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path: root/src/daemontools-extras/s6-setlock.c
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Diffstat (limited to 'src/daemontools-extras/s6-setlock.c')
-rw-r--r--src/daemontools-extras/s6-setlock.c87
1 files changed, 87 insertions, 0 deletions
diff --git a/src/daemontools-extras/s6-setlock.c b/src/daemontools-extras/s6-setlock.c
new file mode 100644
index 0000000..2fb6f12
--- /dev/null
+++ b/src/daemontools-extras/s6-setlock.c
@@ -0,0 +1,87 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/uint.h>
+#include <skalibs/tai.h>
+#include <skalibs/iopause.h>
+#include <skalibs/djbunix.h>
+#include <s6/config.h>
+
+#define USAGE "s6-setlock [ -r | -w ] [ -n | -N | -t timeout ] lockfile prog..."
+#define dieusage() strerr_dieusage(100, USAGE)
+
+typedef int lockfunc_t (int) ;
+typedef lockfunc_t *lockfunc_t_ref ;
+
+static lockfunc_t_ref f[2][2] = { { &lock_sh, &lock_shnb }, { &lock_ex, &lock_exnb } } ;
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+ unsigned int nb = 0, ex = 1 ;
+ unsigned int timeout = 0 ;
+ PROG = "s6-setlock" ;
+ for (;;)
+ {
+ register int opt = subgetopt(argc, argv, "nNrwt:") ;
+ if (opt == -1) break ;
+ switch (opt)
+ {
+ case 'n' : nb = 1 ; break ;
+ case 'N' : nb = 0 ; break ;
+ case 'r' : ex = 0 ; break ;
+ case 'w' : ex = 1 ; break ;
+ case 't' : if (!uint0_scan(subgetopt_here.arg, &timeout)) dieusage() ;
+ nb = 2 ; break ;
+ default : dieusage() ;
+ }
+ }
+ argc -= subgetopt_here.ind ; argv += subgetopt_here.ind ;
+ if (argc < 2) dieusage() ;
+
+ if (nb < 2)
+ {
+ int fd = open_create(argv[0]) ;
+ if (fd == -1) strerr_diefu2sys(111, "open_create ", argv[0]) ;
+ if ((*f[ex][nb])(fd) == -1) strerr_diefu2sys(1, "lock ", argv[0]) ;
+ }
+ else
+ {
+ char const *cargv[3] = { "s6lockd-helper", argv[0], 0 } ;
+ char const *cenvp[2] = { ex ? "S6LOCK_EX=1" : 0, 0 } ;
+ iopause_fd x = { .events = IOPAUSE_READ } ;
+ tain_t deadline ;
+ int p[2] ;
+ unsigned int pid ;
+ char c ;
+ if (!tain_now_g()) strerr_diefu1sys(111, "tain_now") ;
+ tain_from_millisecs(&deadline, timeout) ;
+ tain_add_g(&deadline, &deadline) ;
+ pid = child_spawn(S6_BINPREFIX "s6lockd-helper", cargv, cenvp, p, 2) ;
+ if (!pid) strerr_diefu2sys(111, "spawn ", S6_BINPREFIX "s6lockd-helper") ;
+ x.fd = p[0] ;
+ for (;;)
+ {
+ register int r = iopause_g(&x, 1, &deadline) ;
+ if (r < 0) strerr_diefu1sys(111, "iopause") ;
+ if (!r)
+ {
+ kill(pid, SIGTERM) ;
+ errno = ETIMEDOUT ;
+ strerr_diefu1sys(1, "acquire lock") ;
+ }
+ r = sanitize_read(fd_read(p[0], &c, 1)) ;
+ if (r < 0) strerr_diefu1sys(111, "read ack from helper") ;
+ if (r) break ;
+ }
+ if (c != '!') strerr_dief1x(111, "helper sent garbage ack") ;
+ fd_close(p[0]) ;
+ if (uncoe(p[1]) < 0) strerr_diefu1sys(111, "uncoe fd to helper") ;
+ }
+ pathexec_run(argv[1], argv+1, envp) ;
+ strerr_dieexec(111, argv[1]) ;
+}