isemacsvalid.c

/* isemacsvalid.c -*- C -*- */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>

#include "dumpemacs.h"

int is_emacs_valid(int debugflag)
{
  struct stat sb;
  int ret;
  time_t lastMod;

  ret = lstat(kEmacsArchPath, &sb);
  if (ret == -1) {
    if (errno == ENOENT) {
      return 0; /* regenerate it */
    } else {
      return -1; /* error */
    }
  }

  if (S_ISDIR(sb.st_mode)) {
    errno = EISDIR;
    return -1;
  } else if (!S_ISREG(sb.st_mode)) {
    /* if it is not a file, then nuke it: */
    return 0;
  }

  /* It is a file. Check the times: */
  lastMod = sb.st_mtime;

  /* validate that the per-arch executable is
   * newer than the wrapper or dumpemacs: */
  ret = lstat(kEmacsWrapperPath, &sb);
  if (ret == -1) {
    return -1; /* error */
  }

  if (sb.st_mtime > lastMod) {
    /* if the wrapper is more recent than the per-arch, then: */
    return 0; /* (i.e. regenerate it) */
  }

  ret = lstat(kDumpEmacsPath, &sb);
  if (ret == -1) {
    return -1; /* error */
  }

  if (sb.st_mtime > lastMod) {
    /* if the dumpemacs is more recent than the per-arch, then: */
    return 0; /* (i.e. regenerate it) */
  }

  if (debugflag > 0) {
    printf("debugflag is %d.\n", debugflag);
  }

  /* per-arch emacs is present and newer than the
   * infrastructure tools, so let it be: */
  return 1;
}

/* The Makefile will define this for us when building the executable: */
#ifdef STANDALONE_ISEMACSVALID
/* a header providing a library interface to the machochecker program,
 * whose sources we stole from ld64: */
# include "machochecker.h"
int main(int argc, const char* argv[])
{
  int ret = is_emacs_valid(0);
  int printed = printf("Is emacs valid?\n");
  switch (ret) {
    case -1:
      printed += fprintf(stderr, "Error");
      if (errno != 0) {
        printed += fprintf(stderr, ": %d (i.e. \"%s\")\n", errno,
        		   strerror(errno));
      } else {
        printed += fprintf(stderr, ".\n");
      }
      break;
    case 0:
      printed += printf("Per-arch emacs is outdated; need to regenerate it.\n");
      break;
    case 1:
      printed += printf("Per-arch emacs is present and new enough, so let it be.\n");
      break;
    default:
      printed += fprintf(stderr, "Unhandled return value for is_emacs_valid()!\n");
      break;
  }

  /* FIXME: munge argv to insert proper path to built emacs, if needed: */
  ret = machocheck_main(argc, argv);

  printed += printf("machocheck_main() returned %d: %s.\n", ret,
                    ((ret == 0) ? "success, should be valid" : "failure, invalid"));
  if (printed)
    return ret;
  else
    exit(EXIT_FAILURE);
}
#endif /* STANDALONE_ISEMACSVALID */

/* EOF */