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esp-idf/components/vfs/vfs.c

736 wiersze
21 KiB
C
Czysty Wina Historia

// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <sys/errno.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <sys/unistd.h>
#include <sys/param.h>
#include <dirent.h>
#include "esp_vfs.h"
#include "esp_log.h"
#include "port/arch/sys_arch.h"
#include "lwip/sys.h"
#define VFS_MAX_COUNT 8 /* max number of VFS entries (registered filesystems) */
#define MIN_LWIP_FD (FD_SETSIZE - CONFIG_LWIP_MAX_SOCKETS)
#define LEN_PATH_PREFIX_IGNORED SIZE_MAX /* special length value for VFS which is never recognised by open() */
typedef struct vfs_entry_ {
esp_vfs_t vfs; // contains pointers to VFS functions
char path_prefix[ESP_VFS_PATH_MAX]; // path prefix mapped to this VFS
size_t path_prefix_len; // micro-optimization to avoid doing extra strlen
void* ctx; // optional pointer which can be passed to VFS
int offset; // index of this structure in s_vfs array
} vfs_entry_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 short fd_vfs[FD_SETSIZE] = { [0 ... FD_SETSIZE-1] = -1 };
static esp_err_t esp_vfs_register_common(const char* base_path, size_t len, const esp_vfs_t* vfs, void* ctx, int *vfs_entry_index)
{
if (len != LEN_PATH_PREFIX_IGNORED) {
if ((len != 0 && len < 2) || (len > ESP_VFS_PATH_MAX)) {
return ESP_ERR_INVALID_ARG;
}
if ((len > 0 && 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_entry_index) {
*vfs_entry_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_socket_space(const esp_vfs_t *vfs, void *ctx, int *p_min_fd, int *p_max_fd)
{
int index = -1;
esp_err_t ret = esp_vfs_register_common("", LEN_PATH_PREFIX_IGNORED, vfs, ctx, &index);
if (ret == ESP_OK) {
if (p_min_fd != NULL) {
*p_min_fd = MIN_LWIP_FD;
}
if (p_max_fd != NULL) {
*p_max_fd = FD_SETSIZE;
}
}
for (int i = MIN_LWIP_FD; i < FD_SETSIZE; ++i) {
fd_vfs[i] = index;
}
return ret;
}
esp_err_t esp_vfs_unregister(const char* base_path)
{
for (size_t i = 0; i < s_vfs_count; ++i) {
vfs_entry_t* vfs = s_vfs[i];
if (vfs == NULL) {
continue;
}
if (memcmp(base_path, vfs->path_prefix, vfs->path_prefix_len) == 0) {
free(vfs);
s_vfs[i] = NULL;
// Delete all references from the FD lookup-table
for (int j = 0; j < FD_SETSIZE; ++j) {
if (fd_vfs[j] == i) {
fd_vfs[j] = -1;
}
}
return ESP_OK;
}
}
return ESP_ERR_INVALID_STATE;
}
static inline 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 < FD_SETSIZE) && (fd >= 0);
}
static inline const vfs_entry_t* get_vfs_for_fd(int fd)
{
if (fd_valid(fd)) {
return get_vfs_for_index(fd_vfs[fd]);
} else {
return NULL;
}
}
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;
}
static 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 ret;
CHECK_AND_CALL(ret, r, vfs, open, path_within_vfs, flags, mode);
if (ret >= MIN_LWIP_FD) {
CHECK_AND_CALL(ret, r, vfs, close, ret);
__errno_r(r) = ENFILE;
return -1;
}
if (ret >= 0) {
fd_vfs[ret] = vfs->offset;
}
return ret;
}
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);
if (vfs == NULL) {
__errno_r(r) = EBADF;
return -1;
}
ssize_t ret;
CHECK_AND_CALL(ret, r, vfs, write, 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);
if (vfs == NULL) {
__errno_r(r) = EBADF;
return -1;
}
off_t ret;
CHECK_AND_CALL(ret, r, vfs, lseek, 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);
if (vfs == NULL) {
__errno_r(r) = EBADF;
return -1;
}
ssize_t ret;
CHECK_AND_CALL(ret, r, vfs, read, fd, dst, size);
return ret;
}
int esp_vfs_close(struct _reent *r, int fd)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
if (vfs == NULL) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, close, fd);
if (fd < MIN_LWIP_FD) {
fd_vfs[fd] = -1;
} // else { Leave alone socket FDs because sockets are not created by
// esp_vfs_open and therefore fd_vfs won't be set again.
//}
return ret;
}
int esp_vfs_fstat(struct _reent *r, int fd, struct stat * st)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
if (vfs == NULL) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, fstat, fd, st);
return ret;
}
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_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* 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* 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 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 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 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 rewinddir(DIR* pdir)
{
seekdir(pdir, 0);
}
int 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 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 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 fcntl(int fd, int cmd, ...)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
va_list args;
va_start(args, cmd);
CHECK_AND_CALL(ret, r, vfs, fcntl, fd, cmd, args);
va_end(args);
return ret;
}
int ioctl(int fd, int cmd, ...)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
va_list args;
va_start(args, cmd);
CHECK_AND_CALL(ret, r, vfs, ioctl, fd, cmd, args);
va_end(args);
return ret;
}
int fsync(int fd)
{
const vfs_entry_t* vfs = get_vfs_for_fd(fd);
struct _reent* r = __getreent();
if (vfs == NULL) {
__errno_r(r) = EBADF;
return -1;
}
int ret;
CHECK_AND_CALL(ret, r, vfs, fsync, fd);
return ret;
}
static void call_end_selects(int end_index, const fds_triple_t *vfs_fds_triple)
{
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) {
vfs->vfs.end_select();
}
}
}
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 j = 0; j < sizeof(item->readfds.fds_bits)/sizeof(item->readfds.fds_bits[0]); ++j) {
if (readfds != NULL) {
readfds->fds_bits[j] |= item->readfds.fds_bits[j];
ret += __builtin_popcountl(item->readfds.fds_bits[j]);
}
if (writefds != NULL) {
writefds->fds_bits[j] |= item->writefds.fds_bits[j];
ret += __builtin_popcountl(item->writefds.fds_bits[j]);
}
if (errorfds != NULL) {
errorfds->fds_bits[j] |= item->errorfds.fds_bits[j];
ret += __builtin_popcountl(item->errorfds.fds_bits[j]);
}
}
}
}
return ret;
}
int esp_vfs_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *timeout)
{
const int non_socket_nfds = MIN(nfds, MIN_LWIP_FD);
int ret = 0;
struct _reent* r = __getreent();
if (nfds > FD_SETSIZE || nfds < 0) {
__errno_r(r) = EINVAL;
return -1;
}
fds_triple_t *vfs_fds_triple;
if ((vfs_fds_triple = calloc(s_vfs_count, sizeof(fds_triple_t))) == NULL) {
__errno_r(r) = ENOMEM;
return -1;
}
for (int i = 0; i < non_socket_nfds; ++i) {
if (fd_vfs[i] < 0) {
continue;
}
fds_triple_t *item = &vfs_fds_triple[fd_vfs[i]]; // FD sets for VFS which belongs to FD i
if (readfds && FD_ISSET(i, readfds)) {
item->isset = true;
FD_SET(i, &item->readfds);
FD_CLR(i, readfds);
}
if (writefds && FD_ISSET(i, writefds)) {
item->isset = true;
FD_SET(i, &item->writefds);
FD_CLR(i, writefds);
}
if (errorfds && FD_ISSET(i, errorfds)) {
item->isset = true;
FD_SET(i, &item->errorfds);
FD_CLR(i, errorfds);
}
}
// all non-socket VFSs have their FD sets in vfs_fds_triple
// the global readfds, writefds and errorfds contain only socket FDs
void *callback_handle = sys_thread_sem_get();
if (!callback_handle) {
__errno_r(r) = ENOMEM;
return -1;
}
sys_arch_sem_wait(callback_handle, 1); //ensure the semaphore is taken so we are not signalled out-of-sequence; 0 timeout would block forever
for (int i = 0; i < s_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_err_t err = vfs->vfs.start_select(nfds, &item->readfds, &item->writefds, &item->errorfds, callback_handle);
if (err != ESP_OK) {
call_end_selects(i, vfs_fds_triple);
(void) set_global_fd_sets(vfs_fds_triple, s_vfs_count, readfds, writefds, errorfds);
free(vfs_fds_triple);
__errno_r(r) = ENOMEM;
return -1;
}
}
}
int socket_select_called = 0;
for (int i = MIN_LWIP_FD; i < FD_SETSIZE; ++i) {
const vfs_entry_t* vfs = get_vfs_for_fd(i);
if (vfs != NULL && vfs->vfs.socket_select != NULL) {
// find socket VFS and call socket_select
ret = vfs->vfs.socket_select(nfds, readfds, writefds, errorfds, timeout);
socket_select_called = 1;
break;
}
}
if (!socket_select_called) {
uint32_t timeout_ms = 0;
if (readfds) {
FD_ZERO(readfds);
}
if (writefds) {
FD_ZERO(writefds);
}
if (errorfds) {
FD_ZERO(errorfds);
}
if (timeout) {
timeout_ms = timeout->tv_sec * 1000 + timeout->tv_usec / 1000;
timeout_ms = MAX(timeout_ms, 1); //make sure it is not 0 which would be in infinite wait
}
sys_arch_sem_wait(callback_handle, timeout_ms);
sys_sem_free(callback_handle);
}
call_end_selects(s_vfs_count, vfs_fds_triple); // for VFSs for start_select was called before
if (ret >= 0) {
ret += set_global_fd_sets(vfs_fds_triple, s_vfs_count, readfds, writefds, errorfds);
}
//don't free callback_handle because it is freed in lwip_select (vfs.socket_select)
free(vfs_fds_triple);
return ret;
}
void esp_vfs_select_triggered(void *callback_handle)
{
if (callback_handle) {
sys_sem_signal(callback_handle); //vfs->vfs.socket_select will return
}
}
void esp_vfs_select_triggered_isr(void *callback_handle, BaseType_t *woken)
{
if (callback_handle && sys_sem_signal_isr(callback_handle) && woken) {
*woken = pdTRUE;
}
}
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