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/* vi: set sw=4 ts=4: */
/*
* Adapted from ash applet code
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Copyright (c) 1989, 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
* was re-ported from NetBSD and debianized.
*
* Copyright (c) 2010 Denys Vlasenko
* Split from ash.c
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
#include "libbb.h"
#include "shell_common.h"
#include "builtin_read.h"
//TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL"
//string. hush naturally has it, and ash has setvareq().
//Here we can simply store "VAR=" at buffer start and store read data directly
//after "=", then pass buffer to setvar() to consume.
const char* FAST_FUNC
shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
char **argv,
const char *ifs,
int read_flags,
const char *opt_n,
const char *opt_p,
const char *opt_t,
const char *opt_u
)
{
unsigned end_ms; /* -t TIMEOUT */
int fd; /* -u FD */
int nchars; /* -n NUM */
char *buffer;
struct termios tty, old_tty;
const char *retval;
int bufpos; /* need to be able to hold -1 */
int startword;
smallint backslash;
nchars = 0; /* if != 0, -n is in effect */
if (opt_n) {
nchars = bb_strtou(opt_n, NULL, 10);
if (nchars < 0 || errno)
return "invalid count";
/* note: "-n 0": off (bash 3.2 does this too) */
}
end_ms = 0;
if (opt_t) {
end_ms = bb_strtou(opt_t, NULL, 10);
if (errno || end_ms > UINT_MAX / 2048)
return "invalid timeout";
end_ms *= 1000;
#if 0 /* even bash has no -t N.NNN support */
ts.tv_sec = bb_strtou(opt_t, &p, 10);
ts.tv_usec = 0;
/* EINVAL means number is ok, but not terminated by NUL */
if (*p == '.' && errno == EINVAL) {
char *p2;
if (*++p) {
int scale;
ts.tv_usec = bb_strtou(p, &p2, 10);
if (errno)
return "invalid timeout";
scale = p2 - p;
/* normalize to usec */
if (scale > 6)
return "invalid timeout";
while (scale++ < 6)
ts.tv_usec *= 10;
}
} else if (ts.tv_sec < 0 || errno) {
return "invalid timeout";
}
if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
return "invalid timeout";
}
#endif /* if 0 */
}
fd = STDIN_FILENO;
if (opt_u) {
fd = bb_strtou(opt_u, NULL, 10);
if (fd < 0 || errno)
return "invalid file descriptor";
}
if (opt_p && isatty(fd)) {
fputs(opt_p, stderr);
fflush_all();
}
if (ifs == NULL)
ifs = defifs;
if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
tcgetattr(fd, &tty);
old_tty = tty;
if (nchars) {
tty.c_lflag &= ~ICANON;
tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
}
if (read_flags & BUILTIN_READ_SILENT) {
tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
}
/* This forces execution of "restoring" tcgetattr later */
read_flags |= BUILTIN_READ_SILENT;
/* if tcgetattr failed, tcsetattr will fail too.
* Ignoring, it's harmless. */
tcsetattr(fd, TCSANOW, &tty);
}
retval = (const char *)(uintptr_t)0;
startword = 1;
backslash = 0;
if (end_ms) /* NB: end_ms stays nonzero: */
end_ms = ((unsigned)monotonic_ms() + end_ms) | 1;
buffer = NULL;
bufpos = 0;
do {
char c;
if (end_ms) {
int timeout;
struct pollfd pfd[1];
pfd[0].fd = fd;
pfd[0].events = POLLIN;
timeout = end_ms - (unsigned)monotonic_ms();
if (timeout <= 0 /* already late? */
|| safe_poll(pfd, 1, timeout) != 1 /* no? wait... */
) { /* timed out! */
retval = (const char *)(uintptr_t)1;
goto ret;
}
}
if ((bufpos & 0xff) == 0)
buffer = xrealloc(buffer, bufpos + 0x100);
if (nonblock_safe_read(fd, &buffer[bufpos], 1) != 1) {
retval = (const char *)(uintptr_t)1;
break;
}
c = buffer[bufpos];
if (c == '\0')
continue;
if (backslash) {
backslash = 0;
if (c != '\n')
goto put;
continue;
}
if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
backslash = 1;
continue;
}
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]) {
/* 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) {
if (isspace(c))
continue;
/* it is a non-space ifs char */
startword--;
if (startword == 1) /* first one? */
continue; /* yes, it is not next word yet */
}
startword = 0;
if (argv[1] != NULL && is_ifs) {
buffer[bufpos] = '\0';
bufpos = 0;
setvar(*argv, buffer);
argv++;
/* can we skip one non-space ifs char? (2: yes) */
startword = isspace(c) ? 2 : 1;
continue;
}
}
put:
bufpos++;
} while (--nchars);
if (argv[0]) {
/* Remove trailing space $IFS chars */
while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
continue;
buffer[bufpos + 1] = '\0';
/* Use the remainder as a value for the next variable */
setvar(*argv, buffer);
/* Set the rest to "" */
while (*++argv)
setvar(*argv, "");
} else {
/* Note: no $IFS removal */
buffer[bufpos] = '\0';
setvar("REPLY", buffer);
}
ret:
free(buffer);
if (read_flags & BUILTIN_READ_SILENT)
tcsetattr(fd, TCSANOW, &old_tty);
return retval;
}
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