[patch v2] fgets: more tests
DJ Delorie
dj@redhat.com
Tue Aug 20 02:04:35 GMT 2024
changes since v1:
* wrapped includes in DIAG_*
* a few printf->FAIL
* reformat FAIL messages
* macroize PASSes
Add more tests for unusual situations fgets() might see:
* zero size file
* zero sized buffer
* NULL buffer
* NUL data
* writable stream
* closed stream
diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index a91754f52d..30c9637e72 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -209,6 +209,7 @@ tests := \
tst-fdopen \
tst-ferror \
tst-fgets \
+ tst-fgets2 \
tst-fileno \
tst-fmemopen \
tst-fmemopen2 \
diff --git a/stdio-common/tst-fgets2.c b/stdio-common/tst-fgets2.c
new file mode 100644
index 0000000000..e0127317bb
--- /dev/null
+++ b/stdio-common/tst-fgets2.c
@@ -0,0 +1,360 @@
+/* Test for additional fgets error handling.
+ Copyright (C) 2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#define _GNU_SOURCE 1
+
+#include <libc-diag.h>
+DIAG_PUSH_NEEDS_COMMENT;
+/* We're intentionally passing an invalid size and/or NULL later. */
+DIAG_IGNORE_NEEDS_COMMENT (7, "-Wnonnull");
+#include <stdio.h>
+#include <error.h>
+#include <errno.h>
+#include <limits.h>
+#include <mcheck.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+DIAG_POP_NEEDS_COMMENT;
+
+#include <support/support.h>
+#include <support/check.h>
+
+#define PASS() printf("ok\n")
+
+/*------------------------------------------------------------*/
+/* Implementation of our FILE stream backend. */
+
+static int bytes_read;
+static int bytes_written;
+static int cookie_valid = 0;
+struct Cookie {
+ const char *buffer;
+ int bufptr;
+ int bufsz;
+};
+
+#define VALIDATE_COOKIE() if (! cookie_valid) { \
+ FAIL ("call to %s after file closed", __FUNCTION__); \
+ return -1; \
+ }
+
+static ssize_t
+io_read (void *vcookie, char *buf, size_t size)
+{
+ struct Cookie *cookie = (struct Cookie *) vcookie;
+
+ VALIDATE_COOKIE ();
+
+ if (size > cookie->bufsz - cookie->bufptr)
+ size = cookie->bufsz - cookie->bufptr;
+
+ memcpy (buf, cookie->buffer + cookie->bufptr, size);
+ cookie->bufptr += size;
+ bytes_read += size;
+ return size;
+}
+
+static ssize_t
+io_write (void *vcookie, const char *buf, size_t size)
+{
+ VALIDATE_COOKIE ();
+
+ bytes_written += size;
+ return -1;
+}
+
+static int
+io_seek (void *vcookie, off64_t *position, int whence)
+{
+ VALIDATE_COOKIE ();
+ return -1;
+}
+
+static int
+io_clean (void *vcookie)
+{
+ struct Cookie *cookie = (struct Cookie *) vcookie;
+
+ VALIDATE_COOKIE ();
+
+ cookie->buffer = NULL;
+ cookie->bufsz = 0;
+ cookie->bufptr = 0;
+
+ cookie_valid = 0;
+ free (cookie);
+ return 0;
+}
+
+cookie_io_functions_t io_funcs = {
+ .read = io_read,
+ .write = io_write,
+ .seek = io_seek,
+ .close = io_clean
+};
+
+FILE *
+io_open (const char *buffer, int buflen, const char *mode, void **vcookie)
+{
+ FILE *f;
+ struct Cookie *cookie;
+
+ cookie = (struct Cookie *) xcalloc (1, sizeof (struct Cookie));
+ *vcookie = cookie;
+ cookie_valid = 1;
+
+ cookie->buffer = buffer;
+ cookie->bufsz = buflen;
+ bytes_read = 0;
+ bytes_written = 0;
+
+ f = fopencookie (cookie, mode, io_funcs);
+ if (f == NULL)
+ {
+ perror ("fopencookie");
+ exit (1);
+ }
+
+ return f;
+}
+
+/*------------------------------------------------------------*/
+/* Convenience functions. */
+
+static char *
+hex (const char *b, int s)
+{
+ static int bi = 0;
+ static char buf[3][100];
+ static char digit[] = "0123456789ABCDEF";
+ char *bp;
+ if (s > 30)
+ exit (1);
+ bi = (bi+1)%3;
+ bp = buf[bi];
+ while (s > 0)
+ {
+ if (isgraph (*b))
+ *bp ++ = *b;
+ else if (*b == '\n')
+ {
+ *bp ++ = '\\';
+ *bp ++ = 'n';
+ }
+ else if (*b == '\0')
+ {
+ *bp ++ = '\\';
+ *bp ++ = '0';
+ }
+ else
+ {
+ *bp ++ = 'x';
+ *bp ++ = digit[(*b >> 4) & 0x0f];
+ *bp ++ = digit[*b & 0x0f];
+ }
+ b ++;
+ s --;
+ }
+ *bp = 0;
+ return buf[bi];
+}
+
+#define my_open(s,l,m) io_open (s, l, m, (void *) &cookie)
+
+/*------------------------------------------------------------*/
+/* The test cases. */
+
+static int
+do_test (void)
+{
+ FILE *f;
+ struct Cookie *cookie;
+ char buf [100];
+ char *str;
+
+ printf ("testing base operation...");
+ f = my_open ("hello\n", 6, "r");
+ memset (buf, 0x11, sizeof (buf));
+ str = fgets (buf, 100, f);
+ if (str == NULL)
+ {
+ FAIL ("returned NULL");
+ }
+ else if (memcmp (str, "hello\n\0", 7) != 0)
+ {
+ FAIL ("returned %s instead of %s", hex (str, 7), hex ("hello\n\0", 7));
+ }
+ else if (bytes_read != 6)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 6);
+ }
+ else
+ PASS ();
+ fclose (f);
+
+ printf ("testing zero size file...");
+ f = my_open ("hello\n", 0, "r");
+ memset (buf, 0x11, sizeof (buf));
+ str = fgets (buf, 100, f);
+ if (str != NULL)
+ {
+ FAIL ("returned %s instead of NULL", hex (str, strlen (str)));
+ }
+ else if (bytes_read != 0)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 0);
+ }
+ else
+ PASS ();
+ fclose (f);
+
+ printf ("testing zero size buffer...");
+ f = my_open ("hello\n", 6, "r");
+ memset (buf, 0x11, sizeof (buf));
+ str = fgets (buf, 0, f);
+ if (str != NULL)
+ {
+ FAIL ("returned %s instead of NULL", hex (str, strlen (str)));
+ }
+ else if (bytes_read != 0)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 0);
+ }
+ else
+ PASS ();
+ fclose (f);
+
+ printf ("testing NULL buffer...");
+ f = my_open ("hello\n", 0, "r");
+ memset (buf, 0x11, sizeof (buf));
+
+ DIAG_PUSH_NEEDS_COMMENT;
+ /* We're intentionally passing an invalid size here. */
+ DIAG_IGNORE_NEEDS_COMMENT (7, "-Wnonnull");
+ str = fgets (NULL, 100, f);
+ DIAG_POP_NEEDS_COMMENT;
+
+ if (str != NULL)
+ {
+ FAIL ("returned %s instead of NULL", hex (str, strlen (str)));
+ }
+ else if (bytes_read != 0)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 0);
+ }
+ else
+ PASS ();
+ fclose (f);
+
+ printf ("testing embedded NUL...");
+ f = my_open ("hel\0lo\n", 7, "r");
+ memset (buf, 0x11, sizeof (buf));
+ str = fgets (buf, 100, f);
+ if (str == NULL)
+ {
+ FAIL ("returned NULL");
+ }
+ else if (memcmp (str, "hel\0lo\n\0", 8) != 0)
+ {
+ FAIL ("returned %s instead of %s", hex (str, 8), hex ("hel\0lo\n\0", 8));
+ }
+ else if (bytes_read != 7)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 7);
+ }
+ else
+ PASS ();
+ fclose (f);
+
+ printf ("testing writable stream...");
+ f = my_open ("hel\0lo\n", 7, "w");
+ memset (buf, 0x11, sizeof (buf));
+ str = fgets (buf, 100, f);
+ if (str != NULL)
+ {
+ FAIL ("returned %s instead of NULL", hex (str, strlen (str)));
+ }
+ else if (bytes_read != 0)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 0);
+ }
+ else
+ PASS ();
+ fclose (f);
+
+ printf ("testing closed fd stream...");
+ int fd = open ("/dev/null", O_RDONLY);
+ f = fdopen (fd, "r");
+ close (fd);
+ memset (buf, 0x11, sizeof (buf));
+ str = fgets (buf, 100, f);
+ if (str != NULL)
+ {
+ FAIL ("returned %s instead of NULL", hex (str, strlen (str)));
+ }
+ else if (bytes_read != 0)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 0);
+ }
+ else
+ PASS ();
+ fclose (f);
+
+#ifdef IO_DEBUG
+ /* These tests only pass if glibc is built with -DIO_DEBUG. */
+
+ printf ("testing NULL descriptor...");
+ memset (buf, 0x11, sizeof (buf));
+ str = fgets (buf, 100, NULL);
+ if (str != NULL)
+ {
+ FAIL ("returned %s instead of NULL", hex (str, strlen (str)));
+ }
+ else if (bytes_read != 0)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 0);
+ }
+ else
+ PASS ();
+
+ printf ("testing closed descriptor...");
+ f = my_open ("hello\n", 7, "r");
+ fclose (f);
+ memset (buf, 0x11, sizeof (buf));
+ str = fgets (buf, 100, f);
+ if (str != NULL)
+ {
+ FAIL ("returned %s instead of NULL", hex (str, strlen (str)));
+ }
+ else if (bytes_read != 0)
+ {
+ FAIL ("%d bytes read instead of %d", bytes_read, 0);
+ }
+ else
+ PASS ();
+#endif
+
+ return 0;
+}
+
+#include <support/test-driver.c>
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