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authorThomas Weißschuh <thomas.weissschuh@linutronix.de>2025-04-28 14:40:14 +0200
committerThomas Weißschuh <linux@weissschuh.net>2025-05-21 15:32:14 +0200
commita009a0c6faa9e7ffac13d55ef6cdac1f9a68efbe (patch)
tree082ec060d6e79f6647a9a73cb8c91a8280764923
parent256dc7339d466f4d928be48ced6d590a99d447cc (diff)
tools/nolibc: add fopen()
This is used in various selftests and will be handy when integrating those with nolibc. Only the standard POSIX modes are supported. No extensions nor the (noop) "b" from ISO C are accepted. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Acked-by: Willy Tarreau <w@1wt.eu> Link: https://lore.kernel.org/r/20250428-nolibc-misc-v2-13-3c043eeab06c@linutronix.de Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
-rw-r--r--tools/include/nolibc/stdio.h27
-rw-r--r--tools/testing/selftests/nolibc/nolibc-test.c24
2 files changed, 51 insertions, 0 deletions
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index df5717d59182..c470d334ef3f 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -13,6 +13,7 @@
#include "std.h"
#include "arch.h"
#include "errno.h"
+#include "fcntl.h"
#include "types.h"
#include "sys.h"
#include "stdarg.h"
@@ -55,6 +56,32 @@ FILE *fdopen(int fd, const char *mode __attribute__((unused)))
return (FILE*)(intptr_t)~fd;
}
+static __attribute__((unused))
+FILE *fopen(const char *pathname, const char *mode)
+{
+ int flags, fd;
+
+ switch (*mode) {
+ case 'r':
+ flags = O_RDONLY;
+ break;
+ case 'w':
+ flags = O_WRONLY | O_CREAT | O_TRUNC;
+ break;
+ case 'a':
+ flags = O_WRONLY | O_CREAT | O_APPEND;
+ break;
+ default:
+ SET_ERRNO(EINVAL); return NULL;
+ }
+
+ if (mode[1] == '+')
+ flags = (flags & ~(O_RDONLY | O_WRONLY)) | O_RDWR;
+
+ fd = open(pathname, flags, 0666);
+ return fdopen(fd, mode);
+}
+
/* provides the fd of stream. */
static __attribute__((unused))
int fileno(FILE *stream)
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index d1157319b5d7..0391c7d01380 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -859,6 +859,29 @@ int test_getpagesize(void)
return !c;
}
+int test_file_stream(void)
+{
+ FILE *f;
+ int r;
+
+ f = fopen("/dev/null", "r");
+ if (!f)
+ return -1;
+
+ errno = 0;
+ r = fwrite("foo", 1, 3, f);
+ if (r != 0 || errno != EBADF) {
+ fclose(f);
+ return -1;
+ }
+
+ r = fclose(f);
+ if (r == EOF)
+ return -1;
+
+ return 0;
+}
+
int test_fork(void)
{
int status;
@@ -1311,6 +1334,7 @@ int run_syscall(int min, int max)
CASE_TEST(dup3_0); tmp = dup3(0, 100, 0); EXPECT_SYSNE(1, tmp, -1); close(tmp); break;
CASE_TEST(dup3_m1); tmp = dup3(-1, 100, 0); EXPECT_SYSER(1, tmp, -1, EBADF); if (tmp != -1) close(tmp); break;
CASE_TEST(execve_root); EXPECT_SYSER(1, execve("/", (char*[]){ [0] = "/", [1] = NULL }, NULL), -1, EACCES); break;
+ CASE_TEST(file_stream); EXPECT_SYSZR(1, test_file_stream()); break;
CASE_TEST(fork); EXPECT_SYSZR(1, test_fork()); break;
CASE_TEST(getdents64_root); EXPECT_SYSNE(1, test_getdents64("/"), -1); break;
CASE_TEST(getdents64_null); EXPECT_SYSER(1, test_getdents64("/dev/null"), -1, ENOTDIR); break;