Define PATH_MAX if missing.

[DiamondLovesYou]

Summary

Some platforms lack any PATH_MAX definition. This defines PATH_MAX to a
sensibly large size in such cases.

Also, add one to PATH_MAX for the null byte.

[grosser]

This LGTM.

[Meinersbur]

lib/External/ppcg/cuda_common.c

23

From Linux' limits.h:

#define PATH_MAX        4096   /* # chars in a path name including nul */

I'd conclude that it is not necessary to reserve an additional char for the terminating nul.

lib/External/ppcg/ppcg.h

14

While maybe safe in practice, I don't think this is a good idea from a security/software quality perspective. But we can define PATH_MAX for platforms we know the the value of.

E.g. in lib/External/CMakeLists.txt we already have

if(MSVC)
  # In the Windows API (with some exceptions), the maximum length for a path is
  # MAX_PATH, which is defined as 260 characters.
  target_compile_definitions(PollyPPCG PRIVATE "-DPATH_MAX=260")
endif ()

[DiamondLovesYou]

Thanks for the comments, everyone. This was originally submitted to fix a rust-lang buildbot, which I've learned is based on CentOS 5.5 (yes). Anyhow, I've fixed the issue on that particular buildbot by defining PATH_MAX in C(XX)FLAGS. Thus this patch isn't needed anymore. Thanks again.

lib/External/ppcg/cpu.c

  * 'input' is the entire path of the input file. The output
  * is the file name plus the additional extension.
  *
  * We will basically replace everything after the last point
  * with '.ppcg.c'. This means file.c becomes file.ppcg.c
  */
 static FILE *get_output_file(const char *input, const char *output)
 {
-  char name[PATH_MAX];
+  char name[PATH_MAX + 1];
   const char *ext;
   const char ppcg_marker[] = ".ppcg";
   int len;
   FILE *file;
 
   len = ppcg_extract_base_name(name, input);
 
   strcpy(name + len, ppcg_marker);

lib/External/ppcg/cuda_common.c

 #include "cuda_common.h"
 #include "ppcg.h"
 
 /* Open the host .cu file and the kernel .hu and .cu files for writing.
  * Add the necessary includes.
  */
 void cuda_open_files(struct cuda_info *info, const char *input)
 {
-    char name[PATH_MAX];
+    char name[PATH_MAX + 1];
     int len;
 
     len = ppcg_extract_base_name(name, input);
 
     strcpy(name + len, "_host.cu");
     info->host_c = fopen(name, "w");
 
     strcpy(name + len, "_kernel.cu");

lib/External/ppcg/ppcg.h

 #ifndef PPCG_H
 #define PPCG_H
 
 #include <isl/schedule.h>
 #include <isl/set.h>
 #include <isl/union_set.h>
 #include <isl/union_map.h>
 #include <isl/id_to_ast_expr.h>
 #include <pet.h>
 
 #include "ppcg_options.h"
 
+#ifndef PATH_MAX
+#define PATH_MAX 4096
+#endif
+
 const char *ppcg_base_name(const char *filename);
 int ppcg_extract_base_name(char *name, const char *input);
 
 /* Representation of the scop for use inside PPCG.
  *
  * "options" are the options specified by the user.
  * Some fields in this structure may depend on some of the options.
  *