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/*
* Copyright (c) 2004 by David I. Bell
* Permission is granted to use, distribute, or modify this source,
* provided that this copyright notice remains intact.
*
* Stand-alone shell for system maintainance for Linux.
* This program should NOT be built using shared libraries.
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <errno.h>
#include "sash.h"
static const char * const version = "3.7";
/*
* The special maximum argument value which means that there is
* no limit to the number of arguments on the command line.
*/
#define INFINITE_ARGS 0x7fffffff
/*
* One entry of the command table.
*/
typedef struct
{
const char * name;
void (*func)(int argc, const char ** argv);
int minArgs;
int maxArgs;
const char * description;
const char * usage;
} CommandEntry;
/*
* The table of built-in commands.
* This is terminated wih an entry containing NULL values.
*/
static const CommandEntry commandEntryTable[] =
{
{
"alias", do_alias, 1, INFINITE_ARGS,
"Define a command alias",
"[name [command]]"
},
{
"aliasall", do_aliasall, 1, 1,
"Define aliases for all of the build-in commands",
""
},
{
"-ar", do_ar, 3, INFINITE_ARGS,
"Extract or list files from an AR file",
"[txp]v arFileName fileName ..."
},
{
"cd", do_cd, 1, 2,
"Change current directory",
"[dirName]"
},
#if HAVE_LINUX_ATTR
{
"-chattr", do_chattr, 3, INFINITE_ARGS,
"Change ext2 file attributes",
"[+i] [-i] [+a] [-a] fileName ..."
},
#endif
{
"-chgrp", do_chgrp, 3, INFINITE_ARGS,
"Change the group id of some files",
"gid fileName ..."
},
{
"-chmod", do_chmod, 3, INFINITE_ARGS,
"Change the protection of some files",
"mode fileName ..."
},
{
"-chown", do_chown, 3, INFINITE_ARGS,
"Change the owner id of some files",
"uid fileName ..."
},
{
"-cmp", do_cmp, 3, 3,
"Compare two files for equality",
"fileName1 fileName2"
},
{
"-cp", do_cp, 3, INFINITE_ARGS,
"Copy files",
"srcName ... destName"
},
{
"-dd", do_dd, 3, INFINITE_ARGS,
"Copy data between two files",
"if=name of=name [bs=n] [count=n] [skip=n] [seek=n]"
},
{
"-echo", do_echo, 1, INFINITE_ARGS,
"Echo the arguments",
"[args] ..."
},
{
"-ed", do_ed, 1, 2,
"Edit a fileName using simple line mode commands",
"[fileName]"
},
{
"exec", do_exec, 2, INFINITE_ARGS,
"Execute another program in place of this sash process",
"fileName [args]"
},
{
"exit", do_exit, 1, 2,
"Exit from sash",
"[exit value]"
},
{
"-file", do_file, 1, INFINITE_ARGS,
"Describe information about files",
"fileName ..."
},
{
"-find", do_find, 2, INFINITE_ARGS,
"Find files in a directory tree meeting some conditions",
"dirName [-xdev] [-type chars] [-name pattern] [-size minSize]"
},
{
"-grep", do_grep, 3, INFINITE_ARGS,
"Look for lines containing a word in some files",
"[-in] word fileName ..."
},
#if HAVE_GZIP
{
"-gunzip", do_gunzip, 2, INFINITE_ARGS,
"Uncompress files which were saved in GZIP or compress format",
"fileName ... [-o outputPath]"
},
{
"-gzip", do_gzip, 2, INFINITE_ARGS,
"Compress files into GZIP format",
"fileName ... [-o outputPath]"
},
#endif
{
"help", do_help, 1, 2,
"Print help about a command",
"[word]"
},
{
"-kill", do_kill, 2, INFINITE_ARGS,
"Send a signal to the specified process",
"[-sig] pid ..."
},
{
"-ln", do_ln, 3, INFINITE_ARGS,
"Link one fileName to another",
"[-s] srcName ... destName"
},
{
"-ls", do_ls, 1, INFINITE_ARGS,
"List information about files or directories",
"[-lidFC] fileName ..."
},
#if HAVE_LINUX_ATTR
{
"-lsattr", do_lsattr, 2, INFINITE_ARGS,
"List ext2 file attributes",
"fileName ..."
},
#endif
{
"-mkdir", do_mkdir, 2, INFINITE_ARGS,
"Create a directory",
"dirName ..."
},
{
"-mknod", do_mknod, 5, 5,
"Create a special type of file",
"fileName type major minor"
},
{
"-more", do_more, 2, INFINITE_ARGS,
"Type file contents page by page",
"fileName ..."
},
{
"-mount", do_mount, 3, INFINITE_ARGS,
"Mount or remount a filesystem on a directory",
#if HAVE_LINUX_MOUNT
"[-t type] [-r] [-s] [-e] [-m] devName dirName"
#elif HAVE_BSD_MOUNT
"[-t type] [-r] [-s] [-e] devName dirName"
#else
"[-t type] devName dirName"
#endif
},
{
"-mv", do_mv, 3, INFINITE_ARGS,
"Move or rename files",
"srcName ... destName"
},
{
"-printenv", do_printenv, 1, 2,
"Print environment variables",
"[name]"
},
{
"prompt", do_prompt, 2, INFINITE_ARGS,
"Set the prompt string for sash",
"string"
},
{
"-pwd", do_pwd, 1, 1,
"Print the current working directory",
""
},
{
"quit", do_exit, 1, 1,
"Exit from sash",
""
},
{
"-rm", do_rm, 2, INFINITE_ARGS,
"Remove the specified files",
"fileName ..."
},
{
"-rmdir", do_rmdir, 2, INFINITE_ARGS,
"Remove the specified empty directories",
"dirName ..."
},
{
"setenv", do_setenv, 3, 3,
"Set an environment variable value",
"name value"
},
{
"source", do_source, 2, 2,
"Read commands from the specified file",
"fileName"
},
{
"-sum", do_sum, 2, INFINITE_ARGS,
"Calculate checksums of the specified files",
"fileName ..."
},
{
"-sync", do_sync, 1, 1,
"Sync the disks to force cached data to them",
""
},
{
"-tar", do_tar, 2, INFINITE_ARGS,
"Create, extract, or list files from a TAR file",
"[cxtv]f tarFileName fileName ..."
},
{
"-touch", do_touch, 2, INFINITE_ARGS,
"Update times or create the specified files",
"fileName ..."
},
{
"umask", do_umask, 1, 2,
"Set the umask value for file protections",
"[mask]"
},
{
#if HAVE_BSD_MOUNT
"-umount", do_umount, 2, 3,
"Unmount a filesystem",
"[-f] fileName"
#else
"-umount", do_umount, 2, 2,
"Unmount a filesystem",
"fileName"
#endif
},
{
"unalias", do_unalias, 2, 2,
"Remove a command alias",
"name"
},
{
"-where", do_where, 2, 2,
"Type the location of a program",
"program"
},
{
NULL, 0, 0, 0,
NULL,
NULL
}
};
/*
* The definition of an command alias.
*/
typedef struct
{
char * name;
char * value;
} Alias;
/*
* Local data.
*/
static Alias * aliasTable;
static int aliasCount;
static FILE * sourcefiles[MAX_SOURCE];
static int sourceCount;
static BOOL intCrlf = TRUE;
static char * prompt;
/*
* Local procedures.
*/
static void catchInt(int);
static void catchQuit(int);
static int readFile(const char * name);
static int command(const char * cmd);
static BOOL tryBuiltIn(const char * cmd);
static int runCmd(const char * cmd);
static void childProcess(const char * cmd);
static void showPrompt(void);
static void usage(void);
static Alias * findAlias(const char * name);
/*
* Global interrupt flag.
*/
BOOL intFlag;
int
main(int argc, const char ** argv)
{
const char * cp;
const char * singleCommand;
const char * commandFile;
BOOL quietFlag;
BOOL aliasFlag;
BOOL interactiveFlag;
char buf[PATH_LEN];
singleCommand = NULL;
commandFile = NULL;
quietFlag = FALSE;
aliasFlag = FALSE;
interactiveFlag = FALSE;
/*
* Look for options.
*/
argv++;
argc--;
while ((argc > 0) && (**argv == '-'))
{
cp = *argv++ + 1;
argc--;
while (*cp) switch (*cp++)
{
case '-':
/*
* Ignore. This is so that we can be
* run from login.
*/
break;
case 'c':
/*
* Execute specified command.
*/
if ((argc != 1) || singleCommand || interactiveFlag)
usage();
singleCommand = *argv++;
argc--;
break;
case 'f':
/*
* Execute commands from file.
* This is used for sash script files.
* The quiet flag is also set.
*/
if ((argc != 1) || commandFile)
usage();
quietFlag = TRUE;
commandFile = *argv++;
argc--;
break;
case 'i':
/*
* Be an interactive shell
* ..is a no-op, but some contexts require this
* ..interactiveFlag is to avoid -ic as a legacy
*/
if (singleCommand)
usage();
interactiveFlag = TRUE;
break;
case 'p':
/*
* Set the prompt string.
*/
if ((argc <= 0) || (**argv == '-'))
usage();
if (prompt)
free(prompt);
prompt = strdup(*argv++);
argc--;
break;
case 'q':
quietFlag = TRUE;
break;
case 'a':
aliasFlag = TRUE;
break;
case 'h':
case '?':
usage();
break;
default:
fprintf(stderr, "Unknown option -%c\n", cp[-1]);
return 1;
}
}
/*
* No more arguments are allowed.
*/
if (argc > 0)
usage();
/*
* Default our path if it is not set.
*/
if (getenv("PATH") == NULL)
putenv("PATH=/bin:/usr/bin:/sbin:/usr/sbin:/etc");
/*
* If the alias flag is set then define all aliases.
*/
if (aliasFlag)
do_aliasall(0, NULL);
/*
* If we are to execute a single command, then do so and exit.
*/
if (singleCommand)
{
return command(singleCommand);
}
/*
* Print a hello message unless we are told to be silent.
*/
if (!quietFlag && isatty(STDIN))
{
printf("Stand-alone shell (version %s)\n", version);
if (aliasFlag)
printf("Built-in commands are aliased to standard commands\n");
}
signal(SIGINT, catchInt);
signal(SIGQUIT, catchQuit);
/*
* Execute the user's alias file if present.
*/
cp = getenv("HOME");
if (cp)
{
strcpy(buf, cp);
strcat(buf, "/");
strcat(buf, ".aliasrc");
if ((access(buf, 0) == 0) || (errno != ENOENT))
readFile(buf);
}
/*
* Read commands from stdin or from a command file.
*/
return readFile(commandFile);
}
/*
* Read commands from the specified file.
* A null name pointer indicates to read from stdin.
*/
static int
readFile(const char * name)
{
FILE * fp;
int cc;
BOOL ttyFlag;
char buf[CMD_LEN];
int r = 0;
if (sourceCount >= MAX_SOURCE)
{
fprintf(stderr, "Too many source files\n");
return 1;
}
fp = stdin;
if (name)
{
fp = fopen(name, "r");
if (fp == NULL)
{
perror(name);
return 1;
}
}
sourcefiles[sourceCount++] = fp;
ttyFlag = isatty(fileno(fp));
while (TRUE)
{
if (ttyFlag)
showPrompt();
if (intFlag && !ttyFlag && (fp != stdin))
{
fclose(fp);
sourceCount--;
return 1;
}
if (fgets(buf, CMD_LEN - 1, fp) == NULL)
{
if (ferror(fp) && (errno == EINTR))
{
clearerr(fp);
continue;
}
break;
}
cc = strlen(buf);
if (buf[cc - 1] == '\n')
cc--;
while ((cc > 0) && isBlank(buf[cc - 1]))
cc--;
buf[cc] = '\0';
r = command(buf);
}
if (ferror(fp))
{
perror("Reading command line");
if (fp == stdin)
exit(1);
}
clearerr(fp);
if (fp != stdin)
fclose(fp);
sourceCount--;
return r;
}
/*
* Parse and execute one null-terminated command line string.
* This breaks the command line up into words, checks to see if the
* command is an alias, and expands wildcards.
*/
static int
command(const char * cmd)
{
const char * endCmd;
const Alias * alias;
char newCommand[CMD_LEN];
char cmdName[CMD_LEN];
/*
* Rest the interrupt flag and free any memory chunks that
* were allocated by the previous command.
*/
intFlag = FALSE;
freeChunks();
/*
* Skip leading blanks.
*/
while (isBlank(*cmd))
cmd++;
/*
* If the command is empty or is a comment then ignore it.
*/
if ((*cmd == '\0') || (*cmd == '#'))
return 0;
/*
* Look for the end of the command name and then copy the
* command name to a buffer so we can null terminate it.
*/
endCmd = cmd;
while (*endCmd && !isBlank(*endCmd))
endCmd++;
memcpy(cmdName, cmd, endCmd - cmd);
cmdName[endCmd - cmd] = '\0';
/*
* Search for the command name in the alias table.
* If it is found, then replace the command name with
* the alias value, and append the current command
* line arguments to that.
*/
alias = findAlias(cmdName);
if (alias)
{
strcpy(newCommand, alias->value);
strcat(newCommand, endCmd);
cmd = newCommand;
}
/*
* Now look for the command in the builtin table, and execute
* the command if found.
*/
if (tryBuiltIn(cmd))
return 0; /* This is a blatant lie */
/*
* The command is not a built-in, so run the program along
* the PATH list.
*/
return runCmd(cmd);
}
/*
* Try to execute a built-in command.
* Returns TRUE if the command is a built in, whether or not the
* command succeeds. Returns FALSE if this is not a built-in command.
*/
static BOOL
tryBuiltIn(const char * cmd)
{
const char * endCmd;
const CommandEntry * entry;
int argc;
const char ** argv;
char cmdName[CMD_LEN];
/*
* Look for the end of the command name and then copy the
* command name to a buffer so we can null terminate it.
*/
endCmd = cmd;
while (*endCmd && !isBlank(*endCmd))
endCmd++;
memcpy(cmdName, cmd, endCmd - cmd);
cmdName[endCmd - cmd] = '\0';
/*
* Search the command table looking for the command name.
*/
for (entry = commandEntryTable; entry->name != NULL; entry++)
{
if (strcmp(entry->name, cmdName) == 0)
break;
}
/*
* If the command is not a built-in, return indicating that.
*/
if (entry->name == NULL)
return FALSE;
/*
* The command is a built-in.
* Break the command up into arguments and expand wildcards.
*/
if (!makeArgs(cmd, &argc, &argv))
return TRUE;
/*
* Give a usage string if the number of arguments is too large
* or too small.
*/
if ((argc < entry->minArgs) || (argc > entry->maxArgs))
{
fprintf(stderr, "usage: %s %s\n", entry->name, entry->usage);
return TRUE;
}
/*
* Call the built-in function with the argument list.
*/
entry->func(argc, argv);
return TRUE;
}
/*
* Execute the specified command either by forking and executing
* the program ourself, or else by using the shell.
*/
static int
runCmd(const char * cmd)
{
const char * cp;
BOOL magic;
pid_t pid;
int status;
/*
* Check the command for any magic shell characters
* except for quoting.
*/
magic = FALSE;
for (cp = cmd; *cp; cp++)
{
if ((*cp >= 'a') && (*cp <= 'z'))
continue;
if ((*cp >= 'A') && (*cp <= 'Z'))
continue;
if (isDecimal(*cp))
continue;
if (isBlank(*cp))
continue;
if ((*cp == '.') || (*cp == '/') || (*cp == '-') ||
(*cp == '+') || (*cp == '=') || (*cp == '_') ||
(*cp == ':') || (*cp == ',') || (*cp == '\'') ||
(*cp == '"'))
{
continue;
}
magic = TRUE;
}
/*
* If there were any magic characters used then run the
* command using the shell.
*/
if (magic)
{
return system(cmd);
}
/*
* No magic characters were in the command, so we can do the fork
* and exec ourself.
*/
pid = fork();
if (pid < 0)
{
perror("fork failed");
return -1;
}
/*
* If we are the child process, then go execute the program.
*/
if (pid == 0)
childProcess(cmd);
/*
* We are the parent process.
* Wait for the child to complete.
*/
status = 0;
intCrlf = FALSE;
while (((pid = waitpid(pid, &status, 0)) < 0) && (errno == EINTR))
;
intCrlf = TRUE;
if (pid < 0)
{
fprintf(stderr, "Error from waitpid: %s", strerror(errno));
return -1;
}
if (WIFSIGNALED(status))
{
fprintf(stderr, "pid %ld: killed by signal %d\n",
(long) pid, WTERMSIG(status));
}
return WEXITSTATUS(status);
}
/*
* Here as the child process to try to execute the command.
* This is only called if there are no meta-characters in the command.
* This procedure never returns.
*/
static void
childProcess(const char * cmd)
{
const char ** argv;
int argc;
/*
* Close any extra file descriptors we have opened.
*/
while (--sourceCount >= 0)
{
if (sourcefiles[sourceCount] != stdin)
fclose(sourcefiles[sourceCount]);
}
/*
* Break the command line up into individual arguments.
* If this fails, then run the shell to execute the command.
*/
if (!makeArgs(cmd, &argc, &argv))
{
system(cmd);
exit(0);
}
/*
* Try to execute the program directly.
*/
execvp(argv[0], (char **) argv);
/*
* The exec failed, so try to run the command using the shell
* in case it is a shell script.
*/
if (errno == ENOEXEC)
{
system(cmd);
exit(0);
}
/*
* There was something else wrong, complain and exit.
*/
perror(argv[0]);
exit(1);
}
void
do_help(int argc, const char ** argv)
{
const CommandEntry * entry;
const char * str;
str = NULL;
if (argc == 2)
str = argv[1];
/*
* Check for an exact match, in which case describe the program.
*/
if (str)
{
for (entry = commandEntryTable; entry->name; entry++)
{
if (strcmp(str, entry->name) == 0)
{
printf("%s\n", entry->description);
printf("usage: %s %s\n", entry->name,
entry->usage);
return;
}
}
}
/*
* Print short information about commands which contain the
* specified word.
*/
for (entry = commandEntryTable; entry->name; entry++)
{
if ((str == NULL) || (strstr(entry->name, str) != NULL) ||
(strstr(entry->usage, str) != NULL))
{
printf("%-10s %s\n", entry->name, entry->usage);
}
}
}
void
do_alias(int argc, const char ** argv)
{
const char * name;
char * value;
Alias * alias;
int count;
char buf[CMD_LEN];
if (argc < 2)
{
count = aliasCount;
for (alias = aliasTable; count-- > 0; alias++)
printf("%s\t%s\n", alias->name, alias->value);
return;
}
name = argv[1];
if (argc == 2)
{
alias = findAlias(name);
if (alias)
printf("%s\n", alias->value);
else
fprintf(stderr, "Alias \"%s\" is not defined\n", name);
return;
}
if (strcmp(name, "alias") == 0)
{
fprintf(stderr, "Cannot alias \"alias\"\n");
return;
}
if (!makeString(argc - 2, argv + 2, buf, CMD_LEN))
return;
value = malloc(strlen(buf) + 1);
if (value == NULL)
{
fprintf(stderr, "No memory for alias value\n");
return;
}
strcpy(value, buf);
alias = findAlias(name);
if (alias)
{
free(alias->value);
alias->value = value;
return;
}
if ((aliasCount % ALIAS_ALLOC) == 0)
{
count = aliasCount + ALIAS_ALLOC;
if (aliasTable)
{
alias = (Alias *) realloc(aliasTable,
sizeof(Alias) * count);
}
else
alias = (Alias *) malloc(sizeof(Alias) * count);
if (alias == NULL)
{
free(value);
fprintf(stderr, "No memory for alias table\n");
return;
}
aliasTable = alias;
}
alias = &aliasTable[aliasCount];
alias->name = malloc(strlen(name) + 1);
if (alias->name == NULL)
{
free(value);
fprintf(stderr, "No memory for alias name\n");
return;
}
strcpy(alias->name, name);
alias->value = value;
aliasCount++;
}
/*
* Build aliases for all of the built-in commands which start with a dash,
* using the names without the dash.
*/
void
do_aliasall(int argc, const char **argv)
{
const CommandEntry * entry;
const char * name;
const char * newArgv[4];
for (entry = commandEntryTable; entry->name; entry++)
{
name = entry->name;
if (*name != '-')
continue;
newArgv[0] = "alias";
newArgv[1] = name + 1;
newArgv[2] = name;
newArgv[3] = NULL;
do_alias(3, newArgv);
}
}
/*
* Look up an alias name, and return a pointer to it.
* Returns NULL if the name does not exist.
*/
static Alias *
findAlias(const char * name)
{
Alias * alias;
int count;
count = aliasCount;
for (alias = aliasTable; count-- > 0; alias++)
{
if (strcmp(name, alias->name) == 0)
return alias;
}
return NULL;
}
void
do_source(int argc, const char ** argv)
{
readFile(argv[1]);
}
void
do_exec(int argc, const char ** argv)
{
const char * name;
name = argv[1];
while (--sourceCount >= 0)
{
if (sourcefiles[sourceCount] != stdin)
fclose(sourcefiles[sourceCount]);
}
argv[argc] = NULL;
execvp(name, (char **) argv + 1);
perror(name);
}
void
do_prompt(int argc, const char ** argv)
{
char * cp;
char buf[CMD_LEN];
if (!makeString(argc - 1, argv + 1, buf, CMD_LEN))
return;
cp = malloc(strlen(buf) + 2);
if (cp == NULL)
{
fprintf(stderr, "No memory for prompt\n");
return;
}
strcpy(cp, buf);
strcat(cp, " ");
if (prompt)
free(prompt);
prompt = cp;
}
void
do_unalias(int argc, const char ** argv)
{
Alias * alias;
while (--argc > 0)
{
alias = findAlias(*++argv);
if (alias == NULL)
continue;
free(alias->name);
free(alias->value);
aliasCount--;
alias->name = aliasTable[aliasCount].name;
alias->value = aliasTable[aliasCount].value;
}
}
/*
* Display the prompt string.
*/
static void
showPrompt(void)
{
const char * cp;
cp = "> ";
if (prompt)
cp = prompt;
write(STDOUT, cp, strlen(cp));
}
static void
catchInt(int val)
{
signal(SIGINT, catchInt);
intFlag = TRUE;
if (intCrlf)
write(STDOUT, "\n", 1);
}
static void
catchQuit(int val)
{
signal(SIGQUIT, catchQuit);
intFlag = TRUE;
if (intCrlf)
write(STDOUT, "\n", 1);
}
/*
* Print the usage information and quit.
*/
static void
usage(void)
{
fprintf(stderr, "Stand-alone shell (version %s)\n", version);
fprintf(stderr, "\n");
fprintf(stderr, "Usage: sash [-a] [-q] [-f fileName] [-c command] [-p prompt] [-i]\n");
exit(1);
}
/* END CODE */
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