qrap: Handle case of PATH environment variable being unset

clang-tidy warns that in passing getenv("PATH") to strncpy() we could be
passing a NULL pointer.  While it's unusual for PATH to be unset, it's not
impossible and this would indeed cause getenv() to return NULL.

Handle this case by never recognizing argv[2] as a qemu binary name if
PATH is not set.  This is... no flakier than the detection of whether
it's a binary name already is.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/qrap.c b/qrap.c
index 3138386..a9a0fc1 100644
--- a/qrap.c
+++ b/qrap.c
@@ -173,12 +173,13 @@ int main(int argc, char **argv)
 	char probe_r;
 
 	if (argc >= 3) {
+		const char *path = getenv("PATH");
 		errno = 0;
 		fd = strtol(argv[1], NULL, 0);
-		if (fd >= 3 && fd < INT_MAX && !errno) {
+		if (fd >= 3 && fd < INT_MAX && !errno && path) {
 			char env_path[ARG_MAX + 1], *p, command[ARG_MAX];
 
-			strncpy(env_path, getenv("PATH"), ARG_MAX);
+			strncpy(env_path, path, ARG_MAX);
 			/* cppcheck-suppress strtokCalled */
 			p = strtok(env_path, ":");
 			while (p) {