ip/cifsd: implement primitive per-share unix id mapping for wstat()

1 files changed, 175 insertions, 0 deletions

diff --git a/sys/src/cmd/ip/cifsd/idmap.c b/sys/src/cmd/ip/cifsd/idmap.c
new file mode 100644
index 000000000..178d99b19
--- /dev/null
+++ b/sys/src/cmd/ip/cifsd/idmap.c
@@ -0,0 +1,175 @@
+#include <u.h>
+#include <libc.h>
+#include "dat.h"
+#include "fns.h"
+
+#include <bio.h>
+
+enum {
+	NHASH = 251,
+};
+
+typedef struct Ident Ident;
+struct Ident
+{
+	Ident	*nextid;
+	Ident	*nextname;
+	int	id;
+	char	name[];
+};
+
+struct Idmap
+{
+	Ident	*tab[NHASH];
+};
+
+static Ident**
+nametab(Idmap *map, char *name)
+{
+	return &map->tab[(uint)namehash(name) % NHASH];
+}
+static Ident**
+idtab(Idmap *map, int id)
+{
+	return &map->tab[(uint)id % NHASH];
+}
+
+static int
+name2id(Idmap *map, char *name)
+{
+	Ident *e;
+
+	for(e = *nametab(map, name); e != nil; e = e->nextid){
+		if(strcmp(e->name, name) == 0)
+			return e->id;
+	}
+	return -1;
+}
+
+static char*
+id2name(Idmap *map, int id)
+{
+	Ident *e;
+
+	for(e = *idtab(map, id); e != nil; e = e->nextname){
+		if(e->id == id)
+			return e->name;
+	}
+	return nil;
+}
+
+static void
+idmap(Idmap *map, char *name, int id)
+{
+	Ident *e, **h;
+	int n;
+
+	n = strlen(name)+1;
+	e = malloc(sizeof(Ident)+n);
+	if(e == nil)
+		return;
+
+	e->id = id;
+	h = idtab(map, e->id);
+	e->nextid = *h;
+	*h = e;
+
+	memmove(e->name, name, n);
+	h = nametab(map, e->name);
+	e->nextname = *h;
+	*h = e;
+}
+
+static Idmap*
+readidmap(char *file, int style)
+{
+	Biobuf *b;
+	Idmap *m;
+	char *l, *name;
+	int id;
+
+	if((b = Bopen(file, OREAD)) == nil)
+		return nil;
+
+	if((m = mallocz(sizeof(*m), 1)) == nil)
+		goto Out;
+
+	while((l = Brdline(b, '\n')) != nil){
+		l[Blinelen(b)-1] = 0;
+		switch(style){
+		case '9':
+			id = 9000000 + strtol(l, &l, 10);
+			if(*l != ':')
+				continue;
+			name = ++l;
+			l = strchr(l, ':');
+			if(l == 0)
+				continue;
+			*l = 0;
+			break;
+		default:
+			name = l;
+			l = strchr(l, ':');
+			if(l == 0)
+				continue;
+			*l++ = 0;
+			/* skip password */
+			l = strchr(l, ':');
+			if(l == 0)
+				continue;
+			id = strtol(l+1, 0, 10);
+			break;
+		}
+		idmap(m, name, id);
+	}
+Out:
+	Bterm(b);
+
+	return m;
+}
+
+void
+unixidmap(Share *share)
+{
+	static Idmap emptymap;
+	char *file;
+
+	if(share->stype != STYPE_DISKTREE)
+		goto Out;
+
+	file = smprint("%s/etc/passwd", share->root);
+	share->users = readidmap(file, 'u');
+	free(file);
+	file = smprint("%s/etc/group", share->root);
+	share->groups = readidmap(file, 'u');
+	free(file);
+	if(share->users != nil && share->groups != nil)
+		return;
+
+	file = smprint("%s/adm/users", share->root);
+	share->users = share->groups = readidmap(file, '9');
+	free(file);
+	if(share->users != nil && share->groups != nil)
+		return;
+
+Out:
+	share->users = share->groups = &emptymap;
+}
+
+char*
+unixname(Share *share, int id, int group)
+{
+	return id2name(group? share->groups: share->users, id);
+}
+
+int
+unixuid(Share *share, char *name)
+{
+	return name2id(share->users, name);
+}
+
+int
+unixgid(Share *share, char *name)
+{
+	return name2id(share->groups, name);
+}