| 1 | /* Test case for gethostbyname_r bug when buffer expansion required. */ |
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| 2 | |
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| 3 | #include <netdb.h> |
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| 4 | #include <arpa/inet.h> |
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| 5 | #include <errno.h> |
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| 6 | #include <string.h> |
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| 7 | #include <stdio.h> |
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| 8 | #include <stdlib.h> |
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| 9 | #include <unistd.h> |
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| 10 | |
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| 11 | int |
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| 12 | main (void) |
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| 13 | { |
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| 14 | const char *host = "www.gnu.org" ; |
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| 15 | |
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| 16 | /* This code approximates the example code in the library manual. */ |
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| 17 | |
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| 18 | struct hostent hostbuf, *hp; |
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| 19 | size_t hstbuflen; |
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| 20 | char *tmphstbuf; |
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| 21 | int res; |
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| 22 | int herr; |
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| 23 | |
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| 24 | hstbuflen = 16; /* Make it way small to ensure ERANGE. */ |
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| 25 | /* Allocate buffer, remember to free it to avoid memory leakage. */ |
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| 26 | tmphstbuf = malloc (size: hstbuflen); |
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| 27 | |
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| 28 | while ((res = gethostbyname_r (name: host, result_buf: &hostbuf, buf: tmphstbuf, buflen: hstbuflen, |
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| 29 | result: &hp, h_errnop: &herr)) == ERANGE) |
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| 30 | { |
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| 31 | /* Enlarge the buffer. */ |
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| 32 | hstbuflen *= 2; |
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| 33 | tmphstbuf = realloc (ptr: tmphstbuf, size: hstbuflen); |
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| 34 | } |
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| 35 | |
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| 36 | if (res != 0 || hp == NULL) |
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| 37 | { |
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| 38 | printf (format: "gethostbyname_r failed: %s (errno: %m)\n" , strerror (errnum: res)); |
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| 39 | |
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| 40 | if (access (name: "/etc/resolv.conf" , R_OK)) |
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| 41 | { |
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| 42 | puts (s: "DNS probably not set up" ); |
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| 43 | return 0; |
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| 44 | } |
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| 45 | |
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| 46 | return 1; |
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| 47 | } |
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| 48 | |
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| 49 | printf (format: "Got: %s %s\n" , hp->h_name, |
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| 50 | inet_ntoa (in: *(struct in_addr *) hp->h_addr)); |
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| 51 | return 0; |
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| 52 | } |
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| 53 | |
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