Re: [PATCH 1/7] Add termios2 support to linux-user

Heinrich Schuchardt Thu, 04 Dec 2025 04:49:48 -0800

On 10/31/25 14:23, Luca Bonissi wrote:

From 6ddab7d3ba1035b5e2a6016bde4776436267c18b Mon Sep 17 00:00:00 2001

From: Luca Bonissi <[email protected]>
Date: Fri, 31 Oct 2025 13:29:19 +0100
Subject: [PATCH 1/7] Add termios2 support to linux-user


Signed-off-by: Luca Bonissi <[email protected]>

This patch fixes the detection of the tty console in foreignarchitecture Docker containers when the host is using glibc 2.42 as onUbuntu 25.10 and 26.04.


I tested with an x86_64 host and foreign architectures aarch64 and riscv64.

@Luca:

Patches should provide a commit message explaining why the change is needed.

When respinning a patch it is preferable to mark it with a versionnumber (e.g. '[PATCH v2 1/7]) and to provide a change history under a'---' line.

Maybe you could resend the series with a proper commit message and markit as v3.


    git format-patch --cover-letter --subject-prefix='PATCH v3'

Please, use git send-email so that the patches of the series and thecover-letter arrive as related mails. git send-email sets theIn-Reply-To header for this purpose.


Tested-by: Heinrich Schuchardt <[email protected]>

---
  linux-user/ioctls.h         |  6 +++
  linux-user/strace.c         | 69 ++++++++++++++++++++++++++++++
  linux-user/syscall.c        | 84 +++++++++++++++++++++++++++++++++++++
  linux-user/syscall_types.h  |  3 ++
  linux-user/user-internals.h |  3 ++
  5 files changed, 165 insertions(+)

diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
index 2f62fd2cb9..6ecfe6306e 100644
--- a/linux-user/ioctls.h
+++ b/linux-user/ioctls.h
@@ -1,5 +1,11 @@
       /* emulated ioctl list */

+#ifdef TARGET_TCGETS2

+     IOCTL(TCGETS2, IOC_R, MK_PTR(MK_STRUCT(STRUCT_termios2)))
+     IOCTL(TCSETS2, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios2)))
+     IOCTL(TCSETSW2, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios2)))
+     IOCTL(TCSETSF2, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios2)))
+#endif
       IOCTL(TCGETS, IOC_R, MK_PTR(MK_STRUCT(STRUCT_termios)))
       IOCTL(TCSETS, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios)))
       IOCTL(TCSETSF, IOC_W, MK_PTR(MK_STRUCT(STRUCT_termios)))
diff --git a/linux-user/strace.c b/linux-user/strace.c
index 758c5d32b6..7afb94544f 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -1935,6 +1935,75 @@ print_termios(void *arg)
      qemu_log("}");
  }

+#ifdef TARGET_TCGETS2

+void
+print_termios2(void *arg)
+{
+    const struct target_termios2 *target = arg;
+
+    target_tcflag_t iflags = tswap32(target->c_iflag);
+    target_tcflag_t oflags = tswap32(target->c_oflag);
+    target_tcflag_t cflags = tswap32(target->c_cflag);
+    target_tcflag_t lflags = tswap32(target->c_lflag);
+
+    qemu_log("{");
+
+    qemu_log("c_iflag = ");
+    print_flags(termios_iflags, iflags, 0);
+
+    qemu_log("c_oflag = ");
+    target_tcflag_t oflags_clean =  oflags & ~(TARGET_NLDLY | TARGET_CRDLY |
+                                               TARGET_TABDLY | TARGET_BSDLY |
+                                               TARGET_VTDLY | TARGET_FFDLY);
+    print_flags(termios_oflags, oflags_clean, 0);
+    if (oflags & TARGET_NLDLY) {
+        print_enums(termios_oflags_NLDLY, oflags & TARGET_NLDLY, 0);
+    }
+    if (oflags & TARGET_CRDLY) {
+        print_enums(termios_oflags_CRDLY, oflags & TARGET_CRDLY, 0);
+    }
+    if (oflags & TARGET_TABDLY) {
+        print_enums(termios_oflags_TABDLY, oflags & TARGET_TABDLY, 0);
+    }
+    if (oflags & TARGET_BSDLY) {
+        print_enums(termios_oflags_BSDLY, oflags & TARGET_BSDLY, 0);
+    }
+    if (oflags & TARGET_VTDLY) {
+        print_enums(termios_oflags_VTDLY, oflags & TARGET_VTDLY, 0);
+    }
+    if (oflags & TARGET_FFDLY) {
+        print_enums(termios_oflags_FFDLY, oflags & TARGET_FFDLY, 0);
+    }
+
+    qemu_log("c_cflag = ");
+    if (cflags & TARGET_CBAUD) {
+        print_enums(termios_cflags_CBAUD, cflags & TARGET_CBAUD, 0);
+    }
+    if (cflags & TARGET_CSIZE) {
+        print_enums(termios_cflags_CSIZE, cflags & TARGET_CSIZE, 0);
+    }
+    target_tcflag_t cflags_clean = cflags & ~(TARGET_CBAUD | TARGET_CSIZE);
+    print_flags(termios_cflags, cflags_clean, 0);
+
+    qemu_log("c_lflag = ");
+    print_flags(termios_lflags, lflags, 0);
+
+    qemu_log("c_ispeed = ");
+    print_raw_param("%u", tswap32(target->c_ispeed), 0);
+
+    qemu_log("c_ospeed = ");
+    print_raw_param("%u", tswap32(target->c_ospeed), 0);
+
+    qemu_log("c_cc = ");
+    qemu_log("\"%s\",", target->c_cc);
+
+    qemu_log("c_line = ");
+    print_raw_param("\'%c\'", target->c_line, 1);
+
+    qemu_log("}");
+}
+#endif
+
  #undef UNUSED

#ifdef TARGET_NR_accept

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 8546f48a05..920bf23406 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -86,6 +86,7 @@
  #endif

#define termios host_termios

+#define termios2 host_termios2
  #define winsize host_winsize
  #define termio host_termio
  #define sgttyb host_sgttyb /* same as target */
@@ -5885,6 +5886,89 @@ static const StructEntry struct_termios_def = {
      .print = print_termios,
  };

+#ifdef TARGET_TCGETS2

+static void target_to_host_termios2 (void *dst, const void *src)
+{
+    struct host_termios2 *host = dst;
+    const struct target_termios2 *target = src;
+
+    host->c_iflag =
+        target_to_host_bitmask(tswap32(target->c_iflag), iflag_tbl);
+    host->c_oflag =
+        target_to_host_bitmask(tswap32(target->c_oflag), oflag_tbl);
+    host->c_cflag =
+        target_to_host_bitmask(tswap32(target->c_cflag), cflag_tbl);
+    host->c_lflag =
+        target_to_host_bitmask(tswap32(target->c_lflag), lflag_tbl);
+    host->c_line = target->c_line;
+    host->c_ispeed = tswap32(target->c_ispeed);
+    host->c_ospeed = tswap32(target->c_ospeed);
+
+    memset(host->c_cc, 0, sizeof(host->c_cc));
+    host->c_cc[VINTR] = target->c_cc[TARGET_VINTR];
+    host->c_cc[VQUIT] = target->c_cc[TARGET_VQUIT];
+    host->c_cc[VERASE] = target->c_cc[TARGET_VERASE];
+    host->c_cc[VKILL] = target->c_cc[TARGET_VKILL];
+    host->c_cc[VEOF] = target->c_cc[TARGET_VEOF];
+    host->c_cc[VTIME] = target->c_cc[TARGET_VTIME];
+    host->c_cc[VMIN] = target->c_cc[TARGET_VMIN];
+    host->c_cc[VSWTC] = target->c_cc[TARGET_VSWTC];
+    host->c_cc[VSTART] = target->c_cc[TARGET_VSTART];
+    host->c_cc[VSTOP] = target->c_cc[TARGET_VSTOP];
+    host->c_cc[VSUSP] = target->c_cc[TARGET_VSUSP];
+    host->c_cc[VEOL] = target->c_cc[TARGET_VEOL];
+    host->c_cc[VREPRINT] = target->c_cc[TARGET_VREPRINT];
+    host->c_cc[VDISCARD] = target->c_cc[TARGET_VDISCARD];
+    host->c_cc[VWERASE] = target->c_cc[TARGET_VWERASE];
+    host->c_cc[VLNEXT] = target->c_cc[TARGET_VLNEXT];
+    host->c_cc[VEOL2] = target->c_cc[TARGET_VEOL2];
+}
+
+static void host_to_target_termios2 (void *dst, const void *src)
+{
+    struct target_termios2 *target = dst;
+    const struct host_termios2 *host = src;
+
+    target->c_iflag =
+        tswap32(host_to_target_bitmask(host->c_iflag, iflag_tbl));
+    target->c_oflag =
+        tswap32(host_to_target_bitmask(host->c_oflag, oflag_tbl));
+    target->c_cflag =
+        tswap32(host_to_target_bitmask(host->c_cflag, cflag_tbl));
+    target->c_lflag =
+        tswap32(host_to_target_bitmask(host->c_lflag, lflag_tbl));
+    target->c_line = host->c_line;
+    target->c_ispeed = tswap32(host->c_ispeed);
+    target->c_ospeed = tswap32(host->c_ospeed);
+
+    memset(target->c_cc, 0, sizeof(target->c_cc));
+    target->c_cc[TARGET_VINTR] = host->c_cc[VINTR];
+    target->c_cc[TARGET_VQUIT] = host->c_cc[VQUIT];
+    target->c_cc[TARGET_VERASE] = host->c_cc[VERASE];
+    target->c_cc[TARGET_VKILL] = host->c_cc[VKILL];
+    target->c_cc[TARGET_VEOF] = host->c_cc[VEOF];
+    target->c_cc[TARGET_VTIME] = host->c_cc[VTIME];
+    target->c_cc[TARGET_VMIN] = host->c_cc[VMIN];
+    target->c_cc[TARGET_VSWTC] = host->c_cc[VSWTC];
+    target->c_cc[TARGET_VSTART] = host->c_cc[VSTART];
+    target->c_cc[TARGET_VSTOP] = host->c_cc[VSTOP];
+    target->c_cc[TARGET_VSUSP] = host->c_cc[VSUSP];
+    target->c_cc[TARGET_VEOL] = host->c_cc[VEOL];
+    target->c_cc[TARGET_VREPRINT] = host->c_cc[VREPRINT];
+    target->c_cc[TARGET_VDISCARD] = host->c_cc[VDISCARD];
+    target->c_cc[TARGET_VWERASE] = host->c_cc[VWERASE];
+    target->c_cc[TARGET_VLNEXT] = host->c_cc[VLNEXT];
+    target->c_cc[TARGET_VEOL2] = host->c_cc[VEOL2];
+}
+
+static const StructEntry struct_termios2_def = {
+    .convert = { host_to_target_termios2, target_to_host_termios2 },
+    .size = { sizeof(struct target_termios2), sizeof(struct host_termios2) },
+    .align = { __alignof__(struct target_termios2), __alignof__(struct 
host_termios2) },
+    .print = print_termios2,
+};
+#endif
+
  /* If the host does not provide these bits, they may be safely discarded. */
  #ifndef MAP_SYNC
  #define MAP_SYNC 0
diff --git a/linux-user/syscall_types.h b/linux-user/syscall_types.h
index 6dd7a80ce5..ac45705acf 100644
--- a/linux-user/syscall_types.h
+++ b/linux-user/syscall_types.h
@@ -1,4 +1,7 @@
  STRUCT_SPECIAL(termios)
+#ifdef TARGET_TCGETS2
+STRUCT_SPECIAL(termios2)
+#endif

STRUCT(winsize,

         TYPE_SHORT, TYPE_SHORT, TYPE_SHORT, TYPE_SHORT)
diff --git a/linux-user/user-internals.h b/linux-user/user-internals.h
index 7099349ec8..067c02bb93 100644
--- a/linux-user/user-internals.h
+++ b/linux-user/user-internals.h
@@ -129,6 +129,9 @@ static inline uint64_t target_offset64(uint64_t word0, 
uint64_t word1)
  #endif /* TARGET_ABI_BITS != 32 */

void print_termios(void *arg);

+#ifdef TARGET_TCGETS2
+void print_termios2(void *arg);
+#endif

/* ARM EABI and MIPS expect 64bit types aligned even on pairs or registers */

  #ifdef TARGET_ARM

Re: [PATCH 1/7] Add termios2 support to linux-user

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