fixed fstat/stat/readlink syscall.

components/lwp/lwp_syscall.c

@@ -612,7 +612,7 @@ int sys_fstat(int file, struct stat *buf)
 {
 #ifdef ARCH_MM_MMU
     int ret = -1;
-    struct stat statbuff;
+    struct stat statbuff = {0};
 
     if (!lwp_user_accessable((void *)buf, sizeof(struct stat)))
     {
@@ -2575,7 +2575,45 @@ int sys_log(const char* log, int size)
 int sys_stat(const char *file, struct stat *buf)
 {
     int ret = 0;
-    ret = stat(file, buf);
+    int err;
+    size_t len;
+    size_t copy_len;
+    char *copy_path;
+    struct stat statbuff = {0};
+
+    if (!lwp_user_accessable((void *)buf, sizeof(struct stat)))
+    {
+        return -EFAULT;
+    }
+
+    len = lwp_user_strlen(file, &err);
+    if (err)
+    {
+        return -EFAULT;
+    }
+
+    copy_path = (char*)rt_malloc(len + 1);
+    if (!copy_path)
+    {
+        return -ENOMEM;
+    }
+
+    copy_len = lwp_get_from_user(copy_path, (void*)file, len);
+    if (copy_len == 0)
+    {
+        rt_free(copy_path);
+        return -EFAULT;
+    }
+    copy_path[copy_len] = '\0';
+
+    ret = stat(copy_path, &statbuff);
+    rt_free(copy_path);
+
+    if (ret == 0)
+    {
+        lwp_put_to_user(buf, &statbuff, sizeof statbuff);
+    }
+
     return (ret < 0 ? GET_ERRNO() : ret);
 }
 
@@ -4157,6 +4195,67 @@ int sys_getrandom(void *buf, size_t buflen, unsigned int flags)
 #endif
     return ret;
 }
+
+ssize_t sys_readlink(char* path, char *buf, size_t bufsz)
+{
+    size_t len, copy_len;
+    int err;
+    int fd = -1;
+    struct dfs_fd *d;
+    char *copy_path;
+
+    len = lwp_user_strlen(path, &err);
+    if (err)
+    {
+        return -EFAULT;
+    }
+
+    if (!lwp_user_accessable(buf, bufsz))
+    {
+        return -EINVAL;
+    }
+
+    copy_path = (char*)rt_malloc(len + 1);
+    if (!copy_path)
+    {
+        return -ENOMEM;
+    }
+
+    copy_len = lwp_get_from_user(copy_path, path, len);
+    copy_path[copy_len] = '\0';
+
+    /* musl __procfdname */
+    err = sscanf(copy_path, "/proc/self/fd/%d", &fd);
+    rt_free(copy_path);
+
+    if (err != 1)
+    {
+        LOG_E("readlink: path not is /proc/self/fd/* , call by musl __procfdname()?");
+        return -EINVAL;
+    }
+
+    d = fd_get(fd);
+    if (!d)
+    {
+        return -EBADF;
+    }
+
+    if (!d->vnode)
+    {
+        return -EBADF;
+    }
+
+    copy_len = strlen(d->vnode->fullpath);
+    if (copy_len > bufsz)
+    {
+        copy_len = bufsz;
+    }
+
+    bufsz = lwp_put_to_user(buf, d->vnode->fullpath, copy_len);
+
+    return bufsz;
+}
+
 int sys_setaffinity(pid_t pid, size_t size, void *set)
 {
     if (!lwp_user_accessable(set, sizeof(cpu_set_t)))
@@ -4672,7 +4771,7 @@ const static void* func_table[] =
     SYSCALL_SIGN(sys_setrlimit),
     SYSCALL_SIGN(sys_setsid),
     SYSCALL_SIGN(sys_getrandom),
-    SYSCALL_SIGN(sys_notimpl),    // SYSCALL_SIGN(sys_readlink)     /* 145 */
+    SYSCALL_SIGN(sys_readlink),    // SYSCALL_SIGN(sys_readlink)     /* 145 */
     SYSCALL_USPACE(SYSCALL_SIGN(sys_mremap)),
     SYSCALL_USPACE(SYSCALL_SIGN(sys_madvise)),
     SYSCALL_SIGN(sys_sched_setparam),