blob: 4b777d23bcb43bbb46f597c43a2595521e6d8e09 [file] [log] [blame]
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 1997-2005
* Herbert Xu <herbert@gondor.apana.org.au>. 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 <unistd.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
#ifdef HAVE_PATHS_H
#include <paths.h>
#endif
/*
* 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 "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"
#include "system.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 */
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 */
STATIC void tryexec(char *, char **, char **);
STATIC void printentry(struct tblentry *);
STATIC void clearcmdentry(void);
STATIC struct tblentry *cmdlookup(const char *, int);
STATIC void delete_cmd_entry(void);
STATIC void addcmdentry(char *, struct cmdentry *);
STATIC int describe_command(struct output *, char *, const char *, int);
/*
* 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, const char *path, int idx)
{
char *cmdname;
int e;
char **envp;
int exerrno;
envp = environment();
if (strchr(argv[0], '/') != NULL) {
tryexec(argv[0], argv, envp);
e = errno;
} else {
e = ENOENT;
while (padvance(&path, argv[0]) >= 0) {
cmdname = stackblock();
if (--idx < 0 && pathopt == NULL) {
tryexec(cmdname, argv, envp);
if (errno != ENOENT && errno != ENOTDIR)
e = errno;
}
}
}
/* Map to POSIX errors */
switch (e) {
default:
exerrno = 126;
break;
case ELOOP:
case ENAMETOOLONG:
case ENOENT:
case ENOTDIR:
exerrno = 127;
break;
}
exitstatus = exerrno;
TRACE(("shellexec failed for %s, errno %d, suppressint %d\n",
argv[0], e, suppressint ));
exerror(EXEND, "%s: %s", argv[0], errmsg(e, E_EXEC));
/* NOTREACHED */
}
STATIC void
tryexec(char *cmd, char **argv, char **envp)
{
char *const path_bshell = _PATH_BSHELL;
repeat:
#ifdef SYSV
do {
execve(cmd, argv, envp);
} while (errno == EINTR);
#else
execve(cmd, argv, envp);
#endif
if (cmd != path_bshell && errno == ENOEXEC) {
*argv-- = cmd;
*argv = cmd = path_bshell;
goto repeat;
}
}
static const char *legal_pathopt(const char *opt, const char *term, int magic)
{
switch (magic) {
case 0:
opt = NULL;
break;
case 1:
opt = prefix(opt, "builtin") ?: prefix(opt, "func");
break;
default:
opt += strcspn(opt, term);
break;
}
if (opt && *opt == '%')
opt++;
return opt;
}
/*
* 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.
*
* If magic is 0 then pathopt recognition will be disabled. If magic is
* 1 we shall recognise %builtin/%func. Otherwise we shall accept any
* pathopt.
*/
const char *pathopt;
int padvance_magic(const char **path, const char *name, int magic)
{
const char *term = "%:";
const char *lpathopt;
const char *p;
char *q;
const char *start;
size_t qlen;
size_t len;
if (*path == NULL)
return -1;
lpathopt = NULL;
start = *path;
if (*start == '%' && (p = legal_pathopt(start + 1, term, magic))) {
lpathopt = start + 1;
start = p;
term = ":";
}
len = strcspn(start, term);
p = start + len;
if (*p == '%') {
size_t extra = strchrnul(p, ':') - p;
if (legal_pathopt(p + 1, term, magic))
lpathopt = p + 1;
else
len += extra;
p += extra;
}
pathopt = lpathopt;
*path = *p == ':' ? p + 1 : NULL;
/* "2" is for '/' and '\0' */
qlen = len + strlen(name) + 2;
q = growstackto(qlen);
if (likely(len)) {
q = mempcpy(q, start, len);
*q++ = '/';
}
strcpy(q, name);
return qlen;
}
/*** Command hashing code ***/
int
hashcmd(int argc, char **argv)
{
struct tblentry **pp;
struct tblentry *cmdp;
int c;
struct cmdentry entry;
char *name;
bool clear;
clear = false;
while ((c = nextopt("r")) != '\0')
clear = true;
if(clear) {
clearcmdentry();
return 0;
}
if (*argptr == NULL) {
for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
if (cmdp->cmdtype == CMDNORMAL)
printentry(cmdp);
}
}
return 0;
}
c = 0;
while ((name = *argptr) != NULL) {
if ((cmdp = cmdlookup(name, 0)) &&
(cmdp->cmdtype == CMDNORMAL ||
(cmdp->cmdtype == CMDBUILTIN &&
!(cmdp->param.cmd->flags & BUILTIN_REGULAR) &&
builtinloc > 0)))
delete_cmd_entry();
find_command(name, &entry, DO_ERR, pathval());
if (entry.cmdtype == CMDUNKNOWN)
c = 1;
argptr++;
}
return c;
}
STATIC void
printentry(struct tblentry *cmdp)
{
int idx;
const char *path;
char *name;
idx = cmdp->param.index;
path = pathval();
do {
padvance(&path, cmdp->cmdname);
} while (--idx >= 0);
name = stackblock();
out1str(name);
out1fmt(snlfmt, cmdp->rehash ? "*" : nullstr);
}
/*
* 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 act, const char *path)
{
struct tblentry *cmdp;
int idx;
int prev;
char *fullname;
struct stat64 statb;
int e;
int updatetbl;
struct builtincmd *bcmd;
int len;
/* If name contains a slash, don't use PATH or hash table */
if (strchr(name, '/') != NULL) {
entry->u.index = -1;
if (act & DO_ABS) {
while (stat64(name, &statb) < 0) {
#ifdef SYSV
if (errno == EINTR)
continue;
#endif
entry->cmdtype = CMDUNKNOWN;
return;
}
}
entry->cmdtype = CMDNORMAL;
return;
}
updatetbl = (path == pathval());
if (!updatetbl)
act |= DO_ALTPATH;
/* If name is in the table, check answer will be ok */
if ((cmdp = cmdlookup(name, 0)) != NULL) {
int bit;
switch (cmdp->cmdtype) {
default:
#if DEBUG
abort();
#endif
case CMDNORMAL:
bit = DO_ALTPATH | DO_REGBLTIN;
break;
case CMDFUNCTION:
bit = DO_NOFUNC;
break;
case CMDBUILTIN:
bit = cmdp->param.cmd->flags & BUILTIN_REGULAR ?
0 : DO_REGBLTIN;
break;
}
if (act & bit) {
if (act & bit & DO_REGBLTIN)
goto fail;
updatetbl = 0;
cmdp = NULL;
} else if (cmdp->rehash == 0)
/* if not invalidated by cd, we're done */
goto success;
}
/* If %builtin not in path, check for builtin next */
bcmd = find_builtin(name);
if (bcmd && ((bcmd->flags & BUILTIN_REGULAR) | (act & DO_ALTPATH) |
(builtinloc <= 0)))
goto builtin_success;
if (act & DO_REGBLTIN)
goto fail;
/* We have to search path. */
prev = -1; /* where to start */
if (cmdp && cmdp->rehash) { /* doing a rehash */
if (cmdp->cmdtype == CMDBUILTIN)
prev = builtinloc;
else
prev = cmdp->param.index;
}
e = ENOENT;
idx = -1;
loop:
while ((len = padvance(&path, name)) >= 0) {
const char *lpathopt = pathopt;
fullname = stackblock();
idx++;
if (lpathopt) {
if (*lpathopt == 'b') {
if (bcmd)
goto builtin_success;
continue;
} else if (!(act & DO_NOFUNC)) {
/* handled below */
} else {
/* ignore unimplemented options */
continue;
}
}
/* if rehash, don't redo absolute path names */
if (fullname[0] == '/' && idx <= prev) {
if (idx < prev)
continue;
TRACE(("searchexec \"%s\": no change\n", name));
goto success;
}
while (stat64(fullname, &statb) < 0) {
#ifdef SYSV
if (errno == EINTR)
continue;
#endif
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))
continue;
if (lpathopt) { /* this is a %func directory */
stalloc(len);
readcmdfile(fullname);
if ((cmdp = cmdlookup(name, 0)) == NULL ||
cmdp->cmdtype != CMDFUNCTION)
sh_error("%s not defined in %s", name,
fullname);
stunalloc(fullname);
goto success;
}
#ifdef notdef
/* XXX this code stops root executing stuff, and is buggy
if you need a group from the group list. */
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));
if (!updatetbl) {
entry->cmdtype = CMDNORMAL;
entry->u.index = idx;
return;
}
INTOFF;
cmdp = cmdlookup(name, 1);
cmdp->cmdtype = CMDNORMAL;
cmdp->param.index = idx;
INTON;
goto success;
}
/* We failed. If there was an entry for this command, delete it */
if (cmdp && updatetbl)
delete_cmd_entry();
if (act & DO_ERR)
sh_warnx("%s: %s", name, errmsg(e, E_EXEC));
fail:
entry->cmdtype = CMDUNKNOWN;
return;
builtin_success:
if (!updatetbl) {
entry->cmdtype = CMDBUILTIN;
entry->u.cmd = bcmd;
return;
}
INTOFF;
cmdp = cmdlookup(name, 1);
cmdp->cmdtype = CMDBUILTIN;
cmdp->param.cmd = bcmd;
INTON;
success:
cmdp->rehash = 0;
entry->cmdtype = cmdp->cmdtype;
entry->u = cmdp->param;
}
/*
* Search the table of builtin commands.
*/
struct builtincmd *
find_builtin(const char *name)
{
struct builtincmd *bp;
bp = bsearch(
&name, builtincmd, NUMBUILTINS, sizeof(struct builtincmd),
pstrcmp
);
return bp;
}
/*
* 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 &&
!(cmdp->param.cmd->flags & BUILTIN_REGULAR) &&
builtinloc > 0
))
cmdp->rehash = 1;
}
}
}
/*
* Fix command hash table when PATH changed.
* 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 *new;
int idx;
int bltin;
new = newval;
idx = 0;
bltin = -1;
for (;;) {
if (*new == '%' && prefix(new + 1, "builtin")) {
bltin = idx;
break;
}
new = strchr(new, ':');
if (!new)
break;
idx++;
new++;
}
builtinloc = bltin;
clearcmdentry();
}
/*
* Clear out command entries. The argument specifies the first entry in
* PATH which has changed.
*/
STATIC 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 ||
(cmdp->cmdtype == CMDBUILTIN &&
!(cmdp->param.cmd->flags & BUILTIN_REGULAR) &&
builtinloc > 0)) {
*pp = cmdp->next;
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.
*
* Interrupts must be off if called with add != 0.
*/
struct tblentry **lastcmdentry;
STATIC struct tblentry *
cmdlookup(const char *name, int add)
{
unsigned int hashval;
const char *p;
struct tblentry *cmdp;
struct tblentry **pp;
p = name;
hashval = (unsigned char)*p << 4;
while (*p)
hashval += (unsigned char)*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) {
cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
+ strlen(name) + 1);
cmdp->next = NULL;
cmdp->cmdtype = CMDUNKNOWN;
strcpy(cmdp->cmdname, name);
}
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;
if (cmdp->cmdtype == CMDFUNCTION)
freefunc(cmdp->param.func);
ckfree(cmdp);
INTON;
}
#ifdef notdef
void
getcmdentry(char *name, struct cmdentry *entry)
{
struct tblentry *cmdp = cmdlookup(name, 0);
if (cmdp) {
entry->u = cmdp->param;
entry->cmdtype = cmdp->cmdtype;
} else {
entry->cmdtype = CMDUNKNOWN;
entry->u.index = 0;
}
}
#endif
/*
* Add a new command entry, replacing any existing command entry for
* the same name - except special builtins.
*/
STATIC void
addcmdentry(char *name, struct cmdentry *entry)
{
struct tblentry *cmdp;
cmdp = cmdlookup(name, 1);
if (cmdp->cmdtype == CMDFUNCTION) {
freefunc(cmdp->param.func);
}
cmdp->cmdtype = entry->cmdtype;
cmdp->param = entry->u;
cmdp->rehash = 0;
}
/*
* Define a shell function.
*/
void
defun(union node *func)
{
struct cmdentry entry;
INTOFF;
entry.cmdtype = CMDFUNCTION;
entry.u.func = copyfunc(func);
addcmdentry(func->ndefun.text, &entry);
INTON;
}
/*
* Delete a function if it exists.
*/
void
unsetfunc(const char *name)
{
struct tblentry *cmdp;
if ((cmdp = cmdlookup(name, 0)) != NULL &&
cmdp->cmdtype == CMDFUNCTION)
delete_cmd_entry();
}
/*
* Locate and print what a word is...
*/
int
typecmd(int argc, char **argv)
{
int err = 0;
nextopt(nullstr);
while (*argptr) {
err |= describe_command(out1, *argptr++, NULL, 1);
}
return err;
}
static int describe_command(struct output *out, char *command,
const char *path, int verbose)
{
struct cmdentry entry;
struct tblentry *cmdp;
const struct alias *ap;
if (verbose) {
outstr(command, out);
}
/* First look at the keywords */
if (findkwd(command)) {
outstr(verbose ? " is a shell keyword" : command, out);
goto out;
}
/* Then look at the aliases */
if ((ap = lookupalias(command, 0)) != NULL) {
if (verbose) {
outfmt(out, " is an alias for %s", ap->val);
} else {
outstr("alias ", out);
printalias(ap);
return 0;
}
goto out;
}
/* Then if the standard search path is used, check if it is
* a tracked alias.
*/
if (path == NULL) {
path = pathval();
cmdp = cmdlookup(command, 0);
} else {
cmdp = NULL;
}
if (cmdp != NULL) {
entry.cmdtype = cmdp->cmdtype;
entry.u = cmdp->param;
} else {
/* Finally use brute force */
find_command(command, &entry, DO_ABS, path);
}
switch (entry.cmdtype) {
case CMDNORMAL: {
int j = entry.u.index;
char *p;
if (j == -1) {
p = command;
} else {
do {
padvance(&path, command);
} while (--j >= 0);
p = stackblock();
}
if (verbose) {
outfmt(
out, " is%s %s",
cmdp ? " a tracked alias for" : nullstr, p
);
} else {
outstr(p, out);
}
break;
}
case CMDFUNCTION:
if (verbose) {
outstr(" is a shell function", out);
} else {
outstr(command, out);
}
break;
case CMDBUILTIN:
if (verbose) {
outfmt(
out, " is a %sshell builtin",
entry.u.cmd->flags & BUILTIN_SPECIAL ?
"special " : nullstr
);
} else {
outstr(command, out);
}
break;
default:
if (verbose) {
outstr(": not found\n", out);
}
return 127;
}
out:
outc('\n', out);
return 0;
}
int commandcmd(int argc, char **argv)
{
char *cmd;
int c;
enum {
VERIFY_BRIEF = 1,
VERIFY_VERBOSE = 2,
} verify = 0;
const char *path = NULL;
while ((c = nextopt("pvV")) != '\0')
if (c == 'V')
verify |= VERIFY_VERBOSE;
else if (c == 'v')
verify |= VERIFY_BRIEF;
#ifdef DEBUG
else if (c != 'p')
abort();
#endif
else
path = defpath;
cmd = *argptr;
if (verify && cmd)
return describe_command(out1, cmd, path, verify - VERIFY_BRIEF);
return 0;
}