We do this by defining DB_DUMP unconditionally and then testing the special exit code given by the shell if the command is not found (see http://www.tldp.org/LDP/abs/html/exitcodes.html). Packagers may either: (1) Provide db_dump as a build requirement, but make it a weak dependency at runtime, or: (2) Not provide db_dump at build time, but define DB_DUMP to its expected path when configuring, eg: DB_DUMP=/usr/bin/db_dump ./configure which will then be compiled into the library and used if available at runtime (or ignored as in case (1) if not available at runtime). --- lib/dbdump.c | 11 +++++++---- lib/inspect-apps.c | 8 -------- m4/guestfs-progs.m4 | 8 ++------ 3 files changed, 9 insertions(+), 18 deletions(-) diff --git a/lib/dbdump.c b/lib/dbdump.c index 7c17ce6b3..3ec11f2bd 100644 --- a/lib/dbdump.c +++ b/lib/dbdump.c @@ -31,8 +31,6 @@ #include "guestfs.h" #include "guestfs-internal.h" -#if defined(DB_DUMP) - static void read_db_dump_line (guestfs_h *g, void *datav, const char *line, size_t len); static unsigned char *convert_hex_to_binary (guestfs_h *g, const char *hex, size_t hexlen, size_t *binlen_rtn); @@ -75,6 +73,13 @@ guestfs_int_read_db_dump (guestfs_h *g, if (r == -1) return -1; + if (WIFEXITED (r) && WEXITSTATUS (r) == 127) { + /* Allow the command to be missing at runtime so that packagers can + * use weak dependencies. In this case it's not an error, we + * return an empty list. + */ + return 0; + } if (!WIFEXITED (r) || WEXITSTATUS (r) != 0) { guestfs_int_external_command_failed (g, r, DB_DUMP, NULL); return -1; @@ -225,5 +230,3 @@ convert_hex_to_binary (guestfs_h *g, const char *hex, size_t hexlen, *binlen_rtn = binlen; return bin; } - -#endif /* defined(DB_DUMP) */ diff --git a/lib/inspect-apps.c b/lib/inspect-apps.c index f0cf16b38..57428a3ba 100644 --- a/lib/inspect-apps.c +++ b/lib/inspect-apps.c @@ -45,9 +45,7 @@ #include "guestfs-internal-actions.h" #include "structs-cleanups.h" -#ifdef DB_DUMP static struct guestfs_application2_list *list_applications_rpm (guestfs_h *g, const char *root); -#endif static struct guestfs_application2_list *list_applications_deb (guestfs_h *g, const char *root); static struct guestfs_application2_list *list_applications_pacman (guestfs_h *g, const char *root); static struct guestfs_application2_list *list_applications_apk (guestfs_h *g, const char *root); @@ -121,11 +119,9 @@ guestfs_impl_inspect_list_applications2 (guestfs_h *g, const char *root) if (STREQ (type, "linux") || STREQ (type, "hurd")) { if (STREQ (package_format, "rpm")) { -#ifdef DB_DUMP ret = list_applications_rpm (g, root); if (ret == NULL) return NULL; -#endif } else if (STREQ (package_format, "deb")) { ret = list_applications_deb (g, root); @@ -163,8 +159,6 @@ guestfs_impl_inspect_list_applications2 (guestfs_h *g, const char *root) return ret; } -#ifdef DB_DUMP - /* This data comes from the Name database, and contains the application * names and the first 4 bytes of each link field. */ @@ -409,8 +403,6 @@ list_applications_rpm (guestfs_h *g, const char *root) return NULL; } -#endif /* defined DB_DUMP */ - static struct guestfs_application2_list * list_applications_deb (guestfs_h *g, const char *root) { diff --git a/m4/guestfs-progs.m4 b/m4/guestfs-progs.m4 index 757d50d88..a36b9ad2d 100644 --- a/m4/guestfs-progs.m4 +++ b/m4/guestfs-progs.m4 @@ -65,12 +65,8 @@ AM_CONDITIONAL([HAVE_PO4A], [test "x$PO4A" != "xno"]) dnl Check for db_dump, db_load (optional). GUESTFS_FIND_DB_TOOL([DB_DUMP], [dump]) GUESTFS_FIND_DB_TOOL([DB_LOAD], [load]) -if test "x$DB_DUMP" != "xno"; then - AC_DEFINE_UNQUOTED([DB_DUMP],["$DB_DUMP"],[Name of db_dump program.]) -fi -if test "x$DB_LOAD" != "xno"; then - AC_DEFINE_UNQUOTED([DB_LOAD],["$DB_LOAD"],[Name of db_load program.]) -fi +AC_DEFINE_UNQUOTED([DB_DUMP],["$DB_DUMP"],[Name of db_dump program.]) +AC_DEFINE_UNQUOTED([DB_LOAD],["$DB_LOAD"],[Name of db_load program.]) dnl Check for netpbm programs (optional). AC_PATH_PROGS([PBMTEXT],[pbmtext],[no]) -- 2.19.0.rc0