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Remove the buffer argument from loc_getenv
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1.Avoid to allocate the big buffer on the caller stack
2.The temporary buffer is only used on cygwin

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I8bd325624a2f9b8cd1f791f0c07fc76d02158e1d
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@xiaoxiang781216
xiaoxiang781216 committed Jun 28, 2021
1 parent 95ae7d7 commit 056ea22
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Showing 5 changed files with 47 additions and 31 deletions.
18 changes: 10 additions & 8 deletions compat.c
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Original file line number Diff line number Diff line change
Expand Up @@ -468,14 +468,16 @@ char *strsep(char **string_p, const char *delim)
/*
* Local getenv which handles some portability stuff.
*/
char *loc_getenv(const char *var, char *buf, const int buf_size,
const int stay_safe)
{
#undef loc_getenv
#if defined(__CYGWIN__) && HAVE_GETENVIRONMENTVARIABLEA
/* use this function instead of getenv */
GetEnvironmentVariableA(var, buf, buf_size);
return buf;
#else /* ! __CYGWIN__ */
char *loc_getenv(const char *var, char *buf, const int buf_size)
{
int ret = GetEnvironmentVariableA(var, buf, buf_size);
return ret > 0 && ret < buf_size ? buf : NULL;
}
#else
char *loc_getenv(const char *var, const int stay_safe)
{
#if GETENV_SAFE == 0
if (stay_safe) {
/* oh, well. no idea how to get the environmental variables */
Expand All @@ -484,5 +486,5 @@ char *loc_getenv(const char *var, char *buf, const int buf_size,
#endif /* GETENV_SAFE == 0 */
/* get the options flag */
return getenv(var);
#endif /* ! __CYGWIN__ */
}
#endif /* ! __CYGWIN__ */
15 changes: 13 additions & 2 deletions compat.h
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Original file line number Diff line number Diff line change
Expand Up @@ -200,9 +200,20 @@ char *strsep(char **string_p, const char *delim);
/*
* Local getenv which handles some portability stuff.
*/
#if defined(__CYGWIN__) && HAVE_GETENVIRONMENTVARIABLEA
extern
char *loc_getenv(const char *var, char *buf, const int buf_size,
const int stay_safe);
char *loc_getenv(const char *var, char *buf, const int buf_size);

#define loc_getenv(var, stay_safe, val) \
char buf##__LINE__[256]; \
*(val) = loc_getenv(var, buf##__LINE__, sizeof(buf##__LINE__))
#else
extern
char *loc_getenv(const char *var, const int stay_safe);

#define loc_getenv(var, stay_safe, val) \
*(val) = loc_getenv(var, stay_safe)
#endif /* ! __CYGWIN__ */

/*<<<<<<<<<< This is end of the auto-generated output from fillproto. */

Expand Down
15 changes: 5 additions & 10 deletions dmalloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -227,9 +227,8 @@ static void choose_shell(void)
{
const char *shell, *shell_p;
int shell_c;
char env_buf[256];

shell = loc_getenv(SHELL_ENVIRON, env_buf, sizeof(env_buf), 0);
loc_getenv(SHELL_ENVIRON, 0, &shell);
if (shell == NULL) {
/* oh well, we just guess on c-shell */
cshell_b = 1;
Expand Down Expand Up @@ -504,7 +503,6 @@ static long find_tag(const long debug_value, const char *tag_find,
const char *home_p;
int ret;
long new_debug = 0;
char env_buf[256];

/* do we need to have a home variable? */
if (inpath == NULL) {
Expand All @@ -523,7 +521,7 @@ static long find_tag(const long debug_value, const char *tag_find,
}
else {
/* find our home directory */
home_p = loc_getenv(HOME_ENVIRON, env_buf, sizeof(env_buf), 0);
loc_getenv(HOME_ENVIRON, 0, &home_p);
if (home_p == NULL) {
loc_fprintf(stderr, "%s: could not find variable '%s'\n",
argv_program, HOME_ENVIRON);
Expand Down Expand Up @@ -620,7 +618,6 @@ static void list_tags(void)
const char *home_p;
long new_debug = 0;
FILE *rc_file;
char env_buf[256];

/* do we need to have a home variable? */
if (inpath == NULL) {
Expand All @@ -630,7 +627,7 @@ static void list_tags(void)
if (rc_file == NULL) {

/* if no file in current directory, try home directory */
home_p = loc_getenv(HOME_ENVIRON, env_buf, sizeof(env_buf), 0);
loc_getenv(HOME_ENVIRON, 0, &home_p);
if (home_p == NULL) {
loc_fprintf(stderr, "%s: could not find variable '%s'\n",
argv_program, HOME_ENVIRON);
Expand Down Expand Up @@ -703,10 +700,9 @@ static void dump_current(void)
unsigned long addr_count;
int lock_on, loc_start_line;
unsigned int flags;
char env_buf[256];

/* get the options flag */
env_str = loc_getenv(OPTIONS_ENVIRON, env_buf, sizeof(env_buf), 0);
loc_getenv(OPTIONS_ENVIRON, 0, &env_str);
if (env_str == NULL) {
env_str = "";
}
Expand Down Expand Up @@ -858,7 +854,6 @@ int main(int argc, char **argv)
int lock_on;
int loc_start_line;
unsigned int flags;
char env_buf[256];

argv_help_string = "Sets dmalloc library env variables. Also try --usage.";
argv_version_string = dmalloc_version;
Expand Down Expand Up @@ -897,7 +892,7 @@ int main(int argc, char **argv)
}

/* get the current debug information from the env variable */
env_str = loc_getenv(OPTIONS_ENVIRON, env_buf, sizeof(env_buf), 0);
loc_getenv(OPTIONS_ENVIRON, 0, &env_str);
if (env_str == NULL) {
env_str = "";
}
Expand Down
6 changes: 2 additions & 4 deletions dmalloc_argv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2710,7 +2710,6 @@ static int do_env_args(argv_t *args, argv_t **queue_list,
{
int env_c, env_n;
char **vect_p, env_name[256], *environ_p;
char env_buf[256];

/* create the env variable */
(void)loc_snprintf(env_name, sizeof(env_name), ENVIRON_FORMAT, argv_program);
Expand All @@ -2722,7 +2721,7 @@ static int do_env_args(argv_t *args, argv_t **queue_list,
}
}

environ_p = loc_getenv(env_name, env_buf, sizeof(env_buf), 0);
loc_getenv(env_name, 0, &environ_p);
if (environ_p == NULL) {
return NOERROR;
}
Expand Down Expand Up @@ -2761,7 +2760,6 @@ static int process_env(void)
static int done_b = ARGV_FALSE;
char *env_val, *tok_p, *env_p;
int len;
char env_buf[256];

/* make sure we only do this once */
if (done_b) {
Expand All @@ -2771,7 +2769,7 @@ static int process_env(void)
done_b = ARGV_TRUE;

/* get the argv information */
env_val = loc_getenv(GLOBAL_NAME, env_buf, sizeof(env_buf), 0);
loc_getenv(GLOBAL_NAME, 0, &env_val);
if (env_val == NULL) {
return NOERROR;
}
Expand Down
24 changes: 17 additions & 7 deletions user_malloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -337,7 +337,6 @@ static int dmalloc_startup(const char *debug_str)
{
static int some_up_b = 0;
const char *env_str;
char env_buf[256];

/* have we started already? */
if (enabled_b) {
Expand All @@ -356,15 +355,14 @@ static int dmalloc_startup(const char *debug_str)
#endif
#endif

/* process the environmental variable(s) */
if (debug_str == NULL) {
env_str = loc_getenv(OPTIONS_ENVIRON, env_buf, sizeof(env_buf),
1 /* stay safe */);
loc_getenv(OPTIONS_ENVIRON, 1 /* stay safe */, &env_str);
process_environ(env_str);
}
else {
env_str = debug_str;
process_environ(debug_str);
}
/* process the environmental variable(s) */
process_environ(env_str);

/*
* Tune the environment here. If we have a start-file,
Expand Down Expand Up @@ -1516,10 +1514,22 @@ unsigned int dmalloc_debug_current(void)
*/
char *dmalloc_debug_current_env(char *env_buf, const int env_buf_size)
{
const char *env_str;

if (! enabled_b) {
(void)dmalloc_startup(NULL /* no options string */);
}
return loc_getenv(OPTIONS_ENVIRON, env_buf, env_buf_size, 0);

loc_getenv(OPTIONS_ENVIRON, 0, &env_str);
if (env_str) {
strncpy(env_buf, env_str, env_buf_size);
env_buf[env_buf_size - 1] = '\0';
}
else {
env_buf[0] = '\0';
}

return env_buf;
}

/*
Expand Down

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