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[PATCH 06/18] posix: Remove glob GET_LOGIN_NAME_MAX usage
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Fri, 11 Aug 2017 11:50:32 -0300
- Subject: [PATCH 06/18] posix: Remove glob GET_LOGIN_NAME_MAX usage
- Authentication-results: sourceware.org; auth=none
- References: <1502463044-4042-1-git-send-email-adhemerval.zanella@linaro.org>
Current glob implementation allows non limited user name for home
directory construction on GLOB_TILDE case. To accomplish it glob
either construct a name on stack if size are small enough (based
on current alloca_used) value in heap otherwise.
There is no actual login to resize the buffer in case of the resizing
the buffer in case of ERANGE, so a static buffer using glibc default
LOGIN_NAME_MAX is suffice.
Checked on x86_64-linux-gnu.
* posix/glob.c (LOGIN_NAME_MAX): Define if not defined.
(glob): Use static buffer for user_name on getlogin_r.
---
posix/glob.c | 36 +++++-------------------------------
1 file changed, 5 insertions(+), 31 deletions(-)
diff --git a/posix/glob.c b/posix/glob.c
index 99e9c54..3a74758 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -91,10 +91,8 @@
#include <glob_internal.h>
#include <scratch_buffer.h>
-#ifdef _SC_LOGIN_NAME_MAX
-# define GET_LOGIN_NAME_MAX() sysconf (_SC_LOGIN_NAME_MAX)
-#else
-# define GET_LOGIN_NAME_MAX() (-1)
+#ifndef LOGIN_NAME_MAX
+# define LOGIN_NAME_MAX 256
#endif
static const char *next_brace_sub (const char *begin, int flags) __THROWNL;
@@ -667,28 +665,9 @@ glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
if (home_dir == NULL || home_dir[0] == '\0')
{
int success;
- char *name;
- int malloc_name = 0;
- size_t buflen = GET_LOGIN_NAME_MAX () + 1;
-
- if (buflen == 0)
- /* `sysconf' does not support _SC_LOGIN_NAME_MAX. Try
- a moderate value. */
- buflen = 20;
- if (glob_use_alloca (alloca_used, buflen))
- name = alloca_account (buflen, alloca_used);
- else
- {
- name = malloc (buflen);
- if (name == NULL)
- {
- retval = GLOB_NOSPACE;
- goto out;
- }
- malloc_name = 1;
- }
+ char user_name[LOGIN_NAME_MAX];
- success = __getlogin_r (name, buflen) == 0;
+ success = __getlogin_r (user_name, sizeof (user_name)) == 0;
if (success)
{
struct passwd *p;
@@ -698,7 +677,7 @@ glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
struct scratch_buffer pwtmpbuf;
scratch_buffer_init (&pwtmpbuf);
- while (getpwnam_r (name, &pwbuf,
+ while (getpwnam_r (user_name, &pwbuf,
pwtmpbuf.data, pwtmpbuf.length, &p)
!= 0)
{
@@ -730,11 +709,6 @@ glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
}
scratch_buffer_free (&pwtmpbuf);
}
- else
- {
- if (__glibc_unlikely (malloc_name))
- free (name);
- }
}
if (home_dir == NULL || home_dir[0] == '\0')
{
--
2.7.4