err.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 /*
  16  * functions for debug and error handling, for internal use only
  17  */
  18
  19 #ifdef UCI_DEBUG
  20 #define DPRINTF(...) fprintf(stderr, __VA_ARGS__)
  21 #else
  22 #define DPRINTF(...)
  23 #endif
  24
  25 /*
  26  * throw an uci exception and store the error number
  27  * in the context.
  28  */
  29 #define UCI_THROW(ctx, err) do {        \
  30         DPRINTF("Exception: %s in %s, %s:%d\n", #err, __func__, __FILE__, __LINE__); \
  31         longjmp(ctx->trap, err);        \
  32 } while (0)
  33
  34 /*
  35  * store the return address for handling exceptions
  36  * needs to be called in every externally visible library function
  37  *
  38  * NB: this does not handle recursion at all. Calling externally visible
  39  * functions from other uci functions is only allowed at the end of the
  40  * calling function, or by wrapping the function call in UCI_TRAP_SAVE
  41  * and UCI_TRAP_RESTORE.
  42  */
  43 #define UCI_HANDLE_ERR(ctx) do {        \
  44         DPRINTF("ENTER: %s\n", __func__); \
  45         int __val = 0;                  \
  46         ctx->errno = 0;                 \
  47         if (!ctx)                       \
  48                 return UCI_ERR_INVAL;   \
  49         if (!ctx->internal)             \
  50                 __val = setjmp(ctx->trap); \
  51         ctx->internal = false;          \
  52         if (__val) {                    \
  53                 ctx->errno = __val;     \
  54                 return __val;           \
  55         }                               \
  56 } while (0)
  57
  58 /*
  59  * In a block enclosed by UCI_TRAP_SAVE and UCI_TRAP_RESTORE, all exceptions
  60  * are intercepted and redirected to the label specified in 'handler'
  61  * after UCI_TRAP_RESTORE, or when reaching the 'handler' label, the old
  62  * exception handler is restored
  63  */
  64 #define UCI_TRAP_SAVE(ctx, handler) do {   \
  65         jmp_buf __old_trap;             \
  66         int __val;                      \
  67         memcpy(__old_trap, ctx->trap, sizeof(ctx->trap)); \
  68         __val = setjmp(ctx->trap);      \
  69         if (__val) {                    \
  70                 ctx->errno = __val;     \
  71                 memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
  72                 goto handler;           \
  73         }
  74 #define UCI_TRAP_RESTORE(ctx)           \
  75         memcpy(ctx->trap, __old_trap, sizeof(ctx->trap)); \
  76 } while(0)
  77
  78 /**
  79  * UCI_INTERNAL: Do an internal call of a public API function
  80  *
  81  * Sets Exception handling to passthrough mode.
  82  * Allows API functions to change behavior compared to public use
  83  */
  84 #define UCI_INTERNAL(func, ctx, ...) do { \
  85         ctx->internal = true;           \
  86         func(ctx, __VA_ARGS__);         \
  87 } while (0)
  88
  89 /*
  90  * check the specified condition.
  91  * throw an invalid argument exception if it's false
  92  */
  93 #define UCI_ASSERT(ctx, expr) do {      \
  94         if (!(expr)) {                  \
  95                 DPRINTF("[%s:%d] Assertion failed\n", __FILE__, __LINE__); \
  96                 UCI_THROW(ctx, UCI_ERR_INVAL);  \
  97         }                               \
  98 } while (0)
  99