From 2148c669d2fe8352ed3b4c1d42e55d90ecc4b68d Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 5 Jan 2024 16:31:55 +0100 Subject: [PATCH] fileio: add new flag WRITE_STRING_FILE_MODE_0444 With this write_string_file() will create the file with 0444 access mode (i.e. read-only). --- src/basic/fileio.c | 17 +++++++++++++++-- src/basic/fileio.h | 3 ++- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/src/basic/fileio.c b/src/basic/fileio.c index 752a65646f..f19326b711 100644 --- a/src/basic/fileio.c +++ b/src/basic/fileio.c @@ -200,6 +200,19 @@ int write_string_stream_ts( return 0; } +static mode_t write_string_file_flags_to_mode(WriteStringFileFlags flags) { + + /* We support three different modes, that are the ones that really make sense for text files like this: + * + * → 0600 (i.e. root-only) + * → 0444 (i.e. read-only) + * → 0644 (i.e. writable for root, readable for everyone else) + */ + + return FLAGS_SET(flags, WRITE_STRING_FILE_MODE_0600) ? 0600 : + FLAGS_SET(flags, WRITE_STRING_FILE_MODE_0444) ? 0444 : 0644; +} + static int write_string_file_atomic_at( int dir_fd, const char *fn, @@ -225,7 +238,7 @@ static int write_string_file_atomic_at( if (r < 0) goto fail; - r = fchmod_umask(fileno(f), FLAGS_SET(flags, WRITE_STRING_FILE_MODE_0600) ? 0600 : 0644); + r = fchmod_umask(fileno(f), write_string_file_flags_to_mode(flags)); if (r < 0) goto fail; @@ -288,7 +301,7 @@ int write_string_file_ts_at( (FLAGS_SET(flags, WRITE_STRING_FILE_CREATE) ? O_CREAT : 0) | (FLAGS_SET(flags, WRITE_STRING_FILE_TRUNCATE) ? O_TRUNC : 0) | (FLAGS_SET(flags, WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL) ? O_RDWR : O_WRONLY), - (FLAGS_SET(flags, WRITE_STRING_FILE_MODE_0600) ? 0600 : 0666)); + write_string_file_flags_to_mode(flags)); if (fd < 0) { r = -errno; goto fail; diff --git a/src/basic/fileio.h b/src/basic/fileio.h index e0e0a45b2b..5b247bc101 100644 --- a/src/basic/fileio.h +++ b/src/basic/fileio.h @@ -26,7 +26,8 @@ typedef enum { WRITE_STRING_FILE_NOFOLLOW = 1 << 8, WRITE_STRING_FILE_MKDIR_0755 = 1 << 9, WRITE_STRING_FILE_MODE_0600 = 1 << 10, - WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL = 1 << 11, + WRITE_STRING_FILE_MODE_0444 = 1 << 11, + WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL = 1 << 12, /* And before you wonder, why write_string_file_atomic_label_ts() is a separate function instead of just one more flag here: it's about linking: we don't want to pull -lselinux into all users of write_string_file()