libc-bottom-half/libpreopen/lib/internal.h

   1 /**
   2  * @file   internal.h
   3  * @brief  Declarations of internal data structures and functions
   4  *
   5  * @cond internal
   6  */
   7
   8 /*-
   9  * Copyright (c) 2016-2017 Stanley Uche Godfrey
  10  * Copyright (c) 2016-2018 Jonathan Anderson
  11  * All rights reserved.
  12  *
  13  * This software was developed at Memorial University under the
  14  * NSERC Discovery program (RGPIN-2015-06048).
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  */
  37
  38 #ifndef LIBPO_INTERNAL_H
  39 #define LIBPO_INTERNAL_H
  40
  41 #ifdef __wasilibc_unmodified_upstream
  42 #include <sys/cdefs.h>
  43 #endif
  44
  45 #ifdef __wasilibc_unmodified_upstream
  46 #ifdef WITH_CAPSICUM
  47 #include <sys/capsicum.h>
  48 #endif
  49 #else
  50 // We do Capsicum-style rights-checking, though we use the WASI API directly
  51 // rather than the Capsicum API.
  52 #define WITH_CAPSICUM
  53 #endif
  54
  55 #include <assert.h>
  56 #include <stdbool.h>
  57
  58 #include "libpreopen.h"
  59
  60 /**
  61  * An entry in a po_map.
  62  *
  63  * @internal
  64  */
  65 struct po_map_entry {
  66         /**
  67          * The name this file or directory is mapped to.
  68          *
  69          * This name should look like a path, but it does not necessarily need
  70          * match to match the path it was originally obtained from.
  71          */
  72         const char *name;
  73
  74         /** File descriptor (which may be a directory) */
  75         int fd;
  76
  77 #ifdef WITH_CAPSICUM
  78         /** Capability rights associated with the file descriptor */
  79 #ifdef __wasilibc_unmodified_upstream
  80         cap_rights_t rights;
  81 #else
  82         __wasi_rights_t rights_base;
  83         __wasi_rights_t rights_inheriting;
  84 #endif
  85 #endif
  86 };
  87
  88 // Documented in external header file
  89 struct po_map {
  90         //! @internal
  91         int refcount;
  92         struct po_map_entry *entries;
  93         size_t capacity;
  94         size_t length;
  95 };
  96
  97
  98 /**
  99  * Is a directory a prefix of a given path?
 100  *
 101  * @param   dir     a directory path, e.g., `/foo/bar`
 102  * @param   dirlen  the length of @b dir
 103  * @param   path    a path that may have @b dir as a prefix,
 104  *                  e.g., `/foo/bar/baz`
 105  *
 106  * @internal
 107  */
 108 #ifdef __wasilibc_unmodified_upstream
 109 #else
 110 static
 111 #endif
 112 bool    po_isprefix(const char *dir, size_t dirlen, const char *path);
 113
 114
 115 /**
 116  * Check that a @ref po_map is valid (assert out if it's not).
 117  *
 118  * @internal
 119  */
 120 #ifdef NDEBUG
 121 #define po_map_assertvalid(...)
 122 #else
 123 #ifdef __wasilibc_unmodified_upstream
 124 #else
 125 static
 126 #endif
 127 void    po_map_assertvalid(const struct po_map *);
 128 #endif
 129
 130 /**
 131  * Enlarge a @ref po_map's capacity.
 132  *
 133  * This results in new memory being allocated and existing entries being copied.
 134  * If the allocation fails, the function will return NULL but the original
 135  * map will remain valid.
 136  *
 137  * @internal
 138  */
 139 #ifdef __wasilibc_unmodified_upstream
 140 #else
 141 static
 142 #endif
 143 struct po_map* po_map_enlarge(struct po_map *map);
 144
 145 #ifdef __wasilibc_unmodified_upstream
 146 /**
 147  * Store an error message in the global "last error message" buffer.
 148  *
 149  * @internal
 150  */
 151 void po_errormessage(const char *msg);
 152 #endif
 153
 154 /**
 155  * Set the default map used by the libpreopen libc wrappers.
 156  *
 157  * If there is an existing default map, it will be freed before it is replaced.
 158  * Passing NULL to this function will thus clear the default map.
 159  */
 160 #ifdef __wasilibc_unmodified_upstream
 161 void po_set_libc_map(struct po_map *);
 162 #endif
 163
 164 #endif /* LIBPO_INTERNAL_H */
 165
 166 /** @endcond */