freebsd-dev/bin/sh/exec.c
Stefan Farfeleder 85170a4a2a Implement some of the differences between special built-ins and other builtins
demanded by POSIX.
- A redirection error is only fatal (meaning the execution of a shell script is
  terminated) for special built-ins.  Previously it was fatal for all shell
  builtins, causing problems like the one reported in PR 88845.
- Variable assignments remain in effect for special built-ins.
- Option or operand errors are only fatal for special built-ins.
This change also makes errors from 'fc' non-fatal (I could not find any reasons
for this behaviour).

Somewhat independently from the above down-grade the error handling in the
shift built-in if the operand is bigger than $# from an error() call (which is
now fatal) to a return 1.  I'm not sure if this should be considered a POSIX
"operand error", however this change is needed for now as we trigger that error
while building libncurses.  Comparing with other shells, zsh does the same as
our sh before this change (write a diagnostic, return 1), bash behaves as our
sh after this commit (no diagnostic, return 1) and ksh93 and NetBSD's sh treat
it as a fatal error.
2006-04-09 12:21:20 +00:00

827 lines
17 KiB
C

/*-
* 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.
* 4. 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("$FreeBSD$");
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.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 "init.h"
#include "mystring.h"
#include "show.h"
#include "jobs.h"
#include "alias.h"
#define CMDTABLESIZE 31 /* should be prime */
#define ARB 1 /* actual size determined at run time */
struct tblentry {
struct tblentry *next; /* next entry in hash chain */
union param param; /* definition of builtin function */
int special; /* flag for special builtin commands */
short cmdtype; /* index identifying command */
char rehash; /* if set, cd done since entry created */
char cmdname[ARB]; /* name of command */
};
STATIC struct tblentry *cmdtable[CMDTABLESIZE];
STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */
int exerrno = 0; /* Last exec error */
STATIC void tryexec(char *, char **, char **);
STATIC void printentry(struct tblentry *, int);
STATIC struct tblentry *cmdlookup(char *, int);
STATIC void delete_cmd_entry(void);
/*
* Exec a program. Never returns. If you change this routine, you may
* have to change the find_command routine as well.
*/
void
shellexec(char **argv, char **envp, char *path, int index)
{
char *cmdname;
int e;
if (strchr(argv[0], '/') != NULL) {
tryexec(argv[0], argv, envp);
e = errno;
} else {
e = ENOENT;
while ((cmdname = padvance(&path, argv[0])) != NULL) {
if (--index < 0 && pathopt == NULL) {
tryexec(cmdname, argv, envp);
if (errno != ENOENT && errno != ENOTDIR)
e = errno;
}
stunalloc(cmdname);
}
}
/* Map to POSIX errors */
switch (e) {
case EACCES:
exerrno = 126;
break;
case ENOENT:
exerrno = 127;
break;
default:
exerrno = 2;
break;
}
if (e == ENOENT || e == ENOTDIR)
exerror(EXEXEC, "%s: not found", argv[0]);
exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
}
STATIC void
tryexec(char *cmd, char **argv, char **envp)
{
int e;
execve(cmd, argv, envp);
e = errno;
if (e == ENOEXEC) {
initshellproc();
setinputfile(cmd, 0);
commandname = arg0 = savestr(argv[0]);
setparam(argv + 1);
exraise(EXSHELLPROC);
/*NOTREACHED*/
}
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 an option (indicated by
* a percent sign) appears in the path entry then the global variable
* pathopt will be set to point to it; otherwise pathopt will be set to
* NULL.
*/
char *pathopt;
char *
padvance(char **path, char *name)
{
char *p, *q;
char *start;
int len;
if (*path == NULL)
return NULL;
start = *path;
for (p = start ; *p && *p != ':' && *p != '%' ; p++);
len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
while (stackblocksize() < len)
growstackblock();
q = stackblock();
if (p != start) {
memcpy(q, start, p - start);
q += p - start;
*q++ = '/';
}
strcpy(q, name);
pathopt = NULL;
if (*p == '%') {
pathopt = ++p;
while (*p && *p != ':') p++;
}
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;
verbose = 0;
while ((c = nextopt("rv")) != '\0') {
if (c == 'r') {
clearcmdentry(0);
} 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
|| (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)))
delete_cmd_entry();
find_command(name, &entry, 1, pathval());
if (verbose) {
if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
cmdp = cmdlookup(name, 0);
if (cmdp != NULL)
printentry(cmdp, verbose);
else
outfmt(&errout, "%s: not found\n", name);
}
flushall();
}
argptr++;
}
return 0;
}
STATIC void
printentry(struct tblentry *cmdp, int verbose)
{
int index;
char *path;
char *name;
if (cmdp->cmdtype == CMDNORMAL) {
index = cmdp->param.index;
path = pathval();
do {
name = padvance(&path, cmdp->cmdname);
stunalloc(name);
} while (--index >= 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(cmdp->param.func);
out1c(' ');
out1str(name);
ckfree(name);
INTON;
}
#ifdef DEBUG
} else {
error("internal error: cmdtype %d", cmdp->cmdtype);
#endif
}
if (cmdp->rehash)
out1c('*');
out1c('\n');
}
/*
* Resolve a command name. If you change this routine, you may have to
* change the shellexec routine as well.
*/
void
find_command(char *name, struct cmdentry *entry, int printerr, char *path)
{
struct tblentry *cmdp;
int index;
int prev;
char *fullname;
struct stat statb;
int e;
int i;
int spec;
/* If name contains a slash, don't use the hash table */
if (strchr(name, '/') != NULL) {
entry->cmdtype = CMDNORMAL;
entry->u.index = 0;
return;
}
/* If name is in the table, and not invalidated by cd, we're done */
if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0)
goto success;
/* If %builtin not in path, check for builtin next */
if (builtinloc < 0 && (i = find_builtin(name, &spec)) >= 0) {
INTOFF;
cmdp = cmdlookup(name, 1);
cmdp->cmdtype = CMDBUILTIN;
cmdp->param.index = i;
cmdp->special = spec;
INTON;
goto success;
}
/* We have to search path. */
prev = -1; /* where to start */
if (cmdp) { /* doing a rehash */
if (cmdp->cmdtype == CMDBUILTIN)
prev = builtinloc;
else
prev = cmdp->param.index;
}
e = ENOENT;
index = -1;
loop:
while ((fullname = padvance(&path, name)) != NULL) {
stunalloc(fullname);
index++;
if (pathopt) {
if (prefix("builtin", pathopt)) {
if ((i = find_builtin(name, &spec)) < 0)
goto loop;
INTOFF;
cmdp = cmdlookup(name, 1);
cmdp->cmdtype = CMDBUILTIN;
cmdp->param.index = i;
cmdp->special = spec;
INTON;
goto success;
} else if (prefix("func", pathopt)) {
/* handled below */
} else {
goto loop; /* ignore unimplemented options */
}
}
/* if rehash, don't redo absolute path names */
if (fullname[0] == '/' && index <= prev) {
if (index < prev)
goto loop;
TRACE(("searchexec \"%s\": no change\n", name));
goto success;
}
if (stat(fullname, &statb) < 0) {
if (errno != ENOENT && errno != ENOTDIR)
e = errno;
goto loop;
}
e = EACCES; /* if we fail, this will be the error */
if (!S_ISREG(statb.st_mode))
goto loop;
if (pathopt) { /* this is a %func directory */
stalloc(strlen(fullname) + 1);
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;
cmdp = cmdlookup(name, 1);
cmdp->cmdtype = CMDNORMAL;
cmdp->param.index = index;
INTON;
goto success;
}
/* We failed. If there was an entry for this command, delete it */
if (cmdp)
delete_cmd_entry();
if (printerr) {
if (e == ENOENT || e == ENOTDIR)
outfmt(out2, "%s: not found\n", name);
else
outfmt(out2, "%s: %s\n", name, strerror(e));
}
entry->cmdtype = CMDUNKNOWN;
return;
success:
cmdp->rehash = 0;
entry->cmdtype = cmdp->cmdtype;
entry->u = cmdp->param;
entry->special = cmdp->special;
}
/*
* Search the table of builtin commands.
*/
int
find_builtin(char *name, int *special)
{
const struct builtincmd *bp;
for (bp = builtincmd ; bp->name ; bp++) {
if (*bp->name == *name && equal(bp->name, name)) {
*special = bp->special;
return bp->code;
}
}
return -1;
}
/*
* Called when a cd is done. Marks all commands so the next time they
* are executed they will be rehashed.
*/
void
hashcd(void)
{
struct tblentry **pp;
struct tblentry *cmdp;
for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
if (cmdp->cmdtype == CMDNORMAL
|| (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
cmdp->rehash = 1;
}
}
}
/*
* 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)
{
const char *old, *new;
int index;
int firstchange;
int bltin;
old = pathval();
new = newval;
firstchange = 9999; /* assume no change */
index = 0;
bltin = -1;
for (;;) {
if (*old != *new) {
firstchange = index;
if ((*old == '\0' && *new == ':')
|| (*old == ':' && *new == '\0'))
firstchange++;
old = new; /* ignore subsequent differences */
}
if (*new == '\0')
break;
if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
bltin = index;
if (*new == ':') {
index++;
}
new++, old++;
}
if (builtinloc < 0 && bltin >= 0)
builtinloc = bltin; /* zap builtins */
if (builtinloc >= 0 && bltin < 0)
firstchange = 0;
clearcmdentry(firstchange);
builtinloc = bltin;
}
/*
* Clear out command entries. The argument specifies the first entry in
* PATH which has changed.
*/
void
clearcmdentry(int firstchange)
{
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 &&
cmdp->param.index >= firstchange)
|| (cmdp->cmdtype == CMDBUILTIN &&
builtinloc >= firstchange)) {
*pp = cmdp->next;
ckfree(cmdp);
} else {
pp = &cmdp->next;
}
}
}
INTON;
}
/*
* Delete all functions.
*/
#ifdef mkinit
MKINIT void deletefuncs(void);
SHELLPROC {
deletefuncs();
}
#endif
void
deletefuncs(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 == CMDFUNCTION) {
*pp = cmdp->next;
freefunc(cmdp->param.func);
ckfree(cmdp);
} else {
pp = &cmdp->next;
}
}
}
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(char *name, int add)
{
int hashval;
char *p;
struct tblentry *cmdp;
struct tblentry **pp;
p = name;
hashval = *p << 4;
while (*p)
hashval += *p++;
hashval &= 0x7FFF;
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;
cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
+ strlen(name) + 1);
cmdp->next = NULL;
cmdp->cmdtype = CMDUNKNOWN;
cmdp->rehash = 0;
strcpy(cmdp->cmdname, name);
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.
*/
void
addcmdentry(char *name, struct cmdentry *entry)
{
struct tblentry *cmdp;
INTOFF;
cmdp = cmdlookup(name, 1);
if (cmdp->cmdtype == CMDFUNCTION) {
freefunc(cmdp->param.func);
}
cmdp->cmdtype = entry->cmdtype;
cmdp->param = entry->u;
INTON;
}
/*
* Define a shell function.
*/
void
defun(char *name, union node *func)
{
struct cmdentry entry;
INTOFF;
entry.cmdtype = CMDFUNCTION;
entry.u.func = copyfunc(func);
addcmdentry(name, &entry);
INTON;
}
/*
* Delete a function if it exists.
*/
int
unsetfunc(char *name)
{
struct tblentry *cmdp;
if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
freefunc(cmdp->param.func);
delete_cmd_entry();
return (0);
}
return (0);
}
/*
* Shared code for the following builtin commands:
* type, command -v, command -V
*/
int
typecmd_impl(int argc, char **argv, int cmd)
{
struct cmdentry entry;
struct tblentry *cmdp;
char **pp;
struct alias *ap;
int i;
int error = 0;
extern char *const parsekwd[];
for (i = 1; i < argc; i++) {
if (cmd != TYPECMD_SMALLV)
out1str(argv[i]);
/* First look at the keywords */
for (pp = (char **)parsekwd; *pp; pp++)
if (**pp == *argv[i] && equal(*pp, argv[i]))
break;
if (*pp) {
if (cmd == TYPECMD_SMALLV)
out1fmt("%s\n", argv[i]);
else
out1str(" is a shell keyword\n");
continue;
}
/* Then look at the aliases */
if ((ap = lookupalias(argv[i], 1)) != NULL) {
if (cmd == TYPECMD_SMALLV)
out1fmt("alias %s='%s'\n", argv[i], ap->val);
else
out1fmt(" is an alias for %s\n", 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;
}
else {
/* Finally use brute force */
find_command(argv[i], &entry, 0, pathval());
}
switch (entry.cmdtype) {
case CMDNORMAL: {
if (strchr(argv[i], '/') == NULL) {
char *path = pathval(), *name;
int j = entry.u.index;
do {
name = padvance(&path, argv[i]);
stunalloc(name);
} while (--j >= 0);
if (cmd == TYPECMD_SMALLV)
out1fmt("%s\n", name);
else
out1fmt(" is%s %s\n",
(cmdp && cmd == TYPECMD_TYPE) ?
" a tracked alias for" : "",
name);
} else {
if (access(argv[i], X_OK) == 0) {
if (cmd == TYPECMD_SMALLV)
out1fmt("%s\n", argv[i]);
else
out1fmt(" is %s\n", argv[i]);
}
else
out1fmt(": %s\n", strerror(errno));
}
break;
}
case CMDFUNCTION:
if (cmd == TYPECMD_SMALLV)
out1fmt("%s\n", argv[i]);
else
out1str(" is a shell function\n");
break;
case CMDBUILTIN:
if (cmd == TYPECMD_SMALLV)
out1fmt("%s\n", argv[i]);
else
out1str(" is a shell builtin\n");
break;
default:
if (cmd != TYPECMD_SMALLV)
out1str(": not found\n");
error |= 127;
break;
}
}
return error;
}
/*
* Locate and print what a word is...
*/
int
typecmd(int argc, char **argv)
{
return typecmd_impl(argc, argv, TYPECMD_TYPE);
}