Source: netkit-ntalk Version: 0.17-20 Severity: important Tags: patch, ftbfs User: [email protected] Usertags: hurd-amd64 X-Debbugs-Cc: [email protected]
netkit-ntalk fails to build from source on hurd-amd64 because two macros the source relies on are not defined by the Hurd libc headers: Buildd log (hurd-amd64, 0.17-20): https://buildd.debian.org/status/fetch.php?pkg=netkit-ntalk&arch=hurd-amd64&ver=0.17-20&stamp=1783711377&raw=1 talk/get_names.c:55:23: error: 'MAXHOSTNAMELEN' undeclared (first use in this function) 55 | char hostname[MAXHOSTNAMELEN]; The build stops there. One file later, talkd/process.c:122 declares find_user()'s scratch buffer as "char besttty[PATH_MAX]", which does not compile on Hurd either. Root cause: GNU/Hurd has no fixed path limit, so PATH_MAX is not defined. MAXHOSTNAMELEN is a BSD constant that is also absent on Hurd. The patch below replaces the PATH_MAX-sized temporary buffer in talkd/process.c with dynamic allocation. It also supplies MAXHOSTNAMELEN from HOST_NAME_MAX, or from _POSIX_HOST_NAME_MAX when HOST_NAME_MAX is unavailable. No feature or test is disabled. I verified the patch on native GNU/Hurd amd64 running Debian unstable. The unmodified 0.17-20 source reproduced the MAXHOSTNAMELEN build failure. The patch then applied with zero fuzz and zero offset, and dpkg-buildpackage completed successfully, producing talk and talkd. The package defines no autopkgtest or upstream test suite. One thing to flag rather than let you find it in your own build log: on GCC 15 the new strdup(uptr->ut_line) call raises warning: 'strdup' argument 1 declared attribute 'nonstring' [-Wstringop-overread] because ut_line is a fixed-size utmp field with no guaranteed NUL terminator. The strcpy() it replaces read ut_line exactly the same way, so this is a new diagnostic rather than a new unbounded read — but it is new, and it appears on every architecture. If you would prefer the variant without it, sizing besttty as sizeof(uptr->ut_line) + 1 and copying with an explicit terminator removes the PATH_MAX dependency just as well and is a smaller diff. I am happy to send that instead; I went with the allocation because it makes no assumption about the utmp field width. Toolchain stamp: - hurd 1:0.9.git20260527-3+b1 - libc0.3 2.42-17 - gcc-15 15.3.0-1 - binutils 2.46.90.20260712-1 netkit-ntalk is maintained by the Debian QA Group and the netkit collection has no active upstream, so there is nowhere to forward this fix — hence "Forwarded: no" in the DEP-3 header below, and this report rather than an upstream submission. Assisted-by: hurd-collab agent (automated portability triage and fix) Signed-off-by: Federico Bonino <[email protected]> --- netkit-ntalk-hurd.patch --- Description: Replace PATH_MAX buffer with dynamic allocation and add MAXHOSTNAMELEN fallback for GNU/Hurd Source-Version: 0.17-20 Author: Federico Bonino <[email protected]> Forwarded: no Last-Update: 2026-07-28 GNU/Hurd does not define PATH_MAX because it has no fixed path limit. The besttty buffer in talkd/process.c was only used as a temporary scratch area to hold a utmp tty line before copying it to the caller's output buffer; it is now dynamically allocated with strdup, removing the fixed-size PATH_MAX dependency. The MAXHOSTNAMELEN buffer in talk/get_names.c is used for gethostname and the legacy talk wire protocol uses fixed-size fields, so a bounded hostname buffer remains appropriate. Since Hurd does not provide MAXHOSTNAMELEN, provide a conditional fallback to HOST_NAME_MAX (or _POSIX_HOST_NAME_MAX) from <limits.h>, preserving the existing behaviour on BSD/Linux platforms. --- a/talkd/process.c +++ b/talkd/process.c @@ -55,6 +55,7 @@ char rcsid[] = #include <syslog.h> #include <stdio.h> #include <string.h> +#include <stdlib.h> /* #include <paths.h> <---- unused? */ #include <utmp.h> #include "prot_talkd.h" @@ -119,9 +120,12 @@ find_user(const char *name, char *tty) struct utmp *uptr; int found=0, ok=0, ret; time_t best_time = 0, this_time; - char besttty[PATH_MAX]; + char *besttty; - *besttty = 0; + besttty = strdup(""); + if (besttty == NULL) { + return FAILED; + } setutent(); while ((uptr = getutent())!=NULL) { #ifdef USER_PROCESS @@ -135,6 +139,7 @@ find_user(const char *name, char *tty) if (*tty && !strcmp(tty, uptr->ut_line)) { /* asked for a tty, found it */ endutent(); + free(besttty); return SUCCESS; } ret = check_tty_perms(uptr->ut_line, &this_time); @@ -145,11 +150,17 @@ find_user(const char *name, char *tty) found = ok = 1; if (this_time > best_time) { best_time = this_time; - strcpy(besttty, uptr->ut_line); + free(besttty); + besttty = strdup(uptr->ut_line); + if (besttty == NULL) { + endutent(); + return FAILED; + } } } endutent(); strcpy(tty, besttty); + free(besttty); return !found ? NOT_HERE : (!ok ? PERMISSION_DENIED : SUCCESS); } --- a/talk/get_names.c +++ b/talk/get_names.c @@ -39,6 +39,14 @@ char gn_rcsid[] = #include <stdio.h> #include <sys/param.h> +#include <limits.h> +#ifndef MAXHOSTNAMELEN +#ifdef HOST_NAME_MAX +#define MAXHOSTNAMELEN HOST_NAME_MAX +#else +#define MAXHOSTNAMELEN _POSIX_HOST_NAME_MAX +#endif +#endif #include <sys/socket.h> #include <pwd.h> #include <unistd.h>
