| 1 | /* Public domain. */ |
| 2 | /* Adapted from DJB's original cdb-0.75 package */ |
| 3 | |
| 4 | #include <sys/types.h> |
| 5 | #include <sys/stat.h> |
| 6 | #include <sys/mman.h> |
| 7 | #include <unistd.h> |
| 8 | #include <string.h> |
| 9 | #include <errno.h> |
| 10 | #include "cdb.h" |
| 11 | |
| 12 | #ifndef EPROTO |
| 13 | #define EPROTO -15 /* cdb 0.75's default for PROTOless systems */ |
| 14 | #endif |
| 15 | |
| 16 | void cdb_free(struct cdb *c) |
| 17 | { |
| 18 | if (c->map) { |
| 19 | munmap(c->map,c->size); |
| 20 | c->map = 0; |
| 21 | } |
| 22 | } |
| 23 | |
| 24 | void cdb_findstart(struct cdb *c) |
| 25 | { |
| 26 | c->loop = 0; |
| 27 | } |
| 28 | |
| 29 | void cdb_init(struct cdb *c,int fd) |
| 30 | { |
| 31 | struct stat st; |
| 32 | char *x; |
| 33 | |
| 34 | cdb_free(c); |
| 35 | cdb_findstart(c); |
| 36 | c->fd = fd; |
| 37 | |
| 38 | if (fstat(fd,&st) == 0) |
| 39 | if (st.st_size <= 0xffffffff) { |
| 40 | x = mmap(0,st.st_size,PROT_READ,MAP_SHARED,fd,0); |
| 41 | if (x + 1) { |
| 42 | c->size = st.st_size; |
| 43 | c->map = x; |
| 44 | } |
| 45 | } |
| 46 | } |
| 47 | |
| 48 | int cdb_read(struct cdb *c,char *buf,unsigned int len,uint32 pos) |
| 49 | { |
| 50 | if (c->map) { |
| 51 | if ((pos > c->size) || (c->size - pos < len)) goto FORMAT; |
| 52 | memcpy(buf,c->map + pos,len); |
| 53 | } |
| 54 | else { |
| 55 | if (lseek(c->fd,pos,SEEK_SET) == -1) return -1; |
| 56 | /* if (seek_set(c->fd,pos) == -1) return -1; */ |
| 57 | while (len > 0) { |
| 58 | int r; |
| 59 | do |
| 60 | r = read(c->fd,buf,len); |
| 61 | while ((r == -1) && (errno == EINTR)); |
| 62 | if (r == -1) return -1; |
| 63 | if (r == 0) goto FORMAT; |
| 64 | buf += r; |
| 65 | len -= r; |
| 66 | } |
| 67 | } |
| 68 | return 0; |
| 69 | |
| 70 | FORMAT: |
| 71 | errno = EPROTO; |
| 72 | return -1; |
| 73 | } |
| 74 | |
| 75 | static int match(struct cdb *c,char *key,unsigned int len,uint32 pos) |
| 76 | { |
| 77 | char buf[32]; |
| 78 | int n; |
| 79 | |
| 80 | while (len > 0) { |
| 81 | n = sizeof buf; |
| 82 | if (n > len) n = len; |
| 83 | if (cdb_read(c,buf,n,pos) == -1) return -1; |
| 84 | if (memcmp(buf,key,n)) return 0; |
| 85 | pos += n; |
| 86 | key += n; |
| 87 | len -= n; |
| 88 | } |
| 89 | return 1; |
| 90 | } |
| 91 | |
| 92 | int cdb_findnext(struct cdb *c,char *key,unsigned int len) |
| 93 | { |
| 94 | char buf[8]; |
| 95 | uint32 pos; |
| 96 | uint32 u; |
| 97 | |
| 98 | if (!c->loop) { |
| 99 | u = cdb_hash(key,len); |
| 100 | if (cdb_read(c,buf,8,(u << 3) & 2047) == -1) return -1; |
| 101 | uint32_unpack(buf + 4,&c->hslots); |
| 102 | if (!c->hslots) return 0; |
| 103 | uint32_unpack(buf,&c->hpos); |
| 104 | c->khash = u; |
| 105 | u >>= 8; |
| 106 | u %= c->hslots; |
| 107 | u <<= 3; |
| 108 | c->kpos = c->hpos + u; |
| 109 | } |
| 110 | |
| 111 | while (c->loop < c->hslots) { |
| 112 | if (cdb_read(c,buf,8,c->kpos) == -1) return -1; |
| 113 | uint32_unpack(buf + 4,&pos); |
| 114 | if (!pos) return 0; |
| 115 | c->loop += 1; |
| 116 | c->kpos += 8; |
| 117 | if (c->kpos == c->hpos + (c->hslots << 3)) c->kpos = c->hpos; |
| 118 | uint32_unpack(buf,&u); |
| 119 | if (u == c->khash) { |
| 120 | if (cdb_read(c,buf,8,pos) == -1) return -1; |
| 121 | uint32_unpack(buf,&u); |
| 122 | if (u == len) |
| 123 | switch(match(c,key,len,pos + 8)) { |
| 124 | case -1: |
| 125 | return -1; |
| 126 | case 1: |
| 127 | uint32_unpack(buf + 4,&c->dlen); |
| 128 | c->dpos = pos + 8 + len; |
| 129 | return 1; |
| 130 | } |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | return 0; |
| 135 | } |
| 136 | |
| 137 | int cdb_find(struct cdb *c,char *key,unsigned int len) |
| 138 | { |
| 139 | cdb_findstart(c); |
| 140 | return cdb_findnext(c,key,len); |
| 141 | } |