[src/trunk]: src/lib/librumphijack hijack __getcwd()

[pooka <pooka%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/35db77d79d96
branches:  trunk
changeset: 762326:35db77d79d96
user:      pooka <pooka%NetBSD.org@localhost>
date:      Sat Feb 19 13:10:35 2011 +0000

description:
hijack __getcwd()

diffstat:

 lib/librumphijack/hijack.c |  60 ++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 58 insertions(+), 2 deletions(-)

diffs (111 lines):

diff -r a4cbcb902464 -r 35db77d79d96 lib/librumphijack/hijack.c
--- a/lib/librumphijack/hijack.c        Sat Feb 19 13:09:40 2011 +0000
+++ b/lib/librumphijack/hijack.c        Sat Feb 19 13:10:35 2011 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: hijack.c,v 1.56 2011/02/19 13:09:40 pooka Exp $       */
+/*      $NetBSD: hijack.c,v 1.57 2011/02/19 13:10:35 pooka Exp $       */
 
 /*-
  * Copyright (c) 2011 Antti Kantee.  All Rights Reserved.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: hijack.c,v 1.56 2011/02/19 13:09:40 pooka Exp $");
+__RCSID("$NetBSD: hijack.c,v 1.57 2011/02/19 13:10:35 pooka Exp $");
 
 #define __ssp_weak_name(fun) _hijack_ ## fun
 
@@ -87,6 +87,7 @@
        DUALCALL_TRUNCATE, DUALCALL_FTRUNCATE,
        DUALCALL_FSYNC, DUALCALL_FSYNC_RANGE,
        DUALCALL_MOUNT, DUALCALL_UNMOUNT,
+       DUALCALL___GETCWD,
        DUALCALL__NUM
 };
 
@@ -138,6 +139,7 @@
 int REALFUTIMES(int, const struct timeval [2]);
 int REALMOUNT(const char *, const char *, int, void *, size_t);
 off_t REALLSEEK(int, off_t, int);
+int __getcwd(char *, size_t);
 
 #define S(a) __STRING(a)
 struct sysnames {
@@ -200,6 +202,7 @@
        { DUALCALL_FSYNC_RANGE, "fsync_range",  RSYS_NAME(FSYNC_RANGE)  },
        { DUALCALL_MOUNT,       S(REALMOUNT),   RSYS_NAME(MOUNT)        },
        { DUALCALL_UNMOUNT,     "unmount",      RSYS_NAME(UNMOUNT)      },
+       { DUALCALL___GETCWD,    "__getcwd",     RSYS_NAME(__GETCWD)     },
 };
 #undef S
 
@@ -376,8 +379,15 @@
 pathparser(char *buf)
 {
 
+       /* sanity-check */
        if (*buf != '/')
                errx(1, "hijack path specifier must begin with ``/''");
+       rumpprefixlen = strlen(buf);
+       if (rumpprefixlen < 2)
+               errx(1, "invalid hijack prefix: %s", buf);
+       if (buf[rumpprefixlen-1] == '/' && strspn(buf, "/") != rumpprefixlen)
+               errx(1, "hijack prefix may end in slash only if pure "
+                   "slash, gave %s", buf);
 
        if ((rumpprefix = strdup(buf)) == NULL)
                err(1, "strdup");
@@ -698,6 +708,52 @@
 }
 
 int
+__getcwd(char *bufp, size_t len)
+{
+       int (*op___getcwd)(char *, size_t);
+       int rv;
+
+       if (pwdinrump) {
+               size_t prefixgap;
+               bool iamslash;
+
+               if (rumpprefix[rumpprefixlen-1] == '/')
+                       iamslash = true;
+               else
+                       iamslash = false;
+
+               if (iamslash)
+                       prefixgap = rumpprefixlen - 1; /* ``//+path'' */
+               else
+                       prefixgap = rumpprefixlen; /* ``/pfx+/path'' */
+               if (len <= prefixgap) {
+                       return ERANGE;
+               }
+
+               op___getcwd = GETSYSCALL(rump, __GETCWD);
+               rv = op___getcwd(bufp + prefixgap, len - prefixgap);
+               if (rv == -1)
+                       return rv;
+
+               /* augment the "/" part only for a non-root path */
+               memcpy(bufp, rumpprefix, rumpprefixlen);
+
+               /* append / only to non-root cwd */
+               if (rv != 2)
+                       bufp[prefixgap] = '/';
+
+               /* don't append extra slash in the purely-slash case */
+               if (rv == 2 && !iamslash)
+                       bufp[rumpprefixlen] = '\0';
+
+               return rv;
+       } else {
+               op___getcwd = GETSYSCALL(host, __GETCWD);
+               return op___getcwd(bufp, len);
+       }
+}
+
+int
 rename(const char *from, const char *to)
 {
        int (*op_rename)(const char *, const char *);