child_spawn.c (1525B)
1 /* ISC license. */ 2 3 #include <string.h> 4 #include <unistd.h> 5 6 #include <skalibs/types.h> 7 #include <skalibs/djbunix.h> 8 #include <skalibs/env.h> 9 #include <skalibs/cspawn.h> 10 11 pid_t child_spawn (char const *prog, char const *const *argv, char const *const *envp, int *fds, size_t n) 12 { 13 pid_t pid ; 14 cspawn_fileaction fa[2] = 15 { 16 [0] = { .type = CSPAWN_FA_MOVE, .x = { .fd2 = { [0] = 1 } } }, 17 [1] = { .type = CSPAWN_FA_MOVE, .x = { .fd2 = { [0] = 0 } } } 18 } ; 19 size_t m = sizeof(SKALIBS_CHILD_SPAWN_FDS_ENVVAR) ; 20 size_t envlen = env_len(envp) ; 21 size_t i = 0 ; 22 int p[n ? n : 1][2] ; 23 char const *newenv[envlen + 2] ; 24 char modifs[m + 1 + n * UINT_FMT] ; 25 26 for (; i < n ; i++) 27 { 28 if (pipe(p[i]) == -1) goto errpi ; 29 if ((ndelay_on(p[i][i & 1]) == -1) || (coe(p[i][i & 1]) == -1)) goto errpip ; 30 } 31 32 memcpy(modifs, SKALIBS_CHILD_SPAWN_FDS_ENVVAR "=", sizeof(SKALIBS_CHILD_SPAWN_FDS_ENVVAR)) ; 33 for (i = 2 ; i < n ; i++) 34 { 35 m += uint_fmt(modifs + m, p[i][!(i & 1)]) ; 36 if (i+1 < n) modifs[m++] = ',' ; 37 } 38 modifs[m++] = 0 ; 39 env_mergen(newenv, envlen + 2, envp, envlen, modifs, m, 1) ; 40 if (n) fa[0].x.fd2[1] = p[0][1] ; 41 if (n >= 2) fa[1].x.fd2[1] = p[1][0] ; 42 pid = cspawn(prog, argv, newenv, CSPAWN_FLAGS_SIGBLOCKNONE, fa, n < 2 ? n : 2) ; 43 if (!pid) goto errpi ; 44 45 for (i = 0 ; i < n ; i++) 46 { 47 fd_close(p[i][!(i & 1)]) ; 48 fds[i] = p[i][i & 1] ; 49 } 50 return pid ; 51 52 errpip: 53 i++ ; 54 errpi: 55 while (i--) 56 { 57 fd_close(p[i][1]) ; 58 fd_close(p[i][0]) ; 59 } 60 return 0 ; 61 }