diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/getcwd.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/getcwd.c | 59 |
1 files changed, 56 insertions, 3 deletions
diff --git a/sysdeps/unix/sysv/linux/getcwd.c b/sysdeps/unix/sysv/linux/getcwd.c index ed649f8fef..0bf9a9fb0e 100644 --- a/sysdeps/unix/sysv/linux/getcwd.c +++ b/sysdeps/unix/sysv/linux/getcwd.c @@ -1,5 +1,5 @@ /* Determine current working directory. Linux version. - Copyright (C) 1997 Free Software Foundation, Inc. + Copyright (C) 1997, 1998 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. @@ -22,6 +22,7 @@ #include <limits.h> #include <stdlib.h> #include <unistd.h> +#include <sys/syscall.h> /* The "proc" filesystem provides an easy method to retrieve the value. @@ -31,10 +32,20 @@ the proc filesystem mounted. Use the POSIX implementation in this case. */ static char *generic_getcwd (char *buf, size_t size) internal_function; +#ifdef __NR_getcwd +/* Kernel 2.1.92 introduced a third way to get the current working + directory: a syscall. We've got to be careful that even when + compiling under 2.1.92+ the libc still runs under older kernels. */ +extern int __syscall_getcwd (char *buf, unsigned long size); +static no_syscall_getcwd; +static int no_new_dcache = 1; +#else +static int no_new_dcache; +#endif + char * __getcwd (char *buf, size_t size) { - static int no_new_dcache = 0; int save_errno; char *path; int n; @@ -66,6 +77,41 @@ __getcwd (char *buf, size_t size) save_errno = errno; +#ifdef __NR_getcwd + if (!no_syscall_getcwd) + { + int retval; + + do + retval = __syscall_getcwd (path, alloc_size); + if (retval >= 0) + { + if (buf == NULL) + { + buf = realloc (path, strlen (path) + 1); + if (buf == NULL) + /* `relloc' failed but we still have the original string. */ + buf = path; + } + return buf; + } + + if (errno == ENOSYS) + { + no_syscall_getcwd = 1; + no_new_dcache = 0; /* Now we will try the /proc method. */ + } + else if (errno != ERANGE || buf != NULL) + { + if (buf == NULL) + free (path); + return NULL; + } + + __set_errno (save_errno); + } +#endif + n = __readlink ("/proc/self/cwd", path, alloc_size - 1); if (n != -1) { @@ -79,7 +125,14 @@ __getcwd (char *buf, size_t size) } path[n] = '\0'; - return buf ?: (char *) realloc (path, (size_t) n + 1); + if (buf == NULL) + { + buf = realloc (path, (size_t) n + 1); + if (buf == NULL) + /* `relloc' failed but we still have the original string. */ + buf = path; + } + return buf; } else no_new_dcache = 1; |