read-file.c

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Hash : d0450ae9
Author :
Date : 2024-01-17T21:53:15

Improve naming of local variables.

* gnulib-tool, posix-modules, build-aux/relocatable.sh.in,
build-aux/reloc-ldflags, build-aux/install-reloc, tests/init.sh,
m4/argz.m4: Rename save_IFS to saved_IFS.
* m4/*.m4: Rename save_LIBS to saved_LIBS.
* m4/00gnulib.m4, m4/gnulib-common.m4, m4/warn-on-use.m4, m4/wchar_h.m4:
Rename save_ac_compile to saved_ac_compile.
* m4/00gnulib.m4: Rename ac_save_ac_compile to ac_saved_ac_compile.
* m4/gnulib-common.m4: Rename save_ac_compile_for_check_decl to
saved_ac_compile_for_check_decl.
* m4/assert_h.m4, m4/manywarnings.m4, m4/stdalign.m4, m4/visibility.m4:
Rename gl_save_CFLAGS to gl_saved_CFLAGS.
* m4/dirfd.m4: Rename dirfd_save_CFLAGS to gl_saved_CFLAGS.
* m4/include_next.m4, m4/pread.m4, m4/pwrite.m4, m4/termcap.m4,
m4/terminfo.m4: Rename gl_save_CPPFLAGS to gl_saved_CPPFLAGS.
* m4/lib-link.m4: Rename ac_save_CPPFLAGS to acl_save_CPPFLAGS.
* m4/iconv.m4, m4/readline.m4: Rename am_save_CPPFLAGS to
gl_saved_CPPFLAGS.
* m4/gettext.m4: Rename gt_save_CPPFLAGS to gt_saved_CPPFLAGS.
* m4/ansi-c++.m4: Rename gl_save_CXX to gl_saved_CXX.
* m4/manywarnings-c++.m4: Rename gl_save_CXXFLAGS to gl_saved_CXXFLAGS.
* m4/lib-link.m4: Rename acl_save_ifs to acl_saved_IFS.
* m4/lib-prefix.m4: Rename acl_save_IFS to acl_saved_IFS.
* m4/progtest.m4: Rename ac_save_IFS to gt_saved_IFS.
* m4/lib-link.m4: Rename save_libdir to saved_libdir, acl_save_libdir to
acl_saved_libdir.
* m4/ld-version-script.m4: Rename save_LDFLAGS to saved_LDFLAGS.
* m4/acl.m4, m4/getgroups.m4: Rename ac_save_LIBS to gl_saved_LIBS.
* m4/lib-link.m4: Rename ac_save_LIBS to acl_saved_LIBS.
* m4/getdomainname.m4, m4/gethostname.m4, m4/getloadavg.m4,
m4/hostent.m4, m4/inet_ntop.m4, m4/inet_pton.m4,
m4/pthread_mutex_timedlock.m4, m4/pthread_sigmask.m4,
m4/pthread-spin.m4, m4/readutmp.m4, m4/selinux-selinux-h.m4,
m4/servent.m4, m4/socketlib.m4, m4/termcap.m4, m4/terminfo.m4,
m4/thread.m4: Rename gl_save_LIBS to gl_saved_LIBS.
* m4/getaddrinfo.m4, m4/iconv.m4, m4/readline.m4: Rename am_save_LIBS to
gl_saved_LIBS.
* m4/gettext.m4, m4/intlmacosx.m4: Rename gt_save_LIBS to gt_saved_LIBS.
* m4/libunistring.m4: Rename glus_save_LIBS to glus_saved_LIBS.
* m4/nanosleep.m4: Rename nanosleep_save_libs to gl_saved_LIBS.
* m4/lib-prefix.m4: Rename acl_save_prefix to acl_saved_prefix,
acl_save_exec_prefix to acl_saved_exec_prefix.
* m4/configmake.m4: Rename gl_save_<variable> to gl_saved_<variable>.
* m4/terminfo.m4: Likewise.
* m4/gettext.m4: Rename gt_save_<variable> to gt_saved_<variable>.
* m4/javaexec.m4: Rename save_CLASSPATH to gt_saved_CLASSPATH.
* m4/warnings.m4: Rename gl_save_compiler_FLAGS to
gl_saved_compiler_FLAGS.
* lib/pread.c, lib/pwrite.c, lib/read-file.c, lib/tempname.c: Rename
save_errno to saved_errno.
* lib/read-file.c: Rename save_alloc to saved_alloc.
* lib/strptime.c: Rename save_wday to saved_wday, save_mday to
saved_mday, save_mon to saved_mon.

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lib/read-file.c

/* read-file.c -- read file contents into a string
   Copyright (C) 2006, 2009-2024 Free Software Foundation, Inc.
   Written by Simon Josefsson and Bruno Haible.

   This file 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.

   This file 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 this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

#include "read-file.h"

/* Get fstat.  */
#include <sys/stat.h>

/* Get ftello.  */
#include <stdio.h>

/* Get PTRDIFF_MAX.  */
#include <stdint.h>

/* Get malloc, realloc, free. */
#include <stdlib.h>

/* Get memcpy, memset_explicit. */
#include <string.h>

/* Get errno. */
#include <errno.h>

/* Read a STREAM and return a newly allocated string with the content,
   and set *LENGTH to the length of the string.  The string is
   zero-terminated, but the terminating zero byte is not counted in
   *LENGTH.  On errors, *LENGTH is undefined, errno preserves the
   values set by system functions (if any), and NULL is returned.

   If the RF_SENSITIVE flag is set in FLAGS:
     - You should control the buffering of STREAM using 'setvbuf'.  Either
       clear the buffer of STREAM after closing it, or disable buffering of
       STREAM before calling this function.
     - The memory buffer internally allocated will be cleared upon failure.  */
char *
fread_file (FILE *stream, int flags, size_t *length)
{
  char *buf = NULL;
  size_t alloc = BUFSIZ;

  /* For a regular file, allocate a buffer that has exactly the right
     size.  This avoids the need to do dynamic reallocations later.  */
  {
    struct stat st;

    if (fstat (fileno (stream), &st) >= 0 && S_ISREG (st.st_mode))
      {
        off_t pos = ftello (stream);

        if (pos >= 0 && pos < st.st_size)
          {
            off_t alloc_off = st.st_size - pos;

            /* '1' below, accounts for the trailing NUL.  */
            if (PTRDIFF_MAX - 1 < alloc_off)
              {
                errno = ENOMEM;
                return NULL;
              }

            alloc = alloc_off + 1;
          }
      }
  }

  if (!(buf = malloc (alloc)))
    return NULL; /* errno is ENOMEM.  */

  {
    size_t size = 0; /* number of bytes read so far */
    int saved_errno;

    for (;;)
      {
        /* This reads 1 more than the size of a regular file
           so that we get eof immediately.  */
        size_t requested = alloc - size;
        size_t count = fread (buf + size, 1, requested, stream);
        size += count;

        if (count != requested)
          {
            saved_errno = errno;
            if (ferror (stream))
              break;

            /* Shrink the allocated memory if possible.  */
            if (size < alloc - 1)
              {
                if (flags & RF_SENSITIVE)
                  {
                    char *smaller_buf = malloc (size + 1);
                    if (smaller_buf == NULL)
                      memset_explicit (buf + size, 0, alloc - size);
                    else
                      {
                        memcpy (smaller_buf, buf, size);
                        memset_explicit (buf, 0, alloc);
                        free (buf);
                        buf = smaller_buf;
                      }
                  }
                else
                  {
                    char *smaller_buf = realloc (buf, size + 1);
                    if (smaller_buf != NULL)
                      buf = smaller_buf;
                  }
              }

            buf[size] = '\0';
            *length = size;
            return buf;
          }

        {
          char *new_buf;
          size_t saved_alloc = alloc;

          if (alloc == PTRDIFF_MAX)
            {
              saved_errno = ENOMEM;
              break;
            }

          if (alloc < PTRDIFF_MAX - alloc / 2)
            alloc = alloc + alloc / 2;
          else
            alloc = PTRDIFF_MAX;

          if (flags & RF_SENSITIVE)
            {
              new_buf = malloc (alloc);
              if (!new_buf)
                {
                  /* BUF should be cleared below after the loop.  */
                  saved_errno = errno;
                  break;
                }
              memcpy (new_buf, buf, saved_alloc);
              memset_explicit (buf, 0, saved_alloc);
              free (buf);
            }
          else if (!(new_buf = realloc (buf, alloc)))
            {
              saved_errno = errno;
              break;
            }

          buf = new_buf;
        }
      }

    if (flags & RF_SENSITIVE)
      memset_explicit (buf, 0, alloc);

    free (buf);
    errno = saved_errno;
    return NULL;
  }
}

/* Open and read the contents of FILENAME, and return a newly
   allocated string with the content, and set *LENGTH to the length of
   the string.  The string is zero-terminated, but the terminating
   zero byte is not counted in *LENGTH.  On errors, *LENGTH is
   undefined, errno preserves the values set by system functions (if
   any), and NULL is returned.

   If the RF_BINARY flag is set in FLAGS, the file is opened in binary
   mode.  If the RF_SENSITIVE flag is set in FLAGS, the memory buffer
   internally allocated will be cleared upon failure.  */
char *
read_file (const char *filename, int flags, size_t *length)
{
  const char *mode = (flags & RF_BINARY) ? "rbe" : "re";
  FILE *stream = fopen (filename, mode);
  char *out;

  if (!stream)
    return NULL;

  if (flags & RF_SENSITIVE)
    setvbuf (stream, NULL, _IONBF, 0);

  out = fread_file (stream, flags, length);

  if (fclose (stream) != 0)
    {
      if (out)
        {
          if (flags & RF_SENSITIVE)
            memset_explicit (out, 0, *length);
          free (out);
        }
      return NULL;
    }

  return out;
}

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kc3-lang/gnulib/lib/read-file.c

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lib/read-file.c