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authorStefan Zabka <zabkaste@hu-berlin.de>2020-05-13 20:38:21 +0200
committerStefan Zabka <zabkaste@hu-berlin.de>2020-05-13 20:38:21 +0200
commit08d6167988a0bbec72d84ff12f8857f0b4d0b42a (patch)
tree70bbe9b77990424e5868b5b373ffc58f34448bb1
parent0cc3a2176bd396a35f44fcc28ec916b41f019e16 (diff)
downloadbetriebssysteme-08d6167988a0bbec72d84ff12f8857f0b4d0b42a.tar.gz
betriebssysteme-08d6167988a0bbec72d84ff12f8857f0b4d0b42a.zip
Changing dirs kinda works
-rw-r--r--02_exercise/beispiele/pipe_bidirect/pingpong.c205
-rw-r--r--02_exercise/shell.c52
2 files changed, 147 insertions, 110 deletions
diff --git a/02_exercise/beispiele/pipe_bidirect/pingpong.c b/02_exercise/beispiele/pipe_bidirect/pingpong.c
index ac5eb1c..f38394f 100644
--- a/02_exercise/beispiele/pipe_bidirect/pingpong.c
+++ b/02_exercise/beispiele/pipe_bidirect/pingpong.c
@@ -1,124 +1,125 @@
+#include <fcntl.h>
+#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
-#include <fcntl.h>
#include <unistd.h>
static int split(int fd[2]);
-static int redir(int fd, const char* file);
+static int redir(int fd, const char *file);
static void sig_handler(int sig);
static int parent;
int main(void) {
- ssize_t bytes;
- char buf[256];
- int fd[2];
-
- // disable buffering for stdout
- setvbuf(stdout, NULL, _IONBF, 0);
-
- // redirect stdout to write into a file
- if (redir(1, "log.txt") < 0) {
- perror("redir()");
- exit(-1);
- }
-
- // install the signal handler for Ctrl+C
- if (signal(SIGINT, sig_handler) == SIG_ERR) {
- perror("signal()");
- exit(-1);
- }
-
- // split processes and assign file descriptors for communication
- switch (split(fd)) {
- case -1: // error
- exit(-1);
-
- case 0: // child
- while ((bytes = read(fd[0], buf, sizeof(buf))) > 0) {
- printf("[%u]: %s\n", getpid(), buf);
- sleep(1);
- write(fd[1], "pong", 5);
- }
- break;
-
- case 1: // parent
- parent = 1;
- write(fd[1], "ping", 5);
- while ((bytes = read(fd[0], buf, sizeof(buf))) > 0) {
- printf("[%u]: %s\n", getpid(), buf);
- sleep(1);
- write(fd[1], "ping", 5);
- }
- break;
- }
-
- // close the file descriptors
- close(fd[0]);
- close(fd[1]);
-
- return 0;
+ ssize_t bytes;
+ char buf[256];
+ int fd[2];
+
+ // disable buffering for stdout
+ setvbuf(stdout, NULL, _IONBF, 0);
+
+ // redirect stdout to write into a file
+ if (redir(1, "log.txt") < 0) {
+ perror("redir()");
+ exit(-1);
+ }
+
+ // install the signal handler for Ctrl+C
+ if (signal(SIGINT, sig_handler) == SIG_ERR) {
+ perror("signal()");
+ exit(-1);
+ }
+
+ // split processes and assign file descriptors for communication
+ switch (split(fd)) {
+ case -1: // error
+ exit(-1);
+
+ case 0: // child
+ while ((bytes = read(fd[0], buf, sizeof(buf))) > 0) {
+ printf("[%u]: %s\n", getpid(), buf);
+ sleep(1);
+ write(fd[1], "pong", 5);
+ }
+ break;
+
+ case 1: // parent
+ parent = 1;
+ write(fd[1], "ping", 5);
+ while ((bytes = read(fd[0], buf, sizeof(buf))) > 0) {
+ printf("[%u]: %s\n", getpid(), buf);
+ sleep(1);
+ write(fd[1], "ping", 5);
+ }
+ break;
+ }
+
+ // close the file descriptors
+ close(fd[0]);
+ close(fd[1]);
+
+ return 0;
}
int split(int fd[2]) {
- int pfd[2][2];
-
- if (pipe(pfd[0]) < 0) {
- perror("pipe()");
- goto err_pipe1;
- }
-
- if (pipe(pfd[1]) < 0) {
- perror("pipe()");
- goto err_pipe2;
- }
-
- switch (fork()) {
- case -1:
- perror("fork()");
- goto err_fork;
-
- case 0: // child process
- close(pfd[0][1]); // close write for child
- close(pfd[1][0]); // close read for parent
- fd[0] = pfd[0][0]; // keep read for child
- fd[1] = pfd[1][1]; // keep write for parent
- return 0;
-
- default: // parent process
- close(pfd[1][1]); // close write for parent
- close(pfd[0][0]); // close read for child
- fd[0] = pfd[1][0]; // keep read for parent
- fd[1] = pfd[0][1]; // keep write for child
- return 1;
- }
-
+ int pfd[2][2];
+
+ if (pipe(pfd[0]) < 0) {
+ perror("pipe()");
+ goto err_pipe1;
+ }
+
+ if (pipe(pfd[1]) < 0) {
+ perror("pipe()");
+ goto err_pipe2;
+ }
+
+ switch (fork()) {
+ case -1:
+ perror("fork()");
+ goto err_fork;
+
+ case 0: // child process
+ close(pfd[0][1]); // close write for child
+ close(pfd[1][0]); // close read for parent
+ fd[0] = pfd[0][0]; // keep read for child
+ fd[1] = pfd[1][1]; // keep write for parent
+ return 0;
+
+ default: // parent process
+ close(pfd[1][1]); // close write for parent
+ close(pfd[0][0]); // close read for child
+ fd[0] = pfd[1][0]; // keep read for parent
+ fd[1] = pfd[0][1]; // keep write for child
+ return 1;
+ }
+
err_fork:
- close(pfd[1][0]);
- close(pfd[1][1]);
+ close(pfd[1][0]);
+ close(pfd[1][1]);
err_pipe2:
- close(pfd[0][0]);
- close(pfd[0][1]);
+ close(pfd[0][0]);
+ close(pfd[0][1]);
err_pipe1:
- return -1;
+ return -1;
}
-int redir(int fd, const char* file) {
- int fd2 = open(file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
-
- if (fd2 < 0)
- return -1;
-
- dup2(fd2, fd);
- close(fd2);
-
- return 0;
+int redir(int fd, const char *file) {
+ int fd2 = open(file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+
+ if (fd2 < 0)
+ return -1;
+
+ dup2(fd2, fd);
+ close(fd2);
+
+ return 0;
}
void sig_handler(int sig) {
- if (parent) {
- const char msg[] = "Programmabbruch durch Nutzer\n";
- write(1, msg, sizeof(msg) - 1);
- }
- exit(0);
+ if (parent) {
+ const char msg[] = "Programmabbruch durch Nutzer\n";
+ write(1, msg, sizeof(msg) - 1);
+ }
+ exit(0);
}
diff --git a/02_exercise/shell.c b/02_exercise/shell.c
index 88b17fd..2594d6b 100644
--- a/02_exercise/shell.c
+++ b/02_exercise/shell.c
@@ -10,12 +10,16 @@
#include <unistd.h>
#include "array.h"
+#include "errno.h"
#include "stdbool.h"
void print_prompt(char const *const original_wd, char const *current_wd);
-int main(void) {
+// Returns the return code of the executed programm
+int exec_command(char *command);
+int main(void) {
+ // the directory is specified without a / at the end
char const *const original_wd = get_current_dir_name();
char const *current_wd = get_current_dir_name();
@@ -23,12 +27,21 @@ int main(void) {
char *command = NULL;
size_t cap = 0;
size_t length = 0;
+
print_prompt(original_wd, current_wd);
if ((length = getline(&command, &cap, stdin)) < 0) {
fprintf(stderr, "Failed to read from STDIN");
+ exit(-1);
}
- if (strcmp(command, "exit\n") == 0) {
+ if (strstr(command, "cd") != NULL) {
+ printf("Changing dirs \n");
+ chdir("beispiele");
+ free((void *) current_wd);
+ current_wd = get_current_dir_name();
+ } else if (strcmp(command, "exit\n") == 0) {
exit(0);
+ } else {
+ exec_command(command);
}
free((void *)command);
}
@@ -37,10 +50,33 @@ int main(void) {
free((void *)current_wd);
}
-void print_prompt(char const *const original_wd, char const *current_wd) {
-
- int result = strcmp(original_wd, current_wd);
- if (result == 0) {
- printf("./ > ");
+void print_prompt(char const *const original_wd, char const *const current_wd) {
+ // easiest case first
+ {
+ int result = strcmp(original_wd, current_wd);
+ if (result == 0) {
+ printf(".> ");
+ return;
+ }
}
-} \ No newline at end of file
+ printf("%s > ", current_wd);
+ // Now checking for substrings aka are we in a subdir
+ {
+ size_t dirlen = strlen(original_wd);
+ char *const orig_dir_with_slash = malloc(dirlen + 2);
+ if (orig_dir_with_slash == NULL) {
+ fprintf(stderr, "Failed to allocate for prompt");
+ exit(ENOMEM);
+ }
+ memcpy(orig_dir_with_slash, original_wd, dirlen);
+ orig_dir_with_slash[dirlen] = '/';
+ orig_dir_with_slash[dirlen + 1] = '\0';
+ char const *const result = strstr(current_wd, original_wd);
+ if (result != NULL) {
+ printf(".%s > ", current_wd + dirlen);
+ return;
+ }
+ }
+}
+
+int exec_command(char *command) { return 0; }