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alsh.c
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alsh.c
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#ifdef __clang__
#pragma clang diagnostic ignored "-Wformat-nonliteral"
#endif
#ifdef __GNUC__
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#endif
#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <unistd.h>
#include "isocline/include/isocline.h"
#include "utils/charlist.h"
#include "utils/doublelist.h"
#include "utils/ealloc.h"
#include "utils/mathparser.h"
#include "utils/stringhashmap.h"
#include "utils/stringlinkedlist.h"
#include "utils/utils.h"
#define BACKGROUND_CHAR '&'
#define COMMAND_BUFFER_SIZE 4096
#define COMMENT_CHAR '#'
#define CWD_BUFFER_SIZE 4096
#define EXIT_COMMAND "exit"
#define HISTORY_COMMAND "history"
#define HISTORY_FILE_NAME ".alsh_history"
#define SHELL_NAME "alsh"
#define STARTING_HISTORY_CAPACITY 25
#define TEST_COMMAND "chk"
#define USERNAME_MAX_LENGTH 32
#define VARIABLE_PREFIX '$'
#define MATH_PARSER_ERR_MSG(status) MathParser_printErrMsg(status, SHELL_NAME)
static StringHashMap *aliases; //Stores command aliases
static StringLinkedList *bgCmdDoneMessages; //Stores background command complete messages
static char cwd[CWD_BUFFER_SIZE]; //Current working directory
static char *executablePath; //Path to where the current alsh shell executable is
static bool isBackgroundCmd = false; //Did the user run a command in the background?
static int numBackgroundCmds = 0; //Number of background commands running
static struct passwd *pwd; //User info
static bool testCmdNotExist = false; //Does the '[' command exist?
static bool testCmdNotExistIsSet = false; //Is testCmdNotExist set yet?
static StringHashMap *variables; //Stores user-defined variables
extern char **environ;
char* getHomeDirectory(void) {
return pwd != NULL ? pwd->pw_dir : getenv("HOME");
}
bool isInHomeDirectory(void) {
char *cwdPtr = cwd;
char *homeDirPtr = getHomeDirectory();
while (*homeDirPtr) {
if (*cwdPtr++ != *homeDirPtr++) {
return false;
}
}
return true;
}
bool isRootUser(void) {
return getuid() == 0;
}
typedef struct History {
char **elements;
int count;
int capacity;
} History;
History history;
void clearHistoryElements(void) {
for (int i = 0; i < history.count; i++) {
free(history.elements[i]);
}
history.count = 0;
}
static bool sigintReceived = false;
static bool sigchldReceived = false;
static int numSigchldBackground = 0;
void sigchldHandler(int sig) {
(void) sig;
if (sigintReceived) return;
sigchldReceived = true;
if (isBackgroundCmd) {
if (numBackgroundCmds > 0) {
numSigchldBackground++;
pid_t cid = wait(NULL);
size_t templateStrLen = strlen("[%d]+ Done with pid %d");
size_t numSigchldBackgroundLen = (size_t) numDigits(numSigchldBackground);
size_t cidLen = (size_t) numDigits(cid);
char *buffer = emalloc(sizeof(char) * (templateStrLen + numSigchldBackgroundLen + cidLen));
sprintf(buffer, "[%d]+ Done with pid %d", numSigchldBackground, cid);
StringLinkedList_append(bgCmdDoneMessages, buffer, true);
numBackgroundCmds--;
}
if (numBackgroundCmds == 0) {
isBackgroundCmd = false;
numSigchldBackground = 0;
}
}
}
void sigintHandler(int sig) {
(void) sig;
sigintReceived = true;
if (numBackgroundCmds > 0) {
while (wait(NULL) > 0) {
numBackgroundCmds--;
}
} else {
(void) wait(NULL);
}
}
/**
* If any background command complete message exists in bgCmdDoneMessages,
* print all of them to stderr and pop the nodes containing the messages
* This will also remove all nodes from bgCmdDoneMessages as a result
*/
void printBgCmdDoneMessageIfExists(void) {
if (bgCmdDoneMessages != NULL) {
while (bgCmdDoneMessages->head != NULL) {
fprintf(stderr, "%s\n", bgCmdDoneMessages->head->str);
StringLinkedList_removeIndexAndFreeNode(bgCmdDoneMessages, 0);
}
}
}
/**
* Splits a string from the first occurrence of delim and returns a StringLinkedList
* pointer that refers to the first node of the StringLinkedList
* Remember to free() the returned StringLinkedList
*/
StringLinkedList* split(char *str, char *delim, int *status) {
StringLinkedList *tokens = StringLinkedList_create();
CharList *strList = CharList_create();
size_t delimLen = strlen(delim);
char *tempStr = str;
bool inSingleQuote = false;
bool inDoubleQuote = false;
int parenthesesNestLevel = 0;
while (*tempStr) {
if (!inDoubleQuote && parenthesesNestLevel == 0 && *tempStr == '\'') {
inSingleQuote = !inSingleQuote;
} else if (!inSingleQuote && parenthesesNestLevel == 0 && *tempStr == '"') {
inDoubleQuote = !inDoubleQuote;
} else if (!inDoubleQuote && !inSingleQuote && (*tempStr == '(' || *tempStr == ')')) {
parenthesesNestLevel += *tempStr == '(' ? 1 : -1;
if (parenthesesNestLevel < 0) {
SET_FUNCTION_STATUS(status, -1);
fprintf(stderr, "%s: Unexpected closing parentheses\n", SHELL_NAME);
StringLinkedList_free(tokens);
CharList_free(strList);
StringLinkedList *emptyTokens = StringLinkedList_create();
return emptyTokens;
}
} else if (
!inSingleQuote &&
!inDoubleQuote &&
parenthesesNestLevel == 0 &&
strstr(tempStr, delim) == tempStr
) {
*tempStr = '\0';
tempStr = str;
while (*tempStr) {
if (!inDoubleQuote && parenthesesNestLevel == 0 && *tempStr == '\'') {
inSingleQuote = !inSingleQuote;
} else if (!inSingleQuote && parenthesesNestLevel == 0 && *tempStr == '"') {
inDoubleQuote = !inDoubleQuote;
} else if (!inDoubleQuote && !inSingleQuote && (*tempStr == '(' || *tempStr == ')')) {
parenthesesNestLevel += *tempStr == '(' ? 1 : -1;
if (parenthesesNestLevel < 0) {
SET_FUNCTION_STATUS(status, -1);
fprintf(stderr, "%s: Unexpected closing parentheses\n", SHELL_NAME);
StringLinkedList_free(tokens);
CharList_free(strList);
StringLinkedList *emptyTokens = StringLinkedList_create();
return emptyTokens;
}
}
switch (*tempStr) {
case '"':
if (inSingleQuote || parenthesesNestLevel > 0) {
CharList_add(strList, *tempStr);
}
break;
case '\'':
if (inDoubleQuote || parenthesesNestLevel > 0) {
CharList_add(strList, *tempStr);
}
break;
default:
CharList_add(strList, *tempStr);
break;
}
tempStr++;
}
char *strListCopy = CharList_toStr(strList);
StringLinkedList_append(tokens, strListCopy, true);
CharList_clear(strList);
str = tempStr;
if (*delim == ' ' && !delim[1]) {
do {
str++;
} while (*str == ' ');
} else {
str += delimLen;
}
tempStr = str - 1;
}
tempStr++;
}
if (inSingleQuote || inDoubleQuote || parenthesesNestLevel != 0) {
SET_FUNCTION_STATUS(status, -1);
if (parenthesesNestLevel > 0) {
fprintf(stderr, "%s: Missing closing parentheses\n", SHELL_NAME);
} else if (parenthesesNestLevel < 0) {
fprintf(stderr, "%s: Unexpected closing parentheses\n", SHELL_NAME);
} else {
fprintf(stderr, "%s: Missing closing quote\n", SHELL_NAME);
}
StringLinkedList_free(tokens);
CharList_free(strList);
StringLinkedList *emptyTokens = StringLinkedList_create();
return emptyTokens;
}
tempStr = str;
while (*tempStr) {
if (!inDoubleQuote && parenthesesNestLevel == 0 && *tempStr == '\'') {
inSingleQuote = !inSingleQuote;
} else if (!inSingleQuote && parenthesesNestLevel == 0 && *tempStr == '"') {
inDoubleQuote = !inDoubleQuote;
} else if (!inDoubleQuote && !inSingleQuote && (*tempStr == '(' || *tempStr == ')')) {
parenthesesNestLevel += *tempStr == '(' ? 1 : -1;
if (parenthesesNestLevel < 0) {
SET_FUNCTION_STATUS(status, -1);
fprintf(stderr, "%s: Unexpected closing parentheses\n", SHELL_NAME);
StringLinkedList_free(tokens);
CharList_free(strList);
StringLinkedList *emptyTokens = StringLinkedList_create();
return emptyTokens;
}
}
switch (*tempStr) {
case '"':
if (inSingleQuote || parenthesesNestLevel > 0) {
CharList_add(strList, *tempStr);
}
break;
case '\'':
if (inDoubleQuote || parenthesesNestLevel > 0) {
CharList_add(strList, *tempStr);
}
break;
default:
CharList_add(strList, *tempStr);
break;
}
tempStr++;
}
char *strListCopy = CharList_toStr(strList);
StringLinkedList_append(tokens, strListCopy, true);
CharList_free(strList);
return tokens;
}
/**
* Executes a function specified by the processLine function pointer
* on each line from the file referred to by fp
*
* Returns the status of the last command executed from the file
*/
int processFile(char *cmd, FILE *fp, int (*processLine)(char*), bool closefp) {
int status = 0;
while (fgets(cmd, COMMAND_BUFFER_SIZE, fp) != NULL) {
removeNewlineIfExists(cmd);
bool trimSuccess = trimWhitespaceFromEnds(cmd);
if (*cmd && *cmd != COMMENT_CHAR && trimSuccess) {
status = processLine(cmd);
}
}
if (closefp) fclose(fp);
return status;
}
int* handleRedirectStdout(char *cmd) {
char *stdoutRedirectChr = NULL;
int *status;
if (strchr(cmd, '>') != NULL) {
bool inSingleQuote = false;
bool inDoubleQuote = false;
bool inParentheses = false;
for (char *cmdPtr = cmd; *cmdPtr; cmdPtr++) {
if (*cmdPtr == '\'') {
if (!inDoubleQuote && !inParentheses) {
inSingleQuote = !inSingleQuote;
}
} else if (*cmdPtr == '"') {
if (!inSingleQuote && !inParentheses) {
inDoubleQuote = !inDoubleQuote;
}
} else if (*cmdPtr == '(' || *cmdPtr == ')') {
if (!inSingleQuote && !inDoubleQuote) {
inParentheses = *cmdPtr == '(';
}
}
if (*cmdPtr == '>' && !inSingleQuote && !inDoubleQuote && !inParentheses) {
stdoutRedirectChr = cmdPtr;
break;
}
}
if (stdoutRedirectChr == NULL) {
status = ecalloc(1, sizeof(int));
return status;
}
char *fileName = stdoutRedirectChr + 1;
const char *fopenMode = "w";
while (*fileName == ' ' || *fileName == '>') {
if (*fileName == '>') fopenMode = "a";
fileName++;
}
trimWhitespaceFromEnds(fileName);
if (!*fileName) {
fprintf(stderr, "%s: %s: Missing file name\n", SHELL_NAME, *fopenMode == 'a' ? ">>" : ">");
status = emalloc(sizeof(int));
*status = -1;
} else {
int oldStdout = dup(STDOUT_FILENO);
status = emalloc(sizeof(int) * 3);
*status = 1;
status[1] = oldStdout;
if (*cmd != '>' && isdigit(stdoutRedirectChr[-1])) {
char *digit = stdoutRedirectChr - 1;
do {
digit--;
} while (isdigit(*digit));
if (*digit == ' ') {
digit = stdoutRedirectChr - 1;
int fileDescriptor = 0;
int factor = 1;
do {
fileDescriptor += (*digit - '0') * factor;
factor *= 10;
} while (isdigit(*--digit));
status[2] = fileDescriptor;
} else {
status[2] = STDOUT_FILENO;
}
} else {
status[2] = STDOUT_FILENO;
}
FILE *fp = fopen(fileName, fopenMode);
dup2(fileno(fp), status[2]);
fclose(fp);
}
} else {
status = ecalloc(1, sizeof(int));
}
return status;
}
int* handleRedirectStdin(char *cmd) {
char *stdinRedirectChr = NULL;
int *status;
if (strchr(cmd, '<') != NULL) {
bool inSingleQuote = false;
bool inDoubleQuote = false;
bool inParentheses = false;
for (char *cmdPtr = cmd; *cmdPtr; cmdPtr++) {
if (*cmdPtr == '\'') {
if (!inDoubleQuote && !inParentheses) {
inSingleQuote = !inSingleQuote;
}
} else if (*cmdPtr == '"') {
if (!inSingleQuote && !inParentheses) {
inDoubleQuote = !inDoubleQuote;
}
} else if (*cmdPtr == '(' || *cmdPtr == ')') {
if (!inSingleQuote && !inDoubleQuote) {
inParentheses = *cmdPtr == '(';
}
}
if (*cmdPtr == '<' && !inSingleQuote && !inDoubleQuote && !inParentheses) {
stdinRedirectChr = cmdPtr;
break;
}
}
if (stdinRedirectChr == NULL) {
status = ecalloc(1, sizeof(int));
return status;
}
char *tempCmd = strdup(cmd);
char *fileName = strchr(tempCmd, '<') + 1;
while (*fileName == ' ') {
fileName++;
}
trimWhitespaceFromEnds(fileName);
char *stdoutRedirectChr = strchr(fileName, '>');
if (stdoutRedirectChr != NULL) {
do {
stdoutRedirectChr--;
} while (isdigit(*stdoutRedirectChr));
//If n is the file descriptor to redirect to, parse "a < bn>c" as "a < bn > c"
if (*stdoutRedirectChr == ' ') {
do {
stdoutRedirectChr--;
} while (*stdoutRedirectChr == ' ');
stdoutRedirectChr++;
} else {
do {
stdoutRedirectChr++;
} while (isdigit(*stdoutRedirectChr));
}
*stdoutRedirectChr = '\0';
}
FILE *fp = fopen(fileName, "r");
if (fp == NULL) {
fprintf(stderr, "%s: %s: No such file or directory\n", SHELL_NAME, fileName);
status = emalloc(sizeof(int));
*status = -1;
} else {
int oldStdin = dup(STDIN_FILENO);
dup2(fileno(fp), STDIN_FILENO);
fclose(fp);
status = emalloc(sizeof(int) * 2);
*status = 1;
status[1] = oldStdin;
}
free(tempCmd);
} else {
status = ecalloc(1, sizeof(int));
}
return status;
}
int processCommand(char *cmd);
char* processMathExpressions(char *cmd, bool *seenOtherChr);
char* processVariables(char *cmd, bool *hasUndefinedVars);
int executeCommand(char *cmd, bool waitForCommand) {
char *processVarCmd = NULL;
if (cmd == NULL || !*cmd || (processVarCmd = processVariables(cmd, NULL)) == NULL) {
return 1;
}
char *originalCmd = cmd;
bool processedVars = processVarCmd != originalCmd;
if (processedVars) {
trimWhitespaceFromEnds(processVarCmd);
cmd = processVarCmd;
}
int *stdinStatus = handleRedirectStdin(cmd);
if (*stdinStatus == -1) {
free(stdinStatus);
if (processedVars) free(processVarCmd);
return 1;
}
int *stdoutStatus = handleRedirectStdout(cmd);
if (*stdoutStatus == -1) {
free(stdinStatus);
free(stdoutStatus);
if (processedVars) free(processVarCmd);
return 1;
}
int exitStatus = 0;
CharList *tempCmd = CharList_create();
bool inSingleQuote = false;
bool inDoubleQuote = false;
bool inParentheses = false;
char *cmdPtr = cmd;
int cmdIndex = 0;
while (*cmdPtr) {
switch (*cmdPtr) {
case '\'': {
if (!inDoubleQuote && !inParentheses) {
inSingleQuote = !inSingleQuote;
}
break;
}
case '"': {
if (!inSingleQuote && !inParentheses) {
inDoubleQuote = !inDoubleQuote;
}
break;
}
case '(':
case ')': {
if (!inSingleQuote && !inDoubleQuote) {
inParentheses = !inParentheses;
}
break;
}
}
switch (*cmdPtr) {
case '<':
case '>': {
if (inSingleQuote || inDoubleQuote || inParentheses) {
CharList_add(tempCmd, *cmdPtr++);
break;
}
char *cmdPtrLeft = cmdPtr - 1;
char *cmdPtrRight = cmdPtr + 1;
bool noSpaceOnLeft = *cmdPtrLeft != ' ' && *cmdPtrLeft != '>';
bool noSpaceOnRight = *cmdPtrRight != ' ' && *cmdPtrRight != '>';
//Avoid ub if cmdPtr is at the beginning of the string
if (cmdIndex > 0 && (noSpaceOnLeft || noSpaceOnRight)) {
if (noSpaceOnLeft
&& (
!isdigit(*cmdPtrLeft)
|| (
cmdIndex > 1
&& *(cmdPtrLeft - 1) != ' '
)
)
) {
CharList_add(tempCmd, ' ');
}
CharList_add(tempCmd, *cmdPtr++);
if (*++cmdPtrLeft == '>' && *cmdPtr == '>') {
CharList_add(tempCmd, *cmdPtr++);
}
//Do not put this line in any if statement so that a space is
//always added to the right of the rightmost redirection character
CharList_add(tempCmd, ' ');
} else {
CharList_add(tempCmd, *cmdPtr++);
}
break;
}
default:
CharList_add(tempCmd, *cmdPtr++);
break;
}
cmdIndex++;
}
int tokensStatus = 1;
StringLinkedList *tokens = split(tempCmd->data, " ", &tokensStatus);
if (tokens->size == 0) {
if (*stdinStatus) {
dup2(stdinStatus[1], STDIN_FILENO);
close(stdinStatus[1]);
}
if (*stdoutStatus) {
dup2(stdoutStatus[1], stdoutStatus[2]);
close(stdoutStatus[1]);
}
free(stdinStatus);
free(stdoutStatus);
CharList_free(tempCmd);
StringLinkedList_free(tokens);
if (processedVars) free(processVarCmd);
return tokensStatus;
}
bool isBuiltInCommand = false;
int tempNodeIndex = 0;
for (StringNode *temp = tokens->head; temp != NULL;) {
char *strToRemove = temp->str;
size_t strToRemoveLen = strlen(strToRemove);
char lastChr = strToRemove[strToRemoveLen - 1];
if (lastChr == '<' || lastChr == '>') {
temp = temp->next;
if (temp != NULL) {
temp = temp->next;
StringLinkedList_removeIndexAndFreeNode(tokens, tempNodeIndex);
}
StringLinkedList_removeIndexAndFreeNode(tokens, tempNodeIndex);
} else if (temp->strMustBeFreed) {
bool seenOtherChr = false;
char *finalStr = processMathExpressions(strToRemove, &seenOtherChr);
if (finalStr == NULL) {
if (*stdinStatus) {
dup2(stdinStatus[1], STDIN_FILENO);
close(stdinStatus[1]);
}
if (*stdoutStatus) {
dup2(stdoutStatus[1], stdoutStatus[2]);
close(stdoutStatus[1]);
}
free(stdinStatus);
free(stdoutStatus);
CharList_free(tempCmd);
StringLinkedList_free(tokens);
if (processedVars) free(processVarCmd);
return 1;
}
if (finalStr != strToRemove) {
free(temp->str);
temp->str = finalStr;
temp = temp->next;
if (temp == NULL && tempNodeIndex == 0 && !seenOtherChr) {
printf("%s\n", finalStr);
isBuiltInCommand = true;
}
} else {
temp = temp->next;
}
tempNodeIndex++;
} else {
temp = temp->next;
tempNodeIndex++;
}
}
StringNode *head = tokens->head;
if (aliases != NULL && head != NULL) {
char *alias = StringHashMap_get(aliases, head->str);
if (alias != NULL && strcmp(alias, head->str) != 0) {
if (!*alias) {
if (*stdinStatus) {
dup2(stdinStatus[1], STDIN_FILENO);
close(stdinStatus[1]);
}
if (*stdoutStatus) {
dup2(stdoutStatus[1], stdoutStatus[2]);
close(stdoutStatus[1]);
}
free(stdinStatus);
free(stdoutStatus);
CharList_free(tempCmd);
StringLinkedList_free(tokens);
if (processedVars) free(processVarCmd);
return 1;
}
if (strchr(alias, ' ') != NULL) { //Alias value has space
char *aliasDup = strdup(alias);
StringLinkedList *aliasTokens = split(aliasDup, " ", NULL);
char **aliasTokensArr = StringLinkedList_toArray(aliasTokens);
StringLinkedList_removeIndexAndFreeNode(tokens, 0);
for (int i = StringLinkedList_size(aliasTokens) - 1; i >= 0; i--) {
StringLinkedList_prepend(tokens, strdup(aliasTokensArr[i]), true);
}
free(aliasTokensArr);
free(aliasDup);
StringLinkedList_free(aliasTokens);
head = tokens->head;
} else {
if (head->strMustBeFreed) {
free(head->str);
}
head->str = alias;
bool *mustBeFreed = StringHashMap_getMustBeFreed(aliases, head->str);
if (mustBeFreed != NULL) {
head->strMustBeFreed = mustBeFreed[1];
free(mustBeFreed);
} else {
//Should not happen
head->str = strdup(alias);
}
}
}
}
bool isExport = false;
if (head == NULL || strcmp(head->str, "false") == 0) {
isBuiltInCommand = true;
exitStatus = 1;
} else if (strcmp(head->str, "true") == 0) {
isBuiltInCommand = true;
exitStatus = 0;
} else if (strcmp(head->str, "cd") == 0) {
isBuiltInCommand = true;
StringNode *argNode = head->next;
char *arg = argNode != NULL ? argNode->str : NULL;
if (arg == NULL) { //No argument, change to home directory
if (chdir(getHomeDirectory()) != 0) {
//Should not happen
fprintf(stderr, "%s: cd: Failed to change to home directory\n", SHELL_NAME);
exitStatus = 1;
}
} else if (strcmp(arg, "..") == 0) { //Go up one directory
char *lastSlashPos = strrchr(cwd, '/');
*(lastSlashPos + 1) = '\0';
if (chdir(cwd) != 0) {
//Should not happen
switch (errno) {
case EACCES:
fprintf(stderr, "%s: cd: %s: Permission denied\n", SHELL_NAME, arg);
break;
default:
fprintf(stderr, "%s: cd: Failed to change to parent directory\n", SHELL_NAME);
break;
}
exitStatus = 1;
}
} else if (chdir(arg) != 0) { //Change to specified directory
char *err;
switch (errno) {
case EACCES:
err = "Permission denied";
break;
case ENOENT:
err = "No such file or directory";
break;
default:
err = "Failed to change to directory";
break;
}
fprintf(stderr, "%s: cd: %s: %s\n", SHELL_NAME, arg, err);
exitStatus = 1;
}
} else if (strcmp(head->str, "source") == 0) {
isBuiltInCommand = true;
StringNode *fileNameNode = head->next;
if (fileNameNode == NULL) {
fprintf(stderr, "%s: source: filename argument required\n", SHELL_NAME);
exitStatus = 1;
} else {
char *fileName = fileNameNode->str;
FILE *fp = fopen(fileName, "r");
if (fp == NULL) {
fprintf(stderr, "%s: %s: No such file or directory\n", SHELL_NAME, fileName);
exitStatus = 1;
} else {
char *cmdBuf = emalloc(sizeof(char) * COMMAND_BUFFER_SIZE);
exitStatus = processFile(cmdBuf, fp, processCommand, true);
free(cmdBuf);
}
}
} else if ((isExport = strcmp(head->str, "export") == 0) || strcmp(head->str, "let") == 0) {
isBuiltInCommand = true;
if (head->next == NULL) {
if (isExport) {
char **environPtr = environ;
while (*environPtr) {
char *envStr = *environPtr++;
printf("export ");
while (*envStr && *envStr != '=') {
putchar(*envStr++);
}
putchar('=');
putchar('\'');
while (*++envStr) {
putchar(*envStr);
}
putchar('\'');
putchar('\n');
}
} else if (variables != NULL) {
char ***keysVals = StringHashMap_entries(variables);
int keysValsSize = StringHashMap_size(variables);
for (int i = 0; i < keysValsSize; i++) {
printf("let %s=\"%s\"\n", keysVals[i][0], keysVals[i][1]);
free(keysVals[i]);
}
free(keysVals);
}
} else if (!isExport && variables == NULL) {
variables = StringHashMap_create();
}
for (StringNode *argNode = head->next; argNode != NULL; argNode = argNode->next) {
char *argStr = argNode->str;
char *equalsSign = strchr(argStr, '=');
if (equalsSign != NULL) {
if (argStr[0] == '=') {
fprintf(stderr, "%s: %s: unexpected token '='", SHELL_NAME, isExport ? "export" : "let");
exitStatus = 1;
continue;
}
StringLinkedList *varList = split(argStr, "=", NULL);
char *varKey = varList->head->str;
char *varVal = varList->head->next->str;
bool replacingLetVal = variables != NULL && StringHashMap_get(variables, varKey) != NULL;
if (isExport) {
setenv(varKey, varVal, true);
if (replacingLetVal) {
StringHashMap_remove(variables, varKey);
}
} else {
char *varKeyDup = strdup(varKey);
char *varValDup = strdup(varVal);
bool replacingExportVal = getenv(varKey) != NULL;
StringHashMap_put(variables, varKeyDup, true, varValDup, true);
if (replacingLetVal) {
free(varKeyDup);
}
if (replacingExportVal) {
unsetenv(varKey);
}
}
StringLinkedList_free(varList);
} else if (isExport && variables != NULL) {
char *letVal = StringHashMap_get(variables, argStr);
if (letVal != NULL) {
setenv(argStr, letVal, true);
StringHashMap_remove(variables, argStr);
}
}
}
} else if (strcmp(head->str, TEST_COMMAND) == 0) {
isBuiltInCommand = true;
double first = 0;
char *testCond = NULL;
double second = 0;
char *validTestOps[] = {"eq", "ne", "lt", "le", "gt", "ge"};
size_t validTestOpsLen = sizeof(validTestOps) / sizeof(*validTestOps);
StringNode *nextNode = head->next;
bool testError = false;
const int numArgs = 3;
for (int i = 0; i < numArgs; i++) {
char *errorStr = NULL;
switch (i) {
case 0: {
if (nextNode == NULL) {
fprintf(stderr, "%s: %s: Missing first value\n", SHELL_NAME, TEST_COMMAND);
testError = true;
break;
}
first = strtod(nextNode->str, &errorStr);
if (*errorStr) {
fprintf(stderr, "%s: %s: First value is not a number\n", SHELL_NAME, TEST_COMMAND);
testError = true;
break;
}
break;
}
case 1: {
if (nextNode == NULL) {
fprintf(stderr, "%s: %s: Missing test condition. ", SHELL_NAME, TEST_COMMAND);
fprintf(stderr, "Valid conditions include: ");
for (size_t j = 0; j < validTestOpsLen; j++) {
fprintf(stderr, "%s", validTestOps[j]);
if (j < validTestOpsLen - 1) {
fprintf(stderr, ", ");
}
}
fprintf(stderr, "\n");
testError = true;
break;
}
testCond = nextNode->str;
if (!strArrContains(validTestOps, testCond + (*testCond == '-'), validTestOpsLen)) {
fprintf(stderr, "%s: %s: Invalid test condition. ", SHELL_NAME, TEST_COMMAND);
fprintf(stderr, "Valid conditions include: ");
for (size_t j = 0; j < validTestOpsLen; j++) {
fprintf(stderr, "%s", validTestOps[j]);
if (j < validTestOpsLen - 1) {
fprintf(stderr, ", ");
}
}
fprintf(stderr, "\n");
testError = true;
break;
}
break;
}
case 2: {
if (nextNode == NULL) {
fprintf(stderr, "%s: %s: Missing second value\n", SHELL_NAME, TEST_COMMAND);
testError = true;
break;
}
second = strtod(nextNode->str, &errorStr);
if (*errorStr) {
fprintf(stderr, "%s: %s: Second value is not a number\n", SHELL_NAME, TEST_COMMAND);
testError = true;
break;
}
break;
}
}
if (testError) break;
nextNode = nextNode->next;
}
if (!testError) {
bool containsDash = false;
if (*testCond == '-') {
containsDash = true;
testCond++;
}
//0 denotes success, 1 denotes failure
if (strcmp(testCond, validTestOps[0]) == 0) {
exitStatus = !(fabs(first - second) < EPSILON);
} else if (strcmp(testCond, validTestOps[1]) == 0) {
exitStatus = !(fabs(first - second) >= EPSILON);
} else if (strcmp(testCond, validTestOps[2]) == 0) {
exitStatus = !(first < second);
} else if (strcmp(testCond, validTestOps[3]) == 0) {
exitStatus = !(first <= second);
} else if (strcmp(testCond, validTestOps[4]) == 0) {
exitStatus = !(first > second);
} else {
exitStatus = !(first >= second);
}
if (containsDash) testCond--;
} else {
exitStatus = 1;
}
} else if (strcmp(head->str, "alias") == 0) {
isBuiltInCommand = true;
if (head->next == NULL) {
if (aliases != NULL) {
char ***keysVals = StringHashMap_entries(aliases);
int keysValsSize = StringHashMap_size(aliases);
for (int i = 0; i < keysValsSize; i++) {
printf("alias %s=\"%s\"\n", keysVals[i][0], keysVals[i][1]);
free(keysVals[i]);
}
free(keysVals);
}
} else if (aliases == NULL) {
aliases = StringHashMap_create();
}
for (StringNode *argNode = head->next; argNode != NULL; argNode = argNode->next) {
char *argStr = argNode->str;
char *equalsSign = strchr(argStr, '=');
if (equalsSign != NULL) {
if (argStr[0] == '=') {
fprintf(stderr, "%s: alias: %s: not found\n", SHELL_NAME, argStr);
exitStatus = 1;
continue;
}
StringLinkedList *aliasList = split(argStr, "=", NULL);
char *aliasKey = aliasList->head->str;
char *aliasVal = aliasList->head->next->str;
char *aliasKeyDup = strdup(aliasKey);
char *aliasValDup = strdup(aliasVal);
bool replacingVal = StringHashMap_get(aliases, aliasKey) != NULL;
StringHashMap_put(aliases, aliasKeyDup, true, aliasValDup, true);
if (replacingVal) {
free(aliasKeyDup);
}
StringLinkedList_free(aliasList);
} else {
char *value = StringHashMap_get(aliases, argStr);
if (value != NULL) {
printf("alias %s=\"%s\"\n", argStr, value);
} else {
fprintf(stderr, "%s: alias: %s: not found\n", SHELL_NAME, argStr);
exitStatus = 1;
}
}
}
} else if (strcmp(head->str, "exec") == 0) {
StringNode *argNode = head->next;
StringLinkedList_removeIndexAndFreeNode(tokens, 0);
char *command;
if (argNode != NULL) {
command = argNode->str;
} else {
StringLinkedList_append(tokens, executablePath, false);
command = executablePath;
}
StringLinkedList_append(tokens, NULL, false);
char **tokensArr = StringLinkedList_toArray(tokens);