1e3e2ccd5
Denys Vlasenko
2017-07-25
Subject
ash: [SHELL] Optimize dash -c "command" to avoid a fork
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Architecture & Compiler Flags
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Build Log
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Commit Diff GitHub →
shell/ash.c+11 -7
| @@ -6128,7 +6128,9 @@ struct backcmd { /* result of evalbackcmd */ | |
| }; | |
| /* These forward decls are needed to use "eval" code for backticks handling: */ | |
| - | #define EV_EXIT 01 /* exit after evaluating tree */ |
| + | /* flags in argument to evaltree */ |
| + | #define EV_EXIT 01 /* exit after evaluating tree */ |
| + | #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ |
| static int evaltree(union node *, int); | |
| static void FAST_FUNC | |
| @@ -8345,10 +8347,6 @@ commandcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM) | |
| static void *funcblock; /* block to allocate function from */ | |
| static char *funcstring_end; /* end of block to allocate strings from */ | |
| - | /* flags in argument to evaltree */ |
| - | #define EV_EXIT 01 /* exit after evaluating tree */ |
| - | #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ |
| - | |
| static const uint8_t nodesize[N_NUMBER] ALIGN1 = { | |
| [NCMD ] = SHELL_ALIGN(sizeof(struct ncmd)), | |
| [NPIPE ] = SHELL_ALIGN(sizeof(struct npipe)), | |
| @@ -12491,6 +12489,12 @@ expandstr(const char *ps) | |
| return stackblock(); | |
| } | |
| + | static inline int |
| + | parser_eof(void) |
| + | { |
| + | return tokpushback && lasttoken == TEOF; |
| + | } |
| + | |
| /* | |
| * Execute a command or commands contained in a string. | |
| */ | |
| @@ -12526,7 +12530,7 @@ evalstring(char *s, int flags) | |
| while ((n = parsecmd(0)) != NODE_EOF) { | |
| int i; | |
| - | i = evaltree(n, flags); |
| + | i = evaltree(n, flags & ~(parser_eof() ? 0 : EV_EXIT)); |
| if (n) | |
| status = i; | |
| popstackmark(&smark); | |
| @@ -13671,7 +13675,7 @@ int ash_main(int argc UNUSED_PARAM, char **argv) | |
| // if (!sflag) g_parsefile->pf_fd = -1; | |
| // ^^ not necessary since now we special-case fd 0 | |
| // in is_hidden_fd() to not be considered "hidden fd" | |
| - | evalstring(minusc, 0); |
| + | evalstring(minusc, sflag ? 0 : EV_EXIT); |
| } | |
| if (sflag || minusc == NULL) { | |