1 INSTALLATION INSTRUCTIONS:
7 This will not install the documentation, which is shipped as
8 pre-prepared HTML and PostScript as well as debiandoc-sgml source.
9 Put that (spec.html/ and spec.ps) where you will.
15 * md5sum (GNU textutils; alternatively, Colin Plumb's, as shipped with
16 Debian in the `dpkg' package) - used during build only
18 * GCC is preferred but other compilers ought to work (though
19 no portability testing has yet been done). ANSI C only.
20 ints must be at least 32 bits.
21 * A sensible `cat' which notices write errors (ie not SunOS4, BSD 4.3,
22 or many others. GNU textutils has one. NB that this `cat' is used
23 at runtime and must be first on the system default PATH, so probably
25 * GNU m4 } if you don't want to change those bits of source
26 * GNU flex } you can do without these
30 * [v]snprintf - a real version, not just [v]sprintf with a wrapper
31 that throws the argument away.
36 * memcpy, memset, memcpy;
37 * realloc(0,size) must work and be equivalent to malloc(size).
38 * free(0) must work and do nothing
39 * <stdarg.h> (not varargs) and v[sf][n]printf.
43 * setreuid(2), getreuid(2), getgroups(2), initgroups(3), with
44 the ability for root to (a) swap euid and ruid and
45 (b) give away all privilege by calling setreuid(ruid,ruid)
47 * wait3 and waitpid, <wait.h> with WNOHANG, WIFSIGNALED,
48 WIFEXITEED, WTERMSIG, WEXITSTATUS and WCOREDUMP.
49 * gid_t, uid_t, pid_t.
50 * Unix-domain (AF_UNIX) stream sockets, for use with:
51 * BSD sockets - socket(), bind(), listen(), accept(), connect();
53 * lstat(2) (though stat(2) will be safe on systems without symlinks,
54 if you say -Dlstat=stat).
56 * creating using pipe(2) and mkfifo(2);
57 * proper interaction between open(O_RDWR), open(O_RDONLY),
58 open(O_WRONLY), close(), dup2, EPIPE, SIGPIPE, &c.
59 (ie, opening pipes with O_RDWR never blocks; EPIPE happens
60 if you write with no readers; EOF happens if you read with
61 no buffered data and writers);
62 * POSIX signal handling - sigaction(2), sigprocmask(2), sigsuspend(2);
63 * POSIX sessions - setsid(2) (for -daemon flag).
65 To format the documentation:
67 * debiandoc-sgml, and hence sp (aka nsgmls) and sgmlspm.
68 * For PostScript output, Lout and possibly psutils.
70 For debugging version (./configure --enable-debug):
72 * initgroups(3) must use setgroups(2) and dynamic
73 linking must allow overriding setgroups(2) for initgroups(3);
77 For information about uservd's exit status, see uservd(8).
79 The daemon's per-request children will note the success level of its
80 request in its exit status. This will not usually be logged unless it
81 is higher than those listed below; they are presented here for
82 completeness and as programming documentation.
84 2 - The connection was just an internal version check.
86 4 - The client requested that the service be disconnected. This
87 includes normal termination, which is achieved by having the
88 server tell the client that the service has completed and waiting
89 for the client to tell it to disconnect.
91 8 - The client closed its end of the socket when this would not
92 usually have been expected, causing an EPIPE or unexpected EOF in
93 the server. This is not an error condition - it can happen, for
94 example, if the client receives a fatal signal of some kind from
95 its execution environment (eg its controlling terminal).
97 10 - The per-request child wishes the server to check whether it is
100 12 - The service failed onm the service side in an expected and
101 controlled manner, for example because it was rejected in the
104 16 - A fatal system call failure or other general error occurred,
105 which ought not to have happened at all, barring system resource
108 20 - The client sent invalid data to the server, after the client
109 dropped all its system privilege. On some systems this can be
110 caused by a malicious calling user.
112 SIGABRT/SIGIOT - The client sent invalid data to the server before it
113 dropped all its system privileges, or some other unexpected
114 internal error occurred. This can also occur if an attempt to
115 block signals using sigprocmask fails.
117 0-3,5-7,9,11,13-15,17-19 are not currently used by normal children.
119 REENTRANCY IN THE LIBC:
121 We assume, both in the client and server, that it is safe to use one
122 stdio stream in a signal handler which interrupts use of a _different_
123 stdio stream in another. We make sure using setvbuf that we have
124 pre-allocated buffers so that stdio doesn't need to use malloc() when
125 we actually read or write. stdio had better not do anything else
128 Furthermore, we assume that it is safe to use syslog in a signal
129 handler which has interrupted a stdio operation (but we don't require
130 that it be safe to invoke when the signal has interrupted a call to
131 malloc, unless stdio makes gratuitous mallocs). openlog will already
132 have been called (but syslog will not necessarily have been called).
134 We assume that strerror is completely reentrant.
138 * `function declaration isn't a prototype'
140 One some systems (at least some versions of NetBSD, for example),
141 the SIG_IGN and SIG_DFL macros contain function declarations (as part
142 of a typecast, presumably) which are not prototypes. The warning
143 options that are used by default if the configure script detects that
144 you're using a good GCC then cause the compilation to fail. You must
147 instead of just `make', thus suppressing warnings.
149 The bug is actually in your system header files, for not specifying
150 the number and types of arguments to signal handler functions when
151 they cast in the SIG_IGN and SIG_DFL macros.
155 If you run configure with --enable-debug, a debugging version will be
156 built. This will look in the current directory (the build directory)
157 for the base of various things, including the IPC area (which you must
158 therefore construct yourself). The debugging version will produce
159 extra output at various points. It will not attempt to call
160 setgroups(), instead just checking that the groups list is right, so
161 it will work non-setuid if the daemon is invoked as the service user.
162 The daemon won't fork for each request; instead, it will handle a
163 single request and exit.
165 There may be other changes. Consult the code for details. Making the
166 debugging version of the client or daemon setuid root is probably a
167 bad idea. They may not work if they are run as different users.
172 This file, INSTALL, contains installation instructions and other
176 Copyright (C)1996-2000 Ian Jackson <ian@davenant.greenend.org.uk>.
177 Copyright (C)2000 Ben Harris <bjh21@cam.ac.uk>
179 userv is free software; you can redistribute it and/or modify it under
180 the terms of the GNU General Public License as published by the Free
181 Software Foundation; either version 2 of the License, or (at your
182 option) any later version.
184 This program is distributed in the hope that it will be useful, but
185 WITHOUT ANY WARRANTY; without even the implied warranty of
186 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
187 General Public License for more details.
189 You should have received a copy of the GNU General Public License
190 along with userv as the file COPYING; if not, email me at the address
191 above or write to the Free Software Foundation, 59 Temple Place -
192 Suite 330, Boston, MA 02111-1307, USA.