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Merge pull request #15417 from poettering/fileno-can-fail

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fileio: fileno() can realistically return -1
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2020-04-14 12:54:27 +02:00 committed by GitHub
commit 3cfb7cc507
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5 changed files with 67 additions and 25 deletions
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48
src/basic/fileio.c
View File

@ -119,7 +119,7 @@ int write_string_stream_ts(
struct timespec *ts) {
bool needs_nl;
int r;
int r, fd;
assert(f);
assert(line);
@ -127,6 +127,14 @@ int write_string_stream_ts(
if (ferror(f))
return -EIO;
if (ts) {
/* If we shall set the timestamp we need the fd. But fmemopen() streams generally don't have
* an fd. Let's fail early in that case. */
fd = fileno(f);
if (fd < 0)
return -EBADF;
}
needs_nl = !(flags & WRITE_STRING_FILE_AVOID_NEWLINE) && !endswith(line, "\n");
if (needs_nl && (flags & WRITE_STRING_FILE_DISABLE_BUFFER)) {
@ -154,7 +162,7 @@ int write_string_stream_ts(
if (ts) {
struct timespec twice[2] = {*ts, *ts};
if (futimens(fileno(f), twice) < 0)
if (futimens(fd, twice) < 0)
return -errno;
}
@ -886,7 +894,7 @@ int fflush_and_check(FILE *f) {
}
int fflush_sync_and_check(FILE *f) {
int r;
int r, fd;
assert(f);
@ -894,10 +902,16 @@ int fflush_sync_and_check(FILE *f) {
if (r < 0)
return r;
if (fsync(fileno(f)) < 0)
/* Not all file streams have an fd associated (think: fmemopen()), let's handle this gracefully and
* assume that in that case we need no explicit syncing */
fd = fileno(f);
if (fd < 0)
return 0;
if (fsync(fd) < 0)
return -errno;
r = fsync_directory_of_file(fileno(f));
r = fsync_directory_of_file(fd);
if (r < 0)
return r;
@ -995,7 +1009,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, funlockfile);
int read_line_full(FILE *f, size_t limit, ReadLineFlags flags, char **ret) {
size_t n = 0, allocated = 0, count = 0;
_cleanup_free_ char *buffer = NULL;
int r, tty = -1;
int r;
assert(f);
@ -1070,13 +1084,23 @@ int read_line_full(FILE *f, size_t limit, ReadLineFlags flags, char **ret) {
count++;
if (eol != EOL_NONE) {
/* If we are on a tty, we can't wait for more input. But we expect only
* \n as the single EOL marker, so there is no need to wait. We check
* this condition last to avoid isatty() check if not necessary. */
/* If we are on a tty, we can't shouldn't wait for more input, because that
* generally means waiting for the user, interactively. In the case of a TTY
* we expect only \n as the single EOL marker, so we are in the lucky
* position that there is no need to wait. We check this condition last, to
* avoid isatty() check if not necessary. */
if (tty < 0)
tty = isatty(fileno(f));
if (tty > 0)
if ((flags & (READ_LINE_IS_A_TTY|READ_LINE_NOT_A_TTY)) == 0) {
int fd;
fd = fileno(f);
if (fd < 0) /* Maybe an fmemopen() stream? Handle this gracefully,
* and don't call isatty() on an invalid fd */
flags |= READ_LINE_NOT_A_TTY;
else
flags |= isatty(fd) ? READ_LINE_IS_A_TTY : READ_LINE_NOT_A_TTY;
}
if (FLAGS_SET(flags, READ_LINE_IS_A_TTY))
break;
}

4
src/basic/fileio.h
View File

@ -88,7 +88,9 @@ int read_timestamp_file(const char *fn, usec_t *ret);
int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space);
typedef enum ReadLineFlags {
READ_LINE_ONLY_NUL = 1 << 0,
READ_LINE_ONLY_NUL = 1 << 0,
READ_LINE_IS_A_TTY = 1 << 1,
READ_LINE_NOT_A_TTY = 1 << 2,
} ReadLineFlags;
int read_line_full(FILE *f, size_t limit, ReadLineFlags flags, char **ret);

32
src/basic/terminal-util.c
View File

@ -81,31 +81,34 @@ int chvt(int vt) {
int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
_cleanup_free_ char *line = NULL;
struct termios old_termios;
int r;
int r, fd;
assert(f);
assert(ret);
/* If this is a terminal, then switch canonical mode off, so that we can read a single character */
if (tcgetattr(fileno(f), &old_termios) >= 0) {
/* If this is a terminal, then switch canonical mode off, so that we can read a single
* character. (Note that fmemopen() streams do not have an fd associated with them, let's handle that
* nicely.) */
fd = fileno(f);
if (fd >= 0 && tcgetattr(fd, &old_termios) >= 0) {
struct termios new_termios = old_termios;
new_termios.c_lflag &= ~ICANON;
new_termios.c_cc[VMIN] = 1;
new_termios.c_cc[VTIME] = 0;
if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
if (tcsetattr(fd, TCSADRAIN, &new_termios) >= 0) {
char c;
if (t != USEC_INFINITY) {
if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
(void) tcsetattr(fileno(f), TCSADRAIN, &old_termios);
if (fd_wait_for_event(fd, POLLIN, t) <= 0) {
(void) tcsetattr(fd, TCSADRAIN, &old_termios);
return -ETIMEDOUT;
}
}
r = safe_fgetc(f, &c);
(void) tcsetattr(fileno(f), TCSADRAIN, &old_termios);
(void) tcsetattr(fd, TCSADRAIN, &old_termios);
if (r < 0)
return r;
if (r == 0)
@ -119,8 +122,13 @@ int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
}
}
if (t != USEC_INFINITY) {
if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
if (t != USEC_INFINITY && fd > 0) {
/* Let's wait the specified amount of time for input. When we have no fd we skip this, under
* the assumption that this is an fmemopen() stream or so where waiting doesn't make sense
* anyway, as the data is either already in the stream or cannot possible be placed there
* while we access the stream */
if (fd_wait_for_event(fd, POLLIN, t) <= 0)
return -ETIMEDOUT;
}
@ -778,6 +786,9 @@ const char *default_term_for_tty(const char *tty) {
int fd_columns(int fd) {
struct winsize ws = {};
if (fd < 0)
return -EBADF;
if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
return -errno;
@ -812,6 +823,9 @@ unsigned columns(void) {
int fd_lines(int fd) {
struct winsize ws = {};
if (fd < 0)
return -EBADF;
if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
return -errno;

2
src/libsystemd/sd-hwdb/hwdb-util.c
View File

@ -488,7 +488,7 @@ static int import_file(struct trie *trie, const char *filename, uint16_t file_pr
size_t len;
char *pos;
r = read_line(f, LONG_LINE_MAX, &line);
r = read_line_full(f, LONG_LINE_MAX, READ_LINE_NOT_A_TTY, &line);
if (r < 0)
return r;
if (r == 0)

6
src/shared/conf-parser.c
View File

@ -294,7 +294,7 @@ int config_parse(const char *unit,
_cleanup_fclose_ FILE *ours = NULL;
unsigned line = 0, section_line = 0;
bool section_ignored = false, bom_seen = false;
int r;
int r, fd;
assert(filename);
assert(lookup);
@ -311,7 +311,9 @@ int config_parse(const char *unit,
}
}
fd_warn_permissions(filename, fileno(f));
fd = fileno(f);
if (fd >= 0) /* stream might not have an fd, let's be careful hence */
fd_warn_permissions(filename, fd);
for (;;) {
_cleanup_free_ char *buf = NULL;