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examples: Add a multiport virtio console example
Add an example which shows the new multiport console functionality with multiple terminals. The example uses tmux to create the the terminals in the background. Signed-off-by: Matej Hrica <[email protected]>
1 parent 20b0c06 commit 6a3e3a1

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3 files changed

+224
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‎.gitignore‎

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@@ -9,4 +9,5 @@ __pycache__
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/libkrun.pc
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init/init
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examples/chroot_vm
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examples/consoles
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test-prefix

‎examples/Makefile‎

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@@ -14,7 +14,7 @@ ROOTFS_DIR = rootfs_$(ROOTFS_DISTRO)
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.PHONY: clean rootfs
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EXAMPLES := chroot_vm external_kernel
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EXAMPLES := chroot_vm external_kernel consoles
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ifeq ($(SEV),1)
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EXAMPLES := launch-tee
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endif
@@ -53,6 +53,9 @@ ifeq ($(OS),Darwin)
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codesign --entitlements chroot_vm.entitlements --force -s - $@
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endif
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consoles: consoles.c
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gcc -o $@ $< $(CFLAGS) $(LDFLAGS_$(ARCH)_$(OS))
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nitro: nitro.c
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gcc -o $@ $< $(CFLAGS) $(LDFLAGS_nitro)
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@@ -64,4 +67,4 @@ rootfs:
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podman rm libkrun_chroot_vm
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clean:
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rm -rf chroot_vm $(ROOTFS_DIR) launch-tee boot_efi external_kernel nitro
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rm -rf chroot_vm $(ROOTFS_DIR) launch-tee boot_efi external_kernel nitro consoles

‎examples/consoles.c‎

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@@ -0,0 +1,218 @@
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdarg.h>
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#include <sys/wait.h>
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#include <sys/stat.h>
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#include <libkrun.h>
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static int cmd_output(char *output, size_t output_size, const char *prog, ...)
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{
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va_list args;
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const char *argv[32];
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int argc = 0;
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int pipe_fds[2] = { -1, -1 };
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argv[argc++] = prog;
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va_start(args, prog);
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while (argc < 31) {
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const char *arg = va_arg(args, const char *);
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argv[argc++] = arg;
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if (arg == NULL) break;
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}
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va_end(args);
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argv[argc] = NULL;
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if (output && output_size > 0) {
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if (pipe(pipe_fds) < 0) return -1;
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}
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pid_t pid = fork();
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if (pid < 0) return -1;
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if (pid == 0) {
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if (pipe_fds[0] >= 0) {
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close(pipe_fds[0]);
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dup2(pipe_fds[1], STDOUT_FILENO);
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close(pipe_fds[1]);
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}
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execvp(prog, (char *const *)argv);
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_exit(127);
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}
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if (pipe_fds[0] >= 0) {
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close(pipe_fds[1]);
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ssize_t n = read(pipe_fds[0], output, output_size - 1);
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close(pipe_fds[0]);
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if (n < 0) n = 0;
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output[n] = '\0';
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}
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int status;
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if (waitpid(pid, &status, 0) < 0) return -1;
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if (!WIFEXITED(status)) return -1;
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return WEXITSTATUS(status);
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}
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#define cmd(...) ({ char _d[1]; cmd_output(_d, 0, __VA_ARGS__); })
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static int create_tmux_tty(const char *session_name)
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{
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char tty_path[256];
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char wait_cmd[128];
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snprintf(wait_cmd, sizeof(wait_cmd), "tail --pid=%d -f /dev/null", (int)getpid());
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if (cmd("tmux", "new-session", "-d", "-s", session_name, "sh", "-c", wait_cmd, NULL) != 0)
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return -1;
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// Hook up tmux to send us SIGWINCH signal on resize
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char hook_cmd[128];
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snprintf(hook_cmd, sizeof(hook_cmd), "run-shell 'kill -WINCH %d'", (int)getpid());
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cmd("tmux", "set-hook", "-g", "client-resized", hook_cmd, NULL);
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if (cmd_output(tty_path, sizeof(tty_path), "tmux", "display-message", "-p", "-t", session_name, "#{pane_tty}", NULL) != 0)
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return -1;
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tty_path[strcspn(tty_path, "\n")] = '\0';
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int fd = open(tty_path, O_RDWR);
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if (fd < 0) return -1;
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return fd;
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}
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static int mkfifo_if_needed(const char *path)
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{
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if (mkfifo(path, 0666) < 0) {
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if (errno != EEXIST) return -1;
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}
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return 0;
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}
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static int create_fifo_inout(const char *fifo_in, const char *fifo_out, int *input_fd, int *output_fd)
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{
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if (mkfifo_if_needed(fifo_in) < 0) return -1;
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if (mkfifo_if_needed(fifo_out) < 0) return -1;
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int in_fd = open(fifo_in, O_RDONLY | O_NONBLOCK);
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if (in_fd < 0) return -1;
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int out_fd = open(fifo_out, O_RDWR | O_NONBLOCK);
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if (out_fd < 0) { close(in_fd); return -1; }
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*input_fd = in_fd;
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*output_fd = out_fd;
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return 0;
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}
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int main(int argc, char *const argv[])
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{
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if (argc < 3) {
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fprintf(stderr, "Usage: %s ROOT_DIR COMMAND [ARGS...]\n", argv[0]);
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return 1;
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}
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const char *root_dir = argv[1];
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const char *command = argv[2];
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const char *const *command_args = (argc > 3) ? (const char *const *)&argv[3] : NULL;
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const char *const envp[] = { 0 };
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krun_set_log_level(KRUN_LOG_LEVEL_WARN);
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int err;
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int ctx_id = krun_create_ctx();
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if (ctx_id < 0) { errno = -ctx_id; perror("krun_create_ctx"); return 1; }
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if ((err = krun_disable_implicit_console(ctx_id))) {
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errno = -err;
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perror("krun_disable_implicit_console");
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return 1;
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}
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int console_id = krun_add_virtio_console_multiport(ctx_id);
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if (console_id < 0) {
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errno = -console_id;
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perror("krun_add_virtio_console_multiport");
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return 1;
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}
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/* Configure console ports - edit this section to add/remove ports */
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{
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// You could also use the controlling terminal of this process in the guest:
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/*
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if ((err = krun_add_console_port_tty(ctx_id, console_id, "host_tty", open("/dev/tty", O_RDWR)))) {
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errno = -err;
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perror("port host_tty");
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return 1;
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}
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*/
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int num_consoles = 3;
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for (int i = 0; i < num_consoles; i++) {
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char session_name[64];
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char port_name[64];
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snprintf(session_name, sizeof(session_name), "krun-console-%d", i + 1);
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snprintf(port_name, sizeof(port_name), "console-%d", i + 1);
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int tmux_fd = create_tmux_tty(session_name);
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if (tmux_fd < 0) {
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perror("create_tmux_tty");
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return 1;
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}
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if ((err = krun_add_console_port_tty(ctx_id, console_id, port_name, tmux_fd))) {
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errno = -err;
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perror("krun_add_console_port_tty");
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return 1;
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}
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}
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int in_fd, out_fd;
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if (create_fifo_inout("/tmp/consoles_example_in", "/tmp/consoles_example_out", &in_fd, &out_fd) < 0) {
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perror("create_fifo_inout");
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return 1;
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}
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if ((err = krun_add_console_port_inout(ctx_id, console_id, "fifo_inout", in_fd, out_fd))) {
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errno = -err;
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perror("krun_add_console_port_inout");
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return 1;
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}
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fprintf(stderr, "\n=== Console ports configured ===\n");
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for (int i = 0; i < num_consoles; i++) {
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fprintf(stderr, " console-%d: tmux attach -t krun-console-%d\n", i + 1, i + 1);
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}
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fprintf(stderr, " fifo_inout: /tmp/consoles_example_in (host->guest)\n");
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fprintf(stderr, " fifo_inout: /tmp/consoles_example_out (guest->host)\n");
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fprintf(stderr, "================================\n\n");
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}
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if ((err = krun_set_vm_config(ctx_id, 4, 4096))) {
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errno = -err;
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perror("krun_set_vm_config");
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return 1;
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}
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if ((err = krun_set_root(ctx_id, root_dir))) {
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errno = -err;
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perror("krun_set_root");
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return 1;
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}
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if ((err = krun_set_exec(ctx_id, command, command_args, envp))) {
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errno = -err;
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perror("krun_set_exec");
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return 1;
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}
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if ((err = krun_start_enter(ctx_id))) {
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errno = -err;
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perror("krun_start_enter");
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return 1;
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}
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return 0;
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}
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