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esp-idf/components/vfs/vfs.c
David Cermak bf8ceae780 vfs: Fix potential select() race if both sock and other-fd trigger 
This fixes a potential race condition in select() if both a socket-fd
and non-socket fd trigger simultaneously to unblock this select.
In case of both fds, we use lwip's local thread semaphore, so we only
have to try return it (if it was taken/triggered more than once) when
we exit select().

Closes https://github.com/espressif/esp-idf/issues/8896
2022-05-16 20:26:44 +02:00

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/*
* SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <sys/errno.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <sys/reent.h>
#include <sys/unistd.h>
#include <sys/lock.h>
#include <sys/param.h>
#include <dirent.h>
#include "freertos/FreeRTOS.h"
#include "freertos/semphr.h"
#include "esp_vfs.h"
#include "esp_vfs_private.h"
#include "sdkconfig.h"
// Warn about using deprecated option
#ifdef CONFIG_LWIP_USE_ONLY_LWIP_SELECT
#warning CONFIG_LWIP_USE_ONLY_LWIP_SELECT is deprecated: Please use CONFIG_VFS_SUPPORT_SELECT instead
#endif
#ifdef CONFIG_VFS_SUPPRESS_SELECT_DEBUG_OUTPUT
#define LOG_LOCAL_LEVEL ESP_LOG_NONE
#endif //CONFIG_VFS_SUPPRESS_SELECT_DEBUG_OUTPUT
#include "esp_log.h"
static const char *TAG = "vfs";
#define VFS_MAX_COUNT 8 /* max number of VFS entries (registered filesystems) */
#define LEN_PATH_PREFIX_IGNORED SIZE_MAX /* special length value for VFS which is never recognised by open() */
#define FD_TABLE_ENTRY_UNUSED (fd_table_t) { .permanent = false, .has_pending_close = false, .has_pending_select = false, .vfs_index = -1, .local_fd = -1 }
typedef uint8_t local_fd_t;
_Static_assert((1 << (sizeof(local_fd_t)*8)) >= MAX_FDS, "file descriptor type too small");
typedef int8_t vfs_index_t;
_Static_assert((1 << (sizeof(vfs_index_t)*8)) >= VFS_MAX_COUNT, "VFS index type too small");
_Static_assert(((vfs_index_t) -1) < 0, "vfs_index_t must be a signed type");
typedef struct {
bool permanent :1;
bool has_pending_close :1;
bool has_pending_select :1;
uint8_t _reserved :5;
vfs_index_t vfs_index;
local_fd_t local_fd;
} fd_table_t;
typedef struct {
bool isset; // none or at least one bit is set in the following 3 fd sets
fd_set readfds;
fd_set writefds;
fd_set errorfds;
} fds_triple_t;
static vfs_entry_t* s_vfs[VFS_MAX_COUNT] = { 0 };
static size_t s_vfs_count = 0;
static fd_table_t s_fd_table[MAX_FDS] = { [0 ... MAX_FDS-1] = FD_TABLE_ENTRY_UNUSED };
static _lock_t s_fd_table_lock;
esp_err_t esp_vfs_register_common(const char* base_path, size_t len, const esp_vfs_t* vfs, void* ctx, int *vfs_index)
{
if (len != LEN_PATH_PREFIX_IGNORED) {
/* empty prefix is allowed, "/" is not allowed */
if ((len == 1) || (len > ESP_VFS_PATH_MAX)) {
return ESP_ERR_INVALID_ARG;
}
/* prefix has to start with "/" and not end with "/" */
if (len >= 2 && ((base_path[0] != '/') || (base_path[len - 1] == '/'))) {
return ESP_ERR_INVALID_ARG;
}
}
vfs_entry_t *entry = (vfs_entry_t*) malloc(sizeof(vfs_entry_t));
if (entry == NULL) {
return ESP_ERR_NO_MEM;
}
size_t index;
for (index = 0; index < s_vfs_count; ++index) {
if (s_vfs[index] == NULL) {
break;
}
}
if (index == s_vfs_count) {
if (s_vfs_count >= VFS_MAX_COUNT) {
free(entry);
return ESP_ERR_NO_MEM;
}
++s_vfs_count;
}
s_vfs[index] = entry;
if (len != LEN_PATH_PREFIX_IGNORED) {
strcpy(entry->path_prefix, base_path); // we have already verified argument length
} else {
bzero(entry->path_prefix, sizeof(entry->path_prefix));
}
memcpy(&entry->vfs, vfs, sizeof(esp_vfs_t));
entry->path_prefix_len = len;
entry->ctx = ctx;
entry->offset = index;
if (vfs_index) {
*vfs_index = index;
}
return ESP_OK;
}
esp_err_t esp_vfs_register(const char* base_path, const esp_vfs_t* vfs, void* ctx)
{
return esp_vfs_register_common(base_path, strlen(base_path), vfs, ctx, NULL);
}
esp_err_t esp_vfs_register_fd_range(const esp_vfs_t *vfs, void *ctx, int min_fd, int max_fd)
{
if (min_fd < 0 || max_fd < 0 || min_fd > MAX_FDS || max_fd > MAX_FDS || min_fd > max_fd) {
ESP_LOGD(TAG, "Invalid arguments: esp_vfs_register_fd_range(0x%x, 0x%x, %d, %d)", (int) vfs, (int) ctx, min_fd, max_fd);
return ESP_ERR_INVALID_ARG;
}
int index = -1;
esp_err_t ret = esp_vfs_register_common("", LEN_PATH_PREFIX_IGNORED, vfs, ctx, &index);
if (ret == ESP_OK) {
_lock_acquire(&s_fd_table_lock);
for (int i = min_fd; i < max_fd; ++i) {
if (s_fd_table[i].vfs_index != -1) {
free(s_vfs[index]);
s_vfs[index] = NULL;
for (int j = min_fd; j < i; ++j) {
if (s_fd_table[j].vfs_index == index) {
s_fd_table[j] = FD_TABLE_ENTRY_UNUSED;
}
}
_lock_release(&s_fd_table_lock);
ESP_LOGD(TAG, "esp_vfs_register_fd_range cannot set fd %d (used by other VFS)", i);
return ESP_ERR_INVALID_ARG;
}
s_fd_table[i].permanent = true;
s_fd_table[i].vfs_index = index;
s_fd_table[i].local_fd = i;
}
_lock_release(&s_fd_table_lock);
ESP_LOGW(TAG, "esp_vfs_register_fd_range is successful for range <%d; %d) and VFS ID %d", min_fd, max_fd, index);
}
return ret;
}
esp_err_t esp_vfs_register_with_id(const esp_vfs_t *vfs, void *ctx, esp_vfs_id_t *vfs_id)
{
if (vfs_id == NULL) {
return ESP_ERR_INVALID_ARG;
}
*vfs_id = -1;
return esp_vfs_register_common("", LEN_PATH_PREFIX_IGNORED, vfs, ctx, vfs_id);
}
esp_err_t esp_vfs_unregister_with_id(esp_vfs_id_t vfs_id)
{
if (vfs_id < 0 || vfs_id >= VFS_MAX_COUNT || s_vfs[vfs_id] == NULL) {
return ESP_ERR_INVALID_ARG;
}
vfs_entry_t* vfs = s_vfs[vfs_id];
free(vfs);
s_vfs[vfs_id] = NULL;
_lock_acquire(&s_fd_table_lock);
// Delete all references from the FD lookup-table
for (int j = 0; j < VFS_MAX_COUNT; ++j) {
if (s_fd_table[j].vfs_index == vfs_id) {
s_fd_table[j] = FD_TABLE_ENTRY_UNUSED;
}
}
_lock_release(&s_fd_table_lock);
return ESP_OK;
}
esp_err_t esp_vfs_unregister(const char* base_path)
{
const size_t base_path_len = strlen(base_path);
for (size_t i = 0; i < s_vfs_count; ++i) {
vfs_entry_t* vfs = s_vfs[i];
if (vfs == NULL) {
continue;
}
if (base_path_len == vfs->path_prefix_len &&
memcmp(base_path, vfs->path_prefix, vfs->path_prefix_len) == 0) {
return esp_vfs_unregister_with_id(i);
}
}
return ESP_ERR_INVALID_STATE;
}
esp_err_t esp_vfs_register_fd(esp_vfs_id_t vfs_id, int *fd)
{
return esp_vfs_register_fd_with_local_fd(vfs_id, -1, true, fd);
}
esp_err_t esp_vfs_register_fd_with_local_fd(esp_vfs_id_t vfs_id, int local_fd, bool permanent, int *fd)
{
if (vfs_id < 0 || vfs_id >= s_vfs_count || fd == NULL) {
ESP_LOGD(TAG, "Invalid arguments for esp_vfs_register_fd_with_local_fd(%d, %d, %d, 0x%p)",
vfs_id, local_fd, permanent, fd);
return ESP_ERR_INVALID_ARG;
}
esp_err_t ret = ESP_ERR_NO_MEM;
_lock_acquire(&s_fd_table_lock);
for (int i = 0; i < MAX_FDS; ++i) {
if (s_fd_table[i].vfs_index == -1) {
s_fd_table[i].permanent = permanent;
s_fd_table[i].vfs_index = vfs_id;
if (local_fd >= 0) {
s_fd_table[i].local_fd = local_fd;
} else {
s_fd_table[i].local_fd = i;
}
*fd = i;
ret = ESP_OK;
break;
}
}
_lock_release(&s_fd_table_lock);
ESP_LOGD(TAG, "esp_vfs_register_fd_with_local_fd(%d, %d, %d, 0x%p) finished with %s",
vfs_id, local_fd, permanent, fd, esp_err_to_name(ret));
return ret;
}
esp_err_t esp_vfs_unregister_fd(esp_vfs_id_t vfs_id, int fd)
{
esp_err_t ret = ESP_ERR_INVALID_ARG;
if (vfs_id < 0 || vfs_id >= s_vfs_count || fd < 0 || fd >= MAX_FDS) {
ESP_LOGD(TAG, "Invalid arguments for esp_vfs_unregister_fd(%d, %d)", vfs_id, fd);
return ret;
}
_lock_acquire(&s_fd_table_lock);
fd_table_t *item = s_fd_table + fd;
if (item->permanent == true && item->vfs_index == vfs_id && item->local_fd == fd) {
*item = FD_TABLE_ENTRY_UNUSED;
ret = ESP_OK;
}
_lock_release(&s_fd_table_lock);
ESP_LOGD(TAG, "esp_vfs_unregister_fd(%d, %d) finished with %s", vfs_id, fd, esp_err_to_name(ret));
return ret;
}
const vfs_entry_t *get_vfs_for_index(int index)
{
if (index < 0 || index >= s_vfs_count) {
return NULL;
} else {
return s_vfs[index];
}
}
static inline bool fd_valid(int fd)
{
return (fd < MAX_FDS) && (fd >= 0);
}
static const vfs_entry_t *get_vfs_for_fd(int fd)
{
const vfs_entry_t *vfs = NULL;
if (fd_valid(fd)) {
const int index = s_fd_table[fd].vfs_index; // single read -> no locking is required
vfs = get_vfs_for_index(index);
}
return vfs;
}
static inline int get_local_fd(const vfs_entry_t *vfs, int fd)
{
int local_fd = -1;
if (vfs && fd_valid(fd)) {
local_fd = s_fd_table[fd].local_fd; // single read -> no locking is required
}
return local_fd;
}
static const char* translate_path(const vfs_entry_t* vfs, const char* src_path)
{
assert(strncmp(src_path, vfs->path_prefix, vfs->path_prefix_len) == 0);
if (strlen(src_path) == vfs->path_prefix_len) {
// special case when src_path matches the path prefix exactly
return "/";
}
return src_path + vfs->path_prefix_len;
}
const vfs_entry_t* get_vfs_for_path(const char* path)
{
const vfs_entry_t* best_match = NULL;
ssize_t best_match_prefix_len = -1;
size_t len = strlen(path);
for (size_t i = 0; i < s_vfs_count; ++i) {
const vfs_entry_t* vfs = s_vfs[i];
if (!vfs || vfs->path_prefix_len == LEN_PATH_PREFIX_IGNORED) {
continue;
}
// match path prefix
if (len < vfs->path_prefix_len ||
memcmp(path, vfs->path_prefix, vfs->path_prefix_len) != 0) {
continue;
}
// this is the default VFS and we don't have a better match yet.
if (vfs->path_prefix_len == 0 && !best_match) {
best_match = vfs;
continue;
}
// if path is not equal to the prefix, expect to see a path separator
// i.e. don't match "/data" prefix for "/data1/foo.txt" path
if (len > vfs->path_prefix_len &&
path[vfs->path_prefix_len] != '/') {
continue;
}
// Out of all matching path prefixes, select the longest one;
// i.e. if "/dev" and "/dev/uart" both match, for "/dev/uart/1" path,
// choose "/dev/uart",
// This causes all s_vfs_count VFS entries to be scanned when opening
// a file by name. This can be optimized by introducing a table for
// FS search order, sorted so that longer prefixes are checked first.
if (best_match_prefix_len < (ssize_t) vfs->path_prefix_len) {
best_match_prefix_len = (ssize_t) vfs->path_prefix_len;
best_match = vfs;
}
}
return best_match;
}
/*
* Using huge multi-line macros is never nice, but in this case
* the only alternative is to repeat this chunk of code (with different function names)
* for each syscall being implemented. Given that this define is contained within a single
* file, this looks like a good tradeoff.
*
* First we check if syscall is implemented by VFS (corresponding member is not NULL),
* then call the right flavor of the method (e.g. open or open_p) depending on
* ESP_VFS_FLAG_CONTEXT_PTR flag. If ESP_VFS_FLAG_CONTEXT_PTR is set, context is passed
* in as first argument and _p variant is used for the call.
* It is enough to check just one of them for NULL, as both variants are part of a union.
*/
#define CHECK_AND_CALL(ret, r, pvfs, func, ...) \
if (pvfs->vfs.func == NULL) { \
__errno_r(r) = ENOSYS; \
return -1; \
} \
if (pvfs->vfs.flags & ESP_VFS_FLAG_CONTEXT_PTR) { \
ret = (*pvfs->vfs.func ## _p)(pvfs->ctx, __VA_ARGS__); \
} else { \
ret = (*pvfs->vfs.func)(__VA_ARGS__);\
}
#define CHECK_AND_CALLV(r, pvfs, func, ...) \
if (pvfs->vfs.func == NULL) { \
__errno_r(r) = ENOSYS; \
return; \
} \
if (pvfs->vfs.flags & ESP_VFS_FLAG_CONTEXT_PTR) { \
(*pvfs->vfs.func ## _p)(pvfs->ctx, __VA_ARGS__); \
} else { \
(*pvfs->vfs.func)(__VA_ARGS__);\
}
#define CHECK_AND_CALLP(ret, r, pvfs, func, ...) \
if (pvfs->vfs.func == NULL) { \
__errno_r(r) = ENOSYS; \
return NULL; \
} \
if (pvfs->vfs.flags & ESP_VFS_FLAG_CONTEXT_PTR) { \
ret = (*pvfs->vfs.func ## _p)(pvfs->ctx, __VA_ARGS__); \
} else { \
ret = (*pvfs->vfs.func)(__VA_ARGS__);\
}
int esp_vfs_open(struct _reent *r, const char * path, int flags, int mode)
{
const vfs_entry_t *vfs = get_vfs_for_path(path);
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const char *path_within_vfs = translate_path(vfs, path);
int fd_within_vfs;
CHECK_AND_CALL(fd_within_vfs, r, vfs, open, path_within_vfs, flags, mode);
if (fd_within_vfs >= 0) {
_lock_acquire(&s_fd_table_lock);
for (int i = 0; i < MAX_FDS; ++i) {
if (s_fd_table[i].vfs_index == -1) {
s_fd_table[i].permanent = false;
s_fd_table[i].vfs_index = vfs->offset;
s_fd_table[i].local_fd = fd_within_vfs;
_lock_release(&s_fd_table_lock);
return i;
}
}
_lock_release(&s_fd_table_lock);
int ret;
CHECK_AND_CALL(ret, r, vfs, close, fd_within_vfs);
(void) ret; // remove "set but not used" warning
__errno_r(r) = ENOMEM;
return -1;
}
__errno_r(r) = errno;
return -1;
}
ssize_t esp_vfs_write(struct _reent *r, int fd, const void * data, size_t size)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
ssize_t ret;
CHECK_AND_CALL(ret, r, vfs, write, local_fd, data, size);
return ret;
}
off_t esp_vfs_lseek(struct _reent *r, int fd, off_t size, int mode)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
off_t ret;
CHECK_AND_CALL(ret, r, vfs, lseek, local_fd, size, mode);
return ret;
}
ssize_t esp_vfs_read(struct _reent *r, int fd, void * dst, size_t size)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
ssize_t ret;
CHECK_AND_CALL(ret, r, vfs, read, local_fd, dst, size);
return ret;
}
ssize_t esp_vfs_pread(int fd, void *dst, size_t size, off_t offset)
{
struct _reent *r = __getreent();
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
ssize_t ret;
CHECK_AND_CALL(ret, r, vfs, pread, local_fd, dst, size, offset);
return ret;
}
ssize_t esp_vfs_pwrite(int fd, const void *src, size_t size, off_t offset)
{
struct _reent *r = __getreent();
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
ssize_t ret;
CHECK_AND_CALL(ret, r, vfs, pwrite, local_fd, src, size, offset);
return ret;
}
int esp_vfs_close(struct _reent *r, int fd)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, close, local_fd);
_lock_acquire(&s_fd_table_lock);
if (!s_fd_table[fd].permanent) {
if (s_fd_table[fd].has_pending_select) {
s_fd_table[fd].has_pending_close = true;
} else {
s_fd_table[fd] = FD_TABLE_ENTRY_UNUSED;
}
}
_lock_release(&s_fd_table_lock);
return ret;
}
int esp_vfs_fstat(struct _reent *r, int fd, struct stat * st)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, fstat, local_fd, st);
return ret;
}
int esp_vfs_fcntl_r(struct _reent *r, int fd, int cmd, int arg)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, fcntl, local_fd, cmd, arg);
return ret;
}
int esp_vfs_ioctl(int fd, int cmd, ...)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
va_list args;
va_start(args, cmd);
CHECK_AND_CALL(ret, r, vfs, ioctl, local_fd, cmd, args);
va_end(args);
return ret;
}
int esp_vfs_fsync(int fd)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, fsync, local_fd);
return ret;
}
#ifdef CONFIG_VFS_SUPPORT_DIR
int esp_vfs_stat(struct _reent *r, const char * path, struct stat * st)
{
const vfs_entry_t* vfs = get_vfs_for_path(path);
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const char* path_within_vfs = translate_path(vfs, path);
int ret;
CHECK_AND_CALL(ret, r, vfs, stat, path_within_vfs, st);
return ret;
}
int esp_vfs_utime(const char *path, const struct utimbuf *times)
{
int ret;
const vfs_entry_t* vfs = get_vfs_for_path(path);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const char* path_within_vfs = translate_path(vfs, path);
CHECK_AND_CALL(ret, r, vfs, utime, path_within_vfs, times);
return ret;
}
int esp_vfs_link(struct _reent *r, const char* n1, const char* n2)
{
const vfs_entry_t* vfs = get_vfs_for_path(n1);
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const vfs_entry_t* vfs2 = get_vfs_for_path(n2);
if (vfs != vfs2) {
__errno_r(r) = EXDEV;
return -1;
}
const char* path1_within_vfs = translate_path(vfs, n1);
const char* path2_within_vfs = translate_path(vfs, n2);
int ret;
CHECK_AND_CALL(ret, r, vfs, link, path1_within_vfs, path2_within_vfs);
return ret;
}
int esp_vfs_unlink(struct _reent *r, const char *path)
{
const vfs_entry_t* vfs = get_vfs_for_path(path);
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const char* path_within_vfs = translate_path(vfs, path);
int ret;
CHECK_AND_CALL(ret, r, vfs, unlink, path_within_vfs);
return ret;
}
int esp_vfs_rename(struct _reent *r, const char *src, const char *dst)
{
const vfs_entry_t* vfs = get_vfs_for_path(src);
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const vfs_entry_t* vfs_dst = get_vfs_for_path(dst);
if (vfs != vfs_dst) {
__errno_r(r) = EXDEV;
return -1;
}
const char* src_within_vfs = translate_path(vfs, src);
const char* dst_within_vfs = translate_path(vfs, dst);
int ret;
CHECK_AND_CALL(ret, r, vfs, rename, src_within_vfs, dst_within_vfs);
return ret;
}
DIR* esp_vfs_opendir(const char* name)
{
const vfs_entry_t* vfs = get_vfs_for_path(name);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return NULL;
}
const char* path_within_vfs = translate_path(vfs, name);
DIR* ret;
CHECK_AND_CALLP(ret, r, vfs, opendir, path_within_vfs);
if (ret != NULL) {
ret->dd_vfs_idx = vfs->offset;
}
return ret;
}
struct dirent* esp_vfs_readdir(DIR* pdir)
{
const vfs_entry_t* vfs = get_vfs_for_index(pdir->dd_vfs_idx);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = EBADF;
return NULL;
}
struct dirent* ret;
CHECK_AND_CALLP(ret, r, vfs, readdir, pdir);
return ret;
}
int esp_vfs_readdir_r(DIR* pdir, struct dirent* entry, struct dirent** out_dirent)
{
const vfs_entry_t* vfs = get_vfs_for_index(pdir->dd_vfs_idx);
struct _reent* r = __getreent();
if (vfs == NULL) {
errno = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, readdir_r, pdir, entry, out_dirent);
return ret;
}
long esp_vfs_telldir(DIR* pdir)
{
const vfs_entry_t* vfs = get_vfs_for_index(pdir->dd_vfs_idx);
struct _reent* r = __getreent();
if (vfs == NULL) {
errno = EBADF;
return -1;
}
long ret;
CHECK_AND_CALL(ret, r, vfs, telldir, pdir);
return ret;
}
void esp_vfs_seekdir(DIR* pdir, long loc)
{
const vfs_entry_t* vfs = get_vfs_for_index(pdir->dd_vfs_idx);
struct _reent* r = __getreent();
if (vfs == NULL) {
errno = EBADF;
return;
}
CHECK_AND_CALLV(r, vfs, seekdir, pdir, loc);
}
void esp_vfs_rewinddir(DIR* pdir)
{
seekdir(pdir, 0);
}
int esp_vfs_closedir(DIR* pdir)
{
const vfs_entry_t* vfs = get_vfs_for_index(pdir->dd_vfs_idx);
struct _reent* r = __getreent();
if (vfs == NULL) {
errno = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, closedir, pdir);
return ret;
}
int esp_vfs_mkdir(const char* name, mode_t mode)
{
const vfs_entry_t* vfs = get_vfs_for_path(name);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const char* path_within_vfs = translate_path(vfs, name);
int ret;
CHECK_AND_CALL(ret, r, vfs, mkdir, path_within_vfs, mode);
return ret;
}
int esp_vfs_rmdir(const char* name)
{
const vfs_entry_t* vfs = get_vfs_for_path(name);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const char* path_within_vfs = translate_path(vfs, name);
int ret;
CHECK_AND_CALL(ret, r, vfs, rmdir, path_within_vfs);
return ret;
}
int esp_vfs_access(const char *path, int amode)
{
int ret;
const vfs_entry_t* vfs = get_vfs_for_path(path);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const char* path_within_vfs = translate_path(vfs, path);
CHECK_AND_CALL(ret, r, vfs, access, path_within_vfs, amode);
return ret;
}
int esp_vfs_truncate(const char *path, off_t length)
{
int ret;
const vfs_entry_t* vfs = get_vfs_for_path(path);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
const char* path_within_vfs = translate_path(vfs, path);
CHECK_AND_CALL(ret, r, vfs, truncate, path_within_vfs, length);
return ret;
}
int esp_vfs_ftruncate(int fd, off_t length)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, ftruncate, local_fd, length);
return ret;
}
#endif // CONFIG_VFS_SUPPORT_DIR
#ifdef CONFIG_VFS_SUPPORT_SELECT
static void call_end_selects(int end_index, const fds_triple_t *vfs_fds_triple, void **driver_args)
{
for (int i = 0; i < end_index; ++i) {
const vfs_entry_t *vfs = get_vfs_for_index(i);
const fds_triple_t *item = &vfs_fds_triple[i];
if (vfs && vfs->vfs.end_select && item->isset) {
esp_err_t err = vfs->vfs.end_select(driver_args[i]);
if (err != ESP_OK) {
ESP_LOGD(TAG, "end_select failed: %s", esp_err_to_name(err));
}
}
}
}
static inline bool esp_vfs_safe_fd_isset(int fd, const fd_set *fds)
{
return fds && FD_ISSET(fd, fds);
}
static int set_global_fd_sets(const fds_triple_t *vfs_fds_triple, int size, fd_set *readfds, fd_set *writefds, fd_set *errorfds)
{
int ret = 0;
for (int i = 0; i < size; ++i) {
const fds_triple_t *item = &vfs_fds_triple[i];
if (item->isset) {
for (int fd = 0; fd < MAX_FDS; ++fd) {
if (s_fd_table[fd].vfs_index == i) {
const int local_fd = s_fd_table[fd].local_fd; // single read -> no locking is required
if (readfds && esp_vfs_safe_fd_isset(local_fd, &item->readfds)) {
ESP_LOGD(TAG, "FD %d in readfds was set from VFS ID %d", fd, i);
FD_SET(fd, readfds);
++ret;
}
if (writefds && esp_vfs_safe_fd_isset(local_fd, &item->writefds)) {
ESP_LOGD(TAG, "FD %d in writefds was set from VFS ID %d", fd, i);
FD_SET(fd, writefds);
++ret;
}
if (errorfds && esp_vfs_safe_fd_isset(local_fd, &item->errorfds)) {
ESP_LOGD(TAG, "FD %d in errorfds was set from VFS ID %d", fd, i);
FD_SET(fd, errorfds);
++ret;
}
}
}
}
}
return ret;
}
static void esp_vfs_log_fd_set(const char *fds_name, const fd_set *fds)
{
if (fds_name && fds) {
ESP_LOGD(TAG, "FDs in %s =", fds_name);
for (int i = 0; i < MAX_FDS; ++i) {
if (esp_vfs_safe_fd_isset(i, fds)) {
ESP_LOGD(TAG, "%d", i);
}
}
}
}
int esp_vfs_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *timeout)
{
// NOTE: Please see the "Synchronous input/output multiplexing" section of the ESP-IDF Programming Guide
// (API Reference -> Storage -> Virtual Filesystem) for a general overview of the implementation of VFS select().
int ret = 0;
struct _reent* r = __getreent();
ESP_LOGD(TAG, "esp_vfs_select starts with nfds = %d", nfds);
if (timeout) {
ESP_LOGD(TAG, "timeout is %lds + %ldus", (long)timeout->tv_sec, timeout->tv_usec);
}
esp_vfs_log_fd_set("readfds", readfds);
esp_vfs_log_fd_set("writefds", writefds);
esp_vfs_log_fd_set("errorfds", errorfds);
if (nfds > MAX_FDS || nfds < 0) {
ESP_LOGD(TAG, "incorrect nfds");
__errno_r(r) = EINVAL;
return -1;
}
// Capture s_vfs_count to a local variable in case a new driver is registered or removed during this actual select()
// call. s_vfs_count cannot be protected with a mutex during a select() call (which can be one without a timeout)
// because that could block the registration of new driver.
const size_t vfs_count = s_vfs_count;
fds_triple_t *vfs_fds_triple;
if ((vfs_fds_triple = calloc(vfs_count, sizeof(fds_triple_t))) == NULL) {
__errno_r(r) = ENOMEM;
ESP_LOGD(TAG, "calloc is unsuccessful");
return -1;
}
esp_vfs_select_sem_t sel_sem = {
.is_sem_local = false,
.sem = NULL,
};
int (*socket_select)(int, fd_set *, fd_set *, fd_set *, struct timeval *) = NULL;
for (int fd = 0; fd < nfds; ++fd) {
_lock_acquire(&s_fd_table_lock);
const bool is_socket_fd = s_fd_table[fd].permanent;
const int vfs_index = s_fd_table[fd].vfs_index;
const int local_fd = s_fd_table[fd].local_fd;
if (esp_vfs_safe_fd_isset(fd, errorfds)) {
s_fd_table[fd].has_pending_select = true;
}
_lock_release(&s_fd_table_lock);
if (vfs_index < 0) {
continue;
}
if (is_socket_fd) {
if (!socket_select) {
// no socket_select found yet so take a look
if (esp_vfs_safe_fd_isset(fd, readfds) ||
esp_vfs_safe_fd_isset(fd, writefds) ||
esp_vfs_safe_fd_isset(fd, errorfds)) {
const vfs_entry_t *vfs = s_vfs[vfs_index];
socket_select = vfs->vfs.socket_select;
sel_sem.sem = vfs->vfs.get_socket_select_semaphore();
}
}
continue;
}
fds_triple_t *item = &vfs_fds_triple[vfs_index]; // FD sets for VFS which belongs to fd
if (esp_vfs_safe_fd_isset(fd, readfds)) {
item->isset = true;
FD_SET(local_fd, &item->readfds);
FD_CLR(fd, readfds);
ESP_LOGD(TAG, "removing %d from readfds and adding as local FD %d to fd_set of VFS ID %d", fd, local_fd, vfs_index);
}
if (esp_vfs_safe_fd_isset(fd, writefds)) {
item->isset = true;
FD_SET(local_fd, &item->writefds);
FD_CLR(fd, writefds);
ESP_LOGD(TAG, "removing %d from writefds and adding as local FD %d to fd_set of VFS ID %d", fd, local_fd, vfs_index);
}
if (esp_vfs_safe_fd_isset(fd, errorfds)) {
item->isset = true;
FD_SET(local_fd, &item->errorfds);
FD_CLR(fd, errorfds);
ESP_LOGD(TAG, "removing %d from errorfds and adding as local FD %d to fd_set of VFS ID %d", fd, local_fd, vfs_index);
}
}
// all non-socket VFSs have their FD sets in vfs_fds_triple
// the global readfds, writefds and errorfds contain only socket FDs (if
// there any)
if (!socket_select) {
// There is no socket VFS registered or select() wasn't called for
// any socket. Therefore, we will use our own signalization.
sel_sem.is_sem_local = true;
if ((sel_sem.sem = xSemaphoreCreateBinary()) == NULL) {
free(vfs_fds_triple);
__errno_r(r) = ENOMEM;
ESP_LOGD(TAG, "cannot create select semaphore");
return -1;
}
}
void **driver_args = calloc(vfs_count, sizeof(void *));
if (driver_args == NULL) {
free(vfs_fds_triple);
__errno_r(r) = ENOMEM;
ESP_LOGD(TAG, "calloc is unsuccessful for driver args");
return -1;
}
for (size_t i = 0; i < vfs_count; ++i) {
const vfs_entry_t *vfs = get_vfs_for_index(i);
fds_triple_t *item = &vfs_fds_triple[i];
if (vfs && vfs->vfs.start_select && item->isset) {
// call start_select for all non-socket VFSs with has at least one FD set in readfds, writefds, or errorfds
// note: it can point to socket VFS but item->isset will be false for that
ESP_LOGD(TAG, "calling start_select for VFS ID %d with the following local FDs", i);
esp_vfs_log_fd_set("readfds", &item->readfds);
esp_vfs_log_fd_set("writefds", &item->writefds);
esp_vfs_log_fd_set("errorfds", &item->errorfds);
esp_err_t err = vfs->vfs.start_select(nfds, &item->readfds, &item->writefds, &item->errorfds, sel_sem,
driver_args + i);
if (err != ESP_OK) {
call_end_selects(i, vfs_fds_triple, driver_args);
(void) set_global_fd_sets(vfs_fds_triple, vfs_count, readfds, writefds, errorfds);
if (sel_sem.is_sem_local && sel_sem.sem) {
vSemaphoreDelete(sel_sem.sem);
sel_sem.sem = NULL;
}
free(vfs_fds_triple);
free(driver_args);
__errno_r(r) = EINTR;
ESP_LOGD(TAG, "start_select failed: %s", esp_err_to_name(err));
return -1;
}
}
}
if (socket_select) {
ESP_LOGD(TAG, "calling socket_select with the following FDs");
esp_vfs_log_fd_set("readfds", readfds);
esp_vfs_log_fd_set("writefds", writefds);
esp_vfs_log_fd_set("errorfds", errorfds);
ret = socket_select(nfds, readfds, writefds, errorfds, timeout);
ESP_LOGD(TAG, "socket_select returned %d and the FDs are the following", ret);
esp_vfs_log_fd_set("readfds", readfds);
esp_vfs_log_fd_set("writefds", writefds);
esp_vfs_log_fd_set("errorfds", errorfds);
} else {
if (readfds) {
FD_ZERO(readfds);
}
if (writefds) {
FD_ZERO(writefds);
}
if (errorfds) {
FD_ZERO(errorfds);
}
TickType_t ticks_to_wait = portMAX_DELAY;
if (timeout) {
uint32_t timeout_ms = (timeout->tv_sec * 1000) + (timeout->tv_usec / 1000);
/* Round up the number of ticks.
* Not only we need to round up the number of ticks, but we also need to add 1.
* Indeed, `select` function shall wait for AT LEAST timeout, but on FreeRTOS,
* if we specify a timeout of 1 tick to `xSemaphoreTake`, it will take AT MOST
* 1 tick before triggering a timeout. Thus, we need to pass 2 ticks as a timeout
* to `xSemaphoreTake`. */
ticks_to_wait = ((timeout_ms + portTICK_PERIOD_MS - 1) / portTICK_PERIOD_MS) + 1;
ESP_LOGD(TAG, "timeout is %dms", timeout_ms);
}
ESP_LOGD(TAG, "waiting without calling socket_select");
xSemaphoreTake(sel_sem.sem, ticks_to_wait);
}
call_end_selects(vfs_count, vfs_fds_triple, driver_args); // for VFSs for start_select was called before
if (ret >= 0) {
ret += set_global_fd_sets(vfs_fds_triple, vfs_count, readfds, writefds, errorfds);
}
if (sel_sem.sem) { // Cleanup the select semaphore
if (sel_sem.is_sem_local) {
vSemaphoreDelete(sel_sem.sem);
} else if (socket_select) {
SemaphoreHandle_t *s = sel_sem.sem;
/* Select might have been triggered from both lwip and vfs fds at the same time, and
* we have to make sure that the lwip semaphore is cleared when we exit select().
* It is safe, as the semaphore belongs to the calling thread. */
xSemaphoreTake(*s, 0);
}
sel_sem.sem = NULL;
}
_lock_acquire(&s_fd_table_lock);
for (int fd = 0; fd < nfds; ++fd) {
if (s_fd_table[fd].has_pending_close) {
s_fd_table[fd] = FD_TABLE_ENTRY_UNUSED;
}
}
_lock_release(&s_fd_table_lock);
free(vfs_fds_triple);
free(driver_args);
ESP_LOGD(TAG, "esp_vfs_select returns %d", ret);
esp_vfs_log_fd_set("readfds", readfds);
esp_vfs_log_fd_set("writefds", writefds);
esp_vfs_log_fd_set("errorfds", errorfds);
return ret;
}
void esp_vfs_select_triggered(esp_vfs_select_sem_t sem)
{
if (sem.is_sem_local) {
xSemaphoreGive(sem.sem);
} else {
// Another way would be to go through s_fd_table and find the VFS
// which has a permanent FD. But in order to avoid to lock
// s_fd_table_lock we go through the VFS table.
for (int i = 0; i < s_vfs_count; ++i) {
// Note: s_vfs_count could have changed since the start of vfs_select() call. However, that change doesn't
// matter here stop_socket_select() will be called for only valid VFS drivers.
const vfs_entry_t *vfs = s_vfs[i];
if (vfs != NULL && vfs->vfs.stop_socket_select != NULL) {
vfs->vfs.stop_socket_select(sem.sem);
break;
}
}
}
}
void esp_vfs_select_triggered_isr(esp_vfs_select_sem_t sem, BaseType_t *woken)
{
if (sem.is_sem_local) {
xSemaphoreGiveFromISR(sem.sem, woken);
} else {
// Another way would be to go through s_fd_table and find the VFS
// which has a permanent FD. But in order to avoid to lock
// s_fd_table_lock we go through the VFS table.
for (int i = 0; i < s_vfs_count; ++i) {
// Note: s_vfs_count could have changed since the start of vfs_select() call. However, that change doesn't
// matter here stop_socket_select() will be called for only valid VFS drivers.
const vfs_entry_t *vfs = s_vfs[i];
if (vfs != NULL && vfs->vfs.stop_socket_select_isr != NULL) {
vfs->vfs.stop_socket_select_isr(sem.sem, woken);
break;
}
}
}
}
#endif // CONFIG_VFS_SUPPORT_SELECT
#ifdef CONFIG_VFS_SUPPORT_TERMIOS
int tcgetattr(int fd, struct termios *p)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, tcgetattr, local_fd, p);
return ret;
}
int tcsetattr(int fd, int optional_actions, const struct termios *p)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, tcsetattr, local_fd, optional_actions, p);
return ret;
}
int tcdrain(int fd)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, tcdrain, local_fd);
return ret;
}
int tcflush(int fd, int select)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, tcflush, local_fd, select);
return ret;
}
int tcflow(int fd, int action)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, tcflow, local_fd, action);
return ret;
}
pid_t tcgetsid(int fd)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, tcgetsid, local_fd);
return ret;
}
int tcsendbreak(int fd, int duration)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
const int local_fd = get_local_fd(vfs, fd);
struct _reent* r = __getreent();
if (vfs == NULL || local_fd < 0) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, tcsendbreak, local_fd, duration);
return ret;
}
#endif // CONFIG_VFS_SUPPORT_TERMIOS
/* Create aliases for newlib syscalls
These functions are also available in ROM as stubs which use the syscall table, but linking them
directly here saves an additional function call when a software function is linked to one, and
makes linking with -stdlib easier.
*/
#ifdef CONFIG_VFS_SUPPORT_IO
int _open_r(struct _reent *r, const char * path, int flags, int mode)
__attribute__((alias("esp_vfs_open")));
int _close_r(struct _reent *r, int fd)
__attribute__((alias("esp_vfs_close")));
ssize_t _read_r(struct _reent *r, int fd, void * dst, size_t size)
__attribute__((alias("esp_vfs_read")));
ssize_t _write_r(struct _reent *r, int fd, const void * data, size_t size)
__attribute__((alias("esp_vfs_write")));
ssize_t pread(int fd, void *dst, size_t size, off_t offset)
__attribute__((alias("esp_vfs_pread")));
ssize_t pwrite(int fd, const void *src, size_t size, off_t offset)
__attribute__((alias("esp_vfs_pwrite")));
off_t _lseek_r(struct _reent *r, int fd, off_t size, int mode)
__attribute__((alias("esp_vfs_lseek")));
int _fcntl_r(struct _reent *r, int fd, int cmd, int arg)
__attribute__((alias("esp_vfs_fcntl_r")));
int _fstat_r(struct _reent *r, int fd, struct stat * st)
__attribute__((alias("esp_vfs_fstat")));
int fsync(int fd)
__attribute__((alias("esp_vfs_fsync")));
int ioctl(int fd, int cmd, ...)
__attribute__((alias("esp_vfs_ioctl")));
#endif // CONFIG_VFS_SUPPORT_IO
#ifdef CONFIG_VFS_SUPPORT_SELECT
int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *timeout)
__attribute__((alias("esp_vfs_select")));
#endif // CONFIG_VFS_SUPPORT_SELECT
#ifdef CONFIG_VFS_SUPPORT_DIR
int _stat_r(struct _reent *r, const char * path, struct stat * st)
__attribute__((alias("esp_vfs_stat")));
int _link_r(struct _reent *r, const char* n1, const char* n2)
__attribute__((alias("esp_vfs_link")));
int _unlink_r(struct _reent *r, const char *path)
__attribute__((alias("esp_vfs_unlink")));
int _rename_r(struct _reent *r, const char *src, const char *dst)
__attribute__((alias("esp_vfs_rename")));
int truncate(const char *path, off_t length)
__attribute__((alias("esp_vfs_truncate")));
int ftruncate(int fd, off_t length)
__attribute__((alias("esp_vfs_ftruncate")));
int access(const char *path, int amode)
__attribute__((alias("esp_vfs_access")));
int utime(const char *path, const struct utimbuf *times)
__attribute__((alias("esp_vfs_utime")));
int rmdir(const char* name)
__attribute__((alias("esp_vfs_rmdir")));
int mkdir(const char* name, mode_t mode)
__attribute__((alias("esp_vfs_mkdir")));
DIR* opendir(const char* name)
__attribute__((alias("esp_vfs_opendir")));
int closedir(DIR* pdir)
__attribute__((alias("esp_vfs_closedir")));
int readdir_r(DIR* pdir, struct dirent* entry, struct dirent** out_dirent)
__attribute__((alias("esp_vfs_readdir_r")));
struct dirent* readdir(DIR* pdir)
__attribute__((alias("esp_vfs_readdir")));
long telldir(DIR* pdir)
__attribute__((alias("esp_vfs_telldir")));
void seekdir(DIR* pdir, long loc)
__attribute__((alias("esp_vfs_seekdir")));
void rewinddir(DIR* pdir)
__attribute__((alias("esp_vfs_rewinddir")));
#endif // CONFIG_VFS_SUPPORT_DIR
void vfs_include_syscalls_impl(void)
{
// Linker hook function, exists to make the linker examine this fine
}
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