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/* Shell format strings.
Copyright (C) 2003-2004, 2006-2007, 2009, 2019-2020 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2003.
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 3 of the License, 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, see <https://www.gnu.org/licenses/>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "format.h"
#include "c-ctype.h"
#include "xalloc.h"
#include "format-invalid.h"
#include "gettext.h"
#define _(str) gettext (str)
/* Shell format strings are simply strings subjects to variable substitution.
A variable substitution starts with '$' and is finished by either
- a nonempty sequence of alphanumeric ASCII characters, the first being
not a digit, or
- an opening brace '{', a nonempty sequence of alphanumeric ASCII
characters, the first being not a digit, and a closing brace '}'.
We don't support variable references like $1, $$ or $? since they make
no sense when 'envsubst' is invoked.
We don't support non-ASCII variable names, to avoid dependencies w.r.t. the
current encoding: While "${\xe0}" looks like a variable access in ISO-8859-1
encoding, it doesn't look like one in the BIG5, BIG5-HKSCS, GBK, GB18030,
SHIFT_JIS, JOHAB encodings, because \xe0\x7d is a single character in these
encodings.
We don't support the POSIX syntax for default or alternate values:
${variable-default} ${variable:-default}
${variable=default} ${variable:=default}
${variable+replacement} ${variable:+replacement}
${variable?ignored} ${variable:?ignored}
because the translator might be tempted to change the default value; if
we allow it we have a security problem; if we don't allow it the translator
will be surprised.
*/
struct named_arg
{
char *name;
};
struct spec
{
unsigned int directives;
unsigned int named_arg_count;
struct named_arg *named;
};
static int
named_arg_compare (const void *p1, const void *p2)
{
return strcmp (((const struct named_arg *) p1)->name,
((const struct named_arg *) p2)->name);
}
#define INVALID_NON_ASCII_VARIABLE() \
xstrdup (_("The string refers to a shell variable with a non-ASCII name."))
#define INVALID_SHELL_SYNTAX() \
xstrdup (_("The string refers to a shell variable with complex shell brace syntax. This syntax is unsupported here due to security reasons."))
#define INVALID_CONTEXT_DEPENDENT_VARIABLE() \
xstrdup (_("The string refers to a shell variable whose value may be different inside shell functions."))
#define INVALID_EMPTY_VARIABLE() \
xstrdup (_("The string refers to a shell variable with an empty name."))
static void *
format_parse (const char *format, bool translated, char *fdi,
char **invalid_reason)
{
const char *const format_start = format;
struct spec spec;
unsigned int named_allocated;
struct spec *result;
spec.directives = 0;
spec.named_arg_count = 0;
spec.named = NULL;
named_allocated = 0;
for (; *format != '\0';)
if (*format++ == '$')
{
/* A variable substitution. */
char *name;
FDI_SET (format - 1, FMTDIR_START);
spec.directives++;
if (*format == '{')
{
const char *name_start;
const char *name_end;
size_t n;
name_start = ++format;
for (; *format != '\0'; format++)
{
if (*format == '}')
break;
if (!c_isascii (*format))
{
*invalid_reason = INVALID_NON_ASCII_VARIABLE ();
FDI_SET (format, FMTDIR_ERROR);
goto bad_format;
}
if (format > name_start
&& (*format == '-' || *format == '=' || *format == '+'
|| *format == '?' || *format == ':'))
{
*invalid_reason = INVALID_SHELL_SYNTAX ();
FDI_SET (format, FMTDIR_ERROR);
goto bad_format;
}
if (!(c_isalnum (*format) || *format == '_')
|| (format == name_start && c_isdigit (*format)))
{
*invalid_reason = INVALID_CONTEXT_DEPENDENT_VARIABLE ();
FDI_SET (format, FMTDIR_ERROR);
goto bad_format;
}
}
if (*format == '\0')
{
*invalid_reason = INVALID_UNTERMINATED_DIRECTIVE ();
FDI_SET (format - 1, FMTDIR_ERROR);
goto bad_format;
}
name_end = format++;
n = name_end - name_start;
if (n == 0)
{
*invalid_reason = INVALID_EMPTY_VARIABLE ();
FDI_SET (format - 1, FMTDIR_ERROR);
goto bad_format;
}
name = XNMALLOC (n + 1, char);
memcpy (name, name_start, n);
name[n] = '\0';
}
else if (c_isalpha (*format) || *format == '_')
{
const char *name_start;
const char *name_end;
size_t n;
name_start = format;
do
format++;
while (*format != '\0' && (c_isalnum (*format) || *format == '_'));
name_end = format;
n = name_end - name_start;
name = XNMALLOC (n + 1, char);
memcpy (name, name_start, n);
name[n] = '\0';
}
else if (*format != '\0')
{
if (!c_isascii (*format))
{
*invalid_reason = INVALID_NON_ASCII_VARIABLE ();
FDI_SET (format, FMTDIR_ERROR);
goto bad_format;
}
else
{
*invalid_reason = INVALID_CONTEXT_DEPENDENT_VARIABLE ();
FDI_SET (format, FMTDIR_ERROR);
goto bad_format;
}
}
else
{
*invalid_reason = INVALID_UNTERMINATED_DIRECTIVE ();
FDI_SET (format - 1, FMTDIR_ERROR);
goto bad_format;
}
/* Named argument. */
if (named_allocated == spec.named_arg_count)
{
named_allocated = 2 * named_allocated + 1;
spec.named = (struct named_arg *) xrealloc (spec.named, named_allocated * sizeof (struct named_arg));
}
spec.named[spec.named_arg_count].name = name;
spec.named_arg_count++;
FDI_SET (format - 1, FMTDIR_END);
}
/* Sort the named argument array, and eliminate duplicates. */
if (spec.named_arg_count > 1)
{
unsigned int i, j;
qsort (spec.named, spec.named_arg_count, sizeof (struct named_arg),
named_arg_compare);
/* Remove duplicates: Copy from i to j, keeping 0 <= j <= i. */
for (i = j = 0; i < spec.named_arg_count; i++)
if (j > 0 && strcmp (spec.named[i].name, spec.named[j-1].name) == 0)
free (spec.named[i].name);
else
{
if (j < i)
spec.named[j].name = spec.named[i].name;
j++;
}
spec.named_arg_count = j;
}
result = XMALLOC (struct spec);
*result = spec;
return result;
bad_format:
if (spec.named != NULL)
{
unsigned int i;
for (i = 0; i < spec.named_arg_count; i++)
free (spec.named[i].name);
free (spec.named);
}
return NULL;
}
static void
format_free (void *descr)
{
struct spec *spec = (struct spec *) descr;
if (spec->named != NULL)
{
unsigned int i;
for (i = 0; i < spec->named_arg_count; i++)
free (spec->named[i].name);
free (spec->named);
}
free (spec);
}
static int
format_get_number_of_directives (void *descr)
{
struct spec *spec = (struct spec *) descr;
return spec->directives;
}
static bool
format_check (void *msgid_descr, void *msgstr_descr, bool equality,
formatstring_error_logger_t error_logger,
const char *pretty_msgid, const char *pretty_msgstr)
{
struct spec *spec1 = (struct spec *) msgid_descr;
struct spec *spec2 = (struct spec *) msgstr_descr;
bool err = false;
if (spec1->named_arg_count + spec2->named_arg_count > 0)
{
unsigned int i, j;
unsigned int n1 = spec1->named_arg_count;
unsigned int n2 = spec2->named_arg_count;
/* Check the argument names are the same.
Both arrays are sorted. We search for the first difference. */
for (i = 0, j = 0; i < n1 || j < n2; )
{
int cmp = (i >= n1 ? 1 :
j >= n2 ? -1 :
strcmp (spec1->named[i].name, spec2->named[j].name));
if (cmp > 0)
{
if (error_logger)
error_logger (_("a format specification for argument '%s', as in '%s', doesn't exist in '%s'"),
spec2->named[j].name, pretty_msgstr,
pretty_msgid);
err = true;
break;
}
else if (cmp < 0)
{
if (equality)
{
if (error_logger)
error_logger (_("a format specification for argument '%s' doesn't exist in '%s'"),
spec1->named[i].name, pretty_msgstr);
err = true;
break;
}
else
i++;
}
else
j++, i++;
}
}
return err;
}
struct formatstring_parser formatstring_sh =
{
format_parse,
format_free,
format_get_number_of_directives,
NULL,
format_check
};
#ifdef TEST
/* Test program: Print the argument list specification returned by
format_parse for strings read from standard input. */
#include <stdio.h>
static void
format_print (void *descr)
{
struct spec *spec = (struct spec *) descr;
unsigned int i;
if (spec == NULL)
{
printf ("INVALID");
return;
}
printf ("{");
for (i = 0; i < spec->named_arg_count; i++)
{
if (i > 0)
printf (", ");
printf ("'%s'", spec->named[i].name);
}
printf ("}");
}
int
main ()
{
for (;;)
{
char *line = NULL;
size_t line_size = 0;
int line_len;
char *invalid_reason;
void *descr;
line_len = getline (&line, &line_size, stdin);
if (line_len < 0)
break;
if (line_len > 0 && line[line_len - 1] == '\n')
line[--line_len] = '\0';
invalid_reason = NULL;
descr = format_parse (line, false, NULL, &invalid_reason);
format_print (descr);
printf ("\n");
if (descr == NULL)
printf ("%s\n", invalid_reason);
free (invalid_reason);
free (line);
}
return 0;
}
/*
* For Emacs M-x compile
* Local Variables:
* compile-command: "/bin/sh ../libtool --tag=CC --mode=link gcc -o a.out -static -O -g -Wall -I.. -I../gnulib-lib -I../../gettext-runtime/intl -DHAVE_CONFIG_H -DTEST format-sh.c ../gnulib-lib/libgettextlib.la"
* End:
*/
#endif /* TEST */