diff options
Diffstat (limited to 'src/pwd.c')
-rw-r--r-- | src/pwd.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/src/pwd.c b/src/pwd.c new file mode 100644 index 0000000..8ccd28b --- /dev/null +++ b/src/pwd.c @@ -0,0 +1,90 @@ +/* + * pwd.c + * Implementation of SUSv3 XCU pwd utility + * Copyright © 2007 Rich Felker + * Licensed under the terms of the GNU General Public License, v2 or later + */ + +/* NOTE: This implementation assumes PATH_MAX is defined and correct. */ + +#include <limits.h> +#include <unistd.h> +#include <sys/stat.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> + +static int my_write(int fd, const char *s, size_t l) +{ + if (!l) l = strlen(s); + while (l) { + ssize_t n = write(fd, s, l); + if (n<0) return -1; + s += n; l -= n; + } + return 0; +} + +static void my_perror(char *prog, char *msg) +{ + char *err = strerror(errno); + write(2, prog, strlen(prog)); + write(2, ": ", 2); + write(2, msg, strlen(msg)); + write(2, ": ", 2); + write(2, err, strlen(err)); + write(2, "\n", 1); +} + +static int is_rel(const char *s) +{ + unsigned dots=0, slash=1; + if (*s++ != '/') return 1; + for (; *s; s++) { + if (*s == '/') { + if (dots-1<2) return 1; + dots=0; + } + else slash=1; + if (slash && *s == '.') dots++; + else dots=slash=0; + } + return dots-1<2; +} + +int main(int argc, char *argv[]) +{ + int i, j; + int p=0; + char buf[PATH_MAX+2]; + struct stat st1, st2; + char *pwd; + + for (i=1; i<argc && argv[i][0]=='-'; i++) + for (j=1; argv[i][j]; j++) { + switch (argv[i][j]) { + case 'L': p=0; continue; + case 'P': p=1; + case 0: continue; + } +invalid: + errno = EINVAL; + my_perror(argv[0], argv[i]); + return 1; + } + if (i<argc) goto invalid; + if (p || !(pwd=getenv("PWD")) || is_rel(pwd) + || stat(pwd, &st1) || stat(".", &st2) + || st1.st_dev != st2.st_dev + || st1.st_ino != st2.st_ino) { + if (!getcwd(buf, sizeof buf)) { + my_perror(argv[0], "getcwd"); + return 1; + } + } else { + /* safe because stat succeeded */ + strcpy(buf, pwd); + } + strcat(buf, "\n"); + return my_write(1, buf, 0) != 0; +} |