1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
|
// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Misc librarized functions for cmdline poking.
*/
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <asm/setup.h>
#include <asm/cmdline.h>
#include <asm/bug.h>
static inline int myisspace(u8 c)
{
return c <= ' '; /* Close enough approximation */
}
/*
* Find a boolean option (like quiet,noapic,nosmp....)
*
* @cmdline: the cmdline string
* @max_cmdline_size: the maximum size of cmdline
* @option: option string to look for
*
* Returns the position of that @option (starts counting with 1)
* or 0 on not found. @option will only be found if it is found
* as an entire word in @cmdline. For instance, if @option="car"
* then a cmdline which contains "cart" will not match.
*/
static int
__cmdline_find_option_bool(const char *cmdline, int max_cmdline_size,
const char *option)
{
char c;
int pos = 0, wstart = 0;
const char *opptr = NULL;
enum {
st_wordstart = 0, /* Start of word/after whitespace */
st_wordcmp, /* Comparing this word */
st_wordskip, /* Miscompare, skip */
} state = st_wordstart;
if (!cmdline)
return -1; /* No command line */
/*
* This 'pos' check ensures we do not overrun
* a non-NULL-terminated 'cmdline'
*/
while (pos < max_cmdline_size) {
c = *(char *)cmdline++;
pos++;
switch (state) {
case st_wordstart:
if (!c)
return 0;
else if (myisspace(c))
break;
state = st_wordcmp;
opptr = option;
wstart = pos;
fallthrough;
case st_wordcmp:
if (!*opptr) {
/*
* We matched all the way to the end of the
* option we were looking for. If the
* command-line has a space _or_ ends, then
* we matched!
*/
if (!c || myisspace(c))
return wstart;
/*
* We hit the end of the option, but _not_
* the end of a word on the cmdline. Not
* a match.
*/
} else if (!c) {
/*
* Hit the NULL terminator on the end of
* cmdline.
*/
return 0;
} else if (c == *opptr++) {
/*
* We are currently matching, so continue
* to the next character on the cmdline.
*/
break;
}
state = st_wordskip;
fallthrough;
case st_wordskip:
if (!c)
return 0;
else if (myisspace(c))
state = st_wordstart;
break;
}
}
return 0; /* Buffer overrun */
}
/*
* Find a non-boolean option (i.e. option=argument). In accordance with
* standard Linux practice, if this option is repeated, this returns the
* last instance on the command line.
*
* @cmdline: the cmdline string
* @max_cmdline_size: the maximum size of cmdline
* @option: option string to look for
* @buffer: memory buffer to return the option argument
* @bufsize: size of the supplied memory buffer
*
* Returns the length of the argument (regardless of if it was
* truncated to fit in the buffer), or -1 on not found.
*/
static int
__cmdline_find_option(const char *cmdline, int max_cmdline_size,
const char *option, char *buffer, int bufsize)
{
char c;
int pos = 0, len = -1;
const char *opptr = NULL;
char *bufptr = buffer;
enum {
st_wordstart = 0, /* Start of word/after whitespace */
st_wordcmp, /* Comparing this word */
st_wordskip, /* Miscompare, skip */
st_bufcpy, /* Copying this to buffer */
} state = st_wordstart;
if (!cmdline)
return -1; /* No command line */
/*
* This 'pos' check ensures we do not overrun
* a non-NULL-terminated 'cmdline'
*/
while (pos++ < max_cmdline_size) {
c = *(char *)cmdline++;
if (!c)
break;
switch (state) {
case st_wordstart:
if (myisspace(c))
break;
state = st_wordcmp;
opptr = option;
fallthrough;
case st_wordcmp:
if ((c == '=') && !*opptr) {
/*
* We matched all the way to the end of the
* option we were looking for, prepare to
* copy the argument.
*/
len = 0;
bufptr = buffer;
state = st_bufcpy;
break;
} else if (c == *opptr++) {
/*
* We are currently matching, so continue
* to the next character on the cmdline.
*/
break;
}
state = st_wordskip;
fallthrough;
case st_wordskip:
if (myisspace(c))
state = st_wordstart;
break;
case st_bufcpy:
if (myisspace(c)) {
state = st_wordstart;
} else {
/*
* Increment len, but don't overrun the
* supplied buffer and leave room for the
* NULL terminator.
*/
if (++len < bufsize)
*bufptr++ = c;
}
break;
}
}
if (bufsize)
*bufptr = '\0';
return len;
}
int cmdline_find_option_bool(const char *cmdline, const char *option)
{
if (IS_ENABLED(CONFIG_CMDLINE_BOOL))
WARN_ON_ONCE(!builtin_cmdline_added);
return __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option);
}
int cmdline_find_option(const char *cmdline, const char *option, char *buffer,
int bufsize)
{
if (IS_ENABLED(CONFIG_CMDLINE_BOOL))
WARN_ON_ONCE(!builtin_cmdline_added);
return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option,
buffer, bufsize);
}
|
