Userland: Use CFile in ps

Author: https://github.com/rburchell
Commit: https://github.com/SerenityOS/serenity/commit/9a4ec2e92a9
Pull-request: https://github.com/SerenityOS/serenity/pull/167

Userland/ps.cpp

@@ -1,28 +1,20 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <LibCore/CFile.h>
 
 int main(int argc, char** argv)
 {
     (void) argc;
     (void) argv;
-    int fd = open("/proc/summary", O_RDONLY);
-    if (fd == -1) {
-        perror("failed to open /proc/summary");
+
+    CFile f("/proc/summary");
+    if (!f.open(CIODevice::ReadOnly)) {
+        fprintf(stderr, "open: failed to open /proc/summary: %s", f.error_string());
         return 1;
     }
-    for (;;) {
-        char buf[128];
-        ssize_t nread = read(fd, buf, sizeof(buf));
-        if (nread == 0)
-            break;
-        if (nread < 0) {
-            perror("failed to read");
-            return 2;
-        }
-        for (ssize_t i = 0; i < nread; ++i) {
-            putchar(buf[i]);
-        }
-    }
+    const auto& b = f.read_all();
+    for (auto i = 0; i < b.size(); ++i)
+        putchar(b[i]);
     return 0;
 }