/usr/src/gnu/usr.bin/texinfo/info/tilde.c

Bug Summary

File:	src/gnu/usr.bin/texinfo/info/tilde.c
Warning:	line 139, column 7 Null pointer passed as 1st argument to string copy function

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name tilde.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/texinfo/obj/info -resource-dir /usr/local/lib/clang/13.0.0 -D HAVE_CONFIG_H -D LOCALEDIR="/usr/share/locale" -D INFODIR="/usr/share/info" -D INFODIR2="/usr/share/info" -I . -I /usr/src/gnu/usr.bin/texinfo/info -I .. -I . -I /usr/src/gnu/usr.bin/texinfo/lib -I ../intl -I .. -I /usr/src/gnu/usr.bin/texinfo/info -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/gnu/usr.bin/texinfo/obj/info -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/gnu/usr.bin/texinfo/info/tilde.c

1/* tilde.c -- tilde expansion code (~/foo := $HOME/foo).
 $Id: tilde.c,v 1.4 2006/07/17 16:12:36 espie Exp $

 Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1996, 1998, 1999,
 2002, 2004 Free Software Foundation, Inc.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2, or (at your option)
 any later version.

 This program 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 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 Written by Brian Fox (bfox@ai.mit.edu). */

23/* Include config.h before doing alloca.  */
24#include "info.h"
25#include "tilde.h"

27#if defined (TEST) || defined (STATIC_MALLOC)
28static void *xmalloc (), *xrealloc ();
29#endif /* TEST || STATIC_MALLOC */

31/* The default value of tilde_additional_prefixes.  This is set to
 whitespace preceding a tilde so that simple programs which do not
 perform any word separation get desired behaviour. */
34static char *default_prefixes[] =
{ " ~", "\t~", (char *)NULL((void *)0) };

37/* The default value of tilde_additional_suffixes.  This is set to
 whitespace or newline so that simple programs which do not
 perform any word separation get desired behaviour. */
40static char *default_suffixes[] =
{ " ", "\n", (char *)NULL((void *)0) };

43/* If non-null, this contains the address of a function to call if the
 standard meaning for expanding a tilde fails.  The function is called
 with the text (sans tilde, as in "foo"), and returns a malloc()'ed string
 which is the expansion, or a NULL pointer if there is no expansion. */
47CFunction *tilde_expansion_failure_hook = (CFunction *)NULL((void *)0);

49/* When non-null, this is a NULL terminated array of strings which
 are duplicates for a tilde prefix.  Bash uses this to expand
 `=~' and `:~'. */
52char **tilde_additional_prefixes = default_prefixes;

54/* When non-null, this is a NULL terminated array of strings which match
 the end of a username, instead of just "/".  Bash sets this to
 `:' and `=~'. */
57char **tilde_additional_suffixes = default_suffixes;

59/* Find the start of a tilde expansion in STRING, and return the index of
 the tilde which starts the expansion.  Place the length of the text
 which identified this tilde starter in LEN, excluding the tilde itself. */
62static int
63tilde_find_prefix (char *string, int *len)
64{
register int i, j, string_len;
register char **prefixes = tilde_additional_prefixes;

string_len = strlen (string);
*len = 0;

if (!*string || *string == '~')
  return (0);

if (prefixes)
  {
    for (i = 0; i < string_len; i++)
      {
        for (j = 0; prefixes[j]; j++)
          {
            if (strncmp (string + i, prefixes[j], strlen (prefixes[j])) == 0)
              {
                *len = strlen (prefixes[j]) - 1;
                return (i + *len);
              }
          }
      }
  }
return (string_len);
89}

91/* Find the end of a tilde expansion in STRING, and return the index of
 the character which ends the tilde definition.  */
93static int
94tilde_find_suffix (char *string)
95{
register int i, j, string_len;
register char **suffixes = tilde_additional_suffixes;

string_len = strlen (string);

for (i = 0; i < string_len; i++)
  {
    if (IS_SLASH (string[i])((string[i]) == '/') || !string[i])
      break;

    for (j = 0; suffixes && suffixes[j]; j++)
      {
        if (strncmp (string + i, suffixes[j], strlen (suffixes[j])) == 0)
          return (i);
      }
  }
return (i);
113}

115/* Return a new string which is the result of tilde expanding STRING. */
116char *
117tilde_expand (char *string)
118{
char *result;
int result_size, result_index;

result_size = result_index = 0;
result = (char *)NULL((void *)0);
1
Null pointer value stored to 'result'→

/* Scan through STRING expanding tildes as we come to them. */
while (1)
2
←
Loop condition is true.  Entering loop body→
  {
    register int start, end;
    char *tilde_word, *expansion;
    int len;

    /* Make START point to the tilde which starts the expansion. */
    start = tilde_find_prefix (string, &len);

    /* Copy the skipped text into the result. */
    if ((result_index + start + 1) > result_size)
3
←
Assuming the condition is false→
4
←
Taking false branch→
      result = (char *)xrealloc (result, 1 + (result_size += (start + 20)));

    strncpy (result + result_index, string, start);
5
←
Null pointer passed as 1st argument to string copy function
    result_index += start;

    /* Advance STRING to the starting tilde. */
    string += start;

    /* Make END be the index of one after the last character of the
       username. */
    end = tilde_find_suffix (string);

    /* If both START and END are zero, we are all done. */
    if (!start && !end)
      break;

    /* Expand the entire tilde word, and copy it into RESULT. */
    tilde_word = (char *)xmalloc (1 + end);
    strncpy (tilde_word, string, end);
    tilde_word[end] = '\0';
    string += end;

    expansion = tilde_expand_word (tilde_word);
    free (tilde_word);

    len = strlen (expansion);
    if ((result_index + len + 1) > result_size)
      result = (char *)xrealloc (result, 1 + (result_size += (len + 20)));

    strcpy (result + result_index, expansion);
    result_index += len;
    free (expansion);
  }

result[result_index] = '\0';

return (result);
174}

176/* Do the work of tilde expansion on FILENAME.  FILENAME starts with a
 tilde.  If there is no expansion, call tilde_expansion_failure_hook. */
178char *
179tilde_expand_word (char *filename)
180{
char *dirname = filename ? xstrdup (filename) : NULL((void *)0);

if (dirname && *dirname == '~')
  {
    char *temp_name;
    if (!dirname[1] || IS_SLASH (dirname[1])((dirname[1]) == '/'))
      {
        /* Prepend $HOME to the rest of the string. */
        char *temp_home = getenv ("HOME");

        /* If there is no HOME variable, look up the directory in
           the password database. */
        if (!temp_home)
          {
            struct passwd *entry;

            entry = (struct passwd *) getpwuid (getuid ());
            if (entry)
              temp_home = entry->pw_dir;
          }

        temp_name = xmalloc (1 + strlen (&dirname[1])
                             + (temp_home ? strlen (temp_home) : 0));
        if (temp_home)
          strcpy (temp_name, temp_home);
        else
          temp_name[0] = 0;
        strcat (temp_name, &dirname[1]);
        free (dirname);
        dirname = xstrdup (temp_name);
        free (temp_name);
      }
    else
      {
        struct passwd *user_entry;
        char *username = xmalloc (257);
        int i, c;

        for (i = 1; (c = dirname[i]); i++)
          {
            if (IS_SLASH (c)((c) == '/'))
              break;
            else
              username[i - 1] = c;
          }
        username[i - 1] = 0;

        if (!(user_entry = (struct passwd *) getpwnam (username)))
          {
            /* If the calling program has a special syntax for
               expanding tildes, and we couldn't find a standard
               expansion, then let them try. */
            if (tilde_expansion_failure_hook)
              {
                char *expansion = (*tilde_expansion_failure_hook) (username);

                if (expansion)
                  {
                    temp_name = xmalloc (1 + strlen (expansion)
                                         + strlen (&dirname[i])); 
                    strcpy (temp_name, expansion);
                    strcat (temp_name, &dirname[i]);
                    free (expansion);
                    goto return_name;
                  }
              }
            /* We shouldn't report errors. */
          }
        else
          {
            temp_name = xmalloc (1 + strlen (user_entry->pw_dir)
                                 + strlen (&dirname[i])); 
            strcpy (temp_name, user_entry->pw_dir);
            strcat (temp_name, &dirname[i]);

          return_name:
            free (dirname);
            dirname = xstrdup (temp_name);
            free (temp_name);
          }

        endpwent ();
        free (username);
      }
  }
return dirname;
267}

269
270#if defined (TEST)
271#undef NULL((void *)0)
272#include <stdio.h>

274main (argc, argv)
   int argc;
   char **argv;
277{
char *result, line[512];
int done = 0;

while (!done)
  {
    printf ("~expand: ");
    fflush (stdout(&__sF[1]));

    if (!gets (line))
      strcpy (line, "done");

    if ((strcmp (line, "done") == 0) ||
        (strcmp (line, "quit") == 0) ||
        (strcmp (line, "exit") == 0))
      {
        done = 1;
        break;
      }

    result = tilde_expand (line);
    printf ("  --> %s\n", result);
    free (result);
  }
xexit (0);
302}

304static void memory_error_and_abort ();

306static void *
307xmalloc (bytes)
   int bytes;
309{
void *temp = (void *)malloc (bytes);

if (!temp)
  memory_error_and_abort ();
return (temp);
315}

317static void *
318xrealloc (pointer, bytes)
   void *pointer;
   int bytes;
321{
void *temp;

if (!pointer)
  temp = (char *)malloc (bytes);
else
  temp = (char *)realloc (pointer, bytes);

if (!temp)
  memory_error_and_abort ();

return (temp);
333}

335static void
336memory_error_and_abort ()
337{
fprintf (stderr(&__sF[2]), _("readline: Out of virtual memory!\n")((const char *) ("readline: Out of virtual memory!\n")));
abort ();
340}
341#endif /* TEST */
