From 19c1fd84d1fd75e9bfd55feb670fda87a2e02086 Mon Sep 17 00:00:00 2001
From: Samo Penic <samo.penic@gmail.com>
Date: Fri, 08 Feb 2019 08:32:29 +0000
Subject: [PATCH] Merge branch 'master' of ssh://git.penic.eu:29418/trisurf-ng
---
src/general.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 106 insertions(+), 0 deletions(-)
diff --git a/src/general.c b/src/general.c
index 1ada40d..6b8a99c 100644
--- a/src/general.c
+++ b/src/general.c
@@ -8,6 +8,10 @@
#include <unistd.h>
#include <time.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
ts_uint ts_fprintf(FILE *fd, char *fmt, ...){
if(quiet) return TS_SUCCESS;
@@ -33,3 +37,105 @@
}
+/* Open/create the file named in 'pidFile', lock it, optionally set the
+ close-on-exec flag for the file descriptor, write our PID into the file,
+ and (in case the caller is interested) return the file descriptor
+ referring to the locked file. The caller is responsible for deleting
+ 'pidFile' file (just) before process termination. 'progName' should be the
+ name of the calling program (i.e., argv[0] or similar), and is used only for
+ diagnostic messages. If we can't open 'pidFile', or we encounter some other
+ error, then we print an appropriate diagnostic and terminate. */
+
+/*
+ This is filelock/create_pid_file.c (Listing 55-4, page 1143), an example program file from the book, The Linux Programming Interface.
+
+The source code file is copyright 2010, Michael Kerrisk, and is licensed under the GNU Lesser General Public License, version 3.
+*/
+
+#define BUF_SIZE 100
+int createPidFile(const char *progName, const char *pidFile, int flags)
+{
+ int fd;
+ char buf[BUF_SIZE];
+
+ fd = open(pidFile, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+ if (fd == -1){
+ ts_fprintf(stderr,"Could not open PID file %s", pidFile);
+ fatal("Cannot continue (1)",1);
+}
+ if (flags & CPF_CLOEXEC) {
+
+ /* Set the close-on-exec file descriptor flag */
+
+ /* Instead of the following steps, we could (on Linux) have opened the
+ file with O_CLOEXEC flag. However, not all systems support open()
+ O_CLOEXEC (which was standardized only in SUSv4), so instead we use
+ fcntl() to set the close-on-exec flag after opening the file */
+
+ flags = fcntl(fd, F_GETFD); /* Fetch flags */
+ if (flags == -1){
+ ts_fprintf(stderr,"Could not get flags for PID file %s", pidFile);
+ fatal("Cannot continue (2)",1);
+}
+ flags |= FD_CLOEXEC; /* Turn on FD_CLOEXEC */
+
+ if (fcntl(fd, F_SETFD, flags) == -1) /* Update flags */
+ ts_fprintf(stderr,"Could not set flags for PID file %s", pidFile);
+ fatal("Cannot continue (3)",1);
+
+ }
+
+ if (lockRegion(fd, F_WRLCK, SEEK_SET, 0, 0) == -1) {
+ if (errno == EAGAIN || errno == EACCES){
+ ts_fprintf(stderr,"PID file '%s' is locked; probably "
+ "'%s' is already running", pidFile, progName);
+ fatal("Cannot continue (4)",1);
+}
+ else{
+ ts_fprintf(stderr,"Unable to lock PID file '%s'", pidFile);
+ fatal("Cannot continue (5)",1);
+}
+ }
+
+ if (ftruncate(fd, 0) == -1){
+ ts_fprintf(stderr,"Could not truncate PID file '%s'", pidFile);
+ fatal("Cannot continue (6)",1);
+}
+
+ snprintf(buf, BUF_SIZE, "%ld\n", (long) getpid());
+ if (write(fd, buf, strlen(buf)) != strlen(buf)){
+
+ ts_fprintf(stderr,"Writing to PID file '%s'", pidFile);
+ fatal("Cannot continue (7)",1);
+}
+ return fd;
+}
+
+
+
+/* Lock a file region (private; public interfaces below) */
+
+static int
+lockReg(int fd, int cmd, int type, int whence, int start, off_t len)
+{
+ struct flock fl;
+
+ fl.l_type = type;
+ fl.l_whence = whence;
+ fl.l_start = start;
+ fl.l_len = len;
+
+ return fcntl(fd, cmd, &fl);
+}
+
+
+int /* Lock a file region using nonblocking F_SETLK */
+lockRegion(int fd, int type, int whence, int start, int len)
+{
+ return lockReg(fd, F_SETLK, type, whence, start, len);
+}
+
+
+char *libVersion(){
+ return TS_VERSION;
+}
--
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