diff options
author | jilles <jilles@FreeBSD.org> | 2009-10-13 20:58:22 +0000 |
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committer | jilles <jilles@FreeBSD.org> | 2009-10-13 20:58:22 +0000 |
commit | 4fdff21cbb6547c80b57bdc57b4340925039ca59 (patch) | |
tree | d88be392af0fa3b5460b18eab99247fed63bc93b /lib/libc/gen/getcwd.c | |
parent | 58b36bef21f0fab5576a80af9fcb75c0a8c4928e (diff) | |
download | FreeBSD-src-4fdff21cbb6547c80b57bdc57b4340925039ca59.zip FreeBSD-src-4fdff21cbb6547c80b57bdc57b4340925039ca59.tar.gz |
Make getcwd(3) faster, simpler and more compliant using *at syscalls.
It is no longer necessary to construct long paths consisting of repeated
"../" which may be slow to process and may exceed PATH_MAX.
Diffstat (limited to 'lib/libc/gen/getcwd.c')
-rw-r--r-- | lib/libc/gen/getcwd.c | 63 |
1 files changed, 18 insertions, 45 deletions
diff --git a/lib/libc/gen/getcwd.c b/lib/libc/gen/getcwd.c index 0cd3208..c886dde 100644 --- a/lib/libc/gen/getcwd.c +++ b/lib/libc/gen/getcwd.c @@ -62,13 +62,14 @@ getcwd(pt, size) dev_t dev; ino_t ino; int first; - char *bpt, *bup; + char *bpt; struct stat s; dev_t root_dev; ino_t root_ino; - size_t ptsize, upsize; + size_t ptsize; int save_errno; - char *ept, *eup, *up, c; + char *ept, c; + int fd; /* * If no buffer specified by the user, allocate one as necessary. @@ -106,18 +107,6 @@ getcwd(pt, size) bpt = ept - 1; *bpt = '\0'; - /* - * Allocate 1024 bytes for the string of "../"'s. - * Should always be enough. If it's not, allocate - * as necessary. Special case the first stat, it's ".", not "..". - */ - if ((up = malloc(upsize = 1024)) == NULL) - goto err; - eup = up + upsize; - bup = up; - up[0] = '.'; - up[1] = '\0'; - /* Save root values, so know when to stop. */ if (stat("/", &s)) goto err; @@ -128,7 +117,7 @@ getcwd(pt, size) for (first = 1;; first = 0) { /* Stat the current level. */ - if (lstat(up, &s)) + if (dir != NULL ? _fstat(dirfd(dir), &s) : lstat(".", &s)) goto err; /* Save current node values. */ @@ -144,32 +133,22 @@ getcwd(pt, size) * been that way and stuff would probably break. */ bcopy(bpt, pt, ept - bpt); - free(up); + if (dir) + (void) closedir(dir); return (pt); } - /* - * Build pointer to the parent directory, allocating memory - * as necessary. Max length is 3 for "../", the largest - * possible component name, plus a trailing NUL. - */ - while (bup + 3 + MAXNAMLEN + 1 >= eup) { - if ((up = reallocf(up, upsize *= 2)) == NULL) - goto err; - bup = up; - eup = up + upsize; - } - *bup++ = '.'; - *bup++ = '.'; - *bup = '\0'; - /* Open and stat parent directory. */ - if (!(dir = opendir(up)) || _fstat(dirfd(dir), &s)) + fd = _openat(dir != NULL ? dirfd(dir) : AT_FDCWD, + "..", O_RDONLY); + if (fd == -1) goto err; - - /* Add trailing slash for next directory. */ - *bup++ = '/'; - *bup = '\0'; + if (dir) + (void) closedir(dir); + if (!(dir = fdopendir(fd)) || _fstat(dirfd(dir), &s)) { + _close(fd); + goto err; + } /* * If it's a mount point, have to stat each element because @@ -190,10 +169,10 @@ getcwd(pt, size) goto notfound; if (ISDOT(dp)) continue; - bcopy(dp->d_name, bup, dp->d_namlen + 1); /* Save the first error for later. */ - if (lstat(up, &s)) { + if (fstatat(dirfd(dir), dp->d_name, &s, + AT_SYMLINK_NOFOLLOW)) { if (!save_errno) save_errno = errno; errno = 0; @@ -227,11 +206,6 @@ getcwd(pt, size) *--bpt = '/'; bpt -= dp->d_namlen; bcopy(dp->d_name, bpt, dp->d_namlen); - (void) closedir(dir); - dir = NULL; - - /* Truncate any file name. */ - *bup = '\0'; } notfound: @@ -250,7 +224,6 @@ err: free(pt); if (dir) (void) closedir(dir); - free(up); errno = save_errno; return (NULL); |