uci_internal.h

   1 /*
   2  * libuci - Library for the Unified Configuration Interface
   3  * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU Lesser General Public License version 2.1
   7  * as published by the Free Software Foundation
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU Lesser General Public License for more details.
  13  */
  14
  15 #ifndef __UCI_INTERNAL_H
  16 #define __UCI_INTERNAL_H
  17
  18 #define __private __attribute__((visibility("hidden")))
  19 #define __public
  20
  21 struct uci_parse_context
  22 {
  23         /* error context */
  24         const char *reason;
  25         int line;
  26         int byte;
  27
  28         /* private: */
  29         struct uci_package *package;
  30         struct uci_section *section;
  31         bool merge;
  32         FILE *file;
  33         const char *name;
  34         char *buf;
  35         int bufsz;
  36 };
  37
  38 extern const char *uci_confdir;
  39 extern const char *uci_savedir;
  40
  41 __private void *uci_malloc(struct uci_context *ctx, size_t size);
  42 __private void *uci_realloc(struct uci_context *ctx, void *ptr, size_t size);
  43 __private char *uci_strdup(struct uci_context *ctx, const char *str);
  44 __private bool uci_validate_str(const char *str, bool name);
  45 __private void uci_add_delta(struct uci_context *ctx, struct uci_list *list, int cmd, const char *section, const char *option, const char *value);
  46 __private void uci_free_delta(struct uci_delta *h);
  47 __private struct uci_package *uci_alloc_package(struct uci_context *ctx, const char *name);
  48
  49 __private FILE *uci_open_stream(struct uci_context *ctx, const char *filename, int pos, bool write, bool create);
  50 __private void uci_close_stream(FILE *stream);
  51 __private void uci_getln(struct uci_context *ctx, int offset);
  52
  53 __private void uci_parse_error(struct uci_context *ctx, char *pos, char *reason);
  54 __private void uci_alloc_parse_context(struct uci_context *ctx);
  55
  56 __private void uci_cleanup(struct uci_context *ctx);
  57 __private struct uci_element *uci_lookup_list(struct uci_list *list, const char *name);
  58 __private void uci_fixup_section(struct uci_context *ctx, struct uci_section *s);
  59 __private void uci_free_package(struct uci_package **package);
  60 __private struct uci_element *uci_alloc_generic(struct uci_context *ctx, int type, const char *name, int size);
  61 __private void uci_free_element(struct uci_element *e);
  62 __private struct uci_element *uci_expand_ptr(struct uci_context *ctx, struct uci_ptr *ptr, bool complete);
  63
  64 __private int uci_load_delta(struct uci_context *ctx, struct uci_package *p, bool flush);
  65
  66 static inline bool uci_validate_package(const char *str)
  67 {
  68         return uci_validate_str(str, false);
  69 }
  70
  71 static inline bool uci_validate_type(const char *str)
  72 {
  73         return uci_validate_str(str, false);
  74 }
  75
  76 static inline bool uci_validate_name(const char *str)
  77 {
  78         return uci_validate_str(str, true);
  79 }
  80
  81 /* initialize a list head/item */
  82 static inline void uci_list_init(struct uci_list *ptr)
  83 {
  84         ptr->prev = ptr;
  85         ptr->next = ptr;
  86 }
  87
  88 /* inserts a new list entry after a given entry */
  89 static inline void uci_list_insert(struct uci_list *list, struct uci_list *ptr)
  90 {
  91         list->next->prev = ptr;
  92         ptr->prev = list;
  93         ptr->next = list->next;
  94         list->next = ptr;
  95 }
  96
  97 /* inserts a new list entry at the tail of the list */
  98 static inline void uci_list_add(struct uci_list *head, struct uci_list *ptr)
  99 {
 100         /* NB: head->prev points at the tail */
 101         uci_list_insert(head->prev, ptr);
 102 }
 103
 104 static inline void uci_list_del(struct uci_list *ptr)
 105 {
 106         struct uci_list *next, *prev;
 107
 108         next = ptr->next;
 109         prev = ptr->prev;
 110
 111         prev->next = next;
 112         next->prev = prev;
 113
 114         uci_list_init(ptr);
 115 }
 116
 117
 118 extern struct uci_backend uci_file_backend;
 119
 120 #ifdef UCI_PLUGIN_SUPPORT
 121 /**
 122  * uci_add_backend: add an extra backend
 123  * @ctx: uci context
 124  * @name: name of the backend
 125  *
 126  * The default backend is "file", which uses /etc/config for config storage
 127  */
 128 __private int uci_add_backend(struct uci_context *ctx, struct uci_backend *b);
 129
 130 /**
 131  * uci_add_backend: add an extra backend
 132  * @ctx: uci context
 133  * @name: name of the backend
 134  *
 135  * The default backend is "file", which uses /etc/config for config storage
 136  */
 137 __private int uci_del_backend(struct uci_context *ctx, struct uci_backend *b);
 138 #endif
 139
 140 #define UCI_BACKEND(_var, _name, ...)   \
 141 struct uci_backend _var = {             \
 142         .e.list = {                     \
 143                 .next = &_var.e.list,   \
 144                 .prev = &_var.e.list,   \
 145         },                              \
 146         .e.name = _name,                \
 147         .e.type = UCI_TYPE_BACKEND,     \
 148         .ptr = &_var,                   \
 149         __VA_ARGS__                     \
 150 }
 151
 152
 153 /*
 154  * functions for debug and error handling, for internal use only
 155  */
 156
 157 #ifdef UCI_DEBUG
 158 #define DPRINTF(...) fprintf(stderr, __VA_ARGS__)
 159 #else
 160 #define DPRINTF(...)
 161 #endif
 162
 163 /*
 164  * throw an uci exception and store the error number
 165  * in the context.
 166  */
 167 #define UCI_THROW(ctx, err) do {        \
 168         DPRINTF("Exception: %s in %s, %s:%d\n", #err, __func__, __FILE__, __LINE__); \
 169         longjmp(ctx->trap, err);        \
 170 } while (0)
 171
 172 /*
 173  * store the return address for handling exceptions
 174  * needs to be called in every externally visible library function
 175  *
 176  * NB: this does not handle recursion at all. Calling externally visible
 177  * functions from other uci functions is only allowed at the end of the
 178  * calling function, or by wrapping the function call in UCI_TRAP_SAVE
 179  * and UCI_TRAP_RESTORE.
 180  */
 181 #define UCI_HANDLE_ERR(ctx) do {        \
 182         DPRINTF("ENTER: %s\n", __func__); \
 183         int __val = 0;                  \
 184         if (!ctx)                       \
 185                 return UCI_ERR_INVAL;   \
 186         ctx->err = 0;                   \
 187         if (!ctx->internal && !ctx->nested) \
 188                 __val = setjmp(ctx->trap); \
 189         ctx->internal = false;          \
 190         ctx->nested = false;            \
 191         if (__val) {                    \
 192                 DPRINTF("LEAVE: %s, ret=%d\n", __func__, __val); \
 193                 ctx->err = __val;       \
 194                 return __val;           \
 195         }                               \
 196 } while (0)
 197
 198 /*
 199  * In a block enclosed by UCI_TRAP_SAVE and UCI_TRAP_RESTORE, all exceptions
 200  * are intercepted and redirected to the label specified in 'handler'
 201  * after UCI_TRAP_RESTORE, or when reaching the 'handler' label, the old
 202  * exception handler is restored
 203  */
 204 #define UCI_TRAP_SAVE(ctx, handler) do {   \
 205         jmp_buf __old_trap;             \
 206         int __val;                      \
 207         memcpy(__old_trap, ctx->trap, sizeof(ctx->trap)); \
 208         __val = setjmp(ctx->trap);      \
 209         if (__val) {                    \
 210                 ctx->err = __val;       \
 211                 memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
 212                 goto handler;           \
 213         }
 214 #define UCI_TRAP_RESTORE(ctx)           \
 215         memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
 216 } while(0)
 217
 218 /**
 219  * UCI_INTERNAL: Do an internal call of a public API function
 220  *
 221  * Sets Exception handling to passthrough mode.
 222  * Allows API functions to change behavior compared to public use
 223  */
 224 #define UCI_INTERNAL(func, ctx, ...) do { \
 225         ctx->internal = true;           \
 226         func(ctx, __VA_ARGS__);         \
 227 } while (0)
 228
 229 /**
 230  * UCI_NESTED: Do an normal nested call of a public API function
 231  *
 232  * Sets Exception handling to passthrough mode.
 233  * Allows API functions to change behavior compared to public use
 234  */
 235 #define UCI_NESTED(func, ctx, ...) do { \
 236         ctx->nested = true;             \
 237         func(ctx, __VA_ARGS__);         \
 238 } while (0)
 239
 240
 241 /*
 242  * check the specified condition.
 243  * throw an invalid argument exception if it's false
 244  */
 245 #define UCI_ASSERT(ctx, expr) do {      \
 246         if (!(expr)) {                  \
 247                 DPRINTF("[%s:%d] Assertion failed\n", __FILE__, __LINE__); \
 248                 UCI_THROW(ctx, UCI_ERR_INVAL);  \
 249         }                               \
 250 } while (0)
 251
 252 #endif