[PATCH] getcwd: Set errno to EINVAL when size == 0

[Michael Forney <mforney@mforney.org>]

According to POSIX,

    The getcwd() function shall fail if:

    [EINVAL]
    The size argument is 0.
    [ERANGE]
    The size argument is greater than 0, but is smaller than the length
    of the string +1.
---
 src/unistd/getcwd.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/unistd/getcwd.c b/src/unistd/getcwd.c
index 2e540cd..0238fa7 100644
--- a/src/unistd/getcwd.c
+++ b/src/unistd/getcwd.c
@@ -8,6 +8,10 @@ char *getcwd(char *buf, size_t size)
 {
 	char tmp[PATH_MAX];
 	if (!buf) buf = tmp, size = PATH_MAX;
+	else if (size == 0) {
+		errno = EINVAL;
+		return 0;
+	}
 	if (syscall(SYS_getcwd, buf, size) < 0) return 0;
 	return buf == tmp ? strdup(buf) : buf;
 }
-- 
1.8.4