Check whether realpath(3) supports the resolved_path == NULL feature, standardized in POSIX.1-2008.
This is tested by executing the realpath(3) with NULL as second argument and the program is expected to SIGSEGV in case the feature is not supported. If the feature is not supported the compatibility code calls realpath(3) with second argument pointing to buffer with MAX_PATH in size. With this more systems are supported; those that have POSIX.1-2008 -capable realpath(3) and those that have MAX_PATH defined and realpath(3) does not exceed that limit. --- I tested running configure and then make test; then make clean, edited Makefile.config POSIX_2008_REALPATH = 0 and make clean again. then tested sigsegv'ing with (memcpy(0, 0, 4)... configure | 32 ++++++++++++++++++++++++++++++-- notmuch-config.c | 21 ++++++++++++++++++++- 2 files changed, 50 insertions(+), 3 deletions(-) diff --git a/configure b/configure index 13b6062..8174219 100755 --- a/configure +++ b/configure @@ -454,6 +454,29 @@ echo $util_byte_order rm -f _byteorder _byteorder.c +printf "Checking for posix 2008 realpath()... " +# resolved_path == NULL is standardized in POSIX.1-2008 +cat > _posix_2008_realpath.c <<EOF +#define _BSD_SOURCE +#include <limits.h> +#include <stdlib.h> +#include <signal.h> +void exit1(int sig) { exit(1); } +int main () { + signal(SIGSEGV, exit1); + int main () { realpath (".", (char*)0); return 0; +} +EOF +${CC} ${CFLAGS} _posix_2008_realpath.c -o _posix_2008_realpath > /dev/null 2>&1 +if ./_posix_2008_realpath; then + echo Yes. + posix_2008_realpath=1 +else + echo No. + posix_2008_realpath=0 +fi +rm -f _posix_2008_realpath _posix_2008_realpath.c + if [ $errors -gt 0 ]; then cat <<EOF @@ -718,6 +741,9 @@ libdir = ${LIBDIR:=\$(prefix)/lib} # byte order within a 32 bit word. 1234 = little, 4321 = big, 0 = guess UTIL_BYTE_ORDER = ${util_byte_order} +# Whether realpath(3) supports resolved_path == NULL feature +POSIX_2008_REALPATH = ${posix_2008_realpath} + # Whether libdir is in a path configured into ldconfig LIBDIR_IN_LDCONFIG = ${libdir_in_ldconfig} @@ -824,7 +850,8 @@ CONFIGURE_CFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS) \\ -DSTD_GETPWUID=\$(STD_GETPWUID) \\ -DSTD_ASCTIME=\$(STD_ASCTIME) \\ -DHAVE_XAPIAN_COMPACT=\$(HAVE_XAPIAN_COMPACT) \\ - -DUTIL_BYTE_ORDER=\$(UTIL_BYTE_ORDER) + -DUTIL_BYTE_ORDER=\$(UTIL_BYTE_ORDER) \\ + -DPOSIX_2008_REALPATH=\$(POSIX_2008_REALPATH) CONFIGURE_CXXFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS) \\ \$(TALLOC_CFLAGS) -DHAVE_VALGRIND=\$(HAVE_VALGRIND) \\ @@ -834,7 +861,8 @@ CONFIGURE_CXXFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS) \\ -DSTD_GETPWUID=\$(STD_GETPWUID) \\ -DSTD_ASCTIME=\$(STD_ASCTIME) \\ -DHAVE_XAPIAN_COMPACT=\$(HAVE_XAPIAN_COMPACT) \\ - -DUTIL_BYTE_ORDER=\$(UTIL_BYTE_ORDER) + -DUTIL_BYTE_ORDER=\$(UTIL_BYTE_ORDER) \\ + -DPOSIX_2008_REALPATH=\$(POSIX_2008_REALPATH) CONFIGURE_LDFLAGS = \$(GMIME_LDFLAGS) \$(TALLOC_LDFLAGS) \$(XAPIAN_LDFLAGS) EOF diff --git a/notmuch-config.c b/notmuch-config.c index 8d28653..14d0e5c 100644 --- a/notmuch-config.c +++ b/notmuch-config.c @@ -454,10 +454,26 @@ notmuch_config_save (notmuch_config_t *config) } /* Try not to overwrite symlinks. */ +#if POSIX_2008_REALPATH filename = realpath (config->filename, NULL); +#else + /* compatibility with minor effort, not elegance, is the ruling factor + in these (two) else branches... */ + char resolved_path[PATH_MAX]; + filename = realpath (config->filename, resolved_path); +#endif if (! filename) { if (errno == ENOENT) { +#if POSIX_2008_REALPATH filename = strdup (config->filename); +#else + /* ... this is the other else... */ + resolved_path[sizeof resolved_path - 1] = '\0'; + strncpy(resolved_path, config->filename, sizeof resolved_path); + /* "faking" out of memory in case path too long -- close enough? */ + filename = resolved_path[sizeof resolved_path - 1]? + resolved_path: NULL; +#endif if (! filename) { fprintf (stderr, "Out of memory.\n"); g_free (data); @@ -480,12 +496,15 @@ notmuch_config_save (notmuch_config_t *config) filename, error->message); } g_error_free (error); +#if POSIX_2008_REALPATH free (filename); +#endif g_free (data); return 1; } - +#if POSIX_2008_REALPATH free (filename); +#endif g_free (data); return 0; } -- 1.8.5.3