Introduce --timelog=FILE flag to GNU Make

third_party/make/timelog.c

@@ -0,0 +1,186 @@
+/* Copyright 2024 Justine Alexandra Roberts Tunney
+
+   Permission to use, copy, modify, and/or distribute this software for
+   any purpose with or without fee is hereby granted, provided that the
+   above copyright notice and this permission notice appear in all copies.
+
+   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+   AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+   DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+   PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+   TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+   PERFORMANCE OF THIS SOFTWARE.  */
+
+#include "timelog.h"
+
+#include <time.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/uio.h>
+
+struct timelog
+  {
+    struct timespec started;
+    size_t command_length;
+    char command[4000];
+  };
+
+char *timelog_path;
+int timelog_fd = -1;
+
+void timelog_init (void)
+{
+  if (!timelog_path)
+    return;
+  if ((timelog_fd = open (timelog_path, O_APPEND | O_WRONLY | O_CREAT, 0644)) == -1)
+    {
+      perror (timelog_path);
+      exit (1);
+    }
+}
+
+static int is_shell_safe (int c)
+{
+  if (c > 127)
+    return true;
+  if (isalnum(c))
+    return true;
+  switch (c)
+    {
+    case '+':
+    case '-':
+    case '.':
+    case '/':
+    case '_':
+    case '=':
+    case ':':
+      return true;
+    default:
+      return false;
+    }
+}
+
+static int needs_quotes (const char *s)
+{
+  int c;
+  if (!*s)
+    return true;
+  while ((c = *s++ & 255))
+    if (!is_shell_safe (c))
+      return true;
+  return false;
+}
+
+static long long get_microseconds (struct timespec beg, struct timespec end)
+{
+  end.tv_sec -= beg.tv_sec;
+  if (end.tv_nsec < beg.tv_nsec)
+    {
+      end.tv_nsec += 1000000000;
+      end.tv_sec--;
+    }
+  end.tv_nsec -= beg.tv_nsec;
+  return end.tv_sec * 1000000ll + end.tv_nsec / 1000ll;
+}
+
+struct timelog *timelog_begin (char **argv)
+{
+  int i, j, q;
+  char *p, *pe;
+
+  /* don't bother if disabled */
+  if (timelog_fd == -1)
+    return NULL;
+
+  /* allocate object */
+  struct timelog *tl;
+  if (!(tl = malloc (sizeof (struct timelog))))
+    return NULL;
+
+  /* stringify command */
+  p = tl->command;
+  pe = tl->command + sizeof (tl->command) - 1;
+  for (i = 0; argv[i]; ++i)
+    {
+      if (i && p < pe)
+        *p++ = ' ';
+      q = needs_quotes (argv[i]);
+      if (q && p < pe)
+        *p++ = '\'';
+      for (j = 0; argv[i][j]; ++j)
+        {
+          if (isspace(argv[i][j]) ||
+              iscntrl(argv[i][j]))
+            {
+              if (p < pe)
+                *p++ = ' ';
+            }
+          else if (argv[i][j] == '\'')
+            {
+              if (p < pe)
+                *p++ = '\'';
+              if (p < pe)
+                *p++ = '"';
+              if (p < pe)
+                *p++ = '\'';
+              if (p < pe)
+                *p++ = '"';
+              if (p < pe)
+                *p++ = '\'';
+            }
+          else
+            {
+              if (p < pe)
+                *p++ = argv[i][j];
+            }
+        }
+      if (q && p < pe)
+        *p++ = '\'';
+    }
+  if (p == pe)
+    {
+      p[-3] = '.';
+      p[-2] = '.';
+      p[-1] = '.';
+    }
+  *p++ = '\n';
+  tl->command_length = p - tl->command;
+
+  /* record starting timestamp */
+  clock_gettime (CLOCK_REALTIME, &tl->started);
+
+  /* return object */
+  return tl;
+}
+
+void timelog_end (struct timelog *tl)
+{
+  long long us;
+  char ibuf[22];
+  struct iovec iov[2];
+  struct timespec ended;
+
+  /* don't bother if disabled */
+  if (tl == NULL)
+    return;
+
+  /* get elapsed microseconds string */
+  clock_gettime (CLOCK_REALTIME, &ended);
+  us = get_microseconds (tl->started, ended);
+  snprintf (ibuf, sizeof(ibuf), "% 20lld ", us);
+
+  // write to log
+  iov[0].iov_base = ibuf;
+  iov[0].iov_len = 21;
+  iov[1].iov_base = tl->command;
+  iov[1].iov_len = tl->command_length;
+  writev (timelog_fd, iov, 2);
+
+  // free object
+  free (tl);
+}