Re: [PATCH v2 2/6] elf: Split dl-printf.c from dl-misc.c

["H.J. Lu" <hjl.tools@gmail.com>]

On Fri, Jan 14, 2022 at 8:53 AM Florian Weimer via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> This allows to use different compiler flags for the diagnostics
> code.
> ---
> v2: Adjust to Makefile changes in patch 1.
>  elf/Makefile    |   1 +
>  elf/dl-misc.c   | 281 +---------------------------------------------
>  elf/dl-printf.c | 292 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 297 insertions(+), 277 deletions(-)
>  create mode 100644 elf/dl-printf.c
>
> diff --git a/elf/Makefile b/elf/Makefile
> index 3065efc485..3df49742ff 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -69,6 +69,7 @@ dl-routines = \
>    dl-object \
>    dl-open \
>    dl-origin \
> +  dl-printf \
>    dl-profile \
>    dl-reloc \
>    dl-runtime \
> diff --git a/elf/dl-misc.c b/elf/dl-misc.c
> index 452b79de4a..6f40c28820 100644
> --- a/elf/dl-misc.c
> +++ b/elf/dl-misc.c
> @@ -16,24 +16,16 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -#include <assert.h>
> +#include <_itoa.h>
>  #include <fcntl.h>
>  #include <ldsodefs.h>
> -#include <limits.h>
>  #include <link.h>
> -#include <stdarg.h>
> -#include <stdlib.h>
> -#include <string.h>
> -#include <unistd.h>
> +#include <not-cancel.h>
>  #include <stdint.h>
> +#include <stdlib.h>
>  #include <sys/mman.h>
> -#include <sys/param.h>
>  #include <sys/stat.h>
> -#include <sys/uio.h>
> -#include <sysdep.h>
> -#include <_itoa.h>
> -#include <dl-writev.h>
> -#include <not-cancel.h>
> +#include <unistd.h>
>
>  /* Read the whole contents of FILE into new mmap'd space with given
>     protections.  *SIZEP gets the size of the file.  On error MAP_FAILED
> @@ -70,270 +62,6 @@ _dl_sysdep_read_whole_file (const char *file, size_t *sizep, int prot)
>    return result;
>  }
>
> -
> -/* 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)
> -
>  /* Test whether given NAME matches any of the names of the given object.  */
>  int
>  _dl_name_match_p (const char *name, const struct link_map *map)
> @@ -354,7 +82,6 @@ _dl_name_match_p (const char *name, const struct link_map *map)
>    return 0;
>  }
>
> -
>  unsigned long int
>  _dl_higher_prime_number (unsigned long int n)
>  {
> 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)
> --
> 2.34.1
>
>

LGTM.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Thanks.


-- 
H.J.