tests: add inject_randr15 (#2573)

This tool is similar to xtrace in usage in that it intercepts traffic to
the X server. The motivating feature for writing the tool is its ability
to inject prepared reply messages instead of the server’s reply. In
this particular case, we’ll inject a RRGetMonitors reply to test i3’s
RandR 1.5 code paths.

The added testcase is a noop for now, but with the code that’s lingering
in the randr15 branch, i3 does actually detect monitors as per the
injected reply:

    2016-11-20 21:10:05 - randr.c:__randr_query_outputs:618 -
      RandR 1.5 available, querying monitors
    2016-11-20 21:10:05 - randr.c:__randr_query_outputs:628 -
      1 RandR monitors found (timestamp 0)
    2016-11-20 21:10:05 - randr.c:__randr_query_outputs:646 -
      name DP3, x 0, y 0, width 3840 px, height 2160 px, width 520 mm,
      height 290 mm, primary 1, automatic 1

This is preparation work for issue #1799

Makefile.am

@@ -45,7 +45,10 @@ dist_xsessions_DATA = \
 
 noinst_LIBRARIES = libi3.a
 
-check_PROGRAMS = test.commands_parser test.config_parser
+check_PROGRAMS = \
+	test.commands_parser \
+	test.config_parser \
+	test.inject_randr15
 
 check_SCRIPTS = \
 	testcases/complete-run.pl
@@ -401,6 +404,19 @@ i3_config_wizard_i3_config_wizard_SOURCES = \
 	i3-config-wizard/main.c \
 	i3-config-wizard/xcb.h
 
+test_inject_randr15_CPPFLAGS = \
+	$(AM_CPPFLAGS)
+
+test_inject_randr15_CFLAGS = \
+	$(AM_CFLAGS) \
+	$(i3_CFLAGS)
+
+test_inject_randr15_SOURCES = \
+	testcases/inject_randr1.5.c
+
+test_inject_randr15_LDADD = \
+	$(i3_LDADD)
+
 test_commands_parser_CPPFLAGS = \
 	$(AM_CPPFLAGS) \
 	-DTEST_PARSER

testcases/inject_randr1.5.c

@@ -0,0 +1,441 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ * © 2009 Michael Stapelberg and contributors (see also: LICENSE)
+ *
+ * inject_randr1.5.c: An X11 proxy which interprets RandR 1.5 GetMonitors
+ * requests and overwrites their reply with a custom reply.
+ *
+ * This tool can be refactored as necessary in order to perform the same
+ * purpose for other request types. The RandR 1.5 specific portions of the code
+ * have been marked as such to make such a refactoring easier.
+ *
+ */
+#include "all.h"
+
+#include <ev.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <libgen.h>
+
+static void uds_connection_cb(EV_P_ ev_io *w, int revents);
+static void read_client_setup_request_cb(EV_P_ ev_io *w, int revents);
+static void read_server_setup_reply_cb(EV_P_ ev_io *w, int revents);
+static void read_client_x11_packet_cb(EV_P_ ev_io *w, int revents);
+static void read_server_x11_packet_cb(EV_P_ ev_io *w, int revents);
+
+static char *sun_path = NULL;
+
+void cleanup_socket(void) {
+    if (sun_path != NULL) {
+        unlink(sun_path);
+        free(sun_path);
+        sun_path = NULL;
+    }
+}
+
+/* BEGIN RandR 1.5 specific */
+static void *injected_reply = NULL;
+static off_t injected_reply_len = 0;
+/* END RandR 1.5 specific */
+
+#define XCB_PAD(i) (-(i)&3)
+
+struct connstate {
+    /* clientw is a libev watcher for the connection which we accept()ed. */
+    ev_io *clientw;
+
+    /* serverw is a libev watcher for the connection to X11 which we initiated
+	 * on behalf of the client. */
+    ev_io *serverw;
+
+    /* sequence is the client-side sequence number counter. In X11’s wire
+     * encoding, sequence counters are not included in requests, only in
+     * replies. */
+    int sequence;
+
+    /* BEGIN RandR 1.5 specific */
+    /* sequence number of the most recent GetExtension request for RANDR */
+    int getext_randr;
+    /* sequence number of the most recent RRGetMonitors request */
+    int getmonitors;
+
+    int randr_major_opcode;
+    /* END RandR 1.5 specific */
+};
+
+/*
+ * Returns 0 on EOF
+ * Returns -1 on error (with errno from read() untouched)
+ *
+ */
+static size_t readall_into(void *buffer, const size_t len, int fd) {
+    size_t read_bytes = 0;
+    while (read_bytes < len) {
+        ssize_t n = read(fd, buffer + read_bytes, len - read_bytes);
+        if (n <= 0) {
+            return n;
+        }
+        read_bytes += (size_t)n;
+    }
+    return read_bytes;
+}
+
+/*
+ * Exits the program with an error if the read failed.
+ *
+ */
+static void must_read(int n) {
+    if (n == -1) {
+        err(EXIT_FAILURE, "read()");
+    }
+    if (n == 0) {
+        errx(EXIT_FAILURE, "EOF");
+    }
+}
+
+/*
+ * Exits the program with an error if the write failed.
+ *
+ */
+static void must_write(int n) {
+    if (n == -1) {
+        err(EXIT_FAILURE, "write()");
+    }
+}
+
+static void uds_connection_cb(EV_P_ ev_io *w, int revents) {
+    struct sockaddr_un addr;
+    socklen_t addrlen = sizeof(addr);
+    const int clientfd = accept(w->fd, (struct sockaddr *)&addr, &addrlen);
+    if (clientfd == -1) {
+        if (errno == EINTR) {
+            return;
+        }
+        err(EXIT_FAILURE, "accept()");
+    }
+
+    struct connstate *connstate = scalloc(1, sizeof(struct connstate));
+
+    ev_io *clientw = scalloc(1, sizeof(ev_io));
+    connstate->clientw = clientw;
+    clientw->data = connstate;
+    ev_io_init(clientw, read_client_setup_request_cb, clientfd, EV_READ);
+    ev_io_start(EV_A_ clientw);
+}
+
+// https://www.x.org/releases/current/doc/xproto/x11protocol.html#Encoding::Connection_Setup
+static void read_client_setup_request_cb(EV_P_ ev_io *w, int revents) {
+    ev_io_stop(EV_A_ w);
+    struct connstate *connstate = (struct connstate *)w->data;
+
+    /* Read X11 setup request in its entirety. */
+    xcb_setup_request_t setup_request;
+    must_read(readall_into(&setup_request, sizeof(setup_request), w->fd));
+
+    /* Establish a connection to X11. */
+    int fd = socket(AF_LOCAL, SOCK_STREAM, 0);
+    if (fd == -1) {
+        err(EXIT_FAILURE, "socket()");
+    }
+
+    char *host;
+    int displayp;
+    if (xcb_parse_display(getenv("DISPLAY"), &host, &displayp, NULL) == 0) {
+        errx(EXIT_FAILURE, "Could not parse DISPLAY=%s", getenv("DISPLAY"));
+    }
+    free(host);
+
+    struct sockaddr_un addr;
+    memset(&addr, 0, sizeof(addr));
+    addr.sun_family = AF_LOCAL;
+    snprintf(addr.sun_path, sizeof(addr.sun_path), "/tmp/.X11-unix/X%d", displayp);
+    if (connect(fd, (const struct sockaddr *)&addr, sizeof(struct sockaddr_un)) == -1) {
+        err(EXIT_FAILURE, "connect(%s)", addr.sun_path);
+    }
+
+    /* Relay setup request. */
+    must_write(writeall(fd, &setup_request, sizeof(setup_request)));
+
+    if (setup_request.authorization_protocol_name_len > 0 ||
+        setup_request.authorization_protocol_data_len > 0) {
+        const size_t authlen = setup_request.authorization_protocol_name_len +
+                               XCB_PAD(setup_request.authorization_protocol_name_len) +
+                               setup_request.authorization_protocol_data_len +
+                               XCB_PAD(setup_request.authorization_protocol_data_len);
+        void *buf = smalloc(authlen);
+        must_read(readall_into(buf, authlen, w->fd));
+        must_write(writeall(fd, buf, authlen));
+        free(buf);
+    }
+
+    /* Wait for a response from the X11 server. */
+    ev_io *serverw = scalloc(1, sizeof(ev_io));
+    connstate->serverw = serverw;
+    serverw->data = connstate;
+    ev_io_init(serverw, read_server_setup_reply_cb, fd, EV_READ);
+    ev_io_start(EV_A_ serverw);
+}
+
+static void read_server_setup_reply_cb(EV_P_ ev_io *w, int revents) {
+    struct connstate *connstate = (struct connstate *)w->data;
+    xcb_setup_failed_t setup_failed;
+    must_read(readall_into(&setup_failed, sizeof(setup_failed), w->fd));
+
+    switch (setup_failed.status) {
+        case 0:
+            errx(EXIT_FAILURE, "error authenticating at the X11 server");
+
+        case 2:
+            errx(EXIT_FAILURE, "two-factor auth not implemented");
+
+        case 1:
+            must_write(writeall(connstate->clientw->fd, &setup_failed, sizeof(xcb_setup_failed_t)));
+            const size_t len = (setup_failed.length * 4);
+            void *buf = smalloc(len);
+            must_read(readall_into(buf, len, w->fd));
+            must_write(writeall(connstate->clientw->fd, buf, len));
+            free(buf);
+
+            ev_set_cb(connstate->clientw, read_client_x11_packet_cb);
+            ev_set_cb(connstate->serverw, read_server_x11_packet_cb);
+            ev_io_start(EV_A_ connstate->clientw);
+            break;
+
+        default:
+            errx(EXIT_FAILURE, "X11 protocol error: expected setup_failed.status in [0..2], got %d", setup_failed.status);
+    }
+}
+
+// https://www.x.org/releases/current/doc/xproto/x11protocol.html#request_format
+typedef struct {
+    uint8_t opcode;
+    uint8_t pad0;
+    uint16_t length;
+} generic_x11_request_t;
+
+// https://www.x.org/releases/current/doc/xproto/x11protocol.html#reply_format
+typedef struct {
+    uint8_t code; /* if 1, this is a reply. if 0, this is an error. else, an event */
+    uint8_t pad0;
+    uint16_t sequence;
+    uint32_t length;
+} generic_x11_reply_t;
+
+static void read_client_x11_packet_cb(EV_P_ ev_io *w, int revents) {
+    struct connstate *connstate = (struct connstate *)w->data;
+
+    void *request = smalloc(sizeof(generic_x11_request_t));
+    must_read(readall_into(request, sizeof(generic_x11_request_t), connstate->clientw->fd));
+    const size_t len = (((generic_x11_request_t *)request)->length * 4);
+    if (len > sizeof(generic_x11_request_t)) {
+        request = srealloc(request, len);
+        must_read(readall_into(request + sizeof(generic_x11_request_t),
+                               len - sizeof(generic_x11_request_t),
+                               connstate->clientw->fd));
+    }
+
+    // XXX: sequence counter wrapping is not implemented, but should not be
+    // necessary given that this tool is scoped for test cases.
+    connstate->sequence++;
+
+    /* BEGIN RandR 1.5 specific */
+    const uint8_t opcode = ((generic_x11_request_t *)request)->opcode;
+    if (opcode == XCB_QUERY_EXTENSION) {
+        xcb_query_extension_request_t *req = request;
+        const char *name = request + sizeof(xcb_query_extension_request_t);
+        if (req->name_len == strlen("RANDR") &&
+            strncmp(name, "RANDR", strlen("RANDR")) == 0) {
+            connstate->getext_randr = connstate->sequence;
+        }
+    } else if (opcode == connstate->randr_major_opcode) {
+        const uint8_t randr_opcode = ((generic_x11_request_t *)request)->pad0;
+        if (randr_opcode == XCB_RANDR_GET_MONITORS) {
+            connstate->getmonitors = connstate->sequence;
+        }
+    }
+    /* END RandR 1.5 specific */
+
+    must_write(writeall(connstate->serverw->fd, request, len));
+    free(request);
+}
+
+static void read_server_x11_packet_cb(EV_P_ ev_io *w, int revents) {
+    struct connstate *connstate = (struct connstate *)w->data;
+    // all packets from the server are at least 32 bytes in length
+    size_t len = 32;
+    void *packet = smalloc(len);
+    must_read(readall_into(packet, len, connstate->serverw->fd));
+    switch (((generic_x11_reply_t *)packet)->code) {
+        case 0:  // error
+            break;
+
+        case 1:  // reply
+            len += ((generic_x11_reply_t *)packet)->length * 4;
+            if (len > 32) {
+                packet = srealloc(packet, len);
+                must_read(readall_into(packet + 32, len - 32, connstate->serverw->fd));
+            }
+
+            /* BEGIN RandR 1.5 specific */
+            const uint16_t sequence = ((generic_x11_reply_t *)packet)->sequence;
+
+            if (sequence == connstate->getext_randr) {
+                xcb_query_extension_reply_t *reply = packet;
+                connstate->randr_major_opcode = reply->major_opcode;
+            }
+
+            if (sequence == connstate->getmonitors) {
+                printf("RRGetMonitors reply!\n");
+                xcb_randr_get_monitors_reply_t *reply = packet;
+                if (injected_reply != NULL) {
+                    printf("injecting reply\n");
+                    ((generic_x11_reply_t *)injected_reply)->sequence = sequence;
+                    must_write(writeall(connstate->clientw->fd, injected_reply, injected_reply_len));
+                    free(packet);
+                    return;
+                }
+            }
+            /* END RandR 1.5 specific */
+
+            break;
+
+        default:  // event
+            break;
+    }
+    must_write(writeall(connstate->clientw->fd, packet, len));
+    free(packet);
+}
+
+static void child_cb(EV_P_ ev_child *w, int revents) {
+    ev_child_stop(EV_A_ w);
+    if (WIFEXITED(w->rstatus)) {
+        exit(WEXITSTATUS(w->rstatus));
+    } else {
+        exit(WTERMSIG(w->rstatus) + 128);
+    }
+}
+
+static void must_read_reply(const char *filename) {
+    FILE *f;
+    if ((f = fopen(filename, "r")) == NULL) {
+        err(EXIT_FAILURE, "fopen(%s)", filename);
+    }
+    struct stat stbuf;
+    if (fstat(fileno(f), &stbuf) != 0) {
+        err(EXIT_FAILURE, "fstat(%s)", filename);
+    }
+    /* BEGIN RandR 1.5 specific */
+    injected_reply_len = stbuf.st_size;
+    injected_reply = smalloc(stbuf.st_size);
+    int n = fread(injected_reply, 1, stbuf.st_size, f);
+    /* END RandR 1.5 specific */
+    if (n != stbuf.st_size) {
+        err(EXIT_FAILURE, "fread(%s)", filename);
+    }
+    fclose(f);
+}
+
+int main(int argc, char *argv[]) {
+    static struct option long_options[] = {
+        {"getmonitors_reply", required_argument, 0, 0},
+        {0, 0, 0, 0},
+    };
+    char *options_string = "";
+    int opt;
+    int option_index = 0;
+
+    while ((opt = getopt_long(argc, argv, options_string, long_options, &option_index)) != -1) {
+        switch (opt) {
+            case 0:
+                if (strcmp(long_options[option_index].name, "getmonitors_reply") == 0) {
+                    must_read_reply(optarg);
+                }
+                break;
+            default:
+                exit(EXIT_FAILURE);
+        }
+    }
+
+    if (optind >= argc) {
+        errx(EXIT_FAILURE, "syntax: %s [options] <command>\n", argv[0]);
+    }
+
+    int fd = socket(AF_LOCAL, SOCK_STREAM, 0);
+    if (fd == -1) {
+        err(EXIT_FAILURE, "socket(AF_UNIX)");
+    }
+
+    if (fcntl(fd, F_SETFD, FD_CLOEXEC)) {
+        warn("Could not set FD_CLOEXEC");
+    }
+
+    struct sockaddr_un addr;
+    memset(&addr, 0, sizeof(struct sockaddr_un));
+    addr.sun_family = AF_UNIX;
+    int i;
+    bool bound = false;
+    for (i = 0; i < 100; i++) {
+        /* XXX: The path to X11 sockets differs on some platforms (e.g. Trusted
+         * Solaris, HPUX), but since libxcb doesn’t provide a function to
+         * generate the path, we’ll just have to hard-code it for now. */
+        snprintf(addr.sun_path, sizeof(addr.sun_path), "/tmp/.X11-unix/X%d", i);
+
+        if (bind(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_un)) == -1) {
+            warn("bind(%s)", addr.sun_path);
+        } else {
+            bound = true;
+            /* Let the user know bind() was successful, so that they know the
+             * error messages can be disregarded. */
+            fprintf(stderr, "Successfuly bound to %s\n", addr.sun_path);
+            sun_path = sstrdup(addr.sun_path);
+            break;
+        }
+    }
+
+    if (!bound) {
+        err(EXIT_FAILURE, "bind()");
+    }
+
+    atexit(cleanup_socket);
+
+    /* This program will be started for each testcase which requires it, so we
+     * expect precisely one connection. */
+    if (listen(fd, 1) == -1) {
+        err(EXIT_FAILURE, "listen()");
+    }
+
+    pid_t child = fork();
+    if (child == -1) {
+        err(EXIT_FAILURE, "fork()");
+    }
+    if (child == 0) {
+        char *display;
+        sasprintf(&display, ":%d", i);
+        setenv("DISPLAY", display, 1);
+        free(display);
+
+        char **child_args = argv + optind;
+        execvp(child_args[0], child_args);
+        err(EXIT_FAILURE, "exec()");
+    }
+
+    struct ev_loop *loop = ev_default_loop(0);
+
+    ev_child cw;
+    ev_child_init(&cw, child_cb, child, 0);
+    ev_child_start(loop, &cw);
+
+    ev_io watcher;
+    ev_io_init(&watcher, uds_connection_cb, fd, EV_READ);
+    ev_io_start(loop, &watcher);
+
+    ev_run(loop, 0);
+}

testcases/lib/SocketActivation.pm

@@ -88,7 +88,10 @@ sub activate_i3 {
         # the interactive signalhandler to make it crash immediately instead.
         # Also disable logging to SHM since we redirect the logs anyways.
         # Force Xinerama because we use Xdmx for multi-monitor tests.
-        my $i3cmd = q|i3 --shmlog-size=0 --disable-signalhandler --force-xinerama|;
+        my $i3cmd = q|i3 --shmlog-size=0 --disable-signalhandler|;
+        if (!defined($args{inject_randr15})) {
+            $i3cmd .= q| --force-xinerama|;
+        }
         if (!$args{validate_config}) {
             # We only set logging if i3 is actually started, but not if we only
             # validate the config file. This is to keep logging to a minimum as
@@ -139,6 +142,13 @@ sub activate_i3 {
                      'sh -c "export LISTEN_PID=\$\$; ' . $cmd . '"';
         }
 
+        if ($args{inject_randr15}) {
+            # See comment in $args{strace} branch.
+            $cmd = 'test.inject_randr15 --getmonitors_reply="' .
+                   $args{inject_randr15} . '" -- ' .
+                   'sh -c "export LISTEN_PID=\$\$; ' . $cmd . '"';
+        }
+
         # We need to use the shell due to using output redirections.
         exec '/bin/sh', '-c', $cmd;
 

testcases/lib/i3test.pm.in

@@ -861,6 +861,7 @@ sub launch_with_config {
         cv => $cv,
         dont_create_temp_dir => $args{dont_create_temp_dir},
         validate_config => $args{validate_config},
+        inject_randr15 => $args{inject_randr15},
     );
 
     # If we called i3 with -C, we wait for it to exit and then return as

testcases/t/533-randr15.t

@@ -0,0 +1,73 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Please read the following documents before working on tests:
+# • http://build.i3wm.org/docs/testsuite.html
+#   (or docs/testsuite)
+#
+# • http://build.i3wm.org/docs/lib-i3test.html
+#   (alternatively: perldoc ./testcases/lib/i3test.pm)
+#
+# • http://build.i3wm.org/docs/ipc.html
+#   (or docs/ipc)
+#
+# • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
+#   (unless you are already familiar with Perl)
+#
+# TODO: Description of this file.
+# Ticket: #999
+# Bug still in: 4.13-12-g2ff3d9d
+use File::Temp qw(tempfile);
+use i3test i3_autostart => 0;
+
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+
+EOT
+
+my ($outfh, $outname) = tempfile('i3-randr15reply-XXXXXX', UNLINK => 1);
+
+# Prepare a RRGetMonitors reply, see A.2.4 in
+# https://cgit.freedesktop.org/xorg/proto/randrproto/tree/randrproto.txt
+my $reply = pack('cxSLLLLx[LLL]',
+     1, # reply
+     0, # sequence (will be filled in by inject_randr15)
+     # 56 = length($reply) + length($monitor1)
+     # 32 = minimum X11 reply length
+     (56-32) / 4, # length in words
+     0, # timestamp TODO
+     1, # nmonitors
+     0); # noutputs
+
+# Manually intern _NET_CURRENT_DESKTOP as $x->atom will not create atoms if
+# they are not yet interned.
+my $atom_cookie = $x->intern_atom(0, length("DP3"), "DP3");
+my $DP3 = $x->intern_atom_reply($atom_cookie->{sequence})->{atom};
+
+# MONITORINFO is defined in A.1.1 in
+# https://cgit.freedesktop.org/xorg/proto/randrproto/tree/randrproto.txt
+my $monitor1 = pack('LccSssSSLL',
+        $DP3, # name (ATOM)
+        1, # primary
+        1, # automatic
+        0, # ncrtcs
+        0, # x
+        0, # y
+        3840, # width in pixels
+        2160, # height in pixels
+        520, # width in millimeters
+        290); # height in millimeters
+
+print $outfh $reply;
+print $outfh $monitor1;
+
+close($outfh);
+
+my $pid = launch_with_config($config, inject_randr15 => $outname);
+
+cmd 'nop';
+
+exit_gracefully($pid);
+
+done_testing;