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         int pos;
  37 };
  38 #define pctx_pos(pctx)          ((pctx)->pos)
  39 #define pctx_str(pctx, i)       (&(pctx)->buf[(i)])
  40 #define pctx_cur_str(pctx)      pctx_str(pctx, pctx_pos(pctx))
  41 #define pctx_char(pctx, i)      ((pctx)->buf[(i)])
  42 #define pctx_cur_char(pctx)     pctx_char(pctx, pctx_pos(pctx))
  43
  44 extern const char *uci_confdir;
  45 extern const char *uci_savedir;
  46
  47 __private void *uci_malloc(struct uci_context *ctx, size_t size);
  48 __private void *uci_realloc(struct uci_context *ctx, void *ptr, size_t size);
  49 __private char *uci_strdup(struct uci_context *ctx, const char *str);
  50 __private bool uci_validate_str(const char *str, bool name, bool package);
  51 __private void uci_add_delta(struct uci_context *ctx, struct uci_list *list, int cmd, const char *section, const char *option, const char *value);
  52 __private void uci_free_delta(struct uci_delta *h);
  53 __private struct uci_package *uci_alloc_package(struct uci_context *ctx, const char *name);
  54
  55 __private FILE *uci_open_stream(struct uci_context *ctx, const char *filename, const char *origfilename, int pos, bool write, bool create);
  56 __private void uci_close_stream(FILE *stream);
  57 __private void uci_getln(struct uci_context *ctx, int offset);
  58
  59 __private void uci_parse_error(struct uci_context *ctx, char *reason);
  60 __private void uci_alloc_parse_context(struct uci_context *ctx);
  61
  62 __private void uci_cleanup(struct uci_context *ctx);
  63 __private struct uci_element *uci_lookup_list(struct uci_list *list, const char *name);
  64 __private void uci_free_package(struct uci_package **package);
  65 __private struct uci_element *uci_alloc_generic(struct uci_context *ctx, int type, const char *name, int size);
  66 __private void uci_free_element(struct uci_element *e);
  67 __private struct uci_element *uci_expand_ptr(struct uci_context *ctx, struct uci_ptr *ptr, bool complete);
  68
  69 __private int uci_load_delta(struct uci_context *ctx, struct uci_package *p, bool flush);
  70
  71 static inline bool uci_validate_package(const char *str)
  72 {
  73         return uci_validate_str(str, false, true);
  74 }
  75
  76 static inline bool uci_validate_type(const char *str)
  77 {
  78         return uci_validate_str(str, false, false);
  79 }
  80
  81 static inline bool uci_validate_name(const char *str)
  82 {
  83         return uci_validate_str(str, true, false);
  84 }
  85
  86 /* initialize a list head/item */
  87 static inline void uci_list_init(struct uci_list *ptr)
  88 {
  89         ptr->prev = ptr;
  90         ptr->next = ptr;
  91 }
  92
  93 /* inserts a new list entry after a given entry */
  94 static inline void uci_list_insert(struct uci_list *list, struct uci_list *ptr)
  95 {
  96         list->next->prev = ptr;
  97         ptr->prev = list;
  98         ptr->next = list->next;
  99         list->next = ptr;
 100 }
 101
 102 /* inserts a new list entry at the tail of the list */
 103 static inline void uci_list_add(struct uci_list *head, struct uci_list *ptr)
 104 {
 105         /* NB: head->prev points at the tail */
 106         uci_list_insert(head->prev, ptr);
 107 }
 108
 109 static inline void uci_list_del(struct uci_list *ptr)
 110 {
 111         struct uci_list *next, *prev;
 112
 113         next = ptr->next;
 114         prev = ptr->prev;
 115
 116         prev->next = next;
 117         next->prev = prev;
 118
 119         uci_list_init(ptr);
 120 }
 121
 122
 123 extern struct uci_backend uci_file_backend;
 124
 125 #ifdef UCI_PLUGIN_SUPPORT
 126 /**
 127  * uci_add_backend: add an extra backend
 128  * @ctx: uci context
 129  * @name: name of the backend
 130  *
 131  * The default backend is "file", which uses /etc/config for config storage
 132  */
 133 __private int uci_add_backend(struct uci_context *ctx, struct uci_backend *b);
 134
 135 /**
 136  * uci_add_backend: add an extra backend
 137  * @ctx: uci context
 138  * @name: name of the backend
 139  *
 140  * The default backend is "file", which uses /etc/config for config storage
 141  */
 142 __private int uci_del_backend(struct uci_context *ctx, struct uci_backend *b);
 143 #endif
 144
 145 #define UCI_BACKEND(_var, _name, ...)   \
 146 struct uci_backend _var = {             \
 147         .e.list = {                     \
 148                 .next = &_var.e.list,   \
 149                 .prev = &_var.e.list,   \
 150         },                              \
 151         .e.name = _name,                \
 152         .e.type = UCI_TYPE_BACKEND,     \
 153         .ptr = &_var,                   \
 154         __VA_ARGS__                     \
 155 }
 156
 157
 158 /*
 159  * functions for debug and error handling, for internal use only
 160  */
 161
 162 #ifdef UCI_DEBUG
 163 #define DPRINTF(...) fprintf(stderr, __VA_ARGS__)
 164 #else
 165 #define DPRINTF(...)
 166 #endif
 167
 168 /*
 169  * throw an uci exception and store the error number
 170  * in the context.
 171  */
 172 #define UCI_THROW(ctx, err) do {        \
 173         DPRINTF("Exception: %s in %s, %s:%d\n", #err, __func__, __FILE__, __LINE__); \
 174         longjmp(ctx->trap, err);        \
 175 } while (0)
 176
 177 /*
 178  * store the return address for handling exceptions
 179  * needs to be called in every externally visible library function
 180  *
 181  * NB: this does not handle recursion at all. Calling externally visible
 182  * functions from other uci functions is only allowed at the end of the
 183  * calling function, or by wrapping the function call in UCI_TRAP_SAVE
 184  * and UCI_TRAP_RESTORE.
 185  */
 186 #define UCI_HANDLE_ERR(ctx) do {        \
 187         DPRINTF("ENTER: %s\n", __func__); \
 188         int __val = 0;                  \
 189         if (!ctx)                       \
 190                 return UCI_ERR_INVAL;   \
 191         ctx->err = 0;                   \
 192         if (!ctx->internal && !ctx->nested) \
 193                 __val = setjmp(ctx->trap); \
 194         ctx->internal = false;          \
 195         ctx->nested = false;            \
 196         if (__val) {                    \
 197                 DPRINTF("LEAVE: %s, ret=%d\n", __func__, __val); \
 198                 ctx->err = __val;       \
 199                 return __val;           \
 200         }                               \
 201 } while (0)
 202
 203 /*
 204  * In a block enclosed by UCI_TRAP_SAVE and UCI_TRAP_RESTORE, all exceptions
 205  * are intercepted and redirected to the label specified in 'handler'
 206  * after UCI_TRAP_RESTORE, or when reaching the 'handler' label, the old
 207  * exception handler is restored
 208  */
 209 #define UCI_TRAP_SAVE(ctx, handler) do {   \
 210         jmp_buf __old_trap;             \
 211         int __val;                      \
 212         memcpy(__old_trap, ctx->trap, sizeof(ctx->trap)); \
 213         __val = setjmp(ctx->trap);      \
 214         if (__val) {                    \
 215                 ctx->err = __val;       \
 216                 memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
 217                 goto handler;           \
 218         }
 219 #define UCI_TRAP_RESTORE(ctx)           \
 220         memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
 221 } while(0)
 222
 223 /**
 224  * UCI_INTERNAL: Do an internal call of a public API function
 225  *
 226  * Sets Exception handling to passthrough mode.
 227  * Allows API functions to change behavior compared to public use
 228  */
 229 #define UCI_INTERNAL(func, ctx, ...) do { \
 230         ctx->internal = true;           \
 231         func(ctx, __VA_ARGS__);         \
 232 } while (0)
 233
 234 /**
 235  * UCI_NESTED: Do an normal nested call of a public API function
 236  *
 237  * Sets Exception handling to passthrough mode.
 238  * Allows API functions to change behavior compared to public use
 239  */
 240 #define UCI_NESTED(func, ctx, ...) do { \
 241         ctx->nested = true;             \
 242         func(ctx, __VA_ARGS__);         \
 243 } while (0)
 244
 245
 246 /*
 247  * check the specified condition.
 248  * throw an invalid argument exception if it's false
 249  */
 250 #define UCI_ASSERT(ctx, expr) do {      \
 251         if (!(expr)) {                  \
 252                 DPRINTF("[%s:%d] Assertion failed\n", __FILE__, __LINE__); \
 253                 UCI_THROW(ctx, UCI_ERR_INVAL);  \
 254         }                               \
 255 } while (0)
 256
 257 #endif