From e24622787bc78f46045b83b9d39bbc08b46aba5e Mon Sep 17 00:00:00 2001 From: Keith Bostic Date: Wed, 20 Feb 1991 16:26:10 -0800 Subject: [PATCH] rename getwd to getcwd for POSIX.1 compatibility add System V, X/Open style path malloc'ing if user argument is NULL. SCCS-vsn: lib/libc/gen/getcwd.c 5.9 SCCS-vsn: lib/libc/gen/getcwd.3 6.3 --- usr/src/lib/libc/gen/getcwd.3 | 111 ++++++++++++++---- usr/src/lib/libc/gen/getcwd.c | 208 ++++++++++++++++++++++------------ 2 files changed, 227 insertions(+), 92 deletions(-) diff --git a/usr/src/lib/libc/gen/getcwd.3 b/usr/src/lib/libc/gen/getcwd.3 index 40243a75bb..a08d8ba192 100644 --- a/usr/src/lib/libc/gen/getcwd.3 +++ b/usr/src/lib/libc/gen/getcwd.3 @@ -1,29 +1,102 @@ -.\" Copyright (c) 1983 Regents of the University of California. -.\" All rights reserved. The Berkeley software License Agreement -.\" specifies the terms and conditions for redistribution. +.\" Copyright (c) 1991 The Regents of the University of California. +.\" All rights reserved. .\" -.\" @(#)getcwd.3 6.2 (Berkeley) %G% +.\" %sccs.include.redist.man% +.\" +.\" @(#)getcwd.3 6.3 (Berkeley) %G% .\" .TH GETWD 3 "" .UC 5 .SH NAME -getwd \- get current working directory pathname +getwd \- get working directory pathname .SH SYNOPSIS .nf -.B char *getwd(pathname) -.B char *pathname; +.ft B +char *getcwd(char *buf, size_t size); +char *getwd(char *buf); +.ft R .fi .SH DESCRIPTION +The +.I getcwd +function copies the absolute pathname of the current working directory +into the memory referenced by +.I buf +and returns a pointer to +.IR buf . +The +.I size +argument is the size, in bytes, of the array referenced by +.IR buf . +.PP +If +.I buf +is NULL, space is allocated as necessary to store the pathname. +This space may later be +.IR free 'd. +.PP +The function +.I getwd +is a compatibility routine which calls +.I getcwd +with its +.I buf +argument and a size of MAXPATHLEN (as defined in the include +file ). +Obviously, +.I buf +should be at least MAXPATHLEN bytes in length. +.PP +These routines have traditionally been used by programs to save the +name of a working directory for the purpose of returning to it. +A much faster and less error-prone method of accomplishing this is to +open the current directory (``.'') and use the +.IR fchdir (2) +function to return. +.SH RETURN VALUES +Upon successful completion, a pointer to the pathname is returned. +Otherwise a NULL pointer is returned and +.I errno +is set to indicate the error. +In addition, +.I getwd +copies the error message associated with +.I errno +into the memory referenced by +.IR buf . +.SH ERRORS +.I Getcwd +will fail if: +.TP 15 +[EACCESS] +Read or search permission was denied for a component of the pathname. +.TP 15 +[EINVAL] +The +.I size +argument is zero. +.TP 15 +[ENOENT] +A component of the pathname no longer exists. +.TP 15 +[ENOMEM] +Insufficient memory is available. +.TP 15 +[ERANGE] +The +.I size +argument is greater than zero but smaller than the length of the pathname +plus 1. +.SH BUGS .I Getwd -copies the absolute pathname of the current working directory to -.I pathname -and returns a pointer to the result. -.SH LIMITATIONS -Maximum pathname length is MAXPATHLEN characters (1024), -as defined in -.I . -.SH DIAGNOSTICS -.I Getwd -returns zero and places a message in -.I pathname -if an error occurs. +does not do sufficient error checking and is not able to return very +long, but valid, paths. +It is provided for compatibility. +.SH SEE ALSO +chdir(2), fchdir(2), malloc(3), strerror(3) +.SH STANDARDS +.I Getcwd +conforms to IEEE Std 1003.1-1988 (``POSIX''). +The ability to specify a NULL pointer and have +.I getcwd +allocate memory as necessary is an extension. diff --git a/usr/src/lib/libc/gen/getcwd.c b/usr/src/lib/libc/gen/getcwd.c index 1c5659f5e7..4e2519f964 100644 --- a/usr/src/lib/libc/gen/getcwd.c +++ b/usr/src/lib/libc/gen/getcwd.c @@ -1,17 +1,20 @@ /* - * Copyright (c) 1989 The Regents of the University of California. + * Copyright (c) 1989, 1991 The Regents of the University of California. * All rights reserved. * * %sccs.include.redist.c% */ #if defined(LIBC_SCCS) && !defined(lint) -static char sccsid[] = "@(#)getcwd.c 5.8 (Berkeley) %G%"; +static char sccsid[] = "@(#)getcwd.c 5.9 (Berkeley) %G%"; #endif /* LIBC_SCCS and not lint */ #include #include +#include #include +#include +#include #include #define ISDOT(dp) \ @@ -19,121 +22,180 @@ static char sccsid[] = "@(#)getcwd.c 5.8 (Berkeley) %G%"; dp->d_name[1] == '.' && dp->d_name[2] == '\0')) char * -getwd(store) - char *store; +getcwd(pt, size) + char *pt; + size_t size; { - extern int errno; register struct dirent *dp; register DIR *dir; + register dev_t dev; register ino_t ino; - register char *pp, *pu; register int first; + register char *bpt, *bup; struct stat s; - dev_t root_dev, dev; + dev_t root_dev; ino_t root_ino; - int save_errno, found; - char path[MAXPATHLEN], up[MAXPATHLEN], *file; + size_t ptsize, upsize; + int save_errno; + char *ept, *eup, *up; + + /* + * If no buffer specified by the user, allocate one as necessary. + * If a buffer is specified, the size has to be non-zero. The path + * is built from the end of the buffer backwards. + */ + if (pt) { + ptsize = 0; + if (!size) { + errno = EINVAL; + return((char *)NULL); + } + ept = pt + size; + } else { + if (!(pt = (char *)malloc(ptsize = 1024 - 4))) + return((char *)NULL); + ept = pt + ptsize; + } + bpt = ept - 1; + *ept = '\0'; + + /* + * Allocate bytes (1024 - malloc space) for the string of "../"'s. + * Should always be enough (it's 340 levels). If it's not, allocate + * as necessary. Special * case the first stat, it's ".", not "..". + */ + if (!(up = (char *)malloc(upsize = 1024 - 4))) + goto err; + eup = up + MAXPATHLEN; + bup = up; + up[0] = '.'; + up[1] = '\0'; - /* save root values */ - if (stat("/", &s)) { - file = "/"; + /* Save root values, so know when to stop. */ + if (stat("/", &s)) goto err; - } root_dev = s.st_dev; root_ino = s.st_ino; - /* init path pointer; built from the end of the buffer */ - pp = path + sizeof(path) - 1; - *pp = '\0'; + errno = 0; /* XXX readdir has no error return. */ - /* special case first stat, it's ".", not ".." */ - up[0] = '.'; - up[1] = '\0'; - - for (pu = up, first = 1;; first = 0) { - /* stat current level */ - if (lstat(up, &s)) { - file = up; + for (first = 1;; first = 0) { + /* Stat the current level. */ + if (lstat(up, &s)) goto err; - } - /* save current node values */ + /* Save current node values. */ ino = s.st_ino; dev = s.st_dev; - /* check for root */ + /* Check for reaching root. */ if (root_dev == dev && root_ino == ino) { - *store = '/'; - (void) strcpy(store + 1, pp); - return (store); + *--bpt = '/'; + /* + * It's unclear that it's a requirement to copy the + * path to the beginning of the buffer, but it's always + * been that way and stuff would probably break. + */ + (void)bcopy(bpt, pt, ept - bpt); + free(up); + return(pt); } - *pu++ = '.'; - *pu++ = '.'; - *pu = '\0'; + /* + * Build pointer to the parent directory, allocating memory + * as necessary. Max length is 3 for "../", the largest + * possible component name, plus a trailing NULL. + */ + if (bup + 3 + MAXNAMLEN + 1 >= eup) { + if (!(up = (char *)realloc(up, upsize *= 2))) + goto err; + eup = up + upsize; + } + *bup++ = '.'; + *bup++ = '.'; + *bup = '\0'; - /* open and stat parent */ - if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) { - file = up; + /* Open and stat parent directory. */ + if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) goto err; - } - found = save_errno = 0; - *pu++ = '/'; + /* Add trailing slash for next directory. */ + *bup++ = '/'; /* - * if it's a mount point you have to stat each element because + * If it's a mount point, have to stat each element because * the inode number in the directory is for the entry in the * parent directory, not the inode number of the mounted file. */ + save_errno = 0; if (s.st_dev == dev) { - while (dp = readdir(dir)) + for (;;) { + if (!(dp = readdir(dir))) + goto notfound; if (dp->d_fileno == ino) - goto hit; - } else { - while (dp = readdir(dir)) { + break; + } + } else + for (;;) { + if (!(dp = readdir(dir))) + goto notfound; if (ISDOT(dp)) continue; - bcopy(dp->d_name, pu, dp->d_namlen + 1); + bcopy(dp->d_name, bup, dp->d_namlen + 1); + + /* Save the first error for later. */ if (lstat(up, &s)) { - file = dp->d_name; - save_errno = errno; + if (!save_errno) + save_errno = errno; errno = 0; continue; } - if (s.st_dev == dev && s.st_ino == ino) { -hit: if (!first) - *--pp = '/'; - pp -= dp->d_namlen; - bcopy(dp->d_name, pp, dp->d_namlen); - found = 1; + if (s.st_dev == dev && s.st_ino == ino) break; - } - } - if (errno) { - file = up; - save_errno = errno; } - } - (void) closedir(dir); - *pu = '\0'; + /* + * Check for length of the current name, preceding slash, + * leading slash. + */ + if (bpt - pt <= dp->d_namlen + (first ? 1 : 2)) { + size_t len, off; - if (!found) { - /* - * We didn't find the current level in its parent - * directory; figure out what to complain about. - */ - if (save_errno) { - errno = save_errno; + if (!ptsize) { + errno = ERANGE; goto err; } - (void) sprintf(store, "%s not found in %s?\n", - first ? "." : pp, up); - return ((char *)NULL); + off = bpt - pt; + len = ept - bpt; + if (!(pt = (char *)realloc(pt, ptsize *= 2))) + goto err; + bpt = pt + off; + ept = pt + ptsize; + (void)bcopy(bpt, ept - len, len); + bpt = ept - len; } + if (!first) + *--bpt = '/'; + bpt -= dp->d_namlen; + bcopy(dp->d_name, bpt, dp->d_namlen); + (void)closedir(dir); + + /* Truncate any file name. */ + *bup = '\0'; } + +notfound: + /* + * If readdir set errno, use it, not any saved error; otherwise, + * didn't find the current directory in its parent directory, set + * errno to ENOENT. + */ + if (!errno) + errno = save_errno ? save_errno : ENOENT; + /* FALLTHROUGH */ err: - (void) sprintf(store, "getwd: %s: %s", file, strerror(errno)); - return ((char *)NULL); + if (ptsize) + free(pt); + free(up); + return((char *)NULL); } -- 2.20.1