freebsd-dev/sys/boot/common/interp.c
Luigi Rizzo ade303f361 As reported in kern/118222, pxeboot in RELENG7 (and presumably
above) exhibits some misbehaviours on machines with AMD64 CPUs,
which at least in some cases I have tracked down to a heap overflow.

It is unclear whether it depends on the CPU or on the pxe bios
itself which may use more memory on AMD machines.

Noticeably a pxeboot compiled from 6.x sources works fine on all
machines I have tried so far, while a pxeboot compiled from 7.x
sources does not.

This patch is a first step in reducing the amount of memory used
while processing the configuration files read by the loader at boot
(some of them are quite large, 1700+ lines), and it does so by:
+ moving a buffer to static memory instead of allocating in the heap;
+ skipping empty lines;
+ reducing the amount of memory used for line descriptors;

Unfortunately there are several changes between 6.x and above,
affecting the compiler, the loader code itself, and libstand,
and it is not so straightforward to
These changes fix the behaviour on one motherboard with a
single-core AMD cpu, but are still not enough e.g on an Asus
M2N-VM (with a dual-core CPU).

I need to investigate the problem a bit more before figuring
out what should be committed to RELENG_7

PR:		kern/118222
2008-11-20 14:57:09 +00:00

355 lines
7.9 KiB
C

/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Simple commandline interpreter, toplevel and misc.
*
* XXX may be obsoleted by BootFORTH or some other, better, interpreter.
*/
#include <stand.h>
#include <string.h>
#include "bootstrap.h"
#ifdef BOOT_FORTH
#include "ficl.h"
#define RETURN(x) stackPushINT(bf_vm->pStack,!x); return(x)
extern FICL_VM *bf_vm;
#else
#define RETURN(x) return(x)
#endif
#define MAXARGS 20 /* maximum number of arguments allowed */
static void prompt(void);
#ifndef BOOT_FORTH
static int perform(int argc, char *argv[]);
/*
* Perform the command
*/
int
perform(int argc, char *argv[])
{
int result;
struct bootblk_command **cmdp;
bootblk_cmd_t *cmd;
if (argc < 1)
return(CMD_OK);
/* set return defaults; a successful command will override these */
command_errmsg = command_errbuf;
strcpy(command_errbuf, "no error message");
cmd = NULL;
result = CMD_ERROR;
/* search the command set for the command */
SET_FOREACH(cmdp, Xcommand_set) {
if (((*cmdp)->c_name != NULL) && !strcmp(argv[0], (*cmdp)->c_name))
cmd = (*cmdp)->c_fn;
}
if (cmd != NULL) {
result = (cmd)(argc, argv);
} else {
command_errmsg = "unknown command";
}
RETURN(result);
}
#endif /* ! BOOT_FORTH */
/*
* Interactive mode
*/
void
interact(void)
{
static char input[256]; /* big enough? */
#ifndef BOOT_FORTH
int argc;
char **argv;
#endif
#ifdef BOOT_FORTH
bf_init();
#endif
/*
* Read our default configuration
*/
if(include("/boot/loader.rc")!=CMD_OK)
include("/boot/boot.conf");
printf("\n");
/*
* Before interacting, we might want to autoboot.
*/
autoboot_maybe();
/*
* Not autobooting, go manual
*/
printf("\nType '?' for a list of commands, 'help' for more detailed help.\n");
if (getenv("prompt") == NULL)
setenv("prompt", "${interpret}", 1);
if (getenv("interpret") == NULL)
setenv("interpret", "OK", 1);
for (;;) {
input[0] = '\0';
prompt();
ngets(input, sizeof(input));
#ifdef BOOT_FORTH
bf_vm->sourceID.i = 0;
bf_run(input);
#else
if (!parse(&argc, &argv, input)) {
if (perform(argc, argv))
printf("%s: %s\n", argv[0], command_errmsg);
free(argv);
} else {
printf("parse error\n");
}
#endif
}
}
/*
* Read commands from a file, then execute them.
*
* We store the commands in memory and close the source file so that the media
* holding it can safely go away while we are executing.
*
* Commands may be prefixed with '@' (so they aren't displayed) or '-' (so
* that the script won't stop if they fail).
*/
COMMAND_SET(include, "include", "read commands from a file", command_include);
static int
command_include(int argc, char *argv[])
{
int i;
int res;
char **argvbuf;
/*
* Since argv is static, we need to save it here.
*/
argvbuf = (char**) calloc((u_int)argc, sizeof(char*));
for (i = 0; i < argc; i++)
argvbuf[i] = strdup(argv[i]);
res=CMD_OK;
for (i = 1; (i < argc) && (res == CMD_OK); i++)
res = include(argvbuf[i]);
for (i = 0; i < argc; i++)
free(argvbuf[i]);
free(argvbuf);
return(res);
}
/*
* Header prepended to each line. The text immediately follows the header.
* We try to make this short in order to save memory -- the loader has
* limited memory available, and some of the forth files are very long.
*/
struct includeline
{
struct includeline *next;
#ifndef BOOT_FORTH
int flags;
int line;
#define SL_QUIET (1<<0)
#define SL_IGNOREERR (1<<1)
#endif
char text[0];
};
int
include(const char *filename)
{
struct includeline *script, *se, *sp;
char input[256]; /* big enough? */
#ifdef BOOT_FORTH
int res;
char *cp;
int prevsrcid, fd, line;
#else
int argc,res;
char **argv, *cp;
int fd, flags, line;
#endif
if (((fd = open(filename, O_RDONLY)) == -1)) {
sprintf(command_errbuf,"can't open '%s': %s\n", filename, strerror(errno));
return(CMD_ERROR);
}
/*
* Read the script into memory.
*/
script = se = NULL;
line = 0;
while (fgetstr(input, sizeof(input), fd) >= 0) {
line++;
#ifdef BOOT_FORTH
cp = input;
#else
flags = 0;
/* Discard comments */
if (strncmp(input+strspn(input, " "), "\\ ", 2) == 0)
continue;
cp = input;
/* Echo? */
if (input[0] == '@') {
cp++;
flags |= SL_QUIET;
}
/* Error OK? */
if (input[0] == '-') {
cp++;
flags |= SL_IGNOREERR;
}
#endif
/* Allocate script line structure and copy line, flags */
if (*cp == '\0')
continue; /* ignore empty line, save memory */
sp = malloc(sizeof(struct includeline) + strlen(cp) + 1);
strcpy(sp->text, cp);
#ifndef BOOT_FORTH
sp->flags = flags;
sp->line = line;
#endif
sp->next = NULL;
if (script == NULL) {
script = sp;
} else {
se->next = sp;
}
se = sp;
}
close(fd);
/*
* Execute the script
*/
#ifndef BOOT_FORTH
argv = NULL;
#else
prevsrcid = bf_vm->sourceID.i;
bf_vm->sourceID.i = fd;
#endif
res = CMD_OK;
for (sp = script; sp != NULL; sp = sp->next) {
#ifdef BOOT_FORTH
res = bf_run(sp->text);
if (res != VM_OUTOFTEXT) {
sprintf(command_errbuf, "Error while including %s, in the line:\n%s", filename, sp->text);
res = CMD_ERROR;
break;
} else
res = CMD_OK;
#else
/* print if not being quiet */
if (!(sp->flags & SL_QUIET)) {
prompt();
printf("%s\n", sp->text);
}
/* Parse the command */
if (!parse(&argc, &argv, sp->text)) {
if ((argc > 0) && (perform(argc, argv) != 0)) {
/* normal command */
printf("%s: %s\n", argv[0], command_errmsg);
if (!(sp->flags & SL_IGNOREERR)) {
res=CMD_ERROR;
break;
}
}
free(argv);
argv = NULL;
} else {
printf("%s line %d: parse error\n", filename, sp->line);
res=CMD_ERROR;
break;
}
#endif
}
#ifndef BOOT_FORTH
if (argv != NULL)
free(argv);
#else
bf_vm->sourceID.i = prevsrcid;
#endif
while(script != NULL) {
se = script;
script = script->next;
free(se);
}
return(res);
}
/*
* Emit the current prompt; use the same syntax as the parser
* for embedding environment variables.
*/
static void
prompt(void)
{
char *pr, *p, *cp, *ev;
if ((cp = getenv("prompt")) == NULL)
cp = ">";
pr = p = strdup(cp);
while (*p != 0) {
if ((*p == '$') && (*(p+1) == '{')) {
for (cp = p + 2; (*cp != 0) && (*cp != '}'); cp++)
;
*cp = 0;
ev = getenv(p + 2);
if (ev != NULL)
printf("%s", ev);
p = cp + 1;
continue;
}
putchar(*p++);
}
putchar(' ');
free(pr);
}