stew

commit 0745c973b5032194c33ef481a302eb1bcff8c11d
parent 90ec56c54528056b5caa8b4ee98f11751063d94e
Author: Renev Pavel <an2qzavok@gmail.com>
Date:   Mon,  6 Feb 2023 20:19:17 +0000

srv/wdb: srv - some kind of keyval store

Diffstat:
M
src/wdb/mkfile
 | 
5
++---
A
src/wdb/srv.c
 | 
129
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 131 insertions(+), 3 deletions(-)
diff --git a/src/wdb/mkfile b/src/wdb/mkfile
@@ -1,5 +1,5 @@
 </$objtype/mkfile
-TARG=search
+TARG=search srv
 HFILES=wdb.h util.h
 OFILES=util.$O
-</sys/src/cmd/mkmany
-\ No newline at end of file
+</sys/src/cmd/mkmany
diff --git a/src/wdb/srv.c b/src/wdb/srv.c
@@ -0,0 +1,129 @@
+#include <u.h>
+#include <libc.h>
+
+enum {
+	BufSize = 8192,
+	KeySize = 256,
+};
+
+typedef struct Key Key;
+typedef struct Val Val;
+
+struct Val {
+	long n;
+	char *p;
+};
+
+struct Key {
+	char key[KeySize];
+	Val val;
+	Key *next;
+};
+
+int fd, pd[2];
+Key *keyp;
+
+void srv(void);
+int eval(char *buf, int n);
+
+void
+main(int, char **)
+{
+	pipe(pd);
+	fd = create("/srv/wdb", OWRITE, 0666);
+	fprint(fd, "%d", pd[0]);
+	close(fd);
+	close(pd[0]);
+	close(0);
+	close(1);
+	switch(rfork(RFFDG|RFPROC|RFNAMEG|RFNOTEG|RFREND)) { // TODO: double check flags
+	case -1:
+		fprint(2, "%r\n");
+		exits("fork");
+		break;
+	case 0:
+		srv();
+		break;
+	}
+}
+
+void
+srv(void)
+{
+	int n;
+	char buf[BufSize];
+	for (;;) {
+		memset(buf, 0, BufSize);
+		n = read(pd[1], buf, BufSize);
+		n = eval(buf, n);
+		if (write(pd[1], buf, n) < n) break;
+	}
+	fprint(2, "%r\n");
+}
+
+Key *
+findkey(Key *root, char *key)
+{
+	Key *kp;
+	for (kp = root; kp != nil; kp = kp->next) {
+		if (strncmp(key, kp->key, KeySize) == 0) return kp;
+	}
+	return nil;
+}
+
+int
+setkey(Key **root, char *key, char *p, int n)
+{
+	Key *k = findkey(*root, key);
+	if (k == nil) {
+		k = mallocz(sizeof(Key), 1);
+		strncpy(k->key, key, KeySize);
+		k->next = *root;
+		*root = k;
+	} else if (k->val.p != nil) {
+		free(k->val.p);
+	}
+	if (k == nil) return -1;
+	k->val.n = n;
+	k->val.p = mallocz(n, 1);
+	if (k->val.p == nil) return -1;
+	memcpy(k->val.p, p, n);
+	return 0;
+}
+
+Val *
+getkey(Key *root, char *key)
+{
+	Key *k = findkey(root, key);
+	if (k == nil) return nil;
+	return &(k->val);
+}
+
+int
+eval(char *buf, int n)
+{
+	char *args[3], *act, *key, *data;
+	for (; n > 0; buf++, n--) if (strchr(" \t\n", buf[0]) == nil) break;
+	if (n <= 0) return 0;
+	if (buf[0] == '\n') return 0;
+	if (getfields(buf, args, 3, 1, " \t\n") < 2) return sprint(buf, "error malformed message");
+	act = args[0], key = args[1], data = args[2];
+	if (strlen(act) >= 8) return sprint(buf, "error bad command");
+	if (strlen(key) >= KeySize) return sprint(buf, "error bad key");
+	if (strncmp(act, "store", 8) == 0) {
+		if (setkey(&keyp, key, data, data - buf + n) != 0) {
+			return sprint(buf, "error store failed");
+		} else {
+			return sprint(buf, "ok %s", key);
+		}
+	}
+	if (strncmp(act, "fetch", 8) == 0) {
+		Val *v = getkey(keyp, key);
+		if (v == nil) {
+			return sprint(buf, "nil %s", key);
+		} else {
+			return sprint(buf, "ok %s %s", key, v->p);
+		}
+	}
+	return sprint(buf, "error unknown command");
+}