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         size_t 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         size_t bufsz;
  36         size_t buf_filled;
  37         size_t pos;
  38 };
  39 #define pctx_pos(pctx)          ((pctx)->pos)
  40 #define pctx_str(pctx, i)       (&(pctx)->buf[(i)])
  41 #define pctx_cur_str(pctx)      pctx_str(pctx, pctx_pos(pctx))
  42 #define pctx_char(pctx, i)      ((pctx)->buf[(i)])
  43 #define pctx_cur_char(pctx)     pctx_char(pctx, pctx_pos(pctx))
  44
  45 #define uci_alloc_element(ctx, type, name, datasize) \
  46         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
  47
  48 extern const char *uci_confdir;
  49 extern const char *uci_savedir;
  50
  51 __private void *uci_malloc(struct uci_context *ctx, size_t size);
  52 __private void *uci_realloc(struct uci_context *ctx, void *ptr, size_t size);
  53 __private char *uci_strdup(struct uci_context *ctx, const char *str);
  54 __private bool uci_validate_str(const char *str, bool name, bool package);
  55 __private void uci_add_delta(struct uci_context *ctx, struct uci_list *list, int cmd, const char *section, const char *option, const char *value);
  56 __private void uci_free_delta(struct uci_delta *h);
  57 __private struct uci_package *uci_alloc_package(struct uci_context *ctx, const char *name);
  58
  59 __private FILE *uci_open_stream(struct uci_context *ctx, const char *filename, const char *origfilename, int pos, bool write, bool create);
  60 __private void uci_close_stream(FILE *stream);
  61 __private void uci_getln(struct uci_context *ctx, size_t offset);
  62
  63 __private void uci_parse_error(struct uci_context *ctx, char *reason);
  64 __private void uci_alloc_parse_context(struct uci_context *ctx);
  65
  66 __private void uci_cleanup(struct uci_context *ctx);
  67 __private struct uci_element *uci_lookup_list(struct uci_list *list, const char *name);
  68 __private void uci_free_package(struct uci_package **package);
  69 __private struct uci_element *uci_alloc_generic(struct uci_context *ctx, int type, const char *name, int size);
  70 __private void uci_free_element(struct uci_element *e);
  71 __private struct uci_element *uci_expand_ptr(struct uci_context *ctx, struct uci_ptr *ptr, bool complete);
  72
  73 __private int uci_load_delta(struct uci_context *ctx, struct uci_package *p, bool flush);
  74
  75 static inline bool uci_validate_package(const char *str)
  76 {
  77         return uci_validate_str(str, false, true);
  78 }
  79
  80 static inline bool uci_validate_type(const char *str)
  81 {
  82         return uci_validate_str(str, false, false);
  83 }
  84
  85 static inline bool uci_validate_name(const char *str)
  86 {
  87         return uci_validate_str(str, true, false);
  88 }
  89
  90 /* initialize a list head/item */
  91 static inline void uci_list_init(struct uci_list *ptr)
  92 {
  93         ptr->prev = ptr;
  94         ptr->next = ptr;
  95 }
  96
  97 /* inserts a new list entry after a given entry */
  98 static inline void uci_list_insert(struct uci_list *list, struct uci_list *ptr)
  99 {
 100         list->next->prev = ptr;
 101         ptr->prev = list;
 102         ptr->next = list->next;
 103         list->next = ptr;
 104 }
 105
 106 /* inserts a new list entry at the tail of the list */
 107 static inline void uci_list_add(struct uci_list *head, struct uci_list *ptr)
 108 {
 109         /* NB: head->prev points at the tail */
 110         uci_list_insert(head->prev, ptr);
 111 }
 112
 113 static inline void uci_list_del(struct uci_list *ptr)
 114 {
 115         struct uci_list *next, *prev;
 116
 117         next = ptr->next;
 118         prev = ptr->prev;
 119
 120         prev->next = next;
 121         next->prev = prev;
 122
 123         uci_list_init(ptr);
 124 }
 125
 126
 127 extern struct uci_backend uci_file_backend;
 128
 129 #ifdef UCI_PLUGIN_SUPPORT
 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_add_backend(struct uci_context *ctx, struct uci_backend *b);
 138
 139 /**
 140  * uci_add_backend: add an extra backend
 141  * @ctx: uci context
 142  * @name: name of the backend
 143  *
 144  * The default backend is "file", which uses /etc/config for config storage
 145  */
 146 __private int uci_del_backend(struct uci_context *ctx, struct uci_backend *b);
 147 #endif
 148
 149 #define UCI_BACKEND(_var, _name, ...)   \
 150 struct uci_backend _var = {             \
 151         .e.list = {                     \
 152                 .next = &_var.e.list,   \
 153                 .prev = &_var.e.list,   \
 154         },                              \
 155         .e.name = _name,                \
 156         .e.type = UCI_TYPE_BACKEND,     \
 157         .ptr = &_var,                   \
 158         __VA_ARGS__                     \
 159 }
 160
 161
 162 /*
 163  * functions for debug and error handling, for internal use only
 164  */
 165
 166 #ifdef UCI_DEBUG
 167 #define DPRINTF(...) fprintf(stderr, __VA_ARGS__)
 168 #else
 169 #define DPRINTF(...)
 170 #endif
 171
 172 /*
 173  * throw an uci exception and store the error number
 174  * in the context.
 175  */
 176 #define UCI_THROW(ctx, err) do {        \
 177         DPRINTF("Exception: %s in %s, %s:%d\n", #err, __func__, __FILE__, __LINE__); \
 178         longjmp(ctx->trap, err);        \
 179 } while (0)
 180
 181 /*
 182  * store the return address for handling exceptions
 183  * needs to be called in every externally visible library function
 184  *
 185  * NB: this does not handle recursion at all. Calling externally visible
 186  * functions from other uci functions is only allowed at the end of the
 187  * calling function, or by wrapping the function call in UCI_TRAP_SAVE
 188  * and UCI_TRAP_RESTORE.
 189  */
 190 #define UCI_HANDLE_ERR(ctx) do {        \
 191         DPRINTF("ENTER: %s\n", __func__); \
 192         int __val = 0;                  \
 193         if (!ctx)                       \
 194                 return UCI_ERR_INVAL;   \
 195         ctx->err = 0;                   \
 196         if (!ctx->internal && !ctx->nested) \
 197                 __val = setjmp(ctx->trap); \
 198         ctx->internal = false;          \
 199         ctx->nested = false;            \
 200         if (__val) {                    \
 201                 DPRINTF("LEAVE: %s, ret=%d\n", __func__, __val); \
 202                 ctx->err = __val;       \
 203                 return __val;           \
 204         }                               \
 205 } while (0)
 206
 207 /*
 208  * In a block enclosed by UCI_TRAP_SAVE and UCI_TRAP_RESTORE, all exceptions
 209  * are intercepted and redirected to the label specified in 'handler'
 210  * after UCI_TRAP_RESTORE, or when reaching the 'handler' label, the old
 211  * exception handler is restored
 212  */
 213 #define UCI_TRAP_SAVE(ctx, handler) do {   \
 214         jmp_buf __old_trap;             \
 215         int __val;                      \
 216         memcpy(__old_trap, ctx->trap, sizeof(ctx->trap)); \
 217         __val = setjmp(ctx->trap);      \
 218         if (__val) {                    \
 219                 ctx->err = __val;       \
 220                 memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
 221                 goto handler;           \
 222         } while(0)
 223 #define UCI_TRAP_RESTORE(ctx)           \
 224         memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
 225 } while(0)
 226
 227 /**
 228  * UCI_INTERNAL: Do an internal call of a public API function
 229  *
 230  * Sets Exception handling to passthrough mode.
 231  * Allows API functions to change behavior compared to public use
 232  */
 233 #define UCI_INTERNAL(func, ctx, ...) do { \
 234         ctx->internal = true;           \
 235         func(ctx, __VA_ARGS__);         \
 236 } while (0)
 237
 238 /**
 239  * UCI_NESTED: Do an normal nested call of a public API function
 240  *
 241  * Sets Exception handling to passthrough mode.
 242  * Allows API functions to change behavior compared to public use
 243  */
 244 #define UCI_NESTED(func, ctx, ...) do { \
 245         ctx->nested = true;             \
 246         func(ctx, __VA_ARGS__);         \
 247 } while (0)
 248
 249
 250 /*
 251  * check the specified condition.
 252  * throw an invalid argument exception if it's false
 253  */
 254 #define UCI_ASSERT(ctx, expr) do {      \
 255         if (!(expr)) {                  \
 256                 DPRINTF("[%s:%d] Assertion failed\n", __FILE__, __LINE__); \
 257                 UCI_THROW(ctx, UCI_ERR_INVAL);  \
 258         }                               \
 259 } while (0)
 260
 261 #endif