diff options
| -rw-r--r-- | lib/replace/libreplace.m4 | 7 | ||||
| -rw-r--r-- | lib/replace/test/incoherent_mmap.c | 83 | ||||
| -rw-r--r-- | lib/replace/wscript | 7 |
3 files changed, 97 insertions, 0 deletions
diff --git a/lib/replace/libreplace.m4 b/lib/replace/libreplace.m4 index ca0c6846ab..e14fadabf1 100644 --- a/lib/replace/libreplace.m4 +++ b/lib/replace/libreplace.m4 @@ -107,6 +107,13 @@ if test x"$libreplace_cv_HAVE_MREMAP" = x"yes"; then AC_DEFINE(HAVE_MREMAP,1,[Whether mremap works]) fi +AC_CACHE_CHECK([for incoherent mmap],libreplace_cv_HAVE_INCOHERENT_MMAP,[ +AC_TRY_RUN([#include "$libreplacedir/test/incoherent_mmap.c"], + libreplace_cv_HAVE_INCOHERENT_MMAP=yes,libreplace_cv_HAVE_INCOHERENT_MMAP=no,libreplace_cv_HAVE_INCOHERENT_MMAP=cross)]) +if test x"$libreplace_cv_HAVE_INCOHERENT_MMAP" = x"yes"; then + AC_DEFINE(HAVE_INCOHERENT_MMAP,1,[Whether mmap is incoherent against write]) +fi + AC_CHECK_HEADERS(sys/syslog.h syslog.h) AC_CHECK_HEADERS(sys/time.h time.h) diff --git a/lib/replace/test/incoherent_mmap.c b/lib/replace/test/incoherent_mmap.c new file mode 100644 index 0000000000..ee288fd806 --- /dev/null +++ b/lib/replace/test/incoherent_mmap.c @@ -0,0 +1,83 @@ +/* In OpenBSD, if you write to a file, another process doesn't see it + * in its mmap. Returns with exit status 0 if that is the case, 1 if + * it's coherent, and other if there's a problem. */ +#include <err.h> +#include <sys/mman.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> + +#define DATA "coherent.mmap" + +int main(int argc, char *argv[]) +{ + int tochild[2], toparent[2]; + int fd; + volatile unsigned char *map; + unsigned char *page; + const char *fname = argv[1]; + char c = 0; + + if (pipe(tochild) != 0 || pipe(toparent) != 0) + err(2, "Creating pipe"); + + if (!fname) + fname = DATA; + + fd = open(fname, O_RDWR|O_CREAT|O_TRUNC, 0600); + if (fd < 0) + err(2, "opening %s", fname); + unlink(fname); + + switch (fork()) { + case -1: + err(2, "Fork"); + case 0: + close(tochild[1]); + close(toparent[0]); + + /* Wait for parent to create file. */ + if (read(tochild[0], &c, 1) != 1) + err(2, "reading from parent"); + + /* Alter first byte. */ + pwrite(fd, &c, 1, 0); + + if (write(toparent[1], &c, 1) != 1) + err(2, "writing to parent"); + exit(0); + + default: + close(tochild[0]); + close(toparent[1]); + + /* Create a file and mmap it. */ + page = malloc(getpagesize()); + memset(page, 0x42, getpagesize()); + if (write(fd, page, getpagesize()) != getpagesize()) + err(2, "writing first page"); + map = mmap(NULL, getpagesize(), PROT_READ|PROT_WRITE, + MAP_SHARED, fd, 0); + if (map == MAP_FAILED) + err(2, "mapping file"); + + if (*map != 0x42) + errx(2, "first byte isn't 0x42!"); + + /* Tell child to alter file. */ + if (write(tochild[1], &c, 1) != 1) + err(2, "writing to child"); + + if (read(toparent[0], &c, 1) != 1) + err(2, "reading from child"); + + if (*map) + errx(0, "mmap incoherent: first byte isn't 0."); + + exit(1); + } +} diff --git a/lib/replace/wscript b/lib/replace/wscript index 36c2f0f3e1..63944c3800 100644 --- a/lib/replace/wscript +++ b/lib/replace/wscript @@ -299,6 +299,13 @@ def configure(conf): addmain=False, msg="Checking for C99 vsnprintf") + # OpenBSD (and I've heard HPUX) doesn't sync between mmap and write. + # FIXME: Anything other than a 0 or 1 exit code should abort configure! + conf.CHECK_CODE('#include "test/incoherent_mmap.c"', + addmain=False, add_headers=False, execute=True, + define='HAVE_INCOHERENT_MMAP', + msg="Checking for HAVE_INCOHERENT_MMAP") + conf.SAMBA_BUILD_ENV() conf.CHECK_CODE(''' |