ifile.c (2592B)
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 }