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/* -*- linux-c -*-
* Unwind data functions for staprun.
*
* Copyright (C) 2008 Red Hat Inc.
*
* 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.
*/
#include "staprun.h"
#include <elfutils/libdwfl.h>
#include <dwarf.h>
static char debuginfo_path_arr[] = "-:.debug:/usr/lib/debug";
static char *debuginfo_path = debuginfo_path_arr;
static const Dwfl_Callbacks kernel_callbacks = {
.find_debuginfo = dwfl_standard_find_debuginfo,
.debuginfo_path = &debuginfo_path,
.find_elf = dwfl_linux_kernel_find_elf,
.section_address = dwfl_linux_kernel_module_section_address,
};
void *get_module_unwind_data(Dwfl * dwfl, const char *name, int *len)
{
Dwarf_Addr bias = 0;
Dwarf *dw;
GElf_Ehdr *ehdr, ehdr_mem;
GElf_Shdr *shdr, shdr_mem;
Elf_Scn *scn = NULL;
Elf_Data *data = NULL;
Dwfl_Module *mod = dwfl_report_module(dwfl, name, 0, 0);
dwfl_report_end(dwfl, NULL, NULL);
dw = dwfl_module_getdwarf(mod, &bias);
Elf *elf = dwarf_getelf(dw);
ehdr = gelf_getehdr(elf, &ehdr_mem);
while ((scn = elf_nextscn(elf, scn))) {
shdr = gelf_getshdr(scn, &shdr_mem);
if (strcmp(elf_strptr(elf, ehdr->e_shstrndx, shdr->sh_name), ".debug_frame") == 0) {
data = elf_rawdata(scn, NULL);
break;
}
}
if (data == NULL) {
*len = 0;
dbug(2, "module %s returns NULL\n", name);
return NULL;
}
dbug(2, "module %s returns %d\n", name, (int)data->d_size);
*len = data->d_size;
return data->d_buf;
}
void send_unwind_data(const char *name)
{
struct _stp_msg_unwind *un;
int unwind_data_len = 0;
void *unwind_data = NULL;
char *buf;
dbug(2, "module %s\n", name);
if (strcmp(name, "*")) {
Dwfl *dwfl = dwfl_begin(&kernel_callbacks);
if (name[0] == 0)
unwind_data = get_module_unwind_data(dwfl, "kernel", &unwind_data_len);
else
unwind_data = get_module_unwind_data(dwfl, name, &unwind_data_len);
/* yuck */
buf = (char *)malloc(unwind_data_len + sizeof(*un) + sizeof(uint32_t));
if (!buf) {
err("malloc failed\n");
return;
}
memcpy(buf + sizeof(*un) + sizeof(uint32_t), unwind_data, unwind_data_len);
dwfl_end(dwfl);
} else {
buf = (char *)malloc(sizeof(*un) + sizeof(uint32_t));
if (!buf) {
err("malloc failed\n");
return;
}
}
un = (struct _stp_msg_unwind *)(buf + sizeof(uint32_t));
strncpy(un->name, name, sizeof(un->name));
un->unwind_len = unwind_data_len;
*(uint32_t *) buf = STP_UNWIND;
/* send unwind data */
if (write(control_channel, buf, unwind_data_len + sizeof(*un) + sizeof(uint32_t)) <= 0)
err("write failed\n");
}
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