client: a standalone binary that connects to a foot --server

client.c

@@ -0,0 +1,130 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <assert.h>
+#include <getopt.h>
+#include <signal.h>
+#include <errno.h>
+
+#include <sys/socket.h>
+#include <linux/un.h>
+
+#define LOG_MODULE "foot-client"
+#include "log.h"
+#include "version.h"
+
+static volatile sig_atomic_t aborted = 0;
+
+static void
+sig_handler(int signo)
+{
+    aborted = 1;
+}
+
+static void
+print_usage(const char *prog_name)
+{
+    printf("Usage: %s [OPTIONS]...\n", prog_name);
+    printf("\n");
+    printf("Options:\n");
+    printf("  -v,--version                show the version number and quit\n");
+}
+
+int
+main(int argc, char *const *argv)
+{
+    int ret = EXIT_FAILURE;
+
+    const char *const prog_name = argv[0];
+
+    while (true) {
+        int c = getopt_long(argc, argv, ":hv", NULL, NULL);
+        if (c == -1)
+            break;
+
+        switch (c) {
+        case 'v':
+            printf("footclient version %s\n", FOOT_VERSION);
+            return EXIT_SUCCESS;
+
+        case 'h':
+            print_usage(prog_name);
+            return EXIT_SUCCESS;
+
+       case ':':
+            fprintf(stderr, "error: -%c: missing required argument\n", optopt);
+            return EXIT_FAILURE;
+
+        case '?':
+            fprintf(stderr, "error: -%c: invalid option\n", optopt);
+            return EXIT_FAILURE;
+        }
+    }
+
+    argc -= optind;
+    argv += optind;
+
+    int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (fd == -1) {
+        LOG_ERRNO("failed to create socket");
+        goto err;
+    }
+
+    bool connected = false;
+    struct sockaddr_un addr = {.sun_family = AF_UNIX};
+
+    const char *xdg_runtime = getenv("XDG_RUNTIME_DIR");
+    if (xdg_runtime != NULL) {
+        snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/foot.sock", xdg_runtime);
+
+        if (connect(fd, (const struct sockaddr *)&addr, sizeof(addr)) == 0)
+            connected = true;
+    }
+
+    if (!connected) {
+        strncpy(addr.sun_path, "/tmp/foot.sock", sizeof(addr.sun_path) - 1);
+        if (connect(fd, (const struct sockaddr *)&addr, sizeof(addr)) < 0) {
+            LOG_ERRNO("failed to connect (is 'foot --server' running?)");
+            goto err;
+        }
+    }
+
+    if (send(fd, &argc, sizeof(argc), 0) != sizeof(argc)) {
+        LOG_ERRNO("failed to send argc/argv to server");
+        goto err;
+    }
+
+    for (int i = 0; i < argc; i++) {
+        uint16_t len = strlen(argv[i]);
+
+        if (send(fd, &len, sizeof(len), 0) != sizeof(len) ||
+            send(fd, argv[i], len, 0) != sizeof(len))
+        {
+            LOG_ERRNO("failed to send argc/argv to server");
+            goto err;
+        }
+    }
+
+    if (sigaction(SIGINT, &(struct sigaction){.sa_handler = &sig_handler}, NULL) < 0) {
+        LOG_ERRNO("failed to register signal handlers");
+        goto err;
+    }
+
+    int exit_code;
+    ssize_t rcvd = recv(fd, &exit_code, sizeof(exit_code), 0);
+
+    if (rcvd == -1 && errno == EINTR)
+        assert(aborted);
+    else if (rcvd != sizeof(exit_code))
+        LOG_ERRNO("failed to read server response");
+    else
+        ret = exit_code;
+
+err:
+    if (fd != -1)
+        close(fd);
+    return ret;
+}

completions/meson.build

@@ -1,2 +1,3 @@
 zsh_install_dir = join_paths(get_option('datadir'), 'zsh/site-functions')
 install_data('zsh/_foot', install_dir: zsh_install_dir)
+install_data('zsh/_footclient', install_dir: zsh_install_dir)

completions/zsh/_footclient

@@ -0,0 +1,6 @@
+#compdef footclient
+
+_arguments \
+    -s \
+    '(-v --version)'{-v,--version}'[show the version number and quit]' \
+    '(-h --help)'{-h,--help}'[show help message and quit]'

meson.build

@@ -90,6 +90,12 @@ executable(
   dependencies: [threads, math, freetype, fontconfig, pixman, wayland_client, wayland_cursor, xkb],
   install: true)
 
+executable(
+  'footclient',
+  'client.c',
+  'log.c', 'log.h',
+  install: true)
+
 custom_target(
   'terminfo',
   output: 'f',