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/* $Id: custom.c,v 1.2 1999/07/01 01:39:58 fraserm Exp $
$Log: custom.c,v $
Revision 1.2 1999/07/01 01:39:58 fraserm
word 0
Revision 1.1 1999/05/26 23:51:20 fraserm
Initial revision
*/
/* custom fields - i.e. incorporate external commands */
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/wait.h>
#include "limo.h"
/* execute the command in cmdfmt with the file fname; assumes fname is a valid
filename from current location */
char *get_custom(int argc, char *argv[], struct custcmd *cmdfmt, char *fname)
{
char cmdbuf[CMDMAX];
char output[CMDOUTMAX];
char *retbuf = NULL;
int p[2]; /* pipe file descriptors */
FILE *f; /* the stdio'd version of the read side (p[0]) of the pipe */
pid_t child;
int status; /* status return of the child process */
char *my_argv[4];
int ch;
int i, curr;
/* ssize_t rv; */
/* make the command */
if (snprintf(cmdbuf, CMDMAX, cmdfmt->cmd, fname) == -1) {
retbuf = "Bad-Command";
}
else { /* made command ok */
/* create a pipe */
if (pipe(p) == -1) {
fprintf(stderr, "%s: pipe: %s\n", argv[0], strerror(errno));
retbuf = "Pipe Error";
}
else { /* made pipe ok */
/* printf("Pipe fds %d & %d\n", p[0], p[1]); */
/* split into two processes */
if ((child = fork()) == -1) {
fprintf(stderr, "%s: fork: %s\n", argv[0], strerror(errno));
}
else { /* forked ok */
if (child == 0) { /* in the child, dup() all the fds and run the
command */
/* make the writing end of the pipe the standard out and err for
this process */
if (dup2(p[1], 1) == -1 || dup2(p[1], 2) == -1) {
fprintf(stderr, "%s: dup2: %s\n", argv[0], strerror(errno));
close(p[1]);
exit(0); /* just exits the sub-process, mind! */
}
/* execute the command */
my_argv[0] = "sh";
my_argv[1] = "-c";
my_argv[2] = cmdbuf;
my_argv[3] = NULL;
execv("/bin/sh", my_argv);
exit(127);
}
else { /* in the parent, read the child's output */
/* let's make it into a standard IO object to make things simpler */
if ((f = fdopen(p[0], "r")) == NULL) {
fprintf(stderr, "%s: fdopen: %s\n", argv[0], strerror(errno));
retbuf = "Bad-Pipe-Read";
}
else { /* fdopened ok */
/* skip lines as required */
ch = fgetc(f);
for (curr = 1; curr < cmdfmt->linenum; ++curr) {
while (ch != EOF && ch != '\n') {
ch = fgetc(f);
}
}
if (ch == EOF) {
retbuf = "Not-Enough-Lines";
}
else {
/* right, skip whitespace first */
while (ch != EOF
&& (ch == ' ' || ch == '\r' || ch == '\t')) {
ch = fgetc(f);
}
if (ch == EOF || ch == '\n') {
retbuf = "Not-Enough-Lines";
}
else {
if (cmdfmt->wordnum != 0) { /* 0 means the whole line */
/* skip enough words */
for (curr = 1; curr < cmdfmt->wordnum; ++curr) {
/* skip a word */
while (ch != EOF
&& ch != ' ' && ch != '\t' && ch != '\r' && ch != '\n') {
ch = fgetc(f);
}
if (ch == EOF || ch == '\n') {
break; /* EOF or end-of-line is game over */
}
/* skip the whitespace following it */
while (ch != EOF &&
(ch == ' ' || ch == '\r' || ch == '\t')) {
ch = fgetc(f);
}
if (ch == EOF || ch == '\n') {
break;
}
}
}
if (ch == EOF || ch == '\n') { /* must have hit something we
don't want */
retbuf = "Not-Enough-Words";
}
else {
if (ch != EOF) {
ungetc(ch, f); /* push the last one back */
/* read into the output buffer until we get a whitespace
or run out of buffer, or if wordnum is 0, until the
end of the line */
for (i = 0;
i < CMDOUTMAX-1 && (ch = fgetc(f)) != EOF;
++i) {
if (ch == '\n' || ch == '\r'
|| (cmdfmt->wordnum > 0
&& (ch == ' ' || ch == '\t'))) {
break;
}
output[i] = ch;
}
output[i] = '\0'; /* terminate the string properly */
}
}
}
}
/* close this end of the pipe */
fclose(f);
/* wait for the process to terminate */
if (waitpid(child, &status, 0) != child) {
fprintf(stderr, "%s: waitpid: %s\n", argv[0], strerror(errno));
}
/* did command succeed? */
if (WEXITSTATUS(status) != 0) {
retbuf = "-";
}
else {
if (retbuf == NULL) {
/* get a char buffer to return the output in */
if ((retbuf = (char *) malloc(i+1)) == NULL) {
fprintf(stderr, "%s: malloc: %s\n", argv[0],
strerror(errno));
retbuf = "Bad-malloc";
}
else { /* malloced ok */
strcpy(retbuf, output);
}
}
}
}
}
}
close(p[0]); /* the reading side */
close(p[1]); /* the writing side */
}
}
return retbuf;
}
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