expand.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <dirent.h>
#include <pwd.h>
#include <errno.h>
#include "proto.h"

#define BUF_SIZE 256

static int expLiteralChars(char *orig, char *new, int *oldl_ind, int *newl_ind, int *insideQuoteFlag)
{
    if(orig[*oldl_ind] == '"') *insideQuoteFlag = !(*insideQuoteFlag);
    new[*newl_ind] = orig[*oldl_ind];
    (*newl_ind)++;
    (*oldl_ind)++;
    return 0;
}

static int expEnvVars(char *orig, char *new, int *oldl_ind, int *newl_ind)
{
    char *envValue;
    int envNameLen = 0;

    (*oldl_ind)++;
    while(orig[*oldl_ind + envNameLen] != '}')
    {
        if(orig[*oldl_ind + envNameLen] == 0 || orig[*oldl_ind + envNameLen] == '$')
        {
            fprintf(stderr, "msh: no matching }\n");
            return 1;
        }
        envNameLen++;
    }

    orig[*oldl_ind + envNameLen] = 0;
    envValue = getenv(&(orig[*oldl_ind]));


    if(envValue != NULL)
    {
        strcpy(&(new[*newl_ind]), envValue);
        *newl_ind = *newl_ind + strlen(envValue);
    }

    *oldl_ind = *oldl_ind + envNameLen + 1;
    // envNameLen = 0;
    return 0;
}

static int expShPid(char *orig, char *new, int *oldl_ind, int *newl_ind)
{
    char pidBuff[8];
    int pid = (int)getpid();
    int i = 0;

    if(sprintf(pidBuff, "%d", pid) > -1)
    {
        while(pidBuff[i])
        {
            new[*newl_ind] = pidBuff[i++];
            (*newl_ind)++;
        }
        (*oldl_ind)++;
        return 0;
    }
    return 1;
}

static int expMainArgs(char *orig, char *new, int *oldl_ind, int *newl_ind) //, int mainargc, char **mainargv, char **shiftedMArgV)
{
    int argInd;
    int argLen;
    char tempChar;
    char *argIndStr = &(orig[*oldl_ind]);

    while(isdigit(orig[*oldl_ind])) (*oldl_ind)++;

    tempChar = orig[(*oldl_ind)];
    orig[*oldl_ind] = 0;
    argInd = atoi(argIndStr);
    orig[*oldl_ind] = tempChar;


    if(m_argc == 1)
    {
        if(argInd >= m_shifted_argc) return 0;
        argLen = strlen(m_argv[0]);
        strcpy(&(new[*newl_ind]), m_argv[0]);
    }
    else
    {
        if((argInd+1) >= m_shifted_argc) return 0;
        if(argInd == 0)
        {
            argLen = strlen(m_argv[1]);
            strcpy(&(new[*newl_ind]), m_argv[1]);
        }
        else
        {
            argLen = strlen(m_shifted_argv[argInd+1]);
            strcpy(&(new[*newl_ind]), m_shifted_argv[argInd+1]);
        }
    }

    *newl_ind = *newl_ind + argLen;
    return 0;
}

static int expMainCount(char *new, int *newl_ind) //, int mainargc)
{
    int argStrLen;
    int offset = 1;

    if(m_argc == 1) offset = 0;

    argStrLen = sprintf(&(new[*newl_ind]), "%d", (m_shifted_argc - offset));

    *newl_ind = *newl_ind + argStrLen;

    return 0;
}

static int expLastExitS(char *new, int *newl_ind)
{
    int exStatStrLen = sprintf(&(new[*newl_ind]), "%d", (last_exit_status));

    *newl_ind = *newl_ind + exStatStrLen;

    return 0;
}

static int expWildCard(char *orig, char *new, int *oldl_ind, int *newl_ind, int filterFlag)
{
    int i;
    int dirLen;
    int matchCount = 0;
    int passedFilterFlag = 0;
    int dirNameStrLen;
    char *dirName;
    char *filterStr;
    char tempChar;
    struct dirent **namelist;

    /* GET ALL THE DIRECTORIES AND PUT THEM IN namelist */
    dirLen = scandir(".", &namelist, 0, alphasort);
    if(dirLen < 0)
    {
        perror("scandir");
        return 1;
    }

    (*oldl_ind)++;
    if(filterFlag)
    {
        filterStr = &(orig[*oldl_ind]);
        while(orig[*oldl_ind] != ' ' && orig[*oldl_ind] != '"' && orig[*oldl_ind] != 0)
        {
            if(orig[*oldl_ind] == '/')
            {
                fprintf(stderr, "./msh: no match\n");
                return 1;
            }
            (*oldl_ind)++;
        }
        tempChar = orig[*oldl_ind];
        orig[*oldl_ind] = 0;
    }

    for(i = 0; i < dirLen; i++)
    {
        dirName = namelist[i]->d_name;
        dirNameStrLen = strlen(dirName);

        if(dirName[0] == '.')
        {
            passedFilterFlag = 0;
        }
        else if(filterFlag)
        {
            if(strlen(filterStr) > dirNameStrLen) passedFilterFlag = 0;
            else
            {
                if(!strcmp(filterStr, &(dirName[dirNameStrLen - strlen(filterStr)]))) passedFilterFlag = 1;
                else passedFilterFlag = 0;
            }
        }
        else passedFilterFlag = 1;

        if(passedFilterFlag)
        {
            matchCount++;
            strcpy(&(new[*newl_ind]), dirName);
            if(i != (dirLen -1))
            {
                *newl_ind = *newl_ind + dirNameStrLen + 1;
                new[*newl_ind - 1] = ' ';
            }
            else *newl_ind = *newl_ind + dirNameStrLen;
        }

        free(namelist[i]);
    }

    if(!matchCount)
    {
        new[*newl_ind] = '*';
        (*newl_ind)++;
        if(filterFlag)
        {
            strcpy(&(new[*newl_ind]), filterStr);
            *newl_ind = *newl_ind + strlen(filterStr);
        }
    }

    if(filterFlag) orig[*oldl_ind] = tempChar;
    free(namelist);
    return 0;
}

static int expHomeDir(char *orig, char *new, int *oldl_ind, int *newl_ind)
{
    int i = 1;
    char temp;
    char *name = 0;
    char *hdir;
    struct passwd *pwResult;

    /* SEE IF NAME PRESENT AFTER ~ AND PUT NULL TERMINATOR AT END IF THERE IS
       IF NOT USE getlogin */
    while(orig[*oldl_ind + i] != ' ' && orig[*oldl_ind + i] != '/' && orig[*oldl_ind + i] != 0) i++;
    temp = orig[*oldl_ind +i];
    if(i == 1) name = getlogin();
    else
    {
        orig[*oldl_ind + i] = 0;
        name = &(orig[*oldl_ind + 1]);
    }

    /* GET PASSWD RESULTS, REPLACE NULL(OR NOTHING) WITH TEMP */
    pwResult = getpwnam(name);
    orig[*oldl_ind + i] = temp;

    /* UPDATE IND'S. IF THERE ARE NO PASSWD RESULTS, LEAVE LITERAL
       TILDA, OTHERWISE COPY HOME FOLDER TO NEW. */
    if(!pwResult)
    {
        new[*newl_ind] = '~';
        *oldl_ind = *oldl_ind + 1;
        *newl_ind = *newl_ind + 1;
    }
    else
    {
        hdir = pwResult->pw_dir;
        strcpy(&(new[*newl_ind]), hdir);

        *oldl_ind = *oldl_ind + i;
        *newl_ind = *newl_ind + strlen(hdir);
    }

    return 0;
}

static int expCmdOutput(char *orig, char *new, int *oldl_ind, int *newl_ind)
{
    char buf[BUF_SIZE];
    int bytes_read;
    int total_bytes_read = 0;
    int fd[2];
    int parenthCount = 1;
    int i = *oldl_ind + 1;

    /* ENSURE MATCHING PARENS - REPLACE LAST PAREN WITH 0 */
    while(parenthCount > 0)
    {
        if(orig[i] == '(') parenthCount++;
        else if(orig[i] == ')') parenthCount--;
        else if(orig[i] == 0)
        {
            fprintf(stderr, "./msh: missing )\n");
            return 1;
        }
        i++;
    }
    orig[i-1] = 0;

    /* PIPE, RECURSIVELY CALL PROCESSLINE(should pass 0 for 3rd arg), AND CLOSE WRITE END */
    if(pipe (fd) < 0) perror("pipe");
    processline(&(orig[*oldl_ind + 1]), fd[1], 0);
    close(fd[1]);

    /* READ OUTPUT OF COMMAND FROM READ END OF PIPE, THEN CLOSE READ END */
    while((bytes_read = read(fd[0],buf,BUF_SIZE-1)))
    {
        if(bytes_read < 0)
        {
            if(errno == EWOULDBLOCK || errno == EAGAIN) continue;
            else if(errno == EINTR) fprintf(stderr, "WE GOT AN EINTR SIGNAL\n");
            else
            {
                perror("read");
                break; // Or should this be exit?
            }
        }
        else if(bytes_read > 0) total_bytes_read += bytes_read;
    }
    buf[total_bytes_read] = 0;
    close(fd[0]);

    /* REPLACE ORIGINAL MATCHING PAREN, UPDATE oldl_ind */
    orig[i-1] = ')';
    *oldl_ind = i;

    /* COPY OUTPUT OF COMMAND TO EXPANDED LINE, UPDATE newl_ind */
    i = 0;
    while(buf[i] != 0)// && buf[i] != '\n')
    {
        new[*newl_ind + i] = buf[i];
        i++;
    }
    *newl_ind = *newl_ind + i;

    /* REMOVING EXTRA LINES */
    i = 0;
    while(new[i])
    {
        if(new[i] == '\n') new[i] = ' ';// && new[i+1] != 0) new[i] = ' ';
        i++;
    }

    return 0;
}

int expand(char *orig, char *new, int newsize) //, int mainargc, char **mainargv, char **shiftedMArgV)
{
    int newl_ind = 0;
    int oldl_ind = 0;
    int insideQuoteFlag = 0;

    while(orig[oldl_ind] && newl_ind < newsize)
    {
        if(orig[oldl_ind] == '$')
        {
            if(orig[++oldl_ind] == '{') { if(expEnvVars(orig, new, &oldl_ind, &newl_ind)) return 1; }
            else if(orig[oldl_ind] == '(') { if(expCmdOutput(orig, new, &oldl_ind, &newl_ind)) return 1; }
            else if(orig[oldl_ind] == '$') { if(expShPid(orig, new, &oldl_ind, &newl_ind)) return 1; }
            else if(isdigit(orig[oldl_ind])) { if(expMainArgs(orig, new, &oldl_ind, &newl_ind)) return 1; } //, mainargc, mainargv, shiftedMArgV)) return 1; }
            else if(orig[oldl_ind] == '#') {
                if(expMainCount(new, &newl_ind)) return 1;
                oldl_ind++;
            }
            else if(orig[oldl_ind] == '?') {
                if(expLastExitS(new, &newl_ind)) return 1;
                oldl_ind++;
            }
            else
            {
                new[newl_ind] = orig[oldl_ind - 1];
                newl_ind++;
            }
        }
        else if(orig[oldl_ind] == '*')
        {
            if(orig[oldl_ind-1] == ' ' || orig[oldl_ind-1] == '"' || oldl_ind == 0)
            {
                if(orig[oldl_ind+1] == ' ' || orig[oldl_ind+1] == '"' || orig[oldl_ind+1] == 0)
                {
                    if(expWildCard(orig, new, &oldl_ind, &newl_ind, 0)) return 1;
                }
                else
                {
                    if(expWildCard(orig, new, &oldl_ind, &newl_ind, 1)) return 1;
                }
            }
            else if(orig[oldl_ind-1] == '\\')
            {
                new[newl_ind-1] = '*';
                oldl_ind++;
            }
            else
            {
                /*new[newl_ind] = '*';
                newl_ind++;
                oldl_ind++;*/
                if(expLiteralChars(orig, new, &oldl_ind, &newl_ind, &insideQuoteFlag)) return 1;
            }
        }
        else if(orig[oldl_ind] == '#' && !insideQuoteFlag) break;
        else if(orig[oldl_ind] == '~' && orig[oldl_ind-1] == ' ')
        {
            if(expHomeDir(orig, new, &oldl_ind, &newl_ind)) return 1;
        }
        else
        {
            /*if(orig[oldl_ind] == '"') insideQuoteFlag = !insideQuoteFlag;
            new[newl_ind] = orig[oldl_ind];
            newl_ind++;
            oldl_ind++;*/
            if(expLiteralChars(orig, new, &oldl_ind, &newl_ind, &insideQuoteFlag)) return 1;
        }
    }
    new[newl_ind] = 0;
    return 0;
}