diff options
Diffstat (limited to 'src/basic/hostname-util.c')
| -rw-r--r-- | src/basic/hostname-util.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/basic/hostname-util.c b/src/basic/hostname-util.c new file mode 100644 index 0000000000..e336f269fa --- /dev/null +++ b/src/basic/hostname-util.c @@ -0,0 +1,193 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2015 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <sys/utsname.h> +#include <ctype.h> + +#include "util.h" +#include "hostname-util.h" + +bool hostname_is_set(void) { + struct utsname u; + + assert_se(uname(&u) >= 0); + + if (isempty(u.nodename)) + return false; + + /* This is the built-in kernel default host name */ + if (streq(u.nodename, "(none)")) + return false; + + return true; +} + +char* gethostname_malloc(void) { + struct utsname u; + + assert_se(uname(&u) >= 0); + + if (isempty(u.nodename) || streq(u.nodename, "(none)")) + return strdup(u.sysname); + + return strdup(u.nodename); +} + +static bool hostname_valid_char(char c) { + return + (c >= 'a' && c <= 'z') || + (c >= 'A' && c <= 'Z') || + (c >= '0' && c <= '9') || + c == '-' || + c == '_' || + c == '.'; +} + +bool hostname_is_valid(const char *s) { + const char *p; + bool dot; + + if (isempty(s)) + return false; + + /* Doesn't accept empty hostnames, hostnames with trailing or + * leading dots, and hostnames with multiple dots in a + * sequence. Also ensures that the length stays below + * HOST_NAME_MAX. */ + + for (p = s, dot = true; *p; p++) { + if (*p == '.') { + if (dot) + return false; + + dot = true; + } else { + if (!hostname_valid_char(*p)) + return false; + + dot = false; + } + } + + if (dot) + return false; + + if (p-s > HOST_NAME_MAX) + return false; + + return true; +} + +char* hostname_cleanup(char *s, bool lowercase) { + char *p, *d; + bool dot; + + assert(s); + + for (p = s, d = s, dot = true; *p; p++) { + if (*p == '.') { + if (dot) + continue; + + *(d++) = '.'; + dot = true; + } else if (hostname_valid_char(*p)) { + *(d++) = lowercase ? tolower(*p) : *p; + dot = false; + } + + } + + if (dot && d > s) + d[-1] = 0; + else + *d = 0; + + strshorten(s, HOST_NAME_MAX); + + return s; +} + +bool is_localhost(const char *hostname) { + assert(hostname); + + /* This tries to identify local host and domain names + * described in RFC6761 plus the redhatism of .localdomain */ + + return streq(hostname, "localhost") || + streq(hostname, "localhost.") || + streq(hostname, "localdomain.") || + streq(hostname, "localdomain") || + endswith(hostname, ".localhost") || + endswith(hostname, ".localhost.") || + endswith(hostname, ".localdomain") || + endswith(hostname, ".localdomain."); +} + +int sethostname_idempotent(const char *s) { + char buf[HOST_NAME_MAX + 1] = {}; + + assert(s); + + if (gethostname(buf, sizeof(buf)) < 0) + return -errno; + + if (streq(buf, s)) + return 0; + + if (sethostname(s, strlen(s)) < 0) + return -errno; + + return 1; +} + +int read_hostname_config(const char *path, char **hostname) { + _cleanup_fclose_ FILE *f = NULL; + char l[LINE_MAX]; + char *name = NULL; + + assert(path); + assert(hostname); + + f = fopen(path, "re"); + if (!f) + return -errno; + + /* may have comments, ignore them */ + FOREACH_LINE(l, f, return -errno) { + truncate_nl(l); + if (l[0] != '\0' && l[0] != '#') { + /* found line with value */ + name = hostname_cleanup(l, false); + name = strdup(name); + if (!name) + return -ENOMEM; + break; + } + } + + if (!name) + /* no non-empty line found */ + return -ENOENT; + + *hostname = name; + return 0; +} |