1 files changed, 42 insertions, 0 deletions
diff --git a/how-to-update-process.c b/how-to-update-process.c
new file mode 100644
index 0000000..6328ecf
--- /dev/null
+++ b/how-to-update-process.c
@@ -0,0 +1,42 @@
+#include <sys/auxv.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+static const char *text = "Change this text and recompile while the process is running";
+
+
+int
+main(int argc, char *argv[])
+{
+	uintptr_t exe_addr = (uintptr_t)getauxval(AT_EXECFN);
+	const char *exe;
+
+	if (!exe_addr) {
+		fprintf(stderr, "%s\n", "Sorry, AT_EXECFN not found, would have to use /proc/self/exe, which is out of scope");
+		/* by the way, if you just exec into /proc/self/exe
+		 * you restart the process, to the same version as
+		 * running even if it has been replaced (define
+		 * RESTART to try it out) */
+		return 1;
+	}
+	exe = (void *)exe_addr; /* beware, this might be a relative path */
+
+	if (argc != 2 || strcmp(argv[1], text))
+		printf("%s\n", text);
+
+	unlink(exe);
+
+	for (;;) {
+		sleep(1);
+#ifdef RESTART
+		execlp("/proc/self/exe", argv[0], text, NULL);
+		abort();
+#else
+		execlp(exe, argv[0], text, NULL);
+#endif
+	}
+}