view auto/os/linux @ 9278:f53146df9a47

Fixed Valgrind complaints about uninitialized values. In ngx_http_source_charset(), name->data was left uninitialized, and only name->len was set. Since it is used in debug logging, this resulted in the following complaints from Valgrind on systems with musl libc: ==42== Conditional jump or move depends on uninitialised value(s) ==42== at 0x12BC66: memcpy (string.h:51) ==42== by 0x12BC66: ngx_sprintf_str (ngx_string.c:586) ==42== by 0x12C03C: ngx_vslprintf (ngx_string.c:255) ==42== by 0x127694: ngx_log_error_core (ngx_log.c:135) ==42== by 0x1B8795: ngx_http_charset_header_filter (ngx_http_charset_filter_module.c:252) Similarly, ngx_http_split_args() returned uninitialized arg->data, which was then copied to r->args, and also used in debug logging: ==42== Conditional jump or move depends on uninitialised value(s) ==42== at 0x12BC10: memcpy (string.h:50) ==42== by 0x12BC10: ngx_sprintf_str (ngx_string.c:586) ==42== by 0x12C03C: ngx_vslprintf (ngx_string.c:255) ==42== by 0x127694: ngx_log_error_core (ngx_log.c:135) ==42== by 0x184EFB: ngx_http_internal_redirect (ngx_http_core_module.c:2526) ==42== by 0x1D8CCC: ngx_http_try_files_handler (ngx_http_try_files_module.c:209) Fix is to initialize data to NULL. Note that, while memcpy(p, NULL, 0) is also formally undefined now, it is used in multiple places in the code, and expected to be allowed in C2y (see WG14 proposals N3177, N3261, "Allow zero length operations on null pointers"). Prodded by Valgrind.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 31 May 2024 04:38:09 +0300
parents 0af598651e33
children
line wrap: on
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# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


have=NGX_LINUX . auto/have_headers

CORE_INCS="$UNIX_INCS"
CORE_DEPS="$UNIX_DEPS $LINUX_DEPS"
CORE_SRCS="$UNIX_SRCS $LINUX_SRCS"

ngx_spacer='
'

cc_aux_flags="$CC_AUX_FLAGS"
CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64"


# Linux kernel version

version=$((`uname -r \
    | sed -n -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\)\.\([0-9][0-9]*\).*/ \
                                                 \1*256*256+\2*256+\3/p' \
             -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\).*/\1*256*256+\2*256/p'`))

version=${version:-0}


# posix_fadvise64() had been implemented in 2.5.60

if [ $version -lt 132412 ]; then
    have=NGX_HAVE_POSIX_FADVISE . auto/nohave
fi

# epoll, EPOLLET version

ngx_feature="epoll"
ngx_feature_name="NGX_HAVE_EPOLL"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/epoll.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int efd = 0;
                  struct epoll_event ee;
                  ee.events = EPOLLIN|EPOLLOUT|EPOLLET;
                  ee.data.ptr = NULL;
                  (void) ee;
                  efd = epoll_create(100);
                  if (efd == -1) return 1;"
. auto/feature

if [ $ngx_found = yes ]; then
    have=NGX_HAVE_CLEAR_EVENT . auto/have
    CORE_SRCS="$CORE_SRCS $EPOLL_SRCS"
    EVENT_MODULES="$EVENT_MODULES $EPOLL_MODULE"
    EVENT_FOUND=YES


    # EPOLLRDHUP appeared in Linux 2.6.17, glibc 2.8

    ngx_feature="EPOLLRDHUP"
    ngx_feature_name="NGX_HAVE_EPOLLRDHUP"
    ngx_feature_run=no
    ngx_feature_incs="#include <sys/epoll.h>"
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test="int efd = 0, fd = 0;
                      struct epoll_event ee;
                      ee.events = EPOLLIN|EPOLLRDHUP|EPOLLET;
                      ee.data.ptr = NULL;
                      epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ee)"
    . auto/feature


    # EPOLLEXCLUSIVE appeared in Linux 4.5, glibc 2.24

    ngx_feature="EPOLLEXCLUSIVE"
    ngx_feature_name="NGX_HAVE_EPOLLEXCLUSIVE"
    ngx_feature_run=no
    ngx_feature_incs="#include <sys/epoll.h>"
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test="int efd = 0, fd = 0;
                      struct epoll_event ee;
                      ee.events = EPOLLIN|EPOLLEXCLUSIVE;
                      ee.data.ptr = NULL;
                      epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ee)"
    . auto/feature


    # eventfd()

    ngx_feature="eventfd()"
    ngx_feature_name="NGX_HAVE_EVENTFD"
    ngx_feature_run=no
    ngx_feature_incs="#include <sys/eventfd.h>"
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test="(void) eventfd(0, 0)"
    . auto/feature

    if [ $ngx_found = yes ]; then
        have=NGX_HAVE_SYS_EVENTFD_H . auto/have
    fi


    if [ $ngx_found = no ]; then

        ngx_feature="eventfd() (SYS_eventfd)"
        ngx_feature_incs="#include <sys/syscall.h>"
        ngx_feature_test="(void) SYS_eventfd"
        . auto/feature
    fi
fi


# O_PATH and AT_EMPTY_PATH were introduced in 2.6.39, glibc 2.14

ngx_feature="O_PATH"
ngx_feature_name="NGX_HAVE_O_PATH"
ngx_feature_run=no
ngx_feature_incs="#include <sys/types.h>
                  #include <sys/stat.h>
                  #include <fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int fd; struct stat sb;
                  fd = openat(AT_FDCWD, \".\", O_PATH|O_DIRECTORY|O_NOFOLLOW);
                  if (fstatat(fd, \"\", &sb, AT_EMPTY_PATH) != 0) return 1"
. auto/feature


# sendfile()

CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE"
ngx_feature="sendfile()"
ngx_feature_name="NGX_HAVE_SENDFILE"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/sendfile.h>
                  #include <errno.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int s = 0, fd = 1;
                  ssize_t n; off_t off = 0;
                  n = sendfile(s, fd, &off, 1);
                  if (n == -1 && errno == ENOSYS) return 1"
. auto/feature

if [ $ngx_found = yes ]; then
    CORE_SRCS="$CORE_SRCS $LINUX_SENDFILE_SRCS"
fi


# sendfile64()

CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64"
ngx_feature="sendfile64()"
ngx_feature_name="NGX_HAVE_SENDFILE64"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/sendfile.h>
                  #include <errno.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int s = 0, fd = 1;
                  ssize_t n; off_t off = 0;
                  n = sendfile(s, fd, &off, 1);
                  if (n == -1 && errno == ENOSYS) return 1"
. auto/feature


ngx_include="sys/prctl.h"; . auto/include

# prctl(PR_SET_DUMPABLE)

ngx_feature="prctl(PR_SET_DUMPABLE)"
ngx_feature_name="NGX_HAVE_PR_SET_DUMPABLE"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/prctl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) == -1) return 1"
. auto/feature


# prctl(PR_SET_KEEPCAPS)

ngx_feature="prctl(PR_SET_KEEPCAPS)"
ngx_feature_name="NGX_HAVE_PR_SET_KEEPCAPS"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/prctl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) return 1"
. auto/feature


# capabilities

ngx_feature="capabilities"
ngx_feature_name="NGX_HAVE_CAPABILITIES"
ngx_feature_run=no
ngx_feature_incs="#include <linux/capability.h>
                  #include <sys/syscall.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct __user_cap_data_struct    data;
                  struct __user_cap_header_struct  header;

                  header.version = _LINUX_CAPABILITY_VERSION_1;
                  data.effective = CAP_TO_MASK(CAP_NET_RAW);
                  data.permitted = 0;

                  (void) header;
                  (void) data;
                  (void) SYS_capset"
. auto/feature


# crypt_r()

ngx_feature="crypt_r()"
ngx_feature_name="NGX_HAVE_GNU_CRYPT_R"
ngx_feature_run=no
ngx_feature_incs="#include <crypt.h>"
ngx_feature_path=
ngx_feature_libs=-lcrypt
ngx_feature_test="struct crypt_data  cd;
                  crypt_r(\"key\", \"salt\", &cd);"
. auto/feature


ngx_include="sys/vfs.h";     . auto/include


# BPF sockhash

ngx_feature="BPF sockhash"
ngx_feature_name="NGX_HAVE_BPF"
ngx_feature_run=no
ngx_feature_incs="#include <linux/bpf.h>
                  #include <sys/syscall.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="union bpf_attr attr = { 0 };

                  attr.map_flags = 0;
                  attr.map_type = BPF_MAP_TYPE_SOCKHASH;

                  syscall(__NR_bpf, 0, &attr, 0);"
. auto/feature

if [ $ngx_found = yes ]; then
    CORE_SRCS="$CORE_SRCS src/core/ngx_bpf.c"
    CORE_DEPS="$CORE_DEPS src/core/ngx_bpf.h"

    if [ $QUIC_BPF != NONE ]; then
        QUIC_BPF=YES
    fi
fi


ngx_feature="SO_COOKIE"
ngx_feature_name="NGX_HAVE_SO_COOKIE"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
                  $NGX_INCLUDE_INTTYPES_H"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="socklen_t optlen = sizeof(uint64_t);
                  uint64_t cookie;
                  getsockopt(0, SOL_SOCKET, SO_COOKIE, &cookie, &optlen)"
. auto/feature

if [ $ngx_found = yes ]; then
    SO_COOKIE_FOUND=YES
fi


# UDP segmentation offloading

ngx_feature="UDP_SEGMENT"
ngx_feature_name="NGX_HAVE_UDP_SEGMENT"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
                  #include <netinet/udp.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="socklen_t optlen = sizeof(int);
                  int val;
                  getsockopt(0, SOL_UDP, UDP_SEGMENT, &val, &optlen)"
. auto/feature


CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64"