[sheepdog] [PATCH v2] logger: allow sheep dump core file for non-root startup

[Liu Yuan]

From: Liu Yuan <tailai.ly at taobao.com>

v2:
 - Apply this to sheep binary too
-------------------------------------- >8

As a side effect, the coredump file will be located /path/to/store dir
instead of previous '/'. We also don't overlap core file when multiple sheeps
run on the same machine.

Signed-off-by: Liu Yuan <tailai.ly at taobao.com>
---
 lib/logger.c  |    8 ++++++--
 sheep/sheep.c |    5 +++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/logger.c b/lib/logger.c
index 5bce85c..04ba933 100644
--- a/lib/logger.c
+++ b/lib/logger.c
@@ -29,6 +29,7 @@
 #include <sys/wait.h>
 #include <sys/prctl.h>
 #include <pthread.h>
+#include <libgen.h>
 
 #include "logger.h"
 #include "util.h"
@@ -404,12 +405,15 @@ notrace int log_init(char *program_name, int size, int to_stdout, int level,
 {
 	off_t offset;
 	size_t log_size;
+	char log_dir[PATH_MAX];
 
 	log_level = level;
 
 	logdbg(stderr, "entering log_init\n");
 	log_name = program_name;
 	log_nowname = outfile;
+	strcpy(log_dir, outfile);
+	strcpy(log_dir, dirname(log_dir));
 
 	semkey = random();
 
@@ -465,8 +469,8 @@ notrace int log_init(char *program_name, int size, int to_stdout, int level,
 		dup2(fd, 1);
 		dup2(fd, 2);
 		setsid();
-		if (chdir("/") < 0) {
-			syslog(LOG_ERR, "failed to chdir to /: %m\n");
+		if (chdir(log_dir) < 0) {
+			syslog(LOG_ERR, "failed to chdir to %s: %m\n", log_dir);
 			exit(1);
 		}
 
diff --git a/sheep/sheep.c b/sheep/sheep.c
index 5a67289..491f49f 100644
--- a/sheep/sheep.c
+++ b/sheep/sheep.c
@@ -279,6 +279,11 @@ int main(int argc, char **argv)
 	if (ret)
 		exit(1);
 
+	if (chdir(dir) < 0) {
+		fprintf(stderr, "failed to chdir to %s: %m\n", dir);
+		exit(1);
+	}
+
 	vprintf(SDOG_NOTICE, "sheepdog daemon (version %s) started\n", PACKAGE_VERSION);
 
 	while (!sys_stat_shutdown() || sys->nr_outstanding_reqs != 0)
-- 
1.7.10.2