WebSVN – HelenOS – Diff – /trunk/uspace/app/bdsh/util.c

 /* Copyright (c) 2008, Tim Post <tinkertim@gmail.com>
  * Copyright (C) 1998 by Wes Peters <wes@softweyr.com>
  * Copyright (c) 1988, 1993 The Regents of the University of California.
  * All rights reserved by all copyright holders.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
+ *
  * Redistributions of source code must retain the above copyright notice, this
  * list of conditions and the following disclaimer.
+ *
  * Redistributions in binary form must reproduce the above copyright notice,
  * this list of conditions and the following disclaimer in the documentation
  * and/or other materials provided with the distribution.
+ *
  * Neither the name of the original program's authors nor the names of its
  * contributors may be used to endorse or promote products derived from this
  * software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 /* NOTES:
  * 1 - Various functions were adapted from FreeBSD (copyright holders noted above)
  *     these functions are identified with comments.
+ *
  * 2 - Some of these have since appeared in libc. They remain here for various
  *     reasons, such as the eventual integration of garbage collection for things
  *     that allocate memory and don't automatically free it.
+ *
  * 3 - Things that expect a pointer to an allocated string do _no_ sanity checking
  *     if developing on a simulator with no debugger, take care :)
  */
 #include <stdio.h>
 #include <string.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdarg.h>
 #include "config.h"
 #include "errors.h"
 #include "util.h"
+extern volatile int cli_errno;
 /* some platforms do not have strdup, implement it here.
  * Returns a pointer to an allocated string or NULL on failure */
 char * cli_strdup(const char *s1)
+{
     size_t len = strlen(s1) + 1;
     void *ret = malloc(len);
-    if (ret == NULL)
+    if (ret == NULL) {
+        cli_errno = CL_ENOMEM;
         return (char *) NULL;
+    }
+    cli_errno = CL_EOK;
     return (char *) memcpy(ret, s1, len);
+}
 /*
  * Take a previously allocated string (s1), re-size it to accept s2 and copy
  * the contents of s2 into s1.
  * Return -1 on failure, or the length of the copied string on success.
  */
 int cli_redup(char **s1, const char *s2)
+{
     size_t len = strlen(s2) + 1;
     if (! len)
         return -1;
     *s1 = realloc(*s1, len);
-    if (*s1 == NULL)
+    if (*s1 == NULL) {
+        cli_errno = CL_ENOMEM;
         return -1;
+    }
     memset(*s1, 0, sizeof(*s1));
     memcpy(*s1, s2, len);
+    cli_errno = CL_EOK;
     return (int) len;
+}
-/* An asprintf() for concantenating paths. Allocates the system PATH_MAX value,
+/* An asprintf() for formatting paths, similar to asprintf() but ensures
+ * the returned allocated string is <= PATH_MAX. On failure, an attempt
+ * is made to return the original string (if not null) unmodified.
+ *
- * expands the formatted string and re-sizes the block s1 points to accordingly.
+ * Returns: Length of the new string on success, 0 if the string was handed
+ * back unmodified, -1 on failure. On failure, cli_errno is set.
+ *
- * Returns the length of the new s1 on success, -1 on failure. On failure, an
+ * We do not use POSIX_PATH_MAX, as it is typically much smaller than the
- * attempt is made to return s1 unmodified for sanity, in this case 0 is returned.
- * to indicate that s1 was not modified.
+ * PATH_MAX defined by the kernel.
+ *
+ * Use this like:
- * FIXME: ugly hack to get around asprintf(), if you use this, CHECK ITS VALUE! */
+ * if (1 > cli_psprintf(&char, "%s/%s", foo, bar)) {
+ *   cli_error(cli_errno, "Failed to format path");
+ *   stop_what_your_doing_as_your_out_of_memory();
+ * }
+ */
 int cli_psprintf(char **s1, const char *fmt, ...)
+{
     va_list ap;
     size_t needed, base = PATH_MAX + 1;
+    int skipped = 0;
+    char *orig = NULL;
     char *tmp = (char *) malloc(base);
+    /* Don't even touch s1, not enough memory */
-    if (NULL == tmp)
+    if (NULL == tmp) {
+        cli_errno = CL_ENOMEM;
         return -1;
+    }
+    /* If re-allocating s1, save a copy in case we fail */
-    char *orig = *s1;
+    if (NULL != *s1)
+        orig = cli_strdup(*s1);
+    /* Print the string to tmp so we can determine the size that
+     * we actually need */
     memset(tmp, 0, sizeof(tmp));
     va_start(ap, fmt);
+    /* vsnprintf will return the # of bytes not written */
-    vsnprintf(tmp, base, fmt, ap);
+    skipped = vsnprintf(tmp, base, fmt, ap);
     va_end(ap);
+    /* realloc/alloc s1 to be just the size that we need */
     needed = strlen(tmp) + 1;
     *s1 = realloc(*s1, needed);
     if (NULL == *s1) {
+        /* No string lived here previously, or we failed to
+         * make a copy of it, either way there's nothing we
+         * can do. */
+        if (NULL == *orig) {
+            cli_errno = CL_ENOMEM;
+            return -1;
+        }
+        /* We can't even allocate enough size to restore the
+         * saved copy, just give up */
         *s1 = realloc(*s1, strlen(orig) + 1);
         if (NULL == *s1) {
             free(tmp);
+            free(orig);
+            cli_errno = CL_ENOMEM;
             return -1;
+        }
+        /* Give the string back as we found it */
         memset(*s1, 0, sizeof(*s1));
         memcpy(*s1, orig, strlen(orig) + 1);
         free(tmp);
+        free(orig);
+        cli_errno = CL_ENOMEM;
         return 0;
+    }
+    /* Ok, great, we have enough room */
     memset(*s1, 0, sizeof(*s1));
     memcpy(*s1, tmp, needed);
     free(tmp);
+    /* Free tmp only if s1 was reallocated instead of allocated */
+    if (NULL != orig)
+        free(orig);
+    if (skipped) {
+        /* s1 was bigger than PATH_MAX when expanded, however part
+         * of the string was printed. Tell the caller not to use it */
+        cli_errno = CL_ETOOBIG;
+        return -1;
+    }
+    /* Success! */
+    cli_errno = CL_EOK;
     return (int) needed;
+}
 /* Ported from FBSD strtok.c 8.1 (Berkeley) 6/4/93 */
 char * cli_strtok_r(char *s, const char *delim, char **last)
+{
     char *spanp, *tok;
     int c, sc;
-    if (s == NULL && (s = *last) == NULL)
+    if (s == NULL && (s = *last) == NULL) {
+        cli_errno = CL_EFAIL;
         return (NULL);
+    }
 cont:
     c = *s++;
     for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
         if (c == sc)
             goto cont;
+    }
     if (c == 0) {       /* no non-delimiter characters */
         *last = NULL;
         return (NULL);
+    }
     tok = s - 1;
     for (;;) {
         c = *s++;
         spanp = (char *)delim;
         do {
             if ((sc = *spanp++) == c) {
                 if (c == 0)
                     s = NULL;
                 else
                     s[-1] = '\0';
                 *last = s;
                 return (tok);
+            }
         } while (sc != 0);
+    }
+}
 /* Ported from FBSD strtok.c 8.1 (Berkeley) 6/4/93 */
 char * cli_strtok(char *s, const char *delim)
+{
     static char *last;
     return (cli_strtok_r(s, delim, &last));
+}

Subversion Repositories HelenOS

(root)/trunk/uspace/app/bdsh/util.c – Rev 3346 → 3366