lxcsu userspace package

[lxc-userspace.git] / vsh.c

diff --git a/vsh.c b/vsh.c
new file mode 100644 (file)
index 0000000..76deb8b
--- /dev/null
+++ b/vsh.c
@@ -0,0 +1,83 @@
+/* Version 3 of vsh. Basically a wrapper around 'lxcsu -n -m <slicename>' - Sapan */
+
+#include <unistd.h>
+#include <pwd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#define VSH_PATH    "/usr/sbin/vsh"
+#ifndef PATH_MAX
+#define PATH_MAX    4096
+#endif
+
+#define LXCSU_PATH  "/usr/sbin/lxcsu"
+
+char* get_current_username (unsigned int uid)
+{
+    struct passwd *passwd_entry;
+    if ((passwd_entry = getpwuid(uid)) == NULL) {
+        fprintf(stderr, "Could not look up user record for %d\n", uid);
+        return NULL; 
+    }
+
+    return (strdup(passwd_entry->pw_name));
+}
+
+char **extend_argv(int argc, char **argv, int num_extra_args) {
+    int argc2, i;
+    char **argv2;
+
+    argc2 = argc + num_extra_args;
+    argv2 = (char **) malloc((argc2 + 1) * sizeof(char *));
+
+    if (!argv2)
+        return (char **) NULL;
+
+    for (i=0; i<argc; i++) {
+        argv2[i+num_extra_args]=strdup(argv[i]); 
+    }
+    argv2[argc2]=NULL;
+
+    return argv2;
+}
+
+#define NUM_LXCSU_EXEC_ARGS 3
+
+int main(int argc, char **argv, char **envp)
+{
+    char *slice_name;
+    char **argv2;
+    int argc2;
+    char slice_id_str[256];
+    unsigned int slice_xid;
+
+    slice_xid = getuid();
+    slice_name = get_current_username(slice_xid);
+    if (!slice_name) {
+        fprintf(stderr,"Could not look up slice name\n");
+        goto out_exception;
+    }
+    
+    argv2 = extend_argv(argc, argv, NUM_LXCSU_EXEC_ARGS);
+    if (!argv2) goto out_exception;
+        
+    
+    // Populate arguments
+    snprintf(slice_id_str, 255, "%u", slice_xid);
+    argv2[0] = strdup(LXCSU_PATH);
+    argv2[1] = strdup("-n");
+    argv2[2] = strdup("-m");
+    argv2[3] = strdup(slice_name);
+
+    if (setuid(geteuid())) goto out_exception;
+
+    execve(LXCSU_PATH, argv2, envp);
+
+out_exception:
+    printf("%s\n", strerror(errno));
+    return errno;
+}