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authorThomas Weißschuh <thomas.weissschuh@linutronix.de>2025-07-04 15:43:13 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-08-15 16:38:31 +0200
commit88f1daf5a24012cee79b885e8015811fa4c61d94 (patch)
treeb163c1b776d554cfac4da811dea40c85a6624aa5
parent4b303b150bdcc49bd972922081329b2c00e26241 (diff)
selftests/nolibc: correctly report errors from printf() and friends
[ Upstream commit 4a40129087a4c32135bb1177a57bbbe6ee646f1a ] When an error is encountered by printf() it needs to be reported. errno() is already set by the callback. sprintf() is different, but that keeps working and is already tested. Also add a new test. Fixes: 7e4346f4a3a6 ("tools/nolibc/stdio: add a minimal [vf]printf() implementation") Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Acked-by: Willy Tarreau <w@1wt.eu> Link: https://lore.kernel.org/r/20250704-nolibc-printf-error-v1-2-74b7a092433b@linutronix.de Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--tools/include/nolibc/stdio.h4
-rw-r--r--tools/testing/selftests/nolibc/nolibc-test.c23
2 files changed, 25 insertions, 2 deletions
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index c470d334ef3f..7630234408c5 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -358,11 +358,11 @@ int __nolibc_printf(__nolibc_printf_cb cb, intptr_t state, size_t n, const char
n -= w;
while (width-- > w) {
if (cb(state, " ", 1) != 0)
- break;
+ return -1;
written += 1;
}
if (cb(state, outstr, w) != 0)
- break;
+ return -1;
}
written += len;
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index dbe13000fb1a..b5c04c137249 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1646,6 +1646,28 @@ int test_strerror(void)
return 0;
}
+static int test_printf_error(void)
+{
+ int fd, ret, saved_errno;
+
+ fd = open("/dev/full", O_RDWR);
+ if (fd == -1)
+ return 1;
+
+ errno = 0;
+ ret = dprintf(fd, "foo");
+ saved_errno = errno;
+ close(fd);
+
+ if (ret != -1)
+ return 2;
+
+ if (saved_errno != ENOSPC)
+ return 3;
+
+ return 0;
+}
+
static int run_printf(int min, int max)
{
int test;
@@ -1675,6 +1697,7 @@ static int run_printf(int min, int max)
CASE_TEST(width_trunc); EXPECT_VFPRINTF(25, " ", "%25d", 1); break;
CASE_TEST(scanf); EXPECT_ZR(1, test_scanf()); break;
CASE_TEST(strerror); EXPECT_ZR(1, test_strerror()); break;
+ CASE_TEST(printf_error); EXPECT_ZR(1, test_printf_error()); break;
case __LINE__:
return ret; /* must be last */
/* note: do not set any defaults so as to permit holes above */