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xrealloc_getcwd_or_warn: smaller cod and less wasted RAM at run time

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This commit is contained in:
Denis Vlasenko 2007-09-29 19:19:55 +00:00
parent 1ebd0a6d91
commit 2450e4ba44
1 changed files with 14 additions and 17 deletions
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31
libbb/xgetcwd.c
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@ -9,9 +9,6 @@
#include "libbb.h"
/* Amount to increase buffer size by in each try. */
#define PATH_INCR 32
/* Return the current directory, newly allocated, arbitrarily long.
Return NULL and set errno on error.
If argument is not NULL (previous usage allocate memory), call free()
@ -20,25 +17,25 @@
char *
xrealloc_getcwd_or_warn(char *cwd)
{
#define PATH_INCR 64
char *ret;
unsigned path_max;
path_max = (unsigned) PATH_MAX;
path_max += 2; /* The getcwd docs say to do this. */
path_max = 128; /* 128 + 64 should be enough for 99% of cases */
if (cwd == NULL)
cwd = xmalloc(path_max);
while ((ret = getcwd(cwd, path_max)) == NULL && errno == ERANGE) {
while (1) {
path_max += PATH_INCR;
cwd = xrealloc(cwd, path_max);
ret = getcwd(cwd, path_max);
if (ret == NULL) {
if (errno == ERANGE)
continue;
free(cwd);
bb_perror_msg("getcwd");
return NULL;
}
cwd = xrealloc(cwd, strlen(cwd) + 1);
return cwd;
}
if (ret == NULL) {
free(cwd);
bb_perror_msg("getcwd");
return NULL;
}
return cwd;
}