From 05ae46ee7a70b158d58b2c8581451fed9c18da2a Mon Sep 17 00:00:00 2001 From: Érico Nogueira Date: Mon, 3 May 2021 22:51:52 -0300 Subject: linux: implement ttyname as a wrapper around ttyname_r. Big win in binary size and avoids duplicating the logic in multiple places. On x86_64, dropped from 1883206 to 1881790, a 1416 byte decrease. Also changed logic to track if ttyname_buf has been allocated by checking if it's NULL instead of tracking buflen as an additional variable. Reviewed-by: Adhemerval Zanella --- sysdeps/unix/sysv/linux/ttyname.c | 170 +++--------------------------------- sysdeps/unix/sysv/linux/ttyname_r.c | 2 +- 2 files changed, 13 insertions(+), 159 deletions(-) (limited to 'sysdeps') diff --git a/sysdeps/unix/sysv/linux/ttyname.c b/sysdeps/unix/sysv/linux/ttyname.c index d561ac12f2..034f197f99 100644 --- a/sysdeps/unix/sysv/linux/ttyname.c +++ b/sysdeps/unix/sysv/linux/ttyname.c @@ -17,188 +17,42 @@ #include #include -#include -#include -#include -#include #include -#include -#include #include -#include <_itoa.h> - #include "ttyname.h" -#if 0 -/* Is this used anywhere? It is not exported. */ -char *__ttyname; -#endif - -static char *getttyname (const char *dev, const struct stat64 *mytty, - int save, int *dostat); - -libc_freeres_ptr (static char *getttyname_name); +static char *ttyname_buf = NULL; -static char * -attribute_compat_text_section -getttyname (const char *dev, const struct stat64 *mytty, int save, int *dostat) +libc_freeres_fn (free_mem) { - static size_t namelen; - struct stat64 st; - DIR *dirstream; - struct dirent64 *d; - size_t devlen = strlen (dev) + 1; - - dirstream = __opendir (dev); - if (dirstream == NULL) - { - *dostat = -1; - return NULL; - } - - /* Prepare for the loop. If we already have a buffer copy the directory - name we look at into it. */ - if (devlen < namelen) - *((char *) __mempcpy (getttyname_name, dev, devlen - 1)) = '/'; - - while ((d = __readdir64 (dirstream)) != NULL) - if ((d->d_fileno == mytty->st_ino || *dostat) - && strcmp (d->d_name, "stdin") - && strcmp (d->d_name, "stdout") - && strcmp (d->d_name, "stderr")) - { - size_t dlen = _D_ALLOC_NAMLEN (d); - if (devlen + dlen > namelen) - { - free (getttyname_name); - namelen = 2 * (devlen + dlen); /* Big enough. */ - getttyname_name = malloc (namelen); - if (! getttyname_name) - { - *dostat = -1; - /* Perhaps it helps to free the directory stream buffer. */ - (void) __closedir (dirstream); - return NULL; - } - *((char *) __mempcpy (getttyname_name, dev, devlen - 1)) = '/'; - } - memcpy (&getttyname_name[devlen], d->d_name, dlen); - if (__stat64 (getttyname_name, &st) == 0 - && is_mytty (mytty, &st)) - { - (void) __closedir (dirstream); -#if 0 - __ttyname = getttyname_name; -#endif - __set_errno (save); - return getttyname_name; - } - } - - (void) __closedir (dirstream); - __set_errno (save); - return NULL; + free (ttyname_buf); } - -/* Static buffer in `ttyname'. */ -libc_freeres_ptr (static char *ttyname_buf); - - /* Return the pathname of the terminal FD is open on, or NULL on errors. The returned storage is good only until the next call to this function. */ char * ttyname (int fd) { - static size_t buflen; - char procname[30]; - struct stat64 st, st1; - int dostat = 0; - int doispty = 0; - char *name; - int save = errno; - struct termios term; - /* isatty check, tcgetattr is used because it sets the correct - errno (EBADF resp. ENOTTY) on error. */ + errno (EBADF resp. ENOTTY) on error. Fast error path to avoid the + allocation */ + struct termios term; if (__glibc_unlikely (__tcgetattr (fd, &term) < 0)) return NULL; - if (__fstat64 (fd, &st) < 0) - return NULL; - - /* We try using the /proc filesystem. */ - *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0'; - - if (buflen == 0) + if (ttyname_buf == NULL) { - buflen = 4095; - ttyname_buf = (char *) malloc (buflen + 1); + ttyname_buf = malloc (PATH_MAX); if (ttyname_buf == NULL) - { - buflen = 0; - return NULL; - } - } - - ssize_t len = __readlink (procname, ttyname_buf, buflen); - if (__glibc_likely (len != -1)) - { - if ((size_t) len >= buflen) return NULL; - -#define UNREACHABLE_LEN strlen ("(unreachable)") - if (len > UNREACHABLE_LEN - && memcmp (ttyname_buf, "(unreachable)", UNREACHABLE_LEN) == 0) - { - memmove (ttyname_buf, ttyname_buf + UNREACHABLE_LEN, - len - UNREACHABLE_LEN); - len -= UNREACHABLE_LEN; - } - - /* readlink need not terminate the string. */ - ttyname_buf[len] = '\0'; - - /* Verify readlink result, fall back on iterating through devices. */ - if (ttyname_buf[0] == '/' - && __stat64 (ttyname_buf, &st1) == 0 - && is_mytty (&st, &st1)) - return ttyname_buf; - - doispty = 1; } - if (__stat64 ("/dev/pts", &st1) == 0 && S_ISDIR (st1.st_mode)) + int result = __ttyname_r (fd, ttyname_buf, PATH_MAX); + if (result != 0) { - name = getttyname ("/dev/pts", &st, save, &dostat); - } - else - { - __set_errno (save); - name = NULL; - } - - if (!name && dostat != -1) - { - name = getttyname ("/dev", &st, save, &dostat); - } - - if (!name && dostat != -1) - { - dostat = 1; - name = getttyname ("/dev", &st, save, &dostat); - } - - if (!name && doispty && is_pty (&st)) - { - /* We failed to figure out the TTY's name, but we can at least - signal that we did verify that it really is a PTY slave. - This happens when we have inherited the file descriptor from - a different mount namespace. */ - __set_errno (ENODEV); + __set_errno (result); return NULL; } - - return name; + return ttyname_buf; } diff --git a/sysdeps/unix/sysv/linux/ttyname_r.c b/sysdeps/unix/sysv/linux/ttyname_r.c index fa1578fb64..899a851a83 100644 --- a/sysdeps/unix/sysv/linux/ttyname_r.c +++ b/sysdeps/unix/sysv/linux/ttyname_r.c @@ -194,5 +194,5 @@ __ttyname_r (int fd, char *buf, size_t buflen) return ret; } - +libc_hidden_def (__ttyname_r) weak_alias (__ttyname_r, ttyname_r) -- cgit 1.4.1