[PATCH v3] build system: fix parallel building issue
Michael Olbrich
m.olbrich at pengutronix.de
Thu Apr 12 08:36:54 UTC 2018
The files generated by the include/config/MARKER target are in the
dependency list for applets/applet_tables.
If applets/applet_tables is created first during applets_dir then it will
be created again later as part of $(busybox-dirs).
As a result include/applet_tables.h is created again. This time while other
build commands may need it.
Let applets_dir depend on include/config/MARKER to avoid this particular
race condition and create the header files atomically to ensure that the
compiler never sees incomplete files.
Signed-off-by: Michael Olbrich <m.olbrich at pengutronix.de>
---
Next try, this time with the correct dependency.
Michael
Makefile | 2 +-
applets/applet_tables.c | 16 ++++++++++++++--
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/Makefile b/Makefile
index 03a57adf3204..9d7a0a36c149 100644
--- a/Makefile
+++ b/Makefile
@@ -368,7 +368,7 @@ gen_build_files: $(wildcard $(srctree)/*/*.c) $(wildcard $(srctree)/*/*/*.c)
# we depend on scripts_basic, since scripts/basic/fixdep
# must be built before any other host prog
PHONY += applets_dir
-applets_dir: scripts_basic gen_build_files
+applets_dir: scripts_basic gen_build_files include/config/MARKER
$(Q)$(MAKE) $(build)=applets
applets/%: applets_dir ;
diff --git a/applets/applet_tables.c b/applets/applet_tables.c
index ef911a43b36d..e3d10c83f1b9 100644
--- a/applets/applet_tables.c
+++ b/applets/applet_tables.c
@@ -10,6 +10,7 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
+#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
@@ -61,6 +62,7 @@ static int str_isalnum_(const char *s)
int main(int argc, char **argv)
{
int i, j;
+ char tmp1[PATH_MAX], tmp2[PATH_MAX];
// In find_applet_by_name(), before linear search, narrow it down
// by looking at N "equidistant" names. With ~350 applets:
@@ -84,7 +86,8 @@ int main(int argc, char **argv)
if (!argv[1])
return 1;
- i = open(argv[1], O_WRONLY | O_TRUNC | O_CREAT, 0666);
+ snprintf(tmp1, PATH_MAX, "%s.%u.new", argv[1], (int) getpid());
+ i = open(tmp1, O_WRONLY | O_TRUNC | O_CREAT, 0666);
if (i < 0)
return 1;
dup2(i, 1);
@@ -209,12 +212,21 @@ int main(int argc, char **argv)
// fclose(fp);
// }
// if (strcmp(line_old, line_new) != 0) {
- fp = fopen(argv[2], "w");
+ snprintf(tmp2, PATH_MAX, "%s.%u.new", argv[2], (int) getpid());
+ fp = fopen(tmp2, "w");
if (!fp)
return 1;
fputs(line_new, fp);
+ if (fclose(fp))
+ return 1;
// }
}
+ if (fclose(stdout))
+ return 1;
+ if (rename(tmp1, argv[1]))
+ return 1;
+ if (rename(tmp2, argv[2]))
+ return 1;
return 0;
}
--
2.17.0
More information about the busybox
mailing list