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[PATCH 21/25] wordexp: Rewrite parse_tilde to use struct scratch_buffer
- From: Florian Weimer <fweimer at redhat dot com>
- To: libc-alpha at sourceware dot org
- Date: Sun, 1 Mar 2015 19:48:31 +0100
- Subject: [PATCH 21/25] wordexp: Rewrite parse_tilde to use struct scratch_buffer
- Authentication-results: sourceware.org; auth=none
- References: <cover dot 1425285061 dot git dot fweimer at redhat dot com>
---
posix/wordexp.c | 46 +++++++++++++++++++++++++++++-----------------
1 file changed, 29 insertions(+), 17 deletions(-)
diff --git a/posix/wordexp.c b/posix/wordexp.c
index e3d8d6b..cf5801a 100644
--- a/posix/wordexp.c
+++ b/posix/wordexp.c
@@ -17,7 +17,6 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-#include <alloca.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
@@ -41,6 +40,7 @@
#include <wchar.h>
#include <wordexp.h>
#include <kernel-features.h>
+#include <scratch_buffer.h>
#include <bits/libc-lock.h>
#include <_itoa.h>
@@ -308,12 +308,7 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length,
if (i == 1 + *offset)
{
/* Tilde appears on its own */
- uid_t uid;
- struct passwd pwd, *tpwd;
- int buflen = 1000;
char* home;
- char* buffer;
- int result;
/* POSIX.2 says ~ expands to $HOME and if HOME is unset the
results are unspecified. We do a lookup on the uid if
@@ -328,25 +323,38 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length,
}
else
{
- uid = __getuid ();
- buffer = __alloca (buflen);
-
- while ((result = __getpwuid_r (uid, &pwd, buffer, buflen, &tpwd)) != 0
+ struct passwd pwd, *tpwd;
+ uid_t uid = __getuid ();
+ int result;
+ struct scratch_buffer tmpbuf;
+ scratch_buffer_init (&tmpbuf);
+
+ while ((result = __getpwuid_r (uid, &pwd,
+ tmpbuf.data, tmpbuf.length,
+ &tpwd)) != 0
&& errno == ERANGE)
- buffer = extend_alloca (buffer, buflen, buflen + 1000);
+ if (!scratch_buffer_grow (&tmpbuf))
+ return WRDE_NOSPACE;
if (result == 0 && tpwd != NULL && pwd.pw_dir != NULL)
{
*word = w_addstr (*word, word_length, max_length, pwd.pw_dir);
if (*word == NULL)
- return WRDE_NOSPACE;
+ {
+ scratch_buffer_free (&tmpbuf);
+ return WRDE_NOSPACE;
+ }
}
else
{
*word = w_addchar (*word, word_length, max_length, '~');
if (*word == NULL)
- return WRDE_NOSPACE;
+ {
+ scratch_buffer_free (&tmpbuf);
+ return WRDE_NOSPACE;
+ }
}
+ scratch_buffer_free (&tmpbuf);
}
}
else
@@ -354,13 +362,15 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length,
/* Look up user name in database to get home directory */
char *user = strndupa (&words[1 + *offset], i - (1 + *offset));
struct passwd pwd, *tpwd;
- int buflen = 1000;
- char* buffer = __alloca (buflen);
int result;
+ struct scratch_buffer tmpbuf;
+ scratch_buffer_init (&tmpbuf);
- while ((result = __getpwnam_r (user, &pwd, buffer, buflen, &tpwd)) != 0
+ while ((result = __getpwnam_r (user, &pwd, tmpbuf.data, tmpbuf.length,
+ &tpwd)) != 0
&& errno == ERANGE)
- buffer = extend_alloca (buffer, buflen, buflen + 1000);
+ if (!scratch_buffer_grow (&tmpbuf))
+ return WRDE_NOSPACE;
if (result == 0 && tpwd != NULL && pwd.pw_dir)
*word = w_addstr (*word, word_length, max_length, pwd.pw_dir);
@@ -372,6 +382,8 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length,
*word = w_addstr (*word, word_length, max_length, user);
}
+ scratch_buffer_free (&tmpbuf);
+
*offset = i - 1;
}
return *word ? 0 : WRDE_NOSPACE;
--
2.1.0