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-rw-r--r--nslookup.c185
1 files changed, 87 insertions, 98 deletions
diff --git a/nslookup.c b/nslookup.c
index 969d0b19b..ffa720174 100644
--- a/nslookup.c
+++ b/nslookup.c
@@ -1,3 +1,4 @@
1/* vi: set sw=4 ts=4: */
1/* 2/*
2 * Mini nslookup implementation for busybox 3 * Mini nslookup implementation for busybox
3 * 4 *
@@ -41,148 +42,136 @@
41 | + find out how the real nslookup gets the default name server 42 | + find out how the real nslookup gets the default name server
42 */ 43 */
43 44
44static const char nslookup_usage[] = 45static const char nslookup_usage[] = "nslookup [HOST]\n\n";
45 "nslookup [HOST]\n\n"
46;
47 46
48 47
49/* I have to see how the real nslookup does this. 48/* I have to see how the real nslookup does this.
50 * I could dig through /etc/resolv.conf, but is there a 49 * I could dig through /etc/resolv.conf, but is there a
51 * better (programatic) way? 50 * better (programatic) way?
52 */ 51 */
53static void 52static void server_fprint(FILE * dst)
54server_fprint(FILE *dst)
55{ 53{
56 fprintf(dst, "Server: %s\n", "something"); 54 fprintf(dst, "Server: %s\n", "something");
57 fprintf(dst, "Address: %s\n\n", "something"); 55 fprintf(dst, "Address: %s\n\n", "something");
58} 56}
59 57
60/* only works for IPv4 */ 58/* only works for IPv4 */
61static int 59static int addr_fprint(char *addr, FILE * dst)
62addr_fprint(char *addr, FILE *dst)
63{ 60{
64 uint8_t split[4]; 61 uint8_t split[4];
65 uint32_t ip; 62 uint32_t ip;
66 uint32_t *x = (uint32_t *) addr; 63 uint32_t *x = (uint32_t *) addr;
67 64
68 ip = ntohl(*x); 65 ip = ntohl(*x);
69 split[0] = (ip & 0xff000000) >> 24; 66 split[0] = (ip & 0xff000000) >> 24;
70 split[1] = (ip & 0x00ff0000) >> 16; 67 split[1] = (ip & 0x00ff0000) >> 16;
71 split[2] = (ip & 0x0000ff00) >> 8; 68 split[2] = (ip & 0x0000ff00) >> 8;
72 split[3] = (ip & 0x000000ff); 69 split[3] = (ip & 0x000000ff);
73 fprintf ( 70 fprintf(dst, "%d.%d.%d.%d", split[0], split[1], split[2], split[3]
74 dst, "%d.%d.%d.%d", 71 );
75 split[0], split[1], split[2], split[3] 72 return 0;
76 );
77 return 0;
78} 73}
79 74
80/* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+ 75/* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+
81 * into a uint32_t 76 * into a uint32_t
82 */ 77 */
83static uint32_t 78static uint32_t str_to_addr(const char *addr)
84str_to_addr(const char *addr)
85{ 79{
86 uint32_t split[4]; 80 uint32_t split[4];
87 uint32_t ip; 81 uint32_t ip;
88 82
89 sscanf(addr, "%d.%d.%d.%d", 83 sscanf(addr, "%d.%d.%d.%d",
90 &split[0], &split[1], &split[2], &split[3]); 84 &split[0], &split[1], &split[2], &split[3]);
91 85
92 /* assuming sscanf worked */ 86 /* assuming sscanf worked */
93 ip = (split[0] << 24) | 87 ip = (split[0] << 24) |
94 (split[1] << 16) | 88 (split[1] << 16) | (split[2] << 8) | (split[3]);
95 (split[2] << 8) |
96 (split[3]);
97 89
98 return htonl(ip); 90 return htonl(ip);
99} 91}
100 92
101/* takes the NULL-terminated array h_addr_list, and 93/* takes the NULL-terminated array h_addr_list, and
102 * prints its contents appropriately 94 * prints its contents appropriately
103 */ 95 */
104static int 96static int addr_list_fprint(char **h_addr_list, FILE * dst)
105addr_list_fprint(char **h_addr_list, FILE *dst)
106{ 97{
107 int i, j; 98 int i, j;
108 char *addr_string = (h_addr_list[1]) 99 char *addr_string = (h_addr_list[1])
109 ? "Addresses" 100 ? "Addresses" : "Address";
110 : "Address"; 101
111 102 fprintf(dst, "%s: ", addr_string);
112 fprintf(dst, "%s: ", addr_string); 103 for (i = 0, j = 0; h_addr_list[i]; i++, j++) {
113 for (i = 0, j = 0; h_addr_list[i]; i++, j++) { 104 addr_fprint(h_addr_list[i], dst);
114 addr_fprint(h_addr_list[i], dst); 105
115 106 /* real nslookup does this */
116 /* real nslookup does this */ 107 if (j == 4) {
117 if (j == 4) { 108 if (h_addr_list[i + 1]) {
118 if (h_addr_list[i+1]) { 109 fprintf(dst, "\n ");
119 fprintf(dst, "\n "); 110 }
120 } 111 j = 0;
121 j = 0; 112 } else {
122 } else { 113 if (h_addr_list[i + 1]) {
123 if (h_addr_list[i+1]) { 114 fprintf(dst, ", ");
124 fprintf(dst, ", "); 115 }
125 } 116 }
126 }
127 117
128 } 118 }
129 fprintf(dst,"\n"); 119 fprintf(dst, "\n");
130 return 0; 120 return 0;
131} 121}
132 122
133/* gethostbyaddr wrapper */ 123/* gethostbyaddr wrapper */
134static struct hostent * 124static struct hostent *gethostbyaddr_wrapper(const char *address)
135gethostbyaddr_wrapper(const char *address)
136{ 125{
137 struct in_addr addr; 126 struct in_addr addr;
138 127
139 addr.s_addr = str_to_addr(address); 128 addr.s_addr = str_to_addr(address);
140 return gethostbyaddr((char *) &addr, 4, AF_INET); /* IPv4 only for now */ 129 return gethostbyaddr((char *) &addr, 4, AF_INET); /* IPv4 only for now */
141} 130}
142 131
143/* print the results as nslookup would */ 132/* print the results as nslookup would */
144static struct hostent * 133static struct hostent *hostent_fprint(struct hostent *host, FILE * dst)
145hostent_fprint(struct hostent *host, FILE *dst)
146{ 134{
147 if (host) { 135 if (host) {
148 fprintf(dst, "Name: %s\n", host->h_name); 136 fprintf(dst, "Name: %s\n", host->h_name);
149 addr_list_fprint(host->h_addr_list, dst); 137 addr_list_fprint(host->h_addr_list, dst);
150 } else { 138 } else {
151 fprintf(dst, "*** %s\n", hstrerror(h_errno)); 139 fprintf(dst, "*** %s\n", hstrerror(h_errno));
152 } 140 }
153 return host; 141 return host;
154} 142}
155 143
156 144
157/* naive function to check whether char *s is an ip address */ 145/* naive function to check whether char *s is an ip address */
158static int 146static int is_ip_address(const char *s)
159is_ip_address(const char *s)
160{ 147{
161 while (*s) { 148 while (*s) {
162 if ((isdigit(*s)) || (*s == '.')) { s++; continue; } 149 if ((isdigit(*s)) || (*s == '.')) {
163 return 0; 150 s++;
164 } 151 continue;
165 return 1; 152 }
153 return 0;
154 }
155 return 1;
166} 156}
167 157
168/* ________________________________________________________________________ */ 158/* ________________________________________________________________________ */
169int 159int nslookup_main(int argc, char **argv)
170nslookup_main(int argc, char **argv)
171{ 160{
172 struct hostent *host; 161 struct hostent *host;
173 162
174 if (argc < 2) { 163 if (argc < 2) {
175 usage(nslookup_usage); 164 usage(nslookup_usage);
176 } 165 }
177 166
178 server_fprint(stdout); 167 server_fprint(stdout);
179 if (is_ip_address(argv[1])) { 168 if (is_ip_address(argv[1])) {
180 host = gethostbyaddr_wrapper(argv[1]); 169 host = gethostbyaddr_wrapper(argv[1]);
181 } else { 170 } else {
182 host = gethostbyname(argv[1]); 171 host = gethostbyname(argv[1]);
183 } 172 }
184 hostent_fprint(host, stdout); 173 hostent_fprint(host, stdout);
185 return 0; 174 return 0;
186} 175}
187 176
188/* $Id: nslookup.c,v 1.3 2000/02/07 05:29:42 erik Exp $ */ 177/* $Id: nslookup.c,v 1.4 2000/02/08 19:58:47 erik Exp $ */