job: Allow spawning jobs connected to pseudo terminals

5 files changed, 272 insertions, 5 deletions

diff --git a/src/nvim/os/job.c b/src/nvim/os/job.c
index 94bb9067ed..9855a19269 100644
--- a/src/nvim/os/job.c
+++ b/src/nvim/os/job.c
@@ -7,6 +7,7 @@
 #include "nvim/os/job.h"
 #include "nvim/os/job_defs.h"
 #include "nvim/os/job_private.h"
+#include "nvim/os/pty_process.h"
 #include "nvim/os/rstream.h"
 #include "nvim/os/rstream_defs.h"
 #include "nvim/os/wstream.h"
@@ -320,6 +321,16 @@ void *job_data(Job *job)
   return job->opts.data;
 }
 
+/// Resize the window for a pty job
+bool job_resize(Job *job, uint16_t width, uint16_t height)
+{
+  if (!job->opts.pty) {
+    return false;
+  }
+  pty_process_resize(job, width, height);
+  return true;
+}
+
 /// Iterates the table, sending SIGTERM to stopped jobs and SIGKILL to those
 /// that didn't die from SIGTERM after a while(exit_timeout is 0).
 static void job_stop_timer_cb(uv_timer_t *handle)
diff --git a/src/nvim/os/job_defs.h b/src/nvim/os/job_defs.h
index 340ef551be..ac9a37b366 100644
--- a/src/nvim/os/job_defs.h
+++ b/src/nvim/os/job_defs.h
@@ -37,6 +37,13 @@ typedef struct {
   job_exit_cb exit_cb;
   // Maximum memory used by the job's WStream
   size_t maxmem;
+  // Connect the job to a pseudo terminal
+  bool pty;
+  // Initial window dimensions if the job is connected to a pseudo terminal
+  uint16_t width, height;
+  // Value for the $TERM environment variable. A default value of "ansi" is
+  // assumed if NULL
+  char *term_name;
 } JobOptions;
 
 #define JOB_OPTIONS_INIT ((JobOptions) {                     \
@@ -46,6 +53,10 @@ typedef struct {
     .stdout_cb = NULL,                                       \
     .stderr_cb = NULL,                                       \
     .exit_cb = NULL,                                         \
-    .maxmem = 0                                              \
+    .maxmem = 0,                                             \
+    .pty = false,                                            \
+    .width = 80,                                             \
+    .height = 24,                                            \
+    .term_name = NULL                                        \
     })
 #endif  // NVIM_OS_JOB_DEFS_H
diff --git a/src/nvim/os/job_private.h b/src/nvim/os/job_private.h
index 1beaa1bd70..b1d5e13feb 100644
--- a/src/nvim/os/job_private.h
+++ b/src/nvim/os/job_private.h
@@ -8,6 +8,7 @@
 #include "nvim/os/rstream_defs.h"
 #include "nvim/os/wstream_defs.h"
 #include "nvim/os/pipe_process.h"
+#include "nvim/os/pty_process.h"
 #include "nvim/os/shell.h"
 #include "nvim/log.h"
 
@@ -45,12 +46,16 @@ extern uv_timer_t job_stop_timer;
 
 static inline bool process_spawn(Job *job)
 {
-  return pipe_process_spawn(job);
+  return job->opts.pty ? pty_process_spawn(job) : pipe_process_spawn(job);
 }
 
 static inline void process_init(Job *job)
 {
-  pipe_process_init(job);
+  if (job->opts.pty) {
+    pty_process_init(job);
+  } else {
+    pipe_process_init(job);
+  }
 }
 
 static inline void process_close(Job *job)
@@ -59,12 +64,20 @@ static inline void process_close(Job *job)
     return;
   }
   job->closed = true;
-  pipe_process_close(job);
+  if (job->opts.pty) {
+    pty_process_close(job);
+  } else {
+    pipe_process_close(job);
+  }
 }
 
 static inline void process_destroy(Job *job)
 {
-  pipe_process_destroy(job);
+  if (job->opts.pty) {
+    pty_process_destroy(job);
+  } else {
+    pipe_process_destroy(job);
+  }
 }
 
 static inline void job_exit_callback(Job *job)
diff --git a/src/nvim/os/pty_process.c b/src/nvim/os/pty_process.c
new file mode 100644
index 0000000000..bd7247c741
--- /dev/null
+++ b/src/nvim/os/pty_process.c
@@ -0,0 +1,225 @@
+// Some of the code came from pangoterm and libuv
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <unistd.h>
+#include <termios.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/ioctl.h>
+
+// forkpty is not in POSIX, so headers are platform-specific
+#if defined(__FreeBSD__)
+# include <libutil.h>
+#elif defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
+# include <util.h>
+#else
+# include <pty.h>
+#endif
+
+#include <uv.h>
+
+#include "nvim/os/job.h"
+#include "nvim/os/job_defs.h"
+#include "nvim/os/job_private.h"
+#include "nvim/os/pty_process.h"
+#include "nvim/memory.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "os/pty_process.c.generated.h"
+#endif
+
+typedef struct {
+  struct winsize winsize;
+  uv_pipe_t proc_stdin, proc_stdout, proc_stderr;
+  uv_signal_t schld;
+  int tty_fd;
+} PtyProcess;
+
+void pty_process_init(Job *job)
+{
+  PtyProcess *ptyproc = xmalloc(sizeof(PtyProcess));
+
+  if (job->opts.writable) {
+    uv_pipe_init(uv_default_loop(), &ptyproc->proc_stdin, 0);
+    ptyproc->proc_stdin.data = NULL;
+  }
+
+  if (job->opts.stdout_cb) {
+    uv_pipe_init(uv_default_loop(), &ptyproc->proc_stdout, 0);
+    ptyproc->proc_stdout.data = NULL;
+  }
+
+  if (job->opts.stderr_cb) {
+    uv_pipe_init(uv_default_loop(), &ptyproc->proc_stderr, 0);
+    ptyproc->proc_stderr.data = NULL;
+  }
+
+  job->proc_stdin = (uv_stream_t *)&ptyproc->proc_stdin;
+  job->proc_stdout = (uv_stream_t *)&ptyproc->proc_stdout;
+  job->proc_stderr = (uv_stream_t *)&ptyproc->proc_stderr;
+  job->process = ptyproc;
+}
+
+void pty_process_destroy(Job *job)
+{
+  free(job->opts.term_name);
+  free(job->process);
+  job->process = NULL;
+}
+
+bool pty_process_spawn(Job *job)
+{
+  int master;
+  PtyProcess *ptyproc = job->process;
+  ptyproc->winsize = (struct winsize){job->opts.height, job->opts.width, 0, 0};
+  struct termios termios;
+  init_termios(&termios);
+  uv_disable_stdio_inheritance();
+
+  int pid = forkpty(&master, NULL, &termios, &ptyproc->winsize);
+
+  if (pid < 0) {
+    return false;
+  } else if (pid == 0) {
+    init_child(job);
+    abort();
+  }
+
+  // make sure the master file descriptor is non blocking
+  fcntl(master, F_SETFL, fcntl(master, F_GETFL) | O_NONBLOCK);
+
+  if (job->opts.writable) {
+    uv_pipe_open(&ptyproc->proc_stdin, dup(master));
+  }
+
+  if (job->opts.stdout_cb) {
+    uv_pipe_open(&ptyproc->proc_stdout, dup(master));
+  }
+
+  if (job->opts.stderr_cb) {
+    uv_pipe_open(&ptyproc->proc_stderr, dup(master));
+  }
+
+  uv_signal_init(uv_default_loop(), &ptyproc->schld);
+  uv_signal_start(&ptyproc->schld, chld_handler, SIGCHLD);
+  ptyproc->schld.data = job;
+  ptyproc->tty_fd = master;
+  job->pid = pid;
+  return true;
+}
+
+void pty_process_close(Job *job)
+{
+  PtyProcess *ptyproc = job->process;
+  uv_signal_stop(&ptyproc->schld);
+  uv_close((uv_handle_t *)&ptyproc->schld, NULL);
+  job_close_streams(job);
+  job_decref(job);
+}
+
+void pty_process_resize(Job *job, uint16_t width, uint16_t height)
+{
+  PtyProcess *ptyproc = job->process;
+  ptyproc->winsize = (struct winsize){height, width, 0, 0};
+  ioctl(ptyproc->tty_fd, TIOCSWINSZ, &ptyproc->winsize);
+}
+
+static void init_child(Job *job)
+{
+  unsetenv("COLUMNS");
+  unsetenv("LINES");
+  unsetenv("TERMCAP");
+  unsetenv("COLORTERM");
+  unsetenv("COLORFGBG");
+
+  signal(SIGCHLD, SIG_DFL);
+  signal(SIGHUP, SIG_DFL);
+  signal(SIGINT, SIG_DFL);
+  signal(SIGQUIT, SIG_DFL);
+  signal(SIGTERM, SIG_DFL);
+  signal(SIGALRM, SIG_DFL);
+
+  setenv("TERM", job->opts.term_name ? job->opts.term_name : "ansi", 1);
+  execvp(job->opts.argv[0], job->opts.argv);
+  fprintf(stderr, "execvp failed: %s\n", strerror(errno));
+}
+
+static void chld_handler(uv_signal_t *handle, int signum)
+{
+  Job *job = handle->data;
+  int stat = 0;
+
+  if (waitpid(job->pid, &stat, 0) < 0) {
+    fprintf(stderr, "Waiting for pid %d failed: %s\n", job->pid,
+        strerror(errno));
+    return;
+  }
+
+  if (WIFSTOPPED(stat) || WIFCONTINUED(stat)) {
+    // Did not exit
+    return;
+  }
+
+  if (WIFEXITED(stat)) {
+    job->status = WEXITSTATUS(stat);
+  } else if (WIFSIGNALED(stat)) {
+    job->status = WTERMSIG(stat);
+  }
+
+  pty_process_close(job);
+}
+
+static void init_termios(struct termios *termios)
+{
+  memset(termios, 0, sizeof(struct termios));
+  // Taken from pangoterm
+  termios->c_iflag = ICRNL|IXON;
+  termios->c_oflag = OPOST|ONLCR|TAB0;
+  termios->c_cflag = CS8|CREAD;
+  termios->c_lflag = ISIG|ICANON|IEXTEN|ECHO|ECHOE|ECHOK;
+
+  cfsetspeed(termios, 38400);
+
+#ifdef IUTF8
+  termios->c_iflag |= IUTF8;
+#endif
+#ifdef NL0
+  termios->c_oflag |= NL0;
+#endif
+#ifdef CR0
+  termios->c_oflag |= CR0;
+#endif
+#ifdef BS0
+  termios->c_oflag |= BS0;
+#endif
+#ifdef VT0
+  termios->c_oflag |= VT0;
+#endif
+#ifdef FF0
+  termios->c_oflag |= FF0;
+#endif
+#ifdef ECHOCTL
+  termios->c_lflag |= ECHOCTL;
+#endif
+#ifdef ECHOKE
+  termios->c_lflag |= ECHOKE;
+#endif
+
+  termios->c_cc[VINTR]    = 0x1f & 'C';
+  termios->c_cc[VQUIT]    = 0x1f & '\\';
+  termios->c_cc[VERASE]   = 0x7f;
+  termios->c_cc[VKILL]    = 0x1f & 'U';
+  termios->c_cc[VEOF]     = 0x1f & 'D';
+  termios->c_cc[VEOL]     = _POSIX_VDISABLE;
+  termios->c_cc[VEOL2]    = _POSIX_VDISABLE;
+  termios->c_cc[VSTART]   = 0x1f & 'Q';
+  termios->c_cc[VSTOP]    = 0x1f & 'S';
+  termios->c_cc[VSUSP]    = 0x1f & 'Z';
+  termios->c_cc[VREPRINT] = 0x1f & 'R';
+  termios->c_cc[VWERASE]  = 0x1f & 'W';
+  termios->c_cc[VLNEXT]   = 0x1f & 'V';
+  termios->c_cc[VMIN]     = 1;
+  termios->c_cc[VTIME]    = 0;
+}
diff --git a/src/nvim/os/pty_process.h b/src/nvim/os/pty_process.h
new file mode 100644
index 0000000000..62fcd1671f
--- /dev/null
+++ b/src/nvim/os/pty_process.h
@@ -0,0 +1,7 @@
+#ifndef NVIM_OS_PTY_PROCESS_H
+#define NVIM_OS_PTY_PROCESS_H
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "os/pty_process.h.generated.h"
+#endif
+#endif  // NVIM_OS_PTY_PROCESS_H