4.3BSD - /usr/src/new/spms/src/lib/pgrep/grep.c

   1: /* $Header$ */
   2: 
   3: /*
   4:  * Author: Peter J. Nicklin
   5:  */
   6: #include <signal.h>
   7: #include <stdio.h>
   8: #include <sys/param.h>
   9: #include "null.h"
  10: #include "slist.h"
  11: #include "system.h"
  12: 
  13: #define MAXNAMLEN   255
  14: #define READ        0
  15: #define WRITE       1
  16: 
  17: static int popen_pid;           /* process identity */
  18: 
  19: /*
  20:  * closegrep() closes the pipe from the grep command and returns the
  21:  * the exit status of the grep command.
  22:  */
  23: closegrep(fp)
  24:     FILE *fp;           /* pipe file pointer */
  25: {
  26:     register (*hstat)();        /* hangup function pointer */
  27:     register (*istat)();        /* interrupt function pointer */
  28:     register (*qstat)();        /* quit function pointer */
  29:     register int w;         /* a child id */
  30:     int status;         /* child return status */
  31: 
  32:     fclose(fp);
  33: 
  34:     istat = signal(SIGINT, SIG_IGN);
  35:     qstat = signal(SIGQUIT, SIG_IGN);
  36:     hstat = signal(SIGHUP, SIG_IGN);
  37: 
  38:     while ((w = wait(&status)) != popen_pid && w != -1)
  39:         continue;
  40: 
  41:     signal(SIGINT, istat);
  42:     signal(SIGQUIT, qstat);
  43:     signal(SIGHUP, hstat);
  44: 
  45:     status >>= NBBY;
  46:     status &=  0xff;
  47:     return(status);
  48: }
  49: 
  50: 
  51: 
  52: /*
  53:  * grep() returns a singly-linked list of file names from the grep
  54:  * command. NULL is returned on error.
  55:  */
  56: SLIST *
  57: grep(greppath, grepargv)
  58:     char *greppath;         /* grep command path */
  59:     char **grepargv;        /* grep argv */
  60: {
  61:     char filename[MAXNAMLEN + 1];   /* receiving filename buffer */
  62:     char *readgrep();       /* read input from grep */
  63:     char *slappend();       /* append key */
  64:     FILE *fp;           /* input stream from grep */
  65:     FILE *opengrep();       /* open pipe to grep */
  66:     int closegrep();        /* close pipe to grep */
  67:     SLIST *filelist;        /* list of file names */
  68:     SLIST *slinit();        /* initialize list */
  69: 
  70:     if ((fp = opengrep(greppath, grepargv)) == NULL)
  71:         return(NULL);
  72: 
  73:     filelist = slinit();
  74: 
  75:     while (readgrep(filename, fp) != NULL)
  76:         if (slappend(filename, filelist) == NULL)
  77:             return(NULL);
  78: 
  79:     if (closegrep(fp) == 2)
  80:         return(NULL);
  81:     return(filelist);
  82: }
  83: 
  84: 
  85: 
  86: /*
  87:  * opengrep() opens a pipe to read from the grep command. A file
  88:  * pointer is returned, or NULL on error.
  89:  */
  90: FILE *
  91: opengrep(greppath, grepargv)
  92:     char *greppath;         /* grep command path */
  93:     char **grepargv;        /* grep argv */
  94: {
  95:     FILE *fdopen();         /* associate stream with file descrip */
  96:     int p[2];           /* pipe file descriptors */
  97: 
  98:     if (pipe(p) < 0)
  99:         return(NULL);
 100:     if ((popen_pid = FORK()) == 0)
 101:         {
 102:         close(p[READ]);
 103:         dup2(p[WRITE], WRITE);
 104:         close(p[WRITE]);
 105:         execv(greppath, grepargv);
 106:         _exit(1);
 107:         }
 108:     if (popen_pid == -1)
 109:         return(NULL);
 110:     close(p[WRITE]);
 111:     return(fdopen(p[READ], "r"));
 112: }
 113: 
 114: 
 115: 
 116: /*
 117:  * readgrep() reads a line from the grep stream. The newline character
 118:  * is replaced by a null character. Returns buf, or NULL at EOF.
 119:  */
 120: char *
 121: readgrep(buf, fp)
 122:     char *buf;          /* receiving buffer */
 123:     register FILE *fp;      /* input stream */
 124: {
 125:     register char *bp;      /* receiving buffer pointer */
 126:     register int c;         /* current character */
 127: 
 128:     bp = buf;
 129:     while((c = getc(fp)) != '\n' && c != EOF)
 130:         *bp++ = c;
 131:     if (c == EOF && bp == buf)
 132:         return(NULL);
 133:     *bp = '\0';
 134:     return(buf);
 135: }

Defined functions

Defined variables

Defined macros