我正在使用uthash.h来存储我的应用程序的配置。由于配置来自运行时读取的文件,因此哈希中的键和值都是动态分配char *
的:
typedef struct config_entry {
char *name;
char *value;
UT_hash_handle hh;
} CONFIG_ENTRY;
正如用户指南中所解释的,我实现了自己的函数来向 config-hash 添加键以确保唯一性。这里是:
void cfg_put( char *name, char *value, FREE_FLAGS flags ) {
CONFIG_ENTRY *entry;
//first, check if the key is already in the hash
HASH_FIND_STR( config_, name, entry );
if( entry == NULL ) {
//key doesn't exist yet => create new one
entry = (CONFIG_ENTRY *)malloc( sizeof( CONFIG_ENTRY ) );
entry->name = name;
HASH_ADD_KEYPTR( hh, config_, entry->name, strlen(entry->name), entry );
} else {
//key exists => possibly free existing pointers before setting value
if( (flags & FREE_NAME) == FREE_NAME ) { //
free( entry->name ); // these lines seem to be
} // problematic.
entry->name = name; //
if( (flags & FREE_VALUE) == FREE_VALUE ) {
free( entry->value );
}
}
//Finally, set the value
entry->value = value;
}
我还写了一些测试用例来检查我的实现,它们似乎运行得很好。但是,如果我使用 valgrind 运行测试来检查 memleaks,我总是会得到以下信息:
==2561== Invalid read of size 1
==2561== at 0x4026097: bcmp (mc_replace_strmem.c:541)
==2561== by 0x804ADF5: cfg_get (in /home/gj/..../test/config_test)
==2561== by 0x804B2C7: test_config1 (in /home/..../test/config_test)
==2561== by 0x402E446: run_single_test (in /usr/local/lib/libcunit.so.1.0.1)
[...]
==2561== Address 0x4194210 is 0 bytes inside a block of size 4 free'd
==2561== at 0x4023B6A: free (vg_replace_malloc.c:366)
==2561== by 0x804A872: cfg_put (in /home/..../test/config_test)
==2561== by 0x804B27D: test_config1 (in /home/..../test/config_test)
==2561== by 0x402E446: run_single_test (in /usr/local/lib/libcunit.so.1.0.1)
[...]
这是测试用例和完整性的实现cfg_get
:
void test_config1( void ) {
cfg_clear( FREE_ALL );
cfg_put( strdup("foo"), "bar", FREE_NONE );
CU_ASSERT_EQUAL( cfg_count(), 1 );
CU_ASSERT_STRING_EQUAL( cfg_get("foo"), "bar" );
cfg_dump();
cfg_put( "foo", "baz", FREE_NAME );
CU_ASSERT_EQUAL( cfg_count(), 2 );
CU_ASSERT_STRING_EQUAL( cfg_get("foo"), "baz" );
cfg_clear( FREE_NONE );
cfg_dump();
}
cfg_get
:
char *cfg_get( const char *name ) {
CONFIG_ENTRY *entry = NULL;
HASH_FIND_STR( config_, name, entry );
if( entry ) {
return entry->value;
} else {
return NULL;
}
}
不知何故,似乎我在将旧name
指针cfg_get
覆盖在cfg_put
. 问题只出现在 中name
,而不出现在 中value
。我太愚蠢了,无法弄清楚,谢谢任何建议。