--- miniexpect.c | 41 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 2 deletions(-) diff --git a/miniexpect.c b/miniexpect.c index d5a7c6e..d2ceb69 100644 --- a/miniexpect.c +++ b/miniexpect.c @@ -22,6 +22,7 @@ #include <stdlib.h> #include <stdarg.h> #include <string.h> +#include <ctype.h> #include <fcntl.h> #include <unistd.h> #include <signal.h> @@ -47,6 +48,10 @@ #define DEBUG 0 +#if DEBUG +static void debug_buffer (FILE *, char *); +#endif + static mexp_h * create_handle (void) { @@ -333,7 +338,9 @@ mexp_expect (mexp_h *h, const mexp_regexp *regexps, int *ovector, int ovecsize) h->buffer[h->len] = '\0'; #if DEBUG fprintf (stderr, "DEBUG: read %zd bytes from pty\n", rs); - fprintf (stderr, "DEBUG: buffer content: %s\n", h->buffer); + fprintf (stderr, "DEBUG: buffer content: "); + debug_buffer (stderr, h->buffer); + fprintf (stderr, "\n"); #endif try_match: @@ -406,7 +413,9 @@ mexp_printf (mexp_h *h, const char *fs, ...) return -1; #if DEBUG - fprintf (stderr, "DEBUG: writing: %s\n", msg); + fprintf (stderr, "DEBUG: writing: "); + debug_buffer (stderr, msg); + fprintf (stderr, "\n"); #endif n = len; @@ -430,3 +439,31 @@ mexp_send_interrupt (mexp_h *h) { return write (h->fd, "\003", 1); } + +#if DEBUG +/* Print escaped buffer to fp. */ +static void +debug_buffer (FILE *fp, char *buf) +{ + while (*buf) { + if (isprint (*buf)) + fputc (*buf, fp); + else { + switch (*buf) { + case '\0': fputs ("\\0", fp); break; + case '\a': fputs ("\\a", fp); break; + case '\b': fputs ("\\b", fp); break; + case '\f': fputs ("\\f", fp); break; + case '\n': fputs ("\\n", fp); break; + case '\r': fputs ("\\r", fp); break; + case '\t': fputs ("\\t", fp); break; + case '\v': fputs ("\\v", fp); break; + default: + fprintf (fp, "\\x%x", (unsigned char) *buf); + } + } + buf++; + } +} +#endif + -- 2.13.2

Debugging can now be enabled at runtime. --- example-sshpass.c | 46 +++++++++++++++++++++++++------- miniexpect.c | 78 ++++++++++++++++++++++++++++++++++--------------------- miniexpect.h | 6 +++++ miniexpect.pod | 21 +++++++++++++++ 4 files changed, 113 insertions(+), 38 deletions(-) diff --git a/example-sshpass.c b/example-sshpass.c index 3449a20..11df02e 100644 --- a/example-sshpass.c +++ b/example-sshpass.c @@ -24,8 +24,10 @@ * The remaining arguments are passed to the ssh subprocess. * * For example: - * sshpass 123456 ssh remote.example.com - * sshpass 123456 ssh -l root remote.example.com + * sshpass [-d] 123456 ssh remote.example.com + * sshpass [-d] 123456 ssh -l root remote.example.com + * + * Use the -d flag to enable debugging to stderr. */ #include <config.h> @@ -42,9 +44,18 @@ static pcre *compile_re (const char *rex); +static void +usage (void) +{ + fprintf (stderr, "usage: sshpass PASSWORD ssh [SSH-ARGS...] HOST\n"); + exit (EXIT_FAILURE); +} + int main (int argc, char *argv[]) { + int opt; + int debug = 0; mexp_h *h; const char *password; int status; @@ -52,20 +63,31 @@ main (int argc, char *argv[]) const int ovecsize = 12; int ovector[ovecsize]; - if (argc <= 3) { - fprintf (stderr, "usage: sshpass PASSWORD ssh [SSH-ARGS...] HOST\n"); - exit (EXIT_FAILURE); + while ((opt = getopt (argc, argv, "d")) != -1) { + switch (opt) { + case 'd': + debug = 1; + break; + default: + usage (); + } } - password = argv[1]; + if (argc-optind <= 2) + usage (); + + password = argv[optind]; + optind++; printf ("starting ssh command ...\n"); - h = mexp_spawnv (argv[2], &argv[2]); + h = mexp_spawnv (argv[optind], &argv[optind]); if (h == NULL) { perror ("mexp_spawnv: ssh"); exit (EXIT_FAILURE); } + if (debug) + mexp_set_debug_file (h, stderr); /* Wait for the password prompt. */ password_re = compile_re ("assword"); @@ -91,10 +113,16 @@ main (int argc, char *argv[]) goto error; } - /* Got the password prompt, so send a password. */ + /* Got the password prompt, so send a password. + * + * Note use of mexp_printf_password here which is identical to + * mexp_printf except that it hides the password in debugging + * output. + */ printf ("sending the password ...\n"); - if (mexp_printf (h, "%s\n", password) == -1) { + if (mexp_printf_password (h, "%s", password) == -1 || + mexp_printf (h, "\n") == -1) { perror ("mexp_printf"); goto error; } diff --git a/miniexpect.c b/miniexpect.c index d2ceb69..1ac373b 100644 --- a/miniexpect.c +++ b/miniexpect.c @@ -46,11 +46,7 @@ #include "miniexpect.h" -#define DEBUG 0 - -#if DEBUG static void debug_buffer (FILE *, char *); -#endif static mexp_h * create_handle (void) @@ -68,6 +64,7 @@ create_handle (void) h->buffer = NULL; h->len = h->alloc = 0; h->next_match = -1; + h->debug_fp = NULL; h->user1 = h->user2 = h->user3 = NULL; return h; @@ -296,9 +293,8 @@ mexp_expect (mexp_h *h, const mexp_regexp *regexps, int *ovector, int ovecsize) pfds[0].events = POLLIN; pfds[0].revents = 0; r = poll (pfds, 1, timeout); -#if DEBUG - fprintf (stderr, "DEBUG: poll returned %d\n", r); -#endif + if (h->debug_fp) + fprintf (h->debug_fp, "DEBUG: poll returned %d\n", r); if (r == -1) return MEXP_ERROR; @@ -318,9 +314,8 @@ mexp_expect (mexp_h *h, const mexp_regexp *regexps, int *ovector, int ovecsize) h->alloc += h->read_size; } rs = read (h->fd, h->buffer + h->len, h->read_size); -#if DEBUG - fprintf (stderr, "DEBUG: read returned %zd\n", rs); -#endif + if (h->debug_fp) + fprintf (h->debug_fp, "DEBUG: read returned %zd\n", rs); if (rs == -1) { /* Annoyingly on Linux (I'm fairly sure this is a bug) if the * writer closes the connection, the entire pty is destroyed, @@ -336,12 +331,12 @@ mexp_expect (mexp_h *h, const mexp_regexp *regexps, int *ovector, int ovecsize) /* We read something. */ h->len += rs; h->buffer[h->len] = '\0'; -#if DEBUG - fprintf (stderr, "DEBUG: read %zd bytes from pty\n", rs); - fprintf (stderr, "DEBUG: buffer content: "); - debug_buffer (stderr, h->buffer); - fprintf (stderr, "\n"); -#endif + if (h->debug_fp) { + fprintf (h->debug_fp, "DEBUG: read %zd bytes from pty\n", rs); + fprintf (h->debug_fp, "DEBUG: buffer content: "); + debug_buffer (h->debug_fp, h->buffer); + fprintf (h->debug_fp, "\n"); + } try_match: /* See if there is a full or partial match against any regexp. */ @@ -395,28 +390,32 @@ mexp_expect (mexp_h *h, const mexp_regexp *regexps, int *ovector, int ovecsize) } } -int -mexp_printf (mexp_h *h, const char *fs, ...) +static int mexp_vprintf (mexp_h *h, int password, const char *fs, va_list args) + __attribute__((format(printf,3,0))); + +static int +mexp_vprintf (mexp_h *h, int password, const char *fs, va_list args) { - va_list args; char *msg; int len; size_t n; ssize_t r; char *p; - va_start (args, fs); len = vasprintf (&msg, fs, args); - va_end (args); if (len < 0) return -1; -#if DEBUG - fprintf (stderr, "DEBUG: writing: "); - debug_buffer (stderr, msg); - fprintf (stderr, "\n"); -#endif + if (h->debug_fp) { + if (!password) { + fprintf (h->debug_fp, "DEBUG: writing: "); + debug_buffer (h->debug_fp, msg); + fprintf (h->debug_fp, "\n"); + } + else + fprintf (h->debug_fp, "DEBUG: writing the password\n"); + } n = len; p = msg; @@ -435,12 +434,35 @@ mexp_printf (mexp_h *h, const char *fs, ...) } int +mexp_printf (mexp_h *h, const char *fs, ...) +{ + int r; + va_list args; + + va_start (args, fs); + r = mexp_vprintf (h, 0, fs, args); + va_end (args); + return r; +} + +int +mexp_printf_password (mexp_h *h, const char *fs, ...) +{ + int r; + va_list args; + + va_start (args, fs); + r = mexp_vprintf (h, 1, fs, args); + va_end (args); + return r; +} + +int mexp_send_interrupt (mexp_h *h) { return write (h->fd, "\003", 1); } -#if DEBUG /* Print escaped buffer to fp. */ static void debug_buffer (FILE *fp, char *buf) @@ -465,5 +487,3 @@ debug_buffer (FILE *fp, char *buf) buf++; } } -#endif - diff --git a/miniexpect.h b/miniexpect.h index e4d6010..14d8236 100644 --- a/miniexpect.h +++ b/miniexpect.h @@ -29,6 +29,7 @@ #ifndef MINIEXPECT_H_ #define MINIEXPECT_H_ +#include <stdio.h> #include <unistd.h> #include <pcre.h> @@ -44,6 +45,7 @@ struct mexp_h { ssize_t next_match; size_t read_size; int pcre_error; + FILE *debug_fp; void *user1; void *user2; void *user3; @@ -62,6 +64,8 @@ typedef struct mexp_h mexp_h; #define mexp_get_read_size(h) ((h)->read_size) #define mexp_set_read_size(h, size) ((h)->read_size = (size)) #define mexp_get_pcre_error(h) ((h)->pcre_error) +#define mexp_set_debug_file(h, fp) ((h)->debug_fp = (fp)) +#define mexp_get_debug_file(h) ((h)->debug_fp) /* Spawn a subprocess. */ extern mexp_h *mexp_spawnvf (unsigned flags, const char *file, char **argv); @@ -99,6 +103,8 @@ extern int mexp_expect (mexp_h *h, const mexp_regexp *regexps, /* Sending commands, keypresses. */ extern int mexp_printf (mexp_h *h, const char *fs, ...) __attribute__((format(printf,2,3))); +extern int mexp_printf_password (mexp_h *h, const char *fs, ...) + __attribute__((format(printf,2,3))); extern int mexp_send_interrupt (mexp_h *h); #endif /* MINIEXPECT_H_ */ diff --git a/miniexpect.pod b/miniexpect.pod index cd008fc..fe76979 100644 --- a/miniexpect.pod +++ b/miniexpect.pod @@ -177,6 +177,18 @@ returned by L<pcre_exec(3)>, and so you can call it like this: =back +B<void mexp_set_debug_file (mexp *h, FILE *fp);> + +B<FILE *mexp_get_debug_file (mexp *h);> + +Set or get the debug file of the handle. To enable debugging, pass a +non-C<NULL> file handle, eg. C<stderr>. To disable debugging, pass +C<NULL>. Debugging messages are printed on the file handle. + +Note that all output and input gets printed, including passwords. To +prevent passwords from being printed, modify your code to call +C<mexp_printf_password> instead of C<mexp_printf>. + The following fields in the handle do not have methods, but can be accessed directly instead: @@ -415,6 +427,8 @@ However we also provide a convenience function: B<int mexp_printf (mexp_h *h, const char *fs, ...);> +B<int mexp_printf_password (mexp_h *h, const char *fs, ...);> + This returns the number of bytes, if the whole message was written OK. If there was an error, -1 is returned and the error is available in C<errno>. @@ -435,6 +449,13 @@ send a command followed by a newline you have to do something like: mexp_printf (h, "exit\n"); +=item * + +C<mexp_printf_password> works identically to C<mexp_printf> except +that the output is I<not> sent to the debugging file if debugging is +enabled. As the name suggests, use this for passwords so that they +don't appear in debugging output. + =back B<int mexp_send_interrupt (mexp_h *h);> -- 2.13.2