1 files changed, 286 insertions, 0 deletions
diff --git a/src/nvim/os/proc.c b/src/nvim/os/proc.c
new file mode 100644
index 0000000000..053f5f3ba0
--- /dev/null
+++ b/src/nvim/os/proc.c
@@ -0,0 +1,286 @@
+/// OS process functions
+///
+/// psutil is a good reference for cross-platform syscall voodoo:
+/// https://github.com/giampaolo/psutil/tree/master/psutil/arch
+
+// IWYU pragma: no_include <sys/param.h>
+
+#include <assert.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <uv.h>
+
+#ifdef MSWIN
+# include <tlhelp32.h>
+#endif
+
+#if defined(__FreeBSD__)
+# include <string.h>
+# include <sys/types.h>
+# include <sys/user.h>
+#endif
+
+#if defined(__NetBSD__) || defined(__OpenBSD__)
+# include <sys/param.h>
+#endif
+
+#if defined(__APPLE__) || defined(BSD)
+# include <sys/sysctl.h>
+
+# include "nvim/macros_defs.h"
+#endif
+
+#if defined(__linux__)
+# include <stdio.h>
+#endif
+
+#include "nvim/log.h"
+#include "nvim/memory.h"
+#include "nvim/os/proc.h"
+
+#ifdef MSWIN
+# include "nvim/api/private/helpers.h"
+#endif
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "os/proc.c.generated.h"
+#endif
+
+#ifdef MSWIN
+static bool os_proc_tree_kill_rec(HANDLE proc, int sig)
+{
+  if (proc == NULL) {
+    return false;
+  }
+  PROCESSENTRY32 pe;
+  DWORD pid = GetProcessId(proc);
+
+  if (pid != 0) {
+    HANDLE h = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+    if (h != INVALID_HANDLE_VALUE) {
+      pe.dwSize = sizeof(PROCESSENTRY32);
+      if (!Process32First(h, &pe)) {
+        goto theend;
+      }
+      do {
+        if (pe.th32ParentProcessID == pid) {
+          HANDLE ph = OpenProcess(PROCESS_ALL_ACCESS, false, pe.th32ProcessID);
+          if (ph != NULL) {
+            os_proc_tree_kill_rec(ph, sig);
+            CloseHandle(ph);
+          }
+        }
+      } while (Process32Next(h, &pe));
+      CloseHandle(h);
+    }
+  }
+
+theend:
+  return (bool)TerminateProcess(proc, (unsigned)sig);
+}
+/// Kills process `pid` and its descendants recursively.
+bool os_proc_tree_kill(int pid, int sig)
+{
+  assert(sig >= 0);
+  assert(sig == SIGTERM || sig == SIGKILL);
+  if (pid > 0) {
+    ILOG("terminating process tree: %d", pid);
+    HANDLE h = OpenProcess(PROCESS_ALL_ACCESS, false, (DWORD)pid);
+    return os_proc_tree_kill_rec(h, sig);
+  } else {
+    ELOG("invalid pid: %d", pid);
+  }
+  return false;
+}
+#else
+/// Kills process group where `pid` is the process group leader.
+bool os_proc_tree_kill(int pid, int sig)
+{
+  assert(sig == SIGTERM || sig == SIGKILL);
+  if (pid == 0) {
+    // Never kill self (pid=0).
+    return false;
+  }
+  ILOG("sending %s to PID %d", sig == SIGTERM ? "SIGTERM" : "SIGKILL", -pid);
+  return uv_kill(-pid, sig) == 0;
+}
+#endif
+
+/// Gets the process ids of the immediate children of process `ppid`.
+///
+/// @param ppid Process to inspect.
+/// @param[out,allocated] proc_list Child process ids.
+/// @param[out] proc_count Number of child processes.
+/// @return 0 on success, 1 if process not found, 2 on other error.
+int os_proc_children(int ppid, int **proc_list, size_t *proc_count)
+  FUNC_ATTR_NONNULL_ALL
+{
+  if (ppid < 0) {
+    return 2;
+  }
+
+  int *temp = NULL;
+  *proc_list = NULL;
+  *proc_count = 0;
+
+#ifdef MSWIN
+  PROCESSENTRY32 pe;
+
+  // Snapshot of all processes.
+  HANDLE h = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+  if (h == INVALID_HANDLE_VALUE) {
+    return 2;
+  }
+
+  pe.dwSize = sizeof(PROCESSENTRY32);
+  // Get root process.
+  if (!Process32First(h, &pe)) {
+    CloseHandle(h);
+    return 2;
+  }
+  // Collect processes whose parent matches `ppid`.
+  do {
+    if (pe.th32ParentProcessID == (DWORD)ppid) {
+      temp = xrealloc(temp, (*proc_count + 1) * sizeof(*temp));
+      temp[*proc_count] = (int)pe.th32ProcessID;
+      (*proc_count)++;
+    }
+  } while (Process32Next(h, &pe));
+  CloseHandle(h);
+
+#elif defined(__APPLE__) || defined(BSD)
+# if defined(__APPLE__)
+#  define KP_PID(o) o.kp_proc.p_pid
+#  define KP_PPID(o) o.kp_eproc.e_ppid
+# elif defined(__FreeBSD__)
+#  define KP_PID(o) o.ki_pid
+#  define KP_PPID(o) o.ki_ppid
+# else
+#  define KP_PID(o) o.p_pid
+#  define KP_PPID(o) o.p_ppid
+# endif
+# ifdef __NetBSD__
+  static int name[] = {
+    CTL_KERN, KERN_PROC2, KERN_PROC_ALL, 0, (int)(sizeof(struct kinfo_proc2)), 0
+  };
+# else
+  static int name[] = { CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0 };
+# endif
+
+  // Get total process count.
+  size_t len = 0;
+  int rv = sysctl(name, ARRAY_SIZE(name) - 1, NULL, &len, NULL, 0);
+  if (rv) {
+    return 2;
+  }
+
+  // Get ALL processes.
+# ifdef __NetBSD__
+  struct kinfo_proc2 *p_list = xmalloc(len);
+# else
+  struct kinfo_proc *p_list = xmalloc(len);
+# endif
+  rv = sysctl(name, ARRAY_SIZE(name) - 1, p_list, &len, NULL, 0);
+  if (rv) {
+    xfree(p_list);
+    return 2;
+  }
+
+  // Collect processes whose parent matches `ppid`.
+  bool exists = false;
+  size_t p_count = len / sizeof(*p_list);
+  for (size_t i = 0; i < p_count; i++) {
+    exists = exists || KP_PID(p_list[i]) == ppid;
+    if (KP_PPID(p_list[i]) == ppid) {
+      temp = xrealloc(temp, (*proc_count + 1) * sizeof(*temp));
+      temp[*proc_count] = KP_PID(p_list[i]);
+      (*proc_count)++;
+    }
+  }
+  xfree(p_list);
+  if (!exists) {
+    return 1;  // Process not found.
+  }
+
+#elif defined(__linux__)
+  char proc_p[256] = { 0 };
+  // Collect processes whose parent matches `ppid`.
+  // Rationale: children are defined in thread with same ID of process.
+  snprintf(proc_p, sizeof(proc_p), "/proc/%d/task/%d/children", ppid, ppid);
+  FILE *fp = fopen(proc_p, "r");
+  if (fp == NULL) {
+    return 2;  // Process not found, or /proc/…/children not supported.
+  }
+  int match_pid;
+  while (fscanf(fp, "%d", &match_pid) > 0) {
+    temp = xrealloc(temp, (*proc_count + 1) * sizeof(*temp));
+    temp[*proc_count] = match_pid;
+    (*proc_count)++;
+  }
+  fclose(fp);
+#endif
+
+  *proc_list = temp;
+  return 0;
+}
+
+#ifdef MSWIN
+/// Gets various properties of the process identified by `pid`.
+///
+/// @param pid Process to inspect.
+/// @return Map of process properties, empty on error.
+Dict os_proc_info(int pid, Arena *arena)
+{
+  Dict pinfo = ARRAY_DICT_INIT;
+  PROCESSENTRY32 pe;
+
+  // Snapshot of all processes.  This is used instead of:
+  //    OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, …)
+  // to avoid ERROR_PARTIAL_COPY.  https://stackoverflow.com/a/29942376
+  HANDLE h = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+  if (h == INVALID_HANDLE_VALUE) {
+    return pinfo;  // Return empty.
+  }
+
+  pe.dwSize = sizeof(PROCESSENTRY32);
+  // Get root process.
+  if (!Process32First(h, &pe)) {
+    CloseHandle(h);
+    return pinfo;  // Return empty.
+  }
+  // Find the process.
+  do {
+    if (pe.th32ProcessID == (DWORD)pid) {
+      break;
+    }
+  } while (Process32Next(h, &pe));
+  CloseHandle(h);
+
+  if (pe.th32ProcessID == (DWORD)pid) {
+    pinfo = arena_dict(arena, 3);
+    PUT_C(pinfo, "pid", INTEGER_OBJ(pid));
+    PUT_C(pinfo, "ppid", INTEGER_OBJ((int)pe.th32ParentProcessID));
+    PUT_C(pinfo, "name", CSTR_TO_ARENA_OBJ(arena, pe.szExeFile));
+  }
+
+  return pinfo;
+}
+#endif
+
+/// Return true if process `pid` is running.
+bool os_proc_running(int pid)
+{
+  int err = uv_kill(pid, 0);
+  // If there is no error the process must be running.
+  if (err == 0) {
+    return true;
+  }
+  // If the error is ESRCH then the process is not running.
+  if (err == UV_ESRCH) {
+    return false;
+  }
+  // If the process is running and owned by another user we get EPERM.  With
+  // other errors the process might be running, assuming it is then.
+  return true;
+}