tifile.c - plan9port - [fork] Plan 9 from user space
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tifile.c (2592B)
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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 }