1 files changed, 66 insertions, 0 deletions
diff --git a/exec.mm b/exec.mm
new file mode 100644
index 0000000..751a84a
--- /dev/null
+++ b/exec.mm
@@ -0,0 +1,66 @@
+#include <Foundation/Foundation.h>
+#include <CoreFoundation/CoreFoundation.h>
+
+#include <sys/types.h>
+#include <pwd.h>
+#include <unistd.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+const char *Firmware_ = NULL;
+
+unsigned Major_;
+unsigned Minor_;
+unsigned BugFix_;
+
+#define FW_LEAST(major, minor, bugfix) \
+    (major < Major_ || major == Major_ && \
+        (minor < Minor_ || minor == Minor_ && \
+            bugfix <= BugFix_))
+
+int main(int argc, char *argv[]) {
+    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+
+    if (NSDictionary *sysver = [NSDictionary dictionaryWithContentsOfFile:@"/System/Library/CoreServices/SystemVersion.plist"]) {
+        if (NSString *prover = [sysver valueForKey:@"ProductVersion"]) {
+            Firmware_ = strdup([prover cString]);
+            NSArray *versions = [prover componentsSeparatedByString:@"."];
+            int count = [versions count];
+            Major_ = count > 0 ? [[versions objectAtIndex:0] intValue] : 0;
+            Minor_ = count > 1 ? [[versions objectAtIndex:1] intValue] : 0;
+            BugFix_ = count > 2 ? [[versions objectAtIndex:2] intValue] : 0;
+        }
+    }
+
+    [pool release];
+
+    const char *user;
+    if (FW_LEAST(1,1,3))
+        user = "mobile";
+    else
+        user = "root";
+
+    if (argc == 1)
+        printf("%s\n", user);
+    else {
+        struct passwd *passwd = getpwnam(user);
+
+        if (setreuid(passwd->pw_uid, 0) == -1) {
+            perror("setreuid");
+            exit(1);
+        }
+
+        if (setregid(passwd->pw_gid, 0) == -1) {
+            perror("setregid");
+            exit(1);
+        }
+
+        if (execvp(argv[1], argv + 1) == -1) {
+            perror("execvp");
+            exit(1);
+        }
+    }
+
+    return 0;
+}