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Annotation of 43BSDTahoe/new/spms/src/lib/pgrep/grep.c, revision 1.1

1.1     ! root        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: }

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