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gh-103295: expose API for writing perf map files (#103546)

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Co-authored-by: Aniket Panse <aniketpanse@fb.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>
Co-authored-by: Carl Meyer <carl@oddbird.net>
This commit is contained in:
gsallam 2023-05-21 03:12:24 -07:00 • committed by GitHub
parent 2e91c7e626
commit be0c106789
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GPG key ID: 4AEE18F83AFDEB23
11 changed files with 214 additions and 73 deletions
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86
Python/perf_trampoline.c
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@ -193,75 +193,33 @@ typedef struct trampoline_api_st trampoline_api_t;
#define trampoline_api _PyRuntime.ceval.perf.trampoline_api
#define perf_map_file _PyRuntime.ceval.perf.map_file
static void *
perf_map_get_file(void)
{
if (perf_map_file) {
return perf_map_file;
}
char filename[100];
pid_t pid = getpid();
// Location and file name of perf map is hard-coded in perf tool.
// Use exclusive create flag wit nofollow to prevent symlink attacks.
int flags = O_WRONLY | O_CREAT | O_EXCL | O_NOFOLLOW | O_CLOEXEC;
snprintf(filename, sizeof(filename) - 1, "/tmp/perf-%jd.map",
(intmax_t)pid);
int fd = open(filename, flags, 0600);
if (fd == -1) {
perf_status = PERF_STATUS_FAILED;
PyErr_SetFromErrnoWithFilename(PyExc_OSError, filename);
return NULL;
}
perf_map_file = fdopen(fd, "w");
if (!perf_map_file) {
perf_status = PERF_STATUS_FAILED;
PyErr_SetFromErrnoWithFilename(PyExc_OSError, filename);
close(fd);
return NULL;
}
return perf_map_file;
}
static int
perf_map_close(void *state)
{
FILE *fp = (FILE *)state;
int ret = 0;
if (fp) {
ret = fclose(fp);
}
perf_map_file = NULL;
perf_status = PERF_STATUS_NO_INIT;
return ret;
}
static void
perf_map_write_entry(void *state, const void *code_addr,
unsigned int code_size, PyCodeObject *co)
{
assert(state != NULL);
FILE *method_file = (FILE *)state;
const char *entry = PyUnicode_AsUTF8(co->co_qualname);
if (entry == NULL) {
_PyErr_WriteUnraisableMsg("Failed to get qualname from code object",
NULL);
const char *entry = "";
if (co->co_qualname != NULL) {
entry = PyUnicode_AsUTF8(co->co_qualname);
}
const char *filename = "";
if (co->co_filename != NULL) {
filename = PyUnicode_AsUTF8(co->co_filename);
}
size_t perf_map_entry_size = snprintf(NULL, 0, "py::%s:%s", entry, filename) + 1;
char* perf_map_entry = (char*) PyMem_RawMalloc(perf_map_entry_size);
if (perf_map_entry == NULL) {
return;
}
const char *filename = PyUnicode_AsUTF8(co->co_filename);
if (filename == NULL) {
_PyErr_WriteUnraisableMsg("Failed to get filename from code object",
NULL);
return;
}
fprintf(method_file, "%" PRIxPTR " %x py::%s:%s\n", (uintptr_t) code_addr, code_size, entry,
filename);
fflush(method_file);
snprintf(perf_map_entry, perf_map_entry_size, "py::%s:%s", entry, filename);
PyUnstable_WritePerfMapEntry(code_addr, code_size, perf_map_entry);
PyMem_RawFree(perf_map_entry);
}
_PyPerf_Callbacks _Py_perfmap_callbacks = {
&perf_map_get_file,
NULL,
&perf_map_write_entry,
&perf_map_close
NULL,
};
static int
@ -465,13 +423,6 @@ _PyPerfTrampoline_Init(int activate)
if (new_code_arena() < 0) {
return -1;
}
if (trampoline_api.state == NULL) {
void *state = trampoline_api.init_state();
if (state == NULL) {
return -1;
}
trampoline_api.state = state;
}
extra_code_index = _PyEval_RequestCodeExtraIndex(NULL);
if (extra_code_index == -1) {
return -1;
@ -491,10 +442,6 @@ _PyPerfTrampoline_Fini(void)
tstate->interp->eval_frame = NULL;
}
free_code_arenas();
if (trampoline_api.state != NULL) {
trampoline_api.free_state(trampoline_api.state);
trampoline_api.state = NULL;
}
extra_code_index = -1;
#endif
return 0;
@ -507,6 +454,7 @@ _PyPerfTrampoline_AfterFork_Child(void)
// Restart trampoline in file in child.
int was_active = _PyIsPerfTrampolineActive();
_PyPerfTrampoline_Fini();
PyUnstable_PerfMapState_Fini();
if (was_active) {
_PyPerfTrampoline_Init(1);
}