libcamera: process: Misc. cleanup around `execv()`

Firstly, get the number of arguments first, and use that to determine the
size of the allocation instead of retrieving it twice.

Secondly, use `const_cast` instead of a C-style cast when calling `execv()`.

Third, use `size_t` to match the type of `args.size()`.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/src/libcamera/process.cpp b/src/libcamera/process.cpp
index d836fb07..f4e4b004 100644
--- a/src/libcamera/process.cpp
+++ b/src/libcamera/process.cpp
@@ -279,14 +279,15 @@ int Process::start(const std::string &path,
 		if (file && strcmp(file, "syslog"))
 			unsetenv("LIBCAMERA_LOG_FILE");
 
-		const char **argv = new const char *[args.size() + 2];
-		unsigned int len = args.size();
+		const size_t len = args.size();
+		auto argv = std::make_unique<const char *[]>(len + 2);
+
 		argv[0] = path.c_str();
-		for (unsigned int i = 0; i < len; i++)
+		for (size_t i = 0; i < len; i++)
 			argv[i + 1] = args[i].c_str();
 		argv[len + 1] = nullptr;
 
-		execv(path.c_str(), (char **)argv);
+		execv(path.c_str(), const_cast<char **>(argv.get()));
 
 		_exit(EXIT_FAILURE);
 	}