athena/src/gekko_support.c

#if defined(GEKKO)
#include "gekko_support.h"
#define SYMLOOP_MAX 8
#include <sys/stat.h>
#include <sys/param.h>
#include <stddef.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>

/* A slightly modified copy of this file exists in libexec/ld.so */

/*
 * char *realpath(const char *path, char resolved[PATH_MAX]);
 *
 * Find the real name of path, by removing all ".", ".." and symlink
 * components.  Returns (resolved) on success, or (NULL) on failure,
 * in which case the path which caused trouble is left in (resolved).
 */
char *
realpath(const char *path, char *resolved)
{
	struct stat sb;
	char *p, *q, *s;
	size_t left_len, resolved_len;
	unsigned symlinks;
	int serrno, slen, mem_allocated;
	char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];

	if (path[0] == '\0') {
		errno = ENOENT;
		return (NULL);
	}

	serrno = errno;

	if (resolved == NULL) {
		resolved = malloc(PATH_MAX);
		if (resolved == NULL)
			return (NULL);
		mem_allocated = 1;
	} else
		mem_allocated = 0;

	symlinks = 0;
	if (path[0] == '/') {
		resolved[0] = '/';
		resolved[1] = '\0';
		if (path[1] == '\0')
			return (resolved);
		resolved_len = 1;
		left_len = strlcpy(left, path + 1, sizeof(left));
	} else {
		if (getcwd(resolved, PATH_MAX) == NULL) {
			if (mem_allocated)
				free(resolved);
			else
				strlcpy(resolved, ".", PATH_MAX);
			return (NULL);
		}
		resolved_len = strlen(resolved);
		left_len = strlcpy(left, path, sizeof(left));
	}
	if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
		errno = ENAMETOOLONG;
		goto err;
	}

	/*
	 * Iterate over path components in `left'.
	 */
	while (left_len != 0) {
		/*
		 * Extract the next path component and adjust `left'
		 * and its length.
		 */
		p = strchr(left, '/');
		s = p ? p : left + left_len;
		if (s - left >= sizeof(next_token)) {
			errno = ENAMETOOLONG;
			goto err;
		}
		memcpy(next_token, left, s - left);
		next_token[s - left] = '\0';
		left_len -= s - left;
		if (p != NULL)
			memmove(left, s + 1, left_len + 1);
		if (resolved[resolved_len - 1] != '/') {
			if (resolved_len + 1 >= PATH_MAX) {
				errno = ENAMETOOLONG;
				goto err;
			}
			resolved[resolved_len++] = '/';
			resolved[resolved_len] = '\0';
		}
		if (next_token[0] == '\0')
			continue;
		else if (strcmp(next_token, ".") == 0)
			continue;
		else if (strcmp(next_token, "..") == 0) {
			/*
			 * Strip the last path component except when we have
			 * single "/"
			 */
			if (resolved_len > 1) {
				resolved[resolved_len - 1] = '\0';
				q = strrchr(resolved, '/') + 1;
				*q = '\0';
				resolved_len = q - resolved;
			}
			continue;
		}

		/*
		 * Append the next path component and lstat() it. If
		 * lstat() fails we still can return successfully if
		 * there are no more path components left.
		 */
		resolved_len = strlcat(resolved, next_token, PATH_MAX);
		if (resolved_len >= PATH_MAX) {
			errno = ENAMETOOLONG;
			goto err;
		}
		if (lstat(resolved, &sb) != 0) {
			if (errno == ENOENT && p == NULL) {
				errno = serrno;
				return (resolved);
			}
			goto err;
		}
		if (S_ISLNK(sb.st_mode)) {
			if (symlinks++ > SYMLOOP_MAX) {
				errno = ELOOP;
				goto err;
			}
			slen = readlink(resolved, symlink, sizeof(symlink) - 1);
			if (slen < 0)
				goto err;
			symlink[slen] = '\0';
			if (symlink[0] == '/') {
				resolved[1] = 0;
				resolved_len = 1;
			} else if (resolved_len > 1) {
				/* Strip the last path component. */
				resolved[resolved_len - 1] = '\0';
				q = strrchr(resolved, '/') + 1;
				*q = '\0';
				resolved_len = q - resolved;
			}

			/*
			 * If there are any path components left, then
			 * append them to symlink. The result is placed
			 * in `left'.
			 */
			if (p != NULL) {
				if (symlink[slen - 1] != '/') {
					if (slen + 1 >= sizeof(symlink)) {
						errno = ENAMETOOLONG;
						goto err;
					}
					symlink[slen] = '/';
					symlink[slen + 1] = 0;
				}
				left_len = strlcat(symlink, left, sizeof(symlink));
				if (left_len >= sizeof(left)) {
					errno = ENAMETOOLONG;
					goto err;
				}
			}
			left_len = strlcpy(left, symlink, sizeof(left));
		}
	}

	/*
	 * Remove trailing slash except when the resolved pathname
	 * is a single "/".
	 */
	if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
		resolved[resolved_len - 1] = '\0';
	return (resolved);

err:
	if (mem_allocated)
		free(resolved);
	return (NULL);
}

static int
int_vasprintf (result, format, args)
     char **result;
     const char *format;
     va_list *args;
{
  const char *p = format;
  /* Add one to make sure that it is never zero, which might cause malloc
     to return NULL.  */
  int total_width = strlen (format) + 1;
  va_list ap;

  memcpy ((void*) &ap, (void*) args, sizeof (va_list));

  while (*p != '\0')
    {
      if (*p++ == '%')
        {
          while (strchr ("-+ #0", *p))
            ++p;
          if (*p == '*')
            {
              ++p;
              total_width += abs (va_arg (ap, int));
            }
          else
            total_width += strtoul (p, (char**)&p, 10);
          if (*p == '.')
            {
              ++p;
              if (*p == '*')
                {
                  ++p;
                  total_width += abs (va_arg (ap, int));
                }
              else
              total_width += strtoul (p, (char**)&p, 10);
            }
          while (strchr ("hlL", *p))
            ++p;
          /* Should be big enough for any format specifier except %s and floats.  */
          total_width += 30;
          switch (*p)
            {
            case 'd':
            case 'i':
            case 'o':
            case 'u':
            case 'x':
            case 'X':
            case 'c':
              (void) va_arg (ap, int);
              break;
            case 'f':
            case 'e':
            case 'E':
            case 'g':
            case 'G':
              (void) va_arg (ap, double);
              /* Since an ieee double can have an exponent of 307, we'll
                 make the buffer wide enough to cover the gross case. */
              total_width += 307;
              break;
            case 's':
              total_width += strlen (va_arg (ap, char *));
              break;
            case 'p':
            case 'n':
              (void) va_arg (ap, char *);
              break;
            }
        }
    }
#ifdef TEST
  global_total_width = total_width;
#endif
  *result = malloc (total_width);
  if (*result != NULL)
    return vsprintf (*result, format, *args);
  else
    return 0;
}

int
vasprintf (result, format, args)
     char **result;
     const char *format;
#if defined (_BSD_VA_LIST_) && defined (__FreeBSD__)
     _BSD_VA_LIST_ args;
#else
     va_list args;
#endif
{
  return int_vasprintf (result, format, &args);
}

int
vsnprintf (char *s, size_t n, const char *format, va_list ap)
{
  char *buf = 0;
  int result = vasprintf (&buf, format, ap);

  if (!buf)
    return -1;
  if (result < 0)
    {
      free (buf);
      return -1;
    }

  result = strlen (buf);
  if (n > 0)
    {
      if ((long) n > result)
        memcpy (s, buf, result+1);
      else
        {
          memcpy (s, buf, n-1);
          s[n - 1] = 0;
        }
    }
  free (buf);
  return result;
}
#endif