Merge tag 'bsd-user-preen-2022q2-pull-request' of ssh://github.com/qemu-bsd-user/qemu-bsd-user into staging

bsd-user upstreaming: read, write and exit

This series of patches continues the effort to get system calls working
upstream. This series was cleaved off a prior series to give me time to rework
based on the feedback from the first time I posted these. read, write and exit
are implemented, along with a few helper functions and tracing.

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# gpg:                 aka "Warner Losh <imp@freebsd.org>" [unknown]
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# gpg:                 aka "Warner Losh <wlosh@bsdimp.com>" [unknown]
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# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2035 F894 B00A A3CF 7CCD  E1B7 6C1C D128 7DB0 1100

* tag 'bsd-user-preen-2022q2-pull-request' of ssh://github.com/qemu-bsd-user/qemu-bsd-user:
  bsd-user/freebsd/os-syscall.c: Implement exit
  bsd-user/bsd-file.h: Meat of the write system calls
  bsd-user/bsd-file.h: Add implementations for read, pread, readv and preadv
  bsd-user/freebsd/os-syscall.c: Tracing and error boilerplate
  bsd-user/freebsd/os-syscall.c: unlock_iovec
  bsd-user/freebsd/os-syscall.c: lock_iovec

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 163 insertions, 0 deletions

diff --git a/bsd-user/bsd-file.h b/bsd-user/bsd-file.h
index a6bff3b8c2..e9e2c85eb6 100644
--- a/bsd-user/bsd-file.h
+++ b/bsd-user/bsd-file.h
@@ -27,4 +27,167 @@ extern struct iovec *lock_iovec(int type, abi_ulong target_addr, int count,
 extern void unlock_iovec(struct iovec *vec, abi_ulong target_addr, int count,
         int copy);
 
+ssize_t safe_read(int fd, void *buf, size_t nbytes);
+ssize_t safe_pread(int fd, void *buf, size_t nbytes, off_t offset);
+ssize_t safe_readv(int fd, const struct iovec *iov, int iovcnt);
+ssize_t safe_preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset);
+
+ssize_t safe_write(int fd, void *buf, size_t nbytes);
+ssize_t safe_pwrite(int fd, void *buf, size_t nbytes, off_t offset);
+ssize_t safe_writev(int fd, const struct iovec *iov, int iovcnt);
+ssize_t safe_pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset);
+
+/* read(2) */
+static abi_long do_bsd_read(abi_long arg1, abi_long arg2, abi_long arg3)
+{
+    abi_long ret;
+    void *p;
+
+    p = lock_user(VERIFY_WRITE, arg2, arg3, 0);
+    if (p == NULL) {
+        return -TARGET_EFAULT;
+    }
+    ret = get_errno(safe_read(arg1, p, arg3));
+    unlock_user(p, arg2, ret);
+
+    return ret;
+}
+
+/* pread(2) */
+static abi_long do_bsd_pread(void *cpu_env, abi_long arg1,
+    abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5, abi_long arg6)
+{
+    abi_long ret;
+    void *p;
+
+    p = lock_user(VERIFY_WRITE, arg2, arg3, 0);
+    if (p == NULL) {
+        return -TARGET_EFAULT;
+    }
+    if (regpairs_aligned(cpu_env) != 0) {
+        arg4 = arg5;
+        arg5 = arg6;
+    }
+    ret = get_errno(safe_pread(arg1, p, arg3, target_arg64(arg4, arg5)));
+    unlock_user(p, arg2, ret);
+
+    return ret;
+}
+
+/* readv(2) */
+static abi_long do_bsd_readv(abi_long arg1, abi_long arg2, abi_long arg3)
+{
+    abi_long ret;
+    struct iovec *vec = lock_iovec(VERIFY_WRITE, arg2, arg3, 0);
+
+    if (vec != NULL) {
+        ret = get_errno(safe_readv(arg1, vec, arg3));
+        unlock_iovec(vec, arg2, arg3, 1);
+    } else {
+        ret = -host_to_target_errno(errno);
+    }
+
+    return ret;
+}
+
+/* preadv(2) */
+static abi_long do_bsd_preadv(void *cpu_env, abi_long arg1,
+    abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5, abi_long arg6)
+{
+    abi_long ret;
+    struct iovec *vec = lock_iovec(VERIFY_WRITE, arg2, arg3, 1);
+
+    if (vec != NULL) {
+        if (regpairs_aligned(cpu_env) != 0) {
+            arg4 = arg5;
+            arg5 = arg6;
+        }
+        ret = get_errno(safe_preadv(arg1, vec, arg3, target_arg64(arg4, arg5)));
+        unlock_iovec(vec, arg2, arg3, 0);
+    } else {
+        ret = -host_to_target_errno(errno);
+    }
+
+    return ret;
+}
+
+/* write(2) */
+static abi_long do_bsd_write(abi_long arg1, abi_long arg2, abi_long arg3)
+{
+    abi_long nbytes, ret;
+    void *p;
+
+    /* nbytes < 0 implies that it was larger than SIZE_MAX. */
+    nbytes = arg3;
+    if (nbytes < 0) {
+        return -TARGET_EINVAL;
+    }
+    p = lock_user(VERIFY_READ, arg2, nbytes, 1);
+    if (p == NULL) {
+        return -TARGET_EFAULT;
+    }
+    ret = get_errno(safe_write(arg1, p, arg3));
+    unlock_user(p, arg2, 0);
+
+    return ret;
+}
+
+/* pwrite(2) */
+static abi_long do_bsd_pwrite(void *cpu_env, abi_long arg1,
+    abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5, abi_long arg6)
+{
+    abi_long ret;
+    void *p;
+
+    p = lock_user(VERIFY_READ, arg2, arg3, 1);
+    if (p == NULL) {
+        return -TARGET_EFAULT;
+    }
+    if (regpairs_aligned(cpu_env) != 0) {
+        arg4 = arg5;
+        arg5 = arg6;
+    }
+    ret = get_errno(safe_pwrite(arg1, p, arg3, target_arg64(arg4, arg5)));
+    unlock_user(p, arg2, 0);
+
+    return ret;
+}
+
+/* writev(2) */
+static abi_long do_bsd_writev(abi_long arg1, abi_long arg2, abi_long arg3)
+{
+    abi_long ret;
+    struct iovec *vec = lock_iovec(VERIFY_READ, arg2, arg3, 1);
+
+    if (vec != NULL) {
+        ret = get_errno(safe_writev(arg1, vec, arg3));
+        unlock_iovec(vec, arg2, arg3, 0);
+    } else {
+        ret = -host_to_target_errno(errno);
+    }
+
+    return ret;
+}
+
+/* pwritev(2) */
+static abi_long do_bsd_pwritev(void *cpu_env, abi_long arg1,
+    abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5, abi_long arg6)
+{
+    abi_long ret;
+    struct iovec *vec = lock_iovec(VERIFY_READ, arg2, arg3, 1);
+
+    if (vec != NULL) {
+        if (regpairs_aligned(cpu_env) != 0) {
+            arg4 = arg5;
+            arg5 = arg6;
+        }
+        ret = get_errno(safe_pwritev(arg1, vec, arg3, target_arg64(arg4, arg5)));
+        unlock_iovec(vec, arg2, arg3, 0);
+    } else {
+        ret = -host_to_target_errno(errno);
+    }
+
+    return ret;
+}
+
 #endif /* BSD_FILE_H */