inspect: Refuse to parse /etc/fstab if it is huge.

[libguestfs.git] / fish / alloc.c

diff --git a/fish/alloc.c b/fish/alloc.c
index a7d115a..7799e4e 100644 (file)
--- a/fish/alloc.c
+++ b/fish/alloc.c
@@ -24,23 +24,51 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <inttypes.h>
+#include <errno.h>
 
-#include "fish.h"
+#include "xstrtol.h"
 
-static int parse_size (const char *str, off_t *size_rtn);
+#include "fish.h"
 
 int
-do_alloc (const char *cmd, int argc, char *argv[])
+run_alloc (const char *cmd, size_t argc, char *argv[])
 {
-  off_t size;
-  int fd;
-
   if (argc != 2) {
     fprintf (stderr, _("use 'alloc file size' to create an image\n"));
     return -1;
   }
 
-  if (parse_size (argv[1], &size) == -1)
+  if (alloc_disk (argv[0], argv[1], 1, 0) == -1)
+    return -1;
+
+  return 0;
+}
+
+int
+run_sparse (const char *cmd, size_t argc, char *argv[])
+{
+  if (argc != 2) {
+    fprintf (stderr, _("use 'sparse file size' to create a sparse image\n"));
+    return -1;
+  }
+
+  if (alloc_disk (argv[0], argv[1], 1, 1) == -1)
+    return -1;
+
+  return 0;
+}
+
+/* This is the underlying allocation function.  It's called from
+ * a few other places in guestfish.
+ */
+int
+alloc_disk (const char *filename, const char *size_str, int add, int sparse)
+{
+  off_t size;
+  int fd;
+  char c = 0;
+
+  if (parse_size (size_str, &size) == -1)
     return -1;
 
   if (!guestfs_is_config (g)) {
@@ -48,57 +76,85 @@ do_alloc (const char *cmd, int argc, char *argv[])
     return -1;
   }
 
-  fd = open (argv[0], O_WRONLY|O_CREAT|O_NOCTTY|O_TRUNC, 0666);
+  fd = open (filename, O_WRONLY|O_CREAT|O_NOCTTY|O_TRUNC, 0666);
   if (fd == -1) {
-    perror (argv[0]);
+    perror (filename);
     return -1;
   }
 
-  if (posix_fallocate (fd, 0, size) == -1) {
-    perror ("fallocate");
-    close (fd);
-    unlink (argv[0]);
-    return -1;
+  if (!sparse) {                /* Not sparse */
+#ifdef HAVE_POSIX_FALLOCATE
+    int err = posix_fallocate (fd, 0, size);
+    if (err != 0) {
+      errno = err;
+      perror ("fallocate");
+      close (fd);
+      unlink (filename);
+      return -1;
+    }
+#else
+    /* Slow emulation of posix_fallocate on platforms which don't have it. */
+    char buffer[BUFSIZ];
+    memset (buffer, 0, sizeof buffer);
+
+    size_t remaining = size;
+    while (remaining > 0) {
+      size_t n = remaining > sizeof buffer ? sizeof buffer : remaining;
+      ssize_t r = write (fd, buffer, n);
+      if (r == -1) {
+        perror ("write");
+        close (fd);
+        unlink (filename);
+        return -1;
+      }
+      remaining -= r;
+    }
+#endif
+  } else {                      /* Sparse */
+    if (lseek (fd, size-1, SEEK_SET) == (off_t) -1) {
+      perror ("lseek");
+      close (fd);
+      unlink (filename);
+      return -1;
+    }
+
+    if (write (fd, &c, 1) != 1) {
+      perror ("write");
+      close (fd);
+      unlink (filename);
+      return -1;
+    }
   }
 
   if (close (fd) == -1) {
-    perror (argv[0]);
-    unlink (argv[0]);
+    perror (filename);
+    unlink (filename);
     return -1;
   }
 
-  if (guestfs_add_drive (g, argv[0]) == -1) {
-    unlink (argv[0]);
-    return -1;
+  if (add) {
+    if (guestfs_add_drive_opts (g, filename,
+                                GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
+                                -1) == -1) {
+      unlink (filename);
+      return -1;
+    }
   }
 
   return 0;
 }
 
-static int
+int
 parse_size (const char *str, off_t *size_rtn)
 {
-  uint64_t size;
-  char type;
-
-  /* Note that the parsing here is looser than what is specified in the
-   * help, but we may tighten it up in future so beware.
-   */
-  if (sscanf (str, "%"SCNu64"%c", &size, &type) == 2) {
-    switch (type) {
-    case 'k': case 'K': size *= 1024; break;
-    case 'm': case 'M': size *= 1024 * 1024; break;
-    case 'g': case 'G': size *= 1024 * 1024 * 1024; break;
-    case 's': size *= 512; break;
-    default:
-      fprintf (stderr, _("could not parse size specification '%s'\n"), str);
-      return -1;
-    }
-  }
-  else if (sscanf (str, "%"SCNu64, &size) == 1)
-    size *= 1024;
-  else {
-    fprintf (stderr, _("could not parse size specification '%s'\n"), str);
+  unsigned long long size;
+  strtol_error xerr;
+
+  xerr = xstrtoull (str, NULL, 0, &size, "0kKMGTPEZY");
+  if (xerr != LONGINT_OK) {
+    fprintf (stderr,
+             _("%s: invalid integer parameter (%s returned %d)\n"),
+             "parse_size", "xstrtoull", xerr);
     return -1;
   }