shadow: FTBFS on hurd-i386 (for review)

[Svante Signell <svante.signell@gmail.com>]

Source: shadow
Version: 4.2-2
Severity: important
Tags: patch
User: debian-hurd@lists.debian.org
Usertags: hurd

Hi,

Currently shadow fails to build from source due to a usage of PATH_MAX,
which is not defined on GNU/Hurd. The attached patch solved this problem
by dynamically allocating space for the string proc_dir_name in files
src/procuidmap.c and src/procgidmap.c and freeing it when not needed any
longer.

Question:
This feature seems to be new:
The new{u,g]idmap sets /proc/[pid]/{u,g}id_map based on it's command
line arguments and the {u,g}ids allowed in /etc/sub{u,g}id.

I can see these entries on GNU/Linux. Will this work on Hurd too or
should the build/installation of them be disabled?

Index: shadow-4.2/src/newuidmap.c
===================================================================
--- shadow-4.2.orig/src/newuidmap.c
+++ shadow-4.2/src/newuidmap.c
@@ -94,7 +94,7 @@ void usage(void)
  */
 int main(int argc, char **argv)
 {
-	char proc_dir_name[PATH_MAX];
+	char *proc_dir_name = NULL;
 	char *target_str;
 	pid_t target, parent;
 	int proc_dir_fd;
@@ -103,6 +103,7 @@ int main(int argc, char **argv)
 	struct stat st;
 	struct passwd *pw;
 	int written;
+	size_t len;
 
 	Prog = Basename (argv[0]);
 
@@ -120,14 +121,23 @@ int main(int argc, char **argv)
 	if (!get_pid(target_str, &target))
 		usage();
 
-	written = snprintf(proc_dir_name, sizeof(proc_dir_name), "/proc/%u/",
+	len = 6 + 10 + 1 + 1;
+	proc_dir_name = malloc(len);
+	if (proc_dir_name == NULL)
+	  {
+	    fprintf(stderr, "%s: malloc failed: %s\n", 
+			Prog, strerror(errno));
+	    return EXIT_FAILURE;
+	  }
+	written = snprintf(proc_dir_name, len, "/proc/%u/",
 		target);
-	if ((written <= 0) || (written >= sizeof(proc_dir_name))) {
+	if ((written <= 0) || (written >= len)) {
 		fprintf(stderr, "%s: snprintf of proc path failed: %s\n",
 			Prog, strerror(errno));
 	}
 
 	proc_dir_fd = open(proc_dir_name, O_DIRECTORY);
+	free (proc_dir_name);
 	if (proc_dir_fd < 0) {
 		fprintf(stderr, _("%s: Could not open proc directory for target %u\n"),
 			Prog, target);