46b494635
Denys Vlasenko
2016-04-03
Subject
libbb: speed up error_msg functions
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Commit Diff GitHub →
libbb/verror_msg.c+25 -4
| @@ -20,6 +20,7 @@ const char *msg_eol = "\n"; | |
| void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr) | |
| { | |
| char *msg, *msg1; | |
| + | char stack_msg[80]; |
| int applet_len, strerr_len, msgeol_len, used; | |
| if (!logmode) | |
| @@ -28,6 +29,27 @@ void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr) | |
| if (!s) /* nomsg[_and_die] uses NULL fmt */ | |
| s = ""; /* some libc don't like printf(NULL) */ | |
| + | applet_len = strlen(applet_name) + 2; /* "applet: " */ |
| + | strerr_len = strerr ? strlen(strerr) : 0; |
| + | msgeol_len = strlen(msg_eol); |
| + | |
| + | /* This costs ~90 bytes of code, but avoids costly |
| + | * malloc()[in vasprintf]+realloc()+memmove()+free() in 99% of cases. |
| + | * ~40% speedup. |
| + | */ |
| + | if ((int)sizeof(stack_msg) - applet_len > 0) { |
| + | va_list p2; |
| + | |
| + | /* It is not portable to use va_list twice, need to va_copy it */ |
| + | va_copy(p2, p); |
| + | used = vsnprintf(stack_msg + applet_len, (int)sizeof(stack_msg) - applet_len, s, p2); |
| + | va_end(p2); |
| + | msg = stack_msg; |
| + | used += applet_len; |
| + | if (used < (int)sizeof(stack_msg) - 3 - msgeol_len - strerr_len) |
| + | goto add_pfx_and_sfx; |
| + | } |
| + | |
| used = vasprintf(&msg, s, p); | |
| if (used < 0) | |
| return; | |
| @@ -37,9 +59,6 @@ void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr) | |
| * This is needed for e.g. httpd logging, when multiple | |
| * children can produce log messages simultaneously. */ | |
| - | applet_len = strlen(applet_name) + 2; /* "applet: " */ |
| - | strerr_len = strerr ? strlen(strerr) : 0; |
| - | msgeol_len = strlen(msg_eol); |
| /* can't use xrealloc: it calls error_msg on failure, | |
| * that may result in a recursion */ | |
| /* +3 is for ": " before strerr and for terminating NUL */ | |
| @@ -52,6 +71,7 @@ void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr) | |
| /* TODO: maybe use writev instead of memmoving? Need full_writev? */ | |
| memmove(msg + applet_len, msg, used); | |
| used += applet_len; | |
| + | add_pfx_and_sfx: |
| strcpy(msg, applet_name); | |
| msg[applet_len - 2] = ':'; | |
| msg[applet_len - 1] = ' '; | |
| @@ -76,7 +96,8 @@ void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr) | |
| syslog(syslog_level, "%s", msg + applet_len); | |
| } | |
| #endif | |
| - | free(msg); |
| + | if (msg != stack_msg) |
| + | free(msg); |
| } | |
| #ifdef VERSION_WITH_WRITEV | |