X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=unix%2Fuxagentc.c;h=326ee66b832439e35cb40a471339bc989074669c;hb=1bdeff715c9b8c79ec5dc021b5aca403f575f1ae;hp=826e4394b6d6f7e5b9bb23f547c8129ca0245ffc;hpb=6eec320f0b3606f17f06a290acdbb8f84afdff00;p=PuTTY.git

diff --git a/unix/uxagentc.c b/unix/uxagentc.c
index 826e4394..326ee66b 100644
--- a/unix/uxagentc.c
+++ b/unix/uxagentc.c
@@ -8,6 +8,7 @@
 #include <unistd.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <fcntl.h>
 
 #include "putty.h"
 #include "misc.h"
@@ -16,7 +17,8 @@
 
 int agent_exists(void)
 {
-    if (getenv("SSH_AUTH_SOCK") != NULL)
+    const char *p = getenv("SSH_AUTH_SOCK");
+    if (p && *p)
 	return TRUE;
     return FALSE;
 }
@@ -51,35 +53,32 @@ static int agent_connfind(void *av, void *bv)
     return 0;
 }
 
-static int agent_select_result(int fd, int event)
+/*
+ * Attempt to read from an agent socket fd. Returns 0 if the expected
+ * response is as yet incomplete; returns 1 if it's either complete
+ * (conn->retbuf non-NULL and filled with something useful) or has
+ * failed totally (conn->retbuf is NULL).
+ */
+static int agent_try_read(struct agent_connection *conn)
 {
     int ret;
-    struct agent_connection *conn;
-
-    assert(event == 1);		       /* not selecting for anything but R */
-
-    conn = find234(agent_connections, &fd, agent_connfind);
-    if (!conn) {
-	uxsel_del(fd);
-	return 1;
-    }
 
-    ret = read(fd, conn->retbuf+conn->retlen, conn->retsize-conn->retlen);
+    ret = read(conn->fd, conn->retbuf+conn->retlen,
+               conn->retsize-conn->retlen);
     if (ret <= 0) {
 	if (conn->retbuf != conn->sizebuf) sfree(conn->retbuf);
 	conn->retbuf = NULL;
 	conn->retlen = 0;
-	goto done;
+        return 1;
     }
     conn->retlen += ret;
     if (conn->retsize == 4 && conn->retlen == 4) {
-	conn->retsize = GET_32BIT(conn->retbuf);
+	conn->retsize = toint(GET_32BIT(conn->retbuf) + 4);
 	if (conn->retsize <= 0) {
 	    conn->retbuf = NULL;
 	    conn->retlen = 0;
-	    goto done;
+            return -1;                 /* way too large */
 	}
-	conn->retsize += 4;
 	assert(conn->retbuf == conn->sizebuf);
 	conn->retbuf = snewn(conn->retsize, char);
 	memcpy(conn->retbuf, conn->sizebuf, 4);
@@ -88,7 +87,24 @@ static int agent_select_result(int fd, int event)
     if (conn->retlen < conn->retsize)
 	return 0;		       /* more data to come */
 
-    done:
+    return 1;
+}
+
+static int agent_select_result(int fd, int event)
+{
+    struct agent_connection *conn;
+
+    assert(event == 1);		       /* not selecting for anything but R */
+
+    conn = find234(agent_connections, &fd, agent_connfind);
+    if (!conn) {
+	uxsel_del(fd);
+	return 1;
+    }
+
+    if (!agent_try_read(conn))
+	return 0;		       /* more data to come */
+
     /*
      * We have now completed the agent query. Do the callback, and
      * clean up. (Of course we don't free retbuf, since ownership
@@ -121,6 +137,8 @@ int agent_query(void *in, int inlen, void **out, int *outlen,
 	exit(1);
     }
 
+    cloexec(sock);
+
     addr.sun_family = AF_UNIX;
     strncpy(addr.sun_path, name, sizeof(addr.sun_path));
     if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
@@ -137,9 +155,6 @@ int agent_query(void *in, int inlen, void **out, int *outlen,
 	done += ret;
     }
 
-    if (!agent_connections)
-	agent_connections = newtree234(agent_conncmp);
-
     conn = snew(struct agent_connection);
     conn->fd = sock;
     conn->retbuf = conn->sizebuf;
@@ -147,6 +162,34 @@ int agent_query(void *in, int inlen, void **out, int *outlen,
     conn->retlen = 0;
     conn->callback = callback;
     conn->callback_ctx = callback_ctx;
+
+    if (!callback) {
+        /*
+         * Bodge to permit making deliberately synchronous agent
+         * requests. Used by Unix Pageant in command-line client mode,
+         * which is legit because it really is true that no other part
+         * of the program is trying to get anything useful done
+         * simultaneously. But this special case shouldn't be used in
+         * any more general program.
+         */
+        no_nonblock(conn->fd);
+        while (!agent_try_read(conn))
+            /* empty loop body */;
+
+        *out = conn->retbuf;
+        *outlen = conn->retlen;
+        sfree(conn);
+        return 1;
+    }
+
+    /*
+     * Otherwise do it properly: add conn to the tree of agent
+     * connections currently in flight, return 0 to indicate that the
+     * response hasn't been received yet, and call the callback when
+     * select_result comes back to us.
+     */
+    if (!agent_connections)
+	agent_connections = newtree234(agent_conncmp);
     add234(agent_connections, conn);
 
     uxsel_set(sock, 1, agent_select_result);