test: add more cases for copyFile

user/permtest.c

@@ -0,0 +1,157 @@
+#include "ulib.h"
+#include "fs.h"
+
+/*
+ * Real ring-3 proof of chmod(2) + real owner rwx permission bits (fs.h's
+ * fsModeOwner*), enforced at the two real choke points this fala added:
+ * resolveOpen (vfs.c) refuses to open an existing file for writing without
+ * fsModeOwnerWrite, and jobctlSpawn/loadImageByPath (jobctl.c/syscall.c)
+ * refuse to spawn a file without fsModeOwnerExec. Fully synchronous like
+ * rmtest.c/timetest.c/nicetest.c: no injected keystrokes, no shared shell
+ * channel, so there is no scheduling-timing race to flake on regardless of
+ * host load.
+ */
+
+static int copyFile(const char* srcPath, const char* dstPath)
+{
+    int src = (int)userOpen(srcPath, oReadOnly);
+    if (src < 0)
+        return -1;
+    int dst = (int)userOpen(dstPath, oReadWrite | oCreate | oTrunc);
+    if (dst < 0) {
+        userClose(src);
+        return -1;
+    }
+
+    char buf[512];
+    long got;
+    while ((got = userRead(src, buf, sizeof(buf))) > 0) {
+        if (userWrite(dst, buf, (unsigned long)got) != got) {
+            userClose(src);
+            userClose(dst);
+            return -1;
+        }
+    }
+    userClose(src);
+    userClose(dst);
+    return got < 0 ? -1 : 0;
+}
+
+int main(void)
+{
+    print("permtest: start, pid=");
+    printDec(userGetpid());
+    print("\n");
+
+    /* --- write permission: a fresh tmpfs file starts at fsModeDefaultFile
+       (0644, owner-writable); chmod to 0444 makes a SUBSEQUENT open-for-
+       write fail while reads keep working, and chmod back restores write
+       access immediately -- real Unix only checks permission at open()
+       time, never re-checks an fd already held. --- */
+    if (userMkdir("/tmp/permd") != 0) {
+        print("permtest: FAIL mkdir /tmp/permd\n");
+        return 1;
+    }
+
+    int fd = (int)userOpen("/tmp/permd/data.txt", oReadWrite | oCreate);
+    if (fd < 0) {
+        print("permtest: FAIL create data.txt\n");
+        return 1;
+    }
+    if (userWrite(fd, "hi", 2) != 2) {
+        print("permtest: FAIL initial write\n");
+        return 1;
+    }
+    userClose(fd);
+
+    FbStat st;
+    if (userStat("/tmp/permd/data.txt", &st) != 0 || st.mode != 0644) {
+        print("permtest: FAIL default mode not 0644\n");
+        return 1;
+    }
+    print("permtest: default-mode-ok\n");
+
+    if (userChmod("/tmp/permd/data.txt", 0444) != 0) {
+        print("permtest: FAIL chmod to read-only\n");
+        return 1;
+    }
+    if (userStat("/tmp/permd/data.txt", &st) != 0 || st.mode != 0444) {
+        print("permtest: FAIL stat after chmod 0444\n");
+        return 1;
+    }
+    if (userOpen("/tmp/permd/data.txt", oWriteOnly) >= 0) {
+        print("permtest: FAIL write-only open succeeded on a read-only file\n");
+        return 1;
+    }
+    int rfd = (int)userOpen("/tmp/permd/data.txt", oReadOnly);
+    if (rfd < 0) {
+        print("permtest: FAIL read-only open failed on a readable file\n");
+        return 1;
+    }
+    char rdbuf[4];
+    if (userRead(rfd, rdbuf, 2) != 2) {
+        print("permtest: FAIL read from read-only file\n");
+        return 1;
+    }
+    userClose(rfd);
+    print("permtest: write-denied-ok\n");
+
+    if (userChmod("/tmp/permd/data.txt", 0644) != 0) {
+        print("permtest: FAIL chmod back to 0644\n");
+        return 1;
+    }
+    int wfd = (int)userOpen("/tmp/permd/data.txt", oWriteOnly | oAppend);
+    if (wfd < 0) {
+        print("permtest: FAIL write open failed after chmod restored write bit\n");
+        return 1;
+    }
+    if (userWrite(wfd, "!", 1) != 1) {
+        print("permtest: FAIL write after chmod restored\n");
+        return 1;
+    }
+    userClose(wfd);
+    print("permtest: write-restored-ok\n");
+
+    /* --- exec permission: copying an existing binary's bytes into a NEW
+       tmpfs file (no fork/exec, just plain read+write, like `cp` would)
+       never carries the exec bit over -- the copy starts at the same
+       fsModeDefaultFile every other fresh file gets, exactly like a real
+       shell script you just wrote needs `chmod +x` before `./it` works.
+       Reuses /bin/false (always exits 1) as the payload -- cheap, already
+       built, and its own fixed exit code doubles as proof the COPY, not
+       just some cached original, is what actually ran. --- */
+    if (copyFile("/bin/false", "/tmp/permd/prog") != 0) {
+        print("permtest: FAIL copy /bin/false to prog\n");
+        return 1;
+    }
+    if (userStat("/tmp/permd/prog", &st) != 0 || (st.mode & 0100) != 0) {
+        print("permtest: FAIL fresh copy already executable\n");
+        return 1;
+    }
+    print("permtest: copy-not-executable-ok\n");
+
+    if (userSpawn("/tmp/permd/prog", 0) >= 0) {
+        print("permtest: FAIL spawn succeeded without exec bit\n");
+        return 1;
+    }
+    print("permtest: exec-denied-ok\n");
+
+    if (userChmod("/tmp/permd/prog", 0755) != 0) {
+        print("permtest: FAIL chmod +x\n");
+        return 1;
+    }
+    long pid = userSpawn("/tmp/permd/prog", 0);
+    if (pid < 0) {
+        print("permtest: FAIL spawn after chmod +x\n");
+        return 1;
+    }
+    long status = userWait(pid);
+    if (status != 1) {
+        print("permtest: FAIL spawned copy did not exit 1\n");
+        return 1;
+    }
+    print("permtest: exec-after-chmod-ok\n");
+
+    print("permtest: PASS\n");
+    return 0;
+}