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Code Issues Releases Activity

eh_elf: implement mmap_get_entry

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This commit is contained in:
Théophile Bastian 2018-05-31 12:52:49 +02:00
parent 8b7b8659ec
commit a02324d9af
2 changed files with 43 additions and 2 deletions
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38
src/eh_elf/memory_map.c
View file

@ -7,11 +7,16 @@
static mmap_entry_t* _memory_map = NULL;
static size_t _memory_map_size = 0;
static int _mmap_init_done = 0;
/// Init the memory map with a given /proc/XX/ argument
int mmap_init_procdir(const char* procdir);
static int compare_mmap_entry(const void* e1, const void* e2) {
return ((mmap_entry_t*)e1)->beg_ip - ((mmap_entry_t*)e2)->beg_ip;
}
int mmap_init_local() {
return mmap_init_procdir("/proc/self/");
}
@ -80,6 +85,10 @@ int mmap_init_procdir(const char* procdir) {
_memory_map = (mmap_entry_t*)
realloc(_memory_map, _memory_map_size * sizeof(mmap_entry_t));
// Ensure the entries are sorted by ascending ip range
qsort(_memory_map, _memory_map_size, sizeof(mmap_entry_t),
compare_mmap_entry);
// dlopen corresponding eh_elf objects
for(size_t id = 0; id < _memory_map_size; ++id) {
char eh_elf_path[256];
@ -88,10 +97,14 @@ int mmap_init_procdir(const char* procdir) {
_memory_map[id].eh_elf = dlopen(eh_elf_path, RTLD_LAZY);
}
_mmap_init_done = 1;
return 0;
}
void mmap_clear() {
_mmap_init_done = 0;
if(_memory_map != NULL) {
for(size_t pos=0; pos < _memory_map_size; ++pos) {
free(_memory_map[pos].object_name);
@ -100,3 +113,28 @@ void mmap_clear() {
free(_memory_map);
}
}
static int bsearch_compar_mmap_entry(const void* vkey, const void* vmmap_elt) {
uintptr_t key = *(uintptr_t*)vkey;
const mmap_entry_t* mmap_elt = (const mmap_entry_t*) vmmap_elt;
if(mmap_elt->beg_ip <= key && key < mmap_elt->end_ip)
return 0;
if(key < mmap_elt->beg_ip)
return -1;
return 1;
}
mmap_entry_t* mmap_get_entry(uintptr_t ip) {
// Perform a binary search to find the requested ip
if(!_mmap_init_done)
return NULL;
return bsearch(
(void*)&ip,
(void*)_memory_map,
_memory_map_size,
sizeof(mmap_entry_t),
bsearch_compar_mmap_entry);
}

7
src/eh_elf/memory_map.h
View file

@ -44,5 +44,8 @@ int mmap_init_local();
**/
int mmap_init_pid(pid_t pid);
/// Get the `mmap_entry_t` corresponding to the given IP
int mmap_get_entry(uintptr_t ip, mmap_entry_t* entry);
/** Get the `mmap_entry_t` corresponding to the given IP
* @return a pointer to the corresponding memory map entry, or NULL upon
* failure.
**/
mmap_entry_t* mmap_get_entry(uintptr_t ip);