0.3.0: converge relibc to upstream 0.6.0 + Red Bear patches

tests/waitpid_multiple.c

@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <assert.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "test_helpers.h"
+
+int main(void) {
+    // Spawn three childrens, one with same pgid and two with pgid set to its own
+    // pid, so the exit order is two different pgid, then followed with same pgid
+
+    pid_t pid_samepgid = fork();
+    ERROR_IF(fork, pid_samepgid, == -1);
+
+    if (pid_samepgid == 0) {
+        // child
+        usleep(300000);
+        _Exit(2);
+    }
+    pid_t pid_diffpgids[2];
+    for (int i = 0; i < 2; i++) {
+        pid_diffpgids[i] = fork();
+        ERROR_IF(fork, pid_diffpgids[i], == -1);
+
+        if (pid_diffpgids[i] == 0) {
+            int ret = setpgid(0, 0);
+            ERROR_IF(setpgid, ret, == -1);
+
+            // child
+            usleep((i + 1) * 100000);
+            _Exit(i);
+        }
+    }
+    int status;
+    pid_t wid;
+
+    // First, check that the first different-pgid proc is recognized.
+    wid = waitpid(-1, &status, 0);
+    ERROR_IF(waitpid, wid, == -1);
+    assert(wid == pid_diffpgids[0]);
+    assert(WIFEXITED(status));
+    assert(WEXITSTATUS(status) == 0);
+
+    // Then, check that the longest-waiting proc with the same pgid is properly matched.
+    wid = waitpid(0, &status, 0);
+    ERROR_IF(waitpid, wid, == -1);
+    assert(wid == pid_samepgid);
+    assert(WIFEXITED(status));
+    assert(WEXITSTATUS(status) == 2);
+
+    // Finally, the last different-pgid must have completed.
+    wid = waitpid(-1, &status, WNOHANG);
+    ERROR_IF(waitpid, wid, == -1);
+    assert(wid == pid_diffpgids[1]);
+    assert(WIFEXITED(status));
+    assert(WEXITSTATUS(status) == 1);
+}