| 1 | #include <sys/select.h> |
| 2 | #include <stdlib.h> |
| 3 | #include <stdio.h> |
| 4 | #include <string.h> |
| 5 | #include <signal.h> |
| 6 | #include "pager.h" |
| 7 | #include "run-command.h" |
| 8 | #include "sigchain.h" |
| 9 | #include "subcmd-config.h" |
| 10 | |
| 11 | /* |
| 12 | * This is split up from the rest of git so that we can do |
| 13 | * something different on Windows. |
| 14 | */ |
| 15 | |
| 16 | static int spawned_pager; |
| 17 | |
| 18 | void pager_init(const char *pager_env) |
| 19 | { |
| 20 | subcmd_config.pager_env = pager_env; |
| 21 | } |
| 22 | |
| 23 | static void pager_preexec(void) |
| 24 | { |
| 25 | /* |
| 26 | * Work around bug in "less" by not starting it until we |
| 27 | * have real input |
| 28 | */ |
| 29 | fd_set in; |
| 30 | |
| 31 | FD_ZERO(&in); |
| 32 | FD_SET(0, &in); |
| 33 | select(1, &in, NULL, &in, NULL); |
| 34 | |
| 35 | setenv("LESS", "FRSX", 0); |
| 36 | } |
| 37 | |
| 38 | static const char *pager_argv[] = { "sh", "-c", NULL, NULL }; |
| 39 | static struct child_process pager_process; |
| 40 | |
| 41 | static void wait_for_pager(void) |
| 42 | { |
| 43 | fflush(stdout); |
| 44 | fflush(stderr); |
| 45 | /* signal EOF to pager */ |
| 46 | close(1); |
| 47 | close(2); |
| 48 | finish_command(&pager_process); |
| 49 | } |
| 50 | |
| 51 | static void wait_for_pager_signal(int signo) |
| 52 | { |
| 53 | wait_for_pager(); |
| 54 | sigchain_pop(signo); |
| 55 | raise(signo); |
| 56 | } |
| 57 | |
| 58 | void setup_pager(void) |
| 59 | { |
| 60 | const char *pager = getenv(subcmd_config.pager_env); |
| 61 | |
| 62 | if (!isatty(1)) |
| 63 | return; |
| 64 | if (!pager) |
| 65 | pager = getenv("PAGER"); |
| 66 | if (!(pager || access("/usr/bin/pager", X_OK))) |
| 67 | pager = "/usr/bin/pager"; |
| 68 | if (!(pager || access("/usr/bin/less", X_OK))) |
| 69 | pager = "/usr/bin/less"; |
| 70 | if (!pager) |
| 71 | pager = "cat"; |
| 72 | if (!*pager || !strcmp(pager, "cat")) |
| 73 | return; |
| 74 | |
| 75 | spawned_pager = 1; /* means we are emitting to terminal */ |
| 76 | |
| 77 | /* spawn the pager */ |
| 78 | pager_argv[2] = pager; |
| 79 | pager_process.argv = pager_argv; |
| 80 | pager_process.in = -1; |
| 81 | pager_process.preexec_cb = pager_preexec; |
| 82 | |
| 83 | if (start_command(&pager_process)) |
| 84 | return; |
| 85 | |
| 86 | /* original process continues, but writes to the pipe */ |
| 87 | dup2(pager_process.in, 1); |
| 88 | if (isatty(2)) |
| 89 | dup2(pager_process.in, 2); |
| 90 | close(pager_process.in); |
| 91 | |
| 92 | /* this makes sure that the parent terminates after the pager */ |
| 93 | sigchain_push_common(wait_for_pager_signal); |
| 94 | atexit(wait_for_pager); |
| 95 | } |
| 96 | |
| 97 | int pager_in_use(void) |
| 98 | { |
| 99 | return spawned_pager; |
| 100 | } |