cleanup src/linux and src/misc trees, etc.

previously, it was pretty much random which one of these trees a given
function appeared in. they have now been organized into:

src/linux: non-POSIX linux syscalls (possibly shard with other nixen)
src/legacy: various obsolete/legacy functions, mostly wrappers
src/misc: still mostly uncategorized; some misc POSIX, some nonstd
src/crypt: crypt hash functions

further cleanup will be done later.

1 files changed, 33 insertions, 0 deletions

diff --git a/src/legacy/getusershell.c b/src/legacy/getusershell.c
new file mode 100644
index 00000000..683158c8
--- /dev/null
+++ b/src/legacy/getusershell.c
@@ -0,0 +1,33 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+static const char defshells[] = "/bin/sh\n/bin/csh\n";
+
+static char *line;
+static size_t linesize;
+static FILE *f;
+
+void endusershell(void)
+{
+	if (f) fclose(f);
+	f = 0;
+}
+
+void setusershell(void)
+{
+	if (!f) f = fopen("/etc/shells", "rb");
+	if (!f) f = fmemopen((void *)defshells, sizeof defshells - 1, "rb");
+}
+
+char *getusershell(void)
+{
+	ssize_t l;
+	if (!f) setusershell();
+	if (!f) return 0;
+	l = getline(&line, &linesize, f);
+	if (l <= 0) return 0;
+	if (line[l-1]=='\n') line[l-1]=0;
+	return line;
+}