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-rw-r--r--bin/1sh/exec.c784
1 files changed, 784 insertions, 0 deletions
diff --git a/bin/1sh/exec.c b/bin/1sh/exec.c
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index 00000000..5026e644
--- /dev/null
+++ b/bin/1sh/exec.c
@@ -0,0 +1,784 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  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.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)exec.c	8.4 (Berkeley) 6/8/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: releng/12.0/bin/sh/exec.c 336320 2018-07-15 21:55:17Z jilles $");
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <paths.h>
+#include <stdlib.h>
+
+/*
+ * When commands are first encountered, they are entered in a hash table.
+ * This ensures that a full path search will not have to be done for them
+ * on each invocation.
+ *
+ * We should investigate converting to a linear search, even though that
+ * would make the command name "hash" a misnomer.
+ */
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"
+#include "parser.h"
+#include "redir.h"
+#include "eval.h"
+#include "exec.h"
+#include "builtins.h"
+#include "var.h"
+#include "options.h"
+#include "input.h"
+#include "output.h"
+#include "syntax.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "show.h"
+#include "jobs.h"
+#include "alias.h"
+
+
+#define CMDTABLESIZE 31		/* should be prime */
+
+
+
+struct tblentry {
+	struct tblentry *next;	/* next entry in hash chain */
+	union param param;	/* definition of builtin function */
+	int special;		/* flag for special builtin commands */
+	signed char cmdtype;	/* index identifying command */
+	char cmdname[];		/* name of command */
+};
+
+
+static struct tblentry *cmdtable[CMDTABLESIZE];
+static int cmdtable_cd = 0;	/* cmdtable contains cd-dependent entries */
+int exerrno = 0;			/* Last exec error */
+
+
+static void tryexec(char *, char **, char **);
+static void printentry(struct tblentry *, int);
+static struct tblentry *cmdlookup(const char *, int);
+static void delete_cmd_entry(void);
+static void addcmdentry(const char *, struct cmdentry *);
+
+
+
+/*
+ * Exec a program.  Never returns.  If you change this routine, you may
+ * have to change the find_command routine as well.
+ *
+ * The argv array may be changed and element argv[-1] should be writable.
+ */
+
+void
+shellexec(char **argv, char **envp, const char *path, int idx)
+{
+	char *cmdname;
+	const char *opt;
+	int e;
+
+	if (strchr(argv[0], '/') != NULL) {
+		tryexec(argv[0], argv, envp);
+		e = errno;
+	} else {
+		e = ENOENT;
+		while ((cmdname = padvance(&path, &opt, argv[0])) != NULL) {
+			if (--idx < 0 && opt == NULL) {
+				tryexec(cmdname, argv, envp);
+				if (errno != ENOENT && errno != ENOTDIR)
+					e = errno;
+				if (e == ENOEXEC)
+					break;
+			}
+			stunalloc(cmdname);
+		}
+	}
+
+	/* Map to POSIX errors */
+	if (e == ENOENT || e == ENOTDIR) {
+		exerrno = 127;
+		exerror(EXEXEC, "%s: not found", argv[0]);
+	} else {
+		exerrno = 126;
+		exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
+	}
+}
+
+
+static void
+tryexec(char *cmd, char **argv, char **envp)
+{
+	int e, in;
+	ssize_t n;
+	char buf[256];
+
+	execve(cmd, argv, envp);
+	e = errno;
+	if (e == ENOEXEC) {
+		INTOFF;
+		in = open(cmd, O_RDONLY | O_NONBLOCK);
+		if (in != -1) {
+			n = pread(in, buf, sizeof buf, 0);
+			close(in);
+			if (n > 0 && memchr(buf, '\0', n) != NULL) {
+				errno = ENOEXEC;
+				return;
+			}
+		}
+		*argv = cmd;
+		*--argv = __DECONST(char *, _PATH_BSHELL);
+		execve(_PATH_BSHELL, argv, envp);
+	}
+	errno = e;
+}
+
+/*
+ * Do a path search.  The variable path (passed by reference) should be
+ * set to the start of the path before the first call; padvance will update
+ * this value as it proceeds.  Successive calls to padvance will return
+ * the possible path expansions in sequence.  If popt is not NULL, options
+ * are processed: if an option (indicated by a percent sign) appears in
+ * the path entry then *popt will be set to point to it; else *popt will be
+ * set to NULL.  If popt is NULL, percent signs are not special.
+ */
+
+char *
+padvance(const char **path, const char **popt, const char *name)
+{
+	const char *p, *start;
+	char *q;
+	size_t len, namelen;
+
+	if (*path == NULL)
+		return NULL;
+	start = *path;
+	if (popt != NULL)
+		for (p = start; *p && *p != ':' && *p != '%'; p++)
+			; /* nothing */
+	else
+		for (p = start; *p && *p != ':'; p++)
+			; /* nothing */
+	namelen = strlen(name);
+	len = p - start + namelen + 2;	/* "2" is for '/' and '\0' */
+	STARTSTACKSTR(q);
+	CHECKSTRSPACE(len, q);
+	if (p != start) {
+		memcpy(q, start, p - start);
+		q += p - start;
+		*q++ = '/';
+	}
+	memcpy(q, name, namelen + 1);
+	if (popt != NULL) {
+		if (*p == '%') {
+			*popt = ++p;
+			while (*p && *p != ':')  p++;
+		} else
+			*popt = NULL;
+	}
+	if (*p == ':')
+		*path = p + 1;
+	else
+		*path = NULL;
+	return stalloc(len);
+}
+
+
+
+/*** Command hashing code ***/
+
+
+int
+hashcmd(int argc __unused, char **argv __unused)
+{
+	struct tblentry **pp;
+	struct tblentry *cmdp;
+	int c;
+	int verbose;
+	struct cmdentry entry;
+	char *name;
+	int errors;
+
+	errors = 0;
+	verbose = 0;
+	while ((c = nextopt("rv")) != '\0') {
+		if (c == 'r') {
+			clearcmdentry();
+		} else if (c == 'v') {
+			verbose++;
+		}
+	}
+	if (*argptr == NULL) {
+		for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
+			for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
+				if (cmdp->cmdtype == CMDNORMAL)
+					printentry(cmdp, verbose);
+			}
+		}
+		return 0;
+	}
+	while ((name = *argptr) != NULL) {
+		if ((cmdp = cmdlookup(name, 0)) != NULL
+		 && cmdp->cmdtype == CMDNORMAL)
+			delete_cmd_entry();
+		find_command(name, &entry, DO_ERR, pathval());
+		if (entry.cmdtype == CMDUNKNOWN)
+			errors = 1;
+		else if (verbose) {
+			cmdp = cmdlookup(name, 0);
+			if (cmdp != NULL)
+				printentry(cmdp, verbose);
+			else {
+				outfmt(out2, "%s: not found\n", name);
+				errors = 1;
+			}
+			flushall();
+		}
+		argptr++;
+	}
+	return errors;
+}
+
+
+static void
+printentry(struct tblentry *cmdp, int verbose)
+{
+	int idx;
+	const char *path, *opt;
+	char *name;
+
+	if (cmdp->cmdtype == CMDNORMAL) {
+		idx = cmdp->param.index;
+		path = pathval();
+		do {
+			name = padvance(&path, &opt, cmdp->cmdname);
+			stunalloc(name);
+		} while (--idx >= 0);
+		out1str(name);
+	} else if (cmdp->cmdtype == CMDBUILTIN) {
+		out1fmt("builtin %s", cmdp->cmdname);
+	} else if (cmdp->cmdtype == CMDFUNCTION) {
+		out1fmt("function %s", cmdp->cmdname);
+		if (verbose) {
+			INTOFF;
+			name = commandtext(getfuncnode(cmdp->param.func));
+			out1c(' ');
+			out1str(name);
+			ckfree(name);
+			INTON;
+		}
+#ifdef DEBUG
+	} else {
+		error("internal error: cmdtype %d", cmdp->cmdtype);
+#endif
+	}
+	out1c('\n');
+}
+
+
+
+/*
+ * Resolve a command name.  If you change this routine, you may have to
+ * change the shellexec routine as well.
+ */
+
+void
+find_command(const char *name, struct cmdentry *entry, int act,
+    const char *path)
+{
+	struct tblentry *cmdp, loc_cmd;
+	int idx;
+	const char *opt;
+	char *fullname;
+	struct stat statb;
+	int e;
+	int i;
+	int spec;
+	int cd;
+
+	/* If name contains a slash, don't use the hash table */
+	if (strchr(name, '/') != NULL) {
+		entry->cmdtype = CMDNORMAL;
+		entry->u.index = 0;
+		entry->special = 0;
+		return;
+	}
+
+	cd = 0;
+
+	/* If name is in the table, we're done */
+	if ((cmdp = cmdlookup(name, 0)) != NULL) {
+		if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
+			cmdp = NULL;
+		else
+			goto success;
+	}
+
+	/* Check for builtin next */
+	if ((i = find_builtin(name, &spec)) >= 0) {
+		INTOFF;
+		cmdp = cmdlookup(name, 1);
+		if (cmdp->cmdtype == CMDFUNCTION)
+			cmdp = &loc_cmd;
+		cmdp->cmdtype = CMDBUILTIN;
+		cmdp->param.index = i;
+		cmdp->special = spec;
+		INTON;
+		goto success;
+	}
+
+	/* We have to search path. */
+
+	e = ENOENT;
+	idx = -1;
+	for (;(fullname = padvance(&path, &opt, name)) != NULL;
+	    stunalloc(fullname)) {
+		idx++;
+		if (opt) {
+			if (strncmp(opt, "func", 4) == 0) {
+				/* handled below */
+			} else {
+				continue; /* ignore unimplemented options */
+			}
+		}
+		if (fullname[0] != '/')
+			cd = 1;
+		if (stat(fullname, &statb) < 0) {
+			if (errno != ENOENT && errno != ENOTDIR)
+				e = errno;
+			continue;
+		}
+		e = EACCES;	/* if we fail, this will be the error */
+		if (!S_ISREG(statb.st_mode))
+			continue;
+		if (opt) {		/* this is a %func directory */
+			readcmdfile(fullname);
+			if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
+				error("%s not defined in %s", name, fullname);
+			stunalloc(fullname);
+			goto success;
+		}
+#ifdef notdef
+		if (statb.st_uid == geteuid()) {
+			if ((statb.st_mode & 0100) == 0)
+				goto loop;
+		} else if (statb.st_gid == getegid()) {
+			if ((statb.st_mode & 010) == 0)
+				goto loop;
+		} else {
+			if ((statb.st_mode & 01) == 0)
+				goto loop;
+		}
+#endif
+		TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
+		INTOFF;
+		stunalloc(fullname);
+		cmdp = cmdlookup(name, 1);
+		if (cmdp->cmdtype == CMDFUNCTION)
+			cmdp = &loc_cmd;
+		cmdp->cmdtype = CMDNORMAL;
+		cmdp->param.index = idx;
+		cmdp->special = 0;
+		INTON;
+		goto success;
+	}
+
+	if (act & DO_ERR) {
+		if (e == ENOENT || e == ENOTDIR)
+			outfmt(out2, "%s: not found\n", name);
+		else
+			outfmt(out2, "%s: %s\n", name, strerror(e));
+	}
+	entry->cmdtype = CMDUNKNOWN;
+	entry->u.index = 0;
+	entry->special = 0;
+	return;
+
+success:
+	if (cd)
+		cmdtable_cd = 1;
+	entry->cmdtype = cmdp->cmdtype;
+	entry->u = cmdp->param;
+	entry->special = cmdp->special;
+}
+
+
+
+/*
+ * Search the table of builtin commands.
+ */
+
+int
+find_builtin(const char *name, int *special)
+{
+	const unsigned char *bp;
+	size_t len;
+
+	len = strlen(name);
+	for (bp = builtincmd ; *bp ; bp += 2 + bp[0]) {
+		if (bp[0] == len && memcmp(bp + 2, name, len) == 0) {
+			*special = (bp[1] & BUILTIN_SPECIAL) != 0;
+			return bp[1] & ~BUILTIN_SPECIAL;
+		}
+	}
+	return -1;
+}
+
+
+
+/*
+ * Called when a cd is done.  If any entry in cmdtable depends on the current
+ * directory, simply clear cmdtable completely.
+ */
+
+void
+hashcd(void)
+{
+	if (cmdtable_cd)
+		clearcmdentry();
+}
+
+
+
+/*
+ * Called before PATH is changed.  The argument is the new value of PATH;
+ * pathval() still returns the old value at this point.  Called with
+ * interrupts off.
+ */
+
+void
+changepath(const char *newval __unused)
+{
+	clearcmdentry();
+}
+
+
+/*
+ * Clear out cached utility locations.
+ */
+
+void
+clearcmdentry(void)
+{
+	struct tblentry **tblp;
+	struct tblentry **pp;
+	struct tblentry *cmdp;
+
+	INTOFF;
+	for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
+		pp = tblp;
+		while ((cmdp = *pp) != NULL) {
+			if (cmdp->cmdtype == CMDNORMAL) {
+				*pp = cmdp->next;
+				ckfree(cmdp);
+			} else {
+				pp = &cmdp->next;
+			}
+		}
+	}
+	cmdtable_cd = 0;
+	INTON;
+}
+
+
+/*
+ * Locate a command in the command hash table.  If "add" is nonzero,
+ * add the command to the table if it is not already present.  The
+ * variable "lastcmdentry" is set to point to the address of the link
+ * pointing to the entry, so that delete_cmd_entry can delete the
+ * entry.
+ */
+
+static struct tblentry **lastcmdentry;
+
+
+static struct tblentry *
+cmdlookup(const char *name, int add)
+{
+	unsigned int hashval;
+	const char *p;
+	struct tblentry *cmdp;
+	struct tblentry **pp;
+	size_t len;
+
+	p = name;
+	hashval = (unsigned char)*p << 4;
+	while (*p)
+		hashval += *p++;
+	pp = &cmdtable[hashval % CMDTABLESIZE];
+	for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
+		if (equal(cmdp->cmdname, name))
+			break;
+		pp = &cmdp->next;
+	}
+	if (add && cmdp == NULL) {
+		INTOFF;
+		len = strlen(name);
+		cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1);
+		cmdp->next = NULL;
+		cmdp->cmdtype = CMDUNKNOWN;
+		memcpy(cmdp->cmdname, name, len + 1);
+		INTON;
+	}
+	lastcmdentry = pp;
+	return cmdp;
+}
+
+/*
+ * Delete the command entry returned on the last lookup.
+ */
+
+static void
+delete_cmd_entry(void)
+{
+	struct tblentry *cmdp;
+
+	INTOFF;
+	cmdp = *lastcmdentry;
+	*lastcmdentry = cmdp->next;
+	ckfree(cmdp);
+	INTON;
+}
+
+
+
+/*
+ * Add a new command entry, replacing any existing command entry for
+ * the same name.
+ */
+
+static void
+addcmdentry(const char *name, struct cmdentry *entry)
+{
+	struct tblentry *cmdp;
+
+	INTOFF;
+	cmdp = cmdlookup(name, 1);
+	if (cmdp->cmdtype == CMDFUNCTION) {
+		unreffunc(cmdp->param.func);
+	}
+	cmdp->cmdtype = entry->cmdtype;
+	cmdp->param = entry->u;
+	cmdp->special = entry->special;
+	INTON;
+}
+
+
+/*
+ * Define a shell function.
+ */
+
+void
+defun(const char *name, union node *func)
+{
+	struct cmdentry entry;
+
+	INTOFF;
+	entry.cmdtype = CMDFUNCTION;
+	entry.u.func = copyfunc(func);
+	entry.special = 0;
+	addcmdentry(name, &entry);
+	INTON;
+}
+
+
+/*
+ * Delete a function if it exists.
+ * Called with interrupts off.
+ */
+
+int
+unsetfunc(const char *name)
+{
+	struct tblentry *cmdp;
+
+	if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
+		unreffunc(cmdp->param.func);
+		delete_cmd_entry();
+		return (0);
+	}
+	return (0);
+}
+
+
+/*
+ * Check if a function by a certain name exists.
+ */
+int
+isfunc(const char *name)
+{
+	struct tblentry *cmdp;
+	cmdp = cmdlookup(name, 0);
+	return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
+}
+
+
+/*
+ * Shared code for the following builtin commands:
+ *    type, command -v, command -V
+ */
+
+int
+typecmd_impl(int argc, char **argv, int cmd, const char *path)
+{
+	struct cmdentry entry;
+	struct tblentry *cmdp;
+	const char *const *pp;
+	struct alias *ap;
+	int i;
+	int error1 = 0;
+
+	if (path != pathval())
+		clearcmdentry();
+
+	for (i = 1; i < argc; i++) {
+		/* First look at the keywords */
+		for (pp = parsekwd; *pp; pp++)
+			if (**pp == *argv[i] && equal(*pp, argv[i]))
+				break;
+
+		if (*pp) {
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else
+				out1fmt("%s is a shell keyword\n", argv[i]);
+			continue;
+		}
+
+		/* Then look at the aliases */
+		if ((ap = lookupalias(argv[i], 1)) != NULL) {
+			if (cmd == TYPECMD_SMALLV) {
+				out1fmt("alias %s=", argv[i]);
+				out1qstr(ap->val);
+				outcslow('\n', out1);
+			} else
+				out1fmt("%s is an alias for %s\n", argv[i],
+				    ap->val);
+			continue;
+		}
+
+		/* Then check if it is a tracked alias */
+		if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
+			entry.cmdtype = cmdp->cmdtype;
+			entry.u = cmdp->param;
+			entry.special = cmdp->special;
+		}
+		else {
+			/* Finally use brute force */
+			find_command(argv[i], &entry, 0, path);
+		}
+
+		switch (entry.cmdtype) {
+		case CMDNORMAL: {
+			if (strchr(argv[i], '/') == NULL) {
+				const char *path2 = path;
+				const char *opt2;
+				char *name;
+				int j = entry.u.index;
+				do {
+					name = padvance(&path2, &opt2, argv[i]);
+					stunalloc(name);
+				} while (--j >= 0);
+				if (cmd == TYPECMD_SMALLV)
+					out1fmt("%s\n", name);
+				else
+					out1fmt("%s is%s %s\n", argv[i],
+					    (cmdp && cmd == TYPECMD_TYPE) ?
+						" a tracked alias for" : "",
+					    name);
+			} else {
+				if (faccessat(AT_FDCWD, argv[i], X_OK, AT_EACCESS) == 0) {
+					if (cmd == TYPECMD_SMALLV)
+						out1fmt("%s\n", argv[i]);
+					else
+						out1fmt("%s is %s\n", argv[i],
+						    argv[i]);
+				} else {
+					if (cmd != TYPECMD_SMALLV)
+						outfmt(out2, "%s: %s\n",
+						    argv[i], strerror(errno));
+					error1 |= 127;
+				}
+			}
+			break;
+		}
+		case CMDFUNCTION:
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else
+				out1fmt("%s is a shell function\n", argv[i]);
+			break;
+
+		case CMDBUILTIN:
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else if (entry.special)
+				out1fmt("%s is a special shell builtin\n",
+				    argv[i]);
+			else
+				out1fmt("%s is a shell builtin\n", argv[i]);
+			break;
+
+		default:
+			if (cmd != TYPECMD_SMALLV)
+				outfmt(out2, "%s: not found\n", argv[i]);
+			error1 |= 127;
+			break;
+		}
+	}
+
+	if (path != pathval())
+		clearcmdentry();
+
+	return error1;
+}
+
+/*
+ * Locate and print what a word is...
+ */
+
+int
+typecmd(int argc, char **argv)
+{
+	if (argc > 2 && strcmp(argv[1], "--") == 0)
+		argc--, argv++;
+	return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));
+}