X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fpipecmd%2Fpipecmd.c;h=c2b514df5e97189230dbc282f3b673293a77028c;hp=352677fac1c216240eb38252216f72584793221c;hb=d3d2242ba8d975f8d7ddaa0348953dfd6f45ffce;hpb=66de67ea48009a086f940288eacf9928515f3aec

diff --git a/ccan/pipecmd/pipecmd.c b/ccan/pipecmd/pipecmd.c
index 352677fa..c2b514df 100644
--- a/ccan/pipecmd/pipecmd.c
+++ b/ccan/pipecmd/pipecmd.c
@@ -6,6 +6,8 @@
 #include <unistd.h>
 #include <fcntl.h>
 
+int pipecmd_preserve;
+
 static char **gather_args(const char *arg0, va_list ap)
 {
 	size_t n = 1;
@@ -16,21 +18,43 @@ static char **gather_args(const char *arg0, va_list ap)
 	arr[0] = (char *)arg0;
 
 	while ((arr[n++] = va_arg(ap, char *)) != NULL) {
-		arr = realloc(arr, sizeof(char *) * (n + 1));
-		if (!arr)
+		char **narr = realloc(arr, sizeof(char *) * (n + 1));
+		if (!narr) {
+			free(arr);
 			return NULL;
+		}
+		arr = narr;
 	}
 	return arr;
 }
 
-pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, const char *cmd, va_list ap)
+pid_t pipecmdv(int *fd_tochild, int *fd_fromchild, int *fd_errfromchild,
+	       const char *cmd, va_list ap)
+{
+	char **arr = gather_args(cmd, ap);
+	pid_t ret;
+
+	if (!arr) {
+		errno = ENOMEM;
+		return -1;
+	}
+	ret = pipecmdarr(fd_tochild, fd_fromchild, fd_errfromchild, arr);
+	free_noerr(arr);
+	return ret;
+}
+
+pid_t pipecmdarr(int *fd_tochild, int *fd_fromchild, int *fd_errfromchild,
+		 char *const *arr)
 {
-	int tochild[2], fromchild[2], execfail[2];
+	int tochild[2], fromchild[2], errfromchild[2], execfail[2];
 	pid_t childpid;
 	int err;
 
 	if (fd_tochild) {
-		if (pipe(tochild) != 0)
+		if (fd_tochild == &pipecmd_preserve) {
+			tochild[0] = STDIN_FILENO;
+			fd_tochild = NULL;
+		} else if (pipe(tochild) != 0)
 			goto fail;
 	} else {
 		tochild[0] = open("/dev/null", O_RDONLY);
@@ -38,15 +62,35 @@ pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, const char *cmd, va_list ap)
 			goto fail;
 	}
 	if (fd_fromchild) {
-		if (pipe(fromchild) != 0)
+		if (fd_fromchild == &pipecmd_preserve) {
+			fromchild[1] = STDOUT_FILENO;
+			fd_fromchild = NULL;
+		} else if (pipe(fromchild) != 0)
 			goto close_tochild_fail;
 	} else {
 		fromchild[1] = open("/dev/null", O_WRONLY);
 		if (fromchild[1] < 0)
 			goto close_tochild_fail;
 	}
+	if (fd_errfromchild) {
+		if (fd_errfromchild == &pipecmd_preserve) {
+			errfromchild[1] = STDERR_FILENO;
+			fd_errfromchild = NULL;
+		} else if (fd_errfromchild == fd_fromchild) {
+			errfromchild[0] = fromchild[0];
+			errfromchild[1] = fromchild[1];
+		} else {
+			if (pipe(errfromchild) != 0)
+				goto close_fromchild_fail;
+		}
+	} else {
+		errfromchild[1] = open("/dev/null", O_WRONLY);
+		if (errfromchild[1] < 0)
+			goto close_fromchild_fail;
+	}
+
 	if (pipe(execfail) != 0)
-		goto close_fromchild_fail;
+		goto close_errfromchild_fail;
 
 	if (fcntl(execfail[1], F_SETFD, fcntl(execfail[1], F_GETFD)
 		  | FD_CLOEXEC) < 0)
@@ -57,54 +101,72 @@ pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, const char *cmd, va_list ap)
 		goto close_execfail_fail;
 
 	if (childpid == 0) {
-		char **args = gather_args(cmd, ap);
-
 		if (fd_tochild)
 			close(tochild[1]);
 		if (fd_fromchild)
 			close(fromchild[0]);
+		if (fd_errfromchild && fd_errfromchild != fd_fromchild)
+			close(errfromchild[0]);
+
 		close(execfail[0]);
 
 		// Child runs command.
-		if (!args)
-			err = ENOMEM;
-		else {
-			if (tochild[0] != STDIN_FILENO) {
-				if (dup2(tochild[0], STDIN_FILENO) == -1)
-					goto child_errno_fail;
-				close(tochild[0]);
-			}
-			if (fromchild[1] != STDOUT_FILENO) {
-				if (dup2(fromchild[1], STDOUT_FILENO) == -1)
-					goto child_errno_fail;
-				close(fromchild[1]);
-			}
-			execvp(cmd, args);
-		child_errno_fail:
-			err = errno;
+		if (tochild[0] != STDIN_FILENO) {
+			if (dup2(tochild[0], STDIN_FILENO) == -1)
+				goto child_errno_fail;
+			close(tochild[0]);
+		}
+		if (fromchild[1] != STDOUT_FILENO) {
+			if (dup2(fromchild[1], STDOUT_FILENO) == -1)
+				goto child_errno_fail;
+			close(fromchild[1]);
+		}
+		if (fd_errfromchild && fd_errfromchild == fd_fromchild) {
+			if (dup2(STDOUT_FILENO, STDERR_FILENO) == -1)
+				goto child_errno_fail;
+		} else if (errfromchild[1] != STDERR_FILENO) {
+			if (dup2(errfromchild[1], STDERR_FILENO) == -1)
+				goto child_errno_fail;
+			close(errfromchild[1]);
+		}
+		execvp(arr[0], arr);
+
+	child_errno_fail:
+		err = errno;
+		/* Gcc's warn-unused-result fail. */
+		if (write(execfail[1], &err, sizeof(err))) {
+			;
 		}
-		write(execfail[1], &err, sizeof(err));
 		exit(127);
 	}
 
 	close(tochild[0]);
 	close(fromchild[1]);
+	close(errfromchild[1]);
 	close(execfail[1]);
 	/* Child will close this without writing on successful exec. */
 	if (read(execfail[0], &err, sizeof(err)) == sizeof(err)) {
+		close(execfail[0]);
 		waitpid(childpid, NULL, 0);
 		errno = err;
 		return -1;
 	}
+	close(execfail[0]);
 	if (fd_tochild)
 		*fd_tochild = tochild[1];
 	if (fd_fromchild)
 		*fd_fromchild = fromchild[0];
+	if (fd_errfromchild)
+		*fd_errfromchild = errfromchild[0];
 	return childpid;
 
 close_execfail_fail:
 	close_noerr(execfail[0]);
 	close_noerr(execfail[1]);
+close_errfromchild_fail:
+	if (fd_errfromchild)
+		close_noerr(errfromchild[0]);
+	close_noerr(errfromchild[1]);
 close_fromchild_fail:
 	if (fd_fromchild)
 		close_noerr(fromchild[0]);
@@ -117,13 +179,14 @@ fail:
 	return -1;
 }
 
-pid_t pipecmd(int *fd_fromchild, int *fd_tochild, const char *cmd, ...)
+pid_t pipecmd(int *fd_tochild, int *fd_fromchild, int *fd_errfromchild,
+	      const char *cmd, ...)
 {
 	pid_t childpid;
 
 	va_list ap;
 	va_start(ap, cmd);
-	childpid = pipecmdv(fd_fromchild, fd_tochild, cmd, ap);
+	childpid = pipecmdv(fd_tochild, fd_fromchild, fd_errfromchild, cmd, ap);
 	va_end(ap);
 
 	return childpid;