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 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 #ifdef UCI_PLUGIN_SUPPORT
  21 #define __plugin extern
  22 #else
  23 #define __plugin static
  24 #endif
  25
  26 struct uci_parse_context
  27 {
  28         /* error context */
  29         const char *reason;
  30         int line;
  31         int byte;
  32
  33         /* private: */
  34         struct uci_package *package;
  35         struct uci_section *section;
  36         bool merge;
  37         FILE *file;
  38         const char *name;
  39         char *buf;
  40         int bufsz;
  41 };
  42
  43 __plugin void *uci_malloc(struct uci_context *ctx, size_t size);
  44 __plugin void *uci_realloc(struct uci_context *ctx, void *ptr, size_t size);
  45 __plugin char *uci_strdup(struct uci_context *ctx, const char *str);
  46 __plugin bool uci_validate_str(const char *str, bool name);
  47 __plugin void uci_add_history(struct uci_context *ctx, struct uci_list *list, int cmd, const char *section, const char *option, const char *value);
  48 __plugin void uci_free_history(struct uci_history *h);
  49 __plugin struct uci_package *uci_alloc_package(struct uci_context *ctx, const char *name);
  50
  51 __private FILE *uci_open_stream(struct uci_context *ctx, const char *filename, int pos, bool write, bool create);
  52 __private void uci_close_stream(FILE *stream);
  53 __private void uci_getln(struct uci_context *ctx, int offset);
  54
  55 __private void uci_parse_error(struct uci_context *ctx, char *pos, char *reason);
  56 __private void uci_alloc_parse_context(struct uci_context *ctx);
  57
  58 __private void uci_cleanup(struct uci_context *ctx);
  59 __private struct uci_element *uci_lookup_list(struct uci_list *list, const char *name);
  60 __private void uci_fixup_section(struct uci_context *ctx, struct uci_section *s);
  61 __private void uci_free_package(struct uci_package **package);
  62
  63 __private int uci_load_history(struct uci_context *ctx, struct uci_package *p, bool flush);
  64
  65 static inline bool uci_validate_package(const char *str)
  66 {
  67         return uci_validate_str(str, false);
  68 }
  69
  70 static inline bool uci_validate_type(const char *str)
  71 {
  72         return uci_validate_str(str, false);
  73 }
  74
  75 static inline bool uci_validate_name(const char *str)
  76 {
  77         return uci_validate_str(str, true);
  78 }
  79
  80 /* initialize a list head/item */
  81 static inline void uci_list_init(struct uci_list *ptr)
  82 {
  83         ptr->prev = ptr;
  84         ptr->next = ptr;
  85 }
  86
  87 /* inserts a new list entry after a given entry */
  88 static inline void uci_list_insert(struct uci_list *list, struct uci_list *ptr)
  89 {
  90         list->next->prev = ptr;
  91         ptr->prev = list;
  92         ptr->next = list->next;
  93         list->next = ptr;
  94 }
  95
  96 /* inserts a new list entry at the tail of the list */
  97 static inline void uci_list_add(struct uci_list *head, struct uci_list *ptr)
  98 {
  99         /* NB: head->prev points at the tail */
 100         uci_list_insert(head->prev, ptr);
 101 }
 102
 103 static inline void uci_list_del(struct uci_list *ptr)
 104 {
 105         struct uci_list *next, *prev;
 106
 107         next = ptr->next;
 108         prev = ptr->prev;
 109
 110         prev->next = next;
 111         next->prev = prev;
 112
 113         uci_list_init(ptr);
 114 }
 115
 116
 117 extern struct uci_backend uci_file_backend;
 118
 119 #ifdef UCI_PLUGIN_SUPPORT
 120 /**
 121  * uci_add_backend: add an extra backend
 122  * @ctx: uci context
 123  * @name: name of the backend
 124  *
 125  * The default backend is "file", which uses /etc/config for config storage
 126  */
 127 __plugin int uci_add_backend(struct uci_context *ctx, struct uci_backend *b);
 128
 129 /**
 130  * uci_add_backend: add an extra backend
 131  * @ctx: uci context
 132  * @name: name of the backend
 133  *
 134  * The default backend is "file", which uses /etc/config for config storage
 135  */
 136 __plugin int uci_del_backend(struct uci_context *ctx, struct uci_backend *b);
 137 #endif
 138
 139 #define UCI_BACKEND(_var, _name, ...)   \
 140 struct uci_backend _var = {             \
 141         .e.list = {                     \
 142                 .next = &_var.e.list,   \
 143                 .prev = &_var.e.list,   \
 144         },                              \
 145         .e.name = _name,                \
 146         .e.type = UCI_TYPE_BACKEND,     \
 147         .ptr = &_var,                   \
 148         __VA_ARGS__                     \
 149 }
 150
 151
 152 /*
 153  * functions for debug and error handling, for internal use only
 154  */
 155
 156 #ifdef UCI_DEBUG
 157 #define DPRINTF(...) fprintf(stderr, __VA_ARGS__)
 158 #else
 159 #define DPRINTF(...)
 160 #endif
 161
 162 /*
 163  * throw an uci exception and store the error number
 164  * in the context.
 165  */
 166 #define UCI_THROW(ctx, err) do {        \
 167         DPRINTF("Exception: %s in %s, %s:%d\n", #err, __func__, __FILE__, __LINE__); \
 168         longjmp(ctx->trap, err);        \
 169 } while (0)
 170
 171 /*
 172  * store the return address for handling exceptions
 173  * needs to be called in every externally visible library function
 174  *
 175  * NB: this does not handle recursion at all. Calling externally visible
 176  * functions from other uci functions is only allowed at the end of the
 177  * calling function, or by wrapping the function call in UCI_TRAP_SAVE
 178  * and UCI_TRAP_RESTORE.
 179  */
 180 #define UCI_HANDLE_ERR(ctx) do {        \
 181         DPRINTF("ENTER: %s\n", __func__); \
 182         int __val = 0;                  \
 183         ctx->err = 0;                   \
 184         if (!ctx)                       \
 185                 return UCI_ERR_INVAL;   \
 186         if (!ctx->internal && !ctx->nested) \
 187                 __val = setjmp(ctx->trap); \
 188         ctx->internal = false;          \
 189         ctx->nested = false;            \
 190         if (__val) {                    \
 191                 DPRINTF("LEAVE: %s, ret=%d\n", __func__, __val); \
 192                 ctx->err = __val;       \
 193                 return __val;           \
 194         }                               \
 195 } while (0)
 196
 197 /*
 198  * In a block enclosed by UCI_TRAP_SAVE and UCI_TRAP_RESTORE, all exceptions
 199  * are intercepted and redirected to the label specified in 'handler'
 200  * after UCI_TRAP_RESTORE, or when reaching the 'handler' label, the old
 201  * exception handler is restored
 202  */
 203 #define UCI_TRAP_SAVE(ctx, handler) do {   \
 204         jmp_buf __old_trap;             \
 205         int __val;                      \
 206         memcpy(__old_trap, ctx->trap, sizeof(ctx->trap)); \
 207         __val = setjmp(ctx->trap);      \
 208         if (__val) {                    \
 209                 ctx->err = __val;       \
 210                 memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
 211                 goto handler;           \
 212         }
 213 #define UCI_TRAP_RESTORE(ctx)           \
 214         memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
 215 } while(0)
 216
 217 /**
 218  * UCI_INTERNAL: Do an internal call of a public API function
 219  *
 220  * Sets Exception handling to passthrough mode.
 221  * Allows API functions to change behavior compared to public use
 222  */
 223 #define UCI_INTERNAL(func, ctx, ...) do { \
 224         ctx->internal = true;           \
 225         func(ctx, __VA_ARGS__);         \
 226 } while (0)
 227
 228 /**
 229  * UCI_NESTED: Do an normal nested call of a public API function
 230  *
 231  * Sets Exception handling to passthrough mode.
 232  * Allows API functions to change behavior compared to public use
 233  */
 234 #define UCI_NESTED(func, ctx, ...) do { \
 235         ctx->nested = true;             \
 236         func(ctx, __VA_ARGS__);         \
 237 } while (0)
 238
 239
 240 /*
 241  * check the specified condition.
 242  * throw an invalid argument exception if it's false
 243  */
 244 #define UCI_ASSERT(ctx, expr) do {      \
 245         if (!(expr)) {                  \
 246                 DPRINTF("[%s:%d] Assertion failed\n", __FILE__, __LINE__); \
 247                 UCI_THROW(ctx, UCI_ERR_INVAL);  \
 248         }                               \
 249 } while (0)
 250
 251 #endif