Брайан Керниган - UNIX — универсальная среда программирования

char *dir, *guess, *best;

{

/* set best, return distance 0..3 */

int d, nd, fd;

struct {

ino_t ino;

char name[DIRSIZ+1]; /* 1 more than in dir.h */

} nbuf;

nbuf.name[DIRSIZ] = '\0'; /* +1 for terminal '\0' */

if (dir[0] == '\0') /* current directory */

dir = ".";

d = 3; /* minimum distance */

if ((fd=open(dir, 0)) == -1)

return d;

while (read(fd, (char*)&nbuf, sizeof(struct direct)) > 0)

if (nbuf.ino) {

nd = spdist(nbuf.name, guess);

if (nd <= d && nd != 3) {

strcpy(best, nbuf.name);

d = nd;

if (d == 0) /* exact match */

break;

}

}

close(fd);

return d;

}

/* spdist: return distance between two names */

/*

* very rough spelling metric:

* 0 if the strings are identical

* 1 if two chars are transposed

* 2 if one char wrong, added or deleted

* 3 otherwise

*/

#define EQ(s,t) (strcmp(s,t) == 0)

spdist(s, t)

char *s, *t;

{

while (*s++ == *t)

if (*t++ == '\0')

return 0; /* exact match */

if (*--s) {

if (*t) {

if (s[1] && t[1] && *s == t[1] && *t == s[1] && EQ(s+2, t+2))

return 1; /* transposition */

if (EQ(s+1, t+1))

return 2; /* 1 char mismatch */

}

if (EQ(s+1, t))

return 2; /* extra character */

}

if (*t && EQ(s, t+1))

return 2; /* missing character */

return 3;

}

strindex(s, t) /* return index of t in s, -1 if none */

char *s, *t;

{

int i, n;

n = strlen(t);

for (i = 0; s[i] != '\0'; i++)

if (strncmp(s+i, t, n) == 0)

return i;

return -1;

}

/* sv: save new files */

#include

#include

#include

#include

char *progname;

main(argc, argv)

int argc;

char *argv[];

{

int i;

struct stat stbuf;

char *dir = argv[argc-1];

progname = argv[0];

if (argc <= 2)

error ("Usage: %s files... dir", progname);

if (stat(dir, festbuf) == -1)

error("can't access directory %s", dir);

if ((stbuf.st_mode & S_IFMT) != S_IFDIR)

error("%s is not a directory", dir);

for (i = 1; i < argc-1; i++)

sv(argv[i], dir);

exit(0);

}

sv(file, dir) /* save file in dir */

char *file, *dir;

{

struct stat sti, sto;

int fin, fout, n;

char target[BUFSIZ], buf[BUFSIZ], *index();

sprintf(target, "%s/%s", dir, file);

if (index(file, '/') != NULL) /* strchr() in some systems */

error("won't handle '/'s in %s", file);

if (stat(file, &sti) == -1)

error("can't stat %s", file);

if (stat(target, &sto) == -1) /* target not present */

sto.st_mtime = 0; /* so make it look old */

if (sti.st_mtime < sto.st_mtime) /* target is newer */

fprintf(stderr, "%s: %s not copied\n", progname, file);

else if ((fin = open(file, 0)) == -1)

error("can't open file %s", file);

else if ((fout = creat(target, sti.st_mode)) == -1)

error("can't create %s", target);

while ((n = read(fin, buf, sizeof buf)) > 0)

if (write(fout, buf, n) != n)

error("error writing %s", target);

close(fin);

close(fout);

}

#include "error.c"

#include

system(s) /* run command line s */

char *s;

{

int status, pid, w, tty;

int (*istat)(), (*qstat)();

...

if ((pid = fork()) == 0) {

...

execlp("sh", "sh", "-c", s, (char*)0);

exit(127);

}

...

istat = signal(SIGINT, SIG_IGN);

qstat = signal(SIGQUIT, SIG_IGN);

while ((w = wait(&status)) != pid && w != -1)

;

if (w == -1)

status = -1;

signal(SIGINT, istat);

signal(SIGQUIT, qstat);

return status;

}

/*

* Safer version of system for interactive programs

*/

#include

#include

system(s) /* run command line s */

char *s;

{

int status, pid, w, tty;

int (*istat)(), (*qstat)();

extern char *progname;

fflush(stdout);

tty = open("/dev/tty", 2);

if (tty == -1) {

fprintf (stderr, "%s: can't open /dev/tty\n", progname);

return -1;

}

if ((pid = fork()) == 0) {

close(0);

dup(tty);

close(1);

dup(tty);

close(2);

dup(tty);

close(tty);

execlp("sh", "sh", "-c", s, (char*)0);

exit(127);

}

close(tty);

istat = signal(SIGINT, SIG_IGN);

qstat = signal(SIGQUIT, SIG_IGN);

while ((w = wait(&status)) != pid && w != -1)

;

if (w == -1)

status = -1;

signal(SIGINT, istat);

signal(SIGQUIT, qstat);

return status;

}

/* timeout: set time limit on a process */

#include

#include

int pid; /* child process id */

char *progname;

main(argc, argv)

int argc;

char *argv[];

{

int sec = 10, status, onalarm();

progname = argv[0];

if (argc > 1 && argv[1][0] == '-') {

sec = atoi(&argv[1][1]);

argc--;