mars-nwe/examples/unxcomm.c
2011-11-13 00:38:57 +01:00

69 lines
1.8 KiB
C

/* simple UNX program to work together with 'comm' */
#include <stdio.h>
#include <fcntl.h>
static char **build_argv(int bufsize, char *command, int len)
/* routine returns **argv for use with execv routines */
{
int offset = ((len+4) / 4) * 4; /* aligned offset for **argv */
int components = (bufsize - offset) / 4;
if (components-- > 1) { /* minimal argv[0] + NULL */
char **argv = (char **)(command+offset);
char **pp = argv;
char *p = command;
char c;
int i=0;
*pp = p;
*(p+len) = 0;
while ((0 != (c = *p++)) && i < components) {
if (c == 10 || c == 13) {
*(p-1) = '\0';
break;
} else if (c == 32 || c == '\t') {
*(p-1) = '\0';
if (*p != 32 && *p != '\t' && *p != 10 && *p != 13) {
*(++pp)=p;
i++;
}
} else if (!i && c == '/') { /* here i must get argv[0] */
*pp=p;
}
}
if (*pp && !**pp) *pp=NULL;
else
*(++pp)=NULL;
return(argv);
}
return(NULL);
}
#define MAXARGLEN 1024
int main(int argc, char *argv[])
{
int status=fcntl(0, F_GETFL);
int size;
char buf[MAXARGLEN+1024];
if (status != -1) fcntl(0, F_SETFL, status|O_NONBLOCK);
close(2);
dup2(1,2);
if (-1 < (size=read(0, buf, MAXARGLEN))){
char **argvv=build_argv(sizeof(buf), buf, size);
if (argvv) {
char path[300];
execv(buf, argvv);
sprintf(path, "/usr/bin/%s", *argvv);
execv(path, argvv);
sprintf(path, "/bin/%s", *argvv);
execv(path, argvv);
sprintf(path, "/usr/sbin/%s", *argvv);
execv(path, argvv);
sprintf(path, "/sbin/%s", *argvv);
execv(path, argvv);
fprintf(stderr, "%s:\tCould not find program '%s'\n", *argv, buf);
exit(1);
}
}
fprintf(stderr, "%s:\tGot no paras\n", *argv);
exit(1);
}