Implement truncate(2).

This adds a simple implementation of truncate in terms of open and
ftruncate.

diff --git a/expected/wasm32-wasi/defined-symbols.txt b/expected/wasm32-wasi/defined-symbols.txt
index 73f5d77b55f3d0630de7db9fe0ff6f25309e471a..ef518849e49d9e601dd4d15dcd925f288e318a28 100644 (file)
--- a/expected/wasm32-wasi/defined-symbols.txt
+++ b/expected/wasm32-wasi/defined-symbols.txt
@@ -992,6 +992,7 @@ towlower_l
 towupper
 towupper_l
 trunc
+truncate
 truncf
 truncl
 tsearch

diff --git a/libc-bottom-half/sources/truncate.c b/libc-bottom-half/sources/truncate.c
new file mode 100644 (file)
index 0000000..b56123d
--- /dev/null
+++ b/libc-bottom-half/sources/truncate.c
@@ -0,0 +1,23 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+
+int truncate(const char *path, off_t length)
+{
+    int fd = open(path, O_WRONLY | O_CLOEXEC | O_NOCTTY);
+    if (fd < 0)
+        return -1;
+
+    int result = ftruncate(fd, length);
+    if (result < 0) {
+        int save_errno = errno;
+        (void)close(fd);
+        errno = save_errno;
+        return -1;
+    }
+
+    if (close(fd) < 0)
+        return -1;
+
+    return 0;
+}