m + add ascii.h and exec.h

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 92 insertions, 0 deletions

diff --git a/which.c b/which.c
new file mode 100644
index 0000000..96a3ece
--- /dev/null
+++ b/which.c
@@ -0,0 +1,92 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+
+const char *
+libsimple_which(const char *file, int cwdfd, const char *path, char **free_this_out)
+{
+	const char *p, *q;
+	char *buf = NULL;
+	size_t bufsize, len, filelen;
+	int got_eacces = 0, saved_errno = errno;
+
+	free_this_out = NULL;
+
+	if (!file || !free_this_out) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	if (strchr(file, '/'))
+		return file;
+
+	if (!path) {
+		path = getenv("PATH");
+		if (!path)
+			path = "";
+	}
+	if (!*path) {
+		errno = ENOENT;
+		return NULL;
+	}
+
+	bufsize = 0;
+	for (p = path; p; p = q) {
+		q = strchr(p, ':');
+		if (q)
+			len = (size_t)(q++ - p);
+		else
+			len = strlen(p);
+		if (len > bufsize)
+			bufsize = len;
+	}
+	if (bufsize) {
+		filelen = strlen(file) + 1U;
+		bufsize += 1U + filelen;
+		buf = malloc(bufsize);
+		if (!buf)
+			return NULL;
+	}
+
+	for (p = path; p; p = q) {
+		q = strchr(p, ':');
+		if (q)
+			len = (size_t)(q++ - p);
+		else
+			len = strlen(p);
+		if (len) {
+			memcpy(buf, p, len);
+			buf[len] = '/';
+			memcpy(&buf[len + 1], file, filelen);
+			if (!faccessat(cwdfd, buf, X_OK, AT_EACCESS)) {
+				*free_this_out = buf;
+				errno = saved_errno;
+				return buf;
+			}
+		} else {
+			if (!faccessat(cwdfd, file, X_OK, AT_EACCESS)) {
+				errno = saved_errno;
+				return file;
+			}
+		}
+		if (errno == EACCES)
+			got_eacces = 1;
+	}
+
+	free(buf);
+	errno = got_eacces ? EACCES : ENOENT;
+	return NULL;
+}
+
+
+#else
+#include "test.h"
+
+int
+main(void)
+{
+        return 0;
+}
+
+#endif