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ash: implement -d DELIM option for read

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The POSIX standard only requires the read builtin to handle -r:
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/read.html

However, Bash introduced the option -d <DELIM> to override IFS for
just one invocation, and it is quite useful.

It is also super easy to implement in BusyBox' ash, so let's do that.

The motivation: This option is used by Git's test suite.

function                                             old     new   delta
.rodata                                           163505  163587     +82
shell_builtin_read                                  1244    1289     +45
readcmd                                              233     259     +26
builtin_read                                         258     263      +5
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 158/0)             Total: 158 bytes

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Johannes Schindelin 2017-08-08 16:46:39 +02:00 committed by Denys Vlasenko
parent 5856dc74be
commit 3bef5d89b0
3 changed files with 21 additions and 7 deletions
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15
shell/ash.c
View File

@ -189,6 +189,8 @@
#define BASH_HOSTNAME_VAR ENABLE_ASH_BASH_COMPAT
#define BASH_SHLVL_VAR ENABLE_ASH_BASH_COMPAT
#define BASH_XTRACEFD ENABLE_ASH_BASH_COMPAT
#define BASH_READ_D ENABLE_ASH_BASH_COMPAT
#define IF_BASH_READ_D IF_ASH_BASH_COMPAT
#if defined(__ANDROID_API__) && __ANDROID_API__ <= 24
/* Bionic at least up to version 24 has no glob() */
@ -13402,10 +13404,10 @@ letcmd(int argc UNUSED_PARAM, char **argv)
* -p PROMPT Display PROMPT on stderr (if input is from tty)
* -t SECONDS Timeout after SECONDS (tty or pipe only)
* -u FD Read from given FD instead of fd 0
* -d DELIM End on DELIM char, not newline
* This uses unbuffered input, which may be avoidable in some cases.
* TODO: bash also has:
* -a ARRAY Read into array[0],[1],etc
* -d DELIM End on DELIM char, not newline
* -e Use line editing (tty only)
*/
static int FAST_FUNC
@ -13415,11 +13417,12 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
char *opt_p = NULL;
char *opt_t = NULL;
char *opt_u = NULL;
char *opt_d = NULL; /* optimized out if !BASH */
int read_flags = 0;
const char *r;
int i;
while ((i = nextopt("p:u:rt:n:s")) != '\0') {
while ((i = nextopt("p:u:rt:n:sd:")) != '\0') {
switch (i) {
case 'p':
opt_p = optionarg;
@ -13439,6 +13442,11 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
case 'u':
opt_u = optionarg;
break;
#if BASH_READ_D
case 'd':
opt_d = optionarg;
break;
#endif
default:
break;
}
@ -13456,7 +13464,8 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
opt_n,
opt_p,
opt_t,
opt_u
opt_u,
opt_d
);
INT_ON;

10
shell/shell_common.c
View File

@ -54,7 +54,8 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
const char *opt_n,
const char *opt_p,
const char *opt_t,
const char *opt_u
const char *opt_u,
const char *opt_d
)
{
struct pollfd pfd[1];
@ -237,14 +238,17 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
continue;
}
}
if (c == '\n')
if (opt_d) {
if (c == *opt_d)
break;
} else if (c == '\n')
break;
/* $IFS splitting. NOT done if we run "read"
* without variable names (bash compat).
* Thus, "read" and "read REPLY" are not the same.
*/
if (argv[0]) {
if (!opt_d && argv[0]) {
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
const char *is_ifs = strchr(ifs, c);
if (startword && is_ifs) {

3
shell/shell_common.h
View File

@ -42,7 +42,8 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
const char *opt_n,
const char *opt_p,
const char *opt_t,
const char *opt_u
const char *opt_u,
const char *opt_d
);
int FAST_FUNC