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-rw-r--r--src/stdio/fclose.c7
-rw-r--r--src/stdio/feof.c5
-rw-r--r--src/stdio/ferror.c5
-rw-r--r--src/stdio/fileno.c5
-rw-r--r--src/stdio/freopen.c24
-rw-r--r--src/stdio/fwide.c6
6 files changed, 36 insertions, 16 deletions
diff --git a/src/stdio/fclose.c b/src/stdio/fclose.c
index 8fdc3f7d..92bf7ff8 100644
--- a/src/stdio/fclose.c
+++ b/src/stdio/fclose.c
@@ -3,9 +3,12 @@
int fclose(FILE *f)
{
int r;
- int perm = f->flags & F_PERM;
+ int perm;
+
+ /* This lock is not paired with any unlock. */
+ FLOCK(f);
- if (!perm) {
+ if (!(perm = f->flags & F_PERM)) {
OFLLOCK();
if (f->prev) f->prev->next = f->next;
if (f->next) f->next->prev = f->prev;
diff --git a/src/stdio/feof.c b/src/stdio/feof.c
index 5d7f4b02..56da6b91 100644
--- a/src/stdio/feof.c
+++ b/src/stdio/feof.c
@@ -4,7 +4,10 @@
int feof(FILE *f)
{
- return !!(f->flags & F_EOF);
+ FLOCK(f);
+ int ret = !!(f->flags & F_EOF);
+ FUNLOCK(f);
+ return ret;
}
weak_alias(feof, feof_unlocked);
diff --git a/src/stdio/ferror.c b/src/stdio/ferror.c
index 8288a93d..d692eed9 100644
--- a/src/stdio/ferror.c
+++ b/src/stdio/ferror.c
@@ -4,7 +4,10 @@
int ferror(FILE *f)
{
- return !!(f->flags & F_ERR);
+ FLOCK(f);
+ int ret = !!(f->flags & F_ERR);
+ FUNLOCK(f);
+ return ret;
}
weak_alias(ferror, ferror_unlocked);
diff --git a/src/stdio/fileno.c b/src/stdio/fileno.c
index 9ffb26d5..ba7f9391 100644
--- a/src/stdio/fileno.c
+++ b/src/stdio/fileno.c
@@ -2,6 +2,11 @@
int fileno(FILE *f)
{
+ /* f->fd never changes, but the lock must be obtained and released
+ * anyway since this function cannot return while another thread
+ * holds the lock. */
+ FLOCK(f);
+ FUNLOCK(f);
return f->fd;
}
diff --git a/src/stdio/freopen.c b/src/stdio/freopen.c
index c80ce3b4..7ae116d8 100644
--- a/src/stdio/freopen.c
+++ b/src/stdio/freopen.c
@@ -4,8 +4,9 @@
* hack the necessary parts of the new FILE into the old one, then
* close the new FILE. */
-/* Locking is not necessary because, in the event of failure, the stream
- * passed to freopen is invalid as soon as freopen is called. */
+/* Locking IS necessary because another thread may provably hold the
+ * lock, via flockfile or otherwise, when freopen is called, and in that
+ * case, freopen cannot act until the lock is released. */
int __dup3(int, int, int);
@@ -14,6 +15,8 @@ FILE *freopen(const char *restrict filename, const char *restrict mode, FILE *re
int fl = __fmodeflags(mode);
FILE *f2;
+ FLOCK(f);
+
fflush(f);
if (!filename) {
@@ -22,21 +25,22 @@ FILE *freopen(const char *restrict filename, const char *restrict mode, FILE *re
fl &= ~(O_CREAT|O_EXCL|O_CLOEXEC);
if (syscall(SYS_fcntl, f->fd, F_SETFL, fl) < 0)
goto fail;
- return f;
} else {
f2 = fopen(filename, mode);
if (!f2) goto fail;
if (f2->fd == f->fd) f2->fd = -1; /* avoid closing in fclose */
else if (__dup3(f2->fd, f->fd, fl&O_CLOEXEC)<0) goto fail2;
- }
- f->flags = (f->flags & F_PERM) | f2->flags;
- f->read = f2->read;
- f->write = f2->write;
- f->seek = f2->seek;
- f->close = f2->close;
+ f->flags = (f->flags & F_PERM) | f2->flags;
+ f->read = f2->read;
+ f->write = f2->write;
+ f->seek = f2->seek;
+ f->close = f2->close;
- fclose(f2);
+ fclose(f2);
+ }
+
+ FUNLOCK(f);
return f;
fail2:
diff --git a/src/stdio/fwide.c b/src/stdio/fwide.c
index f4da47f6..48480685 100644
--- a/src/stdio/fwide.c
+++ b/src/stdio/fwide.c
@@ -5,6 +5,8 @@
int fwide(FILE *f, int mode)
{
- if (!f->mode) f->mode = NORMALIZE(mode);
- return f->mode;
+ FLOCK(f);
+ if (!f->mode) mode = f->mode = NORMALIZE(mode);
+ FUNLOCK(f);
+ return mode;
}