init commit

3sem/cnts/contest13/03.c

@@ -0,0 +1,92 @@
+#include <unistd.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+enum
+{
+    ACCESS_FILE = 0660
+};
+
+int
+main(int argc, char **argv)
+{
+    char *cmd1 = argv[1];
+    char *cmd2 = argv[2];
+    char *cmd3 = argv[3];
+    char *file1 = argv[4];
+    char *file2 = argv[5];
+
+    int fd1 = open(file1, O_RDONLY);
+    int fd2 = open(file2, O_WRONLY | O_APPEND | O_CREAT, ACCESS_FILE);
+    if (fd1 == -1 || fd2 == -1) {
+        exit(1);
+    }
+
+    int fd[2];
+    if (pipe(fd) == -1) {
+        return 1;
+    }
+
+    pid_t pid = fork();
+    if (pid == 0) {
+        close(fd[0]);
+        if (dup2(fd[1], 1) == -1) {
+            _exit(1);
+        }
+
+        pid = fork();
+        if (pid == 0) {
+
+            if (dup2(fd1, 0) == -1) {
+                _exit(1);
+            }
+
+            execlp(cmd1, cmd1, NULL);
+            _exit(1);
+        } else if (pid == -1) {
+            exit(1);
+        }
+
+        int status;
+        wait(&status);
+
+        if (WIFEXITED(status) && !WEXITSTATUS(status)) {
+            pid = fork();
+            if (pid == 0) {
+                execlp(cmd2, cmd2, NULL);
+                _exit(1);
+            } else if (pid == -1) {
+                exit(1);
+            }
+
+            wait(NULL);
+        }
+
+        _exit(0);
+    } else if (pid == -1) {
+        exit(1);
+    }
+
+    close(fd[1]);
+    pid = fork();
+    if (pid == 0) {
+
+        if (dup2(fd2, 1) == -1 || dup2(fd[0], 0)) {
+            _exit(1);
+        }
+
+        execlp(cmd3, cmd3, NULL);
+        _exit(1);
+    } else if (pid == -1) {
+        exit(1);
+    }
+
+    close(fd[0]);
+
+    while (wait(NULL) != -1)
+        ;
+    return 0;
+}