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[PATCH 6/8] posix: Remove alloca usage on glob user_name
From: |
Adhemerval Zanella |
Subject: |
[PATCH 6/8] posix: Remove alloca usage on glob user_name |
Date: |
Tue, 5 Jan 2021 15:58:18 -0300 |
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 | 86 ++++++++++++++++------------------------------------
1 file changed, 26 insertions(+), 60 deletions(-)
diff --git a/posix/glob.c b/posix/glob.c
index d199204931..c126b4501d 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -42,13 +42,13 @@
#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
@@ -215,29 +215,6 @@ 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 7 <= __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);
@@ -724,11 +701,10 @@ __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))
{
@@ -742,27 +718,19 @@ __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 == '\\')
@@ -773,20 +741,21 @@ __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. */
@@ -798,7 +767,7 @@ __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)
{
@@ -809,11 +778,10 @@ __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)
@@ -1038,9 +1006,7 @@ __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
{
--
2.25.1
- [PATCH 0/8] Remove alloca usage from glob, Adhemerval Zanella, 2021/01/05
- [PATCH 1/8] malloc: Add specialized dynarray for C strings, Adhemerval Zanella, 2021/01/05
- [PATCH 3/8] posix: Remove alloca usage for GLOB_BRACE on glob, Adhemerval Zanella, 2021/01/05
- [PATCH 4/8] posix: Remove alloca usage on glob dirname, Adhemerval Zanella, 2021/01/05
- [PATCH 2/8] posix: Use char_array for internal glob dirname, Adhemerval Zanella, 2021/01/05
- [PATCH 6/8] posix: Remove alloca usage on glob user_name,
Adhemerval Zanella <=
- [PATCH 5/8] posix: Use dynarray for globname in glob, Adhemerval Zanella, 2021/01/05
- [PATCH 7/8] posix: Use char_array for home_dir in glob, Adhemerval Zanella, 2021/01/05
- [PATCH 8/8] posix: Remove all alloca usage in glob, Adhemerval Zanella, 2021/01/05
- Re: [PATCH 0/8] Remove alloca usage from glob, Paul Eggert, 2021/01/13