ash: input: Allow two consecutive calls to pungetc
Upstream commit:
input: Allow two consecutive calls to pungetc
The commit ef91d3d6a4c39421fd3a391e02cd82f9f3aee4a8 ([PARSER]
Handle backslash newlines properly after dollar sign) created
cases where we make two consecutive calls to pungetc. As we
don't explicitly support that there are corner cases where you
end up with garbage input leading to undefined behaviour.
This patch adds explicit support for two consecutive calls to
pungetc.
Reported-by: Jilles Tjoelker <jilles@stack.nl>
Reported-by: Juergen Daubert <jue@jue.li>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In bbox case, bashism >& may need two pungetc() too.
function old new delta
pgetc 514 555 +41
pushstring 114 144 +30
basepf 52 76 +24
popstring 134 151 +17
parse_command 1584 1585 +1
pungetc 12 9 -3
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/1 up/down: 113/-3) Total: 110 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
78c9c736ab
commit
3b4d04b77e
77
shell/ash.c
77
shell/ash.c
@ -1168,6 +1168,12 @@ struct strpush {
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struct alias *ap; /* if push was associated with an alias */
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#endif
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char *string; /* remember the string since it may change */
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/* Remember last two characters for pungetc. */
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int lastc[2];
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/* Number of outstanding calls to pungetc. */
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int unget;
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};
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struct parsefile {
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@ -1180,6 +1186,12 @@ struct parsefile {
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char *buf; /* input buffer */
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struct strpush *strpush; /* for pushing strings at this level */
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struct strpush basestrpush; /* so pushing one is fast */
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/* Remember last two characters for pungetc. */
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int lastc[2];
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/* Number of outstanding calls to pungetc. */
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int unget;
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};
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static struct parsefile basepf; /* top level input file */
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@ -9715,6 +9727,8 @@ pushstring(char *s, struct alias *ap)
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g_parsefile->strpush = sp;
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sp->prev_string = g_parsefile->next_to_pgetc;
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sp->prev_left_in_line = g_parsefile->left_in_line;
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sp->unget = g_parsefile->unget;
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memcpy(sp->lastc, g_parsefile->lastc, sizeof(sp->lastc));
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#if ENABLE_ASH_ALIAS
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sp->ap = ap;
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if (ap) {
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@ -9724,6 +9738,7 @@ pushstring(char *s, struct alias *ap)
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#endif
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g_parsefile->next_to_pgetc = s;
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g_parsefile->left_in_line = len;
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g_parsefile->unget = 0;
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INT_ON;
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}
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@ -9751,6 +9766,8 @@ popstring(void)
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#endif
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g_parsefile->next_to_pgetc = sp->prev_string;
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g_parsefile->left_in_line = sp->prev_left_in_line;
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g_parsefile->unget = sp->unget;
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memcpy(g_parsefile->lastc, sp->lastc, sizeof(sp->lastc));
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g_parsefile->strpush = sp->prev;
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if (sp != &(g_parsefile->basestrpush))
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free(sp);
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@ -9846,13 +9863,14 @@ preadfd(void)
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*/
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//#define pgetc_debug(...) bb_error_msg(__VA_ARGS__)
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#define pgetc_debug(...) ((void)0)
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static int pgetc(void);
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static int
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preadbuffer(void)
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{
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char *q;
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int more;
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while (g_parsefile->strpush) {
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if (g_parsefile->strpush) {
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#if ENABLE_ASH_ALIAS
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if (g_parsefile->left_in_line == -1
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&& g_parsefile->strpush->ap
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@ -9864,13 +9882,7 @@ preadbuffer(void)
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}
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#endif
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popstring();
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/* try "pgetc" now: */
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pgetc_debug("preadbuffer internal pgetc at %d:%p'%s'",
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g_parsefile->left_in_line,
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g_parsefile->next_to_pgetc,
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g_parsefile->next_to_pgetc);
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if (--g_parsefile->left_in_line >= 0)
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return (unsigned char)(*g_parsefile->next_to_pgetc++);
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return pgetc();
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}
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/* on both branches above g_parsefile->left_in_line < 0.
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* "pgetc" needs refilling.
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@ -9949,27 +9961,28 @@ preadbuffer(void)
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return (unsigned char)*g_parsefile->next_to_pgetc++;
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}
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#define pgetc_as_macro() \
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(--g_parsefile->left_in_line >= 0 \
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? (unsigned char)*g_parsefile->next_to_pgetc++ \
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: preadbuffer() \
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)
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static int
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pgetc(void)
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{
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pgetc_debug("pgetc_fast at %d:%p'%s'",
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int c;
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pgetc_debug("pgetc at %d:%p'%s'",
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g_parsefile->left_in_line,
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g_parsefile->next_to_pgetc,
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g_parsefile->next_to_pgetc);
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return pgetc_as_macro();
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}
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if (g_parsefile->unget)
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return g_parsefile->lastc[--g_parsefile->unget];
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#if ENABLE_ASH_OPTIMIZE_FOR_SIZE
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# define pgetc_fast() pgetc()
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#else
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# define pgetc_fast() pgetc_as_macro()
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#endif
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if (--g_parsefile->left_in_line >= 0)
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c = (signed char)*g_parsefile->next_to_pgetc++;
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else
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c = preadbuffer();
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g_parsefile->lastc[1] = g_parsefile->lastc[0];
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g_parsefile->lastc[0] = c;
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return c;
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}
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#if ENABLE_ASH_ALIAS
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static int
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@ -9977,11 +9990,11 @@ pgetc_without_PEOA(void)
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{
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int c;
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do {
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pgetc_debug("pgetc_fast at %d:%p'%s'",
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pgetc_debug("pgetc at %d:%p'%s'",
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g_parsefile->left_in_line,
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g_parsefile->next_to_pgetc,
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g_parsefile->next_to_pgetc);
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c = pgetc_fast();
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c = pgetc();
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} while (c == PEOA);
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return c;
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}
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@ -10015,18 +10028,13 @@ pfgets(char *line, int len)
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}
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/*
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* Undo the last call to pgetc. Only one character may be pushed back.
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* Undo a call to pgetc. Only two characters may be pushed back.
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* PEOF may be pushed back.
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*/
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static void
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pungetc(void)
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{
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g_parsefile->left_in_line++;
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g_parsefile->next_to_pgetc--;
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pgetc_debug("pushed back to %d:%p'%s'",
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g_parsefile->left_in_line,
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g_parsefile->next_to_pgetc,
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g_parsefile->next_to_pgetc);
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g_parsefile->unget++;
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}
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/*
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@ -10043,6 +10051,7 @@ pushfile(void)
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pf->pf_fd = -1;
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/*pf->strpush = NULL; - ckzalloc did it */
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/*pf->basestrpush.prev = NULL;*/
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/*pf->unget = 0;*/
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g_parsefile = pf;
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}
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@ -11451,7 +11460,7 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
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IF_ASH_ALIAS(if (c != PEOA))
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USTPUTC(c, out);
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}
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c = pgetc_fast();
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c = pgetc();
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} /* for (;;) */
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endword:
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@ -11945,7 +11954,7 @@ xxreadtoken(void)
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setprompt_if(needprompt, 2);
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startlinno = g_parsefile->linno;
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for (;;) { /* until token or start of word found */
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c = pgetc_fast();
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c = pgetc();
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if (c == ' ' || c == '\t' IF_ASH_ALIAS( || c == PEOA))
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continue;
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@ -12008,7 +12017,7 @@ xxreadtoken(void)
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setprompt_if(needprompt, 2);
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startlinno = g_parsefile->linno;
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for (;;) { /* until token or start of word found */
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c = pgetc_fast();
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c = pgetc();
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switch (c) {
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case ' ': case '\t':
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IF_ASH_ALIAS(case PEOA:)
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