android: backport pty implementation from aosp/master

This is not (yet) in l-preview branch but on master
The only way to prevent duplicated includes was to
test the existence of a new constant added after
l-preview bionic source release.

Also use compatible hasmntopt() return type
(swapon/off compilation warnings)

Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>

Change-Id: I4ee6e7752eab84de4566ae86a90171b8241fcaea

4 files changed, 139 insertions, 23 deletions

diff --git a/Android.mk b/Android.mk
index d37f450..1240bb1 100644
--- a/Android.mk
+++ b/Android.mk
@@ -79,7 +79,8 @@ SUBMAKE := make -s -C $(BB_PATH) CC=$(CC)
 
 BUSYBOX_SRC_FILES = \
 	$(shell cat $(BB_PATH)/busybox-$(BUSYBOX_CONFIG).sources) \
-	libbb/android.c
+	android/libc/pty.c \
+	android/android.c
 
 ifeq ($(TARGET_ARCH),arm)
     BUSYBOX_SRC_FILES += \
@@ -155,7 +156,6 @@ LOCAL_CFLAGS += \
   -Dgetusershell=busybox_getusershell \
   -Dsetusershell=busybox_setusershell \
   -Dendusershell=busybox_endusershell \
-  -Dttyname_r=busybox_ttyname_r \
   -Dgetmntent=busybox_getmntent \
   -Dgetmntent_r=busybox_getmntent_r \
   -Dgenerate_uuid=busybox_generate_uuid
@@ -221,7 +221,6 @@ LOCAL_CFLAGS += \
   -Dgetusershell=busybox_getusershell \
   -Dsetusershell=busybox_setusershell \
   -Dendusershell=busybox_endusershell \
-  -Dttyname_r=busybox_ttyname_r \
   -Dgetmntent=busybox_getmntent \
   -Dgetmntent_r=busybox_getmntent_r \
   -Dgenerate_uuid=busybox_generate_uuid
diff --git a/libbb/android.c b/android/android.c
index f4b8df3..7d191c9 100644
--- a/libbb/android.c
+++ b/android/android.c
@@ -17,16 +17,6 @@ int clearenv()
 	return 0;
 }
 
-/* bionic/stubs.c:ttyname not implemented anyway */
-int ttyname_r(int fd, char *name, size_t namesize)
-{
-	char *t = ttyname(fd);
-	if (!t)
-		return -1;
-	strncpy(name, ttyname(fd), namesize);
-	return 0;
-}
-
 /* no /etc/shells anyway */
 char *getusershell() { return NULL; }
 void setusershell() {}
@@ -76,13 +66,13 @@ int addmntent(FILE *fp UNUSED_PARAM, const struct mntent *mnt UNUSED_PARAM)
 	return 1;
 }
 
-const char *hasmntopt(const struct mntent *mnt, const char *opt)
+char *hasmntopt(const struct mntent *mnt, const char *opt)
 {
-	const char *o = mnt->mnt_opts;
+	char *o = mnt->mnt_opts;
 	size_t l = strlen(opt);
 
-	while ((o = strstr(o, opt)) && 
-			((o > mnt->mnt_opts && o[-1] != ',') || 
+	while ((o = strstr(o, opt)) &&
+			((o > mnt->mnt_opts && o[-1] != ',') ||
 			 (o[l] != 0 && o[l] != ',' && o[l] != '=')));
 	return o;
 }
diff --git a/android/libc/pty.c b/android/libc/pty.c
new file mode 100644
index 0000000..2765221
--- a/dev/null
+++ b/android/libc/pty.c
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* #ifndef BIONIC_L (implementation was made after BIONIC_L (l-preview) */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <termios.h>
+#include <unistd.h>
+
+#include <fcntl.h>
+/* if this constant is not defined, we are
+   ttyname is not in bionic */
+#ifndef SPLICE_F_GIFT
+
+int posix_openpt(int flags) {
+  return open("/dev/ptmx", flags);
+}
+
+int getpt(void) {
+  return posix_openpt(O_RDWR|O_NOCTTY);
+}
+
+#ifndef __BIONIC__
+int grantpt(int) {
+  return 0;
+}
+#endif
+
+char* ptsname(int fd) {
+  static char buf[64];
+  return ptsname_r(fd, buf, sizeof(buf)) == 0 ? buf : NULL;
+}
+
+int ptsname_r(int fd, char* buf, size_t len) {
+  if (buf == NULL) {
+    errno = EINVAL;
+    return errno;
+  }
+
+  unsigned int pty_num;
+  if (ioctl(fd, TIOCGPTN, &pty_num) != 0) {
+    errno = ENOTTY;
+    return errno;
+  }
+
+  if (snprintf(buf, len, "/dev/pts/%u", pty_num) >= (int) len) {
+    errno = ERANGE;
+    return errno;
+  }
+
+  return 0;
+}
+
+int bb_ttyname_r(int fd, char* buf, size_t len) {
+  if (buf == NULL) {
+    errno = EINVAL;
+    return errno;
+  }
+
+  if (!isatty(fd)) {
+    return errno;
+  }
+
+  char path[64];
+  snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
+
+  ssize_t count = readlink(path, buf, len);
+  if (count == -1) {
+    return errno;
+  }
+  if ((size_t) (count) == len) {
+    errno = ERANGE;
+    return errno;
+  }
+  buf[count] = '\0';
+  return 0;
+}
+
+char* bb_ttyname(int fd) {
+  static char buf[64];
+  return bb_ttyname_r(fd, buf, sizeof(buf)) == 0 ? buf : NULL;
+}
+
+int unlockpt(int fd) {
+  int unlock = 0;
+  return ioctl(fd, TIOCSPTLCK, &unlock);
+}
+
+#endif
diff --git a/include/android.h b/include/android.h
index a96605a..845a99d 100644
--- a/include/android.h
+++ b/include/android.h
@@ -31,9 +31,6 @@ void endutent(void);
 /* defined in bionic/mktemp.c */
 char *mkdtemp(char *);
 
-/* defined in bionic/stubs.c */
-char *ttyname(int);
-
 /* SYSCALLS */
 int    stime(time_t *);
 int    swapon(const char *, int);
@@ -54,8 +51,20 @@ int    getsid(pid_t);
 /* local definition in libbb/xfuncs_printf.c */
 int fdprintf(int fd, const char *format, ...);
 
-/* local definitions in libbb/android.c */
-int ttyname_r(int, char *, size_t);
+/* local definitions in android/android.c */
+#include <fcntl.h>
+#ifndef SPLICE_F_GIFT
+/* if this constant is not defined, we are
+   ttyname is not in bionic */
+char* bb_ttyname(int);
+int   bb_ttyname_r(int, char *, size_t);
+#define ttyname(n)       bb_ttyname(n)
+#define ttyname_r(n,s,z) bb_ttyname_r(n,s,z)
+#else
+/* should be available in android M ? */
+extern char* ttyname(int);
+extern int   ttyname_r(int, char *, size_t);
+#endif
 
 char *getusershell(void);
 void setusershell(void);
@@ -65,7 +74,7 @@ struct mntent;
 struct __sFILE;
 int addmntent(struct __sFILE *, const struct mntent *);
 struct mntent *getmntent_r(struct __sFILE *fp, struct mntent *mnt, char *buf, int buflen);
-const char *hasmntopt(const struct mntent *, const char *);
+char *hasmntopt(const struct mntent *, const char *);
 
 #define MNTOPT_NOAUTO "noauto"