From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 26 Jul 2004 15:43:57 +0000 (+0000)
Subject: Added some comments.
X-Git-Tag: svn/VALGRIND_2_2_0~105
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4421ac53b708b420ae99d9b855d4682c4e09ac48;p=thirdparty%2Fvalgrind.git

Added some comments.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@2531
---

diff --git a/coregrind/ume.c b/coregrind/ume.c
index c0bdb0a8b1..89ffe8e05d 100644
--- a/coregrind/ume.c
+++ b/coregrind/ume.c
@@ -667,6 +667,8 @@ static int do_exec_inner(const char *exe, struct exeinfo *info)
    return ret;
 }
 
+// See ume.h for an indication of which entries of 'info' are inputs, which
+// are outputs, and which are both.
 int do_exec(const char *exe, struct exeinfo *info)
 {
    info->interp_name = NULL;
diff --git a/coregrind/ume.h b/coregrind/ume.h
index 70008e1815..1155edecda 100644
--- a/coregrind/ume.h
+++ b/coregrind/ume.h
@@ -54,26 +54,32 @@ typedef ESZ(Addr) addr_t;
 /*--- Loading ELF files                                    ---*/
 /*------------------------------------------------------------*/
 
+// Info needed to load and run a program.  IN/INOUT/OUT refers to the
+// inputs/outputs of do_exec().
 struct exeinfo
 {
-   addr_t map_base;     // INPUT: if non-zero, base address of mappings
-   char** argv;         // INPUT: the original argv
+   addr_t map_base;     // IN: if non-zero, base address of mappings
+   char** argv;         // IN: the original argv
 
    addr_t exe_base;     // INOUT: lowest (allowed) address of exe
    addr_t exe_end;      // INOUT: highest (allowed) address
 
-   addr_t phdr;         // address phdr was mapped at
-   int    phnum;        // number of phdrs
-   addr_t interp_base;  // where interpreter (ld.so) was mapped
-   addr_t entry;        // entrypoint in main executable
-   addr_t init_eip;     // initial eip
-   addr_t brkbase;      // base address of brk segment
+   addr_t phdr;         // OUT: address phdr was mapped at
+   int    phnum;        // OUT: number of phdrs
+   addr_t interp_base;  // OUT: where interpreter (ld.so) was mapped
+   addr_t entry;        // OUT: entrypoint in main executable
+   addr_t init_eip;     // OUT: initial eip
+   addr_t brkbase;      // OUT: base address of brk segment
 
    // These are the extra args added by #! scripts
-   char*  interp_name;  // INPUT: the interpreter name
-   char*  interp_args;  // INPUT: the args for the interpreter
+   char*  interp_name;  // OUT: the interpreter name
+   char*  interp_args;  // OUT: the args for the interpreter
 };
 
+// Does everything short of actually running 'exe': finds the file,
+// checks execute permissions, sets up interpreter if program is a script, 
+// reads headers, maps file into memory, and returns important info about
+// the program.
 int do_exec(const char *exe, struct exeinfo *info);
 
 /*------------------------------------------------------------*/
@@ -84,6 +90,7 @@ void foreach_map(int (*fn)(void *start, void *end,
 			   const char *perm, off_t offset,
 			   int maj, int min, int ino));
 
+// Padding functions used at startup to force things where we want them.
 void as_pad(void *start, void *end);
 void as_unpad(void *start, void *end);
 void as_closepadfile(void);
diff --git a/coregrind/vg_main.c b/coregrind/vg_main.c
index f3470c5516..c3f45232e3 100644
--- a/coregrind/vg_main.c
+++ b/coregrind/vg_main.c
@@ -1445,13 +1445,13 @@ static void load_client(char* cl_argv[], const char* exec, Int need_help,
    }
 
    info->map_base = VG_(client_mapbase);
-
    info->exe_base = VG_(client_base);
    info->exe_end  = VG_(client_end);
    info->argv     = cl_argv;
 
    if (need_help) {
       VG_(clexecfd) = -1;
+      // Set the minimal number of entries in 'info' to continue.
       info->interp_name = NULL;
       info->interp_args = NULL;
    } else {
@@ -1459,7 +1459,8 @@ static void load_client(char* cl_argv[], const char* exec, Int need_help,
       VG_(clexecfd) = VG_(open)(exec, O_RDONLY, VKI_S_IRUSR);
       ret = do_exec(exec, info);
       if (ret != 0) {
-         fprintf(stderr, "valgrind: do_exec(%s) failed: %s\n", exec, strerror(ret));
+         fprintf(stderr, "valgrind: do_exec(%s) failed: %s\n",
+                         exec, strerror(ret));
          exit(127);
       }
    }