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Removed artificial PATH_MAX limits. #2025

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50530c6
Removed artificial limits using PATH_MAX.
Mar 27, 2026
a2e08e4
Rewrote local char* to use std::unique_ptr.
Apr 2, 2026
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40 changes: 24 additions & 16 deletions src/tbb/cgroup_info.h
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Original file line number Diff line number Diff line change
Expand Up @@ -149,11 +149,12 @@ class cgroup_info {
}

static bool try_read_cgroup_v1_num_cpus_from(const char* dir, int& num_cpus) {
char path[PATH_MAX] = {0};
if (std::snprintf(path, PATH_MAX, "%s/cpu.cfs_quota_us", dir) < 0)
std::size_t pathlen = strlen(dir) + 30;
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@aleksei-fedotov aleksei-fedotov Apr 1, 2026

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Why +30? The longest addition is only 18 bytes, if I am not mistaken.

std::unique_ptr<char[]> path(new char[pathlen]);
if (std::snprintf(path.get(), pathlen, "%s/cpu.cfs_quota_us", dir) < 0)
return false; // Failed to create path

unique_file_t fd(std::fopen(path, "r"), &close_file);
unique_file_t fd(std::fopen(path.get(), "r"), &close_file);
if (!fd)
return false;

Expand All @@ -166,9 +167,10 @@ class cgroup_info {
return true;
}

if (std::snprintf(path, PATH_MAX, "%s/cpu.cfs_period_us", dir) < 0)
if (std::snprintf(path.get(), pathlen, "%s/cpu.cfs_period_us", dir) < 0)
return false; // Failed to create path;
fd.reset(std::fopen(path, "r"));

fd.reset(std::fopen(path.get(), "r"));
if (!fd)
return false;

Expand All @@ -181,11 +183,12 @@ class cgroup_info {
}

static bool try_read_cgroup_v2_num_cpus_from(const char* dir, int& num_cpus) {
char path[PATH_MAX] = {0};
if (std::snprintf(path, PATH_MAX, "%s/cpu.max", dir) < 0)
std::size_t pathlen = strlen(dir) + 30;
std::unique_ptr<char[]> path(new char[pathlen]);
if (std::snprintf(path.get(), pathlen, "%s/cpu.max", dir) < 0)
return false; // Failed to create path

unique_file_t fd(std::fopen(path, "r"), &close_file);
unique_file_t fd(std::fopen(path.get(), "r"), &close_file);
if (!fd)
return false;

Expand Down Expand Up @@ -222,9 +225,10 @@ class cgroup_info {

static int parse_cgroup_entry(const char* mnt_dir, process_cgroup_data& pcd) {
int num_cpus = error_value; // Initialize to an impossible value
char dir[PATH_MAX] = {0};
if (std::snprintf(dir, PATH_MAX, "%s/%s", mnt_dir, pcd.relative_path) >= 0) {
if (try_read_cgroup_num_cpus_from(dir, num_cpus, pcd.version)) {
std::size_t dirlen = strlen(mnt_dir) + strlen(pcd.relative_path) + 2;
std::unique_ptr<char[]> dir(new char[dirlen]);
if (std::snprintf(dir.get(), dirlen, "%s/%s", mnt_dir, pcd.relative_path) >= 0) {
if (try_read_cgroup_num_cpus_from(dir.get(), num_cpus, pcd.version)) {
return num_cpus;
}
}
Expand Down Expand Up @@ -276,16 +280,20 @@ class cgroup_info {
static int try_common_cgroup_mount_path(const process_cgroup_data& pcd,
const cgroup_settings& cg_cfg) {
int num_cpus = error_value;
char dir[PATH_MAX] = {0};
std::size_t dirlen = (strlen(pcd.relative_path)
+ strlen(cg_cfg.sys_fs_cgroup_dir_path)
+ 25);
std::unique_ptr<char[]> dir(new char[dirlen]);
__TBB_ASSERT(*pcd.relative_path, nullptr);
if (0 <= std::snprintf(dir, PATH_MAX, "%s/%s", cg_cfg.sys_fs_cgroup_dir_path,
if (0 <= std::snprintf(dir.get(), dirlen, "%s/%s",
cg_cfg.sys_fs_cgroup_dir_path,
pcd.relative_path))
try_read_cgroup_num_cpus_from(dir, num_cpus, pcd.version);
try_read_cgroup_num_cpus_from(dir.get(), num_cpus, pcd.version);

if (error_value == num_cpus && pcd.version == process_cgroup_data::cgroup_version::v2) {
if (0 <= std::snprintf(dir, PATH_MAX, "%s/%s", "/sys/fs/cgroup/unified",
if (0 <= std::snprintf(dir.get(), dirlen, "%s/%s", "/sys/fs/cgroup/unified",
pcd.relative_path))
try_read_cgroup_v2_num_cpus_from(dir, num_cpus);
try_read_cgroup_v2_num_cpus_from(dir.get(), num_cpus);
}
return num_cpus;
}
Expand Down
80 changes: 52 additions & 28 deletions src/tbb/dynamic_link.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -45,9 +45,6 @@
#include <wintrust.h>
#pragma comment (lib, "wintrust") // Link with the Wintrust.lib file.
#endif
#ifndef PATH_MAX
#define PATH_MAX MAX_PATH
#endif
#else /* _WIN32 */
#include <dlfcn.h>
#include <unistd.h>
Expand Down Expand Up @@ -177,7 +174,7 @@ namespace r1 {
break;
case dl_buff_too_small:
TBB_FPRINTF(stderr, "%s An internal buffer representing a path to dynamically loaded "
"module is small. Consider compiling with larger value for PATH_MAX macro.\n",
"module is small.\n",
prefix);
break;
case dl_unload_fail:
Expand Down Expand Up @@ -340,12 +337,15 @@ namespace r1 {
static std::once_flag init_dl_data_state;

static struct ap_data_t {
char _path[PATH_MAX+1];
char *_path;
std::size_t _capacity;
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@Alexandr-Konovalov Alexandr-Konovalov Apr 2, 2026

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Is _capacity really need to be saved? If I understand correctly, it only used for doubling the buffer, so probably can be lokal.

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@petterreinholdtsen petterreinholdtsen Apr 2, 2026

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I believe it is required on Windows, and for consistency I used it the same way on non-Windows platforms. I was tempted to switch also this to use std::string, but decided against it as std::string is not much used in this library.

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@Alexandr-Konovalov Alexandr-Konovalov Apr 7, 2026

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I believe it is required on Windows.

I'm not sure in that. It seems it only used to keep value of MAX_PATH and then zeroed in case of unsuccessful allocation. At which part of the code are you talking about?

std::size_t _len;
} ap_data;

static void init_ap_data() {
#if _WIN32
ap_data._capacity = MAX_PATH;
ap_data._path = (char*)calloc(ap_data._capacity, 1);
// Get handle of our DLL first.
HMODULE handle;
BOOL brc = GetModuleHandleEx(
Expand All @@ -356,30 +356,45 @@ namespace r1 {
if ( !brc ) { // Error occurred.
int err = GetLastError();
DYNAMIC_LINK_WARNING( dl_sys_fail, "GetModuleHandleEx", err );
free(ap_data._path);
ap_data._path = NULL;
ap_data._capacity = 0;
return;
}
// Now get path to our DLL.
DWORD drc = GetModuleFileName( handle, ap_data._path, static_cast< DWORD >( PATH_MAX ) );
DWORD drc = GetModuleFileName( handle, ap_data._path, static_cast< DWORD >( ap_data._capacity ) );
if ( drc == 0 ) { // Error occurred.
int err = GetLastError();
DYNAMIC_LINK_WARNING( dl_sys_fail, "GetModuleFileName", err );
free(ap_data._path);
ap_data._path = NULL;
ap_data._capacity = 0;
return;
}
if ( drc >= PATH_MAX ) { // Buffer too short.
if ( drc >= ap_data._capacity ) { // Buffer too short.
DYNAMIC_LINK_WARNING( dl_buff_too_small );
free(ap_data._path);
ap_data._path = NULL;
ap_data._capacity = 0;
return;
}
// Find the position of the last backslash.
char *backslash = std::strrchr( ap_data._path, '\\' );

if ( !backslash ) { // Backslash not found.
__TBB_ASSERT_EX( backslash != nullptr, "Unbelievable.");
free(ap_data._path);
ap_data._path = NULL;
ap_data._capacity = 0;
return;
}
__TBB_ASSERT_EX( backslash >= ap_data._path, "Unbelievable.");
ap_data._len = (std::size_t)(backslash - ap_data._path) + 1;
*(backslash+1) = 0;
#else
// Initial capacity, double until large enough
ap_data._capacity = 4096;
ap_data._path = (char*)calloc(ap_data._capacity, 1);
// There is an use case, when we want to find TBB library, not just some shared object
// providing "dynamic_link" symbol (it can be shared object that directly includes
// dynamic_link.cpp). For this case we use a public TBB symbol. Searching for public symbol
Expand All @@ -397,6 +412,9 @@ namespace r1 {
if ( !res ) {
char const * err = dlerror();
DYNAMIC_LINK_WARNING( dl_sys_fail, "dladdr", err );
free(ap_data._path);
ap_data._path = NULL;
ap_data._capacity = 0;
return;
} else {
__TBB_ASSERT_EX( dlinfo.dli_fname!=nullptr, "Unbelievable." );
Expand All @@ -416,9 +434,14 @@ namespace r1 {
ap_data._len = 0;
} else {
// The library path is relative so get the current working directory
if ( !getcwd( ap_data._path, sizeof(ap_data._path)/sizeof(ap_data._path[0]) ) ) {
DYNAMIC_LINK_WARNING( dl_buff_too_small );
return;
while ( !getcwd( ap_data._path, ap_data._capacity) ) {
free(ap_data._path);
ap_data._capacity *= 2;
ap_data._path = (char*)calloc(ap_data._capacity, 1);
if (NULL == ap_data._path) {
DYNAMIC_LINK_WARNING( dl_buff_too_small );
return;
}
}
ap_data._len = std::strlen( ap_data._path );
ap_data._path[ap_data._len++]='/';
Expand All @@ -427,9 +450,12 @@ namespace r1 {

if ( fname_len>0 ) {
ap_data._len += fname_len;
if ( ap_data._len>PATH_MAX ) {
if ( ap_data._len>ap_data._capacity ) {
DYNAMIC_LINK_WARNING( dl_buff_too_small );
ap_data._len=0;
free(ap_data._path);
ap_data._path = NULL;
ap_data._capacity = 0;
return;
}
std::strncpy( ap_data._path+rc, dlinfo.dli_fname, fname_len );
Expand Down Expand Up @@ -463,7 +489,9 @@ namespace r1 {
if ( full_len < len ) {
__TBB_ASSERT_EX( ap_data._path[ap_data._len] == 0, nullptr );
__TBB_ASSERT_EX( std::strlen(ap_data._path) == ap_data._len, nullptr );
std::strncpy( path, ap_data._path, ap_data._len + 1 );
// No need for strncpy, test above confirmed enough space
// and do not need zero padding at the end.
std::strcpy( path, ap_data._path);
__TBB_ASSERT_EX( path[ap_data._len] == 0, nullptr );
std::strncat( path, name, len - ap_data._len );
__TBB_ASSERT_EX( std::strlen(path) == full_len, nullptr );
Expand Down Expand Up @@ -662,19 +690,18 @@ namespace r1 {
* occurs, in which case the error is optionally reported.
*/
bool has_valid_signature(const char* filepath, const std::size_t length) {
__TBB_ASSERT_EX(length <= PATH_MAX, "Too small buffer for path conversion");
wchar_t wfilepath[PATH_MAX] = {0};
std::unique_ptr<wchar_t[]> wfilepath(new wchar_t[length+1]);
{
std::mbstate_t state{};
const char* ansi_filepath = filepath; // mbsrtowcs moves original pointer
const size_t num_converted = mbsrtowcs(wfilepath, &ansi_filepath, length, &state);
const size_t num_converted = mbsrtowcs(wfilepath.get(), &ansi_filepath, length, &state);
if (num_converted == std::size_t(-1))
return false;
}
WINTRUST_FILE_INFO fdata;
std::memset(&fdata, 0, sizeof(fdata));
fdata.cbStruct = sizeof(WINTRUST_FILE_INFO);
fdata.pcwszFilePath = wfilepath;
fdata.pcwszFilePath = wfilepath.get();

// Check that the certificate used to sign the specified file chains up to a root
// certificate located in the trusted root certificate store, implying that the identity of
Expand Down Expand Up @@ -710,29 +737,26 @@ namespace r1 {
dynamic_link_handle library_handle = nullptr;
#if __TBB_DYNAMIC_LOAD_ENABLED
const char* path = library;
std::size_t const len = PATH_MAX + 1;
char absolute_path[ len ] = {0};
std::size_t len = abs_path(library, NULL, 1);
std::unique_ptr<char[]> absolute_path(new char[len]);
std::size_t length = 0;
const bool build_absolute_path = flags & DYNAMIC_LINK_BUILD_ABSOLUTE_PATH;
if (build_absolute_path) {
length = abs_path( library, absolute_path, len );
if (length > len) {
DYNAMIC_LINK_WARNING( dl_buff_too_small );
return nullptr;
} else if (length == 0) {
length = abs_path( library, absolute_path.get(), len );
if (length == 0) {
// length == 0 means failing of init_ap_data so the warning has already been issued.
return nullptr;
} else if (!file_exists(absolute_path)) {
} else if (!file_exists(absolute_path.get())) {
// Path to a file has been built manually. It is not proven to exist however.
DYNAMIC_LINK_WARNING( dl_lib_not_found, absolute_path, dlerror() );
DYNAMIC_LINK_WARNING( dl_lib_not_found, absolute_path.get(), dlerror() );
return nullptr;
}
path = absolute_path;
path = absolute_path.get();
}
#if _WIN32
#if !__TBB_SKIP_DEPENDENCY_SIGNATURE_VERIFICATION
if (!build_absolute_path) { // Get the path if it is not yet built
length = get_module_path(absolute_path, len, library);
length = get_module_path(absolute_path.get(), (unsigned)len, library);
if (length == 0) {
DYNAMIC_LINK_WARNING( dl_lib_not_found, path, dlerror() );
return library_handle;
Expand All @@ -741,7 +765,7 @@ namespace r1 {
return library_handle;
}
length += 1; // Count terminating NULL character as part of string length
path = absolute_path;
path = absolute_path.get();
}

if (!has_valid_signature(path, length))
Expand Down
4 changes: 2 additions & 2 deletions src/tbb/dynamic_link.h
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@@ -1,5 +1,6 @@
/*
Copyright (c) 2005-2025 Intel Corporation
Copyright (c) 2026 UXL Foundation Contributors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
Expand Down Expand Up @@ -132,8 +133,7 @@ enum dynamic_link_error_t : int {
// System call returned error status
dl_sys_fail, // char const * func, dlerr_t err

// Internal intermediate buffer is too small, consider setting PATH_MAX
// macro to a larger value
// Internal intermediate buffer is too small
dl_buff_too_small, // none

// An error during library unload
Expand Down
3 changes: 0 additions & 3 deletions src/tbb/tools_api/ittnotify_static.c
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Expand Up @@ -20,9 +20,6 @@
#include "ittnotify_config.h"

#if ITT_PLATFORM==ITT_PLATFORM_WIN
#if !defined(PATH_MAX)
#define PATH_MAX 512
#endif
#else /* ITT_PLATFORM!=ITT_PLATFORM_WIN */
#include <limits.h>
#include <dlfcn.h>
Expand Down
29 changes: 16 additions & 13 deletions test/common/utils_concurrency_limit.h
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Expand Up @@ -207,11 +207,12 @@ class cgroup_info {
}

static bool try_read_cgroup_v1_num_cpus_from(const char* dir, int& num_cpus) {
char path[PATH_MAX] = {0};
if (std::snprintf(path, PATH_MAX, "%s/cpu.cfs_quota_us", dir) < 0)
std::size_t pathlen = strlen(dir) + 20;
std::unique_ptr<char[]> path(new char[pathlen]);
if (std::snprintf(path.get(), pathlen, "%s/cpu.cfs_quota_us", dir) < 0)
return false; // Failed to create path

unique_file_t fd(std::fopen(path, "r"), &close_file);
unique_file_t fd(std::fopen(path.get(), "r"), &close_file);
if (!fd)
return false;

Expand All @@ -224,10 +225,10 @@ class cgroup_info {
return true;
}

if (std::snprintf(path, PATH_MAX, "%s/cpu.cfs_period_us", dir) < 0)
if (std::snprintf(path.get(), pathlen, "%s/cpu.cfs_period_us", dir) < 0)
return false; // Failed to create path

fd.reset(std::fopen(path, "r"));
fd.reset(std::fopen(path.get(), "r"));
if (!fd)
return false;

Expand All @@ -240,11 +241,12 @@ class cgroup_info {
}

static bool try_read_cgroup_v2_num_cpus_from(const char* dir, int& num_cpus) {
char path[PATH_MAX] = {0};
if (std::snprintf(path, PATH_MAX, "%s/cpu.max", dir) < 0)
std::size_t pathlen = strlen(dir) + 10;
std::unique_ptr<char[]> path(new char[pathlen]);
if (std::snprintf(path.get(), pathlen, "%s/cpu.max", dir) < 0)
return false;

unique_file_t fd(std::fopen(path, "r"), &close_file);
unique_file_t fd(std::fopen(path.get(), "r"), &close_file);
if (!fd)
return false;

Expand Down Expand Up @@ -272,7 +274,8 @@ class cgroup_info {
cgroup_paths& paths_cache)
{
int num_cpus = error_value; // Initialize to an impossible value
char dir[PATH_MAX] = {0};
std::size_t dirlen = strlen(mnt_dir) + rel_path_size + 2;
std::unique_ptr<char[]> dir(new char[dirlen]);
if (!std::strncmp(mnt_type, "cgroup2", 7)) { // Found cgroup v2 mount entry
// At first, try reading CPU quota directly
if (try_read_cgroup_v2_num_cpus_from(mnt_dir, num_cpus))
Expand All @@ -282,8 +285,8 @@ class cgroup_info {
cache_relative_path_for(cgroup_fd, paths_cache);

// Now try reading including relative path
if (std::snprintf(dir, PATH_MAX, "%s/%s", mnt_dir, paths_cache.v2_relative_path) >= 0)
try_read_cgroup_v2_num_cpus_from(dir, num_cpus);
if (std::snprintf(dir.get(), dirlen, "%s/%s", mnt_dir, paths_cache.v2_relative_path) >= 0)
try_read_cgroup_v2_num_cpus_from(dir.get(), num_cpus);
return num_cpus;
}

Expand All @@ -295,8 +298,8 @@ class cgroup_info {
if (!*paths_cache.v1_relative_path)
cache_relative_path_for(cgroup_fd, paths_cache);

if (std::snprintf(dir, PATH_MAX, "%s/%s", mnt_dir, paths_cache.v1_relative_path) >= 0)
try_read_cgroup_v1_num_cpus_from(dir, num_cpus);
if (std::snprintf(dir.get(), dirlen, "%s/%s", mnt_dir, paths_cache.v1_relative_path) >= 0)
try_read_cgroup_v1_num_cpus_from(dir.get(), num_cpus);
return num_cpus;
}

Expand Down
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