diff options
author | Bjørn Mork <bjorn@mork.no> | 2015-05-15 10:20:47 +0200 |
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committer | Bjørn Mork <bjorn@mork.no> | 2015-05-15 10:20:47 +0200 |
commit | 73b16af8feec390afbabd9356d6e5e83c0390838 (patch) | |
tree | 3730020ba2f9caeb9d7815a975af51830b51ce11 /libbb/safe_gethostname.c |
busybox: imported from http://www.busybox.net/downloads/busybox-1.13.3.tar.bz2busybox-1.13.3
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Diffstat (limited to 'libbb/safe_gethostname.c')
-rw-r--r-- | libbb/safe_gethostname.c | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/libbb/safe_gethostname.c b/libbb/safe_gethostname.c new file mode 100644 index 0000000..7407fb7 --- /dev/null +++ b/libbb/safe_gethostname.c @@ -0,0 +1,66 @@ +/* vi: set sw=4 ts=4: */ +/* + * Safe gethostname implementation for busybox + * + * Copyright (C) 2008 Tito Ragusa <farmatito@tiscali.it> + * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. + */ + +/* + * SUSv2 guarantees that "Host names are limited to 255 bytes" + * POSIX.1-2001 guarantees that "Host names (not including the terminating + * null byte) are limited to HOST_NAME_MAX bytes" (64 bytes on my box). + * + * RFC1123 says: + * + * The syntax of a legal Internet host name was specified in RFC-952 + * [DNS:4]. One aspect of host name syntax is hereby changed: the + * restriction on the first character is relaxed to allow either a + * letter or a digit. Host software MUST support this more liberal + * syntax. + * + * Host software MUST handle host names of up to 63 characters and + * SHOULD handle host names of up to 255 characters. + */ + +#include "libbb.h" +#include <sys/utsname.h> + +/* + * On success return the current malloced and NUL terminated hostname. + * On error return malloced and NUL terminated string "?". + * This is an illegal first character for a hostname. + * The returned malloced string must be freed by the caller. + */ +char* FAST_FUNC safe_gethostname(void) +{ + struct utsname uts; + + /* The length of the arrays in a struct utsname is unspecified; + * the fields are terminated by a null byte. + * Note that there is no standard that says that the hostname + * set by sethostname(2) is the same string as the nodename field of the + * struct returned by uname (indeed, some systems allow a 256-byte host- + * name and an 8-byte nodename), but this is true on Linux. The same holds + * for setdomainname(2) and the domainname field. + */ + + /* Uname can fail only if you pass a bad pointer to it. */ + uname(&uts); + return xstrndup(!uts.nodename[0] ? "?" : uts.nodename, sizeof(uts.nodename)); +} + +/* + * On success return the current malloced and NUL terminated domainname. + * On error return malloced and NUL terminated string "?". + * This is an illegal first character for a domainname. + * The returned malloced string must be freed by the caller. + */ +char* FAST_FUNC safe_getdomainname(void) +{ + struct utsname uts; + + uname(&uts); + return xstrndup(!uts.domainname[0] ? "?" : uts.domainname, sizeof(uts.domainname)); +} |