| 16 |
|
#include <process.h> /* getpid() and others */ |
| 17 |
|
#define getpid _getpid |
| 18 |
|
#define execv _execv |
| 19 |
+ |
#define execvp _execvp |
| 20 |
|
#else |
| 21 |
|
#include <sys/param.h> |
| 22 |
|
#include <sys/types.h> |
| 38 |
|
platform independent RT_PID. |
| 39 |
|
*/ |
| 40 |
|
|
| 41 |
+ |
/* On Unix, we can set flags and assign descriptors before opening a |
| 42 |
+ |
process, coupling an existing input or output to the new process rather |
| 43 |
+ |
than opening both pipes. If PF_FILT_INP is passed in the flags member of |
| 44 |
+ |
SUBPROC, then the given r stream will be attached to the standard input |
| 45 |
+ |
of the child process, and subsequent reads from that descriptor in the |
| 46 |
+ |
parent get data from the standard output of the child, instead. The |
| 47 |
+ |
returned w descriptor is set to -1, since there is no longer any way |
| 48 |
+ |
to write to the input of the child. The default r descriptor of 0 will |
| 49 |
+ |
compel the child to act as a filter on the standard input of the parent. |
| 50 |
+ |
Whatever r handle you specify, the child will filter its read operations. |
| 51 |
+ |
Note that this should be called before anything has been buffered using r. |
| 52 |
+ |
If PF_FILT_OUT is set in flags, then the given w stream will be |
| 53 |
+ |
attached to the standard output of the child, and subsequent writes |
| 54 |
+ |
to that descriptor in the parent send data to the standard input |
| 55 |
+ |
of the child. The returned r descriptor is set to -1, since |
| 56 |
+ |
there is no output to read from any longer in the child. The |
| 57 |
+ |
default w descriptor of 1 will cause the child to act as a filter |
| 58 |
+ |
on the output of the parent. Make sure to call fflush(stdout) first |
| 59 |
+ |
if any data was buffered. It is illegal to set both PF_FILT_INP and |
| 60 |
+ |
PF_FILT_OUT, as a circular process is guaranteed to hang. |
| 61 |
+ |
|
| 62 |
+ |
If you want behavior similar to popen(cmd, "w") (again Unix-only), |
| 63 |
+ |
keeping stdout open in parent, use a duplicate descriptor like so: |
| 64 |
+ |
{ |
| 65 |
+ |
SUBPROC rtp = sp_inactive; |
| 66 |
+ |
FILE *fout; |
| 67 |
+ |
fflush(stdout); |
| 68 |
+ |
rtp.w = dup(fileno(stdout)); |
| 69 |
+ |
rtp.flags |= PF_FILT_OUT; |
| 70 |
+ |
if (open_process(&rtp, cmd_argv) <= 0) { |
| 71 |
+ |
perror(cmd_argv[0]); exit(1); |
| 72 |
+ |
} |
| 73 |
+ |
fout = fdopen(rtp.w, "w"); |
| 74 |
+ |
...write data to filter using fout until finished... |
| 75 |
+ |
fclose(fout); |
| 76 |
+ |
if (close_process(&rtp)) { |
| 77 |
+ |
perror(cmd_argv[0]); exit(1); |
| 78 |
+ |
} |
| 79 |
+ |
...can continue sending data directly to stdout... |
| 80 |
+ |
} |
| 81 |
+ |
We could also have called open_process() after fdopen() above, or after |
| 82 |
+ |
using fopen() on a file if we wanted to insert our filter before it. |
| 83 |
+ |
A similar sequence may be used to filter from stdin without closing |
| 84 |
+ |
it, though process termination becomes more difficult with two readers. |
| 85 |
+ |
Filtering input from a file works better, since the file is then read by |
| 86 |
+ |
the child only, as in: |
| 87 |
+ |
{ |
| 88 |
+ |
SUBPROC rtp = sp_inactive; |
| 89 |
+ |
FILE *fin = fopen(fname, "r"); |
| 90 |
+ |
if (fin == NULL) { |
| 91 |
+ |
open_error(fname); exit(1); |
| 92 |
+ |
} |
| 93 |
+ |
rtp.r = fileno(fin); |
| 94 |
+ |
rtp.flags |= PF_FILT_INP; |
| 95 |
+ |
if (open_process(&rtp, cmd_argv) <= 0) { |
| 96 |
+ |
perror(cmd_argv[0]); fclose(fin); exit(1); |
| 97 |
+ |
} |
| 98 |
+ |
...read filtered file data from fin until EOF... |
| 99 |
+ |
fclose(fin); |
| 100 |
+ |
if (close_process(&rtp)) { |
| 101 |
+ |
perror(cmd_argv[0]); exit(1); |
| 102 |
+ |
} |
| 103 |
+ |
} |
| 104 |
+ |
*/ |
| 105 |
|
|
| 106 |
+ |
|
| 107 |
|
#ifndef PIPE_BUF |
| 108 |
|
#ifdef PIPSIZ |
| 109 |
|
#define PIPE_BUF PIPSIZ |
| 115 |
|
#endif |
| 116 |
|
#endif |
| 117 |
|
#endif |
| 118 |
+ |
/* process flags */ |
| 119 |
+ |
#define PF_RUNNING 1 /* process is running */ |
| 120 |
+ |
#define PF_FILT_INP 2 /* use assigned read descriptor */ |
| 121 |
+ |
#define PF_FILT_OUT 4 /* use assigned write descriptor */ |
| 122 |
|
|
| 123 |
|
typedef struct { |
| 124 |
< |
int r; /* read handle */ |
| 125 |
< |
int w; /* write handle */ |
| 126 |
< |
int running; /* doing something */ |
| 127 |
< |
RT_PID pid; /* process ID */ |
| 124 |
> |
int flags; /* what is being done */ |
| 125 |
> |
int r; /* read handle */ |
| 126 |
> |
int w; /* write handle */ |
| 127 |
> |
RT_PID pid; /* process ID */ |
| 128 |
|
} SUBPROC; |
| 129 |
|
|
| 130 |
< |
#define SP_INACTIVE {-1,-1,0,0} /* for static initializations */ |
| 130 |
> |
#define SP_INACTIVE {0,0,1,-1} /* for static initializations */ |
| 131 |
|
|
| 132 |
|
#define close_process(pd) close_processes(pd,1) |
| 133 |
|
|
| 143 |
|
extern int win_nice(int inc); |
| 144 |
|
#endif |
| 145 |
|
|
| 146 |
+ |
extern SUBPROC sp_inactive; |
| 147 |
|
|
| 148 |
|
#ifdef __cplusplus |
| 149 |
|
} |
