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lib/os: fdtable: add locking to posix api

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Added locking to posix read(), write(), close()
for additional protection.

In read() missing lock would create uneven calls to locking
mechanism in sockets.c after k_condvar_wait().
That results in socket lock not ever being unlocked

Signed-off-by: Daniel Nejezchleb <dnejezchleb@hwg.cz>
This commit is contained in:
Daniel Nejezchleb 2022-02-09 18:48:58 +01:00 • committed by Carles Cufí
commit b68bdf20cf
1 changed files with 22 additions and 2 deletions
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24
lib/os/fdtable.c
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@ -224,21 +224,37 @@ int z_alloc_fd(void *obj, const struct fd_op_vtable *vtable)
ssize_t read(int fd, void *buf, size_t sz) ssize_t read(int fd, void *buf, size_t sz)
{ {
ssize_t res;
if (_check_fd(fd) < 0) { if (_check_fd(fd) < 0) {
return -1; return -1;
} }
return fdtable[fd].vtable->read(fdtable[fd].obj, buf, sz); (void)k_mutex_lock(&fdtable[fd].lock, K_FOREVER);
res = fdtable[fd].vtable->read(fdtable[fd].obj, buf, sz);
k_mutex_unlock(&fdtable[fd].lock);
return res;
} }
FUNC_ALIAS(read, _read, ssize_t); FUNC_ALIAS(read, _read, ssize_t);
ssize_t write(int fd, const void *buf, size_t sz) ssize_t write(int fd, const void *buf, size_t sz)
{ {
ssize_t res;
if (_check_fd(fd) < 0) { if (_check_fd(fd) < 0) {
return -1; return -1;
} }
return fdtable[fd].vtable->write(fdtable[fd].obj, buf, sz); (void)k_mutex_lock(&fdtable[fd].lock, K_FOREVER);
res = fdtable[fd].vtable->write(fdtable[fd].obj, buf, sz);
k_mutex_unlock(&fdtable[fd].lock);
return res;
} }
FUNC_ALIAS(write, _write, ssize_t); FUNC_ALIAS(write, _write, ssize_t);
@ -250,8 +266,12 @@ int close(int fd)
return -1; return -1;
} }
(void)k_mutex_lock(&fdtable[fd].lock, K_FOREVER);
res = fdtable[fd].vtable->close(fdtable[fd].obj); res = fdtable[fd].vtable->close(fdtable[fd].obj);
k_mutex_unlock(&fdtable[fd].lock);
z_free_fd(fd); z_free_fd(fd);
return res; return res;