Add 'corebinutils/sh/' from commit '126b33a9db9b44a56f2c62d18346746ec1330766'

git-subtree-dir: corebinutils/sh
git-subtree-mainline: 96be0a182e0b889a9daf43c04a0b835aa604d280
git-subtree-split: 126b33a9db9b44a56f2c62d18346746ec1330766

1 files changed, 434 insertions, 0 deletions

diff --git a/corebinutils/sh/cd.c b/corebinutils/sh/cd.c
new file mode 100644
index 0000000000..4625186378
--- /dev/null
+++ b/corebinutils/sh/cd.c
@@ -0,0 +1,434 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2026 Project Tick. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <limits.h>
+
+/*
+ * The cd and pwd commands.
+ */
+
+#include "shell.h"
+#include "var.h"
+#include "nodes.h"	/* for jobs.h */
+#include "jobs.h"
+#include "options.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "exec.h"
+#include "redir.h"
+#include "mystring.h"
+#include "show.h"
+#include "cd.h"
+#include "builtins.h"
+
+static int cdlogical(char *);
+static int cdphysical(char *);
+static int docd(char *, int, int);
+static char *getcomponent(char **);
+static char *findcwd(char *);
+static void updatepwd(char *);
+static char *getpwd(void);
+static char *getpwd2(void);
+static char *getpwd_linux_procfs(void);
+
+static char *curdir = NULL;	/* current working directory */
+
+int
+cdcmd(int argc, char **argv)
+{
+	const char *dest;
+	const char *path;
+	char *p;
+	struct stat statb;
+	int ch, phys, print = 0, getcwderr = 0;
+	int rc;
+	int errno1 = ENOENT;
+
+	phys = Pflag;
+	while ((ch = nextopt("eLP")) != '\0') {
+		switch (ch) {
+		case 'e':
+			getcwderr = 1;
+			break;
+		case 'L':
+			phys = 0;
+			break;
+		case 'P':
+			phys = 1;
+			break;
+		}
+	}
+
+	if (*argptr != NULL && argptr[1] != NULL)
+		error("too many arguments");
+
+	if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
+		error("HOME not set");
+	if (dest[0] == '-' && dest[1] == '\0') {
+		dest = bltinlookup("OLDPWD", 1);
+		if (dest == NULL)
+			error("OLDPWD not set");
+		print = 1;
+	}
+	if (dest[0] == '/' ||
+	    (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
+	    (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
+	    (path = bltinlookup("CDPATH", 1)) == NULL)
+		path = "";
+	while ((p = padvance(&path, NULL, dest)) != NULL) {
+		if (stat(p, &statb) < 0) {
+			if (errno != ENOENT)
+				errno1 = errno;
+		} else if (!S_ISDIR(statb.st_mode))
+			errno1 = ENOTDIR;
+		else {
+			if (!print) {
+				/*
+				 * XXX - rethink
+				 */
+				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
+					print = strcmp(p + 2, dest);
+				else
+					print = strcmp(p, dest);
+			}
+			rc = docd(p, print, phys);
+			if (rc >= 0)
+				return getcwderr ? rc : 0;
+			if (errno != ENOENT)
+				errno1 = errno;
+		}
+	}
+	error("%s: %s", dest, strerror(errno1));
+	/*NOTREACHED*/
+	return 0;
+}
+
+
+/*
+ * Actually change the directory.  In an interactive shell, print the
+ * directory name if "print" is nonzero.
+ */
+static int
+docd(char *dest, int print, int phys)
+{
+	int rc;
+
+	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
+
+	/* If logical cd fails, fall back to physical. */
+	if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
+		return (-1);
+
+	if (print && iflag && curdir) {
+		out1fmt("%s\n", curdir);
+		/*
+		 * Ignore write errors to preserve the invariant that the
+		 * current directory is changed iff the exit status is 0
+		 * (or 1 if -e was given and the full pathname could not be
+		 * determined).
+		 */
+		flushout(out1);
+		outclearerror(out1);
+	}
+
+	return (rc);
+}
+
+static int
+cdlogical(char *dest)
+{
+	char *p;
+
+	INTOFF;
+	if (chdir(dest) < 0) {
+		INTON;
+		return (-1);
+	}
+	p = findcwd(dest);
+	if (p == NULL) {
+		INTON;
+		return (-1);
+	}
+	updatepwd(p);
+	INTON;
+	return (0);
+}
+
+static int
+cdphysical(char *dest)
+{
+	char *p;
+	int rc = 0;
+
+	INTOFF;
+	if (chdir(dest) < 0) {
+		INTON;
+		return (-1);
+	}
+	p = findcwd(NULL);
+	if (p == NULL) {
+		warning("warning: failed to get name of current directory");
+		rc = 1;
+	}
+	updatepwd(p);
+	INTON;
+	return (rc);
+}
+
+/*
+ * Get the next component of the path name pointed to by *path.
+ * This routine overwrites *path and the string pointed to by it.
+ */
+static char *
+getcomponent(char **path)
+{
+	char *p;
+	char *start;
+
+	if ((p = *path) == NULL)
+		return NULL;
+	start = *path;
+	while (*p != '/' && *p != '\0')
+		p++;
+	if (*p == '\0') {
+		*path = NULL;
+	} else {
+		*p++ = '\0';
+		*path = p;
+	}
+	return start;
+}
+
+
+static char *
+findcwd(char *dir)
+{
+	char *new;
+	char *p;
+	char *path;
+
+	/*
+	 * If our argument is NULL, we don't know the current directory
+	 * any more because we traversed a symbolic link or something
+	 * we couldn't stat().
+	 */
+	if (dir == NULL || curdir == NULL)
+		return getpwd2();
+	path = stsavestr(dir);
+	STARTSTACKSTR(new);
+	if (*dir != '/') {
+		STPUTS(curdir, new);
+		if (STTOPC(new) == '/')
+			STUNPUTC(new);
+	}
+	while ((p = getcomponent(&path)) != NULL) {
+		if (equal(p, "..")) {
+			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
+		} else if (*p != '\0' && ! equal(p, ".")) {
+			STPUTC('/', new);
+			STPUTS(p, new);
+		}
+	}
+	if (new == stackblock())
+		STPUTC('/', new);
+	STACKSTRNUL(new);
+	return stackblock();
+}
+
+/*
+ * Update curdir (the name of the current directory) in response to a
+ * cd command.  We also call hashcd to let the routines in exec.c know
+ * that the current directory has changed.
+ */
+static void
+updatepwd(char *dir)
+{
+	char *prevdir;
+
+	hashcd();				/* update command hash table */
+
+	setvar("PWD", dir, VEXPORT);
+	setvar("OLDPWD", curdir, VEXPORT);
+	prevdir = curdir;
+	curdir = dir ? savestr(dir) : NULL;
+	ckfree(prevdir);
+}
+
+int
+pwdcmd(int argc, char **argv)
+{
+	char *p;
+	int ch, phys;
+
+	phys = Pflag;
+	while ((ch = nextopt("LP")) != '\0') {
+		switch (ch) {
+		case 'L':
+			phys = 0;
+			break;
+		case 'P':
+			phys = 1;
+			break;
+		}
+	}
+
+	if (*argptr != NULL)
+		error("too many arguments");
+
+	if (!phys && getpwd()) {
+		out1str(curdir);
+		out1c('\n');
+	} else {
+		if ((p = getpwd2()) == NULL)
+			error(".: %s", strerror(errno));
+		out1str(p);
+		out1c('\n');
+	}
+
+	return 0;
+}
+
+/*
+ * Get the current directory and cache the result in curdir.
+ */
+static char *
+getpwd(void)
+{
+	char *p;
+
+	if (curdir)
+		return curdir;
+
+	p = getpwd2();
+	if (p != NULL) {
+		INTOFF;
+		curdir = savestr(p);
+		INTON;
+	}
+
+	return curdir;
+}
+
+#define MAXPWD 256
+
+static char *
+getpwd_linux_procfs(void)
+{
+#ifdef __linux__
+	char *pwd;
+	int i;
+	ssize_t length;
+
+	for (i = MAXPWD;; i *= 2) {
+		pwd = stalloc(i);
+		length = readlink("/proc/self/cwd", pwd, i - 1);
+		if (length >= 0) {
+			if (length < i - 1) {
+				pwd[length] = '\0';
+				return pwd;
+			}
+		} else if (errno != ENAMETOOLONG) {
+			stunalloc(pwd);
+			return NULL;
+		}
+		stunalloc(pwd);
+		if (i > INT_MAX / 2) {
+			errno = ENAMETOOLONG;
+			return NULL;
+		}
+	}
+#else
+	errno = ENOSYS;
+	return NULL;
+#endif
+}
+
+/*
+ * Return the current directory.
+ */
+static char *
+getpwd2(void)
+{
+	char *pwd;
+	int saved_errno;
+	int i;
+
+	for (i = MAXPWD;; i *= 2) {
+		pwd = stalloc(i);
+		if (getcwd(pwd, i) != NULL)
+			return pwd;
+		stunalloc(pwd);
+		if (errno != ERANGE)
+			break;
+	}
+
+	saved_errno = errno;
+	pwd = getpwd_linux_procfs();
+	if (pwd != NULL)
+		return pwd;
+	errno = saved_errno;
+	return NULL;
+}
+
+/*
+ * Initialize PWD in a new shell.
+ * If the shell is interactive, we need to warn if this fails.
+ */
+void
+pwd_init(int warn)
+{
+	char *pwd;
+	struct stat stdot, stpwd;
+
+	pwd = lookupvar("PWD");
+	if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
+	    stat(pwd, &stpwd) != -1 &&
+	    stdot.st_dev == stpwd.st_dev &&
+	    stdot.st_ino == stpwd.st_ino) {
+		if (curdir)
+			ckfree(curdir);
+		curdir = savestr(pwd);
+	}
+	if (getpwd() == NULL && warn)
+		out2fmt_flush("sh: cannot determine working directory\n");
+	setvar("PWD", curdir, VEXPORT);
+}