1 /* CC0 license (public domain) - see LICENSE file for details */
2 #include <ccan/pipecmd/pipecmd.h>
3 #include <ccan/noerr/noerr.h>
9 static char **gather_args(const char *arg0, va_list ap)
12 char **arr = calloc(sizeof(char *), n + 1);
16 arr[0] = (char *)arg0;
18 while ((arr[n++] = va_arg(ap, char *)) != NULL) {
19 arr = realloc(arr, sizeof(char *) * (n + 1));
26 pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, const char *cmd, va_list ap)
28 int tochild[2], fromchild[2], execfail[2];
33 if (pipe(tochild) != 0)
36 tochild[0] = open("/dev/null", O_RDONLY);
41 if (pipe(fromchild) != 0)
42 goto close_tochild_fail;
44 fromchild[1] = open("/dev/null", O_WRONLY);
46 goto close_tochild_fail;
48 if (pipe(execfail) != 0)
49 goto close_fromchild_fail;
51 if (fcntl(execfail[1], F_SETFD, fcntl(execfail[1], F_GETFD)
53 goto close_execfail_fail;
57 goto close_execfail_fail;
60 char **args = gather_args(cmd, ap);
68 // Child runs command.
72 if (tochild[0] != STDIN_FILENO) {
73 if (dup2(tochild[0], STDIN_FILENO) == -1)
74 goto child_errno_fail;
77 if (fromchild[1] != STDOUT_FILENO) {
78 if (dup2(fromchild[1], STDOUT_FILENO) == -1)
79 goto child_errno_fail;
86 write(execfail[1], &err, sizeof(err));
93 /* Child will close this without writing on successful exec. */
94 if (read(execfail[0], &err, sizeof(err)) == sizeof(err)) {
95 waitpid(childpid, NULL, 0);
100 *fd_tochild = tochild[1];
102 *fd_fromchild = fromchild[0];
106 close_noerr(execfail[0]);
107 close_noerr(execfail[1]);
108 close_fromchild_fail:
110 close_noerr(fromchild[0]);
111 close_noerr(fromchild[1]);
113 close_noerr(tochild[0]);
115 close_noerr(tochild[1]);
120 pid_t pipecmd(int *fd_fromchild, int *fd_tochild, const char *cmd, ...)
126 childpid = pipecmdv(fd_fromchild, fd_tochild, cmd, ap);