Various common utility sources

[nethome.git] / src / flock.c

diff --git a/src/flock.c b/src/flock.c
new file mode 100644 (file)
index 0000000..e256676
--- /dev/null
+++ b/src/flock.c
@@ -0,0 +1,89 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <limits.h>
+#include <getopt.h>
+#include <sys/file.h>
+
+#define failf(name) do { fprintf(stderr,"%s: ",pname); perror(name"()"); exit(EXIT_FAILURE); } while (0)
+const char version[]="This is FLock, version 1.0\n";
+
+int verbose;
+
+char *pname;
+
+static __NORETURN void usage(void)
+{
+       fprintf(stderr,"\
+%s\
+This command acts as an interface to flock(2):\n\
+\n\
+Usage: flock [{-s|--shared}|{-x|--exclusive}] [-n|--nonblock]\n\
+             [-v|--verbose] [-h|--help] [-V|--version]\n\
+             <lockname> <command>\n\
+\n\
+  -s, --shared\tCreate shared lock (LOCK_SH) - DEFAULT\n\
+  -x, --exclusive\tCreate exclusive lock (LOCK_EX)\n\
+  -n, --nonblock\tFail immediately if req. lock is busy\n\
+  -v, --verbose\tDisplay progress during locking\n\
+  -h, --help\tPrint a summary of the options\n\
+  -V, --version\tPrint the version number\n\
+",version);
+       exit(EXIT_FAILURE);
+}
+
+const struct option longopts[]={
+{"shared"   ,0,0,'s'},
+{"exclusive",0,0,'x'},
+{"nonblock" ,0,0,'n'},
+{"verbose"  ,0,0,'v'},
+{"help"     ,0,0,'h'},
+{"version"  ,0,0,'V'}};
+
+int main(int argc,char **argv)
+{
+char *fn,*cmd;
+int locktype=LOCK_SH,nonblock=0,fd,optc;
+
+       pname=*argv;
+       while ((optc=getopt_long(argc,argv,"sxnvhV",longopts,NULL))!=EOF) switch (optc) {
+               case 's':
+                       locktype=LOCK_SH;
+                       break;
+               case 'x':
+                       locktype=LOCK_EX;
+                       break;
+               case 'n':
+                       nonblock=LOCK_NB;
+                       break;
+               case 'v':
+                       verbose=1;
+                       break;
+               case 'V':
+                       fprintf(stderr,version);
+                       exit(EXIT_FAILURE);
+               default: /* also 'h' */
+                       usage();
+                       break;
+               }
+       if (optind+2!=argc) {
+               fprintf(stderr,"%s: Incorrect number of parameters (command needs quoting?)!\n",pname);
+               exit(EXIT_FAILURE);
+               }
+       fn=argv[optind];
+       cmd=argv[optind+1];
+       if (verbose) { fprintf(stderr,"%s: Opening \"%s\"...",pname,fn); fflush(stderr); }
+       if ((fd=open(fn,O_RDONLY|(nonblock?O_NONBLOCK:0)))==-1) failf("open");
+       if (verbose) { fprintf(stderr,"done\n%s: Locking \"%s\"...",pname,fn); fflush(stderr); }
+       if (flock(fd,locktype|nonblock)) failf("flock");
+       if (verbose) { fprintf(stderr,"done\n%s: Running \"%s\"...",pname,cmd); fflush(stderr); }
+       if (system(cmd)==-1) failf("system");
+       if (verbose) { fprintf(stderr,"done\n%s: Finishing - removing lock.\n",pname); }
+       return(EXIT_SUCCESS);
+}