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#include <dlfcn.h> /* dladdr */
#include <stddef.h> /* NULL */
#include <stdint.h> /* uintptr_t */
#include <stdlib.h> /* calloc */
#include <string.h> /* strlen */
#include <unistd.h> /* write */
#define get_frame_level(array, size, n) \
do { \
if (n >= size || __builtin_frame_address(n) == NULL) { \
return n; \
} \
void *address = __builtin_return_address(n); \
array[n] = __builtin_extract_return_addr(address); \
if ((uintptr_t) array[n] < 0x1000) { \
return n; \
} \
} while (0)
/**
* Obtain a backtrace for the calling program.
*
* LSB 5.0: LSB-Core-generic/baselib-backtrace-1.html
*/
int backtrace(void **array, int size)
{
get_frame_level(array, size, 0);
get_frame_level(array, size, 1);
get_frame_level(array, size, 2);
get_frame_level(array, size, 3);
get_frame_level(array, size, 4);
get_frame_level(array, size, 5);
get_frame_level(array, size, 6);
get_frame_level(array, size, 7);
get_frame_level(array, size, 8);
get_frame_level(array, size, 9);
return 10;
}
/**
* Translate addresses into symbol information.
*
* LSB 5.0: LSB-Core-generic/baselib-backtrace-1.html
*/
const char **backtrace_symbols(void *const *array, int size)
{
const char **result = calloc(size, sizeof(char *));
if (result == NULL) {
return NULL;
}
for (int i = 0; i < size; ++i) {
Dl_info info;
if (dladdr(array[i], &info) && info.dli_sname != NULL) {
result[i] = info.dli_sname;
} else {
result[i] = "??:0";
}
}
return result;
}
/**
* Write symbol information to a file without allocating memory.
*
* LSB 5.0: LSB-Core-generic/baselib-backtrace-1.html
*/
void backtrace_symbols_fd(void *const *array, int size, int fd)
{
for (int i = 0; i < size; ++i) {
Dl_info info;
const char *line;
int len;
if (dladdr(array[i], &info) && info.dli_sname != NULL) {
line = info.dli_sname;
len = strlen(line);
} else {
line = "??:0";
len = sizeof("??:0") - 1;
}
while (len > 0) {
int written = write(fd, line, len);
if (written < 1) {
return;
}
line += written;
len -= written;
}
if (write(fd, "\n", 1) != 1) {
return;
}
}
}
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