[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH 2/8] posix: Use char_array for internal glob dirname
|
From: |
Adhemerval Zanella |
|
Subject: |
[PATCH 2/8] posix: Use char_array for internal glob dirname |
|
Date: |
Tue, 5 Jan 2021 15:58:14 -0300 |
This is the first patch of the set to remove alloca usage on glob
implementation. Internal path to search for file might expand to a
non static directory derived from pattern for some difference cases
(GLOB_NOESCAPE, GNU GLOB_TILDE) and to allow a non-static dirname
path glob uses a lot of boilerplate code to manage the buffer (which
is either allocated using alloca or malloc depending both to size
requested and the total alloca_used).
The patch changes to use the char_array struct with the default size
(256 bytes). It simplifies all the allocation code by using char_array
one and every internal buffer access is done using char_array provided
functions. No functional changes are expected.
Checked on x86_64-linux-gnu.
---
posix/glob.c | 275 +++++++++++++++++++++------------------------------
1 file changed, 111 insertions(+), 164 deletions(-)
diff --git a/posix/glob.c b/posix/glob.c
index 32c88e5d15..8c6e1914c5 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -85,6 +85,7 @@
#include <flexmember.h>
#include <glob_internal.h>
#include <scratch_buffer.h>
+#include <malloc/char_array-skeleton.c>
static const char *next_brace_sub (const char *begin, int flags) __THROWNL;
@@ -298,16 +299,15 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
glob_t *pglob)
{
const char *filename;
- char *dirname = NULL;
size_t dirlen;
int status;
size_t oldcount;
int meta;
- int dirname_modified;
- int malloc_dirname = 0;
glob_t dirs;
int retval = 0;
size_t alloca_used = 0;
+ struct char_array dirname;
+ bool dirname_modified;
if (pattern == NULL || pglob == NULL || (flags & ~__GLOB_FLAGS) != 0)
{
@@ -315,6 +315,10 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
return -1;
}
+ /* Default char array is stack allocated, so there is no need to check
+ if setting the initial '\0' succeeds. */
+ char_array_init_empty (&dirname);
+
/* POSIX requires all slashes to be matched. This means that with
a trailing slash we must match only directories. */
if (pattern[0] && pattern[strlen (pattern) - 1] == '/')
@@ -335,12 +339,12 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
size_t i;
if (pglob->gl_offs >= ~((size_t) 0) / sizeof (char *))
- return GLOB_NOSPACE;
+ goto err_nospace;
pglob->gl_pathv = (char **) malloc ((pglob->gl_offs + 1)
* sizeof (char *));
if (pglob->gl_pathv == NULL)
- return GLOB_NOSPACE;
+ goto err_nospace;
for (i = 0; i <= pglob->gl_offs; ++i)
pglob->gl_pathv[i] = NULL;
@@ -392,7 +396,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
{
onealt = malloc (pattern_len);
if (onealt == NULL)
- return GLOB_NOSPACE;
+ goto err_nospace;
}
/* We know the prefix for all sub-patterns. */
@@ -454,7 +458,8 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
globfree (pglob);
pglob->gl_pathc = 0;
}
- return result;
+ retval = result;
+ goto out;
}
if (*next == '}')
@@ -471,9 +476,10 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
if (pglob->gl_pathc != firstc)
/* We found some entries. */
- return 0;
+ retval = 0;
else if (!(flags & (GLOB_NOCHECK|GLOB_NOMAGIC)))
- return GLOB_NOMATCH;
+ retval = GLOB_NOMATCH;
+ goto out;
}
}
@@ -492,14 +498,15 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
filename = strchr (pattern, ':');
#endif /* __MSDOS__ || WINDOWS32 */
- dirname_modified = 0;
+ dirname_modified = false;
if (filename == NULL)
{
/* This can mean two things: a simple name or "~name". The latter
case is nothing but a notation for a directory. */
if ((flags & (GLOB_TILDE|GLOB_TILDE_CHECK)) && pattern[0] == '~')
{
- dirname = (char *) pattern;
+ if (!char_array_set_str (&dirname, pattern))
+ goto err_nospace;
dirlen = strlen (pattern);
/* Set FILENAME to NULL as a special flag. This is ugly but
@@ -516,7 +523,8 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
}
filename = pattern;
- dirname = (char *) ".";
+ if (!char_array_set_str (&dirname, "."))
+ goto err_nospace;
dirlen = 0;
}
}
@@ -525,13 +533,13 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
&& (flags & GLOB_NOESCAPE) == 0))
{
/* "/pattern" or "\\/pattern". */
- dirname = (char *) "/";
+ if (!char_array_set_str (&dirname, "/"))
+ goto err_nospace;
dirlen = 1;
++filename;
}
else
{
- char *newp;
dirlen = filename - pattern;
#if defined __MSDOS__ || defined WINDOWS32
if (*filename == ':'
@@ -545,31 +553,26 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
/* For now, disallow wildcards in the drive spec, to
prevent infinite recursion in glob. */
if (__glob_pattern_p (drive_spec, !(flags & GLOB_NOESCAPE)))
- return GLOB_NOMATCH;
+ {
+ retval = GLOB_NOMATCH;
+ goto out;
+ }
/* If this is "d:pattern", we need to copy ':' to DIRNAME
as well. If it's "d:/pattern", don't remove the slash
from "d:/", since "d:" and "d:/" are not the same.*/
}
#endif
- if (glob_use_alloca (alloca_used, dirlen + 1))
- newp = alloca_account (dirlen + 1, alloca_used);
- else
- {
- newp = malloc (dirlen + 1);
- if (newp == NULL)
- return GLOB_NOSPACE;
- malloc_dirname = 1;
- }
- *((char *) mempcpy (newp, pattern, dirlen)) = '\0';
- dirname = newp;
+ if (!char_array_set_str_size (&dirname, pattern, dirlen))
+ goto err_nospace;
++filename;
#if defined __MSDOS__ || defined WINDOWS32
bool drive_root = (dirlen > 1
- && (dirname[dirlen - 1] == ':'
- || (dirlen > 2 && dirname[dirlen - 2] == ':'
- && dirname[dirlen - 1] == '/')));
+ && (char_array_pos (&dirname, dirlen - 1) != ':'
+ || (dirlen > 2
+ && char_array_pos (&dirname, dirlen - 2) != ':'
+ && char_array_pos (&dirname, dirlen - 1) !=
'/')));
#else
bool drive_root = false;
#endif
@@ -578,20 +581,24 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
/* "pattern/". Expand "pattern", appending slashes. */
{
int orig_flags = flags;
- if (!(flags & GLOB_NOESCAPE) && dirname[dirlen - 1] == '\\')
+ if (!(flags & GLOB_NOESCAPE)
+ && char_array_pos (&dirname, dirlen - 1) == '\\')
{
/* "pattern\\/". Remove the final backslash if it hasn't
been quoted. */
- char *p = (char *) &dirname[dirlen - 1];
-
- while (p > dirname && p[-1] == '\\') --p;
- if ((&dirname[dirlen] - p) & 1)
+ size_t p = dirlen - 1;
+ while (p > 0 && char_array_pos (&dirname, p - 1) == '\\') --p;
+ if ((dirlen - p) & 1)
{
- *(char *) &dirname[--dirlen] = '\0';
+ /* Since we are shrinking the array, there is no need to
+ check the function return. */
+ dirlen -= 1;
+ char_array_crop (&dirname, dirlen);
flags &= ~(GLOB_NOCHECK | GLOB_NOMAGIC);
}
}
- int val = __glob (dirname, flags | GLOB_MARK, errfunc, pglob);
+ int val = __glob (char_array_str (&dirname), flags | GLOB_MARK,
+ errfunc, pglob);
if (val == 0)
pglob->gl_flags = ((pglob->gl_flags & ~GLOB_MARK)
| (flags & GLOB_MARK));
@@ -608,11 +615,14 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
}
}
- if ((flags & (GLOB_TILDE|GLOB_TILDE_CHECK)) && dirname[0] == '~')
+ if ((flags & (GLOB_TILDE|GLOB_TILDE_CHECK))
+ && char_array_pos (&dirname, 0) == '~')
{
- if (dirname[1] == '\0' || dirname[1] == '/'
- || (!(flags & GLOB_NOESCAPE) && dirname[1] == '\\'
- && (dirname[2] == '\0' || dirname[2] == '/')))
+ if (char_array_pos (&dirname, 1) == '\0'
+ || char_array_pos (&dirname, 1) == '/'
+ || (!(flags & GLOB_NOESCAPE) && char_array_pos (&dirname, 1) == '\\'
+ && (char_array_pos (&dirname, 2) == '\0'
+ || char_array_pos (&dirname, 2) == '/')))
{
/* Look up home directory. */
char *home_dir = getenv ("HOME");
@@ -663,10 +673,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
if (err != ERANGE)
break;
if (!scratch_buffer_grow (&s))
- {
- retval = GLOB_NOSPACE;
- goto out;
- }
+ goto err_nospace;
}
if (err == 0)
{
@@ -675,10 +682,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
}
scratch_buffer_free (&s);
if (err == 0 && home_dir == NULL)
- {
- retval = GLOB_NOSPACE;
- goto out;
- }
+ goto err_nospace;
#endif /* WINDOWS32 */
}
if (home_dir == NULL || home_dir[0] == '\0')
@@ -697,53 +701,26 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
}
}
/* Now construct the full directory. */
- if (dirname[1] == '\0')
+ if (char_array_pos (&dirname, 1) == '\0')
{
- if (__glibc_unlikely (malloc_dirname))
- free (dirname);
-
- dirname = home_dir;
- dirlen = strlen (dirname);
- malloc_dirname = malloc_home_dir;
+ if (!char_array_set_str (&dirname, home_dir))
+ goto err_nospace;
+ dirlen = char_array_size (&dirname) - 1;
}
else
{
- char *newp;
- size_t home_len = strlen (home_dir);
- int use_alloca = glob_use_alloca (alloca_used, home_len +
dirlen);
- if (use_alloca)
- newp = alloca_account (home_len + dirlen, alloca_used);
- else
- {
- newp = malloc (home_len + dirlen);
- if (newp == NULL)
- {
- if (__glibc_unlikely (malloc_home_dir))
- free (home_dir);
- retval = GLOB_NOSPACE;
- goto out;
- }
- }
-
- mempcpy (mempcpy (newp, home_dir, home_len),
- &dirname[1], dirlen);
-
- if (__glibc_unlikely (malloc_dirname))
- free (dirname);
-
- dirname = newp;
- dirlen += home_len - 1;
- malloc_dirname = !use_alloca;
-
- if (__glibc_unlikely (malloc_home_dir))
- free (home_dir);
+ /* Replaces '~' by the obtained HOME dir. */
+ char_array_erase (&dirname, 0);
+ if (!char_array_prepend_str (&dirname, home_dir))
+ goto err_nospace;
}
- dirname_modified = 1;
+ dirname_modified = true;
}
else
{
#ifndef WINDOWS32
- char *end_name = strchr (dirname, '/');
+ char *dirnamestr = char_array_at (&dirname, 0);
+ char *end_name = strchr (dirnamestr, '/');
char *user_name;
int malloc_user_name = 0;
char *unescape = NULL;
@@ -752,23 +729,23 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
{
if (end_name == NULL)
{
- unescape = strchr (dirname, '\\');
+ unescape = strchr (dirnamestr, '\\');
if (unescape)
end_name = strchr (unescape, '\0');
}
else
- unescape = memchr (dirname, '\\', end_name - dirname);
+ unescape = memchr (dirnamestr, '\\', end_name - dirnamestr);
}
if (end_name == NULL)
- user_name = dirname + 1;
+ user_name = dirnamestr + 1;
else
{
char *newp;
- if (glob_use_alloca (alloca_used, end_name - dirname))
- newp = alloca_account (end_name - dirname, alloca_used);
+ if (glob_use_alloca (alloca_used, end_name - dirnamestr))
+ newp = alloca_account (end_name - dirnamestr, alloca_used);
else
{
- newp = malloc (end_name - dirname);
+ newp = malloc (end_name - dirnamestr);
if (newp == NULL)
{
retval = GLOB_NOSPACE;
@@ -778,8 +755,8 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
}
if (unescape != NULL)
{
- char *p = mempcpy (newp, dirname + 1,
- unescape - dirname - 1);
+ char *p = mempcpy (newp, dirnamestr + 1,
+ unescape - dirnamestr - 1);
char *q = unescape;
while (q != end_name)
{
@@ -801,8 +778,9 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
*p = '\0';
}
else
- *((char *) mempcpy (newp, dirname + 1, end_name - dirname - 1))
- = '\0';
+ *((char *) mempcpy (newp, dirnamestr + 1,
+ end_name - dirnamestr - 1))
+ = '\0';
user_name = newp;
}
@@ -835,39 +813,14 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
/* If we found a home directory use this. */
if (p != NULL)
{
- size_t home_len = strlen (p->pw_dir);
- size_t rest_len = end_name == NULL ? 0 : strlen (end_name);
- /* dirname contains end_name; we can't free it now. */
- char *prev_dirname =
- (__glibc_unlikely (malloc_dirname) ? dirname : NULL);
- char *d;
-
- malloc_dirname = 0;
-
- if (glob_use_alloca (alloca_used, home_len + rest_len + 1))
- dirname = alloca_account (home_len + rest_len + 1,
- alloca_used);
- else
+ if (!char_array_set_str (&dirname, p->pw_dir))
{
- dirname = malloc (home_len + rest_len + 1);
- if (dirname == NULL)
- {
- free (prev_dirname);
- scratch_buffer_free (&pwtmpbuf);
- retval = GLOB_NOSPACE;
- goto out;
- }
- malloc_dirname = 1;
+ scratch_buffer_free (&pwtmpbuf);
+ goto err_nospace;
}
- d = mempcpy (dirname, p->pw_dir, home_len);
- if (end_name != NULL)
- d = mempcpy (d, end_name, rest_len);
- *d = '\0';
-
- free (prev_dirname);
- dirlen = home_len + rest_len;
- dirname_modified = 1;
+ dirlen = strlen (p->pw_dir);
+ dirname_modified = true;
}
else
{
@@ -908,37 +861,33 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
goto nospace;
pglob->gl_pathv = new_gl_pathv;
- if (flags & GLOB_MARK && is_dir (dirname, flags, pglob))
+ if (flags & GLOB_MARK
+ && is_dir (char_array_str (&dirname), flags, pglob))
{
char *p;
pglob->gl_pathv[newcount] = malloc (dirlen + 2);
if (pglob->gl_pathv[newcount] == NULL)
goto nospace;
- p = mempcpy (pglob->gl_pathv[newcount], dirname, dirlen);
+ p = mempcpy (pglob->gl_pathv[newcount],
+ char_array_str (&dirname), dirlen);
p[0] = '/';
p[1] = '\0';
- if (__glibc_unlikely (malloc_dirname))
- free (dirname);
}
else
{
- if (__glibc_unlikely (malloc_dirname))
- pglob->gl_pathv[newcount] = dirname;
- else
- {
- pglob->gl_pathv[newcount] = strdup (dirname);
- if (pglob->gl_pathv[newcount] == NULL)
- goto nospace;
- }
+ pglob->gl_pathv[newcount] = strdup (char_array_str (&dirname));
+ if (pglob->gl_pathv[newcount] == NULL)
+ goto nospace;
}
pglob->gl_pathv[++newcount] = NULL;
++pglob->gl_pathc;
pglob->gl_flags = flags;
- return 0;
+ goto out;
}
- meta = __glob_pattern_type (dirname, !(flags & GLOB_NOESCAPE));
+ meta = __glob_pattern_type (char_array_str (&dirname),
+ !(flags & GLOB_NOESCAPE));
/* meta is 1 if correct glob pattern containing metacharacters.
If meta has bit (1 << 2) set, it means there was an unterminated
[ which we handle the same, using fnmatch. Broken unterminated
@@ -951,15 +900,15 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
the pattern in each directory found. */
size_t i;
- if (!(flags & GLOB_NOESCAPE) && dirlen > 0 && dirname[dirlen - 1] ==
'\\')
+ if (!(flags & GLOB_NOESCAPE) && dirlen > 0
+ && char_array_pos (&dirname, dirlen - 1) == '\\')
{
/* "foo\\/bar". Remove the final backslash from dirname
if it has not been quoted. */
- char *p = (char *) &dirname[dirlen - 1];
-
- while (p > dirname && p[-1] == '\\') --p;
- if ((&dirname[dirlen] - p) & 1)
- *(char *) &dirname[--dirlen] = '\0';
+ size_t p = dirlen - 1;
+ while (p > 0 && char_array_pos (&dirname, p - 1) == '\\') --p;
+ if ((dirlen - p) & 1)
+ char_array_crop (&dirname, --dirlen);
}
if (__glibc_unlikely ((flags & GLOB_ALTDIRFUNC) != 0))
@@ -973,7 +922,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
dirs.gl_lstat = pglob->gl_lstat;
}
- status = __glob (dirname,
+ status = __glob (char_array_str (&dirname),
((flags & (GLOB_ERR | GLOB_NOESCAPE | GLOB_ALTDIRFUNC))
| GLOB_NOSORT | GLOB_ONLYDIR),
errfunc, &dirs);
@@ -1020,8 +969,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
globfree (&dirs);
globfree (pglob);
pglob->gl_pathc = 0;
- retval = GLOB_NOSPACE;
- goto out;
+ goto err_nospace;
}
}
@@ -1043,8 +991,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
{
nospace2:
globfree (&dirs);
- retval = GLOB_NOSPACE;
- goto out;
+ goto err_nospace;
}
new_gl_pathv = realloc (pglob->gl_pathv,
@@ -1059,8 +1006,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
globfree (&dirs);
globfree (pglob);
pglob->gl_pathc = 0;
- retval = GLOB_NOSPACE;
- goto out;
+ goto err_nospace;
}
++pglob->gl_pathc;
@@ -1086,7 +1032,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
if (meta & GLOBPAT_BACKSLASH)
{
- char *p = strchr (dirname, '\\'), *q;
+ 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. */
@@ -1103,12 +1049,12 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
++q;
}
while (*p++ != '\0');
- dirname_modified = 1;
+ dirname_modified = true;
}
if (dirname_modified)
flags &= ~(GLOB_NOCHECK | GLOB_NOMAGIC);
- status = glob_in_dir (filename, dirname, flags, errfunc, pglob,
- alloca_used);
+ status = glob_in_dir (filename, char_array_str (&dirname), flags,
+ errfunc, pglob, alloca_used);
if (status != 0)
{
if (status == GLOB_NOMATCH && flags != orig_flags
@@ -1126,14 +1072,13 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
if (dirlen > 0)
{
/* Stick the directory on the front of each name. */
- if (prefix_array (dirname,
+ if (prefix_array (char_array_str (&dirname),
&pglob->gl_pathv[old_pathc + pglob->gl_offs],
pglob->gl_pathc - old_pathc))
{
globfree (pglob);
pglob->gl_pathc = 0;
- retval = GLOB_NOSPACE;
- goto out;
+ goto err_nospace;
}
}
}
@@ -1152,8 +1097,7 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
{
globfree (pglob);
pglob->gl_pathc = 0;
- retval = GLOB_NOSPACE;
- goto out;
+ goto err_nospace;
}
strcpy (&new[len - 2], "/");
pglob->gl_pathv[i] = new;
@@ -1169,10 +1113,13 @@ __glob (const char *pattern, int flags, int (*errfunc)
(const char *, int),
}
out:
- if (__glibc_unlikely (malloc_dirname))
- free (dirname);
+ char_array_free (&dirname);
return retval;
+
+ err_nospace:
+ char_array_free (&dirname);
+ return GLOB_NOSPACE;
}
#if defined _LIBC && !defined __glob
versioned_symbol (libc, __glob, glob, GLIBC_2_27);
--
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 <=
- [PATCH 6/8] posix: Remove alloca usage on glob user_name, Adhemerval Zanella, 2021/01/05
- [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