Remove last usage of PATH_MAX and ban its future use

Remove a number of pointless checks against PATH_MAX and
add a syntax-check rule to prevent its use in future
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

cfg.mk

@@ -408,6 +408,11 @@ sc_prohibit_VIR_ERR_NO_MEMORY:
 	halt='use virReportOOMError, not V'IR_ERR_NO_MEMORY		\
 	  $(_sc_search_regexp)
 
+sc_prohibit_PATH_MAX:
+	@prohibit='\<P''ATH_MAX\>'				\
+	halt='dynamically allocate paths, do not use P'ATH_MAX	\
+	  $(_sc_search_regexp)
+
 # Use a subshell for each function, to give the optimal warning message.
 include $(srcdir)/Makefile.nonreentrant
 sc_prohibit_nonreentrant:

src/security/virt-aa-helper.c

@@ -473,7 +473,7 @@ valid_name(const char *name)
      * used to subvert the profile */
     const char *bad = " /[]*";
 
-    if (strlen(name) == 0 || strlen(name) > PATH_MAX - 1)
+    if (strlen(name) == 0)
         return -1;
 
     if (strcspn(name, bad) != strlen(name))
@@ -544,7 +544,7 @@ valid_path(const char *path, const bool readonly)
         "/sys/devices/pci"	/* for hostdev pci devices */
     };
 
-    if (path == NULL || strlen(path) > PATH_MAX - 1) {
+    if (path == NULL) {
         vah_error(NULL, 0, _("bad pathname"));
         return -1;
     }

src/storage/storage_backend_scsi.c

@@ -251,7 +251,7 @@ virStorageBackendSCSINewLun(virStoragePoolObjPtr pool,
         goto free_vol;
     }
 
-    if (STREQLEN(devpath, vol->target.path, PATH_MAX) &&
+    if (STREQ(devpath, vol->target.path) &&
         !(STREQ(pool->def->target.path, "/dev") ||
           STREQ(pool->def->target.path, "/dev/"))) {
 

src/xenxs/xen_xm.c

@@ -501,8 +501,6 @@ xenParseXM(virConfPtr conf, int xendConfigVersion,
             /* Extract the source file path*/
             if (!(offset = strchr(head, ',')))
                 goto skipdisk;
-            if ((offset - head) >= (PATH_MAX-1))
-                goto skipdisk;
 
             if (offset == head) {
                 disk->src = NULL; /* No source file given, eg CDROM with no media */

tools/virsh.c

@@ -15542,11 +15542,12 @@ editWriteToTempFile (vshControl *ctl, const char *doc)
     const char *tmpdir;
     int fd;
 
-    ret = vshMalloc(ctl, PATH_MAX);
-
     tmpdir = getenv ("TMPDIR");
     if (!tmpdir) tmpdir = "/tmp";
-    snprintf (ret, PATH_MAX, "%s/virshXXXXXX.xml", tmpdir);
+    if (virAsprintf(&ret, "%s/virshXXXXXX.xml", tmpdir) < 0) {
+        vshError(ctl, "%s", _("out of memory"));
+        return NULL;
+    }
     fd = mkstemps(ret, 4);
     if (fd == -1) {
         vshError(ctl, _("mkstemps: failed to create temporary file: %s"),