X-Git-Url: http://git.annexia.org/?p=libguestfs.git;a=blobdiff_plain;f=src%2Fappliance.c;h=7dc42c1f7a4abc6d19e78fed15786251d4cd6313;hp=28f1595f07c9267cec5230ff60652f8711e6d994;hb=7fc338690f385c2495b7ba5f98346a5c057991ea;hpb=ec736e20d32febefa2fe35d503886e0999146f0e

diff --git a/src/appliance.c b/src/appliance.c
index 28f1595..7dc42c1 100644
--- a/src/appliance.c
+++ b/src/appliance.c
@@ -18,6 +18,8 @@
 
 #include <config.h>
 
+#include <errno.h>
+#include <dirent.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
@@ -39,8 +41,8 @@
 #include "guestfs-internal-actions.h"
 #include "guestfs_protocol.h"
 
-static const char *kernel_name = "vmlinuz." REPO "." host_cpu;
-static const char *initrd_name = "initramfs." REPO "." host_cpu ".img";
+static const char *kernel_name = "vmlinuz." host_cpu;
+static const char *initrd_name = "initramfs." host_cpu ".img";
 
 static int find_path (guestfs_h *g, int (*pred) (guestfs_h *g, const char *pelem, void *data), void *data, char **pelem);
 static int dir_contains_file (const char *dir, const char *file);
@@ -159,13 +161,27 @@ calculate_supermin_checksum (guestfs_h *g, const char *supermin_path)
 {
   size_t len = 2 * strlen (supermin_path) + 256;
   char cmd[len];
-  snprintf (cmd, len,
-            "febootstrap-supermin-helper%s "
-            "-f checksum "
-            "'%s/supermin.d' "
-            host_cpu,
-            g->verbose ? " --verbose" : "",
-            supermin_path);
+  int pass_u_g_args = getuid () != geteuid () || getgid () != getegid ();
+
+  if (!pass_u_g_args)
+    snprintf (cmd, len,
+              "febootstrap-supermin-helper%s "
+              "-f checksum "
+              "'%s/supermin.d' "
+              host_cpu,
+              g->verbose ? " --verbose" : "",
+              supermin_path);
+  else
+    snprintf (cmd, len,
+              "febootstrap-supermin-helper%s "
+              "-u %i "
+              "-g %i "
+              "-f checksum "
+              "'%s/supermin.d' "
+              host_cpu,
+              g->verbose ? " --verbose" : "",
+              geteuid (), getegid (),
+              supermin_path);
 
   if (g->verbose)
     guestfs___print_timestamped_message (g, "%s", cmd);
@@ -235,9 +251,9 @@ check_for_cached_appliance (guestfs_h *g,
 {
   const char *tmpdir = guestfs_tmpdir ();
 
-  size_t len = strlen (tmpdir) + strlen (checksum) + 2;
+  size_t len = strlen (tmpdir) + strlen (checksum) + 10;
   char cachedir[len];
-  snprintf (cachedir, len, "%s/%s", tmpdir, checksum);
+  snprintf (cachedir, len, "%s/guestfs.%s", tmpdir, checksum);
 
   /* Touch the directory to prevent it being deleting in a rare race
    * between us doing the checks and a tmp cleaner running.  Note this
@@ -328,28 +344,105 @@ build_supermin_appliance (guestfs_h *g,
     guestfs___print_timestamped_message (g, "begin building supermin appliance");
 
   const char *tmpdir = guestfs_tmpdir ();
-  size_t cdlen = strlen (tmpdir) + strlen (checksum) + 2;
-  char cachedir[cdlen];
-  snprintf (cachedir, cdlen, "%s/%s", tmpdir, checksum);
 
-  /* Don't worry about this failing, because the
-   * febootstrap-supermin-helper command will fail if the directory
-   * doesn't exist.  Note the directory might already exist, eg. if a
-   * tmp cleaner has removed the existing appliance but not the
-   * directory itself.
-   */
-  (void) mkdir (cachedir, 0755);
+  size_t tmpcdlen = strlen (tmpdir) + 16;
+  char tmpcd[tmpcdlen];
+  snprintf (tmpcd, tmpcdlen, "%s/guestfs.XXXXXX", tmpdir);
+
+  if (NULL == mkdtemp (tmpcd)) {
+    error (g, _("failed to create temporary cache directory: %m"));
+    return -1;
+  }
 
   if (g->verbose)
     guestfs___print_timestamped_message (g, "run febootstrap-supermin-helper");
 
-  int r = run_supermin_helper (g, supermin_path, cachedir, cdlen);
+  int r = run_supermin_helper (g, supermin_path, tmpcd, tmpcdlen);
   if (r == -1)
     return -1;
 
   if (g->verbose)
     guestfs___print_timestamped_message (g, "finished building supermin appliance");
 
+  size_t cdlen = strlen (tmpdir) + strlen (checksum) + 10;
+  char cachedir[cdlen];
+  snprintf (cachedir, cdlen, "%s/guestfs.%s", tmpdir, checksum);
+
+  /* Make the temporary directory world readable */
+  if (chmod (tmpcd, 0755) == -1) {
+    error (g, "chmod %s: %m", tmpcd);
+  }
+
+  /* Try to rename the temporary directory to its non-temporary name */
+  if (rename (tmpcd, cachedir) == -1) {
+    /* If the cache directory now exists, we may have been racing with another
+     * libguestfs process. Check the new directory and use it if it's valid. */
+    if (errno == ENOTEMPTY || errno == EEXIST) {
+      /* Appliance cache consists of 2 files and a symlink in the cache
+       * directory. Delete them first. */
+      DIR *dir = opendir (tmpcd);
+      if (dir == NULL) {
+        error (g, "opendir %s: %m", tmpcd);
+        return -1;
+      }
+
+      int fd = dirfd (dir);
+      if (fd == -1) {
+        error (g, "dirfd: %m");
+        closedir (dir);
+        return -1;
+      }
+
+      struct dirent *dirent;
+      for (;;) {
+        errno = 0;
+        dirent = readdir (dir);
+
+        if (dirent == NULL) {
+          break;
+        }
+
+        /* Check that dirent is a file so we don't try to delete . and .. */
+        struct stat st;
+        if (fstatat (fd, dirent->d_name, &st, AT_SYMLINK_NOFOLLOW) == -1) {
+          error (g, "fstatat %s: %m", dirent->d_name);
+          return -1;
+        }
+
+        if (!S_ISDIR(st.st_mode)) {
+          if (unlinkat (fd, dirent->d_name, 0) == -1) {
+            error (g, "unlinkat %s: %m", dirent->d_name);
+            closedir (dir);
+            return -1;
+          }
+        }
+      }
+
+      if (errno != 0) {
+        error (g, "readdir %s: %m", tmpcd);
+        closedir (dir);
+        return -1;
+      }
+
+      closedir (dir);
+
+      /* Delete the temporary cache directory itself. */
+      if (rmdir (tmpcd) == -1) {
+        error (g, "rmdir %s: %m", tmpcd);
+        return -1;
+      }
+
+      /* Check the new cache directory, and return it if valid */
+      return check_for_cached_appliance (g, supermin_path, checksum,
+                                         kernel, initrd, appliance);
+    }
+
+    else {
+      error (g, _("error renaming temporary cache directory: %m"));
+      return -1;
+    }
+  }
+
   *kernel = safe_malloc (g, cdlen + 8 /* / + "kernel" + \0 */);
   *initrd = safe_malloc (g, cdlen + 8 /* / + "initrd" + \0 */);
   *appliance = safe_malloc (g, cdlen + 6 /* / + "root" + \0 */);
@@ -361,16 +454,50 @@ build_supermin_appliance (guestfs_h *g,
 }
 
 /* Run febootstrap-supermin-helper and tell it to generate the
- * appliance.  Note that we have to do an explicit fork/exec here.
- * 'system' goes via the shell, and on systems that have bash, bash
- * has a misfeature where it resets the euid to uid which breaks
- * virt-v2v.  'posix_spawn' was also considered but that doesn't allow
- * us to reset the umask.
+ * appliance.
  */
 static int
 run_supermin_helper (guestfs_h *g, const char *supermin_path,
                      const char *cachedir, size_t cdlen)
 {
+  size_t pathlen = strlen (supermin_path);
+
+  const char *argv[30];
+  size_t i = 0;
+
+  char uid[32];
+  snprintf (uid, sizeof uid, "%i", geteuid ());
+  char gid[32];
+  snprintf (gid, sizeof gid, "%i", getegid ());
+  char supermin_d[pathlen + 32];
+  snprintf (supermin_d, pathlen + 32, "%s/supermin.d", supermin_path);
+  char kernel[cdlen + 32];
+  snprintf (kernel, cdlen + 32, "%s/kernel", cachedir);
+  char initrd[cdlen + 32];
+  snprintf (initrd, cdlen + 32, "%s/initrd", cachedir);
+  char root[cdlen + 32];
+  snprintf (root, cdlen + 32, "%s/root", cachedir);
+
+  int pass_u_g_args = getuid () != geteuid () || getgid () != getegid ();
+
+  argv[i++] = "febootstrap-supermin-helper";
+  if (g->verbose)
+    argv[i++] = "--verbose";
+  if (pass_u_g_args) {
+    argv[i++] = "-u";
+    argv[i++] = uid;
+    argv[i++] = "-g";
+    argv[i++] = gid;
+  }
+  argv[i++] = "-f";
+  argv[i++] = "ext2";
+  argv[i++] = supermin_d;
+  argv[i++] = host_cpu;
+  argv[i++] = kernel;
+  argv[i++] = initrd;
+  argv[i++] = root;
+  argv[i++] = NULL;
+
   pid_t pid = fork ();
   if (pid == -1) {
     perrorf (g, "fork");
@@ -378,6 +505,9 @@ run_supermin_helper (guestfs_h *g, const char *supermin_path,
   }
 
   if (pid > 0) {                /* Parent. */
+    if (g->verbose)
+      guestfs___print_timestamped_argv (g, argv);
+
     int status;
     if (waitpid (pid, &status, 0) == -1) {
       perrorf (g, "waitpid");
@@ -397,57 +527,6 @@ run_supermin_helper (guestfs_h *g, const char *supermin_path,
    */
   umask (0022);
 
-  /* Set uid/gid in the child.  This is a workaround for a misfeature
-   * in bash which breaks virt-v2v - see the comment at the top of
-   * this function.
-   */
-  if (getuid () == 0) {
-    int egid = getegid ();
-    int euid = geteuid ();
-
-    if (egid != 0 || euid != 0) {
-      if (seteuid (0) == -1) {
-        perror ("seteuid");
-        _exit (EXIT_FAILURE);
-      }
-
-      if (setgid (egid) == -1) {
-        perror ("setgid");
-        _exit (EXIT_FAILURE);
-      }
-
-      if (setuid (euid) == -1) {
-        perror ("setuid");
-        _exit (EXIT_FAILURE);
-      }
-    }
-  }
-
-  size_t pathlen = strlen (supermin_path);
-
-  const char *argv[30];
-  size_t i = 0;
-
-  argv[i++] = "febootstrap-supermin-helper";
-  if (g->verbose)
-    argv[i++] = "--verbose";
-  argv[i++] = "-f";
-  argv[i++] = "ext2";
-  char supermin_d[pathlen + 32];
-  snprintf (supermin_d, pathlen + 32, "%s/supermin.d", supermin_path);
-  argv[i++] = supermin_d;
-  argv[i++] = host_cpu;
-  char kernel[cdlen + 32];
-  snprintf (kernel, cdlen + 32, "%s/kernel", cachedir);
-  argv[i++] = kernel;
-  char initrd[cdlen + 32];
-  snprintf (initrd, cdlen + 32, "%s/initrd", cachedir);
-  argv[i++] = initrd;
-  char root[cdlen + 32];
-  snprintf (root, cdlen + 32, "%s/root", cachedir);
-  argv[i++] = root;
-  argv[i++] = NULL;
-
   execvp ("febootstrap-supermin-helper", (char * const *) argv);
   perror ("execvp");
   _exit (EXIT_FAILURE);