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Remove all fclose with stdin, stdout and stderr

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since it is wrong to close the builtin stream and specially note
https://pubs.opengroup.org/onlinepubs/9699919799/functions/fclose.html:

Since after the call to fclose() any use of stream results in
undefined behavior, fclose() should not be used on stdin, stdout,
or stderr except immediately before process termination (see XBD
Process Termination), so as to avoid triggering undefined behavior
in other standard interfaces that rely on these streams. If there
are any atexit() handlers registered by the application, such a
call to fclose() should not occur until the last handler is
finishing. Once fclose() has been used to close stdin, stdout, or
stderr, there is no standard way to reopen any of these streams.

and it is also unnecessary because the stream always get flushed.

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
This commit is contained in:
Xiang Xiao 2020-10-13 15:53:19 +08:00 committed by Masayuki Ishikawa
parent 36b1be0609
commit e76ab9c868
5 changed files with 7 additions and 56 deletions
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3
examples/nxterm/nxterm_main.c
View File

@ -391,9 +391,6 @@ int main(int argc, FAR char *argv[])
fflush(stdout);
fflush(stderr);
fclose(stdout);
fclose(stderr);
dup2(fd, 1);
dup2(fd, 2);

12
graphics/nxwm/src/cnxterm.cxx
View File

@ -503,24 +503,12 @@ int CNxTerm::nxterm(int argc, char *argv[])
std::fflush(stdout);
std::fflush(stderr);
#ifdef CONFIG_NXTERM_NXKBDIN
std::fclose(stdin);
#endif
std::fclose(stdout);
std::fclose(stderr);
#ifdef CONFIG_NXTERM_NXKBDIN
std::dup2(fd, 0);
#endif
std::dup2(fd, 1);
std::dup2(fd, 2);
#ifdef CONFIG_NXTERM_NXKBDIN
std::fdopen(0, "r");
#endif
std::fdopen(1, "w");
std::fdopen(2, "w");
// And we can close our original driver file descriptor
if (fd > 2)

12
graphics/twm4nx/apps/cnxterm.cxx
View File

@ -417,24 +417,12 @@ int CNxTerm::nxterm(int argc, char *argv[])
std::fflush(stdout);
std::fflush(stderr);
#ifdef CONFIG_NXTERM_NXKBDIN
std::fclose(stdin);
#endif
std::fclose(stdout);
std::fclose(stderr);
#ifdef CONFIG_NXTERM_NXKBDIN
std::dup2(fd, 0);
#endif
std::dup2(fd, 1);
std::dup2(fd, 2);
#ifdef CONFIG_NXTERM_NXKBDIN
std::fdopen(0, "r");
#endif
std::fdopen(1, "w");
std::fdopen(2, "w");
// And we can close our original driver file descriptor
if (fd > 2)

15
nshlib/nsh_altconsole.c
View File

@ -78,9 +78,9 @@ static int nsh_clone_console(FAR struct console_stdio_s *pstate)
return -ENODEV;
}
/* Close stderr: we only close stderr if we opened the alternative one */
/* Flush stderr: we only flush stderr if we opened the alternative one */
fclose(stderr);
fflush(stderr);
/* Associate the new opened file descriptor to stderr */
@ -101,9 +101,9 @@ static int nsh_clone_console(FAR struct console_stdio_s *pstate)
return -ENODEV;
}
/* Close stdout: we only close stdout if we opened the alternative one */
/* Flush stdout: we only flush stdout if we opened the alternative one */
fclose(stdout);
fflush(stdout);
/* Associate the new opened file descriptor to stdout */
@ -122,7 +122,6 @@ static int nsh_clone_console(FAR struct console_stdio_s *pstate)
pstate->cn_errstream = fdopen(pstate->cn_errfd, "a");
if (!pstate->cn_errstream)
{
close(pstate->cn_errfd);
free(pstate);
return -EIO;
}
@ -133,7 +132,6 @@ static int nsh_clone_console(FAR struct console_stdio_s *pstate)
pstate->cn_outstream = fdopen(pstate->cn_outfd, "a");
if (!pstate->cn_outstream)
{
close(pstate->cn_outfd);
free(pstate);
return -EIO;
}
@ -202,10 +200,6 @@ static int nsh_wait_inputdev(FAR struct console_stdio_s *pstate,
}
while (fd < 0);
/* Close stdin: we only closed stdin if we opened the alternative one */
fclose(stdin);
/* Okay.. we have successfully opened the input device. Did
* we just re-open fd 0?
*/
@ -225,7 +219,6 @@ static int nsh_wait_inputdev(FAR struct console_stdio_s *pstate,
pstate->cn_constream = fdopen(pstate->cn_confd, "r+");
if (!pstate->cn_constream)
{
close(pstate->cn_confd);
free(pstate);
return -EIO;
}

21
nshlib/nsh_usbconsole.c
View File

@ -77,31 +77,16 @@
static void nsh_configstdio(int fd)
{
/* Make sure the stdin, stdout, and stderr are closed */
/* Make sure the stdout, and stderr are flushed */
fclose(stdin);
fclose(stdout);
fclose(stderr);
fflush(stdout);
fflush(stderr);
/* Dup the fd to create standard fd 0-2 */
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
/* fdopen to get the stdin, stdout and stderr streams. The following logic
* depends on the fact that the library layer will allocate FILEs in order.
* And since we closed stdin, stdout, and stderr above, that is what we
* should get.
*
* fd = 0 is stdin (read-only)
* fd = 1 is stdout (write-only, append)
* fd = 2 is stderr (write-only, append)
*/
fdopen(0, "r");
fdopen(1, "a");
fdopen(2, "a");
}
/****************************************************************************