Demonstration program of xorriso at two pipes: test/frontend_pipes_xorriso.c

Makefile.am

@@ -244,6 +244,7 @@ EXTRA_DIST = \
 	doc/partition_offset.wiki \
 	doc/qemu_xorriso.wiki \
 	doc/startup_file.txt \
+	test/frontend_pipes_xorriso.c \
 	README \
 	AUTHORS \
 	CONTRIBUTORS \

test/frontend_pipes_xorriso.c

@@ -0,0 +1,230 @@
+
+/* Beefed-up example from man 2 pipe
+   to illustrate how xorriso is to be used by frontend programs via two pipes.
+
+   Build:
+     cc -g -o frontend_pipes_xorriso frontend_pipes_xorriso.c
+
+   Usage:
+     ./frontend_pipes_xorriso [path_to_xorriso_binary]
+
+*/
+
+#include <sys/wait.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+
+/* Local helpers of parent process */
+int await_all_replies(int fd, char *pending_mark);
+int prompt_for_command(char *line, int line_size);
+
+
+/* Parent and child */
+int main(int argc, char *argv[])
+{
+    int command_pipe[2], reply_pipe[2];
+    pid_t cpid;
+    char *xorriso_path = "/usr/bin/xorriso";
+
+    if (argc > 1)
+        xorriso_path = argv[1];
+
+    if (pipe(command_pipe) == -1)
+        { perror("pipe"); exit(1); }
+    if (pipe(reply_pipe) == -1)
+        { perror("pipe"); exit(1); }
+
+    cpid = fork();
+    if (cpid == -1)
+        { perror("fork"); exit(2); }
+
+    if (cpid == 0) {
+        /* Child redirects stdin and stdout. Then it becomes xorriso. */
+
+        char *xargv[8];
+
+        close(command_pipe[1]);        /* Close unused write end */
+        close(reply_pipe[0]);          /* Close unused read end */
+
+        /* Attach pipe ends to stdin and stdout */
+        close(0);
+        if (dup2(command_pipe[0], 0) == -1)
+            { perror("dup2(,0)"); exit(1); }
+        close(1);
+        if (dup2(reply_pipe[1], 1) == -1)
+            { perror("dup2(,1)"); exit(1); }
+
+        xargv[0] = xorriso_path;
+        xargv[1] = "-dialog";
+        xargv[2] = "on";
+        xargv[3] = "-pkt_output";
+        xargv[4] = "on";
+        xargv[5] = "-mark";
+        xargv[6] = "0";       /* corresponds to mark_count = 0 in parent */
+        xargv[7] = NULL;
+        execv(xorriso_path, xargv);
+        perror("execv"); exit(1);
+
+    } else {
+        /* Parent prompts user for command lines and prints xorriso replies.
+           It knows when all reply text of the pending command line has arrived
+           by watching for -mark reply pending_mark. 
+        */
+
+        int mark_count = 0, ret;
+        char pending_mark[16], line[4096];
+
+        close(command_pipe[0]);        /* Close unused read end */
+        close(reply_pipe[1]);          /* Close unused write end */
+
+        /* Dialog loop */
+        sprintf(pending_mark, "%d", mark_count);
+        while (1) {
+
+            /* Wait for pending mark and print all replies */
+            ret = await_all_replies(reply_pipe[0], pending_mark);
+            if (ret < 0)
+        break;
+
+            /* Prompt for command line */
+            ret = prompt_for_command(line, sizeof(line));
+            if (ret <= 0)
+        break;
+
+            /* Send line and -mark command */
+            ret = write(command_pipe[1], line, strlen(line));
+            if (ret == -1) {
+                perror("write");
+        break;
+            }
+            /* Produce new unique -mark text to watch for */
+            mark_count++;
+            sprintf(pending_mark, "%d", mark_count);
+            sprintf(line, "-mark %s\n", pending_mark);
+            ret = write(command_pipe[1], line, strlen(line));
+            if (ret == -1) {
+                perror("write");
+        break;
+            }
+        }
+
+
+        /* >>> if child is still operational: send -rollback_end */;
+
+        /* >>> wait a short while */;
+
+        /* >>> if not yet ended: kill child  */;
+
+        wait(NULL);             /* Wait for child */
+        exit(0);
+    }
+}
+
+
+/* Local helpers of parent process */
+
+
+int await_all_replies(int fd, char *pending_mark)
+{
+    int count, remainder = 0;
+    char buf[32769], *line, *npt;
+
+    while (1) {
+        count = read(fd, buf + remainder, sizeof(buf) - 1 - remainder);
+        if (count == -1) {
+            perror("read");
+            return(-1);
+        }
+        if (count == 0) {
+            fprintf(stderr, "+++ EOF encounterd by Master process\n");
+            return(-2);
+        }
+        for (npt = buf + remainder; npt < buf + count; npt++) {
+             if (*npt == 0) {
+                    fprintf(stderr,
+                            "+++ Protocol error : Reply contains 0-chars\n");
+                    return(-1);
+             }
+        }
+
+        /* Split buf into lines */
+        buf[remainder + count] = 0; /* for convenience */
+        line = buf;
+        while (1) {
+            npt = strchr(line, '\n');
+            if (npt == NULL) {
+                /* Move line to start of buffer and set remainder */
+                if (line != buf) {
+                    remainder = 0;
+                    for (npt = line; *npt; npt++)
+                         buf[remainder++] = *npt;
+                }
+                /* Now read more data in the hope to get a newline char */
+        break;
+            }
+            /* Interpret line */
+            *npt = 0;
+            if (line[0] == 'M') {
+                /* M-replies will be outdated until the pending command line
+                   is completely done and the appended -mark command gets
+                   into effect.
+                */
+                if (strlen(line) < 6) {
+                    fprintf(stderr,
+                 "+++ Protocol error : M-channel line shorter than 6 chars\n");
+                    return(-1);
+                }
+                if (strcmp(line + 5, pending_mark) == 0) {
+                    if ((line - buf) + strlen(line) + 1 < count) {
+                        fprintf(stderr,
+                    "+++ Protocol error : Surplus reply data after M-match\n");
+                        fprintf(stderr, "%s\n", line + strlen(line) + 1);
+                        return(-1);
+                    }
+                    return (1); /* Expected mark has arrived */
+                }
+            } else if (line[0] == 'R') {
+                /* R-replies are result lines of inquiry commands, like -ls.
+                   They should be handled by specialized code which knows
+                   how to parse and interpret them.
+                */
+                printf("%s\n", line);
+            } else {
+                /* I-replies are pacifiers, notifications, warnings, or
+                   error messages. They should be handled by a general
+                   message interpreter which determines their severity
+                   and decides whether to bother the user.
+                */
+                fprintf(stderr, "%s\n", line);
+            }
+            line = npt + 1;
+        }
+    }
+    return(1);
+}
+
+
+int prompt_for_command(char *line, int line_size)
+{
+    int l;
+    char *line_res;
+
+    fprintf(stderr, "+++ Enter a command and its parameters :\n");
+    line_res = fgets(line, line_size - 1, stdin);
+    if (line_res == NULL)
+        return(0);
+    l = strlen(line);
+    if (l == 0) {
+        line[0] = '\n';
+        line[1] = 0;
+    } else if (line[l - 1] != '\n') {
+        line[l] = '\n';
+        line[l + 1] = 0;
+    }
+    return(1);
+}
+

xorriso/make_xorriso_standalone.sh

@@ -231,7 +231,8 @@ copy_files doc/partition_offset.wiki \
 create_dir "$lone_dir"/test
 copy_files \
  test/compare_file.c \
- "$lone_dir"/test/compare_file.c
+ test/frontend_pipes_xorriso.c \
+ "$lone_dir"/test
 
 
 # releng

xorriso/xorriso_makefile_am.txt

@@ -1,5 +1,5 @@
 
-# Copyright (c) 2007 - 2010 Thomas Schmitt <scdbackup@gmx.net>
+# Copyright (c) 2007 - 2012 Thomas Schmitt <scdbackup@gmx.net>
 # Provided under GPL version 2 or later.
 
 # ts A90315 : LIBBURNIA_PKGCONFDIR is defined OS specific in acinclude.m4
@@ -328,6 +328,7 @@ EXTRA_DIST = \
 	doc/susp_aaip_isofs_names.txt \
 	doc/zisofs_format.txt \
 	doc/startup_file.txt \
+	test/frontend_pipes_xorriso.c \
 	libisofs/aaip-os-dummy.c \
 	libisofs/aaip-os-linux.c \
 	libisofs/aaip-os-freebsd.c \

xorriso/xorriso_timestamp.h

@@ -1 +1 @@
-#define Xorriso_timestamP "2012.09.08.181144"
+#define Xorriso_timestamP "2012.09.09.181723"