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authorThomas Weißschuh <thomas.weissschuh@linutronix.de>2025-07-04 15:43:13 +0200
committerThomas Weißschuh <linux@weissschuh.net>2025-07-06 11:02:40 +0200
commit4a40129087a4c32135bb1177a57bbbe6ee646f1a (patch)
tree5d33f393134161c99bca94f40b5205ee61b96fff
parent2b1ed5f7f8ab82597abfff56a39f056f8592df43 (diff)
selftests/nolibc: correctly report errors from printf() and friends
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>
-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 ef80861105f5..a297ee0d6d07 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1662,6 +1662,28 @@ 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;
@@ -1691,6 +1713,7 @@ 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 */