This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
[PATCH 6/8] posix: Remove alloca usage on glob user_name
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Tue, 21 Nov 2017 11:55:28 -0200
- Subject: [PATCH 6/8] posix: Remove alloca usage on glob user_name
- Authentication-results: sourceware.org; auth=none
- References: <1511272530-10936-1-git-send-email-adhemerval.zanella@linaro.org>
This patch uses dynarray at glob internal user name manipulation for
GLOB_TILDE. It simplifies it and removes all the boilerplate buffer
managements required. It also removes the glob_use_alloca, since
it is not used anymore.
Checked on x86_64-linux-gnu.
* posix/glob.c (size_add_wrapv, glob_use_alloca): Remove.
(__glob): Use char_array for user name.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
---
ChangeLog | 3 +++
posix/glob.c | 86 ++++++++++++++++++------------------------------------------
2 files changed, 29 insertions(+), 60 deletions(-)
diff --git a/posix/glob.c b/posix/glob.c
index 59baf62..aefdb28 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -32,13 +32,13 @@
#ifndef WINDOWS32
# include <pwd.h>
+# include <alloca.h>
#endif
#include <errno.h>
#include <dirent.h>
#include <stdlib.h>
#include <string.h>
-#include <alloca.h>
#ifdef _LIBC
# undef strdup
@@ -205,29 +205,6 @@ glob_lstat (glob_t *pglob, int flags, const char *fullname)
: LSTAT64 (fullname, &ust.st64));
}
-/* Set *R = A + B. Return true if the answer is mathematically
- incorrect due to overflow; in this case, *R is the low order
- bits of the correct answer. */
-
-static bool
-size_add_wrapv (size_t a, size_t b, size_t *r)
-{
-#if 5 <= __GNUC__ && !defined __ICC
- return __builtin_add_overflow (a, b, r);
-#else
- *r = a + b;
- return *r < a;
-#endif
-}
-
-static bool
-glob_use_alloca (size_t alloca_used, size_t len)
-{
- size_t size;
- return (!size_add_wrapv (alloca_used, len, &size)
- && __libc_use_alloca (size));
-}
-
static int glob_in_dir (const char *pattern, const char *directory,
int flags, int (*errfunc) (const char *, int),
glob_t *pglob, size_t alloca_used);
@@ -712,11 +689,10 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
else
{
#ifndef WINDOWS32
- char *dirnamestr = char_array_at (&dirname, 0);
- char *end_name = strchr (dirnamestr, '/');
- char *user_name;
- int malloc_user_name = 0;
- char *unescape = NULL;
+ const char *dirnamestr = char_array_str (&dirname);
+ const char *end_name = strchr (dirnamestr, '/');
+ struct char_array user_name;
+ const char *unescape = NULL;
if (!(flags & GLOB_NOESCAPE))
{
@@ -730,27 +706,19 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
unescape = memchr (dirnamestr, '\\', end_name - dirnamestr);
}
if (end_name == NULL)
- user_name = dirnamestr + 1;
+ {
+ if (!char_array_init_str (&user_name, dirnamestr + 1))
+ goto err_nospace;
+ }
else
{
- char *newp;
- if (glob_use_alloca (alloca_used, end_name - dirnamestr))
- newp = alloca_account (end_name - dirnamestr, alloca_used);
- else
- {
- newp = malloc (end_name - dirnamestr);
- if (newp == NULL)
- {
- retval = GLOB_NOSPACE;
- goto out;
- }
- malloc_user_name = 1;
- }
if (unescape != NULL)
{
- char *p = mempcpy (newp, dirnamestr + 1,
- unescape - dirnamestr - 1);
- char *q = unescape;
+ ptrdiff_t name_len = unescape - dirnamestr - 1;
+ if (!char_array_init_str_size (&user_name, dirnamestr + 1,
+ name_len))
+ goto err_nospace;
+ const char *q = unescape;
while (q != end_name)
{
if (*q == '\\')
@@ -761,20 +729,21 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
but "~fo\\o\\/" unescape to user_name
"foo". */
if (filename == NULL)
- *p++ = '\\';
+ char_array_append_char (&user_name, '\\');
break;
}
++q;
}
- *p++ = *q++;
+ char_array_append_char (&user_name, *q++);
}
- *p = '\0';
}
else
- *((char *) mempcpy (newp, dirnamestr + 1,
- end_name - dirnamestr - 1))
- = '\0';
- user_name = newp;
+ {
+ ptrdiff_t name_len = end_name - dirnamestr - 1;
+ if (!char_array_init_str_size (&user_name, dirnamestr + 1,
+ name_len))
+ goto err_nospace;
+ }
}
/* Look up specific user's home directory. */
@@ -786,7 +755,7 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
# if defined HAVE_GETPWNAM_R || defined _LIBC
struct passwd pwbuf;
- while (getpwnam_r (user_name, &pwbuf,
+ while (getpwnam_r (char_array_str (&user_name), &pwbuf,
pwtmpbuf.data, pwtmpbuf.length, &p)
== ERANGE)
{
@@ -797,11 +766,10 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
}
}
# else
- p = getpwnam (user_name);
+ p = getpwnam (char_array_str (&user_name));
# endif
- if (__glibc_unlikely (malloc_user_name))
- free (user_name);
+ char_array_free (&user_name);
/* If we found a home directory use this. */
if (p != NULL)
@@ -1024,9 +992,7 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
if (meta & GLOBPAT_BACKSLASH)
{
char *p = strchr (char_array_str (&dirname), '\\'), *q;
- /* We need to unescape the dirname string. It is certainly
- allocated by alloca, as otherwise filename would be NULL
- or dirname wouldn't contain backslashes. */
+ /* We need to unescape the dirname string. */
q = p;
do
{
--
2.7.4