1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /* -*- linux-c -*- ------------------------------------------------------- *
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Copyright (C) 1991, 1992 Linus Torvalds
5*4882a593Smuzhiyun * Copyright 2007 rPath, Inc. - All Rights Reserved
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * ----------------------------------------------------------------------- */
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun /*
10*4882a593Smuzhiyun * Simple command-line parser for early boot.
11*4882a593Smuzhiyun */
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #include "boot.h"
14*4882a593Smuzhiyun
myisspace(u8 c)15*4882a593Smuzhiyun static inline int myisspace(u8 c)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun return c <= ' '; /* Close enough approximation */
18*4882a593Smuzhiyun }
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun /*
21*4882a593Smuzhiyun * Find a non-boolean option, that is, "option=argument". In accordance
22*4882a593Smuzhiyun * with standard Linux practice, if this option is repeated, this returns
23*4882a593Smuzhiyun * the last instance on the command line.
24*4882a593Smuzhiyun *
25*4882a593Smuzhiyun * Returns the length of the argument (regardless of if it was
26*4882a593Smuzhiyun * truncated to fit in the buffer), or -1 on not found.
27*4882a593Smuzhiyun */
__cmdline_find_option(unsigned long cmdline_ptr,const char * option,char * buffer,int bufsize)28*4882a593Smuzhiyun int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *buffer, int bufsize)
29*4882a593Smuzhiyun {
30*4882a593Smuzhiyun addr_t cptr;
31*4882a593Smuzhiyun char c;
32*4882a593Smuzhiyun int len = -1;
33*4882a593Smuzhiyun const char *opptr = NULL;
34*4882a593Smuzhiyun char *bufptr = buffer;
35*4882a593Smuzhiyun enum {
36*4882a593Smuzhiyun st_wordstart, /* Start of word/after whitespace */
37*4882a593Smuzhiyun st_wordcmp, /* Comparing this word */
38*4882a593Smuzhiyun st_wordskip, /* Miscompare, skip */
39*4882a593Smuzhiyun st_bufcpy /* Copying this to buffer */
40*4882a593Smuzhiyun } state = st_wordstart;
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun if (!cmdline_ptr)
43*4882a593Smuzhiyun return -1; /* No command line */
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun cptr = cmdline_ptr & 0xf;
46*4882a593Smuzhiyun set_fs(cmdline_ptr >> 4);
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun while (cptr < 0x10000 && (c = rdfs8(cptr++))) {
49*4882a593Smuzhiyun switch (state) {
50*4882a593Smuzhiyun case st_wordstart:
51*4882a593Smuzhiyun if (myisspace(c))
52*4882a593Smuzhiyun break;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun /* else */
55*4882a593Smuzhiyun state = st_wordcmp;
56*4882a593Smuzhiyun opptr = option;
57*4882a593Smuzhiyun fallthrough;
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun case st_wordcmp:
60*4882a593Smuzhiyun if (c == '=' && !*opptr) {
61*4882a593Smuzhiyun len = 0;
62*4882a593Smuzhiyun bufptr = buffer;
63*4882a593Smuzhiyun state = st_bufcpy;
64*4882a593Smuzhiyun } else if (myisspace(c)) {
65*4882a593Smuzhiyun state = st_wordstart;
66*4882a593Smuzhiyun } else if (c != *opptr++) {
67*4882a593Smuzhiyun state = st_wordskip;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun break;
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun case st_wordskip:
72*4882a593Smuzhiyun if (myisspace(c))
73*4882a593Smuzhiyun state = st_wordstart;
74*4882a593Smuzhiyun break;
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun case st_bufcpy:
77*4882a593Smuzhiyun if (myisspace(c)) {
78*4882a593Smuzhiyun state = st_wordstart;
79*4882a593Smuzhiyun } else {
80*4882a593Smuzhiyun if (len < bufsize-1)
81*4882a593Smuzhiyun *bufptr++ = c;
82*4882a593Smuzhiyun len++;
83*4882a593Smuzhiyun }
84*4882a593Smuzhiyun break;
85*4882a593Smuzhiyun }
86*4882a593Smuzhiyun }
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun if (bufsize)
89*4882a593Smuzhiyun *bufptr = '\0';
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun return len;
92*4882a593Smuzhiyun }
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun /*
95*4882a593Smuzhiyun * Find a boolean option (like quiet,noapic,nosmp....)
96*4882a593Smuzhiyun *
97*4882a593Smuzhiyun * Returns the position of that option (starts counting with 1)
98*4882a593Smuzhiyun * or 0 on not found
99*4882a593Smuzhiyun */
__cmdline_find_option_bool(unsigned long cmdline_ptr,const char * option)100*4882a593Smuzhiyun int __cmdline_find_option_bool(unsigned long cmdline_ptr, const char *option)
101*4882a593Smuzhiyun {
102*4882a593Smuzhiyun addr_t cptr;
103*4882a593Smuzhiyun char c;
104*4882a593Smuzhiyun int pos = 0, wstart = 0;
105*4882a593Smuzhiyun const char *opptr = NULL;
106*4882a593Smuzhiyun enum {
107*4882a593Smuzhiyun st_wordstart, /* Start of word/after whitespace */
108*4882a593Smuzhiyun st_wordcmp, /* Comparing this word */
109*4882a593Smuzhiyun st_wordskip, /* Miscompare, skip */
110*4882a593Smuzhiyun } state = st_wordstart;
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun if (!cmdline_ptr)
113*4882a593Smuzhiyun return -1; /* No command line */
114*4882a593Smuzhiyun
115*4882a593Smuzhiyun cptr = cmdline_ptr & 0xf;
116*4882a593Smuzhiyun set_fs(cmdline_ptr >> 4);
117*4882a593Smuzhiyun
118*4882a593Smuzhiyun while (cptr < 0x10000) {
119*4882a593Smuzhiyun c = rdfs8(cptr++);
120*4882a593Smuzhiyun pos++;
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun switch (state) {
123*4882a593Smuzhiyun case st_wordstart:
124*4882a593Smuzhiyun if (!c)
125*4882a593Smuzhiyun return 0;
126*4882a593Smuzhiyun else if (myisspace(c))
127*4882a593Smuzhiyun break;
128*4882a593Smuzhiyun
129*4882a593Smuzhiyun state = st_wordcmp;
130*4882a593Smuzhiyun opptr = option;
131*4882a593Smuzhiyun wstart = pos;
132*4882a593Smuzhiyun fallthrough;
133*4882a593Smuzhiyun
134*4882a593Smuzhiyun case st_wordcmp:
135*4882a593Smuzhiyun if (!*opptr)
136*4882a593Smuzhiyun if (!c || myisspace(c))
137*4882a593Smuzhiyun return wstart;
138*4882a593Smuzhiyun else
139*4882a593Smuzhiyun state = st_wordskip;
140*4882a593Smuzhiyun else if (!c)
141*4882a593Smuzhiyun return 0;
142*4882a593Smuzhiyun else if (c != *opptr++)
143*4882a593Smuzhiyun state = st_wordskip;
144*4882a593Smuzhiyun break;
145*4882a593Smuzhiyun
146*4882a593Smuzhiyun case st_wordskip:
147*4882a593Smuzhiyun if (!c)
148*4882a593Smuzhiyun return 0;
149*4882a593Smuzhiyun else if (myisspace(c))
150*4882a593Smuzhiyun state = st_wordstart;
151*4882a593Smuzhiyun break;
152*4882a593Smuzhiyun }
153*4882a593Smuzhiyun }
154*4882a593Smuzhiyun
155*4882a593Smuzhiyun return 0; /* Buffer overrun */
156*4882a593Smuzhiyun }
157