Commit | Line | Data |
---|---|---|
97873a3d | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e44c22f6 PA |
2 | /* -*- linux-c -*- ------------------------------------------------------- * |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright 2007 rPath, Inc. - All Rights Reserved | |
6 | * | |
e44c22f6 PA |
7 | * ----------------------------------------------------------------------- */ |
8 | ||
9 | /* | |
e44c22f6 PA |
10 | * Simple command-line parser for early boot. |
11 | */ | |
12 | ||
13 | #include "boot.h" | |
14 | ||
15 | static inline int myisspace(u8 c) | |
16 | { | |
17 | return c <= ' '; /* Close enough approximation */ | |
18 | } | |
19 | ||
20 | /* | |
21 | * Find a non-boolean option, that is, "option=argument". In accordance | |
22 | * with standard Linux practice, if this option is repeated, this returns | |
23 | * the last instance on the command line. | |
24 | * | |
25 | * Returns the length of the argument (regardless of if it was | |
26 | * truncated to fit in the buffer), or -1 on not found. | |
27 | */ | |
3db07e70 | 28 | int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *buffer, int bufsize) |
e44c22f6 | 29 | { |
e44c22f6 PA |
30 | addr_t cptr; |
31 | char c; | |
32 | int len = -1; | |
33 | const char *opptr = NULL; | |
34 | char *bufptr = buffer; | |
35 | enum { | |
36 | st_wordstart, /* Start of word/after whitespace */ | |
37 | st_wordcmp, /* Comparing this word */ | |
38 | st_wordskip, /* Miscompare, skip */ | |
39 | st_bufcpy /* Copying this to buffer */ | |
40 | } state = st_wordstart; | |
41 | ||
16a4baa6 YL |
42 | if (!cmdline_ptr) |
43 | return -1; /* No command line */ | |
e44c22f6 PA |
44 | |
45 | cptr = cmdline_ptr & 0xf; | |
46 | set_fs(cmdline_ptr >> 4); | |
47 | ||
48 | while (cptr < 0x10000 && (c = rdfs8(cptr++))) { | |
49 | switch (state) { | |
50 | case st_wordstart: | |
51 | if (myisspace(c)) | |
52 | break; | |
53 | ||
54 | /* else */ | |
55 | state = st_wordcmp; | |
56 | opptr = option; | |
df561f66 | 57 | fallthrough; |
e44c22f6 PA |
58 | |
59 | case st_wordcmp: | |
60 | if (c == '=' && !*opptr) { | |
61 | len = 0; | |
62 | bufptr = buffer; | |
63 | state = st_bufcpy; | |
64 | } else if (myisspace(c)) { | |
65 | state = st_wordstart; | |
66 | } else if (c != *opptr++) { | |
67 | state = st_wordskip; | |
68 | } | |
69 | break; | |
70 | ||
71 | case st_wordskip: | |
72 | if (myisspace(c)) | |
73 | state = st_wordstart; | |
74 | break; | |
75 | ||
76 | case st_bufcpy: | |
77 | if (myisspace(c)) { | |
78 | state = st_wordstart; | |
79 | } else { | |
80 | if (len < bufsize-1) | |
81 | *bufptr++ = c; | |
82 | len++; | |
83 | } | |
84 | break; | |
85 | } | |
86 | } | |
87 | ||
88 | if (bufsize) | |
89 | *bufptr = '\0'; | |
90 | ||
91 | return len; | |
92 | } | |
32d0b989 | 93 | |
94 | /* | |
95 | * Find a boolean option (like quiet,noapic,nosmp....) | |
96 | * | |
97 | * Returns the position of that option (starts counting with 1) | |
98 | * or 0 on not found | |
99 | */ | |
3db07e70 | 100 | int __cmdline_find_option_bool(unsigned long cmdline_ptr, const char *option) |
32d0b989 | 101 | { |
32d0b989 | 102 | addr_t cptr; |
103 | char c; | |
70d8abf5 | 104 | int pos = 0, wstart = 0; |
32d0b989 | 105 | const char *opptr = NULL; |
106 | enum { | |
107 | st_wordstart, /* Start of word/after whitespace */ | |
108 | st_wordcmp, /* Comparing this word */ | |
109 | st_wordskip, /* Miscompare, skip */ | |
110 | } state = st_wordstart; | |
111 | ||
16a4baa6 YL |
112 | if (!cmdline_ptr) |
113 | return -1; /* No command line */ | |
32d0b989 | 114 | |
115 | cptr = cmdline_ptr & 0xf; | |
116 | set_fs(cmdline_ptr >> 4); | |
117 | ||
118 | while (cptr < 0x10000) { | |
119 | c = rdfs8(cptr++); | |
120 | pos++; | |
121 | ||
122 | switch (state) { | |
123 | case st_wordstart: | |
124 | if (!c) | |
125 | return 0; | |
126 | else if (myisspace(c)) | |
127 | break; | |
128 | ||
129 | state = st_wordcmp; | |
130 | opptr = option; | |
131 | wstart = pos; | |
df561f66 | 132 | fallthrough; |
32d0b989 | 133 | |
134 | case st_wordcmp: | |
135 | if (!*opptr) | |
136 | if (!c || myisspace(c)) | |
137 | return wstart; | |
138 | else | |
139 | state = st_wordskip; | |
140 | else if (!c) | |
141 | return 0; | |
142 | else if (c != *opptr++) | |
143 | state = st_wordskip; | |
144 | break; | |
145 | ||
146 | case st_wordskip: | |
147 | if (!c) | |
148 | return 0; | |
149 | else if (myisspace(c)) | |
150 | state = st_wordstart; | |
151 | break; | |
152 | } | |
153 | } | |
154 | ||
155 | return 0; /* Buffer overrun */ | |
156 | } |