From ab3c568fd869e84a7862f3450a4690d3d7b60704 Mon Sep 17 00:00:00 2001
From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Sun, 2 Dec 2018 16:32:36 +0100
Subject: [PATCH] bc: simplify ^C handling
It's still buggy: if SIGINT would interrupt e.g. output write(),
the result would not be as intended:
>>> while ( 1 ) print 1
...
11111111111111111111111111111111111111111111111111111111111111111111\
11111111111111111111111111111111111111111111111111111111111111111111\
^Cready for more input
interrupt (type "quit" to exit)
>>> bc: output error
function old new delta
dc_parse_parse 58 53 -5
bc_parse_parse 476 471 -5
bc_num_d 609 604 -5
bc_num_cmp 299 294 -5
bc_num_compare 90 84 -6
bc_parse_expr 2222 2215 -7
bc_num_subArrays 82 74 -8
dc_main 72 62 -10
bc_main 72 62 -10
bc_program_exec 4413 4401 -12
bc_num_a 491 474 -17
bc_read_line 364 344 -20
bc_num_p 540 518 -22
bc_program_reset 192 168 -24
bc_num_k 1031 1005 -26
bc_vm_run 2382 2317 -65
bc_vm_sig 97 - -97
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 0/16 up/down: 0/-344) Total: -344 bytes
text data bss dec hex filename
989372 485 7296 997153 f3721 busybox_old
989028 485 7296 996809 f35c9 busybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---
miscutils/bc.c | 139 +++++++++++++++++++++----------------------------
1 file changed, 59 insertions(+), 80 deletions(-)
diff --git a/miscutils/bc.c b/miscutils/bc.c
index e13b2283c..72afb6808 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -826,16 +826,8 @@ struct globals {
char *env_args;
- unsigned sig; //counter?
- unsigned sigc; //counter?
- smallint signe; //flag
-
smallint tty;
smallint ttyin;
-
-#if ENABLE_FEATURE_BC_SIGNALS
- const char *sig_msg;
-#endif
} FIX_ALIASING;
#define G (*ptr_to_globals)
#define INIT_G() do { \
@@ -844,6 +836,7 @@ struct globals {
#define G_posix (ENABLE_BC && (G.flags & BC_FLAG_S))
#define G_warn (ENABLE_BC && (G.flags & BC_FLAG_W))
#define G_exreg (ENABLE_DC && (G.flags & BC_FLAG_X))
+#define G_interrupt (ENABLE_FEATURE_BC_SIGNALS ? bb_got_signal : 0)
#define IS_BC (ENABLE_BC && (!ENABLE_DC || applet_name[0] == 'b'))
@@ -1349,36 +1342,47 @@ static BcStatus bc_read_line(BcVec *vec, const char *prompt)
int i;
signed char c;
- if (G.ttyin && !G_posix) {
- fputs(prompt, stderr);
- fflush(stderr);
- }
-
bc_vec_npop(vec, vec->len);
+ fflush(stdout);
+#if ENABLE_FEATURE_BC_SIGNALS
+ if (bb_got_signal) { /* ^C was pressed */
+ intr:
+ fputs(IS_BC
+ ? "\ninterrupt (type \"quit\" to exit)\n"
+ : "\ninterrupt (type \"q\" to exit)\n"
+ , stderr);
+ }
+ bb_got_signal = 0; /* resets G_interrupt to zero */
+#endif
+ if (G.ttyin && !G_posix)
+ fputs(prompt, stderr);
+ fflush(stderr);
+
+#if ENABLE_FEATURE_BC_SIGNALS
+ again:
+ errno = 0;
+#endif
do {
if (ferror(stdout) || ferror(stderr))
bb_perror_msg_and_die("output error");
- errno = 0;
i = fgetc(stdin);
+#if ENABLE_FEATURE_BC_SIGNALS
+ if (bb_got_signal) /* ^C was pressed */
+ goto intr;
+#endif
+
if (i == EOF) {
#if ENABLE_FEATURE_BC_SIGNALS
if (errno == EINTR) {
- G.sigc = G.sig;
- G.signe = 0;
- if (G.ttyin) {
- fputs(bc_program_ready_msg, stderr);
- if (!G_posix) fputs(prompt, stderr);
- fflush(stderr);
- }
clearerr(stdin);
- continue;
+ goto again;
}
+#endif
if (ferror(stdin))
bb_perror_msg_and_die("input error");
-#endif
return BC_STATUS_INPUT_EOF;
}
@@ -1471,20 +1475,20 @@ static BcStatus bc_num_subArrays(BcDig *restrict a, BcDig *restrict b,
size_t len)
{
size_t i, j;
- for (i = 0; !G.signe && i < len; ++i) {
- for (a[i] -= b[i], j = 0; !G.signe && a[i + j] < 0;) {
+ for (i = 0; !G_interrupt && i < len; ++i) {
+ for (a[i] -= b[i], j = 0; !G_interrupt && a[i + j] < 0;) {
a[i + j++] += 10;
a[i + j] -= 1;
}
}
- return G.signe ? BC_STATUS_EXEC_SIGNAL : BC_STATUS_SUCCESS;
+ return G_interrupt ? BC_STATUS_EXEC_SIGNAL : BC_STATUS_SUCCESS;
}
static ssize_t bc_num_compare(BcDig *restrict a, BcDig *restrict b, size_t len)
{
size_t i;
int c = 0;
- for (i = len - 1; !G.signe && i < len && !(c = a[i] - b[i]); --i);
+ for (i = len - 1; !G_interrupt && i < len && !(c = a[i] - b[i]); --i);
return BC_NUM_NEG(i + 1, c < 0);
}
@@ -1530,7 +1534,7 @@ static ssize_t bc_num_cmp(BcNum *a, BcNum *b)
cmp = bc_num_compare(max_num, min_num, b_int + min);
if (cmp != 0) return BC_NUM_NEG(cmp, (!a_max) != neg);
- for (max_num -= diff, i = diff - 1; !G.signe && i < diff; --i) {
+ for (max_num -= diff, i = diff - 1; !G_interrupt && i < diff; --i) {
if (max_num[i]) return BC_NUM_NEG(1, (!a_max) != neg);
}
@@ -1689,13 +1693,13 @@ static BcStatus bc_num_a(BcNum *a, BcNum *b, BcNum *restrict c, size_t sub)
ptr = ptr_b;
}
- for (carry = 0, i = 0; !G.signe && i < min_rdx + min_int; ++i, ++c->len) {
+ for (carry = 0, i = 0; !G_interrupt && i < min_rdx + min_int; ++i, ++c->len) {
in = ((int) ptr_a[i]) + ((int) ptr_b[i]) + carry;
carry = in / 10;
ptr_c[i] = (BcDig)(in % 10);
}
- for (; !G.signe && i < max + min_rdx; ++i, ++c->len) {
+ for (; !G_interrupt && i < max + min_rdx; ++i, ++c->len) {
in = ((int) ptr[i]) + carry;
carry = in / 10;
ptr_c[i] = (BcDig)(in % 10);
@@ -1703,7 +1707,7 @@ static BcStatus bc_num_a(BcNum *a, BcNum *b, BcNum *restrict c, size_t sub)
if (carry != 0) c->num[c->len++] = (BcDig) carry;
- return G.signe ? BC_STATUS_EXEC_SIGNAL : BC_STATUS_SUCCESS;
+ return G_interrupt ? BC_STATUS_EXEC_SIGNAL : BC_STATUS_SUCCESS;
}
static BcStatus bc_num_s(BcNum *a, BcNum *b, BcNum *restrict c, size_t sub)
@@ -1778,7 +1782,7 @@ static BcStatus bc_num_k(BcNum *restrict a, BcNum *restrict b,
BcNum l1, h1, l2, h2, m2, m1, z0, z1, z2, temp;
bool aone = BC_NUM_ONE(a);
- if (G.signe) return BC_STATUS_EXEC_SIGNAL;
+ if (G_interrupt) return BC_STATUS_EXEC_SIGNAL;
if (a->len == 0 || b->len == 0) {
bc_num_zero(c);
return BC_STATUS_SUCCESS;
@@ -1796,9 +1800,9 @@ static BcStatus bc_num_k(BcNum *restrict a, BcNum *restrict b,
memset(c->num, 0, sizeof(BcDig) * c->cap);
c->len = carry = len = 0;
- for (i = 0; !G.signe && i < b->len; ++i) {
+ for (i = 0; !G_interrupt && i < b->len; ++i) {
- for (j = 0; !G.signe && j < a->len; ++j) {
+ for (j = 0; !G_interrupt && j < a->len; ++j) {
int in = (int) c->num[i + j];
in += ((int) a->num[j]) * ((int) b->num[i]) + carry;
carry = in / 10;
@@ -1812,7 +1816,7 @@ static BcStatus bc_num_k(BcNum *restrict a, BcNum *restrict b,
c->len = len;
- return G.signe ? BC_STATUS_EXEC_SIGNAL : BC_STATUS_SUCCESS;
+ return G_interrupt ? BC_STATUS_EXEC_SIGNAL : BC_STATUS_SUCCESS;
}
bc_num_init(&l1, max);
@@ -1962,7 +1966,7 @@ static BcStatus bc_num_d(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale)
c->len = cp.len;
p = b->num;
- for (i = end - 1; !G.signe && !s && i < end; --i) {
+ for (i = end - 1; !G_interrupt && !s && i < end; --i) {
n = cp.num + i;
for (q = 0; (!s && n[len] != 0) || bc_num_compare(n, p, len) >= 0; ++q)
s = bc_num_subArrays(n, p, len);
@@ -2062,20 +2066,20 @@ static BcStatus bc_num_p(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale)
b->neg = neg;
- for (powrdx = a->rdx; !G.signe && !(pow & 1); pow >>= 1) {
+ for (powrdx = a->rdx; !G_interrupt && !(pow & 1); pow >>= 1) {
powrdx <<= 1;
s = bc_num_mul(©, ©, ©, powrdx);
if (s) goto err;
}
- if (G.signe) {
+ if (G_interrupt) {
s = BC_STATUS_EXEC_SIGNAL;
goto err;
}
bc_num_copy(c, ©);
- for (resrdx = powrdx, pow >>= 1; !G.signe && pow != 0; pow >>= 1) {
+ for (resrdx = powrdx, pow >>= 1; !G_interrupt && pow != 0; pow >>= 1) {
powrdx <<= 1;
s = bc_num_mul(©, ©, ©, powrdx);
@@ -2093,7 +2097,7 @@ static BcStatus bc_num_p(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale)
if (s) goto err;
}
- if (G.signe) {
+ if (G_interrupt) {
s = BC_STATUS_EXEC_SIGNAL;
goto err;
}
@@ -2650,7 +2654,7 @@ static BcStatus bc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
resrdx = scale + 2;
len = BC_NUM_INT(x0) + resrdx - 1;
- while (!G.signe && (cmp != 0 || digs < len)) {
+ while (!G_interrupt && (cmp != 0 || digs < len)) {
s = bc_num_div(a, x0, &f, resrdx);
if (s) goto err;
@@ -2678,7 +2682,7 @@ static BcStatus bc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
x1 = temp;
}
- if (G.signe) {
+ if (G_interrupt) {
s = BC_STATUS_EXEC_SIGNAL;
goto err;
}
@@ -4775,7 +4779,7 @@ static BcStatus bc_parse_parse(BcParse *p)
else
s = bc_parse_stmt(p);
- if ((s && s != BC_STATUS_QUIT && s != BC_STATUS_LIMITS) || G.signe)
+ if ((s && s != BC_STATUS_QUIT && s != BC_STATUS_LIMITS) || G_interrupt)
s = bc_parse_reset(p, s);
return s;
@@ -4795,7 +4799,7 @@ static BcStatus bc_parse_expr(BcParse *p, uint8_t flags, BcParseNext next)
paren_expr = rprn = done = get_token = assign = false;
bin_last = true;
- for (; !G.signe && !s && !done && bc_parse_exprs[t]; t = p->l.t.t) {
+ for (; !G_interrupt && !s && !done && bc_parse_exprs[t]; t = p->l.t.t) {
switch (t) {
case BC_LEX_OP_INC:
@@ -4989,7 +4993,7 @@ static BcStatus bc_parse_expr(BcParse *p, uint8_t flags, BcParseNext next)
}
if (s) return s;
- if (G.signe) return BC_STATUS_EXEC_SIGNAL;
+ if (G_interrupt) return BC_STATUS_EXEC_SIGNAL;
while (p->ops.len > ops_bgn) {
@@ -5249,7 +5253,7 @@ static BcStatus dc_parse_parse(BcParse *p)
else
s = dc_parse_expr(p, 0);
- if (s || G.signe) s = bc_parse_reset(p, s);
+ if (s || G_interrupt) s = bc_parse_reset(p, s);
return s;
}
@@ -6632,13 +6636,11 @@ static BcStatus bc_program_reset(BcProgram *p, BcStatus s)
ip = bc_vec_top(&p->stack);
ip->idx = f->code.len;
- if (!s && G.signe && !G.tty) return BC_STATUS_QUIT;
-
- G.sigc += G.signe;
- G.signe = G.sig != G.sigc;
+ if (!s && G_interrupt && !G.tty) return BC_STATUS_QUIT;
if (!s || s == BC_STATUS_EXEC_SIGNAL) {
if (G.ttyin) {
+ fflush(stdout);
fputs(bc_program_ready_msg, stderr);
fflush(stderr);
s = BC_STATUS_SUCCESS;
@@ -6959,7 +6961,7 @@ static BcStatus bc_program_exec(BcProgram *p)
#endif // ENABLE_DC
}
- if ((s && s != BC_STATUS_QUIT) || G.signe) s = bc_program_reset(p, s);
+ if ((s && s != BC_STATUS_QUIT) || G_interrupt) s = bc_program_reset(p, s);
// If the stack has changed, pointers may be invalid.
ip = bc_vec_top(&p->stack);
@@ -6970,19 +6972,6 @@ static BcStatus bc_program_exec(BcProgram *p)
return s;
}
-#if ENABLE_FEATURE_BC_SIGNALS
-static void bc_vm_sig(int sig)
-{
- int err = errno;
- size_t len = strlen(G.sig_msg);
- if (sig == SIGINT && write(2, G.sig_msg, len) == (ssize_t) len) {
- G.signe = G.sig == G.sigc;
- G.sig += G.signe;
- }
- errno = err;
-}
-#endif
-
static void bc_vm_info(void)
{
printf("%s "BB_VER"\n"
@@ -7268,21 +7257,17 @@ static void bc_vm_free(void)
static void bc_vm_init(const char *env_len)
{
size_t len = bc_vm_envLen(env_len);
-#if ENABLE_FEATURE_BC_SIGNALS
- struct sigaction sa;
- sigemptyset(&sa.sa_mask);
- sa.sa_handler = bc_vm_sig;
- sa.sa_flags = 0;
- sigaction(SIGINT, &sa, NULL);
+#if ENABLE_FEATURE_BC_SIGNALS
+ signal_no_SA_RESTART_empty_mask(SIGINT, record_signo);
#endif
bc_vec_init(&G.files, sizeof(char *), NULL);
-#if ENABLE_BC
- G.flags |= BC_FLAG_S * IS_BC * (getenv("POSIXLY_CORRECT") != NULL);
- if (IS_BC) bc_vm_envArgs();
-#endif
+ if (IS_BC) {
+ G.flags |= BC_FLAG_S * (getenv("POSIXLY_CORRECT") != NULL);
+ bc_vm_envArgs();
+ }
bc_program_init(&G.prog, len, G.init, G.exp);
G.init(&G.prs, &G.prog, BC_PROG_MAIN);
@@ -7311,9 +7296,6 @@ int bc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int bc_main(int argc, char **argv)
{
INIT_G();
-# if ENABLE_FEATURE_BC_SIGNALS
- G.sig_msg = "\ninterrupt (type \"quit\" to exit)\n";
-# endif
G.init = bc_parse_init;
G.exp = bc_parse_expression;
G.sbgn = G.send = '"';
@@ -7327,9 +7309,6 @@ int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dc_main(int argc, char **argv)
{
INIT_G();
-# if ENABLE_FEATURE_BC_SIGNALS
- G.sig_msg = "\ninterrupt (type \"q\" to exit)\n";
-# endif
G.init = dc_parse_init;
G.exp = dc_parse_expr;
G.sbgn = '[';
--
2.25.1