Remove fgets() compatbility function and related tests.

This patch removes the `tor_fgets()` wrapper around `fgets(3)` since it
is no longer needed. The function was created due to inconsistency
between the returned values of `fgets(3)` on different versions of Unix
when using `fgets(3)` on non-blocking file descriptors, but with the
recent changes in bug #21654 we switch from unbuffered to direct I/O on
non-blocking file descriptors in our utility module.

We continue to use `fgets(3)` directly in the geoip and dirserv module
since this usage is considered safe.

This patch also removes the test-case that was created to detect
differences in the implementation of `fgets(3)` as well as the changes
file since these changes was not included in any releases yet.

See: https://bugs.torproject.org/21654

2 files changed, 0 insertions, 41 deletions

diff --git a/src/common/compat.c b/src/common/compat.c
index da4283fbaa..0dbede6bed 100644
--- a/src/common/compat.c
+++ b/src/common/compat.c
@@ -3476,45 +3476,6 @@ tor_getpass(const char *prompt, char *output, size_t buflen)
 #endif
 }
 
-/** Read at most one less than the number of characters specified by
- * <b>size</b> from the given <b>stream</b> and store it in <b>str</b>.
- *
- * Reading stops when a newline character is found or at EOF or error. If any
- * characters are read and there's no error, a trailing NUL byte is appended to
- * the end of <b>str</b>.
- *
- * Upon successful completion, this function returns a pointer to the string
- * <b>str</b>. If EOF occurs before any characters are read the function will
- * return NULL and the content of <b>str</b> is unchanged. Upon error, the
- * function returns NULL and the caller must check for error using foef(3) and
- * ferror(3).
- */
-char *
-tor_fgets(char *str, int size, FILE *stream)
-{
-  char *ret;
-
-  /* Reset errno before our call to fgets(3) to avoid a situation where the
-   * caller is calling us again because we just returned NULL and errno ==
-   * EAGAIN, but when they call us again we will always return NULL because the
-   * error flag on the file handler remains set and errno is set to EAGAIN.
-   */
-  errno = 0;
-
-  ret = fgets(str, size, stream);
-
-  /* FreeBSD, OpenBSD, Linux (glibc), and Linux (musl) seem to disagree about
-   * what to do in the given situation. We check if the stream has been flagged
-   * with an error-bit and return NULL in that situation if errno is also set
-   * to EAGAIN.
-   */
-  if (ferror(stream) && errno == EAGAIN) {
-    return NULL;
-  }
-
-  return ret;
-}
-
 /** Return the amount of free disk space we have permission to use, in
  * bytes. Return -1 if the amount of free space can't be determined. */
 int64_t
diff --git a/src/common/compat.h b/src/common/compat.h
index 1f51ece61f..ee1c9454de 100644
--- a/src/common/compat.h
+++ b/src/common/compat.h
@@ -740,8 +740,6 @@ STATIC int tor_ersatz_socketpair(int family, int type, int protocol,
 
 ssize_t tor_getpass(const char *prompt, char *output, size_t buflen);
 
-char *tor_fgets(char *str, int size, FILE *stream);
-
 /* This needs some of the declarations above so we include it here. */
 #include "compat_threads.h"