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/* -*- linux-c -*-
* Symbolic Lookup Functions
* Copyright (C) 2005, 2006, 2007 Red Hat Inc.
* Copyright (C) 2006 Intel Corporation.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#ifndef _SYM_C_
#define _SYM_C_
#include "string.c"
/** @file sym.c
* @addtogroup sym Symbolic Functions
* Symbolic Lookup Functions
* @{
*/
unsigned long _stp_module_relocate (const char *module, const char *section, unsigned long offset) {
static struct _stp_module *last = NULL;
static struct _stp_symbol *last_sec;
unsigned long flags;
int i,j;
/* if module is -1, we invalidate last. _stp_del_module calls this when modules are deleted. */
if ((long)module == -1) {
last = NULL;
return 0;
}
dbug("_stp_relocate_module: %s, %s, %lx\n", module, section, offset);
STP_LOCK_MODULES;
if (! module
|| !strcmp (section, "") /* absolute, unrelocated address */
|| _stp_num_modules == 0) {
STP_UNLOCK_MODULES;
return offset;
}
/* Most likely our relocation is in the same section of the same module as the last. */
if (last) {
if (!strcmp (module, last->name) && !strcmp (section, last_sec->symbol)) {
offset += last_sec->addr;
STP_UNLOCK_MODULES;
return offset;
}
}
/* not cached. need to scan all modules */
if (! strcmp (module, "kernel")) {
STP_UNLOCK_MODULES;
/* See also transport/symbols.c (_stp_do_symbols). */
if (strcmp (section, "_stext"))
return 0;
else
return offset + _stp_modules[0]->text;
} else {
/* relocatable module */
for (i = 1; i < _stp_num_modules; i++) { /* skip over [0]=kernel */
last = _stp_modules[i];
if (strcmp(module, last->name))
continue;
for (j = 0; j < (int)last->num_sections; j++) {
last_sec = &last->sections[j];
if (!strcmp (section, last_sec->symbol)) {
offset += last_sec->addr;
STP_UNLOCK_MODULES;
return offset;
}
}
}
}
STP_UNLOCK_MODULES;
last = NULL;
return 0;
}
/* Lookup the kernel address for this symbol. Returns 0 if not found. */
static unsigned long _stp_kallsyms_lookup_name(const char *name)
{
struct _stp_symbol *s = _stp_modules[0]->symbols;
unsigned num = _stp_modules[0]->num_symbols;
while (num--) {
if (strcmp(name, s->symbol) == 0)
return s->addr;
s++;
}
return 0;
}
static const char * _stp_kallsyms_lookup (
unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset,
char **modname,
char *namebuf)
{
struct _stp_module *m;
struct _stp_symbol *s;
unsigned long flags;
unsigned end, begin = 0;
if (STP_TRYLOCK_MODULES)
return NULL;
end = _stp_num_modules;
if (_stp_num_modules >= 2 && addr > _stp_modules_by_addr[1]->text) {
/* binary search on index [begin,end) */
do {
unsigned mid = (begin + end) / 2;
if (addr < _stp_modules_by_addr[mid]->text)
end = mid;
else
begin = mid;
} while (begin + 1 < end);
/* result index in $begin, guaranteed between [0,_stp_num_modules) */
}
m = _stp_modules_by_addr[begin];
begin = 0;
end = m->num_symbols;
/* binary search for symbols within the module */
do {
unsigned mid = (begin + end) / 2;
if (addr < m->symbols[mid].addr)
end = mid;
else
begin = mid;
} while (begin + 1 < end);
/* result index in $begin */
s = &m->symbols[begin];
if (addr < s->addr) {
STP_UNLOCK_MODULES;
return NULL;
} else {
if (offset) *offset = addr - s->addr;
if (modname) *modname = m->name;
if (symbolsize) {
if ((begin + 1) < m->num_symbols)
*symbolsize = m->symbols[begin+1].addr - s->addr;
else
*symbolsize = 0;
// NB: This is only a heuristic. Sometimes there are large
// gaps between text areas of modules.
}
if (namebuf) {
strlcpy (namebuf, s->symbol, KSYM_NAME_LEN+1);
STP_UNLOCK_MODULES;
return namebuf;
}
else {
STP_UNLOCK_MODULES;
return s->symbol;
}
}
STP_UNLOCK_MODULES;
return NULL;
}
/** Print an address symbolically.
* @param address The address to lookup.
* @note Symbolic lookups should not normally be done within
* a probe because it is too time-consuming. Use at module exit time.
*/
void _stp_symbol_print (unsigned long address)
{
char *modname;
const char *name;
unsigned long offset, size;
name = _stp_kallsyms_lookup(address, &size, &offset, &modname, NULL);
_stp_printf ("%p", (int64_t)address);
if (name) {
if (modname)
_stp_printf (" : %s+%#lx/%#lx [%s]", name, offset, size, modname);
else
_stp_printf (" : %s+%#lx/%#lx", name, offset, size);
}
}
void _stp_symbol_snprint (char *str, size_t len, unsigned long address)
{
char *modname;
const char *name;
unsigned long offset, size;
name = _stp_kallsyms_lookup(address, &size, &offset, &modname, NULL);
if (name)
strlcpy(str, name, len);
else
_stp_snprintf(str, len, "%p", (int64_t)address);
}
/** @} */
#endif /* _SYM_C_ */
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