svn commit: r336302 - head/usr.sbin/kldxref

[Warner Losh]

Author: imp
Date: Sun Jul 15 05:29:39 2018
New Revision: 336302
URL: https://svnweb.freebsd.org/changeset/base/336302

Log:
  Use EF_SEG_READ_STRING instead of EF_SEG_READ when reading strings.
  
  Normally, we can get away with just reading the 1k buffer for the
  string, since the placement of the data is generally no where near the
  end of the file. However, it's possible that the string is within the
  last 1k of the file, in which case the read will fail, and we'll not
  produce the proper records needed for devmatch to work. By reading
  using EF_SEG_READ_STRING, we automatically work around these problems
  while still retaining safety.
  
  This fix a problem with devmatch where we wouldn't load certain
  modules (like ums). This didn't always happen (my tree didn't exhibit
  it, while nathan's did because his optimization options were more
  agressive).
  
  Reported by: nathanw@

Modified:
  head/usr.sbin/kldxref/kldxref.c

Modified: head/usr.sbin/kldxref/kldxref.c
==============================================================================
--- head/usr.sbin/kldxref/kldxref.c	Sun Jul 15 00:47:06 2018	(r336301)
+++ head/usr.sbin/kldxref/kldxref.c	Sun Jul 15 05:29:39 2018	(r336302)
@@ -420,7 +420,7 @@ parse_entry(struct mod_metadata *md, const char *cval,
 		break;
 	case MDT_PNP_INFO:
 		check(EF_SEG_READ_REL(ef, data, sizeof(pnp), &pnp));
-		check(EF_SEG_READ(ef, (Elf_Off)pnp.descr, sizeof(descr), descr));
+		check(EF_SEG_READ_STRING(ef, (Elf_Off)pnp.descr, sizeof(descr), descr));
 		descr[sizeof(descr) - 1] = '\0';
 		if (dflag) {
 			printf("  pnp info for bus %s format %s %d entries of %d bytes\n",
@@ -510,7 +510,7 @@ parse_entry(struct mod_metadata *md, const char *cval,
 							ptr = *(char **)(walker + elt->pe_offset);
 							buffer[0] = '\0';
 							if (ptr != NULL) {
-								EF_SEG_READ(ef, (Elf_Off)ptr,
+								EF_SEG_READ_STRING(ef, (Elf_Off)ptr,
 								    sizeof(buffer), buffer);
 								buffer[sizeof(buffer) - 1] = '\0';
 							}