add linux dlsym hook

test_so/posix.c

@@ -0,0 +1,79 @@
+
+
+// hook --> 
+
+// open
+
+
+// write
+
+
+// read
+
+
+// close
+
+#define _GNU_SOURCE
+#include <dlfcn.h>
+
+
+#include <stdio.h>
+
+
+
+typedef int (*open_t)(const char *pathname, int flags);
+open_t  open_f = NULL;
+
+typedef ssize_t (*read_t)(int fd, void *buf, size_t count);
+read_t read_f = NULL;
+
+
+typedef ssize_t (*write_t)(int fd, const void *buf, size_t count);
+write_t write_f = NULL;
+
+typedef int (*close_t)(int fd);
+close_t close_f = NULL;
+
+
+int open(const char *pathname, int flags) {
+
+	if (open_f == NULL) {
+		open_f = dlsym(RTLD_NEXT, "open");
+	}
+
+	printf("open .. %s\n", pathname);
+
+	return open_f(pathname, flags);
+}
+
+ssize_t read(int fd, void *buf, size_t count) {
+
+	if (read_f == NULL) {
+		read_f = dlsym(RTLD_NEXT, "read");
+	}
+
+	printf("read ..\n");
+	return read_f(fd, buf, count);
+}
+
+ssize_t write(int fd, const void *buf, size_t count) {
+
+	if (write_f == NULL) {
+		write_f = dlsym(RTLD_NEXT, "write");
+	}
+
+	printf("write ..\n");
+	return write_f(fd, buf, count);
+}
+
+int close(int fd) {
+	if (close_f == NULL) {
+		close_f = dlsym(RTLD_NEXT, "close");
+	}
+
+	printf("close ..\n");
+	return close_f(fd);
+}
+
+
+