Clarify '-T' help.

Make it clear that the -T option will prevent all checks on the target
executable.

Bug: 27207746
Change-Id: I80888678530ada6d66d9bee203ee34f03b77f880

2 files changed, 10 insertions, 9 deletions

diff --git a/elfparse.c b/elfparse.c
index b2b5891..cd032af 100644
--- a/elfparse.c
+++ b/elfparse.c
@@ -69,19 +69,19 @@ ElfType get_elf_linkage(const char *path)
 			if (is_elf_magic(pHeader)) {
 				if ((pHeader[EI_DATA] == ELFDATA2LSB) &&
 				    (pHeader[EI_CLASS] == ELFCLASS64)) {
-					/* 64 bit little endian */
+					/* 64-bit little endian. */
 					ret = parseElf64(elf_file, pHeader, 1);
 				} else if ((pHeader[EI_DATA] == ELFDATA2MSB) &&
 					  (pHeader[EI_CLASS] == ELFCLASS64)) {
-					/* 64 bit big endian */
+					/* 64-bit big endian. */
 					ret = parseElf64(elf_file, pHeader, 0);
 				} else if ((pHeader[EI_DATA] == ELFDATA2LSB) &&
 					  (pHeader[EI_CLASS] == ELFCLASS32)) {
-					/* 32 bit little endian */
+					/* 32-bit little endian. */
 					ret = parseElf32(elf_file, pHeader, 1);
 				} else if ((pHeader[EI_DATA] == ELFDATA2MSB) &&
 					  (pHeader[EI_CLASS] == ELFCLASS32)) {
-					/* 32 bit big endian */
+					/* 32-bit big endian. */
 					ret = parseElf32(elf_file, pHeader, 0);
 				}
 			} else {
@@ -90,9 +90,9 @@ ElfType get_elf_linkage(const char *path)
 				 * script. We should parse the #! line and
 				 * check the interpreter to guard against
 				 * static interpreters escaping the sandbox.
-				 * As minijail is only called from rootfs
+				 * As Minijail is only called from the rootfs
 				 * it was deemed not necessary to check this.
-				 * So we will just let execve decided if this
+				 * So we will just let execve(2) decide if this
 				 * is valid.
 				 */
 				ret = ELFDYNAMIC;
diff --git a/minijail0.c b/minijail0.c
index f55e0b3..3d648e3 100644
--- a/minijail0.c
+++ b/minijail0.c
@@ -141,8 +141,8 @@ static void usage(const char *progn)
 	       "              E.g., '-S /usr/share/filters/<prog>.$(uname -m)'.\n"
 	       "              Requires -n when not running as root.\n"
 	       "  -t:         Mount tmpfs at /tmp inside chroot.\n"
-	       "  -T <type>:  Assume <program> is a <type> ELF binary.\n"
-	       "              Must be 'static' or 'dynamic'.\n"
+	       "  -T <type>:  Don't access <program> before execve(2), assume <type> ELF binary.\n"
+	       "              <type> must be 'static' or 'dynamic'.\n"
 	       "  -u <user>:  Change uid to <user>.\n"
 	       "  -U          Enter new user namespace (implies -p).\n"
 	       "  -v:         Enter new mount namespace.\n"
@@ -316,7 +316,8 @@ static int parse_args(struct minijail *j, int argc, char *argv[],
 			else if (!strcmp(optarg, "dynamic"))
 				*elftype = ELFDYNAMIC;
 			else {
-				fprintf(stderr, "ELF type must be 'static' or 'dynamic'.\n");
+				fprintf(stderr, "ELF type must be 'static' or "
+						"'dynamic'.\n");
 				exit(1);
 			}
 			break;