| From 4cf08811e112100a2b10c60047f3c537ad21d674 Mon Sep 17 00:00:00 2001 |
| From: David Seifert <soap@gentoo.org> |
| Date: Sat, 28 Jan 2023 14:22:42 +0100 |
| Subject: [PATCH] Use `freopen()` on {stdin,stdout,stderr} |
| |
| * ISO C does not guarantee that the standard streams are modifiable |
| lvalues. Glibc even calls out this behaviour as non-portable: |
| https://www.gnu.org/software/libc/manual/html_node/Standard-Streams.html |
| --- |
| lib/log/log.c | 4 ++++ |
| tools/lvmcmdline.c | 6 +++--- |
| 2 files changed, 7 insertions(+), 3 deletions(-) |
| |
| diff --git a/lib/log/log.c b/lib/log/log.c |
| index 118a3ba42..a94016d81 100644 |
| --- a/lib/log/log.c |
| +++ b/lib/log/log.c |
| @@ -208,7 +208,11 @@ int reopen_standard_stream(FILE **stream, const char *mode) |
| |
| _check_and_replace_standard_log_streams(old_stream, new_stream); |
| |
| +#ifdef __GLIBC__ |
| *stream = new_stream; |
| +#else |
| + freopen(NULL, mode, *stream); |
| +#endif |
| return 1; |
| } |
| |
| diff --git a/tools/lvmcmdline.c b/tools/lvmcmdline.c |
| index a5bb6a5c5..0ebfa375c 100644 |
| --- a/tools/lvmcmdline.c |
| +++ b/tools/lvmcmdline.c |
| @@ -3422,7 +3422,7 @@ static int _check_standard_fds(void) |
| int err = is_valid_fd(STDERR_FILENO); |
| |
| if (!is_valid_fd(STDIN_FILENO) && |
| - !(stdin = fopen(_PATH_DEVNULL, "r"))) { |
| + !freopen(_PATH_DEVNULL, "r", stdin)) { |
| if (err) |
| perror("stdin stream open"); |
| else |
| @@ -3432,7 +3432,7 @@ static int _check_standard_fds(void) |
| } |
| |
| if (!is_valid_fd(STDOUT_FILENO) && |
| - !(stdout = fopen(_PATH_DEVNULL, "w"))) { |
| + !freopen(_PATH_DEVNULL, "w", stdout)) { |
| if (err) |
| perror("stdout stream open"); |
| /* else no stdout */ |
| @@ -3440,7 +3440,7 @@ static int _check_standard_fds(void) |
| } |
| |
| if (!is_valid_fd(STDERR_FILENO) && |
| - !(stderr = fopen(_PATH_DEVNULL, "w"))) { |
| + !freopen(_PATH_DEVNULL, "w", stderr)) { |
| printf("stderr stream open: %s\n", |
| strerror(errno)); |
| return 0; |
| -- |
| 2.39.2 |
| |
