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NetBSD/sys/lib/libsa/bootcfg.c

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/* $NetBSD: bootcfg.c,v 1.6 2021/05/30 05:59:23 mlelstv Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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/reboot.h>
#include <lib/libsa/stand.h>
#include <lib/libsa/bootcfg.h>
#include <lib/libkern/libkern.h>
#define MENUFORMAT_AUTO 0
#define MENUFORMAT_NUMBER 1
#define MENUFORMAT_LETTER 2
#define DEFAULT_FORMAT MENUFORMAT_AUTO
#define DEFAULT_TIMEOUT 10
struct bootcfg_def bootcfg_info;
void
bootcfg_do_noop(const char *cmd, char *arg)
{
/* noop, do nothing */
}
/*
* This function parses a boot.cfg file in the root of the filesystem
* (if present) and populates the global boot configuration.
*
* The file consists of a number of lines each terminated by \n
* The lines are in the format keyword=value. There should not be spaces
* around the = sign.
*
* perform_bootcfg(conf, command, maxsz)
*
* conf Path to boot.cfg to be passed verbatim to open()
*
* command Pointer to a function that will be called when
* perform_bootcfg() encounters a key (command) it does not
* recognize.
* The command function is provided both the keyword and
* value parsed as arguments to the function.
*
* maxsz Limit the size of the boot.cfg perform_bootcfg() will parse.
* - If maxsz is < 0 boot.cfg will not be processed.
* - If maxsz is = 0 no limit will be imposed but parsing may
* fail due to platform or other constraints e.g. maximum
* segment size.
* - If 0 < maxsz and boot.cfg exceeds maxsz it will not be
* parsed, otherwise it will be parsed.
*
* The recognised keywords are:
* banner: text displayed instead of the normal welcome text
* menu: Descriptive text:command to use
* timeout: Timeout in seconds (overrides that set by installboot)
* default: the default menu option to use if Return is pressed
* consdev: the console device to use
* root: the root device to use
* format: how menu choices are displayed: (a)utomatic, (n)umbers or (l)etters
* clear: whether to clear the screen or not
*
* Example boot.cfg file:
* banner=Welcome to NetBSD
* banner=Please choose the boot type from the following menu
* menu=Boot NetBSD:boot netbsd
* menu=Boot into single user mode:boot netbsd -s
* menu=:boot hd1a:netbsd -cs
* menu=Goto boot comand line:prompt
* timeout=10
* consdev=com0
* default=1
*/
int
perform_bootcfg(const char *conf, bootcfg_command command, const off_t maxsz)
{
char *bc, *c;
int cmenu, cbanner;
ssize_t len, off, resid;
int fd, err;
struct stat st;
char *next, *key, *value, *v2;
/* clear bootcfg structure */
memset(&bootcfg_info, 0, sizeof(bootcfg_info));
/* set default timeout */
bootcfg_info.timeout = DEFAULT_TIMEOUT;
/* automatically switch between letter and numbers on menu */
bootcfg_info.menuformat = DEFAULT_FORMAT;
fd = open(conf, 0);
if (fd < 0)
return ENOENT;
err = fstat(fd, &st);
if (err == -1) {
/* file descriptor may not be backed by a libsa file-system */
st.st_size = maxsz;
}
/* if a maximum size is being requested for the boot.cfg enforce it. */
if (0 < maxsz && st.st_size > maxsz) {
close(fd);
return EFBIG;
}
bc = alloc((size_t)st.st_size + 1);
if (bc == NULL) {
printf("Could not allocate memory for boot configuration\n");
close(fd);
return ENOMEM;
}
/*
* XXX original code, assumes error or eof return from read()
* results in the entire boot.cfg being buffered.
* - should bail out on read() failing.
* - assumption is made that the file size doesn't change between
* fstat() and read()ing. probably safe in this context
* arguably should check that reading the file won't overflow
* the storage anyway.
*/
off = 0;
resid = st.st_size;
do {
len = read(fd, bc + off, uimin(1024, resid));
if (len <= 0)
break;
off += len;
resid -= len;
} while (len > 0 && resid > 0);
bc[off] = '\0';
close(fd);
/* bc is now assumed to contain the whole boot.cfg file (see above) */
cmenu = 0;
cbanner = 0;
for (c = bc; *c; c = next) {
key = c;
/* find end of line */
for (; *c && *c != '\n'; c++)
/* zero terminate line on start of comment */
if (*c == '#')
*c = 0;
/* zero terminate line */
if (*(next = c))
*next++ = 0;
/* Look for = separator between key and value */
for (c = key; *c && *c != '='; c++)
continue;
/* Ignore lines with no key=value pair */
if (*c == '\0')
continue;
/* zero terminate key which points to keyword */
*c++ = 0;
value = c;
/* Look for end of line (or file) and zero terminate value */
for (; *c && *c != '\n'; c++)
continue;
*c = 0;
if (!strncmp(key, "menu", 4)) {
/*
* Parse "menu=<description>:<command>". If the
* description is empty ("menu=:<command>)",
* then re-use the command as the description.
* Note that the command may contain embedded
* colons.
*/
if (cmenu >= BOOTCFG_MAXMENU)
continue;
bootcfg_info.desc[cmenu] = value;
for (v2 = value; *v2 && *v2 != ':'; v2++)
continue;
if (*v2) {
*v2++ = 0;
bootcfg_info.command[cmenu] = v2;
if (! *value)
bootcfg_info.desc[cmenu] = v2;
cmenu++;
} else {
/* No delimiter means invalid line */
bootcfg_info.desc[cmenu] = NULL;
}
} else if (!strncmp(key, "banner", 6)) {
if (cbanner < BOOTCFG_MAXBANNER)
bootcfg_info.banner[cbanner++] = value;
} else if (!strncmp(key, "timeout", 7)) {
if (!isdigit(*value))
bootcfg_info.timeout = -1;
else
bootcfg_info.timeout = atoi(value);
} else if (!strncmp(key, "default", 7)) {
bootcfg_info.def = atoi(value) - 1;
} else if (!strncmp(key, "consdev", 7)) {
bootcfg_info.consdev = value;
} else if (!strncmp(key, "root", 4)) {
bootcfg_info.root = value;
} else if (!strncmp(key, BOOTCFG_CMD_LOAD, 4)) {
command(BOOTCFG_CMD_LOAD, value);
} else if (!strncmp(key, "format", 6)) {
printf("value:%c\n", *value);
switch (*value) {
case 'a':
case 'A':
bootcfg_info.menuformat = MENUFORMAT_AUTO;
break;
case 'n':
case 'N':
case 'd':
case 'D':
bootcfg_info.menuformat = MENUFORMAT_NUMBER;
break;
case 'l':
case 'L':
bootcfg_info.menuformat = MENUFORMAT_LETTER;
break;
}
} else if (!strncmp(key, "clear", 5)) {
bootcfg_info.clear = !!atoi(value);
} else if (!strncmp(key, BOOTCFG_CMD_USERCONF, 8)) {
command(BOOTCFG_CMD_USERCONF, value);
} else {
command(key, value);
}
}
switch (bootcfg_info.menuformat) {
case MENUFORMAT_AUTO:
if (cmenu > 9 && bootcfg_info.timeout > 0)
bootcfg_info.menuformat = MENUFORMAT_LETTER;
else
bootcfg_info.menuformat = MENUFORMAT_NUMBER;
break;
case MENUFORMAT_NUMBER:
if (cmenu > 9 && bootcfg_info.timeout > 0)
cmenu = 9;
break;
}
bootcfg_info.nummenu = cmenu;
if (bootcfg_info.def < 0)
bootcfg_info.def = 0;
if (bootcfg_info.def >= cmenu)
bootcfg_info.def = cmenu - 1;
return 0;
}
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