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VFS: Fix bug which occurs when driver is installed during a select() call

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Closes https://github.com/espressif/esp-idf/issues/3554
This commit is contained in:
Roland Dobai
2019-10-14 09:22:55 +02:00
parent 27a4802f92
commit 8b56496efa
3 changed files with 85 additions and 6 deletions
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20
components/vfs/vfs.c
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@@ -877,8 +877,12 @@ int esp_vfs_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds
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(s_vfs_count, sizeof(fds_triple_t))) == NULL) {
if ((vfs_fds_triple = calloc(vfs_count, sizeof(fds_triple_t))) == NULL) {
__errno_r(r) = ENOMEM;
ESP_LOGD(TAG, "calloc is unsuccessful");
return -1;
@@ -952,7 +956,7 @@ int esp_vfs_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds
}
}
void **driver_args = calloc(s_vfs_count, sizeof(void *));
void **driver_args = calloc(vfs_count, sizeof(void *));
if (driver_args == NULL) {
free(vfs_fds_triple);
@@ -961,7 +965,7 @@ int esp_vfs_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds
return -1;
}
for (int i = 0; i < s_vfs_count; ++i) {
for (int i = 0; i < vfs_count; ++i) {
const vfs_entry_t *vfs = get_vfs_for_index(i);
fds_triple_t *item = &vfs_fds_triple[i];
@@ -977,7 +981,7 @@ int esp_vfs_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds
if (err != ESP_OK) {
call_end_selects(i, vfs_fds_triple, driver_args);
(void) set_global_fd_sets(vfs_fds_triple, s_vfs_count, readfds, writefds, errorfds);
(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;
@@ -1022,9 +1026,9 @@ int esp_vfs_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds
xSemaphoreTake(sel_sem.sem, ticks_to_wait);
}
call_end_selects(s_vfs_count, vfs_fds_triple, driver_args); // for VFSs for start_select was called before
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, s_vfs_count, readfds, writefds, errorfds);
ret += 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);
@@ -1049,6 +1053,8 @@ void esp_vfs_select_triggered(esp_vfs_select_sem_t sem)
// 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);
@@ -1067,6 +1073,8 @@ void esp_vfs_select_triggered_isr(esp_vfs_select_sem_t sem, BaseType_t *woken)
// 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);