[PATCH] ash/hush: implement -d DELIM option for `read`

[Johannes Schindelin]

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.

Signed-off-by: Johannes Schindelin <johannes.schindelin at gmx.de>
---
Published-As: https://github.com/dscho/busybox-w32/releases/tag/busybox-read-d-v1
Fetch-It-Via: git fetch https://github.com/dscho/busybox-w32 busybox-read-d-v1
 shell/ash.c          | 11 ++++++++---
 shell/hush.c         |  7 +++++--
 shell/shell_common.c | 10 +++++++---
 shell/shell_common.h |  3 ++-
 4 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/shell/ash.c b/shell/ash.c
index e8f3ed26b..b4f6dc3df 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -13402,10 +13402,10 @@ 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 +13415,12 @@ 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;
 	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 +13440,9 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 		case 'u':
 			opt_u = optionarg;
 			break;
+		case 'd':
+			opt_d = optionarg;
+			break;
 		default:
 			break;
 		}
@@ -13456,7 +13460,8 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 		opt_n,
 		opt_p,
 		opt_t,
-		opt_u
+		opt_u,
+		opt_d
 	);
 	INT_ON;
 
diff --git a/shell/hush.c b/shell/hush.c
index bb80f422c..efa518a89 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -9434,13 +9434,15 @@ static int FAST_FUNC builtin_read(char **argv)
 	char *opt_p = NULL;
 	char *opt_t = NULL;
 	char *opt_u = NULL;
+	char *opt_d = NULL;
 	const char *ifs;
 	int read_flags;
 
 	/* "!": do not abort on errors.
 	 * Option string must start with "sr" to match BUILTIN_READ_xxx
 	 */
-	read_flags = getopt32(argv, "!srn:p:t:u:", &opt_n, &opt_p, &opt_t, &opt_u);
+	read_flags = getopt32(argv, "!srn:p:t:u:d:", &opt_n, &opt_p, &opt_t,
+		&opt_u, &opt_d);
 	if (read_flags == (uint32_t)-1)
 		return EXIT_FAILURE;
 	argv += optind;
@@ -9454,7 +9456,8 @@ static int FAST_FUNC builtin_read(char **argv)
 		opt_n,
 		opt_p,
 		opt_t,
-		opt_u
+		opt_u,
+		opt_d
 	);
 
 	if ((uintptr_t)r == 1 && errno == EINTR) {
diff --git a/shell/shell_common.c b/shell/shell_common.c
index a9f8d8413..2db8ea3e2 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -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) {
diff --git a/shell/shell_common.h b/shell/shell_common.h
index a82535c86..1b79bffca 100644
--- a/shell/shell_common.h
+++ b/shell/shell_common.h
@@ -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

base-commit: 4dea1edd08a45c5987448719e56ee61a20fb9210
-- 
2.14.0.windows.1.2.g0f3342804fc