1 files changed, 292 insertions, 0 deletions
diff --git a/elf/dl-printf.c b/elf/dl-printf.c
new file mode 100644
index 0000000000..d3264ba96c
--- /dev/null
+++ b/elf/dl-printf.c
@@ -0,0 +1,292 @@
+/* printf implementation for the dynamic loader.
+   Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <_itoa.h>
+#include <assert.h>
+#include <dl-writev.h>
+#include <ldsodefs.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+/* Bare-bones printf implementation.  This function only knows about
+   the formats and flags needed and can handle only up to 64 stripes in
+   the output.  */
+static void
+_dl_debug_vdprintf (int fd, int tag_p, const char *fmt, va_list arg)
+{
+# define NIOVMAX 64
+  struct iovec iov[NIOVMAX];
+  int niov = 0;
+  pid_t pid = 0;
+  char pidbuf[12];
+
+  while (*fmt != '\0')
+    {
+      const char *startp = fmt;
+
+      if (tag_p > 0)
+	{
+	  /* Generate the tag line once.  It consists of the PID and a
+	     colon followed by a tab.  */
+	  if (pid == 0)
+	    {
+	      char *p;
+	      pid = __getpid ();
+	      assert (pid >= 0 && sizeof (pid_t) <= 4);
+	      p = _itoa (pid, &pidbuf[10], 10, 0);
+	      while (p > pidbuf)
+		*--p = ' ';
+	      pidbuf[10] = ':';
+	      pidbuf[11] = '\t';
+	    }
+
+	  /* Append to the output.  */
+	  assert (niov < NIOVMAX);
+	  iov[niov].iov_len = 12;
+	  iov[niov++].iov_base = pidbuf;
+
+	  /* No more tags until we see the next newline.  */
+	  tag_p = -1;
+	}
+
+      /* Skip everything except % and \n (if tags are needed).  */
+      while (*fmt != '\0' && *fmt != '%' && (! tag_p || *fmt != '\n'))
+	++fmt;
+
+      /* Append constant string.  */
+      assert (niov < NIOVMAX);
+      if ((iov[niov].iov_len = fmt - startp) != 0)
+	iov[niov++].iov_base = (char *) startp;
+
+      if (*fmt == '%')
+	{
+	  /* It is a format specifier.  */
+	  char fill = ' ';
+	  int width = -1;
+	  int prec = -1;
+#if LONG_MAX != INT_MAX
+	  int long_mod = 0;
+#endif
+
+	  /* Recognize zero-digit fill flag.  */
+	  if (*++fmt == '0')
+	    {
+	      fill = '0';
+	      ++fmt;
+	    }
+
+	  /* See whether with comes from a parameter.  Note that no other
+	     way to specify the width is implemented.  */
+	  if (*fmt == '*')
+	    {
+	      width = va_arg (arg, int);
+	      ++fmt;
+	    }
+
+	  /* Handle precision.  */
+	  if (*fmt == '.' && fmt[1] == '*')
+	    {
+	      prec = va_arg (arg, int);
+	      fmt += 2;
+	    }
+
+	  /* Recognize the l modifier.  It is only important on some
+	     platforms where long and int have a different size.  We
+	     can use the same code for size_t.  */
+	  if (*fmt == 'l' || *fmt == 'Z')
+	    {
+#if LONG_MAX != INT_MAX
+	      long_mod = 1;
+#endif
+	      ++fmt;
+	    }
+
+	  switch (*fmt)
+	    {
+	      /* Integer formatting.  */
+	    case 'd':
+	    case 'u':
+	    case 'x':
+	      {
+		/* We have to make a difference if long and int have a
+		   different size.  */
+#if LONG_MAX != INT_MAX
+		unsigned long int num = (long_mod
+					 ? va_arg (arg, unsigned long int)
+					 : va_arg (arg, unsigned int));
+#else
+		unsigned long int num = va_arg (arg, unsigned int);
+#endif
+		bool negative = false;
+		if (*fmt == 'd')
+		  {
+#if LONG_MAX != INT_MAX
+		    if (long_mod)
+		      {
+			if ((long int) num < 0)
+			  negative = true;
+		      }
+		    else
+		      {
+			if ((int) num < 0)
+			  {
+			    num = (unsigned int) num;
+			    negative = true;
+			  }
+		      }
+#else
+		    if ((int) num < 0)
+		      negative = true;
+#endif
+		  }
+
+		/* We use alloca() to allocate the buffer with the most
+		   pessimistic guess for the size.  Using alloca() allows
+		   having more than one integer formatting in a call.  */
+		char *buf = (char *) alloca (1 + 3 * sizeof (unsigned long int));
+		char *endp = &buf[1 + 3 * sizeof (unsigned long int)];
+		char *cp = _itoa (num, endp, *fmt == 'x' ? 16 : 10, 0);
+
+		/* Pad to the width the user specified.  */
+		if (width != -1)
+		  while (endp - cp < width)
+		    *--cp = fill;
+
+		if (negative)
+		  *--cp = '-';
+
+		iov[niov].iov_base = cp;
+		iov[niov].iov_len = endp - cp;
+		++niov;
+	      }
+	      break;
+
+	    case 's':
+	      /* Get the string argument.  */
+	      iov[niov].iov_base = va_arg (arg, char *);
+	      iov[niov].iov_len = strlen (iov[niov].iov_base);
+	      if (prec != -1)
+		iov[niov].iov_len = MIN ((size_t) prec, iov[niov].iov_len);
+	      ++niov;
+	      break;
+
+	    case '%':
+	      iov[niov].iov_base = (void *) fmt;
+	      iov[niov].iov_len = 1;
+	      ++niov;
+	      break;
+
+	    default:
+	      assert (! "invalid format specifier");
+	    }
+	  ++fmt;
+	}
+      else if (*fmt == '\n')
+	{
+	  /* See whether we have to print a single newline character.  */
+	  if (fmt == startp)
+	    {
+	      iov[niov].iov_base = (char *) startp;
+	      iov[niov++].iov_len = 1;
+	    }
+	  else
+	    /* No, just add it to the rest of the string.  */
+	    ++iov[niov - 1].iov_len;
+
+	  /* Next line, print a tag again.  */
+	  tag_p = 1;
+	  ++fmt;
+	}
+    }
+
+  /* Finally write the result.  */
+  _dl_writev (fd, iov, niov);
+}
+
+
+/* Write to debug file.  */
+void
+_dl_debug_printf (const char *fmt, ...)
+{
+  va_list arg;
+
+  va_start (arg, fmt);
+  _dl_debug_vdprintf (GLRO(dl_debug_fd), 1, fmt, arg);
+  va_end (arg);
+}
+
+
+/* Write to debug file but don't start with a tag.  */
+void
+_dl_debug_printf_c (const char *fmt, ...)
+{
+  va_list arg;
+
+  va_start (arg, fmt);
+  _dl_debug_vdprintf (GLRO(dl_debug_fd), -1, fmt, arg);
+  va_end (arg);
+}
+
+
+/* Write the given file descriptor.  */
+void
+_dl_dprintf (int fd, const char *fmt, ...)
+{
+  va_list arg;
+
+  va_start (arg, fmt);
+  _dl_debug_vdprintf (fd, 0, fmt, arg);
+  va_end (arg);
+}
+
+void
+_dl_printf (const char *fmt, ...)
+{
+  va_list arg;
+
+  va_start (arg, fmt);
+  _dl_debug_vdprintf (STDOUT_FILENO, 0, fmt, arg);
+  va_end (arg);
+}
+
+void
+_dl_error_printf (const char *fmt, ...)
+{
+  va_list arg;
+
+  va_start (arg, fmt);
+  _dl_debug_vdprintf (STDERR_FILENO, 0, fmt, arg);
+  va_end (arg);
+}
+
+void
+_dl_fatal_printf (const char *fmt, ...)
+{
+  va_list arg;
+
+  va_start (arg, fmt);
+  _dl_debug_vdprintf (STDERR_FILENO, 0, fmt, arg);
+  va_end (arg);
+  _exit (127);
+}
+rtld_hidden_def (_dl_fatal_printf)