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Don't get tty group info multiple times in grantpt.

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This is a minor optimization.  The tty group mustn't change so a
successful call to getgrnam will always return the same information.
Cache it and reuse it.
This commit is contained in:
Ulrich Drepper 2009-11-24 17:50:27 -08:00
parent 80b3a4ea1c
commit 21f2c22320
2 changed files with 28 additions and 21 deletions
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3
ChangeLog
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@ -1,5 +1,8 @@
2009-11-24 Ulrich Drepper <drepper@redhat.com>
* sysdeps/unix/grantpt.c (grantpt): Only get tty group information
once.
* csu/elf-init.c (__libc_csu_irel): New function. Code to perform
irel relocations split out from...
(__libc_csu_init): ...here.

46
sysdeps/unix/grantpt.c
View File

@ -107,14 +107,6 @@ grantpt (int fd)
char _buf[512];
#endif
char *buf = _buf;
struct stat64 st;
char *grtmpbuf;
struct group grbuf;
size_t grbuflen = __sysconf (_SC_GETGR_R_SIZE_MAX);
struct group *p;
uid_t uid;
gid_t gid;
pid_t pid;
if (__builtin_expect (pts_name (fd, &buf, sizeof (_buf)), 0))
{
@ -126,34 +118,46 @@ grantpt (int fd)
return -1;
/* If the filedescriptor is no TTY, grantpt has to set errno
to EINVAL. */
to EINVAL. */
if (save_errno == ENOTTY)
__set_errno (EINVAL);
__set_errno (EINVAL);
else
__set_errno (save_errno);
return -1;
}
struct stat64 st;
if (__xstat64 (_STAT_VER, buf, &st) < 0)
goto cleanup;
/* Make sure that we own the device. */
uid = __getuid ();
uid_t uid = __getuid ();
if (st.st_uid != uid)
{
if (__chown (buf, uid, st.st_gid) < 0)
goto helper;
}
/* Get the group ID of the special `tty' group. */
if (grbuflen == (size_t) -1L)
/* `sysconf' does not support _SC_GETGR_R_SIZE_MAX.
Try a moderate value. */
grbuflen = 1024;
grtmpbuf = (char *) __alloca (grbuflen);
__getgrnam_r (TTY_GROUP, &grbuf, grtmpbuf, grbuflen, &p);
gid = p ? p->gr_gid : __getgid ();
static int tty_gid = -1;
if (__builtin_expect (tty_gid == -1, 0))
{
char *grtmpbuf;
struct group grbuf;
size_t grbuflen = __sysconf (_SC_GETGR_R_SIZE_MAX);
struct group *p;
/* Get the group ID of the special `tty' group. */
if (grbuflen == (size_t) -1L)
/* `sysconf' does not support _SC_GETGR_R_SIZE_MAX.
Try a moderate value. */
grbuflen = 1024;
grtmpbuf = (char *) __alloca (grbuflen);
__getgrnam_r (TTY_GROUP, &grbuf, grtmpbuf, grbuflen, &p);
if (p != NULL)
tty_gid = p->gr_gid;
}
gid_t gid = tty_gid == -1 ? __getgid () : tty_gid;
/* Make sure the group of the device is that special group. */
if (st.st_gid != gid)
@ -174,9 +178,9 @@ grantpt (int fd)
goto cleanup;
/* We have to use the helper program. */
helper:
helper:;
pid = __fork ();
pid_t pid = __fork ();
if (pid == -1)
goto cleanup;
else if (pid == 0)