job.c

#include "job.h"
#include "global.h"

/* initializes the job list data structure */
void init_job(IronShellJob *job, char *command) {
    job->head = job->tail = NULL;
    strcpy(job->command, command);
    job->process_count = 0;
    job->command_status = RUNNING;
    return;
}

/* adds sub job to the exisition job list data structure */
void add_sub_job(IronShellJob *job, char *command_name, pid_t pid) {
    IronShellJobProcess *new_sub_job = 
        (IronShellJobProcess *)malloc(sizeof(IronShellJobProcess));
    if(new_sub_job == NULL) {
        PRINT_ERR("malloc failed");
    }
    strcpy(new_sub_job->process_name, command_name);
    new_sub_job->pid = pid;
    new_sub_job->next = NULL;
    
    /* first job to the added in the list */
    if(job->head == NULL && job->tail == NULL) {
        job->head = job->tail = new_sub_job; 
        job->process_count++;
        return;
    }
    new_sub_job->next = job->head;
    job->head = new_sub_job;
    job->process_count++;
    return;
}

/* void traverse the job list */
void traverse_job(IronShellJob job) {
    IronShellJobProcess *ptr = job.head;
    while(ptr != NULL) {
        printf("(%s, %d)\t", ptr->process_name, ptr->pid);
        ptr = ptr->next;
    }
    printf("\n");
    return;
}

/* destories the job and allocated resources */
void destroy_job(IronShellJob* job) {
    IronShellJobProcess *ptr = job->head, *temp;
    while(ptr != NULL) {
        temp = ptr->next; 
        free(ptr);
        ptr = temp;
    }
    job->head = job->tail = NULL;
    job->process_count = 0;
    return;
}

/* kills the job's running process 
 * Note : this frees the dynamically allocated resources 
 */
void kill_job(IronShellJob *job) {
    IronShellJobProcess *ptr = job->head;
    while(ptr != NULL) {
        kill(ptr->pid, SIGINT); 
        ptr = ptr->next;
    }
    destroy_job(job);
    return;
}

/* suspends the job's running processes 
 * Note this doesn't free the dynamically allocated resources 
 */
void suspend_job(IronShellJob *job) {
    IronShellJobProcess *ptr = job->head;
    while(ptr != NULL) {
        kill(ptr->pid, SIGSTOP);
        ptr = ptr->next;
    }
    job->command_status = STOPPED;
    print_job(*job, iscb.jobs.count_jobs + 1);
    return;
}

/* resumes the execution of the job and since any paritcular 
 * job contains many process thus execution all process is resumed.
 */
void resume_job(IronShellJob *job, int index) {
    IronShellJobProcess *ptr = job->head;
    if(ptr == NULL) {
        PRINT_EXECPTION("job has no associated processes");
        return;
    } 
    while(ptr != NULL) {
        kill(ptr->pid, SIGCONT);
        ptr = ptr->next; 
    }
    job->command_status = RUNNING;
    print_job(*job, index);
    return;
}

/* logs the message on the prompt regarding the job which is stopped or running
 */
void print_job(IronShellJob job, int index) {
    IronShellJobProcess *ptr = job.head;
    if(ptr == NULL) {
        PRINT_EXECPTION("job has no associated processes");
        return;
    }
    if(job.command_status == STOPPED) {
        PRINT_JOB_PROCESS_HEAD(index, ptr->pid, ptr->process_name, "stopped");
    } else {
        PRINT_JOB_PROCESS_HEAD(index, ptr->pid, ptr->process_name, "running");
    }
    ptr = ptr->next;
    while(ptr != NULL) {
        if(job.command_status == STOPPED) {
            PRINT_JOB_PROCESS_NODE(ptr->pid, ptr->process_name, "stopped");
        } else {
            PRINT_JOB_PROCESS_NODE(ptr->pid, ptr->process_name, "running");
        }
        ptr = ptr->next;
    }
    return;
}

/* deletes a sub job process with given pid                                 */
bool delete_sub_job(IronShellJob *jobs, pid_t pid, int index) {
    IronShellJobProcess *ptr = jobs->head, *temp = NULL;
    while(ptr != NULL) {
        if(ptr->pid == pid) {
            /* you need to delete this particular node from the list */ 
            if(temp == NULL) {
                jobs->head = ptr->next;
                if(jobs->head == NULL) {
                    jobs->tail = NULL;
                }
            } else {
                temp->next = ptr->next;
            }
            PRINT_JOB_DONE(index, pid, ptr->process_name);
            free(ptr);
            jobs->process_count--;
            return true;
        } 
        temp = ptr;
        ptr = ptr->next;
    }
    return false;
}