Fixed compiler errors on ancient Linux distributions

SAP · Oct 8, 2017 · f47c152 · f47c152
1 parent 48c836c
commit f47c152
Showing 1 changed file with 12 additions and 12 deletions.
diff --git a/src/jattach.c b/src/jattach.c
@@ -21,24 +21,25 @@
 #include <sys/stat.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <sys/syscall.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <time.h>
 #include <unistd.h>
 
-#define PATH_MAX 1024
+#define MAX_PATH 1024
 
 
 #ifdef __APPLE__
 
 // macOS has a secure per-user temporary directory
 const char* get_temp_directory() {
-    static char temp_path_storage[PATH_MAX] = {0};
+    static char temp_path_storage[MAX_PATH] = {0};
 
     if (temp_path_storage[0] == 0) {
-        int path_size = confstr(_CS_DARWIN_USER_TEMP_DIR, temp_path_storage, PATH_MAX);
-        if (path_size == 0 || path_size > PATH_MAX) {
+        int path_size = confstr(_CS_DARWIN_USER_TEMP_DIR, temp_path_storage, MAX_PATH);
+        if (path_size == 0 || path_size > MAX_PATH) {
             strcpy(temp_path_storage, "/tmp");
         }
     }
@@ -51,14 +52,12 @@ const char* get_temp_directory() {
     return "/tmp";
 }
 
-int setns(int fd, int nstype);
-
 #endif // __APPLE__
 
 // Check if remote JVM has already opened socket for Dynamic Attach
 static int check_socket(int pid) {
-    char path[PATH_MAX];
-    snprintf(path, PATH_MAX, "%s/.java_pid%d", get_temp_directory(), pid);
+    char path[MAX_PATH];
+    snprintf(path, MAX_PATH, "%s/.java_pid%d", get_temp_directory(), pid);
 
     struct stat stats;
     return stat(path, &stats) == 0 && S_ISSOCK(stats.st_mode);
@@ -67,12 +66,12 @@ static int check_socket(int pid) {
 // Force remote JVM to start Attach listener.
 // HotSpot will start Attach listener in response to SIGQUIT if it sees .attach_pid file
 static int start_attach_mechanism(int pid, int nspid) {
-    char path[PATH_MAX];
-    snprintf(path, PATH_MAX, "/proc/%d/cwd/.attach_pid%d", nspid, nspid);
+    char path[MAX_PATH];
+    snprintf(path, MAX_PATH, "/proc/%d/cwd/.attach_pid%d", nspid, nspid);
 
     int fd = creat(path, 0660);
     if (fd == -1) {
-        snprintf(path, PATH_MAX, "%s/.attach_pid%d", get_temp_directory(), nspid);
+        snprintf(path, MAX_PATH, "%s/.attach_pid%d", get_temp_directory(), nspid);
         fd = creat(path, 0660);
         if (fd == -1) {
             return 0;
@@ -192,7 +191,8 @@ static int enter_mount_ns(int pid) {
         return 1;
     }
 
-    return setns(newns, 0) < 0 ? 0 : 1;
+    // Some ancient Linux distributions do not have setns() function
+    return syscall(__NR_setns, newns, 0) < 0 ? 0 : 1;
 #else
     return 1;
 #endif