From 3f8c480969a513f8ecec3ad727ae4f9622f994f3 Mon Sep 17 00:00:00 2001 From: miod <> Date: Sun, 24 Jul 2011 21:03:00 +0000 Subject: [PATCH] Recent Single Unix will malloc memory if the second argument of realpath() is NULL, and third-party software is starting to rely upon this. Adapted from FreeBSD via Jona Joachim (jaj ; hcl-club , .lu), with minor tweaks from nicm@ and yours truly. --- src/lib/libc/stdlib/realpath.3 | 21 ++++++++++++--- src/lib/libc/stdlib/realpath.c | 48 +++++++++++++++++++++++++--------- 2 files changed, 52 insertions(+), 17 deletions(-) diff --git a/src/lib/libc/stdlib/realpath.3 b/src/lib/libc/stdlib/realpath.3 index c64fc3d6..fba88a6f 100644 --- a/src/lib/libc/stdlib/realpath.3 +++ b/src/lib/libc/stdlib/realpath.3 @@ -28,9 +28,9 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.\" $OpenBSD: realpath.3,v 1.15 2007/07/06 15:42:04 millert Exp $ +.\" $OpenBSD: realpath.3,v 1.16 2011/07/24 21:03:00 miod Exp $ .\" -.Dd $Mdocdate: July 6 2007 $ +.Dd $Mdocdate: July 24 2011 $ .Dt REALPATH 3 .Os .Sh NAME @@ -40,7 +40,7 @@ .Fd #include .Fd #include .Ft "char *" -.Fn realpath "const char *pathname" "char resolved[PATH_MAX]" +.Fn realpath "const char *pathname" "char *resolved" .Sh DESCRIPTION The .Fn realpath @@ -60,7 +60,8 @@ argument .Em must refer to a buffer capable of storing at least .Dv PATH_MAX -characters. +characters, or be +.Dv NULL . .Pp The .Fn realpath @@ -78,6 +79,13 @@ The function returns .Fa resolved on success. +If +.Fa resolved +is +.Dv NULL +and no error occured, then +.Fa realpath +returns a NUL-terminated string in a newly allocated buffer. If an error occurs, .Fn realpath returns @@ -98,6 +106,11 @@ and .Sh SEE ALSO .Xr readlink 1 , .Xr getcwd 3 +.Sh STANDARDS +The +.Fn realpath +function conforms to +.St -p1003.1-2008 . .Sh HISTORY The .Fn realpath diff --git a/src/lib/libc/stdlib/realpath.c b/src/lib/libc/stdlib/realpath.c index 4cb847b3..21af4cf0 100644 --- a/src/lib/libc/stdlib/realpath.c +++ b/src/lib/libc/stdlib/realpath.c @@ -1,4 +1,4 @@ -/* $OpenBSD: realpath.c,v 1.13 2005/08/08 08:05:37 espie Exp $ */ +/* $OpenBSD: realpath.c,v 1.14 2011/07/24 21:03:00 miod Exp $ */ /* * Copyright (c) 2003 Constantin S. Svintsoff * @@ -43,16 +43,30 @@ * in which case the path which caused trouble is left in (resolved). */ char * -realpath(const char *path, char resolved[PATH_MAX]) +realpath(const char *path, char *resolved) { struct stat sb; char *p, *q, *s; size_t left_len, resolved_len; unsigned symlinks; - int serrno, slen; + int serrno, slen, mem_allocated; char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX]; + if (path[0] == '\0') { + errno = ENOENT; + return (NULL); + } + serrno = errno; + + if (resolved == NULL) { + resolved = malloc(PATH_MAX); + if (resolved == NULL) + return (NULL); + mem_allocated = 1; + } else + mem_allocated = 0; + symlinks = 0; if (path[0] == '/') { resolved[0] = '/'; @@ -63,7 +77,10 @@ realpath(const char *path, char resolved[PATH_MAX]) left_len = strlcpy(left, path + 1, sizeof(left)); } else { if (getcwd(resolved, PATH_MAX) == NULL) { - strlcpy(resolved, ".", PATH_MAX); + if (mem_allocated) + free(resolved); + else + strlcpy(resolved, ".", PATH_MAX); return (NULL); } resolved_len = strlen(resolved); @@ -71,7 +88,7 @@ realpath(const char *path, char resolved[PATH_MAX]) } if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) { errno = ENAMETOOLONG; - return (NULL); + goto err; } /* @@ -86,7 +103,7 @@ realpath(const char *path, char resolved[PATH_MAX]) s = p ? p : left + left_len; if (s - left >= sizeof(next_token)) { errno = ENAMETOOLONG; - return (NULL); + goto err; } memcpy(next_token, left, s - left); next_token[s - left] = '\0'; @@ -96,7 +113,7 @@ realpath(const char *path, char resolved[PATH_MAX]) if (resolved[resolved_len - 1] != '/') { if (resolved_len + 1 >= PATH_MAX) { errno = ENAMETOOLONG; - return (NULL); + goto err; } resolved[resolved_len++] = '/'; resolved[resolved_len] = '\0'; @@ -127,23 +144,23 @@ realpath(const char *path, char resolved[PATH_MAX]) resolved_len = strlcat(resolved, next_token, PATH_MAX); if (resolved_len >= PATH_MAX) { errno = ENAMETOOLONG; - return (NULL); + goto err; } if (lstat(resolved, &sb) != 0) { if (errno == ENOENT && p == NULL) { errno = serrno; return (resolved); } - return (NULL); + goto err; } if (S_ISLNK(sb.st_mode)) { if (symlinks++ > MAXSYMLINKS) { errno = ELOOP; - return (NULL); + goto err; } slen = readlink(resolved, symlink, sizeof(symlink) - 1); if (slen < 0) - return (NULL); + goto err; symlink[slen] = '\0'; if (symlink[0] == '/') { resolved[1] = 0; @@ -165,7 +182,7 @@ realpath(const char *path, char resolved[PATH_MAX]) if (symlink[slen - 1] != '/') { if (slen + 1 >= sizeof(symlink)) { errno = ENAMETOOLONG; - return (NULL); + goto err; } symlink[slen] = '/'; symlink[slen + 1] = 0; @@ -173,7 +190,7 @@ realpath(const char *path, char resolved[PATH_MAX]) left_len = strlcat(symlink, left, sizeof(left)); if (left_len >= sizeof(left)) { errno = ENAMETOOLONG; - return (NULL); + goto err; } } left_len = strlcpy(left, symlink, sizeof(left)); @@ -187,4 +204,9 @@ realpath(const char *path, char resolved[PATH_MAX]) if (resolved_len > 1 && resolved[resolved_len - 1] == '/') resolved[resolved_len - 1] = '\0'; return (resolved); + +err: + if (mem_allocated) + free(resolved); + return (NULL); }