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#include <linux/limits.h>
#include <unistd.h>
#include <dirent.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
static void
die(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
fprintf(stderr, "wd: ");
vfprintf(stderr, fmt, ap);
if (*fmt && fmt[strlen(fmt)-1] == ':') {
fputc(' ', stderr);
perror(NULL);
} else {
fputc('\n', stderr);
}
va_end(ap);
exit(1);
}
static void
findbin(char *dst, const char *name)
{
char *env, *tok;
struct dirent *ent;
int len;
DIR *d;
env = getenv("PATH");
if (!env) die("PATH not set");
env = strdup(env);
if (!env) die("strdup:");
for (tok = strtok(env, ":"); tok; tok = strtok(NULL, ":")) {
if (!*tok) continue;
d = opendir(tok);
if (!d) continue;
while ((ent = readdir(d))) {
if (!strcmp(ent->d_name, name)) {
closedir(d);
free(env);
len = snprintf(dst, PATH_MAX,
"%s/%s", tok, ent->d_name);
if (len > PATH_MAX) abort();
return;
}
}
closedir(d);
}
free(env);
die("'%s' not found", name);
}
int
main(int argc, char **argv)
{
char binpath[PATH_MAX];
if (argc < 3) {
fprintf(stderr, "Usage: wd DIR CMD..\n");
return 1;
}
if (chdir(argv[1])) die("chdir:");
findbin(binpath, argv[2]);
execv(binpath, argv + 2);
die("execv:");
}
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