Adding upstream version 9.4.upstream/9.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 216 insertions, 0 deletions

diff --git a/lib/read-file.c b/lib/read-file.c
new file mode 100644
index 0000000..1e62085
--- /dev/null
+++ b/lib/read-file.c
@@ -0,0 +1,216 @@
+/* read-file.c -- read file contents into a string
+   Copyright (C) 2006, 2009-2023 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 save_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)
+          {
+            save_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 save_alloc = alloc;
+
+          if (alloc == PTRDIFF_MAX)
+            {
+              save_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.  */
+                  save_errno = errno;
+                  break;
+                }
+              memcpy (new_buf, buf, save_alloc);
+              memset_explicit (buf, 0, save_alloc);
+              free (buf);
+            }
+          else if (!(new_buf = realloc (buf, alloc)))
+            {
+              save_errno = errno;
+              break;
+            }
+
+          buf = new_buf;
+        }
+      }
+
+    if (flags & RF_SENSITIVE)
+      memset_explicit (buf, 0, alloc);
+
+    free (buf);
+    errno = save_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;
+}