glibc/glibc_post_upgrade.c

#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/time.h>
#include <dirent.h>
#include <stddef.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <elf.h>

#define verbose_exec(failcode, path...) \
  do							\
    {							\
      char *const arr[] = { path, NULL };		\
      vexec (failcode, arr);				\
    } while (0)

__attribute__((noinline)) void vexec (int failcode, char *const path[]);
__attribute__((noinline)) void says (const char *str);
__attribute__((noinline)) void sayn (long num);
__attribute__((noinline)) void message (char *const path[]);
__attribute__((noinline)) int check_elf (const char *name);

#ifdef __i386__
static int
is_ia64 (void)
{
  unsigned int fl1, fl2;

  /* See if we can use cpuid.  */
  __asm__ ("pushfl; pushfl; popl %0; movl %0,%1; xorl %2,%0;"
	   "pushl %0; popfl; pushfl; popl %0; popfl"
	   : "=&r" (fl1), "=&r" (fl2)
	   : "i" (0x00200000));
  if (((fl1 ^ fl2) & 0x00200000) == 0)
    return 0;

  /* Host supports cpuid.  See if cpuid gives capabilities, try
     CPUID(0).  Preserve %ebx and %ecx; cpuid insn clobbers these, we
     don't need their CPUID values here, and %ebx may be the PIC
     register.  */
  __asm__ ("pushl %%ecx; pushl %%ebx; cpuid; popl %%ebx; popl %%ecx"
	   : "=a" (fl1) : "0" (0) : "edx", "cc");
  if (fl1 == 0)
    return 0;

  /* Invoke CPUID(1), return %edx; caller can examine bits to
     determine what's supported.  */
  __asm__ ("pushl %%ecx; pushl %%ebx; cpuid; popl %%ebx; popl %%ecx"
	   : "=d" (fl2), "=a" (fl1) : "1" (1) : "cc");
  return (fl2 & (1 << 30)) != 0;
}
#else
#define is_ia64() 0
#endif

int
main (void)
{
  struct stat statbuf;
  char initpath[256];

  char buffer[4096];
  struct pref {
    char *p;
    int len;
  } prefix[] = { { "libc-", 5 }, { "libm-", 5 },
		 { "librt-", 6 }, { "libpthread-", 11 },
		 { "librtkaio-", 10 }, { "libthread_db-", 13 } };
  int i, j, fd;
  off_t base;
  ssize_t ret;
#ifdef __i386__
  const char *remove_dirs[] = { "/lib/tls", "/lib/i686", "/lib/tls/i486", "/lib/tls/i586", "/lib/tls/i686" };
#else
#ifndef LIBTLS
#define LIBTLS "/lib/tls"
#endif
  const char *remove_dirs[] = { LIBTLS };
#endif
  for (j = 0; j < sizeof (remove_dirs) / sizeof (remove_dirs[0]); ++j)
    {
      size_t rmlen = strlen (remove_dirs[j]);
      fd = open (remove_dirs[j], O_RDONLY);
      if (fd >= 0
	  && (ret = getdirentries (fd, buffer, sizeof (buffer), &base))
	     >= (ssize_t) offsetof (struct dirent, d_name))
	{
	  for (base = 0; base + offsetof (struct dirent, d_name) < ret; )
	    {
	      struct dirent *d = (struct dirent *) (buffer + base);

	      for (i = 0; i < sizeof (prefix) / sizeof (prefix[0]); i++)
		if (! strncmp (d->d_name, prefix[i].p, prefix[i].len))
		  {
		    char *p = d->d_name + prefix[i].len;

		    while (*p == '.' || (*p >= '0' && *p <= '9')) p++;
		    if (p[0] == 's' && p[1] == 'o' && p[2] == '\0'
			&& p + 3 - d->d_name
			   < sizeof (initpath) - rmlen - 1)
		      {
			memcpy (initpath, remove_dirs[j], rmlen);
			initpath[rmlen] = '/';
			strcpy (initpath + rmlen + 1, d->d_name);
			unlink (initpath);
			break;
		      }
		  }
	      base += d->d_reclen;
	    }
	  close (fd);
	}
    }

  int ldsocfd = open (LD_SO_CONF, O_RDONLY);
  struct stat ldsocst;
  if (ldsocfd >= 0 && fstat (ldsocfd, &ldsocst) >= 0)
    {
      char p[ldsocst.st_size + 1];
      if (read (ldsocfd, p, ldsocst.st_size) == ldsocst.st_size)
	{
	  p[ldsocst.st_size] = '\0';
	  if (strstr (p, "include ld.so.conf.d/*.conf") == NULL)
	    {
	      close (ldsocfd);
	      ldsocfd = open (LD_SO_CONF, O_WRONLY | O_TRUNC);
	      if (ldsocfd >= 0)
		{
		  size_t slen = strlen ("include ld.so.conf.d/*.conf\n");
		  if (write (ldsocfd, "include ld.so.conf.d/*.conf\n", slen)
		      != slen
		      || write (ldsocfd, p, ldsocst.st_size) != ldsocst.st_size)
		    _exit (109);
		}
	    }
	}
      if (ldsocfd >= 0)
	close (ldsocfd);
    }

  /* If installing bi-arch glibc, rpm sometimes doesn't unpack all files
     before running one of the lib's %post scriptlet.  /sbin/ldconfig will
     then be run by the other arch's %post.  */
  if (! access ("/sbin/ldconfig", X_OK))
    verbose_exec (110, "/sbin/ldconfig", "/sbin/ldconfig");

  if (! utimes (GCONV_MODULES_DIR "/gconv-modules.cache", NULL))
    {
#ifndef ICONVCONFIG
#define ICONVCONFIG "/usr/sbin/iconvconfig"
#endif
      const char *iconv_cache = GCONV_MODULES_DIR"/gconv-modules.cache";
      const char *iconv_dir = GCONV_MODULES_DIR;
      if (is_ia64 ())
	{
	  iconv_cache = "/emul/ia32-linux"GCONV_MODULES_DIR"/gconv-modules.cache";
	  iconv_dir = "/emul/ia32-linux"GCONV_MODULES_DIR;
	}
      verbose_exec (113, ICONVCONFIG, "/usr/sbin/iconvconfig",
		    "-o", iconv_cache,
		    "--nostdlib", iconv_dir);
    }

  /* Check if telinit is available and either SysVInit fifo,
     or upstart telinit.  */
  if (access ("/sbin/telinit", X_OK)
      || ((!!access ("/dev/initctl", F_OK))
	  ^ !access ("/sbin/initctl", X_OK)))
    _exit (0);

  /* Check if we are not inside of some chroot, because we'd just
     timeout and leave /etc/initrunlvl.

     On more modern systems this test is not sufficient to detect
     if we're in a chroot.  */
  if (readlink ("/proc/1/exe", initpath, 256) <= 0 ||
      readlink ("/proc/1/root", initpath, 256) <= 0)
    _exit (0);

  /* Here's another well known way to detect chroot, at least on an
     ext and xfs filesystems and assuming nothing mounted on the chroot's
     root. */
  if (stat ("/", &statbuf) != 0
      || (statbuf.st_ino != 2
	  && statbuf.st_ino != 128))
    _exit (0);

  if (check_elf ("/proc/1/exe"))
    verbose_exec (116, "/sbin/telinit", "/sbin/telinit", "u");

  /* Check if we can safely condrestart sshd.  */
  if (access ("/sbin/service", X_OK) == 0
      && access ("/usr/sbin/sshd", X_OK) == 0
      && access ("/etc/rc.d/init.d/sshd", X_OK) == 0
      && access ("/bin/bash", X_OK) == 0)
    {
      if (check_elf ("/usr/sbin/sshd"))
	verbose_exec (-121, "/sbin/service", "/sbin/service", "sshd", "condrestart");
    }

  _exit(0);
}

void
vexec (int failcode, char *const path[])
{
  pid_t pid;
  int status, save_errno;
  int devnull = 0;

  if (failcode < 0)
    {
      devnull = 1;
      failcode = -failcode;
    }
  pid = vfork ();
  if (pid == 0)
    {
      int fd;
      if (devnull && (fd = open ("/dev/null", O_WRONLY)) >= 0)
	{
	  dup2 (fd, 1);
	  dup2 (fd, 2);
	  close (fd);
	}
      execv (path[0], path + 1);
      save_errno = errno;
      message (path);
      says (" exec failed with errno ");
      sayn (save_errno);
      says ("\n");
      _exit (failcode);
    }
  else if (pid < 0)
    {
      save_errno = errno;
      message (path);
      says (" fork failed with errno ");
      sayn (save_errno);
      says ("\n");
      _exit (failcode + 1);
    }
  if (waitpid (0, &status, 0) != pid || !WIFEXITED (status))
    {
      message (path);
      says (" child terminated abnormally\n");
      _exit (failcode + 2);
    }
  if (WEXITSTATUS (status))
    {
      message (path);
      says (" child exited with exit code ");
      sayn (WEXITSTATUS (status));
      says ("\n");
      _exit (WEXITSTATUS (status));
    }
}

void
says (const char *str)
{
  write (1, str, strlen (str));
}

void
sayn (long num)
{
  char string[sizeof (long) * 3 + 1];
  char *p = string + sizeof (string) - 1;

  *p = '\0';
  if (num == 0)
    *--p = '0';
  else
    while (num)
      {
	*--p = '0' + num % 10;
	num = num / 10;
      }

  says (p);
}

void
message (char *const path[])
{
  says ("/usr/sbin/glibc_post_upgrade: While trying to execute ");
  says (path[0]);
}

int
check_elf (const char *name)
{
  /* Play safe, if we can't open or read, assume it might be
     ELF for the current arch.  */
  int ret = 1;
  int fd = open (name, O_RDONLY);
  if (fd >= 0)
    {
      Elf32_Ehdr ehdr;
      if (read (fd, &ehdr, offsetof (Elf32_Ehdr, e_version))
	  == offsetof (Elf32_Ehdr, e_version))
	{
	  ret = 0;
	  if (ehdr.e_ident[EI_CLASS]
	      == (sizeof (long) == 8 ? ELFCLASS64 : ELFCLASS32))
	    {
#if defined __i386__
	      ret = ehdr.e_machine == EM_386;
#elif defined __x86_64__
	      ret = ehdr.e_machine == EM_X86_64;
#elif defined __ia64__
	      ret = ehdr.e_machine == EM_IA_64;
#elif defined __powerpc64__
	      ret = ehdr.e_machine == EM_PPC64;
#elif defined __powerpc__
	      ret = ehdr.e_machine == EM_PPC;
#elif defined __s390__ || defined __s390x__
	      ret = ehdr.e_machine == EM_S390;
#elif defined __x86_64__
	      ret = ehdr.e_machine == EM_X86_64;
#elif defined __sparc__
	      if (sizeof (long) == 8)
		ret = ehdr.e_machine == EM_SPARCV9;
	      else
		ret = (ehdr.e_machine == EM_SPARC
		       || ehdr.e_machine == EM_SPARC32PLUS);
#else
	      ret = 1;
#endif
	    }
	}
      close (fd);
    }
  return ret;
}