[git commit] ash: [PARSER] Handle backslash newlines properly after dollar sign
Denys Vlasenko
vda.linux at googlemail.com
Thu Sep 29 15:17:04 UTC 2016
commit: https://git.busybox.net/busybox/commit/?id=73c3e074df4de03ba1bebce09c130c8950ea5fe4
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
Fixes var_unbackslash1.tests failure.
Upstream commit:
[PARSER] Handle backslash newlines properly after dollar sign
On Tue, Aug 26, 2014 at 12:34:42PM +0000, Eric Blake wrote:
> On 08/26/2014 06:15 AM, Oleg Bulatov wrote:
> > While playing with sh generators I found that dash and bash have different
> > interpretations for <slash><newline> sequence.
> >
> > $ dash -c 'EDIT=xxx; echo $EDIT\
> >> OR'
> > xxxOR
>
> Buggy.
> >
> > $ dash -c 'echo "$\
> > (pwd)"'
> > $(pwd)
> >
> > Is it undefined behaviour in POSIX?
>
> No, it's well-defined, and dash is buggy.
...
I agree. This patch should resolve this problem and similar ones
affecting blackslash newlines after we encounter a dollar sign.
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
shell/ash.c | 44 +++++++++++++++++++++++++++++---------------
1 file changed, 29 insertions(+), 15 deletions(-)
diff --git a/shell/ash.c b/shell/ash.c
index a63d40d..b71fc02 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9774,11 +9774,6 @@ popstring(void)
INT_ON;
}
-//FIXME: BASH_COMPAT with "...&" does TWO pungetc():
-//it peeks whether it is &>, and then pushes back both chars.
-//This function needs to save last *next_to_pgetc to buf[0]
-//to make two pungetc() reliable. Currently,
-// pgetc (out of buf: does preadfd), pgetc, pungetc, pungetc won't work...
static int
preadfd(void)
{
@@ -10037,6 +10032,25 @@ pungetc(void)
g_parsefile->unget++;
}
+/* This one eats backslash+newline */
+static int
+pgetc_eatbnl(void)
+{
+ int c;
+
+ while ((c = pgetc()) == '\\') {
+ if (pgetc() != '\n') {
+ pungetc();
+ break;
+ }
+
+ g_parsefile->linno++;
+ setprompt_if(doprompt, 2);
+ }
+
+ return c;
+}
+
/*
* To handle the "." command, a stack of input files is used. Pushfile
* adds a new entry to the stack and popfile restores the previous level.
@@ -11625,7 +11639,7 @@ parsesub: {
int typeloc;
int flags;
- c = pgetc();
+ c = pgetc_eatbnl();
if (c > 255 /* PEOA or PEOF */
|| (c != '(' && c != '{' && !is_name(c) && !is_special(c))
) {
@@ -11638,7 +11652,7 @@ parsesub: {
pungetc();
} else if (c == '(') {
/* $(command) or $((arith)) */
- if (pgetc() == '(') {
+ if (pgetc_eatbnl() == '(') {
#if ENABLE_SH_MATH_SUPPORT
PARSEARITH();
#else
@@ -11655,9 +11669,9 @@ parsesub: {
USTPUTC(VSNORMAL, out);
subtype = VSNORMAL;
if (c == '{') {
- c = pgetc();
+ c = pgetc_eatbnl();
if (c == '#') {
- c = pgetc();
+ c = pgetc_eatbnl();
if (c == '}')
c = '#'; /* ${#} - same as $# */
else
@@ -11670,18 +11684,18 @@ parsesub: {
/* $[{[#]]NAME[}] */
do {
STPUTC(c, out);
- c = pgetc();
+ c = pgetc_eatbnl();
} while (c <= 255 /* not PEOA or PEOF */ && is_in_name(c));
} else if (isdigit(c)) {
/* $[{[#]]NUM[}] */
do {
STPUTC(c, out);
- c = pgetc();
+ c = pgetc_eatbnl();
} while (isdigit(c));
} else if (is_special(c)) {
/* $[{[#]]<specialchar>[}] */
USTPUTC(c, out);
- c = pgetc();
+ c = pgetc_eatbnl();
} else {
badsub:
raise_error_syntax("bad substitution");
@@ -11699,7 +11713,7 @@ parsesub: {
/* c == first char after VAR */
switch (c) {
case ':':
- c = pgetc();
+ c = pgetc_eatbnl();
#if ENABLE_ASH_BASH_COMPAT
/* This check is only needed to not misinterpret
* ${VAR:-WORD}, ${VAR:+WORD}, ${VAR:=WORD}, ${VAR:?WORD}
@@ -11724,7 +11738,7 @@ parsesub: {
case '#': {
int cc = c;
subtype = (c == '#' ? VSTRIMLEFT : VSTRIMRIGHT);
- c = pgetc();
+ c = pgetc_eatbnl();
if (c != cc)
goto do_pungetc;
subtype++;
@@ -11736,7 +11750,7 @@ parsesub: {
//TODO: encode pattern and repl separately.
// Currently ${v/$var_with_slash/repl} is horribly broken
subtype = VSREPLACE;
- c = pgetc();
+ c = pgetc_eatbnl();
if (c != '/')
goto do_pungetc;
subtype++; /* VSREPLACEALL */
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