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Prefer PATH_MAX to MAXPATHLEN

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PATH_MAX is standardized, MAXPATHLEN is not.
Also, the Gnulib pathmax module fixes some rare bugs with PATH_MAX.
So prefer PATH_MAX to MAXPATHLEN unless we know the latter is
also correct (for some platform-specific code).
* admin/merge-gnulib (GNULIB_MODULES): Add pathmax.
This module was already present, as a dependency of canonicalize-lgpl,
but now Emacs is using it directly.  Sort.
* lib-src/emacsclient.c: Include stdint.h, pathmax.h.
(get_current_dir_name): Sync to current src/sysdep.c.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* src/sysdep.c: Include pathmax.h.
(get_current_dir_name_or_unreachable):
Use PATH_MAX instead of MAXPATHLEN.
This commit is contained in:
Paul Eggert 2019-06-25 15:54:37 -07:00
parent 7dcefa7a2b
commit 824f784187
5 changed files with 26 additions and 25 deletions
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22
lib-src/emacsclient.c
View file

@ -74,6 +74,7 @@ char *w32_getenv (const char *);
#include <signal.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
@ -82,6 +83,7 @@ char *w32_getenv (const char *);
#include <dosname.h>
#include <intprops.h>
#include <min-max.h>
#include <pathmax.h>
#include <unlocked-io.h>
/* Work around GCC bug 88251. */
@ -238,6 +240,17 @@ char *get_current_dir_name (void);
char *
get_current_dir_name (void)
{
/* The maximum size of a directory name, including the terminating NUL.
Leave room so that the caller can append a trailing slash. */
ptrdiff_t dirsize_max = min (PTRDIFF_MAX, SIZE_MAX) - 1;
/* The maximum size of a buffer for a file name, including the
terminating NUL. This is bounded by PATH_MAX, if available. */
ptrdiff_t bufsize_max = dirsize_max;
#ifdef PATH_MAX
bufsize_max = min (bufsize_max, PATH_MAX);
#endif
char *buf;
struct stat dotstat, pwdstat;
/* If PWD is accurate, use it instead of calling getcwd. PWD is
@ -245,15 +258,12 @@ get_current_dir_name (void)
parent directory is searchable but not readable. */
char const *pwd = egetenv ("PWD");
if (pwd
&& (IS_DIRECTORY_SEP (*pwd) || (*pwd && IS_DEVICE_SEP (pwd[1])))
&& (pwdlen = strnlen (pwd, bufsize_max)) < bufsize_max
&& IS_DIRECTORY_SEP (pwd[pwdlen && IS_DEVICE_SEP (pwd[1]) ? 2 : 0])
&& stat (pwd, &pwdstat) == 0
&& stat (".", &dotstat) == 0
&& dotstat.st_ino == pwdstat.st_ino
&& dotstat.st_dev == pwdstat.st_dev
# ifdef MAXPATHLEN
&& strlen (pwd) < MAXPATHLEN
# endif
)
&& dotstat.st_dev == pwdstat.st_dev)
{
buf = xmalloc (strlen (pwd) + 1);
strcpy (buf, pwd);