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which: fix TODO with NOFORK+malloc_failure misbehaving

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function                                             old     new   delta
find_executable                                       86     104     +18
which_main                                           202     194      -8
executable_exists                                     66      51     -15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 18/-23)             Total: -5 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-01-12 13:21:33 +01:00
parent 3bb3e1d0a1
commit cca7c611f2
4 changed files with 28 additions and 26 deletions
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16
debianutils/which.c
View File

@ -30,12 +30,15 @@
int which_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int which_main(int argc UNUSED_PARAM, char **argv)
{
const char *env_path;
char *env_path;
int status = 0;
/* This sizeof(): bb_default_root_path is shorter than BB_PATH_ROOT_PATH */
char buf[sizeof(BB_PATH_ROOT_PATH)];
env_path = getenv("PATH");
if (!env_path)
env_path = bb_default_root_path;
/* env_path must be writable, and must not alloc, so... */
env_path = strcpy(buf, bb_default_root_path);
getopt32(argv, "^" "a" "\0" "-1"/*at least one arg*/);
argv += optind;
@ -51,20 +54,17 @@ int which_main(int argc UNUSED_PARAM, char **argv)
}
} else {
char *path;
char *tmp;
char *p;
path = tmp = xstrdup(env_path);
//NOFORK FIXME: nested xmallocs (one is inside find_executable())
//can leak memory on failure
while ((p = find_executable(*argv, &tmp)) != NULL) {
path = env_path;
/* NOFORK NB: xmalloc inside find_executable(), must have no allocs above! */
while ((p = find_executable(*argv, &path)) != NULL) {
missing = 0;
puts(p);
free(p);
if (!option_mask32) /* -a not set */
break;
}
free(path);
}
status |= missing;
} while (*++argv);

12
include/libbb.h
View File

@ -2005,10 +2005,16 @@ extern const char bb_path_wtmp_file[] ALIGN1;
#define bb_dev_null "/dev/null"
extern const char bb_busybox_exec_path[] ALIGN1;
/* util-linux manpage says /sbin:/bin:/usr/sbin:/usr/bin,
* but I want to save a few bytes here */
extern const char bb_PATH_root_path[] ALIGN1; /* "PATH=/sbin:/usr/sbin:/bin:/usr/bin" */
/* allow default system PATH to be extended via CFLAGS */
#ifndef BB_ADDITIONAL_PATH
#define BB_ADDITIONAL_PATH ""
#endif
#define BB_PATH_ROOT_PATH "PATH=/sbin:/usr/sbin:/bin:/usr/bin" BB_ADDITIONAL_PATH
extern const char bb_PATH_root_path[] ALIGN1; /* BB_PATH_ROOT_PATH */
#define bb_default_root_path (bb_PATH_root_path + sizeof("PATH"))
/* util-linux manpage says /sbin:/bin:/usr/sbin:/usr/bin,
* but I want to save a few bytes here:
*/
#define bb_default_path (bb_PATH_root_path + sizeof("PATH=/sbin:/usr/sbin"))
extern const int const_int_0;

18
libbb/executable.c
View File

@ -25,7 +25,8 @@ int FAST_FUNC file_is_executable(const char *name)
* you may call find_executable again with this PATHp to continue
* (if it's not NULL).
* return NULL otherwise; (PATHp is undefined)
* in all cases (*PATHp) contents will be trashed (s/:/NUL/).
* in all cases (*PATHp) contents are temporarily modified
* but are restored on return (s/:/NUL/ and back).
*/
char* FAST_FUNC find_executable(const char *filename, char **PATHp)
{
@ -41,14 +42,17 @@ char* FAST_FUNC find_executable(const char *filename, char **PATHp)
p = *PATHp;
while (p) {
int ex;
n = strchr(p, ':');
if (n)
*n++ = '\0';
if (n) *n = '\0';
p = concat_path_file(
p[0] ? p : ".", /* handle "::" case */
filename
);
if (file_is_executable(p)) {
ex = file_is_executable(p);
if (n) *n++ = ':';
if (ex) {
*PATHp = n;
return p;
}
@ -64,10 +68,8 @@ char* FAST_FUNC find_executable(const char *filename, char **PATHp)
*/
int FAST_FUNC executable_exists(const char *filename)
{
char *path = xstrdup(getenv("PATH"));
char *tmp = path;
char *ret = find_executable(filename, &tmp);
free(path);
char *path = getenv("PATH");
char *ret = find_executable(filename, &path);
free(ret);
return ret != NULL;
}

8
libbb/messages.c
View File

@ -6,11 +6,6 @@
*/
#include "libbb.h"
/* allow default system PATH to be extended via CFLAGS */
#ifndef BB_ADDITIONAL_PATH
#define BB_ADDITIONAL_PATH ""
#endif
/* allow version to be extended, via CFLAGS */
#ifndef BB_EXTRA_VERSION
#define BB_EXTRA_VERSION " ("AUTOCONF_TIMESTAMP")"
@ -36,8 +31,7 @@ const char bb_busybox_exec_path[] ALIGN1 = CONFIG_BUSYBOX_EXEC_PATH;
const char bb_default_login_shell[] ALIGN1 = LIBBB_DEFAULT_LOGIN_SHELL;
/* util-linux manpage says /sbin:/bin:/usr/sbin:/usr/bin,
* but I want to save a few bytes here. Check libbb.h before changing! */
const char bb_PATH_root_path[] ALIGN1 =
"PATH=/sbin:/usr/sbin:/bin:/usr/bin" BB_ADDITIONAL_PATH;
const char bb_PATH_root_path[] ALIGN1 = BB_PATH_ROOT_PATH;
//const int const_int_1 = 1;