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a1b0d3856

Ron Yorston

2021-06-05

SUCCESS Duration: 154s

Subject

ash: add process substitution in bash-compatibility mode

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

include/platform.h +2 -0 shell/ash.c +143 -17 shell/ash_test/ash-psubst/bash_procsub.right +9 -0 shell/ash_test/ash-psubst/bash_procsub.tests +33 -0

include/platform.h+2 -0

@@ -426,6 +426,8 @@ typedef unsigned smalluint;
	#define HAVE_SYS_STATFS_H 1
	#define HAVE_PRINTF_PERCENTM 1
	#define HAVE_WAIT3 1
+	#define HAVE_DEV_FD 1
+	#define DEV_FD_PREFIX "/dev/fd/"

	#if defined(__UCLIBC__)
	# if UCLIBC_VERSION < KERNEL_VERSION(0, 9, 32)

shell/ash.c+143 -17

@@ -229,6 +229,14 @@
	#define BASH_READ_D ENABLE_ASH_BASH_COMPAT
	#define IF_BASH_READ_D IF_ASH_BASH_COMPAT
	#define BASH_WAIT_N ENABLE_ASH_BASH_COMPAT
+	/* <(...) and >(...) */
+	#if HAVE_DEV_FD
+	# define BASH_PROCESS_SUBST ENABLE_ASH_BASH_COMPAT
+	# define IF_BASH_PROCESS_SUBST IF_ASH_BASH_COMPAT
+	#else
+	# define BASH_PROCESS_SUBST 0
+	# define IF_BASH_PROCESS_SUBST(...)
+	#endif

	#if defined(__ANDROID_API__) && __ANDROID_API__ <= 24
	/* Bionic at least up to version 24 has no glob() */
@@ -804,6 +812,12 @@ out2str(const char *p)
	#define CTLENDARI ((unsigned char)'\207')
	#define CTLQUOTEMARK ((unsigned char)'\210')
	#define CTL_LAST CTLQUOTEMARK
+	#if BASH_PROCESS_SUBST
+	# define CTLTOPROC ((unsigned char)'\211')
+	# define CTLFROMPROC ((unsigned char)'\212')
+	# undef CTL_LAST
+	# define CTL_LAST CTLFROMPROC
+	#endif

	/* variable substitution byte (follows CTLVAR) */
	#define VSTYPE 0x0f /* type of variable substitution */
@@ -1075,6 +1089,10 @@ trace_puts_quoted(char *s)
	case CTLESC: c = 'e'; goto backslash;
	case CTLVAR: c = 'v'; goto backslash;
	case CTLBACKQ: c = 'q'; goto backslash;
+	#if BASH_PROCESS_SUBST
+	case CTLTOPROC: c = 'p'; goto backslash;
+	case CTLFROMPROC: c = 'P'; goto backslash;
+	#endif
	backslash:
	putc('\\', tracefile);
	putc(c, tracefile);
@@ -1236,8 +1254,17 @@ sharg(union node arg, FILE fp)
	case CTLENDVAR:
	putc('}', fp);
	break;
+	#if BASH_PROCESS_SUBST
+	case CTLTOPROC:
+	putc('>', fp);
+	goto backq;
+	case CTLFROMPROC:
+	putc('<', fp);
+	goto backq;
+	#endif
	case CTLBACKQ:
	putc('$', fp);
+	IF_BASH_PROCESS_SUBST(backq:)
	putc('(', fp);
	shtree(bqlist->n, -1, NULL, fp);
	putc(')', fp);
@@ -3234,8 +3261,13 @@ static const uint8_t syntax_index_table[] ALIGN1 = {
	/* 134 CTLARI */ CCTL_CCTL_CCTL_CCTL,
	/* 135 CTLENDARI */ CCTL_CCTL_CCTL_CCTL,
	/* 136 CTLQUOTEMARK */ CCTL_CCTL_CCTL_CCTL,
+	#if BASH_PROCESS_SUBST
+	/* 137 CTLTOPROC */ CCTL_CCTL_CCTL_CCTL,
+	/* 138 CTLFROMPROC */ CCTL_CCTL_CCTL_CCTL,
+	#else
	/* 137 */ CWORD_CWORD_CWORD_CWORD,
	/* 138 */ CWORD_CWORD_CWORD_CWORD,
+	#endif
	/* 139 */ CWORD_CWORD_CWORD_CWORD,
	/* 140 */ CWORD_CWORD_CWORD_CWORD,
	/* 141 */ CWORD_CWORD_CWORD_CWORD,
@@ -4849,9 +4881,24 @@ cmdputs(const char *s)
	quoted >>= 1;
	subtype = 0;
	goto dostr;
+	#if BASH_PROCESS_SUBST
+	case CTLBACKQ:
+	c = '$';
+	str = "(...)";
+	break;
+	case CTLTOPROC:
+	c = '>';
+	str = "(...)";
+	break;
+	case CTLFROMPROC:
+	c = '<';
+	str = "(...)";
+	break;
+	#else
	case CTLBACKQ:
	str = "$(...)";
	goto dostr;
+	#endif
	#if ENABLE_FEATURE_SH_MATH
	case CTLARI:
	str = "$((";
@@ -5891,6 +5938,21 @@ redirectsafe(union node *redir, int flags)
	return err;
	}

+	#if BASH_PROCESS_SUBST
+	static void
+	pushfd(int fd)
+	{
+	struct redirtab *sv;
+
+	sv = ckzalloc(sizeof(*sv) + sizeof(sv->two_fd[0]));
+	sv->pair_count = 1;
+	sv->two_fd[0].orig_fd = fd;
+	sv->two_fd[0].moved_to = CLOSED;
+	sv->next = redirlist;
+	redirlist = sv;
+	}
+	#endif
+
	static struct redirtab*
	pushredir(union node *redir)
	{
@@ -6529,10 +6591,20 @@ evaltreenr(union node *n, int flags)
	}

	static void FAST_FUNC
-	evalbackcmd(union node n, struct backcmd result)
+	evalbackcmd(union node n, struct backcmd result
+	IF_BASH_PROCESS_SUBST(, int ctl))
	{
	int pip[2];
	struct job *jp;
+	#if BASH_PROCESS_SUBST
+	/* determine end of pipe used by parent (ip) and child (ic) */
+	const int ip = (ctl == CTLTOPROC);
+	const int ic = !(ctl == CTLTOPROC);
+	#else
+	const int ctl = CTLBACKQ;
+	const int ip = 0;
+	const int ic = 1;
+	#endif

	result->fd = -1;
	result->buf = NULL;
@@ -6544,15 +6616,17 @@ evalbackcmd(union node n, struct backcmd result)

	if (pipe(pip) < 0)
	ash_msg_and_raise_perror("can't create pipe");
-	jp = makejob(/n,/ 1);
-	if (forkshell(jp, n, FORK_NOJOB) == 0) {
+	/* process substitution uses NULL job/node, like openhere() */
+	jp = (ctl == CTLBACKQ) ? makejob(/n,/ 1) : NULL;
+	if (forkshell(jp, (ctl == CTLBACKQ) ? n : NULL, FORK_NOJOB) == 0) {
	/* child */
	FORCE_INT_ON;
-	close(pip[0]);
-	if (pip[1] != 1) {
-	/close(1);/
-	dup2_or_raise(pip[1], 1);
-	close(pip[1]);
+	close(pip[ip]);
+	/* ic is index of child end of pipe and fd to connect it to */
+	if (pip[ic] != ic) {
+	/close(ic);/
+	dup2_or_raise(pip[ic], ic);
+	close(pip[ic]);
	}
	/* TODO: eflag clearing makes the following not abort:
	* ash -c 'set -e; z=$(false;echo foo); echo $z'
@@ -6568,8 +6642,18 @@ evalbackcmd(union node n, struct backcmd result)
	/* NOTREACHED */
	}
	/* parent */
-	close(pip[1]);
-	result->fd = pip[0];
+	#if BASH_PROCESS_SUBST
+	if (ctl != CTLBACKQ) {
+	int fd = fcntl(pip[ip], F_DUPFD, 64);
+	if (fd > 0) {
+	close(pip[ip]);
+	pip[ip] = fd;
+	}
+	pushfd(pip[ip]);
+	}
+	#endif
+	close(pip[ic]);
+	result->fd = pip[ip];
	result->jp = jp;

	out:
@@ -6581,8 +6665,11 @@ evalbackcmd(union node n, struct backcmd result)
	* Expand stuff in backwards quotes.
	*/
	static void
-	expbackq(union node *cmd, int flag)
+	expbackq(union node *cmd, int flag IF_BASH_PROCESS_SUBST(, int ctl))
	{
+	#if !BASH_PROCESS_SUBST
+	const int ctl = CTLBACKQ;
+	#endif
	struct backcmd in;
	int i;
	char buf[128];
@@ -6597,9 +6684,15 @@ expbackq(union node *cmd, int flag)
	INT_OFF;
	startloc = expdest - (char *)stackblock();
	pushstackmark(&smark, startloc);
-	evalbackcmd(cmd, &in);
+	evalbackcmd(cmd, &in IF_BASH_PROCESS_SUBST(, ctl));
	popstackmark(&smark);

+	if (ctl != CTLBACKQ) {
+	sprintf(buf, DEV_FD_PREFIX"%d", in.fd);
+	strtodest(buf, BASESYNTAX);
+	goto done;
+	}
+
	p = in.buf;
	i = in.nleft;
	if (i == 0)
@@ -6621,6 +6714,7 @@ expbackq(union node *cmd, int flag)
	close(in.fd);
	back_exitstatus = waitforjob(in.jp);
	}
+	done:
	INT_ON;

	/* Eat all trailing newlines */
@@ -6708,6 +6802,10 @@ argstr(char *p, int flag)
	CTLESC,
	CTLVAR,
	CTLBACKQ,
+	#if BASH_PROCESS_SUBST
+	CTLTOPROC,
+	CTLFROMPROC,
+	#endif
	#if ENABLE_FEATURE_SH_MATH
	CTLARI,
	CTLENDARI,
@@ -6807,8 +6905,12 @@ argstr(char *p, int flag)
	p = evalvar(p, flag \| inquotes);
	TRACE(("argstr: evalvar:'%s'\n", (char *)stackblock()));
	goto start;
+	#if BASH_PROCESS_SUBST
+	case CTLTOPROC:
+	case CTLFROMPROC:
+	#endif
	case CTLBACKQ:
-	expbackq(argbackq->n, flag \| inquotes);
+	expbackq(argbackq->n, flag \| inquotes IF_BASH_PROCESS_SUBST(, c));
	goto start;
	#if ENABLE_FEATURE_SH_MATH
	case CTLARI:
@@ -12198,8 +12300,9 @@ realeofmark(const char *eofmark)
	#define CHECKEND() {goto checkend; checkend_return:;}
	#define PARSEREDIR() {goto parseredir; parseredir_return:;}
	#define PARSESUB() {goto parsesub; parsesub_return:;}
-	#define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
-	#define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
+	#define PARSEBACKQOLD() {style = OLD; goto parsebackq; parsebackq_oldreturn:;}
+	#define PARSEBACKQNEW() {style = NEW; goto parsebackq; parsebackq_newreturn:;}
+	#define PARSEPROCSUB() {style = PSUB; goto parsebackq; parsebackq_psreturn:;}
	#define PARSEARITH() {goto parsearith; parsearith_return:;}
	static int
	readtoken1(int c, int syntax, char *eofmark, int striptabs)
@@ -12210,7 +12313,9 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
	size_t len;
	struct nodelist *bqlist;
	smallint quotef;
-	smallint oldstyle;
+	smallint style;
+	enum { OLD, NEW, PSUB };
+	#define oldstyle (style == OLD)
	smallint pssyntax; /* we are expanding a prompt string */
	IF_BASH_DOLLAR_SQUOTE(smallint bash_dollar_squote = 0;)
	/* syntax stack */
@@ -12391,6 +12496,15 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
	c = 0x100 + '>'; /* flag &> */
	pungetc();
	}
+	#endif
+	#if BASH_PROCESS_SUBST
+	if (c == '<' \|\| c == '>') {
+	if (pgetc() == '(') {
+	PARSEPROCSUB();
+	break;
+	}
+	pungetc();
+	}
	#endif
	goto endword; /* exit outer loop */
	}
@@ -12876,9 +12990,18 @@ parsebackq: {
	memcpy(out, str, savelen);
	STADJUST(savelen, out);
	}
-	USTPUTC(CTLBACKQ, out);
+	#if BASH_PROCESS_SUBST
+	if (style == PSUB)
+	USTPUTC(c == '<' ? CTLFROMPROC : CTLTOPROC, out);
+	else
+	#endif
+	USTPUTC(CTLBACKQ, out);
	if (oldstyle)
	goto parsebackq_oldreturn;
+	#if BASH_PROCESS_SUBST
+	else if (style == PSUB)
+	goto parsebackq_psreturn;
+	#endif
	goto parsebackq_newreturn;
	}

@@ -13329,6 +13452,9 @@ cmdloop(int top)
	#if JOBS
	if (doing_jobctl)
	showjobs(SHOW_CHANGED\|SHOW_STDERR);
+	#endif
+	#if BASH_PROCESS_SUBST
+	unwindredir(NULL);
	#endif
	inter = 0;
	if (iflag && top) {

shell/ash_test/ash-psubst/bash_procsub.right+9 -0

@@ -0,0 +1,9 @@
+	hello 1
+	hello 2
+	hello 3
+	<(echo "hello 0")
+	hello 4
+	HI THERE
+	hello error
+	hello error
+	hello stderr

shell/ash_test/ash-psubst/bash_procsub.tests+33 -0

@@ -0,0 +1,33 @@
+	# simplest case
+	cat <(echo "hello 1")
+
+	# can have more than one
+	cat <(echo "hello 2") <(echo "hello 3")
+
+	# doesn't work in quotes
+	echo "<(echo \"hello 0\")"
+
+	# process substitution can be nested inside command substitution
+	echo $(cat <(echo "hello 4"))
+
+	# example from http://wiki.bash-hackers.org/syntax/expansion/proc_subst
+	# process substitutions can be passed to a function as parameters or
+	# variables
+	f() {
+	cat "$1" >"$x"
+	}
+	x=>(tr '[:lower:]' '[:upper:]') f <(echo 'hi there')
+
+	# process substitution can be combined with redirection on exec
+	rm -f err
+	# save stderr
+	exec 4>&2
+	# copy stderr to a file
+	exec 2> >(tee err)
+	echo "hello error" >&2
+	sync
+	# restore stderr
+	exec 2>&4
+	cat err
+	rm -f err
+	echo "hello stderr" >&2