1 files changed, 232 insertions, 0 deletions
diff --git a/pgm3/report.c b/pgm3/report.c
new file mode 100644
index 0000000..623de6f
--- /dev/null
+++ b/pgm3/report.c
@@ -0,0 +1,232 @@
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <unistd.h>
+
+#define FALSE 0
+#define FILE_BUFF 4096
+#define TRUE  1
+
+int terminateFlag = 1; // Used with signal handler function.
+
+void sigHandler(int signum) {
+    /*
+     * sigHandler() waits for a SIGUSR1 signal. Upon receiving this signal it
+     * decrements terminateFlag, lowering it to zero.
+     */
+
+    if (signum == SIGUSR1) {
+        terminateFlag--;
+    }
+
+}
+
+int main(int argc, char *argv[]) {
+    /*
+     * report takes in one required argument ("num") and two optional arguments.
+     * -k specifies that output should be printed in kilobytes, not bytes
+     * -d specifies a delay that should be waited before reading each filename
+     * into the totalsize child process.
+     *
+     * Report takes in filenames on its stdin and then calls four child
+     * processes. Two execute accessed, one with num as an arg and one with
+     * -num as an arg. report writes its stdin to the stdin of the accessed
+     * children. The accessed children then print their output to the stdin
+     * of two more children that execute totalsize. These totalsize
+     * children run through the filenames they're given and print out the
+     * size of those files back into report. This is all done via pipes.
+     *
+     * report then prints out the results it receives from its children.
+     */
+    char byteSum[10];
+    char delayStr[10];
+    char *envar = NULL;
+    char filename[FILE_BUFF];
+    char numNeg[11];
+    char thisPID[10];
+    int accessedNum;
+    int delay = 0;
+    int i = 2;
+
+    // Go through args.
+    if (argc < 2) {
+        fprintf(stderr, "usage: ./report [num days] {-k} {-d} [delay]\n");
+        exit(1);
+    }
+
+    // Fetch accessedNum parameter
+    accessedNum = strtol(argv[1], NULL, 10);
+    errno = 0;
+
+    if (accessedNum <= 0) {
+        fprintf(stderr, "report: num must be positive, nonzero integer.\n");
+        exit(1);
+    }
+    else if (errno == ERANGE) {
+        fprintf(stderr, "report: num must be of integer size.\n");
+        exit(1);
+    }
+    else if (errno == EINVAL) {
+        fprintf(stderr, "report: num must be integer type.\n");
+        exit(1);
+    }
+
+    // Set the second accessed num as negative.
+    sprintf(numNeg, "%d", accessedNum * -1);
+
+    while (argv[i]) {
+
+        if (strcmp(argv[i], "-k") == 0) {
+            setenv("UNITS", "k", 1);
+        }
+        else if (strcmp(argv[i], "-d") == 0) {
+            delay = strtol(argv[i+1], NULL, 10);
+            errno = 0;
+
+            if (delay <= 0) {
+                fprintf(stderr, "report: delay must be positive, nonzero integer.\n");
+                exit(1);
+            }
+            else if (errno == ERANGE) {
+                fprintf(stderr, "report: delay must be of integer size.\n");
+                exit(1);
+            }
+            else if (errno == EINVAL) {
+                fprintf(stderr, "report: delay must be integer type.\n");
+                exit(1);
+            }
+
+            sprintf(delayStr, "%d", delay);
+            setenv("TSTALL", delayStr, 1);
+            i++;
+        }
+        else {
+            fprintf(stderr, "usage: ./report [num days] {-k} {-d} [delay]\n");
+            exit(1);
+        }
+
+        i++;
+    }
+
+    // Set up signal handling.
+    sprintf(thisPID, "%d", getpid());
+    setenv("TMOM", thisPID, 1);
+    signal(SIGUSR1, sigHandler);
+
+    // Set up pipes.
+    int pipeRtoA1[2]; pipe(pipeRtoA1);
+    int pipeRtoA2[2]; pipe(pipeRtoA2);
+    int pipeA1toT1[2]; pipe(pipeA1toT1);
+    int pipeA2toT2[2]; pipe(pipeA2toT2);
+    int pipeT1toR[2]; pipe(pipeT1toR);
+    int pipeT2toR[2]; pipe(pipeT2toR);
+
+    if (fork() == 0) { // accessed 1
+        // Close unneeded pipes =====================
+                                close(pipeRtoA1[1]);
+        close(pipeRtoA2[0]);    close(pipeRtoA2[1]);
+        close(pipeA1toT1[0]);
+        close(pipeA2toT2[0]);   close(pipeA2toT2[1]);
+        close(pipeT1toR[0]);    close(pipeT1toR[1]);
+        close(pipeT2toR[0]);    close(pipeT2toR[1]);
+        // ==========================================
+
+        // Dup read end to stdin and write end to stdout
+        close(0); dup(pipeRtoA1[0]); close(pipeRtoA1[0]);
+        close(1); dup(pipeA1toT1[1]); close(pipeA1toT1[1]);
+        execl("accessed", "accessed", argv[1], NULL);
+    }
+    else if (fork() == 0) { // accessed 2
+        // Close unneeded pipes =====================
+        close(pipeRtoA1[0]);    close(pipeRtoA1[1]);
+                                close(pipeRtoA2[1]);
+        close(pipeA1toT1[0]);   close(pipeA1toT1[1]);
+        close(pipeA2toT2[0]);
+        close(pipeT1toR[0]);    close(pipeT1toR[1]);
+        close(pipeT2toR[0]);    close(pipeT2toR[1]);
+        // ==========================================
+
+        close(0); dup(pipeRtoA2[0]); close(pipeRtoA2[0]);
+        close(1); dup(pipeA2toT2[1]); close(pipeA2toT2[1]);
+        execl("accessed", "accessed", numNeg, NULL);
+    }
+    else if (fork() == 0) { // totalsize 1
+        // Close unneeded pipes =====================
+        close(pipeRtoA1[0]);    close(pipeRtoA1[1]);
+        close(pipeRtoA2[0]);    close(pipeRtoA2[1]);
+                                close(pipeA1toT1[1]);
+        close(pipeA2toT2[0]);   close(pipeA2toT2[1]);
+        close(pipeT1toR[0]);
+        close(pipeT2toR[0]);    close(pipeT2toR[1]);
+        // ==========================================
+
+        close(0); dup(pipeA1toT1[0]); close(pipeA1toT1[0]);
+        close(1); dup(pipeT1toR[1]); close(pipeT1toR[1]);
+        execl("totalsize", "totalsize", NULL);
+    }
+    else if (fork() == 0) { // totalsize 2
+        // Close unneeded pipes =====================
+        close(pipeRtoA1[0]);    close(pipeRtoA1[1]);
+        close(pipeRtoA2[0]);    close(pipeRtoA2[1]);
+        close(pipeA1toT1[0]);   close(pipeA1toT1[1]);
+                                close(pipeA2toT2[1]);
+        close(pipeT1toR[0]);    close(pipeT1toR[1]);
+        close(pipeT2toR[0]);
+        // ==========================================
+
+        close(0); dup(pipeA2toT2[0]); close(pipeA2toT2[0]);
+        close(1); dup(pipeT2toR[1]); close(pipeT2toR[1]);
+        execl("totalsize", "totalsize", NULL);
+    }
+
+    // Close those pipes which parent report does not need
+    close(pipeRtoA1[0]);
+    close(pipeRtoA2[0]);
+    close(pipeA1toT1[0]);   close(pipeA1toT1[1]);
+    close(pipeA2toT2[0]);   close(pipeA2toT2[1]);
+                            close(pipeT1toR[1]);
+                            close(pipeT2toR[1]);
+
+    // Write stdin from report to accessed children
+    while (scanf("%s", filename) == 1) {
+        write(pipeRtoA1[1], strcat(filename, " "), strlen(filename) + 1);
+        write(pipeRtoA2[1], strcat(filename, " "), strlen(filename) + 1);
+    }
+
+    // Close remaining pipes.
+    close(pipeRtoA1[1]);    close(pipeRtoA2[1]);
+
+    // Enter non-terminating loop to wait for children
+    while (terminateFlag) {
+        printf("*");
+        sleep(1);
+    }
+
+    // Print results of first totalsize child
+    read(pipeT1toR[0], byteSum, sizeof(byteSum)); close(pipeT1toR[0]);
+    sscanf(byteSum, " %s ", byteSum);
+    printf("\nA total of %s ", byteSum);
+
+    if ((envar = getenv("UNITS")) == NULL || !(envar[0] != 'k' || envar[0] != 'K')) {
+        printf("bytes ");
+    }
+
+    printf("are in regular files not accessed for %s days.\n----------\n", argv[1]);
+
+    // Print results of second totalsize child
+    read(pipeT2toR[0], byteSum, sizeof(byteSum)); close(pipeT2toR[0]);
+    sscanf(byteSum, " %s ", byteSum);
+    printf("A total of %s ", byteSum);
+
+    if ((envar = getenv("UNITS")) == NULL || !(envar[0] != 'k' || envar[0] != 'K')) {
+        printf("bytes ");
+    }
+
+    printf("are in regular files accessed within %s days.\n\n", argv[1]);
+    exit(0);
+}