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#include <errno.h>
#include <string.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "config.h"
static __thread void *stack_start = NULL;
static __thread void *stack_end = NULL;
static unsigned long get_stack_size(struct lt_config_audit *cfg)
{
struct rlimit rlim;
if (getrlimit(RLIMIT_STACK, &rlim))
return 0;
PRINT_VERBOSE(cfg, 1, "stack cur size: %lx, max: %lx\n",
rlim.rlim_cur, rlim.rlim_max);
return rlim.rlim_cur;
}
/* find and update current stack boundaries */
static int load_stack(struct lt_config_audit *cfg, void *sp)
{
FILE *maps;
char line[128];
int found = 0;
void *start, *end;
unsigned long stack_size;
maps = fopen("/proc/self/maps", "r");
if (!maps) {
PRINT_VERBOSE(cfg, 1, "failed to open maps: %s\n",
strerror(errno));
return -1;
}
stack_size = get_stack_size(cfg);
/* XXX any sane idea what to do now ?*/
if (!stack_size)
return -1;
while (!found && fgets(line, sizeof(line), maps)) {
if (2 != sscanf(line, "%p-%p", &start, &end))
continue;
PRINT_VERBOSE(cfg, 1, "line start %p, end %p\n", start, end);
/* FIXME someone smart please figure out faster way,
* (somehow within the sscanf call?)
*
* Also what if the new stack is not GROWSDOWN,
* bounded by RLIMIT_STACK?
*/
if (strstr(line, "[stack]")) {
void *new_start = end - get_stack_size(cfg);
/* FIXME weird, need to investigate, looks like the stack
* area could grow more than the stack limit (eg for xpdf)
*
* taking the lower value for now
*/
if (new_start < start)
start = new_start;
}
found = ((start < sp) && (sp < end));
PRINT_VERBOSE(cfg, 1, "final start %p, end %p, sp %p, in %d\n",
start, end, sp, found);
}
fclose(maps);
if (found) {
stack_start = start;
stack_end = end;
}
return found ? 0 : -1;
}
/* check the current stack pointer and check its boundaries */
int lt_stack_framesize(struct lt_config_audit *cfg, La_regs *regs)
{
void *sp_top, *sp_bottom;
void *sp = (void*) regs->sp_reg;
unsigned int framesize = lt_sh(cfg, framesize);
if (!lt_sh(cfg, framesize_check))
return framesize;
/* got here first time, or we are out of bounds */
if (!stack_start ||
(sp < stack_start || sp > stack_end)) {
/* we are screeeeeewed */
if (load_stack(cfg, sp))
return framesize;
}
/* FIXME what about stacks growing up.. */
sp_top = sp + framesize;
if (sp_top > stack_end) {
framesize = stack_end - sp - 1;
PRINT_VERBOSE(cfg, 1,
"top reached, framesize changed to %lu\n",
framesize);
}
sp_bottom = sp - framesize;
if (sp_bottom < stack_start) {
framesize = sp - stack_start;
PRINT_VERBOSE(cfg, 1,
"bottom reached, framesize changed to %lu\n",
framesize);
}
return framesize;
}
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