From 3d91e6d993c2f76d1c44b2b3d1db8e2a503e55d6 Mon Sep 17 00:00:00 2001 From: Ivan Grokhotkov Date: Wed, 15 Sep 2021 14:49:57 +0200 Subject: [PATCH] newlib: implement _fstat_r stub for console When CONFIG_VFS_SUPPORT_IO is disabled, _read_r and _write_r implementations in syscalls.c are used to provide console I/O via esp_rom_uart_tx_one_char/esp_rom_uart_rx_one_char. When newlib opens a (FILE*) stream, it calls fstat to check if the underlying file is character-oriented. In this case, it configures the stream to use line buffering. Otherwise (or if fstat fails) the stream is opened as block buffered. Since fstat wasn't provided, stdin/stdout/stderr streams got opened in block buffered mode. For console, we need line buffered output so that the stream buffer is flushed each time a complete line (ending with '\n') is sent to stdout or stderr. Fix by implementing _fstat_r stub, setting st->st_mdoe=S_IFCHR. --- components/newlib/syscalls.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/components/newlib/syscalls.c b/components/newlib/syscalls.c index d6c3098592..f9e5300fd9 100644 --- a/components/newlib/syscalls.c +++ b/components/newlib/syscalls.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -64,6 +65,18 @@ ssize_t _read_r_console(struct _reent *r, int fd, void * data, size_t size) return -1; } +static ssize_t _fstat_r_console(struct _reent *r, int fd, struct stat * st) +{ + if (fd == STDOUT_FILENO || fd == STDERR_FILENO) { + memset(st, 0, sizeof(*st)); + /* This needs to be set so that stdout and stderr are line buffered. */ + st->st_mode = S_IFCHR; + return 0; + } + __errno_r(r) = EBADF; + return -1; +} + /* The following weak definitions of syscalls will be used unless * another definition is provided. That definition may come from @@ -73,6 +86,8 @@ ssize_t _read_r(struct _reent *r, int fd, void * dst, size_t size) __attribute__((weak,alias("_read_r_console"))); ssize_t _write_r(struct _reent *r, int fd, const void * data, size_t size) __attribute__((weak,alias("_write_r_console"))); +int _fstat_r (struct _reent *r, int fd, struct stat *st) + __attribute__((weak,alias("_fstat_r_console"))); /* The aliases below are to "syscall_not_implemented", which @@ -90,8 +105,6 @@ off_t _lseek_r(struct _reent *r, int fd, off_t size, int mode) __attribute__((weak,alias("syscall_not_implemented"))); int _fcntl_r(struct _reent *r, int fd, int cmd, int arg) __attribute__((weak,alias("syscall_not_implemented"))); -int _fstat_r(struct _reent *r, int fd, struct stat * st) - __attribute__((weak,alias("syscall_not_implemented"))); int _stat_r(struct _reent *r, const char * path, struct stat * st) __attribute__((weak,alias("syscall_not_implemented"))); int _link_r(struct _reent *r, const char* n1, const char* n2)