ash: add process substitution in bash-compatibility mode
Process substitution is a Korn shell feature that's also available
in bash and some other shells. This patch implements process
substitution in ash when ASH_BASH_COMPAT is enabled.
function old new delta
argstr 1386 1522 +136
strtodest - 52 +52
readtoken1 3346 3392 +46
.rodata 183206 183250 +44
unwindredir - 28 +28
cmdloop 365 372 +7
static.spclchars 10 12 +2
cmdputs 380 367 -13
exitreset 86 69 -17
evalcommand 1754 1737 -17
varvalue 675 634 -41
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 5/4 up/down: 315/-88) Total: 227 bytes
text data bss dec hex filename
953967 4219 1904 960090 ea65a busybox_old
954192 4219 1904 960315 ea73b busybox_unstripped
v2: Replace array of file descriptors with a linked list.
Include tests that were unaccountably omitted from v1.
v3: Update linked list code to the intended version.
v4: Change order of conditional code in cmdputs().
v5: Use existing popredir() mechanism to manage file descriptors.
v6: Rebase to latest version of BusyBox ash. Reduce code churn.
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Ron Yorston
Denys Vlasenko
parent
8c1f8aa016
commit
a1b0d3856d
@ -426,6 +426,8 @@ typedef unsigned smalluint;
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#define HAVE_SYS_STATFS_H 1
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#define HAVE_PRINTF_PERCENTM 1
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#define HAVE_WAIT3 1
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#define HAVE_DEV_FD 1
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#define DEV_FD_PREFIX "/dev/fd/"
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#if defined(__UCLIBC__)
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# if UCLIBC_VERSION < KERNEL_VERSION(0, 9, 32)
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158
shell/ash.c
158
shell/ash.c
@ -229,6 +229,14 @@
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#define BASH_READ_D ENABLE_ASH_BASH_COMPAT
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#define IF_BASH_READ_D IF_ASH_BASH_COMPAT
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#define BASH_WAIT_N ENABLE_ASH_BASH_COMPAT
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/* <(...) and >(...) */
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#if HAVE_DEV_FD
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# define BASH_PROCESS_SUBST ENABLE_ASH_BASH_COMPAT
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# define IF_BASH_PROCESS_SUBST IF_ASH_BASH_COMPAT
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#else
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# define BASH_PROCESS_SUBST 0
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# define IF_BASH_PROCESS_SUBST(...)
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#endif
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#if defined(__ANDROID_API__) && __ANDROID_API__ <= 24
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/* Bionic at least up to version 24 has no glob() */
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@ -804,6 +812,12 @@ out2str(const char *p)
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#define CTLENDARI ((unsigned char)'\207')
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#define CTLQUOTEMARK ((unsigned char)'\210')
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#define CTL_LAST CTLQUOTEMARK
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#if BASH_PROCESS_SUBST
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# define CTLTOPROC ((unsigned char)'\211')
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# define CTLFROMPROC ((unsigned char)'\212')
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# undef CTL_LAST
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# define CTL_LAST CTLFROMPROC
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#endif
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/* variable substitution byte (follows CTLVAR) */
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#define VSTYPE 0x0f /* type of variable substitution */
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@ -1075,6 +1089,10 @@ trace_puts_quoted(char *s)
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case CTLESC: c = 'e'; goto backslash;
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case CTLVAR: c = 'v'; goto backslash;
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case CTLBACKQ: c = 'q'; goto backslash;
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#if BASH_PROCESS_SUBST
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case CTLTOPROC: c = 'p'; goto backslash;
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case CTLFROMPROC: c = 'P'; goto backslash;
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#endif
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backslash:
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putc('\\', tracefile);
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putc(c, tracefile);
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@ -1236,8 +1254,17 @@ sharg(union node *arg, FILE *fp)
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case CTLENDVAR:
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putc('}', fp);
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break;
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#if BASH_PROCESS_SUBST
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case CTLTOPROC:
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putc('>', fp);
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goto backq;
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case CTLFROMPROC:
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putc('<', fp);
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goto backq;
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#endif
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case CTLBACKQ:
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putc('$', fp);
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IF_BASH_PROCESS_SUBST(backq:)
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putc('(', fp);
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shtree(bqlist->n, -1, NULL, fp);
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putc(')', fp);
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@ -3234,8 +3261,13 @@ static const uint8_t syntax_index_table[] ALIGN1 = {
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/* 134 CTLARI */ CCTL_CCTL_CCTL_CCTL,
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/* 135 CTLENDARI */ CCTL_CCTL_CCTL_CCTL,
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/* 136 CTLQUOTEMARK */ CCTL_CCTL_CCTL_CCTL,
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#if BASH_PROCESS_SUBST
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/* 137 CTLTOPROC */ CCTL_CCTL_CCTL_CCTL,
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/* 138 CTLFROMPROC */ CCTL_CCTL_CCTL_CCTL,
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#else
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/* 137 */ CWORD_CWORD_CWORD_CWORD,
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/* 138 */ CWORD_CWORD_CWORD_CWORD,
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#endif
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/* 139 */ CWORD_CWORD_CWORD_CWORD,
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/* 140 */ CWORD_CWORD_CWORD_CWORD,
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/* 141 */ CWORD_CWORD_CWORD_CWORD,
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@ -4849,9 +4881,24 @@ cmdputs(const char *s)
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quoted >>= 1;
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subtype = 0;
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goto dostr;
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#if BASH_PROCESS_SUBST
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case CTLBACKQ:
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c = '$';
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str = "(...)";
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break;
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case CTLTOPROC:
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c = '>';
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str = "(...)";
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break;
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case CTLFROMPROC:
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c = '<';
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str = "(...)";
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break;
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#else
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case CTLBACKQ:
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str = "$(...)";
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goto dostr;
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#endif
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#if ENABLE_FEATURE_SH_MATH
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case CTLARI:
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str = "$((";
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@ -5891,6 +5938,21 @@ redirectsafe(union node *redir, int flags)
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return err;
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}
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#if BASH_PROCESS_SUBST
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static void
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pushfd(int fd)
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{
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struct redirtab *sv;
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sv = ckzalloc(sizeof(*sv) + sizeof(sv->two_fd[0]));
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sv->pair_count = 1;
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sv->two_fd[0].orig_fd = fd;
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sv->two_fd[0].moved_to = CLOSED;
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sv->next = redirlist;
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redirlist = sv;
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}
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#endif
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static struct redirtab*
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pushredir(union node *redir)
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{
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@ -6529,10 +6591,20 @@ evaltreenr(union node *n, int flags)
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}
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static void FAST_FUNC
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evalbackcmd(union node *n, struct backcmd *result)
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evalbackcmd(union node *n, struct backcmd *result
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IF_BASH_PROCESS_SUBST(, int ctl))
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{
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int pip[2];
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struct job *jp;
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#if BASH_PROCESS_SUBST
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/* determine end of pipe used by parent (ip) and child (ic) */
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const int ip = (ctl == CTLTOPROC);
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const int ic = !(ctl == CTLTOPROC);
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#else
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const int ctl = CTLBACKQ;
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const int ip = 0;
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const int ic = 1;
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#endif
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result->fd = -1;
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result->buf = NULL;
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@ -6544,15 +6616,17 @@ evalbackcmd(union node *n, struct backcmd *result)
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if (pipe(pip) < 0)
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ash_msg_and_raise_perror("can't create pipe");
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jp = makejob(/*n,*/ 1);
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if (forkshell(jp, n, FORK_NOJOB) == 0) {
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/* process substitution uses NULL job/node, like openhere() */
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jp = (ctl == CTLBACKQ) ? makejob(/*n,*/ 1) : NULL;
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if (forkshell(jp, (ctl == CTLBACKQ) ? n : NULL, FORK_NOJOB) == 0) {
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/* child */
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FORCE_INT_ON;
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close(pip[0]);
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if (pip[1] != 1) {
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/*close(1);*/
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dup2_or_raise(pip[1], 1);
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close(pip[1]);
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close(pip[ip]);
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/* ic is index of child end of pipe *and* fd to connect it to */
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if (pip[ic] != ic) {
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/*close(ic);*/
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dup2_or_raise(pip[ic], ic);
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close(pip[ic]);
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}
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/* TODO: eflag clearing makes the following not abort:
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* ash -c 'set -e; z=$(false;echo foo); echo $z'
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@ -6568,8 +6642,18 @@ evalbackcmd(union node *n, struct backcmd *result)
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/* NOTREACHED */
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}
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/* parent */
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close(pip[1]);
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result->fd = pip[0];
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#if BASH_PROCESS_SUBST
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if (ctl != CTLBACKQ) {
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int fd = fcntl(pip[ip], F_DUPFD, 64);
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if (fd > 0) {
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close(pip[ip]);
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pip[ip] = fd;
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}
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pushfd(pip[ip]);
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}
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#endif
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close(pip[ic]);
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result->fd = pip[ip];
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result->jp = jp;
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out:
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@ -6581,8 +6665,11 @@ evalbackcmd(union node *n, struct backcmd *result)
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* Expand stuff in backwards quotes.
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*/
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static void
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expbackq(union node *cmd, int flag)
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expbackq(union node *cmd, int flag IF_BASH_PROCESS_SUBST(, int ctl))
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{
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#if !BASH_PROCESS_SUBST
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const int ctl = CTLBACKQ;
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#endif
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struct backcmd in;
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int i;
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char buf[128];
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@ -6597,9 +6684,15 @@ expbackq(union node *cmd, int flag)
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INT_OFF;
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startloc = expdest - (char *)stackblock();
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pushstackmark(&smark, startloc);
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evalbackcmd(cmd, &in);
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evalbackcmd(cmd, &in IF_BASH_PROCESS_SUBST(, ctl));
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popstackmark(&smark);
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if (ctl != CTLBACKQ) {
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sprintf(buf, DEV_FD_PREFIX"%d", in.fd);
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strtodest(buf, BASESYNTAX);
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goto done;
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}
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p = in.buf;
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i = in.nleft;
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if (i == 0)
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@ -6621,6 +6714,7 @@ expbackq(union node *cmd, int flag)
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close(in.fd);
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back_exitstatus = waitforjob(in.jp);
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}
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done:
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INT_ON;
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/* Eat all trailing newlines */
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@ -6708,6 +6802,10 @@ argstr(char *p, int flag)
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CTLESC,
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CTLVAR,
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CTLBACKQ,
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#if BASH_PROCESS_SUBST
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CTLTOPROC,
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CTLFROMPROC,
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#endif
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#if ENABLE_FEATURE_SH_MATH
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CTLARI,
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CTLENDARI,
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@ -6807,8 +6905,12 @@ argstr(char *p, int flag)
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p = evalvar(p, flag | inquotes);
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TRACE(("argstr: evalvar:'%s'\n", (char *)stackblock()));
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goto start;
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#if BASH_PROCESS_SUBST
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case CTLTOPROC:
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case CTLFROMPROC:
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#endif
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case CTLBACKQ:
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expbackq(argbackq->n, flag | inquotes);
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expbackq(argbackq->n, flag | inquotes IF_BASH_PROCESS_SUBST(, c));
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goto start;
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#if ENABLE_FEATURE_SH_MATH
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case CTLARI:
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@ -12198,8 +12300,9 @@ realeofmark(const char *eofmark)
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#define CHECKEND() {goto checkend; checkend_return:;}
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#define PARSEREDIR() {goto parseredir; parseredir_return:;}
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#define PARSESUB() {goto parsesub; parsesub_return:;}
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#define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
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#define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
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#define PARSEBACKQOLD() {style = OLD; goto parsebackq; parsebackq_oldreturn:;}
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#define PARSEBACKQNEW() {style = NEW; goto parsebackq; parsebackq_newreturn:;}
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#define PARSEPROCSUB() {style = PSUB; goto parsebackq; parsebackq_psreturn:;}
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#define PARSEARITH() {goto parsearith; parsearith_return:;}
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static int
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readtoken1(int c, int syntax, char *eofmark, int striptabs)
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@ -12210,7 +12313,9 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
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size_t len;
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struct nodelist *bqlist;
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smallint quotef;
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smallint oldstyle;
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smallint style;
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enum { OLD, NEW, PSUB };
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#define oldstyle (style == OLD)
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smallint pssyntax; /* we are expanding a prompt string */
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IF_BASH_DOLLAR_SQUOTE(smallint bash_dollar_squote = 0;)
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/* syntax stack */
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@ -12391,6 +12496,15 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
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c = 0x100 + '>'; /* flag &> */
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pungetc();
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}
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#endif
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#if BASH_PROCESS_SUBST
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if (c == '<' || c == '>') {
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if (pgetc() == '(') {
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PARSEPROCSUB();
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break;
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}
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pungetc();
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}
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#endif
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goto endword; /* exit outer loop */
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}
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@ -12876,9 +12990,18 @@ parsebackq: {
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memcpy(out, str, savelen);
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STADJUST(savelen, out);
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}
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#if BASH_PROCESS_SUBST
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if (style == PSUB)
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USTPUTC(c == '<' ? CTLFROMPROC : CTLTOPROC, out);
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else
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#endif
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USTPUTC(CTLBACKQ, out);
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if (oldstyle)
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goto parsebackq_oldreturn;
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#if BASH_PROCESS_SUBST
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else if (style == PSUB)
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goto parsebackq_psreturn;
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#endif
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goto parsebackq_newreturn;
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}
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@ -13329,6 +13452,9 @@ cmdloop(int top)
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#if JOBS
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if (doing_jobctl)
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showjobs(SHOW_CHANGED|SHOW_STDERR);
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#endif
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#if BASH_PROCESS_SUBST
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unwindredir(NULL);
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#endif
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inter = 0;
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if (iflag && top) {
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9
shell/ash_test/ash-psubst/bash_procsub.right
Normal file
9
shell/ash_test/ash-psubst/bash_procsub.right
Normal file
@ -0,0 +1,9 @@
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hello 1
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hello 2
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hello 3
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<(echo "hello 0")
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hello 4
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HI THERE
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hello error
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hello error
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hello stderr
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33
shell/ash_test/ash-psubst/bash_procsub.tests
Executable file
33
shell/ash_test/ash-psubst/bash_procsub.tests
Executable file
@ -0,0 +1,33 @@
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# simplest case
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cat <(echo "hello 1")
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# can have more than one
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cat <(echo "hello 2") <(echo "hello 3")
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# doesn't work in quotes
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echo "<(echo \"hello 0\")"
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# process substitution can be nested inside command substitution
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echo $(cat <(echo "hello 4"))
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# example from http://wiki.bash-hackers.org/syntax/expansion/proc_subst
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# process substitutions can be passed to a function as parameters or
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# variables
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f() {
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cat "$1" >"$x"
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}
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x=>(tr '[:lower:]' '[:upper:]') f <(echo 'hi there')
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# process substitution can be combined with redirection on exec
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rm -f err
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# save stderr
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exec 4>&2
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# copy stderr to a file
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exec 2> >(tee err)
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echo "hello error" >&2
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sync
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# restore stderr
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exec 2>&4
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cat err
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rm -f err
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echo "hello stderr" >&2
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