lib/misc.c - master - githubmirror/lsof

lib/misc.c
1 656 строк47 KB
Jiajie Chen
Fix memory leaks and add resource cleanup in lsof_destroy
31 мар 2026, 15:19
31 мар 2026, 15:194cdff50
/*
 * misc.c - common miscellaneous 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 "dlsof.h"

#if defined(HASWIDECHAR)
#    if defined(WIDECHARINCL)
#        include WIDECHARINCL
#    endif /* defined(WIDECHARINCL) */
#    if defined(HASWCTYPE_H)
#        include <wctype.h>
#    endif /* defined(HASWCTYPE_H) */
#endif     /* defined(HASWIDECHAR) */

/*
 * Local definitions
 */

#if !defined(MAXSYMLINKS)
#    define MAXSYMLINKS 32
#endif /* !defined(MAXSYMLINKS) */

/*
 * Local function prototypes
 */

static void closePipes(struct lsof_context *ctx);
static int dolstat(char *path, char *buf, int len);
static int dostat(char *path, char *buf, int len);
static int doreadlink(char *path, char *buf, int len);
static int doinchild(struct lsof_context *ctx,
                     int (*fn)(char *path, char *buf, int len), char *fp,
                     char *rbuf, int rbln);

#if defined(HASINTSIGNAL)
static int handleint(int sig);
#else  /* !defined(HASINTSIGNAL) */
static void handleint(int sig);
#endif /* defined(HASINTSIGNAL) */

/*
 * Local variables
 */

static jmp_buf Jmp_buf; /* jump buffer for child process signals */
static int CtSigs[] = {0, SIGINT, SIGKILL};
/* child termination signals (in order
 * of application) -- the first is a
 * dummy to allow pipe closure to
 * cause the child to exit */
#define NCTSIGS (sizeof(CtSigs) / sizeof(int))

#if defined(HASNLIST)
/*
 * build-Nl() - build kernel name list table
 */

void build_Nl(struct lsof_context *ctx,
              struct drive_Nl *d) /* data to drive the construction */
{
    struct drive_Nl *dp;
    int i, n;

    for (dp = d, n = 0; dp->nn; dp++, n++)
        ;
    if (n < 1) {
        (void)fprintf(stderr, "%s: can't calculate kernel name list length\n",
                      Pn);
        Error(ctx);
    }
    if (!(Nl = (struct NLIST_TYPE *)calloc((n + 1),
                                           sizeof(struct NLIST_TYPE)))) {
        (void)fprintf(
            stderr,
            "%s: can't allocate %d bytes to kernel name list structure\n", Pn,
            (int)((n + 1) * sizeof(struct NLIST_TYPE)));
        Error(ctx);
    }
    for (dp = d, i = 0; i < n; dp++, i++) {
        Nl[i].NL_NAME = dp->knm;
    }
    Nll = (int)((n + 1) * sizeof(struct NLIST_TYPE));
    Build_Nl = d;
}
#endif /* defined(HASNLIST) */

/*
 * childx() - make child process exit (if possible)
 */

void childx(struct lsof_context *ctx) {
    static int at, sx;
    pid_t wpid;

    if (Cpid > 1) {

        /*
         * First close the pipes to and from the child.  That should cause the
         * child to exit.  Compute alarm time shares.
         */
        (void)closePipes(ctx);
        if ((at = TmLimit / NCTSIGS) < TMLIMMIN)
            at = TMLIMMIN;
        /*
         * Loop, waiting for the child to exit.  After the first pass, help
         * the child exit by sending it signals.
         */
        for (sx = 0; sx < NCTSIGS; sx++) {
            if (setjmp(Jmp_buf)) {

                /*
                 * An alarm has rung.  Disable further alarms.
                 *
                 * If there are more signals to send, continue the signal loop.
                 *
                 * If the last signal has been sent, issue a warning (unless
                 * warninge have been suppressed) and exit the signal loop.
                 */
                (void)alarm(0);
                (void)signal(SIGALRM, SIG_DFL);
                if (sx < (NCTSIGS - 1))
                    continue;
                if (!Fwarn)
                    (void)fprintf(
                        stderr,
                        "%s: WARNING -- child process %d may be hung.\n", Pn,
                        (int)Cpid);
                break;
            }
            /*
             * Send the next signal to the child process, after the first pass
             * through the loop.
             *
             * Wrap the wait() with an alarm.
             */
            if (sx)
                (void)kill(Cpid, CtSigs[sx]);
            (void)signal(SIGALRM, handleint);
            (void)alarm(at);
            wpid = (pid_t)wait(NULL);
            (void)alarm(0);
            (void)signal(SIGALRM, SIG_DFL);
            if (wpid == Cpid)
                break;
        }
        Cpid = 0;
    }
}

/*
 * closePipes() - close open pipe file descriptors
 */

static void closePipes(struct lsof_context *ctx) {
    int i;

    for (i = 0; i < 4; i++) {
        if (Pipes[i] >= 0) {
            (void)close(Pipes[i]);
            Pipes[i] = -1;
        }
    }
}

/*
 * compdev() - compare Devtp[] entries
 */

int compdev(COMP_P *a1, COMP_P *a2) {
    struct l_dev **p1 = (struct l_dev **)a1;
    struct l_dev **p2 = (struct l_dev **)a2;

    if ((dev_t)((*p1)->rdev) < (dev_t)((*p2)->rdev))
        return (-1);
    if ((dev_t)((*p1)->rdev) > (dev_t)((*p2)->rdev))
        return (1);
    if ((INODETYPE)((*p1)->inode) < (INODETYPE)((*p2)->inode))
        return (-1);
    if ((INODETYPE)((*p1)->inode) > (INODETYPE)((*p2)->inode))
        return (1);
    return (strcmp((*p1)->name, (*p2)->name));
}

/*
 * closefrom_shim() -- provide closefrom() when unavailable
 */
void closefrom_shim(struct lsof_context *ctx, int low) {
    int i;
#if defined(HAS_CLOSEFROM)
    (void)closefrom(low);
#else /* !defined(HAS_CLOSEFROM) */
    /* fallback to SYS_close_range */
#    if defined(SYS_close_range)
    if (MaxFd > low && syscall(SYS_close_range, low, MaxFd - 1, 0) == 0)
        return;
#    endif
#    if defined(LINUX_LSOF_H)
    /* optimized fallback for Linux:
     * iterate /proc/self/fd and close fd's that are not that directory itself
     */
    long fd;
    char *endp;
    struct dirent *dent;
    DIR *dirp;

    dirp = opendir("/proc/self/fd");
    if (dirp) {
        while ((dent = readdir(dirp)) != NULL) {
            fd = strtol(dent->d_name, &endp, 10);
            if (dent->d_name != endp && *endp == '\0' && fd >= 0 &&
                fd < INT_MAX && fd >= low && fd != dirfd(dirp))
                (void)close((int)fd);
        }
        (void)closedir(dirp);
        return;
    }
#    endif
    /* slow brute force fallback */
    for (i = low; i < MaxFd; i++)
        (void)close(i);
#endif /* !defined(HAS_CLOSEFROM) */
}

/*
 * doinchild() -- do a function in a child process
 */

static int doinchild(struct lsof_context *ctx,
                     int (*fn)(char *path, char *buf,
                               int len), /* function to perform */
                     char *fp,           /* function parameter */
                     char *rbuf,         /* response buffer */
                     int rbln)           /* response buffer length */
{
    int en, rv;

    /*
     * Check reply buffer size.
     */
    if (!Fovhd && rbln > MAXPATHLEN) {
        (void)fprintf(stderr,
                      "%s: doinchild error; response buffer too large: %d\n",
                      Pn, rbln);
        Error(ctx);
    }
    /*
     * Set up to handle an alarm signal; handle an alarm signal; build
     * pipes for exchanging information with a child process; start the
     * child process; and perform functions in the child process.
     */
    if (!Fovhd) {
        if (setjmp(Jmp_buf)) {

            /*
             * Process an alarm that has rung.
             */
            (void)alarm(0);
            (void)signal(SIGALRM, SIG_DFL);
            (void)childx(ctx);
            errno = ETIMEDOUT;
            return (1);
        } else if (!Cpid) {

            /*
             * Create pipes to exchange function information with a child
             * process.
             */
            if (pipe(Pipes) < 0 || pipe(&Pipes[2]) < 0) {
                (void)fprintf(stderr, "%s: can't open pipes: %s\n", Pn,
                              strerror(errno));
                Error(ctx);
            }
            /*
             * Fork a child to execute functions.
             */
            if ((Cpid = fork()) == 0) {

                /*
                 * Begin the child process.
                 */

                int r_al, r_rbln;
                char r_arg[MAXPATHLEN + 1];
                union {
                    char r_rbuf[MAXPATHLEN + 1];
                    /*
                     * This field is only for adjusting the alignment of r_rbuf
                     * that can be used as an argument for stat().
                     */
                    struct stat _;
                } r;
                int (*r_fn)(char *path, char *buf, int len);
                /*
                 * Close sufficient open file descriptors except Pipes[0] and
                 * Pipes[3].
                 */

#if defined(HAS_DUP2)
                int rc;

                rc = dup2(Pipes[0], 0);
                if (rc < 0) {
                    (void)fprintf(stderr,
                                  "%s: can't dup Pipes[0] to fd 0: %s\n", Pn,
                                  strerror(errno));
                    Error(ctx);
                }
                Pipes[0] = 0;
                rc = dup2(Pipes[3], 1);
                if (rc < 0) {
                    (void)fprintf(stderr,
                                  "%s: can't dup Pipes.[3] to fd 1: %s\n", Pn,
                                  strerror(errno));
                    Error(ctx);
                }
                Pipes[3] = 1;
                (void)closefrom_shim(ctx, 2);
                Pipes[1] = -1;
                Pipes[2] = -1;

#else  /* !defined(HAS_DUP2) */
                int fd;

                for (fd = 0; fd < MaxFd; fd++) {
                    if (fd == Pipes[0] || fd == Pipes[3])
                        continue;
                    (void)close(fd);
                    if (fd == Pipes[1])
                        Pipes[1] = -1;
                    else if (fd == Pipes[2])
                        Pipes[2] = -1;
                }
                if (Pipes[1] >= 0) {
                    (void)close(Pipes[1]);
                    Pipes[1] = -1;
                }
                if (Pipes[2] >= 0) {
                    (void)close(Pipes[2]);
                    Pipes[2] = -1;
                }
#endif /* defined(HAS_DUP2) */

                /*
                 * Read function requests, process them, and return replies.
                 */
                for (;;) {
                    if (read(Pipes[0], (char *)&r_fn, sizeof(r_fn)) !=
                            (int)sizeof(r_fn) ||
                        read(Pipes[0], (char *)&r_al, sizeof(int)) !=
                            (int)sizeof(int) ||
                        r_al < 1 || r_al > (int)sizeof(r_arg) ||
                        read(Pipes[0], r_arg, r_al) != r_al ||
                        read(Pipes[0], (char *)&r_rbln, sizeof(r_rbln)) !=
                            (int)sizeof(r_rbln) ||
                        r_rbln < 1 || r_rbln > (int)sizeof(r.r_rbuf))
                        break;
                    zeromem(r.r_rbuf, r_rbln);
                    rv = r_fn(r_arg, r.r_rbuf, r_rbln);
                    en = errno;
                    if (write(Pipes[3], (char *)&rv, sizeof(rv)) !=
                            sizeof(rv) ||
                        write(Pipes[3], (char *)&en, sizeof(en)) !=
                            sizeof(en) ||
                        write(Pipes[3], r.r_rbuf, r_rbln) != r_rbln)
                        break;
                }
                (void)_exit(0);
            }
            /*
             * Continue in the parent process to finish the setup.
             */
            if (Cpid < 0) {
                (void)fprintf(stderr, "%s: can't fork: %s\n", Pn,
                              strerror(errno));
                Error(ctx);
            }
            (void)close(Pipes[0]);
            (void)close(Pipes[3]);
            Pipes[0] = Pipes[3] = -1;
        }
    }
    if (!Fovhd) {
        int len;

        /*
         * Send a function to the child and wait for the response.
         */
        len = strlen(fp) + 1;
        (void)signal(SIGALRM, handleint);
        (void)alarm(TmLimit);
        if (write(Pipes[1], (char *)&fn, sizeof(fn)) != sizeof(fn) ||
            write(Pipes[1], (char *)&len, sizeof(len)) != sizeof(len) ||
            write(Pipes[1], fp, len) != len ||
            write(Pipes[1], (char *)&rbln, sizeof(rbln)) != sizeof(rbln) ||
            read(Pipes[2], (char *)&rv, sizeof(rv)) != sizeof(rv) ||
            read(Pipes[2], (char *)&en, sizeof(en)) != sizeof(en) ||
            read(Pipes[2], rbuf, rbln) != rbln) {
            (void)alarm(0);
            (void)signal(SIGALRM, SIG_DFL);
            (void)childx(ctx);
            errno = ECHILD;
            return (-1);
        }
    } else {

        /*
         * Do the operation directly -- not in a child.
         */
        (void)signal(SIGALRM, handleint);
        (void)alarm(TmLimit);
        rv = fn(fp, rbuf, rbln);
        en = errno;
    }
    /*
     * Function completed, response collected -- complete the operation.
     */
    (void)alarm(0);
    (void)signal(SIGALRM, SIG_DFL);
    errno = en;
    return (rv);
}

/*
 * dolstat() - do an lstat() function
 */

static int dolstat(char *path, /* path */
                   char *rbuf, /* response buffer */
                   int rbln)   /* response buffer length */

/* ARGSUSED */

{
    return (lstat(path, (struct stat *)rbuf));
}

/*
 * doreadlink() -- do a readlink() function
 */

static int doreadlink(char *path, /* path */
                      char *rbuf, /* response buffer */
                      int rbln)   /* response buffer length */
{
    return (readlink(path, rbuf, rbln));
}

/*
 * dostat() - do a stat() function
 */

static int dostat(char *path, /* path */
                  char *rbuf, /* response buffer */
                  int rbln)   /* response buffer length */

/* ARGSUSED */

{
    return (stat(path, (struct stat *)rbuf));
}

#if defined(WILLDROPGID)
/*
 * dropgid() - drop setgid permission
 */

void dropgid(struct lsof_context *ctx) {
    if (!Setuidroot && Setgid) {
        if (setgid(Mygid) < 0) {
            (void)fprintf(stderr, "%s: can't setgid(%d): %s\n", Pn, (int)Mygid,
                          strerror(errno));
            Error(ctx);
        }
        Setgid = 0;
    }
}
#endif /* defined(WILLDROPGID) */

/*
 * enter_dev_ch() - enter device characters in file structure
 */

void enter_dev_ch(struct lsof_context *ctx, char *m) {
    char *mp;

    if (!m || *m == '\0')
        return;
    if (!(mp = mkstrcpy(m, (MALLOC_S *)NULL))) {
        (void)fprintf(stderr, "%s: no more dev_ch space at PID %d: \n", Pn,
                      Lp->pid);
        safestrprt(m, stderr, 1);
        Error(ctx);
    }
    if (Lf->dev_ch)
        (void)free((FREE_P *)Lf->dev_ch);
    Lf->dev_ch = mp;
}

/*
 * enter_IPstate() -- enter a TCP or UDP state
 */

void enter_IPstate(struct lsof_context *ctx, char *ty, /* type -- TCP or UDP */
                   char *nm, /* state name (may be NULL) */
                   int nr)   /* state number */
{

#if defined(USE_LIB_PRINT_TCPTPI)
    TcpNstates = nr;
#else  /* !defined(USE_LIB_PRINT_TCPTPI) */

    int al, i, j, oc, nn, ns, off, tx;
    char *cp;
    MALLOC_S len;
    /*
     * Check the type name and set the type index.
     */
    if (!ty) {
        (void)fprintf(stderr, "%s: no type specified to enter_IPstate()\n", Pn);
        Error(ctx);
    }
    if (!strcmp(ty, "TCP"))
        tx = 0;
    else if (!strcmp(ty, "UDP"))
        tx = 1;
    else {
        (void)fprintf(stderr, "%s: unknown type for enter_IPstate: %s\n", Pn,
                      ty);
        Error(ctx);
    }
    /*
     * If the name argument is NULL, reduce the allocated table to its minimum
     * size.
     */
    if (!nm) {
        if (tx) {
            if (UdpSt) {
                if (!UdpNstates) {
                    (void)free((MALLOC_P *)UdpSt);
                    UdpSt = (char **)NULL;
                }
                if (UdpNstates < UdpStAlloc) {
                    len = (MALLOC_S)(UdpNstates * sizeof(char *));
                    if (!(UdpSt = (char **)realloc((MALLOC_P *)UdpSt, len))) {
                        (void)fprintf(stderr, "%s: can't reduce UdpSt[]\n", Pn);
                        Error(ctx);
                    }
                }
                UdpStAlloc = UdpNstates;
            }
        } else {
            if (TcpSt) {
                if (!TcpNstates) {
                    (void)free((MALLOC_P *)TcpSt);
                    TcpSt = (char **)NULL;
                }
                if (TcpNstates < TcpStAlloc) {
                    len = (MALLOC_S)(TcpNstates * sizeof(char *));
                    if (!(TcpSt = (char **)realloc((MALLOC_P *)TcpSt, len))) {
                        (void)fprintf(stderr, "%s: can't reduce TcpSt[]\n", Pn);
                        Error(ctx);
                    }
                }
                TcpStAlloc = TcpNstates;
            }
        }
        return;
    }
    /*
     * Check the name and number.
     */
    if (strlen(nm) < 1) {
        (void)fprintf(stderr, "%s: bad %s name (\"%s\"), number=%d\n", Pn, ty,
                      nm, nr);
        Error(ctx);
    }
    /*
     * Make a copy of the name.
     */
    if (!(cp = mkstrcpy(nm, (MALLOC_S *)NULL))) {
        (void)fprintf(stderr, "%s: enter_IPstate(): no %s space for %s\n", Pn,
                      ty, nm);
        Error(ctx);
    }
    /*
     * Set the necessary offset for using nr as an index.  If it is
     * a new offset, adjust previous entries.
     */
    if ((nr < 0) && ((off = -nr) > (tx ? UdpStOff : TcpStOff))) {
        if (tx ? UdpSt : TcpSt) {

            /*
             * A new, larger offset (smaller negative state number) could mean
             * a previously allocated state table must be enlarged and its
             * previous entries moved.
             */
            oc = off - (tx ? UdpStOff : TcpStOff);
            al = tx ? UdpStAlloc : TcpStAlloc;
            ns = tx ? UdpNstates : TcpNstates;
            if ((nn = ns + oc) >= al) {
                while ((nn + 5) > al) {
                    al += TCPUDPALLOC;
                }
                len = (MALLOC_S)(al * sizeof(char *));
                if (tx) {
                    if (!(UdpSt = (char **)realloc((MALLOC_P *)UdpSt, len)))
                        goto no_IP_space;
                    UdpStAlloc = al;
                } else {
                    if (!(TcpSt = (char **)realloc((MALLOC_P *)TcpSt, len)))
                        goto no_IP_space;
                    TcpStAlloc = al;
                }
                for (i = 0, j = oc; i < oc; i++, j++) {
                    if (tx) {
                        if (i < UdpNstates)
                            UdpSt[j] = UdpSt[i];
                        UdpSt[i] = (char *)NULL;
                    } else {
                        if (i < TcpNstates)
                            TcpSt[j] = TcpSt[i];
                        TcpSt[i] = (char *)NULL;
                    }
                }
                if (tx)
                    UdpNstates += oc;
                else
                    TcpNstates += oc;
            }
        }
        if (tx)
            UdpStOff = off;
        else
            TcpStOff = off;
    }
    /*
     * Enter name as {Tc|Ud}pSt[nr + {Tc|Ud}pStOff].
     *
     * Allocate space, as required.
     */
    al = tx ? UdpStAlloc : TcpStAlloc;
    off = tx ? UdpStOff : TcpStOff;
    nn = nr + off + 1;
    if (nn > al) {
        i = tx ? UdpNstates : TcpNstates;
        while ((nn + 5) > al) {
            al += TCPUDPALLOC;
        }
        len = (MALLOC_S)(al * sizeof(char *));
        if (tx) {
            if (UdpSt)
                UdpSt = (char **)realloc((MALLOC_P *)UdpSt, len);
            else
                UdpSt = (char **)malloc(len);
            if (!UdpSt) {

            no_IP_space:

                (void)fprintf(stderr, "%s: no %s state space\n", Pn, ty);
                Error(ctx);
            }
            UdpNstates = nn;
            UdpStAlloc = al;
        } else {
            if (TcpSt)
                TcpSt = (char **)realloc((MALLOC_P *)TcpSt, len);
            else
                TcpSt = (char **)malloc(len);
            if (!TcpSt)
                goto no_IP_space;
            TcpNstates = nn;
            TcpStAlloc = al;
        }
        while (i < al) {
            if (tx)
                UdpSt[i] = (char *)NULL;
            else
                TcpSt[i] = (char *)NULL;
            i++;
        }
    } else {
        if (tx) {
            if (nn > UdpNstates)
                UdpNstates = nn;
        } else {
            if (nn > TcpNstates)
                TcpNstates = nn;
        }
    }
    if (tx) {
        if (UdpSt[nr + UdpStOff]) {

        dup_IP_state:

            (void)fprintf(
                stderr, "%s: duplicate %s state %d (already %s): %s\n", Pn, ty,
                nr, tx ? UdpSt[nr + UdpStOff] : TcpSt[nr + TcpStOff], nm);
            Error(ctx);
        }
        UdpSt[nr + UdpStOff] = cp;
    } else {
        if (TcpSt[nr + TcpStOff])
            goto dup_IP_state;
        TcpSt[nr + TcpStOff] = cp;
    }
#endif /* defined(USE_LIB_PRINT_TCPTPI) */
}

/*
 * enter_nm() - enter name in local file structure
 */

void enter_nm(struct lsof_context *ctx, char *m) {
    char *mp;

    if (!m || *m == '\0')
        return;
    if (!(mp = mkstrcpy(m, (MALLOC_S *)NULL))) {
        (void)fprintf(stderr, "%s: no more nm space at PID %d for: ", Pn,
                      Lp->pid);
        safestrprt(m, stderr, 1);
        Error(ctx);
    }
    if (Lf->nm)
        (void)free((FREE_P *)Lf->nm);
    Lf->nm = mp;
}

/*
 * Exit() - do a clean exit()
 */

void Exit(struct lsof_context *ctx, enum ExitStatus xv) /* exit() value */
{
    (void)childx(ctx);

#if defined(HASDCACHE)
    if (DCrebuilt && !Fwarn)
        (void)fprintf(stderr, "%s: WARNING: %s was updated.\n", Pn,
                      DCpath[DCpathX]);
#endif /* defined(HASDCACHE) */

    lsof_destroy(ctx);
    exit(xv);
}

/*
 * Error() - exit with an error status
 */
void Error(struct lsof_context *ctx) { Exit(ctx, LSOF_EXIT_ERROR); }

#if defined(HASNLIST)
/*
 * get_Nl_value() - get Nl value for nickname
 */

int get_Nl_value(struct lsof_context *ctx, /* context */
                 char *nn,                 /* nickname of requested entry */
                 struct drive_Nl *d,       /* drive_Nl table that built Nl
                                            * (if NULL, use Build_Nl) */
                 KA_T *v)                  /* returned value (if NULL,
                                            * return nothing) */
{
    int i;

    if (!Nl || !Nll)
        return (-1);
    if (!d)
        d = Build_Nl;
    for (i = 0; d->nn; d++, i++) {
        if (strcmp(d->nn, nn) == 0) {
            if (v)
                *v = (KA_T)Nl[i].n_value;
            return (i);
        }
    }
    return (-1);
}
#endif /* defined(HASNLIST) */

/*
 * handleint() - handle an interrupt
 */

#if defined(HASINTSIGNAL)
static int
#else
static void
#endif

/* ARGSUSED */

handleint(int sig) {
    longjmp(Jmp_buf, 1);
}

/*
 * hashbyname() - hash by name
 */

int hashbyname(char *nm, /* pointer to NUL-terminated name */
               int mod)  /* hash modulus */
{
    int i, j;

    for (i = j = 0; *nm; nm++) {
        i ^= (int)*nm << j;
        if (++j > 7)
            j = 0;
    }
    return (((int)(i * 31415)) & (mod - 1));
}

/*
 * is_nw_addr() - is this network address selected?
 */

int is_nw_addr(struct lsof_context *ctx, /* context */
               unsigned char *ia,        /* Internet address */
               int p,                    /* port */
               int af)                   /* address family -- e.g., AF_INET,
                                          * AF_INET6 */
{
    struct nwad *n;

    if (!(n = Nwad))
        return (0);
    for (; n; n = n->next) {
        if (n->proto) {
            if (strcasecmp(n->proto, Lf->iproto) != 0)
                continue;
        }
        if (af && n->af && af != n->af)
            continue;

#if defined(HASIPv6)
        if (af == AF_INET6) {
            if (n->a[15] || n->a[14] || n->a[13] || n->a[12] || n->a[11] ||
                n->a[10] || n->a[9] || n->a[8] || n->a[7] || n->a[6] ||
                n->a[5] || n->a[4] || n->a[3] || n->a[2] || n->a[1] ||
                n->a[0]) {
                if (ia[15] != n->a[15] || ia[14] != n->a[14] ||
                    ia[13] != n->a[13] || ia[12] != n->a[12] ||
                    ia[11] != n->a[11] || ia[10] != n->a[10] ||
                    ia[9] != n->a[9] || ia[8] != n->a[8] || ia[7] != n->a[7] ||
                    ia[6] != n->a[6] || ia[5] != n->a[5] || ia[4] != n->a[4] ||
                    ia[3] != n->a[3] || ia[2] != n->a[2] || ia[1] != n->a[1] ||
                    ia[0] != n->a[0])
                    continue;
            }
        } else if (af == AF_INET)
#endif /* defined(HASIPv6) */

        {
            if (n->a[3] || n->a[2] || n->a[1] || n->a[0]) {
                if (ia[3] != n->a[3] || ia[2] != n->a[2] || ia[1] != n->a[1] ||
                    ia[0] != n->a[0])
                    continue;
            }
        }

#if defined(HASIPv6)
        else
            continue;
#endif /* defined(HASIPv6) */

        if (n->sport == -1 || (p >= n->sport && p <= n->eport)) {
            n->f = 1;
            return (1);
        }
    }
    return (0);
}

/*
 * mkstrcpy() - make a string copy in malloc()'d space
 *
 * return: copy pointer
 *	   copy length (optional)
 */

char *mkstrcpy(char *src,     /* source */
               MALLOC_S *rlp) /* returned length pointer (optional)
                               * The returned length is an strlen()
                               * equivalent */
{
    MALLOC_S len;
    char *ns;

    len = (MALLOC_S)(src ? strlen(src) : 0);
    ns = (char *)malloc(len + 1);
    if (ns) {
        if (src)
            (void)snpf(ns, len + 1, "%s", src);
        else
            *ns = '\0';
    }
    if (rlp)
        *rlp = len;
    return (ns);
}

/*
 * mkstrcat() - make a catenated copy of up to three strings under optional
 *		string-by-string count control
 *
 * return: copy pointer
 *	   copy string length (optional)
 */

char *mkstrcat(char *s1,      /* source string 1 */
               int l1,        /* length of string 1 (-1 if none) */
               char *s2,      /* source string 2 */
               int l2,        /* length of string 2 (-1 if none) */
               char *s3,      /* source string 3 (optional) */
               int l3,        /* length of string 3 (-1 if none) */
               MALLOC_S *clp) /* pointer to return of copy length
                               * (optional) */
{
    MALLOC_S cl, len1, len2, len3;
    char *cp;

    if (s1)
        len1 = (MALLOC_S)((l1 >= 0) ? l1 : strlen(s1));
    else
        len1 = (MALLOC_S)0;
    if (s2)
        len2 = (MALLOC_S)((l2 >= 0) ? l2 : strlen(s2));
    else
        len2 = (MALLOC_S)0;
    if (s3)
        len3 = (MALLOC_S)((l3 >= 0) ? l3 : strlen(s3));
    else
        len3 = (MALLOC_S)0;
    cl = len1 + len2 + len3;
    if ((cp = (char *)malloc(cl + 1))) {
        char *tp = cp;

        if (s1 && len1) {
            (void)strncpy(tp, s1, len1);
            tp += len1;
        }
        if (s2 && len2) {
            (void)strncpy(tp, s2, len2);
            tp += len2;
        }
        if (s3 && len3) {
            (void)strncpy(tp, s3, len3);
            tp += len3;
        }
        *tp = '\0';
    }
    if (clp)
        *clp = cl;
    return (cp);
}

/*
 * is_readable() -- is file readable
 */

int is_readable(struct lsof_context *ctx, /* context */
                char *path,               /* file path */
                int msg)                  /* issue warning message if 1 */
{
    if (access(path, R_OK) < 0) {
        if (!Fwarn && msg == 1)
            (void)fprintf(stderr, ACCESSERRFMT, Pn, path, strerror(errno));
        return (0);
    }
    return (1);
}

/*
 * lstatsafely() - lstat path safely (i. e., with timeout)
 */

int lstatsafely(struct lsof_context *ctx, char *path, /* file path */
                struct stat *buf)                     /* stat buffer address */
{
    if (Fblock) {
        if (!Fwarn)
            (void)fprintf(stderr, "%s: avoiding stat(%s): -b was specified.\n",
                          Pn, path);
        errno = EWOULDBLOCK;
        return (1);
    }
    return (doinchild(ctx, dolstat, path, (char *)buf, sizeof(struct stat)));
}

/*
 * Readlink() - read and interpret file system symbolic links
 */

char *Readlink(struct lsof_context *ctx,
               char *arg) /* argument to be interpreted */
{
    char abuf[MAXPATHLEN + 1];
    int alen;
    char *ap;
    char *argp1, *argp2;
    int i, len, llen, slen;
    char lbuf[MAXPATHLEN + 1];
    char *s1;
    char tbuf[MAXPATHLEN + 1];
    /*
     * See if avoiding kernel blocks.
     */
    if (Fblock) {
        if (!Fwarn) {
            (void)fprintf(stderr, "%s: avoiding readlink(", Pn);
            safestrprt(arg, stderr, 0);
            (void)fprintf(stderr, "): -b was specified.\n");
        }
        Readlink_op = (char *)NULL;
        return mkstrcpy(arg, NULL);
    }
    /*
     * Save the original path.
     */
    if (!Readlink_op)
        Readlink_op = arg;
    /*
     * Evaluate each component of the argument for a symbolic link.
     */
    for (alen = 0, ap = abuf, argp1 = argp2 = arg; *argp2; argp1 = argp2) {
        for (argp2 = argp1 + 1; *argp2 && *argp2 != '/'; argp2++)
            ;
        if ((len = argp2 - arg) >= (int)sizeof(tbuf)) {

        path_too_long:
            if (!Fwarn) {
                (void)fprintf(stderr, "%s: readlink() path too long: ", Pn);
                safestrprt(Readlink_op ? Readlink_op : arg, stderr, 1);
            }
            Readlink_op = (char *)NULL;
            return ((char *)NULL);
        }
        (void)strncpy(tbuf, arg, len);
        tbuf[len] = '\0';
        /*
         * Dereference a symbolic link.
         */
        if ((llen = doinchild(ctx, doreadlink, tbuf, lbuf, sizeof(lbuf) - 1)) >=
            0) {

            /*
             * If the link is a new absolute path, replace
             * the previous assembly with it.
             */
            if (lbuf[0] == '/') {
                (void)strncpy(abuf, lbuf, llen);
                ap = &abuf[llen];
                *ap = '\0';
                alen = llen;
                continue;
            }
            lbuf[llen] = '\0';
            s1 = lbuf;
        } else {
            llen = argp2 - argp1;
            s1 = argp1;
        }
        /*
         * Make sure two components are separated by a `/'.
         *
         * If the first component is not a link, don't force
         * a leading '/'.
         *
         * If the first component is a link and the source of
         * the link has a leading '/', force a leading '/'.
         */
        if (*s1 == '/')
            slen = 1;
        else {
            if (alen > 0) {

                /*
                 * This is not the first component.
                 */
                if (abuf[alen - 1] == '/')
                    slen = 1;
                else
                    slen = 2;
            } else {

                /*
                 * This is the first component.
                 */
                if (s1 == lbuf && tbuf[0] == '/')
                    slen = 2;
                else
                    slen = 1;
            }
        }
        /*
         * Add to the path assembly.
         */
        if ((alen + llen + slen) >= (int)sizeof(abuf))
            goto path_too_long;
        if (slen == 2)
            *ap++ = '/';
        (void)strncpy(ap, s1, llen);
        ap += llen;
        *ap = '\0';
        alen += (llen + slen - 1);
    }
    /*
     * If the assembled path and argument are the same, free all but the
     * last string in the stack, and return the argument.
     */
    if (strcmp(arg, abuf) == 0) {
        for (i = 0; i < Readlink_sx; i++) {
            if (i < (Readlink_sx - 1))
                (void)free((FREE_P *)Readlink_stk[i]);
            Readlink_stk[i] = (char *)NULL;
        }
        Readlink_sx = 0;
        Readlink_op = (char *)NULL;
        return mkstrcpy(arg, NULL);
    }
    /*
     * If the assembled path and argument are different, add it to the
     * string stack, then Readlink() it.
     */
    if (!(s1 = mkstrcpy(abuf, (MALLOC_S *)NULL))) {

    no_readlink_space:

        (void)fprintf(stderr, "%s: no Readlink string space for ", Pn);
        safestrprt(abuf, stderr, 1);
        Error(ctx);
    }
    if (Readlink_sx >= MAXSYMLINKS) {

        /*
         * If there are too many symbolic links, report an error, clear
         * the stack, and return no path.
         */
        if (!Fwarn) {
            (void)fprintf(
                stderr,
                "%s: too many (> %d) symbolic links in readlink() path: ", Pn,
                MAXSYMLINKS);
            safestrprt(Readlink_op ? Readlink_op : arg, stderr, 1);
        }
        for (i = 0; i < Readlink_sx; i++) {
            (void)free((FREE_P *)Readlink_stk[i]);
            Readlink_stk[i] = (char *)NULL;
        }
        (void)free((FREE_P *)Readlink_stk);
        (void)free((FREE_P *)s1);
        Readlink_stk = (char **)NULL;
        Readlink_ss = Readlink_sx = 0;
        s1 = (char *)NULL;
        Readlink_op = (char *)NULL;
        return ((char *)NULL);
    }
    if (++Readlink_sx > Readlink_ss) {
        if (!Readlink_stk)
            Readlink_stk =
                (char **)malloc((MALLOC_S)(sizeof(char *) * Readlink_sx));
        else
            Readlink_stk =
                (char **)realloc((MALLOC_P *)Readlink_stk,
                                 (MALLOC_S)(sizeof(char *) * Readlink_sx));
        if (!Readlink_stk)
            goto no_readlink_space;
        Readlink_ss = Readlink_sx;
    }
    Readlink_stk[Readlink_sx - 1] = s1;
    return (Readlink(ctx, s1));
}

#if defined(HASSTREAMS)
/*
 * readstdata() - read stream's stdata structure
 */

int readstdata(struct lsof_context *ctx, /* context */
               KA_T addr,                /* stdata address in kernel*/
               struct stdata *buf)       /* buffer address */
{
    if (!addr || kread(ctx, addr, (char *)buf, sizeof(struct stdata))) {
        (void)snpf(Namech, Namechl, "no stream data in %s",
                   print_kptr(addr, (char *)NULL, 0));
        return (1);
    }
    return (0);
}

/*
 * readsthead() - read stream head
 */

int readsthead(struct lsof_context *ctx, /* context */
               KA_T addr,                /* starting queue pointer in kernel */
               struct queue *buf)        /* buffer for queue head */
{
    KA_T qp;

    if (!addr) {
        (void)snpf(Namech, Namechl, "no stream queue head");
        return (1);
    }
    for (qp = addr; qp; qp = (KA_T)buf->q_next) {
        if (kread(ctx, qp, (char *)buf, sizeof(struct queue))) {
            (void)snpf(Namech, Namechl, "bad stream queue link at %s",
                       print_kptr(qp, (char *)NULL, 0));
            return (1);
        }
    }
    return (0);
}

/*
 * readstidnm() - read stream module ID name
 */

int readstidnm(struct lsof_context *ctx, /* context */
               KA_T addr,                /* module ID name address in kernel */
               char *buf,                /* receiving buffer address */
               READLEN_T len)            /* buffer length */
{
    if (!addr || kread(ctx, addr, buf, len)) {
        (void)snpf(Namech, Namechl, "can't read module ID name from %s",
                   print_kptr(addr, (char *)NULL, 0));
        return (1);
    }
    return (0);
}

/*
 * readstmin() - read stream's module info
 */

int readstmin(struct lsof_context *ctx, /* context */
              KA_T addr,                /* module info address in kernel */
              struct module_info *buf)  /* receiving buffer address */
{
    if (!addr || kread(ctx, addr, (char *)buf, sizeof(struct module_info))) {
        (void)snpf(Namech, Namechl, "can't read module info from %s",
                   print_kptr(addr, (char *)NULL, 0));
        return (1);
    }
    return (0);
}

/*
 * readstqinit() - read stream's queue information structure
 */

int readstqinit(struct lsof_context *ctx, /* context */
                KA_T addr,                /* queue info address in kernel */
                struct qinit *buf)        /* receiving buffer address */
{
    if (!addr || kread(ctx, addr, (char *)buf, sizeof(struct qinit))) {
        (void)snpf(Namech, Namechl, "can't read queue info from %s",
                   print_kptr(addr, (char *)NULL, 0));
        return (1);
    }
    return (0);
}
#endif /* HASSTREAMS */

/*
 * safepup() - safely print an unprintable character -- i.e., print it in a
 *	       printable form
 *
 * return: char * to printable equivalent
 *	   cl = strlen(printable equivalent)
 */

char *safepup(unsigned int c, /* unprintable (i.e., !isprint())
                               * character  and '\\' */
              int *cl)        /* returned printable strlen -- NULL if
                               * no return needed */
{
    int len;
    char *rp;
    static char up[8];

    if (c < 0x20) {
        switch (c) {
        case '\b':
            rp = "\\b";
            break;
        case '\f':
            rp = "\\f";
            break;
        case '\n':
            rp = "\\n";
            break;
        case '\r':
            rp = "\\r";
            break;
        case '\t':
            rp = "\\t";
            break;
        default:
            (void)snpf(up, sizeof(up), "^%c", c + 0x40);
            rp = up;
        }
        len = 2;
    } else if (c == 0xff) {
        rp = "^?";
        len = 2;
    } else if (c == '\\') {
        rp = "\\\\";
        len = 2;
    } else {
        (void)snpf(up, sizeof(up), "\\x%02x", (int)(c & 0xff));
        rp = up;
        len = 4;
    }
    if (cl)
        *cl = len;
    return (rp);
}

/*
 * safestrlen() - calculate a "safe" string length -- i.e., compute space for
 *		  non-printable characters when printed in a printable form
 */

int safestrlen(char *sp,  /* string pointer */
               int flags) /* flags:
                           *   bit 0: 0 (0) = no NL
                           *	    1 (1) = add trailing NL
                           *	 1: 0 (0) = ' ' printable
                           *	    1 (2) = ' ' not printable
                           */
{
    char c;
    int len = 0;

    c = (flags & 2) ? ' ' : '\0';
    if (sp) {
        for (; *sp; sp++) {
            if (!isprint((unsigned char)*sp) || (*sp == '\\') || (*sp == c)) {
                if ((*sp < 0x20) || ((unsigned char)*sp == 0xff) ||
                    (*sp == '\\'))
                    len += 2; /* length of \. or ^. form */
                else
                    len += 4; /* length of "\x%02x" printf */
            } else
                len++;
        }
    }
    return (len);
}

/*
 * safestrprt() - print a string "safely" to the indicated stream -- i.e.,
 *		  print unprintable characters in a printable form
 */
void safestrprt(char *sp,  /* string to print pointer pointer */
                FILE *fs,  /* destination stream -- e.g., stderr
                            * or stdout */
                int flags) /* flags:
                            *   bit 0: 0 (0) = no NL
                            *	    1 (1) = add trailing NL
                            *	 1: 0 (0) = ' ' printable
                            *	    1 (2) = ' ' not printable
                            *	 2: 0 (0) = print string as is
                            *	    1 (4) = surround string
                            *		    with '"'
                            *	 4: 0 (0) = print ending '\n'
                            *	    1 (8) = don't print ending
                            *		    '\n'
                            */
{
    char c;
    int lnc, lnt, sl;

#if defined(HASWIDECHAR)
    wchar_t w;
    int wcmx = MB_CUR_MAX;
#else  /* !defined(HASWIDECHAR) */
    static int wcmx = 1;
#endif /* defined(HASWIDECHAR) */

    c = (flags & 2) ? ' ' : '\0';
    if (flags & 4)
        putc('"', fs);
    if (sp) {
        for (sl = strlen(sp); *sp; sl -= lnc, sp += lnc) {

#if defined(HASWIDECHAR)
            if (wcmx > 1) {
                lnc = mblen(sp, sl);
                if (lnc > 1) {
                    if ((mbtowc(&w, sp, sl) == lnc) && iswprint(w)) {
                        for (lnt = 0; lnt < lnc; lnt++) {
                            putc((int)*(sp + lnt), fs);
                        }
                    } else {
                        for (lnt = 0; lnt < lnc; lnt++) {
                            fputs(
                                safepup((unsigned int)*(sp + lnt), (int *)NULL),
                                fs);
                        }
                    }
                    continue;
                } else
                    lnc = 1;
            } else
                lnc = 1;
#else  /* !defined(HASWIDECHAR) */
            lnc = 1;
#endif /* defined(HASWIDECHAR) */

            if ((*sp != '\\') && isprint((unsigned char)*sp) && *sp != c)
                putc((int)(*sp & 0xff), fs);
            else {
                if ((flags & 8) && (*sp == '\n') && !*(sp + 1))
                    break;
                fputs(safepup((unsigned int)*sp, (int *)NULL), fs);
            }
        }
    }
    if (flags & 4)
        putc('"', fs);
    if (flags & 1)
        putc('\n', fs);
}

/*
 * safestrprtn() - print a specified number of characters from a string
 *		   "safely" to the indicated stream
 */

void safestrprtn(char *sp,  /* string to print pointer pointer */
                 int len,   /* safe number of characters to
                             * print */
                 FILE *fs,  /* destination stream -- e.g., stderr
                             * or stdout */
                 int flags) /* flags:
                             *   bit 0: 0 (0) = no NL
                             *	    1 (1) = add trailing NL
                             *	 1: 0 (0) = ' ' printable
                             *	    1 (2) = ' ' not printable
                             *	 2: 0 (0) = print string as is
                             *	    1 (4) = surround string
                             *		    with '"'
                             *	 4: 0 (0) = print ending '\n'
                             *	    1 (8) = don't print ending
                             *		    '\n'
                             */
{
    char c, *up;
    int cl, i;

    if (flags & 4)
        putc('"', fs);
    if (sp) {
        c = (flags & 2) ? ' ' : '\0';
        for (i = 0; i < len && *sp; sp++) {
            if ((*sp != '\\') && isprint((unsigned char)*sp) && *sp != c) {
                putc((int)(*sp & 0xff), fs);
                i++;
            } else {
                if ((flags & 8) && (*sp == '\n') && !*(sp + 1))
                    break;
                up = safepup((unsigned int)*sp, &cl);
                if ((i + cl) > len)
                    break;
                fputs(up, fs);
                i += cl;
            }
        }
    } else
        i = 0;
    for (; i < len; i++)
        putc(' ', fs);
    if (flags & 4)
        putc('"', fs);
    if (flags & 1)
        putc('\n', fs);
}

/*
 * statsafely() - stat path safely (i. e., with timeout)
 */

int statsafely(struct lsof_context *ctx, char *path, /* file path */
               struct stat *buf)                     /* stat buffer address */
{
    if (Fblock) {
        if (!Fwarn)
            (void)fprintf(stderr, "%s: avoiding stat(%s): -b was specified.\n",
                          Pn, path);
        errno = EWOULDBLOCK;
        return (1);
    }
    return (doinchild(ctx, dostat, path, (char *)buf, sizeof(struct stat)));
}

/*
 * stkdir() - stack directory name
 */

void stkdir(struct lsof_context *ctx, char *p) /* directory path */
{
    MALLOC_S len;
    /*
     * Provide adequate space for directory stack pointers.
     */
    if (Dstkx >= Dstkn) {
        Dstkn += 128;
        len = (MALLOC_S)(Dstkn * sizeof(char *));
        if (!Dstk)
            Dstk = (char **)malloc(len);
        else
            Dstk = (char **)realloc((MALLOC_P *)Dstk, len);
        if (!Dstk) {
            (void)fprintf(stderr, "%s: no space for directory stack at: ", Pn);
            safestrprt(p, stderr, 1);
            Error(ctx);
        }
    }
    /*
     * Allocate space for the name, copy it there and put its pointer on the
     * stack.
     */
    if (!(Dstk[Dstkx] = mkstrcpy(p, (MALLOC_S *)NULL))) {
        (void)fprintf(stderr, "%s: no space for: ", Pn);
        safestrprt(p, stderr, 1);
        Error(ctx);
    }
    Dstkx++;
}

/*
 * x2dev() - convert hexadecimal ASCII string to device number
 */

char *x2dev(char *s,  /* ASCII string */
            dev_t *d) /* device receptacle */
{
    char *cp, *cp1;
    int n;
    dev_t r;

    /*
     * Skip an optional leading 0x.  Count the number of hex digits up to the
     * end of the string, or to a space, or to a comma.  Return an error if an
     * unknown character is encountered.  If the count is larger than (2 *
     * sizeof(dev_t))
     * -- e.g., because of sign extension -- ignore excess leading hex 0xf
     * digits, but return an error if an excess leading digit isn't 0xf.
     */
    if (strncasecmp(s, "0x", 2) == 0)
        s += 2;
    for (cp = s, n = 0; *cp; cp++, n++) {
        if (isdigit((unsigned char)*cp))
            continue;
        if ((unsigned char)*cp >= 'a' && (unsigned char)*cp <= 'f')
            continue;
        if ((unsigned char)*cp >= 'A' && (unsigned char)*cp <= 'F')
            continue;
        if (*cp == ' ' || *cp == ',')
            break;
        return ((char *)NULL);
    }
    if (!n)
        return ((char *)NULL);
    if (n > (2 * (int)sizeof(dev_t))) {
        cp1 = s;
        s += (n - (2 * sizeof(dev_t)));
        while (cp1 < s) {
            if (*cp1 != 'f' && *cp1 != 'F')
                return ((char *)NULL);
            cp1++;
        }
    }
    /*
     * Assemble the validated hex digits of the device number, starting at a
     * point in the string relevant to sizeof(dev_t).
     */
    for (r = 0; s < cp; s++) {
        r = r << 4;
        if (isdigit((unsigned char)*s))
            r |= (unsigned char)(*s - '0') & 0xf;
        else {
            if (isupper((unsigned char)*s))
                r |= ((unsigned char)(*s - 'A') + 10) & 0xf;
            else
                r |= ((unsigned char)(*s - 'a') + 10) & 0xf;
        }
    }
    *d = r;
    return (s);
}

/*
 * grow_array(): handle dynamic array growth
 */
int grow_array(void **array_ptr, int *cap, size_t elem_size, int growth_count) {
    void *new_array;

    /* Calculate new capacity */
    int new_capacity = *cap + growth_count;
    if (new_capacity < 0) {
        return -1;
    }
    size_t new_size = (size_t)new_capacity * elem_size;

    /* Check for overflow */
    if (new_capacity < 0 || new_size / elem_size != (size_t)new_capacity) {
        return -1;
    }

    if (*array_ptr) {
        new_array = realloc((MALLOC_P *)*array_ptr, (MALLOC_S)new_size);
    } else {
        new_array = malloc((MALLOC_S)new_size);
    }

    if (!new_array) {
        /* Allocation failed */
        return -1;
    }

    *array_ptr = new_array;
    *cap = new_capacity;
    return 0;
}