FreeBSD/Linux Kernel Cross Reference
sys/boot/common/module.c

     /*-
      * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
      * All rights reserved.
      *
      * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    /*
     * file/module function dispatcher, support, etc.
     */
    
    #include <stand.h>
    #include <string.h>
    #include <sys/param.h>
    #include <sys/linker.h>
    #include <sys/module.h>
    #include <sys/queue.h>
    
    #include "bootstrap.h"
    
    #define MDIR_REMOVED    0x0001
    #define MDIR_NOHINTS    0x0002
    
    struct moduledir {
            char    *d_path;        /* path of modules directory */
            u_char  *d_hints;       /* content of linker.hints file */
            int     d_hintsz;       /* size of hints data */
            int     d_flags;
            STAILQ_ENTRY(moduledir) d_link;
    };
    
    static int                      file_load(char *filename, vm_offset_t dest, struct preloaded_file **result);
    static int                      file_loadraw(char *type, char *name);
    static int                      file_load_dependencies(struct preloaded_file *base_mod);
    static char *                   file_search(const char *name, char **extlist);
    static struct kernel_module *   file_findmodule(struct preloaded_file *fp, char *modname, struct mod_depend *verinfo);
    static int                      file_havepath(const char *name);
    static char                     *mod_searchmodule(char *name, struct mod_depend *verinfo);
    static void                     file_insert_tail(struct preloaded_file *mp);
    struct file_metadata*           metadata_next(struct file_metadata *base_mp, int type);
    static void                     moduledir_readhints(struct moduledir *mdp);
    static void                     moduledir_rebuild(void);
    
    /* load address should be tweaked by first module loaded (kernel) */
    static vm_offset_t      loadaddr = 0;
    
    static const char       *default_searchpath ="/boot/kernel;/boot/modules";
    
    static STAILQ_HEAD(, moduledir) moduledir_list = STAILQ_HEAD_INITIALIZER(moduledir_list);
    
    struct preloaded_file *preloaded_files = NULL;
    
    static char *kld_ext_list[] = {
        ".ko",
        "",
        ".debug",
        NULL
    };
    
    
    /*
     * load an object, either a disk file or code module.
     *
     * To load a file, the syntax is:
     *
     * load -t <type> <path>
     *
     * code modules are loaded as:
     *
     * load <path> <options>
     */
    
    COMMAND_SET(load, "load", "load a kernel or module", command_load);
    
    static int
    command_load(int argc, char *argv[])
    {
       char        *typestr;
       int         dofile, dokld, ch, error;
       
       dokld = dofile = 0;
       optind = 1;
       optreset = 1;
       typestr = NULL;
       if (argc == 1) {
           command_errmsg = "no filename specified";
           return(CMD_ERROR);
       }
       while ((ch = getopt(argc, argv, "kt:")) != -1) {
           switch(ch) {
           case 'k':
               dokld = 1;
               break;
           case 't':
               typestr = optarg;
               dofile = 1;
               break;
           case '?':
           default:
               /* getopt has already reported an error */
               return(CMD_OK);
           }
       }
       argv += (optind - 1);
       argc -= (optind - 1);
   
       /*
        * Request to load a raw file?
        */
       if (dofile) {
           if ((argc != 2) || (typestr == NULL) || (*typestr == 0)) {
               command_errmsg = "invalid load type";
               return(CMD_ERROR);
           }
           return(file_loadraw(typestr, argv[1]));
       }
       /*
        * Do we have explicit KLD load ?
        */
       if (dokld || file_havepath(argv[1])) {
           error = mod_loadkld(argv[1], argc - 2, argv + 2);
           if (error == EEXIST)
               sprintf(command_errbuf, "warning: KLD '%s' already loaded", argv[1]);
           return (error == 0 ? CMD_OK : CMD_ERROR);
       }
       /*
        * Looks like a request for a module.
        */
       error = mod_load(argv[1], NULL, argc - 2, argv + 2);
       if (error == EEXIST)
           sprintf(command_errbuf, "warning: module '%s' already loaded", argv[1]);
       return (error == 0 ? CMD_OK : CMD_ERROR);
   }
   
   COMMAND_SET(unload, "unload", "unload all modules", command_unload);
   
   static int
   command_unload(int argc, char *argv[])
   {
       struct preloaded_file       *fp;
       
       while (preloaded_files != NULL) {
           fp = preloaded_files;
           preloaded_files = preloaded_files->f_next;
           file_discard(fp);
       }
       loadaddr = 0;
       unsetenv("kernelname");
       return(CMD_OK);
   }
   
   COMMAND_SET(lsmod, "lsmod", "list loaded modules", command_lsmod);
   
   static int
   command_lsmod(int argc, char *argv[])
   {
       struct preloaded_file       *fp;
       struct kernel_module        *mp;
       struct file_metadata        *md;
       char                        lbuf[80];
       int                         ch, verbose;
   
       verbose = 0;
       optind = 1;
       optreset = 1;
       while ((ch = getopt(argc, argv, "v")) != -1) {
           switch(ch) {
           case 'v':
               verbose = 1;
               break;
           case '?':
           default:
               /* getopt has already reported an error */
               return(CMD_OK);
           }
       }
   
       pager_open();
       for (fp = preloaded_files; fp; fp = fp->f_next) {
           sprintf(lbuf, " %p: %s (%s, 0x%lx)\n", 
                   (void *) fp->f_addr, fp->f_name, fp->f_type, (long) fp->f_size);
           pager_output(lbuf);
           if (fp->f_args != NULL) {
               pager_output("    args: ");
               pager_output(fp->f_args);
               pager_output("\n");
           }
           if (fp->f_modules) {
               pager_output("  modules: ");
               for (mp = fp->f_modules; mp; mp = mp->m_next) {
                   sprintf(lbuf, "%s.%d ", mp->m_name, mp->m_version);
                   pager_output(lbuf);
               }
               pager_output("\n");
           }
           if (verbose) {
               /* XXX could add some formatting smarts here to display some better */
               for (md = fp->f_metadata; md != NULL; md = md->md_next) {
                   sprintf(lbuf, "      0x%04x, 0x%lx\n", md->md_type, (long) md->md_size);
                   pager_output(lbuf);
               }
           }
       }
       pager_close();
       return(CMD_OK);
   }
   
   /*
    * File level interface, functions file_*
    */
   int
   file_load(char *filename, vm_offset_t dest, struct preloaded_file **result)
   {
       struct preloaded_file *fp;
       int error;
       int i;
   
       error = EFTYPE;
       for (i = 0, fp = NULL; file_formats[i] && fp == NULL; i++) {
           error = (file_formats[i]->l_load)(filename, loadaddr, &fp);
           if (error == 0) {
               fp->f_loader = i;           /* remember the loader */
               *result = fp;
               break;
           }
           if (error == EFTYPE)
               continue;           /* Unknown to this handler? */
           if (error) {
               sprintf(command_errbuf, "can't load file '%s': %s",
                   filename, strerror(error));
               break;
           }
       }
       return (error);
   }
   
   static int
   file_load_dependencies(struct preloaded_file *base_file) {
       struct file_metadata *md;
       struct preloaded_file *fp;
       struct mod_depend *verinfo;
       struct kernel_module *mp;
       char *dmodname;
       int error;
   
       md = file_findmetadata(base_file, MODINFOMD_DEPLIST);
       if (md == NULL)
           return (0);
       error = 0;
       do {
           verinfo = (struct mod_depend*)md->md_data;
           dmodname = (char *)(verinfo + 1);
           if (file_findmodule(NULL, dmodname, verinfo) == NULL) {
               printf("loading required module '%s'\n", dmodname);
               error = mod_load(dmodname, verinfo, 0, NULL);
               if (error)
                   break;
               /*
                * If module loaded via kld name which isn't listed
                * in the linker.hints file, we should check if it have
                * required version.
                */
               mp = file_findmodule(NULL, dmodname, verinfo);
               if (mp == NULL) {
                   sprintf(command_errbuf, "module '%s' exists but with wrong version",
                       dmodname);
                   error = ENOENT;
                   break;
               }
           }
           md = metadata_next(md, MODINFOMD_DEPLIST);
       } while (md);
       if (!error)
           return (0);
       /* Load failed; discard everything */
       while (base_file != NULL) {
           fp = base_file;
           base_file = base_file->f_next;
           file_discard(fp);
       }
       return (error);
   }
   /*
    * We've been asked to load (name) as (type), so just suck it in,
    * no arguments or anything.
    */
   int
   file_loadraw(char *type, char *name)
   {
       struct preloaded_file       *fp;
       char                        *cp;
       int                         fd, got;
       vm_offset_t                 laddr;
   
       /* We can't load first */
       if ((file_findfile(NULL, NULL)) == NULL) {
           command_errmsg = "can't load file before kernel";
           return(CMD_ERROR);
       }
   
       /* locate the file on the load path */
       cp = file_search(name, NULL);
       if (cp == NULL) {
           sprintf(command_errbuf, "can't find '%s'", name);
           return(CMD_ERROR);
       }
       name = cp;
       
       if ((fd = open(name, O_RDONLY)) < 0) {
           sprintf(command_errbuf, "can't open '%s': %s", name, strerror(errno));
           free(name);
           return(CMD_ERROR);
       }
   
       laddr = loadaddr;
       for (;;) {
           /* read in 4k chunks; size is not really important */
           got = archsw.arch_readin(fd, laddr, 4096);
           if (got == 0)                           /* end of file */
               break;
           if (got < 0) {                          /* error */
               sprintf(command_errbuf, "error reading '%s': %s", name, strerror(errno));
               free(name);
               close(fd);
               return(CMD_ERROR);
           }
           laddr += got;
       }
       
       /* Looks OK so far; create & populate control structure */
       fp = file_alloc();
       fp->f_name = name;
       fp->f_type = strdup(type);
       fp->f_args = NULL;
       fp->f_metadata = NULL;
       fp->f_loader = -1;
       fp->f_addr = loadaddr;
       fp->f_size = laddr - loadaddr;
   
       /* recognise space consumption */
       loadaddr = laddr;
   
       /* Add to the list of loaded files */
       file_insert_tail(fp);
       close(fd);
       return(CMD_OK);
   }
   
   /*
    * Load the module (name), pass it (argc),(argv), add container file
    * to the list of loaded files.
    * If module is already loaded just assign new argc/argv.
    */
   int
   mod_load(char *modname, struct mod_depend *verinfo, int argc, char *argv[])
   {
       struct kernel_module        *mp;
       int                         err;
       char                        *filename;
   
       if (file_havepath(modname)) {
           printf("Warning: mod_load() called instead of mod_loadkld() for module '%s'\n", modname);
           return (mod_loadkld(modname, argc, argv));
       }
       /* see if module is already loaded */
       mp = file_findmodule(NULL, modname, verinfo);
       if (mp) {
   #ifdef moduleargs
           if (mp->m_args)
               free(mp->m_args);
           mp->m_args = unargv(argc, argv);
   #endif
           sprintf(command_errbuf, "warning: module '%s' already loaded", mp->m_name);
           return (0);
       }
       /* locate file with the module on the search path */
       filename = mod_searchmodule(modname, verinfo);
       if (filename == NULL) {
           sprintf(command_errbuf, "can't find '%s'", modname);
           return (ENOENT);
       }
       err = mod_loadkld(filename, argc, argv);
       return (err);
   }
   
   /*
    * Load specified KLD. If path is omitted, then try to locate it via
    * search path.
    */
   int
   mod_loadkld(const char *kldname, int argc, char *argv[])
   {
       struct preloaded_file       *fp, *last_file;
       int                         err;
       char                        *filename;
   
       /*
        * Get fully qualified KLD name
        */
       filename = file_search(kldname, kld_ext_list);
       if (filename == NULL) {
           sprintf(command_errbuf, "can't find '%s'", kldname);
           return (ENOENT);
       }
       /* 
        * Check if KLD already loaded
        */
       fp = file_findfile(filename, NULL);
       if (fp) {
           sprintf(command_errbuf, "warning: KLD '%s' already loaded", filename);
           free(filename);
           return (0);
       }
       for (last_file = preloaded_files; 
            last_file != NULL && last_file->f_next != NULL;
            last_file = last_file->f_next)
           ;
   
       do {
           err = file_load(filename, loadaddr, &fp);
           if (err)
               break;
           fp->f_args = unargv(argc, argv);
           loadaddr = fp->f_addr + fp->f_size;
           file_insert_tail(fp);           /* Add to the list of loaded files */
           if (file_load_dependencies(fp) != 0) {
               err = ENOENT;
               last_file->f_next = NULL;
               loadaddr = last_file->f_addr + last_file->f_size;
               fp = NULL;
               break;
           }
       } while(0);
       if (err == EFTYPE)
           sprintf(command_errbuf, "don't know how to load module '%s'", filename);
       if (err && fp)
           file_discard(fp);
       free(filename);
       return (err);
   }
   
   /*
    * Find a file matching (name) and (type).
    * NULL may be passed as a wildcard to either.
    */
   struct preloaded_file *
   file_findfile(char *name, char *type)
   {
       struct preloaded_file *fp;
   
       for (fp = preloaded_files; fp != NULL; fp = fp->f_next) {
           if (((name == NULL) || !strcmp(name, fp->f_name)) &&
               ((type == NULL) || !strcmp(type, fp->f_type)))
               break;
       }
       return (fp);
   }
   
   /*
    * Find a module matching (name) inside of given file.
    * NULL may be passed as a wildcard.
    */
   struct kernel_module *
   file_findmodule(struct preloaded_file *fp, char *modname,
           struct mod_depend *verinfo)
   {
       struct kernel_module *mp, *best;
       int bestver, mver;
   
       if (fp == NULL) {
           for (fp = preloaded_files; fp; fp = fp->f_next) {
               mp = file_findmodule(fp, modname, verinfo);
               if (mp)
                   return (mp);
           }
           return (NULL);
       }
       best = NULL;
       bestver = 0;
       for (mp = fp->f_modules; mp; mp = mp->m_next) {
           if (strcmp(modname, mp->m_name) == 0) {
               if (verinfo == NULL)
                   return (mp);
               mver = mp->m_version;
               if (mver == verinfo->md_ver_preferred)
                   return (mp);
               if (mver >= verinfo->md_ver_minimum && 
                   mver <= verinfo->md_ver_maximum &&
                   mver > bestver) {
                   best = mp;
                   bestver = mver;
               }
           }
       }
       return (best);
   }
   /*
    * Make a copy of (size) bytes of data from (p), and associate them as
    * metadata of (type) to the module (mp).
    */
   void
   file_addmetadata(struct preloaded_file *fp, int type, size_t size, void *p)
   {
       struct file_metadata        *md;
   
       md = malloc(sizeof(struct file_metadata) - sizeof(md->md_data) + size);
       md->md_size = size;
       md->md_type = type;
       bcopy(p, md->md_data, size);
       md->md_next = fp->f_metadata;
       fp->f_metadata = md;
   }
   
   /*
    * Find a metadata object of (type) associated with the file (fp)
    */
   struct file_metadata *
   file_findmetadata(struct preloaded_file *fp, int type)
   {
       struct file_metadata *md;
   
       for (md = fp->f_metadata; md != NULL; md = md->md_next)
           if (md->md_type == type)
               break;
       return(md);
   }
   
   struct file_metadata *
   metadata_next(struct file_metadata *md, int type)
   {
       if (md == NULL)
           return (NULL);
       while((md = md->md_next) != NULL)
           if (md->md_type == type)
               break;
       return (md);
   }
   
   static char *emptyextlist[] = { "", NULL };
   
   /*
    * Check if the given file is in place and return full path to it.
    */
   static char *
   file_lookup(const char *path, const char *name, int namelen, char **extlist)
   {
       struct stat st;
       char        *result, *cp, **cpp;
       int         pathlen, extlen, len;
   
       pathlen = strlen(path);
       extlen = 0;
       if (extlist == NULL)
           extlist = emptyextlist;
       for (cpp = extlist; *cpp; cpp++) {
           len = strlen(*cpp);
           if (len > extlen)
               extlen = len;
       }
       result = malloc(pathlen + namelen + extlen + 2);
       if (result == NULL)
           return (NULL);
       bcopy(path, result, pathlen);
       if (pathlen > 0 && result[pathlen - 1] != '/')
           result[pathlen++] = '/';
       cp = result + pathlen;
       bcopy(name, cp, namelen);
       cp += namelen;
       for (cpp = extlist; *cpp; cpp++) {
           strcpy(cp, *cpp);
           if (stat(result, &st) == 0 && S_ISREG(st.st_mode))
               return result;
       }
       free(result);
       return NULL;
   }
   
   /*
    * Check if file name have any qualifiers
    */
   static int
   file_havepath(const char *name)
   {
       const char          *cp;
   
       archsw.arch_getdev(NULL, name, &cp);
       return (cp != name || strchr(name, '/') != NULL);
   }
   
   /*
    * Attempt to find the file (name) on the module searchpath.
    * If (name) is qualified in any way, we simply check it and
    * return it or NULL.  If it is not qualified, then we attempt
    * to construct a path using entries in the environment variable
    * module_path.
    *
    * The path we return a pointer to need never be freed, as we manage
    * it internally.
    */
   static char *
   file_search(const char *name, char **extlist)
   {
       struct moduledir    *mdp;
       struct stat         sb;
       char                *result;
       int                 namelen;
   
       /* Don't look for nothing */
       if (name == NULL)
           return(NULL);
   
       if (*name == 0)
           return(strdup(name));
   
       if (file_havepath(name)) {
           /* Qualified, so just see if it exists */
           if (stat(name, &sb) == 0)
               return(strdup(name));
           return(NULL);
       }
       moduledir_rebuild();
       result = NULL;
       namelen = strlen(name);
       STAILQ_FOREACH(mdp, &moduledir_list, d_link) {
           result = file_lookup(mdp->d_path, name, namelen, extlist);
           if (result)
               break;
       }
       return(result);
   }
   
   #define INT_ALIGN(base, ptr)    ptr = \
           (base) + (((ptr) - (base) + sizeof(int) - 1) & ~(sizeof(int) - 1))
   
   static char *
   mod_search_hints(struct moduledir *mdp, const char *modname,
           struct mod_depend *verinfo)
   {
       u_char      *cp, *recptr, *bufend, *best;
       char        *result;
       int         *intp, bestver, blen, clen, found, ival, modnamelen, reclen;
   
       moduledir_readhints(mdp);
       modnamelen = strlen(modname);
       found = 0;
       result = NULL;
       bestver = 0;
       if (mdp->d_hints == NULL)
           goto bad;
       recptr = mdp->d_hints;
       bufend = recptr + mdp->d_hintsz;
       clen = blen = 0;
       best = cp = NULL;
       while (recptr < bufend && !found) {
           intp = (int*)recptr;
           reclen = *intp++;
           ival = *intp++;
           cp = (char*)intp;
           switch (ival) {
           case MDT_VERSION:
               clen = *cp++;
               if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
                   break;
               cp += clen;
               INT_ALIGN(mdp->d_hints, cp);
               ival = *(int*)cp;
               cp += sizeof(int);
               clen = *cp++;
               if (verinfo == NULL || ival == verinfo->md_ver_preferred) {
                   found = 1;
                   break;
               }
               if (ival >= verinfo->md_ver_minimum && 
                   ival <= verinfo->md_ver_maximum &&
                   ival > bestver) {
                   bestver = ival;
                   best = cp;
                   blen = clen;
               }
               break;
           default:
               break;
           }
           recptr += reclen + sizeof(int);
       }
       /*
        * Finally check if KLD is in the place
        */
       if (found)
           result = file_lookup(mdp->d_path, cp, clen, NULL);
       else if (best)
           result = file_lookup(mdp->d_path, best, blen, NULL);
   bad:
       /*
        * If nothing found or hints is absent - fallback to the old way
        * by using "kldname[.ko]" as module name.
        */
       if (!found && !bestver && result == NULL)
           result = file_lookup(mdp->d_path, modname, modnamelen, kld_ext_list);
       return result;
   }
   
   /*
    * Attempt to locate the file containing the module (name)
    */
   static char *
   mod_searchmodule(char *name, struct mod_depend *verinfo)
   {
       struct      moduledir *mdp;
       char        *result;
   
       moduledir_rebuild();
       /*
        * Now we ready to lookup module in the given directories
        */
       result = NULL;
       STAILQ_FOREACH(mdp, &moduledir_list, d_link) {
           result = mod_search_hints(mdp, name, verinfo);
           if (result)
               break;
       }
   
       return(result);
   }
   
   int
   file_addmodule(struct preloaded_file *fp, char *modname, int version,
           struct kernel_module **newmp)
   {
       struct kernel_module *mp;
       struct mod_depend mdepend;
   
       bzero(&mdepend, sizeof(mdepend));
       mdepend.md_ver_preferred = version;
       mp = file_findmodule(fp, modname, &mdepend);
       if (mp)
           return (EEXIST);
       mp = malloc(sizeof(struct kernel_module));
       if (mp == NULL)
           return (ENOMEM);
       bzero(mp, sizeof(struct kernel_module));
       mp->m_name = strdup(modname);
       mp->m_version = version;
       mp->m_fp = fp;
       mp->m_next = fp->f_modules;
       fp->f_modules = mp;
       if (newmp)
           *newmp = mp;
       return (0);
   }
   
   /*
    * Throw a file away
    */
   void
   file_discard(struct preloaded_file *fp)
   {
       struct file_metadata        *md, *md1;
       struct kernel_module        *mp, *mp1;
       if (fp == NULL)
           return;
       md = fp->f_metadata;
       while (md) {
           md1 = md;
           md = md->md_next;
           free(md1);
       }
       mp = fp->f_modules;
       while (mp) {
           if (mp->m_name)
               free(mp->m_name);
           mp1 = mp;
           mp = mp->m_next;
           free(mp1);
       }   
       if (fp->f_name != NULL)
           free(fp->f_name);
       if (fp->f_type != NULL)
           free(fp->f_type);
       if (fp->f_args != NULL)
           free(fp->f_args);
       free(fp);
   }
   
   /*
    * Allocate a new file; must be used instead of malloc()
    * to ensure safe initialisation.
    */
   struct preloaded_file *
   file_alloc(void)
   {
       struct preloaded_file       *fp;
       
       if ((fp = malloc(sizeof(struct preloaded_file))) != NULL) {
           bzero(fp, sizeof(struct preloaded_file));
       }
       return (fp);
   }
   
   /*
    * Add a module to the chain
    */
   static void
   file_insert_tail(struct preloaded_file *fp)
   {
       struct preloaded_file       *cm;
       
       /* Append to list of loaded file */
       fp->f_next = NULL;
       if (preloaded_files == NULL) {
           preloaded_files = fp;
       } else {
           for (cm = preloaded_files; cm->f_next != NULL; cm = cm->f_next)
               ;
           cm->f_next = fp;
       }
   }
   
   static char *
   moduledir_fullpath(struct moduledir *mdp, const char *fname)
   {
       char *cp;
   
       cp = malloc(strlen(mdp->d_path) + strlen(fname) + 2);
       if (cp == NULL)
           return NULL;
       strcpy(cp, mdp->d_path);
       strcat(cp, "/");
       strcat(cp, fname);
       return (cp);
   }
   
   /*
    * Read linker.hints file into memory performing some sanity checks.
    */
   static void
   moduledir_readhints(struct moduledir *mdp)
   {
       struct stat st;
       char        *path;
       int         fd, size, version;
   
       if (mdp->d_hints != NULL || (mdp->d_flags & MDIR_NOHINTS))
           return;
       path = moduledir_fullpath(mdp, "linker.hints");
       if (stat(path, &st) != 0 ||
           st.st_size < (ssize_t)(sizeof(version) + sizeof(int)) ||
           st.st_size > 100 * 1024 || (fd = open(path, O_RDONLY)) < 0) {
           free(path);
           mdp->d_flags |= MDIR_NOHINTS;
           return;
       }
       free(path);
       size = read(fd, &version, sizeof(version));
       if (size != sizeof(version) || version != LINKER_HINTS_VERSION)
           goto bad;
       size = st.st_size - size;
       mdp->d_hints = malloc(size);
       if (mdp->d_hints == NULL)
           goto bad;
       if (read(fd, mdp->d_hints, size) != size)
           goto bad;
       mdp->d_hintsz = size;
       close(fd);
       return;
   bad:
       close(fd);
       if (mdp->d_hints) {
           free(mdp->d_hints);
           mdp->d_hints = NULL;
       }
       mdp->d_flags |= MDIR_NOHINTS;
       return;
   }
   
   /*
    * Extract directories from the ';' separated list, remove duplicates.
    */
   static void
   moduledir_rebuild(void)
   {
       struct      moduledir *mdp, *mtmp;
       const char  *path, *cp, *ep;
       int         cplen;
   
       path = getenv("module_path");
       if (path == NULL)
           path = default_searchpath;
       /*
        * Rebuild list of module directories if it changed
        */
       STAILQ_FOREACH(mdp, &moduledir_list, d_link)
           mdp->d_flags |= MDIR_REMOVED;
   
       for (ep = path; *ep != 0;  ep++) {
           cp = ep;
           for (; *ep != 0 && *ep != ';'; ep++)
               ;
           /*
            * Ignore trailing slashes
            */
           for (cplen = ep - cp; cplen > 1 && cp[cplen - 1] == '/'; cplen--)
               ;
           STAILQ_FOREACH(mdp, &moduledir_list, d_link) {
               if (strlen(mdp->d_path) != cplen || bcmp(cp, mdp->d_path, cplen) != 0)
                   continue;
               mdp->d_flags &= ~MDIR_REMOVED;
               break;
           }
           if (mdp == NULL) {
               mdp = malloc(sizeof(*mdp) + cplen + 1);
               if (mdp == NULL)
                   return;
               mdp->d_path = (char*)(mdp + 1);
               bcopy(cp, mdp->d_path, cplen);
               mdp->d_path[cplen] = 0;
               mdp->d_hints = NULL;
               mdp->d_flags = 0;
               STAILQ_INSERT_TAIL(&moduledir_list, mdp, d_link);
           }
           if (*ep == 0)
               break;
       }
       /*
        * Delete unused directories if any
        */
       mdp = STAILQ_FIRST(&moduledir_list);
       while (mdp) {
           if ((mdp->d_flags & MDIR_REMOVED) == 0) {
               mdp = STAILQ_NEXT(mdp, d_link);
           } else {
               if (mdp->d_hints)
                   free(mdp->d_hints);
               mtmp = mdp;
               mdp = STAILQ_NEXT(mdp, d_link);
               STAILQ_REMOVE(&moduledir_list, mtmp, moduledir, d_link);
               free(mtmp);
           }
       }
       return;
   }

Cache object: 46cc3ebbfed547226e1a2acc87f26598