]> git.saurik.com Git - apple/libc.git/blobdiff - gen/getcap.c
Libc-262.tar.gz
[apple/libc.git] / gen / getcap.c
diff --git a/gen/getcap.c b/gen/getcap.c
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@@ -0,0 +1,1064 @@
+/*
+ * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
+ * 
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+/*-
+ * Copyright (c) 1992, 1993
+ *     The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Casey Leedom of Lawrence Livermore National Laboratory.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char rcsid[] = "$OpenBSD: getcap.c,v 1.4 1997/02/01 04:35:33 deraadt Exp $";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/types.h>
+
+#include <ctype.h>
+#include <db.h>
+#include <errno.h>     
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define        BFRAG           1024
+#define        BSIZE           1024
+#define        ESC             ('[' & 037)     /* ASCII ESC */
+#define        MAX_RECURSION   32              /* maximum getent recursion */
+#define        SFRAG           100             /* cgetstr mallocs in SFRAG chunks */
+
+#define RECOK  (char)0
+#define TCERR  (char)1
+#define        SHADOW  (char)2
+
+static size_t   topreclen;     /* toprec length */
+static char    *toprec;        /* Additional record specified by cgetset() */
+static int      gottoprec;     /* Flag indicating retrieval of toprecord */
+
+static int     cdbget __P((DB *, char **, char *));
+static int     getent __P((char **, u_int *, char **, int, char *, int, char *));
+static int     nfcmp __P((char *, char *));
+
+/*
+ * Cgetset() allows the addition of a user specified buffer to be added
+ * to the database array, in effect "pushing" the buffer on top of the
+ * virtual database. 0 is returned on success, -1 on failure.
+ */
+int
+cgetset(ent)
+       char *ent;
+{
+       if (ent == NULL) {
+               if (toprec)
+                       free(toprec);
+                toprec = NULL;
+                topreclen = 0;
+                return (0);
+        }
+        topreclen = strlen(ent);
+        if ((toprec = malloc (topreclen + 1)) == NULL) {
+               errno = ENOMEM;
+                return (-1);
+       }
+       gottoprec = 0;
+        (void)strcpy(toprec, ent);
+        return (0);
+}
+
+/*
+ * Cgetcap searches the capability record buf for the capability cap with
+ * type `type'.  A pointer to the value of cap is returned on success, NULL
+ * if the requested capability couldn't be found.
+ *
+ * Specifying a type of ':' means that nothing should follow cap (:cap:).
+ * In this case a pointer to the terminating ':' or NUL will be returned if
+ * cap is found.
+ *
+ * If (cap, '@') or (cap, terminator, '@') is found before (cap, terminator)
+ * return NULL.
+ */
+char *
+cgetcap(buf, cap, type)
+       char *buf, *cap;
+       int type;
+{
+       register char *bp, *cp;
+
+       bp = buf;
+       for (;;) {
+               /*
+                * Skip past the current capability field - it's either the
+                * name field if this is the first time through the loop, or
+                * the remainder of a field whose name failed to match cap.
+                */
+               for (;;)
+                       if (*bp == '\0')
+                               return (NULL);
+                       else
+                               if (*bp++ == ':')
+                                       break;
+
+               /*
+                * Try to match (cap, type) in buf.
+                */
+               for (cp = cap; *cp == *bp && *bp != '\0'; cp++, bp++)
+                       continue;
+               if (*cp != '\0')
+                       continue;
+               if (*bp == '@')
+                       return (NULL);
+               if (type == ':') {
+                       if (*bp != '\0' && *bp != ':')
+                               continue;
+                       return(bp);
+               }
+               if (*bp != type)
+                       continue;
+               bp++;
+               return (*bp == '@' ? NULL : bp);
+       }
+       /* NOTREACHED */
+}
+
+/*
+ * Cgetent extracts the capability record name from the NULL terminated file
+ * array db_array and returns a pointer to a malloc'd copy of it in buf.
+ * Buf must be retained through all subsequent calls to cgetcap, cgetnum,
+ * cgetflag, and cgetstr, but may then be free'd.  0 is returned on success,
+ * -1 if the requested record couldn't be found, -2 if a system error was
+ * encountered (couldn't open/read a file, etc.), and -3 if a potential
+ * reference loop is detected.
+ */
+int
+cgetent(buf, db_array, name)
+       char **buf, **db_array, *name;
+{
+       u_int dummy;
+
+       return (getent(buf, &dummy, db_array, -1, name, 0, NULL));
+}
+
+/*
+ * Getent implements the functions of cgetent.  If fd is non-negative,
+ * *db_array has already been opened and fd is the open file descriptor.  We
+ * do this to save time and avoid using up file descriptors for tc=
+ * recursions.
+ *
+ * Getent returns the same success/failure codes as cgetent.  On success, a
+ * pointer to a malloc'ed capability record with all tc= capabilities fully
+ * expanded and its length (not including trailing ASCII NUL) are left in
+ * *cap and *len.
+ *
+ * Basic algorithm:
+ *     + Allocate memory incrementally as needed in chunks of size BFRAG
+ *       for capability buffer.
+ *     + Recurse for each tc=name and interpolate result.  Stop when all
+ *       names interpolated, a name can't be found, or depth exceeds
+ *       MAX_RECURSION.
+ */
+static int
+getent(cap, len, db_array, fd, name, depth, nfield)
+       char **cap, **db_array, *name, *nfield;
+       u_int *len;
+       int fd, depth;
+{
+       DB *capdbp;
+       register char *r_end, *rp, **db_p;
+       int myfd, eof, foundit, retval, clen;
+       char *record, *cbuf;
+       int tc_not_resolved;
+       char pbuf[_POSIX_PATH_MAX];
+       
+       /*
+        * Return with ``loop detected'' error if we've recursed more than
+        * MAX_RECURSION times.
+        */
+       if (depth > MAX_RECURSION)
+               return (-3);
+
+       /*
+        * Check if we have a top record from cgetset().
+         */
+       if (depth == 0 && toprec != NULL && cgetmatch(toprec, name) == 0) {
+               if ((record = malloc (topreclen + BFRAG)) == NULL) {
+                       errno = ENOMEM;
+                       return (-2);
+               }
+               (void)strcpy(record, toprec);
+               myfd = 0;
+               db_p = db_array;
+               rp = record + topreclen + 1;
+               r_end = rp + BFRAG;
+               goto tc_exp;
+       }
+       /*
+        * Allocate first chunk of memory.
+        */
+       if ((record = malloc(BFRAG)) == NULL) {
+               errno = ENOMEM;
+               return (-2);
+       }
+       r_end = record + BFRAG;
+       foundit = 0;
+       /*
+        * Loop through database array until finding the record.
+        */
+
+       for (db_p = db_array; *db_p != NULL; db_p++) {
+               eof = 0;
+
+               /*
+                * Open database if not already open.
+                */
+
+               if (fd >= 0) {
+                       (void)lseek(fd, (off_t)0, SEEK_SET);
+                       myfd = 0;
+               } else {
+                       (void)snprintf(pbuf, sizeof(pbuf), "%s.db", *db_p);
+                       if ((capdbp = dbopen(pbuf, O_RDONLY, 0, DB_HASH, 0))
+                            != NULL) {
+                               free(record);
+                               retval = cdbget(capdbp, &record, name);
+                               if (retval < 0) {
+                                       /* no record available */
+                                       (void)capdbp->close(capdbp);
+                                       return (retval);
+                               }
+                               /* save the data; close frees it */
+                               clen = strlen(record);
+                               cbuf = malloc(clen + 1);
+                               memcpy(cbuf, record, clen + 1);
+                               if (capdbp->close(capdbp) < 0) {
+                                       free(cbuf);
+                                       return (-2);
+                               }
+                               *len = clen;
+                               *cap = cbuf;
+                               return (retval);
+                       } else {
+                               fd = open(*db_p, O_RDONLY, 0);
+                               if (fd < 0) {
+                                       /* No error on unfound file. */
+                                       continue;
+                               }
+                               myfd = 1;
+                       }
+               }
+               /*
+                * Find the requested capability record ...
+                */
+               {
+               char buf[BUFSIZ];
+               register char *b_end, *bp;
+               register int c;
+
+               /*
+                * Loop invariants:
+                *      There is always room for one more character in record.
+                *      R_end always points just past end of record.
+                *      Rp always points just past last character in record.
+                *      B_end always points just past last character in buf.
+                *      Bp always points at next character in buf.
+                */
+               b_end = buf;
+               bp = buf;
+               for (;;) {
+
+                       /*
+                        * Read in a line implementing (\, newline)
+                        * line continuation.
+                        */
+                       rp = record;
+                       for (;;) {
+                               if (bp >= b_end) {
+                                       int n;
+               
+                                       n = read(fd, buf, sizeof(buf));
+                                       if (n <= 0) {
+                                               if (myfd)
+                                                       (void)close(fd);
+                                               if (n < 0) {
+                                                       free(record);
+                                                       return (-2);
+                                               } else {
+                                                       fd = -1;
+                                                       eof = 1;
+                                                       break;
+                                               }
+                                       }
+                                       b_end = buf+n;
+                                       bp = buf;
+                               }
+       
+                               c = *bp++;
+                               if (c == '\n') {
+                                       if (rp > record && *(rp-1) == '\\') {
+                                               rp--;
+                                               continue;
+                                       } else
+                                               break;
+                               }
+                               *rp++ = c;
+
+                               /*
+                                * Enforce loop invariant: if no room 
+                                * left in record buffer, try to get
+                                * some more.
+                                */
+                               if (rp >= r_end) {
+                                       u_int pos;
+                                       size_t newsize;
+
+                                       pos = rp - record;
+                                       newsize = r_end - record + BFRAG;
+                                       record = realloc(record, newsize);
+                                       if (record == NULL) {
+                                               errno = ENOMEM;
+                                               if (myfd)
+                                                       (void)close(fd);
+                                               return (-2);
+                                       }
+                                       r_end = record + newsize;
+                                       rp = record + pos;
+                               }
+                       }
+                               /* loop invariant let's us do this */
+                       *rp++ = '\0';
+
+                       /*
+                        * If encountered eof check next file.
+                        */
+                       if (eof)
+                               break;
+                               
+                       /*
+                        * Toss blank lines and comments.
+                        */
+                       if (*record == '\0' || *record == '#')
+                               continue;
+       
+                       /*
+                        * See if this is the record we want ...
+                        */
+                       if (cgetmatch(record, name) == 0) {
+                               if (nfield == NULL || !nfcmp(nfield, record)) {
+                                       foundit = 1;
+                                       break;  /* found it! */
+                               }
+                       }
+               }
+       }
+               if (foundit)
+                       break;
+       }
+
+       if (!foundit) {
+               free(record);
+               return (-1);
+       }
+
+       /*
+        * Got the capability record, but now we have to expand all tc=name
+        * references in it ...
+        */
+tc_exp:        {
+               register char *newicap, *s;
+               register int newilen;
+               u_int ilen;
+               int diff, iret, tclen;
+               char *icap, *scan, *tc, *tcstart, *tcend;
+
+               /*
+                * Loop invariants:
+                *      There is room for one more character in record.
+                *      R_end points just past end of record.
+                *      Rp points just past last character in record.
+                *      Scan points at remainder of record that needs to be
+                *      scanned for tc=name constructs.
+                */
+               scan = record;
+               tc_not_resolved = 0;
+               for (;;) {
+                       if ((tc = cgetcap(scan, "tc", '=')) == NULL)
+                               break;
+
+                       /*
+                        * Find end of tc=name and stomp on the trailing `:'
+                        * (if present) so we can use it to call ourselves.
+                        */
+                       s = tc;
+                       for (;;)
+                               if (*s == '\0')
+                                       break;
+                               else
+                                       if (*s++ == ':') {
+                                               *(s - 1) = '\0';
+                                               break;
+                                       }
+                       tcstart = tc - 3;
+                       tclen = s - tcstart;
+                       tcend = s;
+
+                       iret = getent(&icap, &ilen, db_p, fd, tc, depth+1, 
+                                     NULL);
+                       newicap = icap;         /* Put into a register. */
+                       newilen = ilen;
+                       if (iret != 0) {
+                               /* an error */
+                               if (iret < -1) {
+                                       if (myfd)
+                                               (void)close(fd);
+                                       free(record);
+                                       return (iret);
+                               }
+                               if (iret == 1)
+                                       tc_not_resolved = 1;
+                               /* couldn't resolve tc */
+                               if (iret == -1) {
+                                       *(s - 1) = ':';                 
+                                       scan = s - 1;
+                                       tc_not_resolved = 1;
+                                       continue;
+                                       
+                               }
+                       }
+                       /* not interested in name field of tc'ed record */
+                       s = newicap;
+                       for (;;)
+                               if (*s == '\0')
+                                       break;
+                               else
+                                       if (*s++ == ':')
+                                               break;
+                       newilen -= s - newicap;
+                       newicap = s;
+
+                       /* make sure interpolated record is `:'-terminated */
+                       s += newilen;
+                       if (*(s-1) != ':') {
+                               *s = ':';       /* overwrite NUL with : */
+                               newilen++;
+                       }
+
+                       /*
+                        * Make sure there's enough room to insert the
+                        * new record.
+                        */
+                       diff = newilen - tclen;
+                       if (diff >= r_end - rp) {
+                               u_int pos, tcpos, tcposend;
+                               size_t newsize;
+
+                               pos = rp - record;
+                               newsize = r_end - record + diff + BFRAG;
+                               tcpos = tcstart - record;
+                               tcposend = tcend - record;
+                               record = realloc(record, newsize);
+                               if (record == NULL) {
+                                       errno = ENOMEM;
+                                       if (myfd)
+                                               (void)close(fd);
+                                       free(icap);
+                                       return (-2);
+                               }
+                               r_end = record + newsize;
+                               rp = record + pos;
+                               tcstart = record + tcpos;
+                               tcend = record + tcposend;
+                       }
+
+                       /*
+                        * Insert tc'ed record into our record.
+                        */
+                       s = tcstart + newilen;
+                       bcopy(tcend, s, rp - tcend);
+                       bcopy(newicap, tcstart, newilen);
+                       rp += diff;
+                       free(icap);
+
+                       /*
+                        * Start scan on `:' so next cgetcap works properly
+                        * (cgetcap always skips first field).
+                        */
+                       scan = s-1;
+               }
+       
+       }
+       /*
+        * Close file (if we opened it), give back any extra memory, and
+        * return capability, length and success.
+        */
+       if (myfd)
+               (void)close(fd);
+       *len = rp - record - 1; /* don't count NUL */
+       if (r_end > rp)
+               if ((record = 
+                    realloc(record, (size_t)(rp - record))) == NULL) {
+                       errno = ENOMEM;
+                       return (-2);
+               }
+               
+       *cap = record;
+       if (tc_not_resolved)
+               return (1);
+       return (0);
+}      
+
+static int
+cdbget(capdbp, bp, name)
+       DB *capdbp;
+       char **bp, *name;
+{
+       DBT key, data;
+
+       key.data = name;
+       key.size = strlen(name);
+
+       for (;;) {
+               /* Get the reference. */
+               switch(capdbp->get(capdbp, &key, &data, 0)) {
+               case -1:
+                       return (-2);
+               case 1:
+                       return (-1);
+               }
+
+               /* If not an index to another record, leave. */
+               if (((char *)data.data)[0] != SHADOW)
+                       break;
+
+               key.data = (char *)data.data + 1;
+               key.size = data.size - 1;
+       }
+       
+       *bp = (char *)data.data + 1;
+       return (((char *)(data.data))[0] == TCERR ? 1 : 0);
+}
+
+/*
+ * Cgetmatch will return 0 if name is one of the names of the capability
+ * record buf, -1 if not.
+ */
+int
+cgetmatch(buf, name)
+       char *buf, *name;
+{
+       register char *np, *bp;
+
+       /*
+        * Start search at beginning of record.
+        */
+       bp = buf;
+       for (;;) {
+               /*
+                * Try to match a record name.
+                */
+               np = name;
+               for (;;)
+                       if (*np == '\0')
+                               if (*bp == '|' || *bp == ':' || *bp == '\0')
+                                       return (0);
+                               else
+                                       break;
+                       else
+                               if (*bp++ != *np++)
+                                       break;
+
+               /*
+                * Match failed, skip to next name in record.
+                */
+               bp--;   /* a '|' or ':' may have stopped the match */
+               for (;;)
+                       if (*bp == '\0' || *bp == ':')
+                               return (-1);    /* match failed totally */
+                       else
+                               if (*bp++ == '|')
+                                       break;  /* found next name */
+       }
+}
+
+
+
+
+
+int
+cgetfirst(buf, db_array)
+       char **buf, **db_array;
+{
+       (void)cgetclose();
+       return (cgetnext(buf, db_array));
+}
+
+static FILE *pfp;
+static int slash;
+static char **dbp;
+
+int
+cgetclose()
+{
+       if (pfp != NULL) {
+               (void)fclose(pfp);
+               pfp = NULL;
+       }
+       dbp = NULL;
+       gottoprec = 0;
+       slash = 0;
+       return(0);
+}
+
+/*
+ * Cgetnext() gets either the first or next entry in the logical database 
+ * specified by db_array.  It returns 0 upon completion of the database, 1
+ * upon returning an entry with more remaining, and -1 if an error occurs.
+ */
+int
+cgetnext(bp, db_array)
+        register char **bp;
+       char **db_array;
+{
+       size_t len;
+       int status, done;
+       char *cp, *line, *rp, *np, buf[BSIZE], nbuf[BSIZE];
+       u_int dummy;
+
+       if (dbp == NULL)
+               dbp = db_array;
+
+       if (pfp == NULL && (pfp = fopen(*dbp, "r")) == NULL) {
+               (void)cgetclose();
+               return (-1);
+       }
+       for(;;) {
+               if (toprec && !gottoprec) {
+                       gottoprec = 1;
+                       line = toprec;
+               } else {
+                       line = fgetln(pfp, &len);
+                       if (line == NULL && pfp) {
+                               (void)fclose(pfp);
+                               if (ferror(pfp)) {
+                                       (void)cgetclose();
+                                       return (-1);
+                               } else {
+                                       if (*++dbp == NULL) {
+                                               (void)cgetclose();
+                                               return (0);
+                                       } else if ((pfp =
+                                           fopen(*dbp, "r")) == NULL) {
+                                               (void)cgetclose();
+                                               return (-1);
+                                       } else
+                                               continue;
+                               }
+                       } else
+                               line[len - 1] = '\0';
+                       if (len == 1) {
+                               slash = 0;
+                               continue;
+                       }
+                       if (isspace(*line) ||
+                           *line == ':' || *line == '#' || slash) {
+                               if (line[len - 2] == '\\')
+                                       slash = 1;
+                               else
+                                       slash = 0;
+                               continue;
+                       }
+                       if (line[len - 2] == '\\')
+                               slash = 1;
+                       else
+                               slash = 0;
+               }                       
+
+
+               /* 
+                * Line points to a name line.
+                */
+               done = 0;
+               np = nbuf;
+               for (;;) {
+                       for (cp = line; *cp != '\0'; cp++) {
+                               if (*cp == ':') {
+                                       *np++ = ':';
+                                       done = 1;
+                                       break;
+                               }
+                               if (*cp == '\\')
+                                       break;
+                               *np++ = *cp;
+                       }
+                       if (done) {
+                               *np = '\0';
+                               break;
+                       } else { /* name field extends beyond the line */
+                               line = fgetln(pfp, &len);
+                               if (line == NULL && pfp) {
+                                       (void)fclose(pfp);
+                                       if (ferror(pfp)) {
+                                               (void)cgetclose();
+                                               return (-1);
+                                       }
+                               } else
+                                       line[len - 1] = '\0';
+                       }
+               }
+               rp = buf;
+               for(cp = nbuf; *cp != NULL; cp++)
+                       if (*cp == '|' || *cp == ':')
+                               break;
+                       else
+                               *rp++ = *cp;
+
+               *rp = '\0';
+               /* 
+                * XXX 
+                * Last argument of getent here should be nbuf if we want true
+                * sequential access in the case of duplicates.  
+                * With NULL, getent will return the first entry found
+                * rather than the duplicate entry record.  This is a 
+                * matter of semantics that should be resolved.
+                */
+               status = getent(bp, &dummy, db_array, -1, buf, 0, NULL);
+               if (status == -2 || status == -3)
+                       (void)cgetclose();
+
+               return (status + 1);
+       }
+       /* NOTREACHED */
+}
+
+/*
+ * Cgetstr retrieves the value of the string capability cap from the
+ * capability record pointed to by buf.  A pointer to a decoded, NUL
+ * terminated, malloc'd copy of the string is returned in the char *
+ * pointed to by str.  The length of the string not including the trailing
+ * NUL is returned on success, -1 if the requested string capability
+ * couldn't be found, -2 if a system error was encountered (storage
+ * allocation failure).
+ */
+int
+cgetstr(buf, cap, str)
+       char *buf, *cap;
+       char **str;
+{
+       register u_int m_room;
+       register char *bp, *mp;
+       int len;
+       char *mem;
+
+       /*
+        * Find string capability cap
+        */
+       bp = cgetcap(buf, cap, '=');
+       if (bp == NULL)
+               return (-1);
+
+       /*
+        * Conversion / storage allocation loop ...  Allocate memory in
+        * chunks SFRAG in size.
+        */
+       if ((mem = malloc(SFRAG)) == NULL) {
+               errno = ENOMEM;
+               return (-2);    /* couldn't even allocate the first fragment */
+       }
+       m_room = SFRAG;
+       mp = mem;
+
+       while (*bp != ':' && *bp != '\0') {
+               /*
+                * Loop invariants:
+                *      There is always room for one more character in mem.
+                *      Mp always points just past last character in mem.
+                *      Bp always points at next character in buf.
+                */
+               if (*bp == '^') {
+                       bp++;
+                       if (*bp == ':' || *bp == '\0')
+                               break;  /* drop unfinished escape */
+                       *mp++ = *bp++ & 037;
+               } else if (*bp == '\\') {
+                       bp++;
+                       if (*bp == ':' || *bp == '\0')
+                               break;  /* drop unfinished escape */
+                       if ('0' <= *bp && *bp <= '7') {
+                               register int n, i;
+
+                               n = 0;
+                               i = 3;  /* maximum of three octal digits */
+                               do {
+                                       n = n * 8 + (*bp++ - '0');
+                               } while (--i && '0' <= *bp && *bp <= '7');
+                               *mp++ = n;
+                       }
+                       else switch (*bp++) {
+                               case 'b': case 'B':
+                                       *mp++ = '\b';
+                                       break;
+                               case 't': case 'T':
+                                       *mp++ = '\t';
+                                       break;
+                               case 'n': case 'N':
+                                       *mp++ = '\n';
+                                       break;
+                               case 'f': case 'F':
+                                       *mp++ = '\f';
+                                       break;
+                               case 'r': case 'R':
+                                       *mp++ = '\r';
+                                       break;
+                               case 'e': case 'E':
+                                       *mp++ = ESC;
+                                       break;
+                               case 'c': case 'C':
+                                       *mp++ = ':';
+                                       break;
+                               default:
+                                       /*
+                                        * Catches '\', '^', and
+                                        *  everything else.
+                                        */
+                                       *mp++ = *(bp-1);
+                                       break;
+                       }
+               } else
+                       *mp++ = *bp++;
+               m_room--;
+
+               /*
+                * Enforce loop invariant: if no room left in current
+                * buffer, try to get some more.
+                */
+               if (m_room == 0) {
+                       size_t size = mp - mem;
+
+                       if ((mem = realloc(mem, size + SFRAG)) == NULL)
+                               return (-2);
+                       m_room = SFRAG;
+                       mp = mem + size;
+               }
+       }
+       *mp++ = '\0';   /* loop invariant let's us do this */
+       m_room--;
+       len = mp - mem - 1;
+
+       /*
+        * Give back any extra memory and return value and success.
+        */
+       if (m_room != 0)
+               if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL)
+                       return (-2);
+       *str = mem;
+       return (len);
+}
+
+/*
+ * Cgetustr retrieves the value of the string capability cap from the
+ * capability record pointed to by buf.  The difference between cgetustr()
+ * and cgetstr() is that cgetustr does not decode escapes but rather treats
+ * all characters literally.  A pointer to a  NUL terminated malloc'd 
+ * copy of the string is returned in the char pointed to by str.  The 
+ * length of the string not including the trailing NUL is returned on success,
+ * -1 if the requested string capability couldn't be found, -2 if a system 
+ * error was encountered (storage allocation failure).
+ */
+int
+cgetustr(buf, cap, str)
+       char *buf, *cap, **str;
+{
+       register u_int m_room;
+       register char *bp, *mp;
+       int len;
+       char *mem;
+
+       /*
+        * Find string capability cap
+        */
+       if ((bp = cgetcap(buf, cap, '=')) == NULL)
+               return (-1);
+
+       /*
+        * Conversion / storage allocation loop ...  Allocate memory in
+        * chunks SFRAG in size.
+        */
+       if ((mem = malloc(SFRAG)) == NULL) {
+               errno = ENOMEM;
+               return (-2);    /* couldn't even allocate the first fragment */
+       }
+       m_room = SFRAG;
+       mp = mem;
+
+       while (*bp != ':' && *bp != '\0') {
+               /*
+                * Loop invariants:
+                *      There is always room for one more character in mem.
+                *      Mp always points just past last character in mem.
+                *      Bp always points at next character in buf.
+                */
+               *mp++ = *bp++;
+               m_room--;
+
+               /*
+                * Enforce loop invariant: if no room left in current
+                * buffer, try to get some more.
+                */
+               if (m_room == 0) {
+                       size_t size = mp - mem;
+
+                       if ((mem = realloc(mem, size + SFRAG)) == NULL)
+                               return (-2);
+                       m_room = SFRAG;
+                       mp = mem + size;
+               }
+       }
+       *mp++ = '\0';   /* loop invariant let's us do this */
+       m_room--;
+       len = mp - mem - 1;
+
+       /*
+        * Give back any extra memory and return value and success.
+        */
+       if (m_room != 0)
+               if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL)
+                       return (-2);
+       *str = mem;
+       return (len);
+}
+
+/*
+ * Cgetnum retrieves the value of the numeric capability cap from the
+ * capability record pointed to by buf.  The numeric value is returned in
+ * the long pointed to by num.  0 is returned on success, -1 if the requested
+ * numeric capability couldn't be found.
+ */
+int
+cgetnum(buf, cap, num)
+       char *buf, *cap;
+       long *num;
+{
+       register long n;
+       register int base, digit;
+       register char *bp;
+
+       /*
+        * Find numeric capability cap
+        */
+       bp = cgetcap(buf, cap, '#');
+       if (bp == NULL)
+               return (-1);
+
+       /*
+        * Look at value and determine numeric base:
+        *      0x... or 0X...  hexadecimal,
+        * else 0...            octal,
+        * else                 decimal.
+        */
+       if (*bp == '0') {
+               bp++;
+               if (*bp == 'x' || *bp == 'X') {
+                       bp++;
+                       base = 16;
+               } else
+                       base = 8;
+       } else
+               base = 10;
+
+       /*
+        * Conversion loop ...
+        */
+       n = 0;
+       for (;;) {
+               if ('0' <= *bp && *bp <= '9')
+                       digit = *bp - '0';
+               else if ('a' <= *bp && *bp <= 'f')
+                       digit = 10 + *bp - 'a';
+               else if ('A' <= *bp && *bp <= 'F')
+                       digit = 10 + *bp - 'A';
+               else
+                       break;
+
+               if (digit >= base)
+                       break;
+
+               n = n * base + digit;
+               bp++;
+       }
+
+       /*
+        * Return value and success.
+        */
+       *num = n;
+       return (0);
+}
+
+
+/*
+ * Compare name field of record.
+ */
+static int
+nfcmp(nf, rec)
+       char *nf, *rec;
+{
+       char *cp, tmp;
+       int ret;
+       
+       for (cp = rec; *cp != ':'; cp++)
+               ;
+       
+       tmp = *(cp + 1);
+       *(cp + 1) = '\0';
+       ret = strcmp(nf, rec);
+       *(cp + 1) = tmp;
+
+       return (ret);
+}