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/*
* arglist.c -- Routines for handling argument lists for execvp() and friends
*
* This code is Copyright (c) 2013, by the authors of nmh. See the
* COPYRIGHT file in the root directory of the nmh distribution for
* complete copyright information.
*/
#include <h/mh.h>
#include <h/utils.h>
/*
* Split up a command into an appropriate array to pass to execvp()
* or similar function. Returns an allocated argv[] array.
*
* Function arguments:
*
* command - String to split up
* file - the first argument to "command", suitable for the first argument
* to execvp(). Returns allocated memory that must be free()d.
* argp - Index to last element (NULL) of returned argv[] array.
*
* Our basic algorithm is this:
*
* - If there are no spaces or shell metacharacters in "command", then
* take it as-is.
* - If there are spaces in command, space-split command string.
* - If we have shell metacharacters, run the command using
* /bin/sh -c 'command "$@"'. In this case, any additional arguments
* appended to the arglist will be expanded by "$@".
*
* In all cases additional arguments can be added to the argv[] array.
*/
/* Shell metacharacters we use to trigger a call to the shell */
#define METACHARS "$&*(){}[]'\";\\|?<>~`\n"
char **
argsplit(char *command, char **file, int *argp)
{
char **argvarray, *p;
int space = 0, metachar = 0, i;
for (p = command; *p; p++) {
if (*p == ' ' || *p == '\t') {
space = 1;
} else if (strchr(METACHARS, *p)) {
metachar = 1;
break;
}
}
argvarray = (char **) mh_xmalloc((sizeof(char **) * (MAXARGS + 5)));
/*
* The simple case - no spaces or shell metacharacters
*/
if (!space && !metachar) {
argvarray[0] = getcpy(r1bindex(command, '/'));
argvarray[1] = NULL;
*file = getcpy(command);
if (argp)
*argp = 1;
return argvarray;
}
/*
* Spaces, but no shell metacharacters; space-split into seperate
* arguments
*/
if (space && !metachar) {
char **split;
p = getcpy(command);
split = brkstring(p, " \t", NULL);
if (split[0] == NULL) {
adios(NULL, "Invalid blank command found");
}
argvarray[0] = getcpy(r1bindex(split[0], '/'));
for (i = 1; split[i] != NULL; i++) {
if (i > MAXARGS) {
adios(NULL, "Command exceeded argument limit");
}
argvarray[i] = getcpy(split[i]);
}
argvarray[i] = NULL;
*file = getcpy(split[0]);
if (argp)
*argp = i;
free(p);
return argvarray;
}
/*
* Remaining option - pass to the shell.
*
* Some notes here:
*
* - The command passed to "sh -c" is actually:
* command "$@"
*
* If there are additional arguments they will be expanded by the
* shell, otherwise "$@" expands to nothing.
*
* - Every argument after the -c string gets put into positional
* parameters starting at $0, but $@ starts expanding with $1.
* So we put in a dummy argument (we just use /bin/sh)
*/
*file = getcpy("/bin/sh");
argvarray[0] = getcpy("sh");
argvarray[1] = getcpy("-c");
argvarray[2] = getcpy(command);
argvarray[2] = add(" \"$@\"", argvarray[2]);
argvarray[3] = getcpy("/bin/sh");
argvarray[4] = NULL;
if (argp)
*argp = 4;
return argvarray;
}
/*
* Free our argument array
*/
void
arglist_free(char *command, char **argvarray)
{
int i;
if (command != NULL)
free(command);
if (argvarray != NULL) {
for (i = 0; argvarray[i] != NULL; i++)
free(argvarray[i]);
free(argvarray);
}
}
/*
* Similar in functionality to argsplit, but is designed to deal with
* a msgs_array.
*/
void
argsplit_msgarg(struct msgs_array *msgs, char *command, char **program)
{
int argp, i;
char **vec;
vec = argsplit(command, program, &argp);
/*
* As usual, there is lousy memory management in nmh. Nothing ever
* free's the msgs_array, and a lot of the arguments are allocated
* from static memory. I could have app_msgarg() allocate new
* memory for each pointer, but for now I decided to stick with
* the existing interface; maybe that will be revisited later.
* So we'll just copy over our pointers and free the pointer list
* (not the actual pointers themselves). Note that we don't
* include a trailing NULL, since we are expecting the application
* to take care of that.
*/
for (i = 0; i < argp; i++) {
app_msgarg(msgs, vec[i]);
}
free(vec);
}
/*
* Insert a arglist vector into the beginning of an struct msgs array
*
* Uses by some programs (e.g., show) who want to decide which proc
* to use after the argument vector has been constructed
*/
#ifndef MAXMSGS
#define MAXMSGS 256
#endif
void
argsplit_insert(struct msgs_array *msgs, char *command, char **program)
{
int argp, i;
char **vec;
vec = argsplit(command, program, &argp);
/*
* Okay, we want to shuffle all of our arguments down so we have room
* for argp number of arguments. This means we need to know about
* msgs_array internals. If that changes, we need to change this
* code here.
*/
if (msgs->size + argp >= msgs->max) {
msgs->max += MAXMSGS > argp ? MAXMSGS : argp;
msgs->msgs = mh_xrealloc(msgs->msgs, msgs->max * sizeof(*msgs->msgs));
}
for (i = msgs->size - 1; i >= 0; i--)
msgs->msgs[i + argp] = msgs->msgs[i];
msgs->size += argp;
/*
* Now fill in the arguments at the beginning of the vector.
*/
for (i = 0; i < argp; i++)
msgs->msgs[i] = vec[i];
free(vec);
}
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