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ash: fix handling of ${VAR: -2}

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2016-07-25 03:56:00 +02:00
parent 0fb0045aa9
commit f8ddbe1ccc
3 changed files with 25 additions and 4 deletions
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12
shell/ash.c
View File

@ -6323,6 +6323,8 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
#if ENABLE_ASH_BASH_COMPAT
case VSSUBSTR:
//TODO: support more general format ${v:EXPR:EXPR},
// where EXPR follows $(()) rules
loc = str = stackblock() + strloc;
/* Read POS in ${var:POS:LEN} */
pos = atoi(loc); /* number(loc) errors out on "1:4" */
@ -11577,15 +11579,18 @@ parsesub: {
STPUTC('=', out);
flags = 0;
if (subtype == 0) {
static const char types[] ALIGN1 = "}-+?=";
/* ${VAR...} but not $VAR or ${#VAR} */
/* c == first char after VAR */
switch (c) {
case ':':
c = pgetc();
#if ENABLE_ASH_BASH_COMPAT
if (c == ':' || c == '$' || isdigit(c)) {
//TODO: support more general format ${v:EXPR:EXPR},
// where EXPR follows $(()) rules
/* This check is only needed to not misinterpret
* ${VAR:-WORD}, ${VAR:+WORD}, ${VAR:=WORD}, ${VAR:?WORD}
* constructs.
*/
if (!strchr(types, c)) {
subtype = VSSUBSTR;
pungetc();
break; /* "goto do_pungetc" is bigger (!) */
@ -11594,7 +11599,6 @@ parsesub: {
flags = VSNUL;
/*FALLTHROUGH*/
default: {
static const char types[] ALIGN1 = "}-+?=";
const char *p = strchr(types, c);
if (p == NULL)
goto badsub;

6
shell/ash_test/ash-vars/var_bash1a.right Normal file
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@ -0,0 +1,6 @@
parameter 'abcdef'
varoffset2 'cdef'
varoffset-2 'ef'
literal '2' 'cdef'
literal '-2' 'abcdef'
literal ' -2' 'ef'

11
shell/ash_test/ash-vars/var_bash1a.tests Executable file
View File

@ -0,0 +1,11 @@
parameter=abcdef
offset=2
noffset=-2
echo "parameter '${parameter}'"
echo "varoffset2 '${parameter:${offset}}'"
echo "varoffset-2 '${parameter:${noffset}}'"
echo "literal '2' '${parameter:2}'"
# This is not inrpreted as ${VAR:POS{:LEN}},
# but as ${VAR:=WORD} - if VAR is unset or null, substitute WORD
echo "literal '-2' '${parameter:-2}'"
echo "literal ' -2' '${parameter: -2}'"