longer than one.
         */
        j = k = strlen(path);
        while ((k > 1) && (path[k - 1] == '/')) {
            k--;
        }
        if (k < j) {
            if (path != av[i])
                path[k] = '\0';
            else {
                if (!(ap = (char *)malloc((MALLOC_S)(k + 1)))) {
                    (void)fprintf(stderr, "%s: no space for copy of %s\n", Pn,
                                  path);
                    Error(ctx);
                }
                (void)strncpy(ap, path, k);
                ap[k] = '\0';
                path = ap;
            }
        }
        /*
         * Check for file system argument.
         */
        for (ftype = 1, mp = readmnt(ctx), nm = 0; (fv != 1) && mp;
             mp = mp->next) {
            fsm = 0;
            if (strcmp(mp->dir, path) == 0)
                fsm++;
            else if (fv == 2 || (mp->fs_mode & S_IFMT) == S_IFBLK) {
                if (mp->fsnmres && strcmp(mp->fsnmres, path) == 0)
                    fsm++;
            }
            if (!fsm)
                continue;
            ftype = 0;
            /*
             * Skip duplicates.
             */
            for (mx = 0; mx < nm; mx++) {
                if (strcmp(mp->dir, mmp[mx]->dir) == 0 &&
                    mp->dev == mmp[mx]->dev && mp->rdev == mmp[mx]->rdev &&
                    mp->inode == mmp[mx]->inode)
                    break;
            }
            if (mx < nm)
                continue;
            /*
             * Allocate space for and save another mount point match and
             * the type of match -- directory name (mounted) or file system
             * name (mounted-on).
             */
            if (nm >= nma) {
                nma += 5;
                l = (MALLOC_S)(nma * sizeof(struct mounts *));
                if (mmp)
                    mmp = (struct mounts **)realloc((MALLOC_P *)mmp, l);
                else
                    mmp = (struct mounts **)malloc(l);
                if (!mmp) {
                    (void)fprintf(stderr, "%s: no space for mount pointers\n",
                                  Pn);
                    Error(ctx);
                }
            }
            mmp[nm++] = mp;
        }
        if (fv == 2 && nm == 0) {
            if (!accept_deleted_file) {
                (void)fprintf(stderr, "%s: not a file system: ", Pn);
                safestrprt(av[i], stderr, 1);
            }
            ErrStat = 1;
            continue;
        }
        /*
         * Loop through the file system matches.  If there were none, make one
         * pass through the loop, using simply the path name.
         */
        mx = 0;
        do {

            /*
             * Allocate an sfile structure and fill in the type and link.
             */
            if (!(sfp = (struct sfile *)malloc(sizeof(struct sfile)))) {
                (void)fprintf(stderr, "%s: no space for files\n", Pn);
                Error(ctx);
            }
            sfp->next = Sfile;
            Sfile = sfp;
            sfp->f = 0;
            if ((sfp->type = ftype)) {

                /*
                 * For a non-file system path, use the path as the file name
                 * and set a NULL file system name.
                 */
                fnm = path;
                fsnm = (char *)NULL;
                /*
                 * Stat the path to obtain its characteristics.
                 */
                if (sbp && (ac == 1))
                    sb = *sbp;
                else {
                    if (statsafely(ctx, fnm, &sb) != 0) {
                        int en = errno;
                        if (!accept_deleted_file) {
                            (void)fprintf(stderr, "%s: status error on ", Pn);
                            safestrprt(fnm, stderr, 0);
                            (void)fprintf(stderr, ": %s\n", strerror(en));
                        }
                        Sfile = sfp->next;
                        (void)free((FREE_P *)sfp);
                        ErrStat = 1;
                        continue;
                    }

#if defined(HASSPECDEVD)
                    (void)HASSPECDEVD(ctx, fnm, &sb);
#endif /* defined(HASSPECDEVD) */
                }
                sfp->i = (INODETYPE)sb.st_ino;
                sfp->mode = sb.st_mode & S_IFMT;

#if defined(CKFA_EXPDEV)
                /*
                 * Expand device numbers before saving, so that they match the
                 * already-expanded local mount info table device numbers.
                 * (This is an EP/IX 2.1.1 and above artifact.)
                 */
                sfp->dev = expdev(sb.st_dev);
                sfp->rdev = expdev(sb.st_rdev);
#else  /* !defined(CKFA_EXPDEV) */
                sfp->dev = sb.st_dev;
                sfp->rdev = sb.st_rdev;
#endif /* defined(CKFA_EXPDEV) */

#if defined(CKFA_MPXCHAN)
                /*
                 * Save a (possible) multiplexed channel number.  (This is an
                 * AIX artifact.)
                 */
                sfp->ch = getchan(path);
#endif /* defined(CKFA_MPXCHAN) */

            } else {

#if defined(SAVE_MP_IN_SFILE)
                sfp->mp = mp = mmp[mx++];
#else  /* !defined(SAVE_MP_IN_SFILE) */
                mp = mmp[mx++];
#endif /* defined(SAVE_MP_IN_SFILE) */

                ss++;

#if defined(HASPROCFS)
                /*
                 * If this is a /proc file system, set the search flag and
                 * abandon the sfile entry.
                 */
                if (mp == Mtprocfs) {
                    Sfile = sfp->next;
                    (void)free((FREE_P *)sfp);
                    Procsrch = 1;
                    continue;
                }
#endif /* defined(HASPROCFS) */

                /*
                 * Derive file name and file system name for a mount point.
                 *
                 * Save the device numbers, inode number, and modes.
                 */
                fnm = mp->dir;
                fsnm = mp->fsname;
                sfp->dev = mp->dev;
                sfp->rdev = mp->rdev;
                sfp->i = mp->inode;
                sfp->mode = mp->mode & S_IFMT;
            }
            ss = 1; /* indicate a "safe" stat() */
                    /*
                     * Store the file name and file system name pointers in the sfile
                     * structure, allocating space as necessary.
                     */
            if (!fnm || fnm == path) {
                sfp->name = fnm;

#if defined(HASPROCFS)
                an = 0;
#endif /* defined(HASPROCFS) */

            } else {
                if (!(sfp->name = mkstrcpy(fnm, (MALLOC_S *)NULL))) {
                    (void)fprintf(stderr, "%s: no space for file name: ", Pn);
                    safestrprt(fnm, stderr, 1);
                    Error(ctx);
                }

#if defined(HASPROCFS)
                an = 1;
#endif /* defined(HASPROCFS) */
            }
            if (!fsnm || fsnm == path) {
                sfp->devnm = fsnm;

#if defined(HASPROCFS)
                ad = 0;
#endif /* defined(HASPROCFS) */

            } else {
                if (!(sfp->devnm = mkstrcpy(fsnm, (MALLOC_S *)NULL))) {
                    (void)fprintf(stderr,
                                  "%s: no space for file system name: ", Pn);
                    safestrprt(fsnm, stderr, 1);
                    Error(ctx);
                }

#if defined(HASPROCFS)
                ad = 1;
#endif /* defined(HASPROCFS) */
            }
            if (!(sfp->aname = mkstrcpy(av[i], (MALLOC_S *)NULL))) {
                (void)fprintf(stderr,
                              "%s: no space for argument file name: ", Pn);
                safestrprt(av[i], stderr, 1);
                Error(ctx);
            }

#if defined(HASPROCFS)
            /*
             * See if this is an individual member of a proc file system.
             */
            if (!Mtprocfs || Procsrch)
                continue;

#    if defined(HASFSTYPE) && HASFSTYPE == 1
            if (strcmp(sb.st_fstype, HASPROCFS) != 0)
                continue;
#    endif /* defined(HASFSTYPE) && HASFSTYPE==1 */

            if (pfsnl == -1)
                pfsnl = strlen(Mtprocfs->dir);
            if (!pfsnl)
                continue;
            if (strncmp(Mtprocfs->dir, path, pfsnl) != 0)
                continue;
            if (path[pfsnl] != '/')

#    if defined(HASPINODEN)
                pid = 0;
#    else  /* !defined(HASPINODEN) */
                continue;
#    endif /* defined(HASPINODEN) */

            else {
                for (j = pfsnl + 1; path[j]; j++) {
                    if (!isdigit((unsigned char)path[j]))
                        break;
                }
                if (path[j] || (j - pfsnl - 1) < 1 ||
                    (sfp->mode & S_IFMT) != S_IFREG)

#    if defined(HASPINODEN)
                    pid = 0;
#    else  /* !defined(HASPINODEN) */
                    continue;
#    endif /* defined(HASPINODEN) */

                else
                    pid = atoi(&path[pfsnl + 1]);
            }
            if (!(pfi = (struct procfsid *)malloc(
                      (MALLOC_S)sizeof(struct procfsid)))) {
                (void)fprintf(stderr, "%s: no space for %s ID: ", Pn,
                              Mtprocfs->dir);
                safestrprt(path, stderr, 1);
                Error(ctx);
            }
            pfi->pid = pid;
            pfi->f = 0;
            pfi->nm = sfp->aname;
            pfi->next = Procfsid;
            Procfsid = pfi;

#    if defined(HASPINODEN)
            pfi->inode = (INODETYPE)sfp->i;
#    endif /* defined(HASPINODEN) */

            /*
             * Abandon the Sfile entry, lest it be used in is_file_named().
             */
            Sfile = sfp->next;
            if (ad)
                (void)free((FREE_P *)sfp->devnm);
            if (an)
                (void)free((FREE_P *)sfp->name);
            (void)free((FREE_P *)sfp);
#endif /* defined(HASPROCFS) */

        } while (mx < nm);
    }

    if (accept_deleted_file) {
        if (!ss && ErrStat == 0)
            err = 1;
        if (ErrStat)
            ErrStat = 0;
    } else if (!ss) {
        err = 1;
    }
    return ((int)err);
}

#if defined(HASDCACHE)
/*
 * ctrl_dcache() - enter device cache control
 */

int ctrl_dcache(struct lsof_context *ctx, /* context */
                char *c)                  /* control string */
{
    int rc = 0;

    if (!c) {
        (void)fprintf(stderr, "%s: no device cache option control string\n",
                      Pn);
        return (1);
    }
    /*
     * Decode argument function character.
     */
    switch (*c) {
    case '?':
        if (*(c + 1) != '\0') {
            (void)fprintf(stderr, "%s: nothing should follow -D?\n", Pn);
            return (1);
        }
        DChelp = 1;
        return (0);
    case 'b':
    case 'B':
        if (Setuidroot

#    if !defined(WILLDROPGID)
            || Myuid
#    endif /* !defined(WILLDROPGID) */

        )
            rc = 1;
        else
            DCstate = 1;
        break;
    case 'r':
    case 'R':
        if (Setuidroot && *(c + 1))
            rc = 1;
        else
            DCstate = 2;
        break;
    case 'u':
    case 'U':
        if (Setuidroot

#    if !defined(WILLDROPGID)
            || Myuid
#    endif /* !defined(WILLDROPGID) */

        )
            rc = 1;
        else
            DCstate = 3;
        break;
    case 'i':
    case 'I':
        if (*(c + 1) == '\0') {
            DCstate = 0;
            return (0);
        }
        /* fall through */
    default:
        (void)fprintf(stderr, "%s: unknown -D option: ", Pn);
        safestrprt(c, stderr, 1);
        return (1);
    }
    if (rc) {
        (void)fprintf(stderr, "%s: -D option restricted to root: ", Pn);
        safestrprt(c, stderr, 1);
        return (1);
    }
    /*
     * Skip to optional path name and save it.
     */
    for (c++; *c && (*c == ' ' || *c == '\t'); c++)
        ;
    if (strlen(c)) {
        if (!(DCpathArg = mkstrcpy(c, (MALLOC_S *)NULL))) {
            (void)fprintf(stderr, "%s: no space for -D path: ", Pn);
            safestrprt(c, stderr, 1);
            Error(ctx);
        }
    }
    return (0);
}
#endif /* defined(HASDCACHE) */


#if defined(HASEOPT)
/*
 * enter_efsys() -- enter path of file system whose kernel blocks are to be
 *		    eliminated
 */

int enter_efsys(struct lsof_context *ctx, /* context */
                char *e,                  /* file system path */
                int rdlnk)                /* avoid readlink(2) if non-zero */
{
    char *ec;         /* pointer to copy of path */
    efsys_list_t *ep; /* file system path list pointer */
    int i;            /* temporary index */
    char *path;       /* Readlink() of file system path */

    if (!e || (*e != '/')) {
        if (!Fwarn)
            (void)fprintf(stderr,
                          "%s: -e not followed by a file system path: \"%s\"\n",
                          Pn, e);
        return (1);
    }
    if (!(ec = mkstrcpy(e, (MALLOC_S *)NULL))) {
        (void)fprintf(stderr, "%s: no space for -e string: ", Pn);
        safestrprt(e, stderr, 1);
        Error(ctx);
    }
    if (rdlnk)
        path = ec;
    else {
        if (!(path = Readlink(ctx, ec)))
            return (1);
    }
    /*
     * Remove terminating `/' characters from paths longer than one.
     */
    for (i = (int)strlen(path); (i > 1) && (path[i - 1] == '/'); i--) {
        path[i - 1] = '\0';
    }
    /*
     * Enter file system path on list, avoiding duplicates.
     */
    for (ep = Efsysl; ep; ep = ep->next) {
        if (!strcmp(ep->path, path)) {
            (void)free((FREE_P *)path);
            return (0);
        }
    }
    if (!(ep = (efsys_list_t *)malloc((MALLOC_S)(sizeof(efsys_list_t))))) {
        (void)fprintf(stderr, "%s: no space for \"-e %s\" entry\n", Pn, e);
        Error(ctx);
    }
    ep->path = path;
    ep->pathl = i;
    ep->rdlnk = rdlnk;
    ep->mp = (struct mounts *)NULL;
    ep->next = Efsysl;
    Efsysl = ep;
    return (0);
}
#endif /* defined(HASEOPT) */

/*
 * enter_fd() - enter file descriptor list for searching
 */

int enter_fd(struct lsof_context *ctx, /* context */
             char *f)                  /* file descriptor list pointer */
{
    char c, *cp1, *cp2, *dash;
    int err, excl, hi, lo;
    char *fc;
    /*
     *  Check for non-empty list and make a copy.
     */
    if (!f || (strlen(f) + 1) < 2) {
        (void)fprintf(stderr, "%s: no file descriptor specified\n", Pn);
        return (1);
    }
    if (!(fc = mkstrcpy(f, (MALLOC_S *)NULL))) {
        (void)fprintf(stderr, "%s: no space for fd string: ", Pn);
        safestrprt(f, stderr, 1);
        Error(ctx);
    }
    /*
     * Isolate each file descriptor in the comma-separated list, then enter it
     * in the file descriptor string list.  If a descriptor has the form:
     *
     *	[0-9]+-[0-9]+
     *
     * treat it as an ascending range of file descriptor numbers.
     *
     * Accept a leading '^' as an excusion on match.
     */
    for (cp1 = fc, err = 0; *cp1;) {
        if (*cp1 == '^') {
            excl = 1;
            cp1++;
        } else
            excl = 0;
        for (cp2 = cp1, dash = (char *)NULL; *cp2 && *cp2 != ','; cp2++) {
            if (*cp2 == '-')
                dash = cp2;
        }
        if ((c = *cp2) != '\0')
            *cp2 = '\0';
        if (cp2 > cp1) {
            if (dash) {
                if (ckfd_range(ctx, cp1, dash, cp2, &lo, &hi))
                    err = 1;
                else {
                    if (enter_fd_lst(ctx, (char *)NULL, lo, hi, excl))
                        err = 1;
                }
            } else {
                if (enter_fd_lst(ctx, cp1, 0, 0, excl))
                    err = 1;
            }
        }
        if (c == '\0')
            break;
        cp1 = cp2 + 1;
    }
    (void)free((FREE_P *)fc);
    return (err);
}

/*
 * enter_fd_lst() - make an entry in the FD list, Fdl
 */

static int enter_fd_lst(struct lsof_context *ctx, /* context */
                        char *nm,                 /* FD name (none if NULL) */
                        int lo,   /* FD low boundary (if nm NULL) */
                        int hi,   /* FD high boundary (if nm NULL) */
                        int excl) /* exclusion on match */
{
    char buf[256], *cp;
    int n;
    struct fd_lst *f, *ft;
    /*
     * Don't allow a mixture of exclusions and inclusions.
     */
    if (FdlTy >= 0) {
        if (FdlTy != excl) {
            if (!Fwarn) {

                /*
                 * If warnings are enabled, report a mixture.
                 */
                if (nm) {
                    (void)snpf(buf, sizeof(buf) - 1, "%s%s", excl ? "^" : "",
                               nm);
                } else {
                    if (lo != hi) {
                        (void)snpf(buf, sizeof(buf) - 1, "%s%d-%d",
                                   excl ? "^" : "", lo, hi);
                    } else {
                        (void)snpf(buf, sizeof(buf) - 1, "%s%d",
                                   excl ? "^" : "", lo);
                    }
                }
                buf[sizeof(buf) - 1] = '\0';
                (void)fprintf(stderr, "%s: %s in an %s -d list: %s\n", Pn,
                              excl ? "exclude" : "include",
                              FdlTy ? "exclude" : "include", buf);
            }
            return (1);
        }
    }
    /*
     * Allocate an fd_lst entry.
     */
    if (!(f = (struct fd_lst *)malloc((MALLOC_S)sizeof(struct fd_lst)))) {
        (void)fprintf(stderr, "%s: no space for FD list entry\n", Pn);
        Error(ctx);
    }
    if (nm) {

        /*
         * Process an FD name.  First see if it contains only digits; if it
         * does, convert them to an integer and set the low and high
         * boundaries to the result.
         *
         * If the name has a non-digit, store it as a string, and set the
         * boundaries to impossible values (i.e., low > high).
         */
        for (cp = nm, n = 0; *cp; cp++) {
            if (!isdigit((unsigned char)*cp))
                break;
            n = (n * 10) + (int)(*cp - '0');
        }
        if (*cp) {
            lo = 1;
            hi = 0;
            if (strcmp(nm, "unk") == 0) {
                f->fd_type = LSOF_FD_UNKNOWN;
            } else if (strcmp(nm, "cwd") == 0) {
                f->fd_type = LSOF_FD_CWD;
            } else if (strcmp(nm, "err") == 0) {
                f->fd_type = LSOF_FD_ERROR;
            } else if (strcmp(nm, "NOFD") == 0) {
                f->fd_type = LSOF_FD_NOFD;
            } else if (strcmp(nm, "rtd") == 0) {
                f->fd_type = LSOF_FD_ROOT_DIR;
            } else if (strcmp(nm, "pd") == 0) {
                f->fd_type = LSOF_FD_PARENT_DIR;
            } else if (strcmp(nm, "txt") == 0) {
                f->fd_type = LSOF_FD_PROGRAM_TEXT;
            } else if (strcmp(nm, "ltx") == 0) {
                f->fd_type = LSOF_FD_LIBRARY_TEXT;
            } else if (strcmp(nm, "mem") == 0) {
                f->fd_type = LSOF_FD_MEMORY;
            } else if (strcmp(nm, "DEL") == 0) {
                f->fd_type = LSOF_FD_DELETED;
            } else if (strcmp(nm, "fp") == 0) {
                f->fd_type = LSOF_FD_FILEPORT;
            } else if (strcmp(nm, "twd") == 0) {
                f->fd_type = LSOF_FD_TASK_CWD;
            } else if (strcmp(nm, "ctty") == 0) {
                f->fd_type = LSOF_FD_CTTY;
            } else if (strcmp(nm, "jd.") == 0) {
                f->fd_type = LSOF_FD_JAIL_DIR;
            } else if (strcmp(nm, "v86") == 0) {
                f->fd_type = LSOF_FD_VIRTUAL_8086;
            } else if (strcmp(nm, "m86") == 0) {
                f->fd_type = LSOF_FD_MERGE_386;
            } else if (strcmp(nm, "mmap") == 0) {
                f->fd_type = LSOF_FD_MMAP_DEVICE;
            } else if (strcmp(nm, "fd") == 0) {
                /* pseudo fd type meaning whole range of fd */
                f->fd_type = LSOF_FD_NUMERIC;
                hi = INT_MAX;
                lo = 0;
            } else {
                (void)fprintf(stderr,
                              "%s: invalid fd type given in -d option\n", Pn);
                Error(ctx);
                return (1);
            }
        } else {
            f->fd_type = LSOF_FD_NUMERIC;
            lo = hi = n;
        }
    } else
        f->fd_type = LSOF_FD_NUMERIC;
    /*
     * Skip duplicates.
     */
    for (ft = Fdl; ft; ft = ft->next) {
        if (ft->fd_type != f->fd_type)
            continue;
        if (ft->fd_type == LSOF_FD_NUMERIC) {
            if ((lo != ft->lo) || (hi != ft->hi))
                continue;
        }
        (void)free((FREE_P *)f);
        return (0);
    }
    /*
     * Complete the fd_lst entry and link it to the head of the chain.
     */
    f->hi = hi;
    f->lo = lo;
    f->next = Fdl;
    Fdl = f;
    FdlTy = excl;
    return (0);
}

/*
 * enter_dir() - enter the files of a directory for searching
 */

#define EDDEFFNL 128 /* default file name length */

int enter_dir(struct lsof_context *ctx, /* context */
              char *d,                  /* directory path name pointer */
              int descend)              /* subdirectory descend flag:
                                         *	0 = don't descend
                                         *	1 = descend */
{
    char *av[2];
    dev_t ddev;
    DIR *dfp;
    char *dn = (char *)NULL;
    MALLOC_S dnl, dnamlen;
    struct DIRTYPE *dp;
    int en, sl;
    int fct = 0;
    char *fp = (char *)NULL;
    MALLOC_S fpl = (MALLOC_S)0;
    MALLOC_S fpli = (MALLOC_S)0;
    struct stat sb;
    /*
     * Check the directory path; reduce symbolic links; stat(2) it; make sure
     * it's really a directory.
     */
    if (!d || !*d || *d == '+' || *d == '-') {
        if (!Fwarn)
            (void)fprintf(stderr, "%s: +d not followed by a directory path\n",
                          Pn);
        return (1);
    }
    if (!(dn = Readlink(ctx, d)))
        return (1);
    if (statsafely(ctx, dn, &sb)) {
        if (!Fwarn) {
            en = errno;
            (void)fprintf(stderr, "%s: WARNING: can't stat(", Pn);
            safestrprt(dn, stderr, 0);
            (void)fprintf(stderr, "): %s\n", strerror(en));
        }
        if (dn && dn != d) {
            (void)free((FREE_P *)dn);
            dn = (char *)NULL;
        }
        return (1);
    }
    if ((sb.st_mode & S_IFMT) != S_IFDIR) {
        if (!Fwarn) {
            (void)fprintf(stderr, "%s: WARNING: not a directory: ", Pn);
            safestrprt(dn, stderr, 1);
        }
        if (dn && dn != d) {
            (void)free((FREE_P *)dn);
            dn = (char *)NULL;
        }
        return (1);
    }

#if defined(HASSPECDEVD)
    (void)HASSPECDEVD(ctx, dn, &sb);
#endif /* defined(HASSPECDEVD) */

    ddev = sb.st_dev;
    /*
     * Stack the directory and record it in Sfile for searching.
     */
    Dstkn = Dstkx = 0;
    Dstk = (char **)NULL;
    (void)stkdir(ctx, dn);
    av[0] = (dn == d) ? mkstrcpy(dn, (MALLOC_S *)NULL) : dn;
    av[1] = (char *)NULL;
    dn = (char *)NULL;
    if (!ck_file_arg(ctx, 0, 1, av, 1, 1, &sb, 0)) {
        av[0] = (char *)NULL;
        fct++;
    }
    /*
     * Unstack the next directory and examine it.
     */
    while (--Dstkx >= 0) {
        if (!(dn = Dstk[Dstkx]))
            continue;
        Dstk[Dstkx] = (char *)NULL;
        /*
         * Open the directory path and prepare its name for use with the
         * files in the directory.
         */
        if (!(dfp = OpenDir(dn))) {
            if (!Fwarn) {
                if ((en = errno) != ENOENT) {
                    (void)fprintf(stderr, "%s: WARNING: can't opendir(", Pn);
                    safestrprt(dn, stderr, 0);
                    (void)fprintf(stderr, "): %s\n", strerror(en));
                }
            }
            (void)free((FREE_P *)dn);
            dn = (char *)NULL;
            continue;
        }
        dnl = strlen(dn);
        sl = ((dnl > 0) && (*(dn + dnl - 1) == '/')) ? 0 : 1;
        /*
         * Define space for possible addition to the directory path.
         */
        fpli = (MALLOC_S)(dnl + sl + EDDEFFNL + 1);
        if ((int)fpli > (int)fpl) {
            fpl = fpli;
            if (!fp)
                fp = (char *)malloc(fpl);
            else
                fp = (char *)realloc(fp, fpl);
            if (!fp) {
                (void)fprintf(
                    stderr,
                    "%s: no space for path to entries in directory: %s\n", Pn,
                    dn);
                Error(ctx);
            }
        }
        (void)snpf(fp, (size_t)fpl, "%s%s", dn, sl ? "/" : "");
        (void)free((FREE_P *)dn);
        dn = (char *)NULL;
        /*
         * Read the contents of the directory.
         */
        for (dp = ReadDir(dfp); dp; dp = ReadDir(dfp)) {

            /*
             * Skip: entries with no inode number;
             *	     entries with a zero length name;
             *	     ".";
             *	     and "..".
             */
            if (!dp->d_ino)
                continue;

#if defined(HASDNAMLEN)
            dnamlen = (MALLOC_S)dp->d_namlen;
#else  /* !defined(HASDNAMLEN) */
            dnamlen = (MALLOC_S)strlen(dp->d_name);
#endif /* defined(HASDNAMLEN) */

            if (!dnamlen)
                continue;
            if (dnamlen <= 2 && dp->d_name[0] == '.') {
                if (dnamlen == 1)
                    continue;
                if (dp->d_name[1] == '.')
                    continue;
            }
            /*
             * Form the entry's path name.
             */
            fpli = (MALLOC_S)(dnamlen - (fpl - dnl - sl - 1));
            if ((int)fpli > 0) {
                fpl += fpli;
                if (!(fp = (char *)realloc(fp, fpl))) {
                    (void)fprintf(stderr, "%s: no space for: ", Pn);
                    safestrprt(dn, stderr, 0);
                    putc('/', stderr);
                    safestrprtn(dp->d_name, dnamlen, stderr, 1);
                    Error(ctx);
                }
            }
            (void)strncpy(fp + dnl + sl, dp->d_name, dnamlen);
            fp[dnl + sl + dnamlen] = '\0';
            /*
             * Lstatsafely() the entry; complain if that fails.
             *
             * Stack entries that represent subdirectories.
             */
            if (lstatsafely(ctx, fp, &sb)) {
                if ((en = errno) != ENOENT) {
                    if (!Fwarn) {
                        (void)fprintf(stderr, "%s: WARNING: can't lstat(", Pn);
                        safestrprt(fp, stderr, 0);
                        (void)fprintf(stderr, "): %s\n", strerror(en));
                    }
                }
                continue;
            }

#if defined(HASSPECDEVD)
            (void)HASSPECDEVD(ctx, fp, &sb);
#endif /* defined(HASSPECDEVD) */

            if (!(Fxover & XO_FILESYS)) {

                /*
                 * Unless "-x" or "-x f" was specified, don't cross over file
                 * system mount points.
                 */
                if (sb.st_dev != ddev)
                    continue;
            }
            if ((sb.st_mode & S_IFMT) == S_IFLNK) {

                /*
                 * If this is a symbolic link and "-x_ or "-x l" was specified,
                 * Statsafely() the entry and process it.
                 *
                 * Otherwise skip symbolic links.
                 */
                if (Fxover & XO_SYMLINK) {
                    if (statsafely(ctx, fp, &sb)) {
                        if ((en = errno) != ENOENT) {
                            if (!Fwarn) {
                                (void)fprintf(stderr,
                                              "%s: WARNING: can't stat(", Pn);
                                safestrprt(fp, stderr, 0);
                                (void)fprintf(stderr, ") symbolc link: %s\n",
                                              strerror(en));
                            }
                        }
                        continue;
                    }
                } else
                    continue;
            }
            if (av[0]) {
                (void)free((FREE_P *)av[0]);
                av[0] = (char *)NULL;
            }
            av[0] = mkstrcpy(fp, (MALLOC_S *)NULL);
            if ((sb.st_mode & S_IFMT) == S_IFDIR && descend)

                /*
                 * Stack a subdirectory according to the descend argument.
                 */
                stkdir(ctx, av[0]);
            /*
             * Use ck_file_arg() to record the entry for searching.  Force it
             * to consider the entry a file, not a file system.
             */
            if (!ck_file_arg(ctx, 0, 1, av, 1, 1, &sb, 0)) {
                av[0] = (char *)NULL;
                fct++;
            }
        }
        (void)CloseDir(dfp);
        if (dn && dn != d) {
            (void)free((FREE_P *)dn);
            dn = (char *)NULL;
        }
    }
    /*
     * Free malloc()'d space.
     */
    if (dn && dn != d) {
        (void)free((FREE_P *)dn);
        dn = (char *)NULL;
    }
    if (av[0] && av[0] != fp) {
        (void)free((FREE_P *)av[0]);
        av[0] = (char *)NULL;
    }
    if (fp) {
        (void)free((FREE_P *)fp);
        fp = (char *)NULL;
    }
    if (Dstk) {
        (void)free((FREE_P *)Dstk);
        Dstk = (char **)NULL;
    }
    if (!fct) {

        /*
         * Warn if no files were recorded for searching.
         */
        if (!Fwarn) {
            (void)fprintf(stderr,
                          "%s: WARNING: no files found in directory: ", Pn);
            safestrprt(d, stderr, 1);
        }
        return (1);
    }
    return (0);
}

/*
 * enter_id() - enter PGID or PID for searching
 */

int enter_id(struct lsof_context *ctx, /* context */
             enum IDType ty,           /* type: PGID or PID */
             char *p)                  /* process group ID string pointer */
{
    char *cp;
    int err, i, id, j, mx, n, ni, nx, x;
    struct int_lst *s;

    if (!p) {
        (void)fprintf(stderr, "%s: no process%s ID specified\n", Pn,
                      (ty == PGID) ? " group" : "");
        return (1);
    }
    /*
     * Convert and store the ID.
     */
    for (cp = p, err = 0; *cp;) {

        /*
         * Assemble ID.
         */
        for (i = id = x = 0; *cp && *cp != ','; cp++) {
            if (!i) {
                i = 1;
                if (*cp == '^') {
                    x = 1;
                    continue;
                }
            }

#if defined(__STDC__)
            if (!isdigit((unsigned char)*cp))
#else  /* !defined(__STDC__) */
            if (!isascii(*cp) || !isdigit((unsigned char)*cp))
#endif /* __STDC__ */

            {
                (void)fprintf(stderr, "%s: illegal process%s ID: ", Pn,
                              (ty == PGID) ? " group" : "");
                safestrprt(p, stderr, 1);
                return (1);
            }
            id = (id * 10) + *cp - '0';
        }
        if (*cp)
            cp++;
        if (ty == PGID) {
            if (lsof_select_pgid(ctx, id, x)) {
                err = 1;
            }
        } else {
            if (lsof_select_pid(ctx, id, x)) {
                err = 1;
            }
        }
    }
    return (err);
}

/*
 * enter_network_address() - enter Internet address for searching
 */

int enter_network_address(struct lsof_context *ctx, /* context */
                          char *na) /* Internet address string pointer */
{
    int ae, i, pr;
    int ep = -1;
    int ft = 0;
    struct hostent *he = (struct hostent *)NULL;
    char *hn = (char *)NULL;
    MALLOC_S l;
    struct nwad n;
    char *p, *wa;
    int pt = 0;
    int pu = 0;
    struct servent *se, *se1;
    char *sn = (char *)NULL;
    int sp = -1;
    MALLOC_S snl = 0;

#if defined(HASIPv6)
    char *cp;
#endif /* defined(HASIPv6) */

    if (!na) {
        (void)fprintf(stderr, "%s: no network address specified\n", Pn);
        return (1);
    }
    zeromem((char *)&n, sizeof(n));
    wa = na;
    /*
     * Process an IP version type specification, IPv4 or IPv6, optionally
     * followed by a '@' and a host name or Internet address, or a ':' and a
     * service name or port number.
     */
    if ((*wa == '4') || (*wa == '6')) {
        if (*wa == '4')
            ft = 4;
        else if (*wa == '6') {

#if defined(HASIPv6)
            ft = 6;
#else  /* !defined(HASIPv6) */
            (void)fprintf(stderr, "%s: IPv6 not supported: -i ", Pn);
            safestrprt(na, stderr, 1);
            goto nwad_exit;
#endif /* defined(HASIPv6) */
        }
        wa++;
        if (!*wa) {

            /*
             * If nothing follows 4 or 6, then all network files of the
             * specified IP version are selected.  Sequential -i, -i4, and
             * -i6 specifications interact logically -- e.g., -i[46] followed
             * by -i[64] is the same as -i.
             */
            if (!Fnet) {
                Fnet = 1;
                FnetTy = ft;
            } else {
                if (FnetTy) {
                    if (FnetTy != ft)
                        FnetTy = 0;
                } else
                    FnetTy = ft;
            }
            return (0);
        }
    } else if (Fnet)
        ft = FnetTy;
    /*
     * If an IP version has been specified, use it to set the address family.
     */
    switch (ft) {
    case 4:
        n.af = AF_INET;
        break;

#if defined(HASIPv6)
    case 6:
        n.af = AF_INET6;
        break;
#endif /* defined(HASIPv6) */
    }
    /*
     * Process protocol name, optionally followed by a '@' and a host name or
     * Internet address, or a ':' and a service name or port number.
     */
    if (*wa && *wa != '@' && *wa != ':') {
        for (p = wa; *wa && *wa != '@' && *wa != ':'; wa++)
            ;
        if ((l = wa - p)) {
            if (!(n.proto = mkstrcat(p, l, (char *)NULL, -1, (char *)NULL, -1,
                                     (MALLOC_S *)NULL))) {
                (void)fprintf(stderr,
                              "%s: no space for protocol name from: -i ", Pn);
                safestrprt(na, stderr, 1);
            nwad_exit:
                if (n.proto)
                    (void)free((FREE_P *)n.proto);
                if (hn)
                    (void)free((FREE_P *)hn);
                if (sn)
                    (void)free((FREE_P *)sn);
                return (1);
            }
            /*
             * The protocol name should be "tcp", "udp" or "udplite".
             */
            if ((strcasecmp(n.proto, "tcp") != 0) &&
                (strcasecmp(n.proto, "udp") != 0) &&
                (strcasecmp(n.proto, "udplite") != 0)) {
                (void)fprintf(stderr, "%s: unknown protocol name (%s) in: -i ",
                              Pn, n.proto);
                safestrprt(na, stderr, 1);
                goto nwad_exit;
            }
            /*
             * Convert protocol name to lower case.
             */
            for (p = n.proto; *p; p++) {
                if (*p >= 'A' && *p <= 'Z')
                    *p = *p - 'A' + 'a';
            }
        }
    }
    /*
     * Process an IPv4 address (1.2.3.4), IPv6 address ([1:2:3:4:5:6:7:8]),
     * or host name, preceded by a '@' and optionally followed by a colon
     * and a service name or port number.
     */
    if (*wa == '@') {
        wa++;
        if (!*wa || *wa == ':') {

#if defined(HASIPv6)
        unacc_address:
#endif /* defined(HASIPv6) */

            (void)fprintf(stderr, "%s: unacceptable Internet address in: -i ",
                          Pn);
            safestrprt(na, stderr, 1);
            goto nwad_exit;
        }

        if ((p = isIPv4addr(wa, n.a, sizeof(n.a)))) {

            /*
             * Process IPv4 address.
             */
            if (ft == 6) {
                (void)fprintf(stderr, "%s: IPv4 addresses are prohibited: -i ",
                              Pn);
                safestrprt(na, stderr, 1);
                goto nwad_exit;
            }
            wa = p;
            n.af = AF_INET;
        } else if (*wa == '[') {

#if defined(HASIPv6)
            /*
             * Make sure IPv6 addresses are permitted.  If they are, assemble
             * one.
             */
            if (ft == 4) {
                (void)fprintf(stderr, "%s: IPv6 addresses are prohibited: -i ",
                              Pn);
                safestrprt(na, stderr, 1);
                goto nwad_exit;
            }
            if (!(cp = strrchr(++wa, ']')))
                goto unacc_address;
            *cp = '\0';
            i = inet_pton(AF_INET6, wa, (void *)&n.a);
            *cp = ']';
            if (i != 1)
                goto unacc_address;
            for (ae = i = 0; i < MAX_AF_ADDR; i++) {
                if ((ae |= n.a[i]))
                    break;
            }
            if (!ae)
                goto unacc_address;
            if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)&n.a[0])) {
                if (ft == 6) {
                    (void)fprintf(stderr,
                                  "%s: IPv4 addresses are prohibited: -i ", Pn);
                    safestrprt(na, stderr, 1);
                    goto nwad_exit;
                }
                for (i = 0; i < 4; i++) {
                    n.a[i] = n.a[i + 12];
                }
                n.af = AF_INET;
            } else
                n.af = AF_INET6;
            wa = cp + 1;
#else  /* !defined(HASIPv6) */
            (void)fprintf(stderr, "%s: unsupported IPv6 address in: -i ", Pn);
            safestrprt(na, stderr, 1);
            goto nwad_exit;
#endif /* defined(HASIPv6) */

        } else {

            /*
             * Assemble host name.
             */
            for (p = wa; *p && *p != ':'; p++)
                ;
            if ((l = p - wa)) {
                if (!(hn = mkstrcat(wa, l, (char *)NULL, -1, (char *)NULL, -1,
                                    (MALLOC_S *)NULL))) {
                    (void)fprintf(stderr, "%s: no space for host name: -i ",
                                  Pn);
                    safestrprt(na, stderr, 1);
                    goto nwad_exit;
                }

#if defined(HASIPv6)

                /*
                 * If no IP version has been specified, look up an IPv6 host
                 * name first.  If that fails, look up an IPv4 host name.
                 *
                 * If the IPv6 version has been specified, look up the host
                 * name only under its IP version specification.
                 */
                if (!ft)
                    n.af = AF_INET6;
                if (!(he = lkup_hostnm(hn, &n)) && !ft) {
                    n.af = AF_INET;
                    he = lkup_hostnm(hn, &n);
                }
#else  /* !defined(HASIPv6) */
                if (!ft)
                    n.af = AF_INET;
                he = lkup_hostnm(hn, &n);
#endif /* defined(HASIPv6) */

                if (!he) {
                    fprintf(stderr, "%s: unknown host name (%s) in: -i ", Pn,
                            hn);
                    safestrprt(na, stderr, 1);
                    goto nwad_exit;
                }
            }
            wa = p;
        }
    }
    /*
     * If there is no port number, enter the address.
     */
    if (!*wa)
        goto nwad_enter;
    /*
     * Process a service name or port number list, preceded by a colon.
     *
     * Entries of the list are separated with commas; elements of a numeric
     * range are specified with a separating minus sign (`-'); all service names
     * must belong to the same protocol; embedded spaces are not allowed.  An
     * embedded minus sign in a name is taken to be part of the name, the
     * starting entry of a range can't be a service name.
     */
    if (*wa != ':' || *(wa + 1) == '\0') {

    unacc_port:
        (void)fprintf(stderr, "%s: unacceptable port specification in: -i ",
                      Pn);
        safestrprt(na, stderr, 1);
        goto nwad_exit;
    }
    for (++wa; wa && *wa; wa++) {
        for (ep = pr = sp = 0; *wa; wa++) {
            if (*wa < '0' || *wa > '9') {

                /*
                 * Convert service name to port number, using already-specified
                 * protocol name.  A '-' is taken to be part of the name; hence
                 * the starting entry of a range can't be a service name.
                 */
                for (p = wa; *wa && *wa != ','; wa++)
                    ;
                if (!(l = wa - p)) {
                    (void)fprintf(stderr, "%s: invalid service name: -i ", Pn);
                    safestrprt(na, stderr, 1);
                    goto nwad_exit;
                }
                if (sn) {
                    if (l > snl) {
                        sn = (char *)realloc((MALLOC_P *)sn, l + 1);
                        snl = l;
                    }
                } else {
                    sn = (char *)malloc(l + 1);
                    snl = l;
                }
                if (!sn) {
                    (void)fprintf(stderr, "%s: no space for service name: -i ",
                                  Pn);
                    safestrprt(na, stderr, 1);
                    goto nwad_exit;
                }
                (void)strncpy(sn, p, l);
                *(sn + l) = '\0';
                if (n.proto) {

                    /*
                     * If the protocol has been specified, look up the port
                     * number for the service name for the specified protocol.
                     */
                    if (!(se = getservbyname(sn, n.proto))) {
                        (void)fprintf(stderr,
                                      "%s: unknown service %s for %s in: -i ",
                                      Pn, sn, n.proto);
                        safestrprt(na, stderr, 1);
                        goto nwad_exit;
                    }
                    pt = (int)ntohs(se->s_port);
                } else {

                    /*
                     * If no protocol has been specified, look up the port
                     * numbers for the service name for both TCP and UDP.
                     */
                    if ((se = getservbyname(sn, "tcp")))
                        pt = (int)ntohs(se->s_port);
                    if ((se1 = getservbyname(sn, "udp")))
                        pu = (int)ntohs(se1->s_port);
                    if (!se && !se1) {
                        (void)fprintf(stderr, "%s: unknown service %s in: -i ",
                                      Pn, sn);
                        safestrprt(na, stderr, 1);
                        goto nwad_exit;
                    }
                    if (se && se1 && pt != pu) {
                        (void)fprintf(
                            stderr,
                            "%s: TCP=%d and UDP=%d %s ports conflict;\n", Pn,
                            pt, pu, sn);
                        (void)fprintf(
                            stderr,
                            "      specify \"tcp:%s\" or \"udp:%s\": -i ", sn,
                            sn);
                        safestrprt(na, stderr, 1);
                        goto nwad_exit;
                    }
                    if (!se && se1)
                        pt = pu;
                }
                if (pr)
                    ep = pt;
                else {
                    sp = pt;
                    if (*wa == '-')
                        pr++;
                }
            } else {

                /*
                 * Assemble port number.
                 */
                for (; *wa && *wa != ','; wa++) {
                    if (*wa == '-') {
                        if (pr)
                            goto unacc_port;
                        pr++;
                        break;
                    }
                    if (*wa < '0' || *wa > '9')
                        goto unacc_port;
                    if (pr)
                        ep = (ep * 10) + *wa - '0';
                    else
                        sp = (sp * 10) + *wa - '0';
                }
            }
            if (!*wa || *wa == ',')
                break;
            if (pr)
                continue;
            goto unacc_port;
        }
        if (!pr)
            ep = sp;
        if (ep < sp)
            goto unacc_port;
        /*
         * Enter completed port or port range specification.
         */

    nwad_enter:

        for (i = 1; i;) {
            if (enter_nwad(ctx, &n, sp, ep, na, he))
                goto nwad_exit;

#if defined(HASIPv6)
            /*
             * If IPv6 is enabled, a host name was specified, and the
             * associated * address is for the AF_INET6 address family,
             * try to get and address for the AF_INET family, too, unless
             * IPv4 is prohibited.
             */
            if (hn && (n.af == AF_INET6) && (ft != 6)) {
                n.af = AF_INET;
                if ((he = lkup_hostnm(hn, &n)))
                    continue;
            }
#endif /* defined(HASIPv6) */

            i = 0;
        }
        if (!*wa)
            break;
    }
    if (sn)
        (void)free((FREE_P *)sn);
    return (0);
}

/*
 * enter_nwad() - enter nwad structure
 */

static int enter_nwad(struct lsof_context *ctx, /* context */
                      struct nwad *n,     /* pointer to partially completed
                                           * nwad (less port) */
                      int sp,             /* starting port number */
                      int ep,             /* ending port number */
                      char *s,            /* string that states the address */
                      struct hostent *he) /* pointer to hostent struct from
                                           * which network address came */
{
    int ac;
    unsigned char *ap;
    static int na = 0;
    struct nwad nc;
    struct nwad *np;
    /*
     * Allocate space for the argument specification.
     */
    if (strlen(s)) {
        if (!(n->arg = mkstrcpy(s, (MALLOC_S *)NULL))) {
            (void)fprintf(stderr, "%s: no space for Internet argument: -i ",
                          Pn);
            safestrprt(s, stderr, 1);
            Error(ctx);
        }
    } else
        n->arg = (char *)NULL;
    /*
     * Loop through all hostent addresses.
     */
    for (ac = 1, nc = *n;;) {

        /*
         * Test address specification -- it must contain at least one of:
         * protocol, Internet address or port.  If correct, link into search
         * list.
         */
        if (!nc.proto && !nc.a[0] && !nc.a[1] && !nc.a[2] && !nc.a[3]

#if defined(HASIPv6)
            && (nc.af != AF_INET6 ||
                (!nc.a[4] && !nc.a[5] && !nc.a[6] && !nc.a[7] && !nc.a[8] &&
                 !nc.a[9] && !nc.a[10] && !nc.a[11] && !nc.a[12] && !nc.a[13] &&
                 !nc.a[14] && !nc.a[15]))
#endif /* defined(HASIPv6) */

            && sp == -1) {
            (void)fprintf(stderr,
                          "%s: incomplete Internet address specification: -i ",
                          Pn);
            safestrprt(s, stderr, 1);
            return (1);
        }
        /*
         * Limit the network address chain length to MAXNWAD for reasons of
         * search efficiency.
         */
        if (na >= MAXNWAD) {
            (void)fprintf(stderr,
                          "%s: network address limit (%d) exceeded: -i ", Pn,
                          MAXNWAD);
            safestrprt(s, stderr, 1);
            return (1);
        }
        /*
         * Allocate space for the address specification.
         */
        if ((np = (struct nwad *)malloc(sizeof(struct nwad))) == NULL) {
            (void)fprintf(stderr, "%s: no space for network address from: -i ",
                          Pn);
            safestrprt(s, stderr, 1);
            return (1);
        }
        /*
         * Construct and link the address specification.
         */
        *np = nc;
        np->sport = sp;
        np->eport = ep;
        np->f = 0;
        np->next = Nwad;
        Nwad = np;
        na++;
        /*
         * If the network address came from gethostbyname(), advance to
         * the next address; otherwise quit.
         */
        if (!he)
            break;
        if (!he->h_addr_list[ac -
                             1]) /* Check if address list ended prematurely */
            break;
        if (!(ap = (unsigned char *)he->h_addr_list[ac++]))
            break;

#if defined(HASIPv6)
        {
            int i;

            for (i = 0; (i < (he->h_length - 1)) && (i < (MAX_AF_ADDR - 1));
                 i++) {
                nc.a[i] = *ap++;
            }
            nc.a[i] = *ap;
        }
#else  /* !defined(HASIPv6) */
        nc.a[0] = *ap++;
        nc.a[1] = *ap++;
        nc.a[2] = *ap++;
        nc.a[3] = *ap;
#endif /* defined(HASIPv6) */
    }
    return (0);
}

#if defined(HASTCPUDPSTATE)
/*
 * enter_state_spec() -- enter TCP and UDP state specifications
 */

int enter_state_spec(struct lsof_context *ctx,
                     char *ss) /* state specification string */
{
    char *cp, *ne, *ns, *pr;
    int err, d, f, i, tx, x;
    static char *ssc = (char *)NULL;
    char *ty;
    /*
     * Check the protocol specification.
     */
    if (!strncasecmp(ss, "tcp:", 4)) {
        pr = "TCP";
        tx = 0;
    }

#    if !defined(USE_LIB_PRINT_TCPTPI)
    else if (!strncasecmp(ss, "UDP:", 4)) {
        pr = "UDP";
        tx = 1;
    }

#    endif /* !defined(USE_LIB_PRINT_TCPTPI) */

    else {
        (void)fprintf(stderr, "%s: unknown -s protocol: \"%s\"\n", Pn, ss);
        return (1);
    }
    cp = ss + 4;
    if (!*cp) {
        (void)fprintf(stderr, "%s: no %s state names in: %s\n", Pn, pr, ss);
        return (1);
    }
    (void)build_IPstates(ctx);
    if (!(tx ? UdpSt : TcpSt)) {
        (void)fprintf(stderr, "%s: no %s state names available: %s\n", Pn, pr,
                      ss);
        return (1);
    }
    /*
     * Allocate the inclusion and exclusion tables for the protocol.
     */
    if (tx) {
        if (UdpNstates) {
            if (!UdpStI) {
                if (!(UdpStI = (unsigned char *)calloc(
                          (MALLOC_S)UdpNstates, sizeof(unsigned char)))) {
                    ty = "UDP state inclusion";

                no_IorX_space:

                    (void)fprintf(stderr, "%s: no %s table space\n", Pn, ty);
                    Error(ctx);
                }
            }
            if (!UdpStX) {
                if (!(UdpStX = (unsigned char *)calloc(
                          (MALLOC_S)UdpNstates, sizeof(unsigned char)))) {
                    ty = "UDP state exclusion";
                    goto no_IorX_space;
                }
            }
        }
    } else {
        if (TcpNstates) {
            if (!TcpStI) {
                if (!(TcpStI = (unsigned char *)calloc(
                          (MALLOC_S)TcpNstates, sizeof(unsigned char)))) {
                    ty = "TCP state inclusion";
                    goto no_IorX_space;
                }
            }
            if (!TcpStX) {
                if (!(TcpStX = (unsigned char *)calloc(
                          (MALLOC_S)TcpNstates, sizeof(unsigned char)))) {
                    ty = "TCP state exclusion";
                    goto no_IorX_space;
                }
            }
        }
    }
    /*
     * Convert the state names in the rest of the string to state indexes and
     * record them in the appropriate inclusion or exclusion table.
     */
    if (ssc)
        (void)free((MALLOC_P *)ssc);
    if (!(ssc = mkstrcpy(cp, (MALLOC_S *)NULL))) {
        (void)fprintf(stderr, "%s: no temporary state argument space for: %s\n",
                      Pn, ss);
        Error(ctx);
    }
    cp = ssc;
    err = 0;
    while (*cp) {

        /*
         * Determine inclusion or exclusion for this state name.
         */
        if (*cp == '^') {
            x = 1;
            cp++;
        } else
            x = 0;
        /*
         * Find the end of the state name.  Make sure it is non-null in length
         * and terminated with '\0'.
         */
        ns = cp;
        while (*cp && (*cp != ',')) {
            cp++;
        }
        ne = cp;
        if (*cp) {
            *cp = '\0';
            cp++;
        }
        if (!(size_t)(ne - ns)) {
            (void)fprintf(stderr, "%s: NULL %s state name in: %s\n", Pn, pr,
                          ss);
            err = 1;
            continue;
        }
        /*
         * Find the state name in the appropriate table.
         */
        f = 0;
        if (tx) {
            if (UdpSt) {
                for (i = 0; i < UdpNstates; i++) {
                    if (!strcasecmp(ns, UdpSt[i])) {
                        f = 1;
                        break;
                    }
                }
            }
        } else {
            if (TcpSt) {
                for (i = 0; i < TcpNstates; i++) {
                    if (!strcasecmp(ns, TcpSt[i])) {
                        f = 1;
                        break;
                    }
                }
            }
        }
        if (!f) {
            (void)fprintf(stderr, "%s: unknown %s state name: %s\n", Pn, pr,
                          ns);
            err = 1;
            continue;
        }
        /*
         * Set the inclusion or exclusion status in the appropriate table.
         */
        d = 0;
        if (x) {
            if (tx) {
                if (!UdpStX[i]) {
                    UdpStX[i] = 1;
                    UdpStXn++;
                } else
                    d = 1;
            } else {
                if (!TcpStX[i]) {
                    TcpStX[i] = 1;
                    TcpStXn++;
                } else
                    d = 1;
            }
        } else {
            if (tx) {
                if (!UdpStI[i]) {
                    UdpStI[i] = 1;
                    UdpStIn++;
                } else
                    d = 1;
            } else {
                if (!TcpStI[i]) {
                    TcpStI[i] = 1;
                    TcpStIn++;
                } else
                    d = 1;
            }
        }
        if (d) {

            /*
             * Report a duplicate.
             */
            (void)fprintf(stderr, "%s: duplicate %s %sclusion: %s\n", Pn, pr,
                          x ? "ex" : "in", ns);
            err = 1;
        }
    }
    /*
     * Release any temporary space and return.
     */
    if (ssc) {
        (void)free((MALLOC_P *)ssc);
        ssc = (char *)NULL;
    }
    return (err);
}
#endif /* defined(HASTCPUDPSTATE) */

/*
 * enter_cmd() - enter -c option
 */

int enter_cmd(struct lsof_context *ctx, /* context */
              char *opt,                /* option name */
              char *s)                  /* string to enter */
{
    char *cp;
    short x;
    MALLOC_S len;
    struct str_lst *lpt;

    if (!s || *s == '-' || *s == '+') {
        (void)fprintf(stderr, "%s: missing %s option value\n", Pn, opt);
        return (1);
    }
    if (*s == '^') {
        x = 1;
        s++;
    } else {
        x = 0;
    }
    if (lsof_select_process(ctx, s, x) != LSOF_SUCCESS) {
        return 1;
    }
    return 0;
}

/*
 * enter_uid() - enter User Identifier for searching
 */

int enter_uid(struct lsof_context *ctx, /* context */
              char *us)                 /* User IDentifier string pointer */
{
    int err, i, j, lnml, nn;
    unsigned char excl;
    MALLOC_S len;
    char lnm[LOGINML + 1], *lp;
    struct passwd *pw;
    char *s, *st;
    uid_t uid;

    if (!us) {
        (void)fprintf(stderr, "%s: no UIDs specified\n", Pn);
        return (1);
    }
    for (err = 0, s = us; *s;) {

        /*
         * Assemble next User IDentifier.
         */
        for (excl = i = j = lnml = nn = uid = 0, st = s; *s && *s != ',';
             i++, s++) {
            if (lnml >= LOGINML) {
                while (*s && *s != ',') {
                    s++;
                    lnml++;
                }
                (void)fprintf(stderr, "%s: -u login name > %d characters: ", Pn,
                              (int)LOGINML);
                safestrprtn(st, lnml, stderr, 1);
                err = j = 1;
                break;
            }
            if (i == 0 && *s == '^') {
                excl = 1;
                continue;
            }
            lnm[lnml++] = *s;
            if (nn)
                continue;

#if defined(__STDC__)
            if (isdigit((unsigned char)*s))
#else  /* !defined(__STDC__) */
            if (isascii(*s) && isdigit((unsigned char)*s))
#endif /* defined(__STDC__) */

                uid = (uid * 10) + *s - '0';
            else
                nn++;
        }
        if (*s)
            s++;
        if (j)
            continue;
        if (nn) {
            lnm[lnml++] = '\0';
            if ((pw = getpwnam(lnm)) == NULL) {
                (void)fprintf(stderr, "%s: can't get UID for ", Pn);
                safestrprt(lnm, stderr, 1);
                err = 1;
                continue;
            } else
                uid = pw->pw_uid;
        }

#if defined(HASSECURITY) && !defined(HASNOSOCKSECURITY)
        /*
         * If the security mode is enabled, only the root user may list files
         * belonging to user IDs other than the real user ID of this lsof
         * process.  If HASNOSOCKSECURITY is also defined, then anyone may
         * list anyone else's socket files.
         */
        if (Myuid && uid != Myuid) {
            (void)fprintf(
                stderr,
                "%s: ID %d request rejected because of security mode.\n", Pn,
                uid);
            err = 1;
            continue;
        }
#endif /* defined(HASSECURITY)  && !defined(HASNOSOCKSECURITY) */

        if (nn) {
            if (lsof_select_login(ctx, lnm, excl)) {
                Error(ctx);
                return (1);
            }
        } else {
            if (lsof_select_uid(ctx, uid, excl)) {
                Error(ctx);
                return (1);
            }
        }
    }
    return (err);
}

/*
 * isIPv4addr() - is host name an IPv4 address
 */

static char *isIPv4addr(char *hn,         /* host name */
                        unsigned char *a, /* address receptor */
                        int al)           /* address receptor length */
{
    int dc = 0;          /* dot count */
    int i;               /* temporary index */
    int ov[MIN_AF_ADDR]; /* octet values */
    int ovx = 0;         /* ov[] index */
                         /*
                          * The host name must begin with a number and the return octet value
                          * arguments must be acceptable.
                          */
    if ((*hn < '0') || (*hn > '9'))
        return ((char *)NULL);
    if (!a || (al < MIN_AF_ADDR))
        return ((char *)NULL);
    /*
     * Start the first octet assembly, then parse tge remainder of the host
     * name for four octets, separated by dots.
     */
    ov[0] = (int)(*hn++ - '0');
    while (*hn && (*hn != ':')) {
        if (*hn == '.') {

            /*
             * Count a dot.  Make sure a preceding octet value has been
             * assembled.  Don't assemble more than MIN_AF_ADDR octets.
             */
            dc++;
            if ((ov[ovx] < 0) || (ov[ovx] > 255))
                return ((char *)NULL);
            if (++ovx > (MIN_AF_ADDR - 1))
                return ((char *)NULL);
            ov[ovx] = -1;
        } else if ((*hn >= '0') && (*hn <= '9')) {

            /*
             * Assemble an octet.
             */
            if (ov[ovx] < 0)
                ov[ovx] = (int)(*hn - '0');
            else
                ov[ovx] = (ov[ovx] * 10) + (int)(*hn - '0');
        } else {

            /*
             * A non-address character has been detected.
             */
            return ((char *)NULL);
        }
        hn++;
    }
    /*
     * Make sure there were three dots and four non-null octets.
     */
    if ((dc != 3) || (ovx != (MIN_AF_ADDR - 1)) || (ov[ovx] < 0) ||
        (ov[ovx] > 255))
        return ((char *)NULL);
    /*
     * Copy the octets as unsigned characters and return the ending host name
     * character position.
     */
    for (i = 0; i < MIN_AF_ADDR; i++) {
        a[i] = (unsigned char)ov[i];
    }
    return (hn);
}

/*
 * lkup_hostnm() - look up host name
 */

static struct hostent *
lkup_hostnm(char *hn,       /* host name */
            struct nwad *n) /* network address destination */
{
    unsigned char *ap;
    struct hostent *he;
    int ln;
    /*
     * Get hostname structure pointer.  Return NULL if there is none.
     */

#if defined(HASIPv6)
    he = gethostbyname2(hn, n->af);
#else  /* !defined(HASIPv6) */
    he = gethostbyname(hn);
#endif /* defined(HASIPv6) */

    if (!he || !he->h_addr)
        return (he);
        /*
         * Copy first hostname structure address to destination structure.
         */

#if defined(HASIPv6)
    if (n->af != he->h_addrtype)
        return ((struct hostent *)NULL);
    if (n->af == AF_INET6) {

        /*
         * Copy an AF_INET6 address.
         */
        if (he->h_length > MAX_AF_ADDR)
            return ((struct hostent *)NULL);
        (void)memcpy((void *)&n->a[0], (void *)he->h_addr, he->h_length);
        if ((ln = MAX_AF_ADDR - he->h_length) > 0)
            zeromem((char *)&n->a[he->h_length], ln);
        return (he);
    }
#endif /* defined(HASIPv6) */

    /*
     * Copy an AF_INET address.
     */
    if (he->h_length != 4)
        return ((struct hostent *)NULL);
    ap = (unsigned char *)he->h_addr;
    n->a[0] = *ap++;
    n->a[1] = *ap++;
    n->a[2] = *ap++;
    n->a[3] = *ap;
    if ((ln = MAX_AF_ADDR - 4) > 0)
        zeromem((char *)&n->a[4], ln);
    return (he);
}