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-rw-r--r--shell/ash.c122
1 files changed, 67 insertions, 55 deletions
diff --git a/shell/ash.c b/shell/ash.c
index d9ce202fd..2b6133d20 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -11672,10 +11672,18 @@ typedef enum __rlimit_resource rlim_t;
#endif
/*
- * The read builtin. The -e option causes backslashes to escape the
- * following character.
- *
+ * The read builtin. Options:
+ * -r Do not interpret '\' specially
+ * -s Turn off echo (tty only)
+ * -n NCHARS Read NCHARS max
+ * -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
* 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
readcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
@@ -11690,31 +11698,23 @@ readcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
int startword;
int status;
int i;
+ int fd = 0;
#if ENABLE_ASH_READ_NCHARS
- int n_flag = 0;
- int nchars = 0;
+ int nchars = 0; /* if != 0, -n is in effect */
int silent = 0;
struct termios tty, old_tty;
#endif
#if ENABLE_ASH_READ_TIMEOUT
- fd_set set;
- struct timeval ts;
-
- ts.tv_sec = ts.tv_usec = 0;
+ unsigned end_ms = 0;
+ unsigned timeout = 0;
#endif
rflag = 0;
prompt = NULL;
-#if ENABLE_ASH_READ_NCHARS && ENABLE_ASH_READ_TIMEOUT
- while ((i = nextopt("p:rt:n:s")) != '\0')
-#elif ENABLE_ASH_READ_NCHARS
- while ((i = nextopt("p:rn:s")) != '\0')
-#elif ENABLE_ASH_READ_TIMEOUT
- while ((i = nextopt("p:rt:")) != '\0')
-#else
- while ((i = nextopt("p:r")) != '\0')
-#endif
- {
+ while ((i = nextopt("p:u:r"
+ USE_ASH_READ_TIMEOUT("t:")
+ USE_ASH_READ_NCHARS("n:s")
+ )) != '\0') {
switch (i) {
case 'p':
prompt = optionarg;
@@ -11724,7 +11724,7 @@ readcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
nchars = bb_strtou(optionarg, NULL, 10);
if (nchars < 0 || errno)
ash_msg_and_raise_error("invalid count");
- n_flag = nchars; /* just a flag "nchars is nonzero" */
+ /* nchars == 0: off (bash 3.2 does this too) */
break;
case 's':
silent = 1;
@@ -11732,6 +11732,11 @@ readcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
#endif
#if ENABLE_ASH_READ_TIMEOUT
case 't':
+ timeout = bb_strtou(optionarg, NULL, 10);
+ if (errno || timeout > UINT_MAX / 2048)
+ ash_msg_and_raise_error("invalid timeout");
+ timeout *= 1000;
+#if 0 /* even bash have no -t N.NNN support */
ts.tv_sec = bb_strtou(optionarg, &p, 10);
ts.tv_usec = 0;
/* EINVAL means number is ok, but not terminated by NUL */
@@ -11755,16 +11760,22 @@ readcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
ash_msg_and_raise_error("invalid timeout");
}
+#endif /* if 0 */
break;
#endif
case 'r':
rflag = 1;
break;
+ case 'u':
+ fd = bb_strtou(optionarg, NULL, 10);
+ if (fd < 0 || errno)
+ ash_msg_and_raise_error("invalid file descriptor");
+ break;
default:
break;
}
}
- if (prompt && isatty(0)) {
+ if (prompt && isatty(fd)) {
out2str(prompt);
}
ap = argptr;
@@ -11774,46 +11785,48 @@ readcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
if (ifs == NULL)
ifs = defifs;
#if ENABLE_ASH_READ_NCHARS
- if (n_flag || silent) {
- if (tcgetattr(0, &tty) != 0) {
- /* Not a tty */
- n_flag = 0;
- silent = 0;
- } else {
- old_tty = tty;
- if (n_flag) {
- tty.c_lflag &= ~ICANON;
- tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
- }
- if (silent) {
- tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
- }
- tcsetattr(0, TCSANOW, &tty);
+ tcgetattr(fd, &tty);
+ old_tty = tty;
+ if (nchars || silent) {
+ if (nchars) {
+ tty.c_lflag &= ~ICANON;
+ tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
}
- }
-#endif
-#if ENABLE_ASH_READ_TIMEOUT
- if (ts.tv_sec || ts.tv_usec) {
- FD_ZERO(&set);
- FD_SET(0, &set);
-
- /* poll-based wait produces bigger code, using select */
- i = select(1, &set, NULL, NULL, &ts);
- if (!i) { /* timed out! */
-#if ENABLE_ASH_READ_NCHARS
- if (n_flag)
- tcsetattr(0, TCSANOW, &old_tty);
-#endif
- return 1;
+ if (silent) {
+ tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
}
+ /* if tcgetattr failed, tcsetattr will fail too.
+ * Ignoring, it's harmless. */
+ tcsetattr(fd, TCSANOW, &tty);
}
#endif
+
status = 0;
startword = 1;
backslash = 0;
+#if ENABLE_ASH_READ_TIMEOUT
+ if (timeout) /* NB: ensuring end_ms is nonzero */
+ end_ms = ((unsigned)(monotonic_us() / 1000) + timeout) | 1;
+#endif
STARTSTACKSTR(p);
do {
- if (nonblock_safe_read(0, &c, 1) != 1) {
+#if ENABLE_ASH_READ_TIMEOUT
+ if (end_ms) {
+ struct pollfd pfd[1];
+ pfd[0].fd = fd;
+ pfd[0].events = POLLIN;
+ timeout = end_ms - (unsigned)(monotonic_us() / 1000);
+ if ((int)timeout <= 0 /* already late? */
+ || safe_poll(pfd, 1, timeout) != 1 /* no? wait... */
+ ) { /* timed out! */
+#if ENABLE_ASH_READ_NCHARS
+ tcsetattr(fd, TCSANOW, &old_tty);
+#endif
+ return 1;
+ }
+ }
+#endif
+ if (nonblock_safe_read(fd, &c, 1) != 1) {
status = 1;
break;
}
@@ -11848,14 +11861,13 @@ readcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
}
/* end of do {} while: */
#if ENABLE_ASH_READ_NCHARS
- while (!n_flag || --nchars);
+ while (--nchars);
#else
while (1);
#endif
#if ENABLE_ASH_READ_NCHARS
- if (n_flag || silent)
- tcsetattr(0, TCSANOW, &old_tty);
+ tcsetattr(fd, TCSANOW, &old_tty);
#endif
STACKSTRNUL(p);