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/* virt-p2v
* Copyright (C) 2015 Red Hat Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/**
* Mini library to read and parse C</proc/cmdline>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <error.h>
#include "getprogname.h"
#include "p2v.h"
static void
add_null (char ***argv, size_t *lenp)
{
(*lenp)++;
*argv = realloc (*argv, *lenp * sizeof (char *));
if (*argv == NULL)
error (EXIT_FAILURE, errno, "realloc");
(*argv)[(*lenp)-1] = NULL;
}
static void
add_string (char ***argv, size_t *lenp, const char *str, size_t len)
{
add_null (argv, lenp);
(*argv)[(*lenp)-1] = strndup (str, len);
if ((*argv)[(*lenp)-1] == NULL)
error (EXIT_FAILURE, errno, "strndup");
}
/**
* Read and parse C</proc/cmdline>.
*
* We only support double quoting, consistent with the Linux
* documentation.
* L<https://www.kernel.org/doc/Documentation/kernel-parameters.txt>
*
* systemd supports single and double quoting and single character
* escaping, but we don't support all that.
*
* Returns a list of key, value pairs, terminated by C<NULL>.
*/
char **
parse_cmdline_string (const char *cmdline)
{
char **ret = NULL;
size_t len = 0;
const char *p, *key = NULL, *value = NULL;
enum {
KEY_START = 0,
KEY,
VALUE_START,
VALUE,
VALUE_QUOTED
} state = 0;
for (p = cmdline; *p; p++) {
switch (state) {
case KEY_START: /* looking for the start of a key */
if (*p == ' ') continue;
key = p;
state = KEY;
break;
case KEY: /* reading key */
if (*p == ' ') {
add_string (&ret, &len, key, p-key);
add_string (&ret, &len, "", 0);
state = KEY_START;
}
else if (*p == '=') {
add_string (&ret, &len, key, p-key);
state = VALUE_START;
}
break;
case VALUE_START: /* looking for the start of a value */
if (*p == ' ') {
add_string (&ret, &len, "", 0);
state = KEY_START;
}
else if (*p == '"') {
value = p+1;
state = VALUE_QUOTED;
}
else {
value = p;
state = VALUE;
}
break;
case VALUE: /* reading unquoted value */
if (*p == ' ') {
add_string (&ret, &len, value, p-value);
state = KEY_START;
}
break;
case VALUE_QUOTED: /* reading quoted value */
if (*p == '"') {
add_string (&ret, &len, value, p-value);
state = KEY_START;
}
break;
}
}
switch (state) {
case KEY_START: break;
case KEY: /* key followed by end of string */
add_string (&ret, &len, key, p-key);
add_string (&ret, &len, "", 0);
break;
case VALUE_START: /* key= followed by end of string */
add_string (&ret, &len, "", 0);
break;
case VALUE: /* key=value followed by end of string */
add_string (&ret, &len, value, p-value);
break;
case VALUE_QUOTED: /* unterminated key="value" */
fprintf (stderr, "%s: warning: unterminated quoted string on kernel command line\n",
getprogname ());
add_string (&ret, &len, value, p-value);
}
add_null (&ret, &len);
return ret;
}
char **
parse_proc_cmdline (void)
{
CLEANUP_FCLOSE FILE *fp = NULL;
CLEANUP_FREE char *cmdline = NULL;
size_t len = 0;
fp = fopen ("/proc/cmdline", "re");
if (fp == NULL) {
perror ("/proc/cmdline");
return NULL;
}
if (getline (&cmdline, &len, fp) == -1) {
perror ("getline");
return NULL;
}
/* 'len' is not the length of the string, but the length of the
* buffer. We need to chomp the string.
*/
len = strlen (cmdline);
if (len >= 1 && cmdline[len-1] == '\n')
cmdline[len-1] = '\0';
return parse_cmdline_string (cmdline);
}
const char *
get_cmdline_key (char **argv, const char *key)
{
size_t i;
for (i = 0; argv[i] != NULL; i += 2) {
if (STREQ (argv[i], key))
return argv[i+1];
}
/* Not found. */
return NULL;
}
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