1 /* system.c -- UNIX version */
5 * 14407 SW Teal Blvd. #C
11 /* This file contains a new version of the system() function and related stuff.
14 * system(cmd) - run a single shell command
15 * wildcard(names) - expand wildcard characters in filanames
16 * filter(m,n,cmd) - run text lines through a filter program
18 * This is probably the single least portable file in the program. The code
19 * shown here should work correctly if it links at all; it will work on UNIX
20 * and any O.S./Compiler combination which adheres to UNIX forking conventions.
26 extern char **environ
;
30 /* This is a new version of the system() function. The only difference
31 * between this one and the library one is: this one uses the o_shell option.
34 char *cmd
; /* a command to run */
36 int pid
; /* process ID of child */
38 int status
; /* exit status of the command */
41 signal(SIGINT
, SIG_IGN
);
51 /* for the child, close all files except stdin/out/err */
52 for (status
= 3; status
< 60 && (close(status
), errno
!= EINVAL
); status
++)
56 signal(SIGINT
, SIG_DFL
);
59 execle(o_shell
, o_shell
, (char *)0, environ
);
63 execle(o_shell
, o_shell
, "-c", cmd
, (char *)0, environ
);
65 msg("execle(\"%s\", ...) failed", o_shell
);
66 exit(1); /* if we get here, the exec failed */
72 } while (died
>= 0 && died
!= pid
);
78 signal(SIGINT
, (void (*)()) trapint
);
80 signal(SIGINT
, trapint
);
87 /* This private function opens a pipe from a filter. It is similar to the
88 * system() function above, and to popen(cmd, "r").
91 char *cmd
; /* the filter command to use */
92 int in
; /* the fd to use for stdin */
94 int r0w1
[2];/* the pipe fd's */
99 return -1; /* pipe failed */
102 /* The parent process (elvis) ignores signals while the filter runs.
103 * The child (the filter program) will reset this, so that it can
106 signal(SIGINT
, SIG_IGN
);
114 /* close the "read" end of the pipe */
117 /* redirect stdout to go to the "write" end of the pipe */
132 /* the filter should accept SIGINT signals */
133 signal(SIGINT
, SIG_DFL
);
135 /* exec the shell to run the command */
136 execle(o_shell
, o_shell
, "-c", cmd
, (char *)0, environ
);
137 exit(1); /* if we get here, exec failed */
139 default: /* parent */
140 /* close the "write" end of the pipe */
151 /* This private function opens a pipe from a filter. It is similar to the
152 * system() function above, and to popen(cmd, "r").
155 char *cmd
; /* the filter command to use */
156 int in
; /* the fd to use for stdin */
158 return osk_popen(cmd
, "r", in
, 0);
164 /* This function closes the pipe opened by rpipe(), and returns 0 for success */
173 signal(SIGINT
, (void (*)()) trapint
);
175 signal(SIGINT
, trapint
);
182 /* This function expands wildcards in a filename or filenames. It does this
183 * by running the "echo" command on the filenames via the shell; it is assumed
184 * that the shell will expand the names for you. If for any reason it can't
185 * run echo, then it returns the names unmodified.
189 #define PROG "wildcard "
197 char *wildcard(names
)
203 We could use expand() [vmswild.c], but what's the point on VMS?
204 Anyway, echo is the wrong thing to do, it takes too long to build
205 a subprocess on VMS and any "echo" program would have to be supplied
206 by elvis. More importantly, many VMS utilities expand names
207 themselves (the shell doesn't do any expansion) so the concept is
217 /* build the echo command */
218 if (names
!= tmpblk
.c
)
220 /* the names aren't in tmpblk.c, so we can do it the easy way */
221 strcpy(tmpblk
.c
, PROG
);
222 strcat(tmpblk
.c
, names
);
226 /* the names are already in tmpblk.c, so shift them to make
227 * room for the word "echo "
229 for (s
= names
+ strlen(names
) + 1, d
= s
+ PROGLEN
; s
> names
; )
233 strncpy(names
, PROG
, PROGLEN
);
236 /* run the command & read the resulting names */
237 fd
= rpipe(tmpblk
.c
, 0);
238 if (fd
< 0) return names
;
242 j
= tread(fd
, tmpblk
.c
+ i
, BLKSIZE
- i
);
247 if (rpclose(fd
) == 0 && j
== 0 && i
< BLKSIZE
&& i
> 0)
249 tmpblk
.c
[i
-1] = '\0'; /* "i-1" so we clip off the newline */
259 /* This function runs a range of lines through a filter program, and replaces
260 * the original text with the filtered version. As a special case, if "to"
261 * is MARK_UNSET, then it runs the filter program with stdin coming from
262 * /dev/null, and inserts any output lines.
264 int filter(from
, to
, cmd
)
265 MARK from
, to
; /* the range of lines to filter */
266 char *cmd
; /* the filter command */
268 int scratch
; /* fd of the scratch file */
269 int fd
; /* fd of the pipe from the filter */
270 char scrout
[50]; /* name of the scratch out file */
271 MARK
new; /* place where new text should go */
274 /* write the lines (if specified) to a temp file */
279 strcpy(scrout
, o_directory
);
280 if ((i
=strlen(scrout
)) && !strchr("\\/:", scrout
[i
-1]))
282 strcpy(scrout
+i
, SCRATCHOUT
+3);
284 sprintf(scrout
, SCRATCHOUT
, o_directory
);
287 cmd_write(from
, to
, CMD_BANG
, 0, scrout
);
289 /* use those lines as stdin */
290 scratch
= open(scrout
, O_RDONLY
);
302 /* start the filter program */
305 VMS doesn't know a thing about file descriptor 0. The rpipe
306 concept is non-portable. Hence we need a file name argument.
308 fd
= rpipe(cmd
, scratch
, scrout
);
310 fd
= rpipe(cmd
, scratch
);
324 /* adjust MARKs for whole lines, and set "new" */
325 from
&= ~(BLKSIZE
- 1);
328 to
&= ~(BLKSIZE
- 1);
334 new = from
+ BLKSIZE
;
338 /* Reading from a VMS mailbox (pipe) is record oriented... */
339 # define tread vms_pread
342 /* repeatedly read in new text and add it */
343 while ((i
= tread(fd
, tmpblk
.c
, BLKSIZE
- 1)) > 0)
348 /* What! An advantage to record oriented reads? */
350 new = (new & ~(BLKSIZE
- 1)) + BLKSIZE
;
352 for (i
= 0; tmpblk
.c
[i
]; i
++)
354 if (tmpblk
.c
[i
] == '\n')
356 new = (new & ~(BLKSIZE
- 1)) + BLKSIZE
;
367 /* delete old text, if any */
377 rptlines
= -rptlines
;