1 #include "stdinc.h"
2 #include "dat.h"
3 #include "fns.h"
4 
5 static char vcmagic[] = "venti config\n";
6 
7 enum {
8 	Maxconfig = 8 * 1024,
9 	Maglen = sizeof vcmagic - 1,
10 };
11 
12 int
13 readifile(IFile *f, char *name)
14 {
15 	Part *p;
16 	ZBlock *b;
17 	u8int *z;
18 
19 	p = initpart(name, OREAD);
20 	if(p == nil)
21 		return -1;
22 	b = alloczblock(Maxconfig+1, 1, 0);
23 	if(b == nil){
24 		seterr(EOk, "can't alloc for %s: %R", name);
25 		return -1;
26 	}
27 	if(p->size > PartBlank){
28 		/*
29 		 * this is likely a real venti partition, in which case we're
30 		 * looking for the config file stored as 8k at end of PartBlank.
31 		 */
32 		if(readpart(p, PartBlank-Maxconfig, b->data, Maxconfig) < 0){
33 			seterr(EOk, "can't read %s: %r", name);
34 			freezblock(b);
35 			freepart(p);
36 			return -1;
37 		}
38 		b->data[Maxconfig] = '\0';
39 		if(memcmp(b->data, vcmagic, Maglen) != 0){
40 			seterr(EOk, "bad venti config magic in %s", name);
41 			freezblock(b);
42 			freepart(p);
43 			return -1;
44 		}
45 		/*
46 		 * if we change b->data+b->_size, freezblock
47 		 * will blow an assertion, so don't.
48 		 */
49 		b->data  += Maglen;
50 		b->_size -= Maglen;
51 		b->len   -= Maglen;
52 		z = memchr(b->data, '\0', b->len);
53 		if(z)
54 			b->len = z - b->data;
55 	}else if(p->size > Maxconfig){
56 		seterr(EOk, "config file is too large");
57 		freepart(p);
58 		freezblock(b);
59 		return -1;
60 	}else{
61 		freezblock(b);
62 		b = readfile(name);
63 		if(b == nil){
64 			freepart(p);
65 			return -1;
66 		}
67 	}
68 	freepart(p);
69 	f->name = name;
70 	f->b = b;
71 	f->pos = 0;
72 	return 0;
73 }
74 
75 void
76 freeifile(IFile *f)
77 {
78 	freezblock(f->b);
79 	f->b = nil;
80 	f->pos = 0;
81 }
82 
83 int
84 partifile(IFile *f, Part *part, u64int start, u32int size)
85 {
86 	ZBlock *b;
87 
88 	b = alloczblock(size, 0, part->blocksize);
89 	if(b == nil)
90 		return -1;
91 	if(readpart(part, start, b->data, size) < 0){
92 		seterr(EAdmin, "can't read %s: %r", part->name);
93 		freezblock(b);
94 		return -1;
95 	}
96 	f->name = part->name;
97 	f->b = b;
98 	f->pos = 0;
99 	return 0;
100 }
101 
102 /*
103  * return the next non-blank input line,
104  * stripped of leading white space and with # comments eliminated
105  */
106 char*
107 ifileline(IFile *f)
108 {
109 	char *s, *e, *t;
110 	int c;
111 
112 	for(;;){
113 		s = (char*)&f->b->data[f->pos];
114 		e = memchr(s, '\n', f->b->len - f->pos);
115 		if(e == nil)
116 			return nil;
117 		*e++ = '\0';
118 		f->pos = e - (char*)f->b->data;
119 		t = strchr(s, '#');
120 		if(t != nil)
121 			*t = '\0';
122 		for(; c = *s; s++)
123 			if(c != ' ' && c != '\t' && c != '\r')
124 				return s;
125 	}
126 }
127 
128 int
129 ifilename(IFile *f, char *dst)
130 {
131 	char *s;
132 
133 	s = ifileline(f);
134 	if(s == nil || strlen(s) >= ANameSize)
135 		return -1;
136 	namecp(dst, s);
137 	return 0;
138 }
139 
140 int
141 ifileu32int(IFile *f, u32int *r)
142 {
143 	char *s;
144 
145 	s = ifileline(f);
146 	if(s == nil)
147 		return -1;
148 	return stru32int(s, r);
149 }