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Annotation of embedaddon/sudo/compat/dlopen.c, revision 1.1.1.2

1.1       misho       1: /*
                      2:  * Copyright (c) 2010 Todd C. Miller <Todd.Miller@courtesan.com>
                      3:  *
                      4:  * Permission to use, copy, modify, and distribute this software for any
                      5:  * purpose with or without fee is hereby granted, provided that the above
                      6:  * copyright notice and this permission notice appear in all copies.
                      7:  *
                      8:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
                      9:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
                     10:  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
                     11:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
                     12:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
                     13:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
                     14:  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
                     15:  */
                     16: 
                     17: #include <config.h>
                     18: 
                     19: #include <sys/types.h>
                     20: 
                     21: #include <stdio.h>
                     22: #ifdef STDC_HEADERS
                     23: # include <stdlib.h>
                     24: # include <stddef.h>
                     25: #else
                     26: # ifdef HAVE_STDLIB_H
                     27: #  include <stdlib.h>
                     28: # endif
                     29: #endif /* STDC_HEADERS */
                     30: #ifdef HAVE_STRING_H
                     31: # include <string.h>
                     32: #endif /* HAVE_STRING_H */
                     33: #ifdef HAVE_STRINGS_H
                     34: # include <strings.h>
                     35: #endif /* HAVE_STRINGS_H */
                     36: #include <errno.h>
                     37: 
                     38: #include "compat/dlfcn.h"
                     39: #include "missing.h"
                     40: 
                     41: #ifdef HAVE_SHL_LOAD
                     42: /*
                     43:  * Emulate dlopen() using shl_load().
                     44:  */
                     45: #include <dl.h>
                     46: 
                     47: #ifndef DYNAMIC_PATH
                     48: # define DYNAMIC_PATH  0
                     49: #endif
                     50: 
                     51: void *
                     52: sudo_dlopen(const char *path, int mode)
                     53: {
                     54:     int flags = DYNAMIC_PATH;
                     55: 
                     56:     if (mode == 0)
                     57:        mode = RTLD_LAZY;       /* default behavior */
                     58: 
                     59:     /* We don't support RTLD_GLOBAL or RTLD_LOCAL yet. */
                     60:     if (ISSET(mode, RTLD_LAZY))
                     61:        flags |= BIND_DEFERRED;
                     62:     if (ISSET(mode, RTLD_NOW))
                     63:        flags |= BIND_IMMEDIATE;
                     64: 
                     65:     return (void *)shl_load(path, flags, 0L);
                     66: }
                     67: 
                     68: int
                     69: sudo_dlclose(void *handle)
                     70: {
                     71:     return shl_unload((shl_t)handle);
                     72: }
                     73: 
                     74: void *
                     75: sudo_dlsym(void *vhandle, const char *symbol)
                     76: {
                     77:     shl_t handle = vhandle;
                     78:     void *value = NULL;
                     79: 
1.1.1.2 ! misho      80:     /*
        !            81:      * Note that the behavior of of RTLD_NEXT and RTLD_SELF 
        !            82:      * differs from most implementations when called from
        !            83:      * a shared library.
        !            84:      */
        !            85:     if (vhandle == RTLD_NEXT) {
        !            86:        /* Iterate over all shared libs looking for symbol. */
        !            87:        struct shl_descriptor *desc;
        !            88:        int idx = 0;
        !            89:        while (shl_get(idx++, &desc) == 0) {
        !            90:            if (shl_findsym(&desc->handle, symbol, TYPE_UNDEFINED, &value) == 0)
        !            91:                break;
        !            92:        }
        !            93:     } else {
        !            94:        if (vhandle == RTLD_DEFAULT)
        !            95:            handle = NULL;
        !            96:        else if (vhandle == RTLD_SELF)
        !            97:            handle = PROG_HANDLE;
        !            98:        (void)shl_findsym(&handle, symbol, TYPE_UNDEFINED, &value);
        !            99:     }
1.1       misho     100: 
                    101:     return value;
                    102: }
                    103: 
                    104: char *
                    105: sudo_dlerror(void)
                    106: {
                    107:     return strerror(errno);
                    108: }
                    109: 
                    110: #else /* !HAVE_SHL_LOAD */
                    111: 
                    112: /*
                    113:  * Emulate dlopen() using a static list of symbols compiled into sudo.
                    114:  */
                    115: 
                    116: struct sudo_preload_table {
                    117:     const char *name;
                    118:     void *address;
                    119: };
                    120: extern struct sudo_preload_table sudo_preload_table[];
                    121: 
                    122: void *
                    123: sudo_dlopen(const char *path, int mode)
                    124: {
                    125:     return (void *)path;
                    126: }
                    127: 
                    128: int
                    129: sudo_dlclose(void *handle)
                    130: {
                    131:     return 0;
                    132: }
                    133: 
                    134: void *
                    135: sudo_dlsym(void *handle, const char *symbol)
                    136: {
                    137:     struct sudo_preload_table *sym;
                    138: 
1.1.1.2 ! misho     139:     if (symbol != RTLD_NEXT && symbol != RTLD_DEFAULT && symbol != RTLD_SELF) {
        !           140:        for (sym = sudo_preload_table; sym->name != NULL; sym++) {
        !           141:            if (strcmp(symbol, sym->name) == 0)
        !           142:                return sym->address;
        !           143:        }
1.1       misho     144:     }
                    145:     return NULL;
                    146: }
                    147: 
                    148: char *
                    149: sudo_dlerror(void)
                    150: {
                    151:     return strerror(errno);
                    152: }
                    153: 
                    154: #endif /* HAVE_SHL_LOAD */